Publications

Publications by authors of the Institute of Computer Science

You will only find publications by authors who manage their list of publications on www.bibsonomy.org. (and member of https://www.bibsonomy.org/group/csuniwue)

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2023[ to top ]

A Trace-driven Performance Evaluation of Hash-based Task Placement Algorithms for Cache-enabled Serverless Computing Talluri, Sacheendra; Herbst, Nikolas; Abad, Cristina; Trivedi, Animesh; Iosup, Alexandru in 2023 ACM International Conference on Computing Frontiers (CF ’23) (2023).
- [ BibTeX ]
@inproceedings{2023-cf-hash-task-placement, author = {Talluri, Sacheendra and Herbst, Nikolas and Abad, Cristina and Trivedi, Animesh and Iosup, Alexandru}, booktitle = {2023 ACM International Conference on Computing Frontiers (CF '23)}, keywords = {myown}, title = {A Trace-driven Performance Evaluation of Hash-based Task Placement Algorithms for Cache-enabled Serverless Computing}, year = 2023 }
Recommendation of Secure Group Communication Schemes using Multi Objective Optimization Prantl, Thomas; Bauer, André; Iffländer, Lukas; Krupitzer, Christian; Kounev, Samuel in International Journal of Information Security (2023).
- [ BibTeX ]
@article{PrBaIfKrKo_IJoIS_SGC_Pareto, author = {Prantl, Thomas and Bauer, André and Iffländer, Lukas and Krupitzer, Christian and Kounev, Samuel}, journal = {International Journal of Information Security}, keywords = {t_journalmagazine}, title = {Recommendation of Secure Group Communication Schemes using Multi Objective Optimization}, year = 2023 }
Searching for the Ground Truth: Assessing the Similarity of Benchmarking Runs Bauer, Andr\’{e}; Straesser, Martin; Leznik, Mark; Beierlieb, Lukas; Hadry, Marius; Hudson, Nathaniel; Chard, Kyle; Kounev, Samuel; Foster, Ian in Companion of the 2023 ACM/SPEC International Conference on Performance Engineering, ICPE ’23 Companion (2023). 95–99.
- [ Abstract ]
- [ BibTeX ]
- [ URL ]
Stable and repeatable measurements are essential for comparing the performance of different systems or applications, and benchmarks are used to ensure accuracy and replication. However, if the corresponding measurements are not stable and repeatable, wrong conclusions can be drawn. To facilitate the task of determining whether the measurements are similar, we used a data set of 586 micro-benchmarks to (i) analyze the data set itself, (ii) examine our previous approach, and (iii) propose and evaluate a heuristic. To evaluate the different approaches, we perform a peer review to assess the dissimilarity of the benchmark runs. Our results show that this task is challenging even for humans and that our heuristic exhibits a sensitivity of 92%.

@inproceedings{10.1145/3578245.3584693, abstract = {Stable and repeatable measurements are essential for comparing the performance of different systems or applications, and benchmarks are used to ensure accuracy and replication. However, if the corresponding measurements are not stable and repeatable, wrong conclusions can be drawn. To facilitate the task of determining whether the measurements are similar, we used a data set of 586 micro-benchmarks to (i) analyze the data set itself, (ii) examine our previous approach, and (iii) propose and evaluate a heuristic. To evaluate the different approaches, we perform a peer review to assess the dissimilarity of the benchmark runs. Our results show that this task is challenging even for humans and that our heuristic exhibits a sensitivity of 92%.}, address = {New York, NY, USA}, author = {Bauer, Andr\'{e} and Straesser, Martin and Leznik, Mark and Beierlieb, Lukas and Hadry, Marius and Hudson, Nathaniel and Chard, Kyle and Kounev, Samuel and Foster, Ian}, booktitle = {Companion of the 2023 ACM/SPEC International Conference on Performance Engineering}, keywords = {myown}, pages = {95–99}, publisher = {Association for Computing Machinery}, series = {ICPE '23 Companion}, title = {Searching for the Ground Truth: Assessing the Similarity of Benchmarking Runs}, year = 2023 }
Searching for the Ground Truth: Assessing the Similarity of Benchmarking Runs Bauer, Andr\’{e}; Straesser, Martin; Leznik, Mark; Beierlieb, Lukas; Hadry, Marius; Hudson, Nathaniel; Chard, Kyle; Kounev, Samuel; Foster, Ian in Companion of the 2023 ACM/SPEC International Conference on Performance Engineering, ICPE ’23 Companion (2023). 95–99.
- [ Abstract ]
- [ BibTeX ]
- [ URL ]
Stable and repeatable measurements are essential for comparing the performance of different systems or applications, and benchmarks are used to ensure accuracy and replication. However, if the corresponding measurements are not stable and repeatable, wrong conclusions can be drawn. To facilitate the task of determining whether the measurements are similar, we used a data set of 586 micro-benchmarks to (i) analyze the data set itself, (ii) examine our previous approach, and (iii) propose and evaluate a heuristic. To evaluate the different approaches, we perform a peer review to assess the dissimilarity of the benchmark runs. Our results show that this task is challenging even for humans and that our heuristic exhibits a sensitivity of 92%.

@inproceedings{10.1145/3578245.3584693, abstract = {Stable and repeatable measurements are essential for comparing the performance of different systems or applications, and benchmarks are used to ensure accuracy and replication. However, if the corresponding measurements are not stable and repeatable, wrong conclusions can be drawn. To facilitate the task of determining whether the measurements are similar, we used a data set of 586 micro-benchmarks to (i) analyze the data set itself, (ii) examine our previous approach, and (iii) propose and evaluate a heuristic. To evaluate the different approaches, we perform a peer review to assess the dissimilarity of the benchmark runs. Our results show that this task is challenging even for humans and that our heuristic exhibits a sensitivity of 92%.}, address = {New York, NY, USA}, author = {Bauer, Andr\'{e} and Straesser, Martin and Leznik, Mark and Beierlieb, Lukas and Hadry, Marius and Hudson, Nathaniel and Chard, Kyle and Kounev, Samuel and Foster, Ian}, booktitle = {Companion of the 2023 ACM/SPEC International Conference on Performance Engineering}, keywords = {myown}, pages = {95–99}, publisher = {Association for Computing Machinery}, series = {ICPE '23 Companion}, title = {Searching for the Ground Truth: Assessing the Similarity of Benchmarking Runs}, year = 2023 }
Are Embodied Avatars Harmful to Our Self-Experience? The Impact of Virtual Embodiment on Body Awareness D\"{o}llinger, Nina; Wolf, Erik; Botsch, Mario; Latoschik, Marc Erich; Wienrich, Carolin in Proceedings of the 2023 CHI Conference on Human Factors in Computing Systems, CHI ’23 (2023).
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Virtual Reality (VR) allows us to replace our visible body with a virtual self-representation (avatar) and to explore its effects on our body perception. While the feeling of owning and controlling a virtual body is widely researched, how VR affects the awareness of internal body signals (body awareness) remains open. Forty participants performed moving meditation tasks in reality and VR, either facing their mirror image or not. Both the virtual environment and avatars photorealistically matched their real counterparts. We found a negative effect of VR on body awareness, mediated by feeling embodied in and changed by the avatar. Further, we revealed a negative effect of a mirror on body awareness. Our results indicate that assessing body awareness should be essential in evaluating VR designs and avatar embodiment aiming at mental health, as even a scenario as close to reality as possible can distract users from their internal body signals.

@inproceedings{10.1145/3544548.3580918, abstract = {Virtual Reality (VR) allows us to replace our visible body with a virtual self-representation (avatar) and to explore its effects on our body perception. While the feeling of owning and controlling a virtual body is widely researched, how VR affects the awareness of internal body signals (body awareness) remains open. Forty participants performed moving meditation tasks in reality and VR, either facing their mirror image or not. Both the virtual environment and avatars photorealistically matched their real counterparts. We found a negative effect of VR on body awareness, mediated by feeling embodied in and changed by the avatar. Further, we revealed a negative effect of a mirror on body awareness. Our results indicate that assessing body awareness should be essential in evaluating VR designs and avatar embodiment aiming at mental health, as even a scenario as close to reality as possible can distract users from their internal body signals.}, address = {New York, NY, USA}, author = {D\"{o}llinger, Nina and Wolf, Erik and Botsch, Mario and Latoschik, Marc Erich and Wienrich, Carolin}, booktitle = {Proceedings of the 2023 CHI Conference on Human Factors in Computing Systems}, keywords = {virtual}, publisher = {Association for Computing Machinery}, series = {CHI '23}, title = {Are Embodied Avatars Harmful to Our Self-Experience? The Impact of Virtual Embodiment on Body Awareness}, year = 2023 }
How Do Employees Imagine AI They Want to Work with: A Drawing Study Straka, Samantha; Koch, Martin Jakobus; Carolus, Astrid; Latoschik, Marc Erich; Wienrich, Carolin in Extended Abstracts of the 2023 CHI Conference on Human Factors in Computing Systems, CHI EA ’23 (2023).
- [ Abstract ]
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Perceptions about AI influence the attribution of characteristics and the interaction with AI. To find out how workers imagine an AI they would like to work with and what characteristics they attribute to it, we asked 174 working individuals to draw an AI they would like to work with, to report five adjectives they associate with their drawing and to evaluate the drawn and three other, typical AI representations (e.g. robot, smartphone) either presented as male or female. Participants mainly drew humanoid or robotic AIs. The adjectives that describe AI mainly referred to the inner characteristics, capabilities, shape, or relationship types. Regarding the evaluation, we identified four dimensions (warmth, competence, animacy, size) that can be reproduced for male and female AIs and different AI representations. This work addresses diverse conceptions of AI in the workplace and shows that human-centered AI development is necessary to address the huge design space.

@inproceedings{10.1145/3544549.3585631, abstract = {Perceptions about AI influence the attribution of characteristics and the interaction with AI. To find out how workers imagine an AI they would like to work with and what characteristics they attribute to it, we asked 174 working individuals to draw an AI they would like to work with, to report five adjectives they associate with their drawing and to evaluate the drawn and three other, typical AI representations (e.g. robot, smartphone) either presented as male or female. Participants mainly drew humanoid or robotic AIs. The adjectives that describe AI mainly referred to the inner characteristics, capabilities, shape, or relationship types. Regarding the evaluation, we identified four dimensions (warmth, competence, animacy, size) that can be reproduced for male and female AIs and different AI representations. This work addresses diverse conceptions of AI in the workplace and shows that human-centered AI development is necessary to address the huge design space.}, address = {New York, NY, USA}, author = {Straka, Samantha and Koch, Martin Jakobus and Carolus, Astrid and Latoschik, Marc Erich and Wienrich, Carolin}, booktitle = {Extended Abstracts of the 2023 CHI Conference on Human Factors in Computing Systems}, keywords = {warmth}, publisher = {Association for Computing Machinery}, series = {CHI EA '23}, title = {How Do Employees Imagine AI They Want to Work with: A Drawing Study}, year = 2023 }
Share and Multiply: Modeling Communication and Generated Traffic in Private WhatsApp Groups Seufert, Anika; Poignée, Fabian; Seufert, Michael; Hoßfeld, Tobias in IEEE Access (2023). 11 25401–25414.
- [ Abstract ]
- [ BibTeX ]
Group-based communication is a highly popular communication paradigm, which is especially prominent in mobile instant messaging (MIM) applications, such as WhatsApp. Chat groups in MIM applications facilitate the sharing of various types of messages (e.g., text, voice, image, video) among a large number of participants. As each message has to be transmitted to every other member of the group, which multiplies the traffic, this has a massive impact on the underlying communication networks. However, most chat groups are private and network operators cannot obtain deep insights into MIM communication via network measurements due to end-to-end encryption. Thus, the generation of traffic is not well understood, given that it depends on sizes of communication groups, speed of communication, and exchanged message types. In this work, we provide a huge data set of 5,956 private WhatsApp chat histories, which contains over 76 million messages from more than 117,000 users. We describe and model the properties of chat groups and users, and the communication within these chat groups, which gives unprecedented insights into private MIM communication. In addition, we conduct exemplary measurements for the most popular message types, which empower the provided models to estimate the traffic over time in a chat group.

@article{info3-article-2023-2, abstract = {Group-based communication is a highly popular communication paradigm, which is especially prominent in mobile instant messaging (MIM) applications, such as WhatsApp. Chat groups in MIM applications facilitate the sharing of various types of messages (e.g., text, voice, image, video) among a large number of participants. As each message has to be transmitted to every other member of the group, which multiplies the traffic, this has a massive impact on the underlying communication networks. However, most chat groups are private and network operators cannot obtain deep insights into MIM communication via network measurements due to end-to-end encryption. Thus, the generation of traffic is not well understood, given that it depends on sizes of communication groups, speed of communication, and exchanged message types. In this work, we provide a huge data set of 5,956 private WhatsApp chat histories, which contains over 76 million messages from more than 117,000 users. We describe and model the properties of chat groups and users, and the communication within these chat groups, which gives unprecedented insights into private MIM communication. In addition, we conduct exemplary measurements for the most popular message types, which empower the provided models to estimate the traffic over time in a chat group.}, author = {Seufert, Anika and Poignée, Fabian and Seufert, Michael and Hoßfeld, Tobias}, journal = {IEEE Access}, keywords = {ucn}, month = 3, pages = {25401 - 25414}, title = {Share and Multiply: Modeling Communication and Generated Traffic in Private WhatsApp Groups}, volume = 11, year = 2023 }
On Profiling, Benchmarking and Behavioral Analysis of SDN Architecture Under DDoS Attacks Huu Thanh, Nguyen; NgocTuan, Nguyen; AnhKhoa, Dang; CongTuan, Le; TrungKien, Nguyen; XuanDung, Nguyen; QuynhThu, Ngo; Wamser, Florian in Journal of Network and Systems Management (2023).
- [ Abstract ]
- [ BibTeX ]
Software-Defined Networking (SDN) has attracted much attention from research and industrial communities recently as it is more agile and flexible compared to conventional networking technology in offering new network functions and services. By separating the network control functions from the forwarding devices and placing them in a centralized, softwarized and programmable SDN controller, new network functions and services can be easily added into the network in an on-demand manner. However, the centralized control paradigm and the flow-based forwarding principle make the SDN architecture more fragile and vulnerable to malicious actions, such as cyber hijacking or DDoS attacks. In this paper, we focus on analyzing and evaluating negative impacts of DDoS attacks on the SDN architecture. By performing stress tests, the performance of such common SDN controllers as POX, Ryu and Floodlight under DDoS attacks is benchmarked, along with their impacts on the SDN switch and OpenFlow channel. We also address some new threats and vulnerabilities introduced by the nature of SDN.

@article{info3-article-2023-1, abstract = {Software-Defined Networking (SDN) has attracted much attention from research and industrial communities recently as it is more agile and flexible compared to conventional networking technology in offering new network functions and services. By separating the network control functions from the forwarding devices and placing them in a centralized, softwarized and programmable SDN controller, new network functions and services can be easily added into the network in an on-demand manner. However, the centralized control paradigm and the flow-based forwarding principle make the SDN architecture more fragile and vulnerable to malicious actions, such as cyber hijacking or DDoS attacks. In this paper, we focus on analyzing and evaluating negative impacts of DDoS attacks on the SDN architecture. By performing stress tests, the performance of such common SDN controllers as POX, Ryu and Floodlight under DDoS attacks is benchmarked, along with their impacts on the SDN switch and OpenFlow channel. We also address some new threats and vulnerabilities introduced by the nature of SDN.}, author = {Huu Thanh, Nguyen and NgocTuan, Nguyen and AnhKhoa, Dang and CongTuan, Le and TrungKien, Nguyen and XuanDung, Nguyen and QuynhThu, Ngo and Wamser, Florian}, journal = {Journal of Network and Systems Management}, keywords = {myown}, month = 3, title = {On Profiling, Benchmarking and Behavioral Analysis of SDN Architecture Under DDoS Attacks}, year = 2023 }
Recommendation of Secure Group Communication Schemes using Multi Objective Optimization Prantl, Thomas; Bauer, André; Iffländer, Lukas; Krupitzer, Christian; Kounev, Samuel in International Journal of Information Security (2023).
- [ BibTeX ]
- [ URL ]
@article{PrBaIfKrKo_IJoIS_SGC_Pareto, author = {Prantl, Thomas and Bauer, André and Iffländer, Lukas and Krupitzer, Christian and Kounev, Samuel}, journal = {International Journal of Information Security}, keywords = {t_journalmagazine}, title = {Recommendation of Secure Group Communication Schemes using Multi Objective Optimization}, year = 2023 }
Holographic Augmented Reality Mirrors for Daily Self-Reflection on the Own Body Image Fiedler, Marie Luisa; Wolf, Erik; Wienrich, Carolin; Latoschik, Marc Erich in Integrating Individual and Social Contexts into Self-Reflection Technologies Workshop (WS28, CHI ’23) (2023). 1–4.
- [ Abstract ]
- [ BibTeX ]
- [ URL ]
Mirror self-reflection can help us to develop a deeper understanding and appreciation of our body. Due to technological advancements, holographic augmented reality (AR) mirrors can create realistic visualizations of virtual humans that can represent one's appearance in an altered way while remaining in a familiar environment. Further developing those mirrors opens a new field for use in everyday life. In this work, we outline possible future scenarios where AR mirrors can empower individuals to visualize their emotions, thought patterns, and discrepancies related to their physical body and mental body image. Thus, AR mirrors can encourage their self-reflection, promote a positive and healthy relationship with their bodies, or motivate them to take action to improve their well-being.

@inproceedings{fiedler2023holographic, abstract = {Mirror self-reflection can help us to develop a deeper understanding and appreciation of our body. Due to technological advancements, holographic augmented reality (AR) mirrors can create realistic visualizations of virtual humans that can represent one's appearance in an altered way while remaining in a familiar environment. Further developing those mirrors opens a new field for use in everyday life. In this work, we outline possible future scenarios where AR mirrors can empower individuals to visualize their emotions, thought patterns, and discrepancies related to their physical body and mental body image. Thus, AR mirrors can encourage their self-reflection, promote a positive and healthy relationship with their bodies, or motivate them to take action to improve their well-being.}, author = {Fiedler, Marie Luisa and Wolf, Erik and Wienrich, Carolin and Latoschik, Marc Erich}, booktitle = {Integrating Individual and Social Contexts into Self-Reflection Technologies Workshop (WS28, CHI ’23)}, keywords = {vitras}, pages = {1-4}, title = {Holographic Augmented Reality Mirrors for Daily Self-Reflection on the Own Body Image}, year = 2023 }
Searching for the Ground Truth: Assessing the Similarity of Benchmarking Runs Bauer, Andr\’{e}; Straesser, Martin; Leznik, Mark; Beierlieb, Lukas; Hadry, Marius; Hudson, Nathaniel; Chard, Kyle; Kounev, Samuel; Foster, Ian in Companion of the 2023 ACM/SPEC International Conference on Performance Engineering, ICPE ’23 Companion (2023). 95–99.
- [ Abstract ]
- [ BibTeX ]
- [ URL ]
Stable and repeatable measurements are essential for comparing the performance of different systems or applications, and benchmarks are used to ensure accuracy and replication. However, if the corresponding measurements are not stable and repeatable, wrong conclusions can be drawn. To facilitate the task of determining whether the measurements are similar, we used a data set of 586 micro-benchmarks to (i) analyze the data set itself, (ii) examine our previous approach, and (iii) propose and evaluate a heuristic. To evaluate the different approaches, we perform a peer review to assess the dissimilarity of the benchmark runs. Our results show that this task is challenging even for humans and that our heuristic exhibits a sensitivity of 92%.

@inproceedings{10.1145/3578245.3584693, abstract = {Stable and repeatable measurements are essential for comparing the performance of different systems or applications, and benchmarks are used to ensure accuracy and replication. However, if the corresponding measurements are not stable and repeatable, wrong conclusions can be drawn. To facilitate the task of determining whether the measurements are similar, we used a data set of 586 micro-benchmarks to (i) analyze the data set itself, (ii) examine our previous approach, and (iii) propose and evaluate a heuristic. To evaluate the different approaches, we perform a peer review to assess the dissimilarity of the benchmark runs. Our results show that this task is challenging even for humans and that our heuristic exhibits a sensitivity of 92%.}, address = {New York, NY, USA}, author = {Bauer, Andr\'{e} and Straesser, Martin and Leznik, Mark and Beierlieb, Lukas and Hadry, Marius and Hudson, Nathaniel and Chard, Kyle and Kounev, Samuel and Foster, Ian}, booktitle = {Companion of the 2023 ACM/SPEC International Conference on Performance Engineering}, keywords = {myown}, pages = {95–99}, publisher = {Association for Computing Machinery}, series = {ICPE '23 Companion}, title = {Searching for the Ground Truth: Assessing the Similarity of Benchmarking Runs}, year = 2023 }
Virtual-to-Physical Surface Alignment and Refinement Techniques for Handwriting, Sketching, and Selection in XR Kern, Florian; Tschanter, Jonathan; Latoschik, Marc Erich in 2023 IEEE Conference on Virtual Reality and 3D User Interfaces Abstracts and Workshops (VRW) (2023). 502–506.
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- [ BibTeX ]
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The alignment of virtual to physical surfaces is essential to improve symbolic input and selection in XR. Previous techniques optimized for efficiency can lead to inaccuracies. We investigate regression-based refinement techniques and introduce a surface accuracy eval-uation. The results revealed that refinement techniques can highly improve surface accuracy and show that accuracy depends on the gesture shape and surface dimension. Our reference implementation and dataset are publicly available.

@inproceedings{10108564, abstract = {The alignment of virtual to physical surfaces is essential to improve symbolic input and selection in XR. Previous techniques optimized for efficiency can lead to inaccuracies. We investigate regression-based refinement techniques and introduce a surface accuracy eval-uation. The results revealed that refinement techniques can highly improve surface accuracy and show that accuracy depends on the gesture shape and surface dimension. Our reference implementation and dataset are publicly available.}, author = {Kern, Florian and Tschanter, Jonathan and Latoschik, Marc Erich}, booktitle = {2023 IEEE Conference on Virtual Reality and 3D User Interfaces Abstracts and Workshops (VRW)}, keywords = {myown}, month = {March}, pages = {502-506}, title = {Virtual-to-Physical Surface Alignment and Refinement Techniques for Handwriting, Sketching, and Selection in XR}, year = 2023 }
Searching for the Ground Truth: Assessing the Similarity of Benchmarking Runs Bauer, Andr\’{e}; Straesser, Martin; Leznik, Mark; Beierlieb, Lukas; Hadry, Marius; Hudson, Nathaniel; Chard, Kyle; Kounev, Samuel; Foster, Ian in Companion of the 2023 ACM/SPEC International Conference on Performance Engineering, ICPE ’23 Companion (2023). 95–99.
- [ Abstract ]
- [ BibTeX ]
- [ URL ]
Stable and repeatable measurements are essential for comparing the performance of different systems or applications, and benchmarks are used to ensure accuracy and replication. However, if the corresponding measurements are not stable and repeatable, wrong conclusions can be drawn. To facilitate the task of determining whether the measurements are similar, we used a data set of 586 micro-benchmarks to (i) analyze the data set itself, (ii) examine our previous approach, and (iii) propose and evaluate a heuristic. To evaluate the different approaches, we perform a peer review to assess the dissimilarity of the benchmark runs. Our results show that this task is challenging even for humans and that our heuristic exhibits a sensitivity of 92%.

@inproceedings{10.1145/3578245.3584693, abstract = {Stable and repeatable measurements are essential for comparing the performance of different systems or applications, and benchmarks are used to ensure accuracy and replication. However, if the corresponding measurements are not stable and repeatable, wrong conclusions can be drawn. To facilitate the task of determining whether the measurements are similar, we used a data set of 586 micro-benchmarks to (i) analyze the data set itself, (ii) examine our previous approach, and (iii) propose and evaluate a heuristic. To evaluate the different approaches, we perform a peer review to assess the dissimilarity of the benchmark runs. Our results show that this task is challenging even for humans and that our heuristic exhibits a sensitivity of 92%.}, address = {New York, NY, USA}, author = {Bauer, Andr\'{e} and Straesser, Martin and Leznik, Mark and Beierlieb, Lukas and Hadry, Marius and Hudson, Nathaniel and Chard, Kyle and Kounev, Samuel and Foster, Ian}, booktitle = {Companion of the 2023 ACM/SPEC International Conference on Performance Engineering}, keywords = {myown}, pages = {95–99}, publisher = {Association for Computing Machinery}, series = {ICPE '23 Companion}, title = {Searching for the Ground Truth: Assessing the Similarity of Benchmarking Runs}, year = 2023 }
MVNOCoreSim: A Digital Twin for Virtualized IoT-centric Mobile Core Networks Geissler, Stefan; Wamser, Florian; Bauer, Wolfgang; Gebert, Steffen; Kounev, Samuel; Hossfeld, Tobias in IEEE Internet of Things (2023).
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The rapid growth of connected devices has led to the implementation of IoT-centric platforms designed to provide connectivity for machine-to-machine type communication. Specifically, mobile virtual network operators (MVNOs) provide global service for IoT use cases by leveraging roaming in readily deployed physical networks. This global deployment of connected devices poses a significant challenge regarding the operation of centralized core networks with respect to dimensioning, scaling as well as system survivability in case of signaling incidents. Overload control mechanisms for IoT mobile networks offer a proactive solution for mitigating excessive signaling traffic from IoT devices in mobile core networks. However, global scaling and a heterogeneous composition of devices present network operators with additional challenges. To address these challenges, this work presents a detailed, protocol level simulation framework of a real-world IoT MVNO core network. We present both models for the expected IoT signaling load and the processing of signaling messages based on measurements in a live, production environment as well as a dedicated testbed. Finally, we present a case study on various overload mechanisms and identify critical performance characteristics to compare their performance. The results of this study categorize overload control mechanisms and shed light on the necessity for MVNOs to deal with the upcoming IoT traffic by defining appropriate overload control mechanisms in mobile core networks to ensure network survivability under unforeseen conditions.

@article{geissler2023mvnocoresim, abstract = {The rapid growth of connected devices has led to the implementation of IoT-centric platforms designed to provide connectivity for machine-to-machine type communication. Specifically, mobile virtual network operators (MVNOs) provide global service for IoT use cases by leveraging roaming in readily deployed physical networks. This global deployment of connected devices poses a significant challenge regarding the operation of centralized core networks with respect to dimensioning, scaling as well as system survivability in case of signaling incidents. Overload control mechanisms for IoT mobile networks offer a proactive solution for mitigating excessive signaling traffic from IoT devices in mobile core networks. However, global scaling and a heterogeneous composition of devices present network operators with additional challenges. To address these challenges, this work presents a detailed, protocol level simulation framework of a real-world IoT MVNO core network. We present both models for the expected IoT signaling load and the processing of signaling messages based on measurements in a live, production environment as well as a dedicated testbed. Finally, we present a case study on various overload mechanisms and identify critical performance characteristics to compare their performance. The results of this study categorize overload control mechanisms and shed light on the necessity for MVNOs to deal with the upcoming IoT traffic by defining appropriate overload control mechanisms in mobile core networks to ensure network survivability under unforeseen conditions.}, author = {Geissler, Stefan and Wamser, Florian and Bauer, Wolfgang and Gebert, Steffen and Kounev, Samuel and Hossfeld, Tobias}, journal = {IEEE Internet of Things}, keywords = {myown}, title = {MVNOCoreSim: A Digital Twin for Virtualized IoT-centric Mobile Core Networks}, year = 2023 }
An Empirical Study of Container Image Configurations and Their Impact on Start Times Straesser, Martin; Bauer, André; Leppich, Robert; Herbst, Nikolas; Chard, Kyle; Foster, Ian; Kounev, Samuel in 2023 IEEE/ACM 23rd International Symposium on Cluster, Cloud and Internet Computing (CCGrid) (2023).
- [ BibTeX ]
@inproceedings{straesser2023starttime, author = {Straesser, Martin and Bauer, André and Leppich, Robert and Herbst, Nikolas and Chard, Kyle and Foster, Ian and Kounev, Samuel}, booktitle = {2023 IEEE/ACM 23rd International Symposium on Cluster, Cloud and Internet Computing (CCGrid)}, keywords = {myown}, note = {In print.}, publisher = {IEEE}, title = {An Empirical Study of Container Image Configurations and Their Impact on Start Times}, year = 2023 }
An Evaluation of Other-Avatar Facial Animation Methods for Social VR Kullmann, Peter; Menzel, Timo; Botsch, Mario; Latoschik, Marc Erich in CHI Conference on Human Factors in Computing Systems (2023).
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We report a mixed-design study on the effect of facial animation method (static, synthesized, or tracked expressions) and its synchronization to speaker audio (in sync or delayed by the method’s inherent latency) on an avatar’s perceived naturalness and plausibility. We created a virtual human for an actor and recorded his spontaneous half-minute responses to conversation prompts. As a simulated immersive interaction, 44 participants unfamiliar with the actor observed and rated performances rendered with the avatar, each with the different facial animation methods. Half of them observed performances in sync and the others with the animation method’s latency. Results show audio synchronization did not influence ratings and static faces were rated less natural and less plausible than animated faces. Notably, synthesized expressions were rated as more natural and more plausible than tracked expressions. Moreover, ratings of verbal behavior naturalness differed in the same way. We discuss implications of these results for avatar-mediated communication.

@inproceedings{kullmann2023facialExpressionComparison, abstract = {We report a mixed-design study on the effect of facial animation method (static, synthesized, or tracked expressions) and its synchronization to speaker audio (in sync or delayed by the method’s inherent latency) on an avatar’s perceived naturalness and plausibility. We created a virtual human for an actor and recorded his spontaneous half-minute responses to conversation prompts. As a simulated immersive interaction, 44 participants unfamiliar with the actor observed and rated performances rendered with the avatar, each with the different facial animation methods. Half of them observed performances in sync and the others with the animation method’s latency. Results show audio synchronization did not influence ratings and static faces were rated less natural and less plausible than animated faces. Notably, synthesized expressions were rated as more natural and more plausible than tracked expressions. Moreover, ratings of verbal behavior naturalness differed in the same way. We discuss implications of these results for avatar-mediated communication.}, author = {Kullmann, Peter and Menzel, Timo and Botsch, Mario and Latoschik, Marc Erich}, booktitle = {CHI Conference on Human Factors in Computing Systems}, keywords = {myown}, publisher = {Association for Computing Machinery}, title = {An Evaluation of Other-Avatar Facial Animation Methods for Social VR}, year = 2023 }
An Empirical Study of Container Image Configurations and Their Impact on Start Times Straesser, Martin; Bauer, André; Leppich, Robert; Herbst, Nikolas; Chard, Kyle; Foster, Ian; Kounev, Samuel in 2023 IEEE/ACM 23rd International Symposium on Cluster, Cloud and Internet Computing (CCGrid) (2023).
- [ BibTeX ]
@inproceedings{straesser2023starttime, author = {Straesser, Martin and Bauer, André and Leppich, Robert and Herbst, Nikolas and Chard, Kyle and Foster, Ian and Kounev, Samuel}, booktitle = {2023 IEEE/ACM 23rd International Symposium on Cluster, Cloud and Internet Computing (CCGrid)}, keywords = {myown}, note = {In print.}, publisher = {IEEE}, title = {An Empirical Study of Container Image Configurations and Their Impact on Start Times}, year = 2023 }
Morphing Rectangular Duals Chaplick, Steven; Kindermann, Philipp; Klawitter, Jonathan; Rutter, Ignaz; Wolff, Alexander in Proc. 30th Int. Symp. Graph Drawing \& Network Vis. (GD’22), Lecture Notes in Computer Science, P. Angelini, R. von Hanxleden (eds.) (2023). (Vol. 13764) 389–403.
- [ BibTeX ]
@inproceedings{ckkrw-mrd-GD22, author = {Chaplick, Steven and Kindermann, Philipp and Klawitter, Jonathan and Rutter, Ignaz and Wolff, Alexander}, booktitle = {Proc. 30th Int. Symp. Graph Drawing \& Network Vis. (GD'22)}, editor = {Angelini, Patrizio and von Hanxleden, Reinhard}, keywords = {myown}, pages = {389–403}, publisher = {Springer-Verlag}, series = {Lecture Notes in Computer Science}, title = {Morphing Rectangular Duals}, volume = 13764, year = 2023 }
An Empirical Study of Container Image Configurations and Their Impact on Start Times Straesser, Martin; Bauer, André; Leppich, Robert; Herbst, Nikolas; Chard, Kyle; Foster, Ian; Kounev, Samuel in 2023 IEEE/ACM 23rd International Symposium on Cluster, Cloud and Internet Computing (CCGrid) (2023).
- [ BibTeX ]
@inproceedings{straesser2023starttime, author = {Straesser, Martin and Bauer, André and Leppich, Robert and Herbst, Nikolas and Chard, Kyle and Foster, Ian and Kounev, Samuel}, booktitle = {2023 IEEE/ACM 23rd International Symposium on Cluster, Cloud and Internet Computing (CCGrid)}, keywords = {myown}, note = {In print.}, publisher = {IEEE}, title = {An Empirical Study of Container Image Configurations and Their Impact on Start Times}, year = 2023 }
{femtoPro}: virtual-reality interactive training simulator of an ultrafast laser laboratory Brixner, Tobias; Mueller, Stefan; Müller, Andreas; Knote, Andreas; Schnepp, Wilhelm; Truman, Samuel; Vetter, Anne; von Mammen, Sebastian in Applied Physics B (2023). 129(5)
- [ BibTeX ]
- [ URL ]
@article{Brixner_2023, author = {Brixner, Tobias and Mueller, Stefan and Müller, Andreas and Knote, Andreas and Schnepp, Wilhelm and Truman, Samuel and Vetter, Anne and von Mammen, Sebastian}, journal = {Applied Physics B}, keywords = {virtual}, month = {apr}, number = 5, publisher = {Springer Science and Business Media {LLC}}, title = {{femtoPro}: virtual-reality interactive training simulator of an ultrafast laser laboratory}, volume = 129, year = 2023 }
Traffic-Adaptive Scheme for SDN Control Plane with Containerized Architecture AnhKhoa, Dang; TrungKiem, Nguyen; TrungKien, Nguyen; NgocTuan, Nguyen; Huu Thanh, Nguyen in 2023 17th International Conference on Ubiquitous Information Management and Communication (IMCOM) (2023).
- [ Abstract ]
- [ BibTeX ]
Software-Defined Networking (SDN) is gaining attention for its flexibility in programmability. It enhances network configuration and provides global visibility for administrators via a single interface. However, the centralized nature of SDN exposes many issues in scalability and resiliency. In this paper, with the advent of cloud computing, we present a containerized architecture capable of fast scaling up and down based on traffic load for SDN control plane. With our novel traffic-adaptive algorithm, the results show that the proposed system is able to fit performance with high incoming new-flow requests and scale down underused controllers for resource efficiency.

@inproceedings{info3-inproceedings-2023-3, abstract = {Software-Defined Networking (SDN) is gaining attention for its flexibility in programmability. It enhances network configuration and provides global visibility for administrators via a single interface. However, the centralized nature of SDN exposes many issues in scalability and resiliency. In this paper, with the advent of cloud computing, we present a containerized architecture capable of fast scaling up and down based on traffic load for SDN control plane. With our novel traffic-adaptive algorithm, the results show that the proposed system is able to fit performance with high incoming new-flow requests and scale down underused controllers for resource efficiency.}, author = {AnhKhoa, Dang and TrungKiem, Nguyen and TrungKien, Nguyen and NgocTuan, Nguyen and Huu Thanh, Nguyen}, booktitle = {2023 17th International Conference on Ubiquitous Information Management and Communication (IMCOM)}, keywords = {myown}, month = 1, title = {Traffic-Adaptive Scheme for SDN Control Plane with Containerized Architecture}, year = 2023 }
SPEC Research Group Newsletter, Issue 12 Kounev, Samuel; van Hoorn, Andre; Straesser, Martin; Bauer, Andr{é} (2023, April).
- [ BibTeX ]
- [ URL ]
@misc{SPEC-RG-NEWSLETTER-12, author = {Kounev, Samuel and van Hoorn, Andre and Straesser, Martin and Bauer, Andr{é}}, keywords = {myown}, month = {April}, note = {Published by Standard Performance Evaluation Corporation (SPEC)}, title = {SPEC Research Group Newsletter, Issue 12}, year = 2023 }
Segmentierung und Verlaufskontrolle chronischer Wunden durch künstliche Intelligenz mithilfe einer mobilen App (WUNDERKINT Studie) Borst, Vanessa; Dege, Tassilo; Grän, Franziska; Hamrouni, Sandra; Michel, Daniel; Hager, Valerie; Goebeler, Matthias; Leppich, Robert; Kounev, Samuel; Schmieder, Astrid in Allergologie. JDDG: Journal der Deutschen Dermatologischen Gesellschaft (2023). (Vol. 21) 28–177.
- [ BibTeX ]
- [ URL ]
@incollection{borst_ddg23_v2, author = {Borst, Vanessa and Dege, Tassilo and Grän, Franziska and Hamrouni, Sandra and Michel, Daniel and Hager, Valerie and Goebeler, Matthias and Leppich, Robert and Kounev, Samuel and Schmieder, Astrid}, booktitle = {Allergologie. JDDG: Journal der Deutschen Dermatologischen Gesellschaft}, keywords = {myown}, month = {April}, note = {Poster Abstract (No. P322, pp. 175-176)}, number = {S1}, pages = {28-177}, publisher = {John Wiley & Sons Ltd.}, title = {Segmentierung und Verlaufskontrolle chronischer Wunden durch künstliche Intelligenz mithilfe einer mobilen App (WUNDERKINT Studie)}, volume = 21, year = 2023 }
Do you Agree? Contrasting Google’s Core Web Vitals and the Impact of Cookie Consent Banners with Actual Web QoE Wehner, Nikolas; Seufert, Michael; Schatz, Raimund; Hoßfeld, Tobias in Quality and User Experience (2023).
- [ Abstract ]
- [ BibTeX ]
Providing sophisticated web Quality of Experience (QoE) has become paramount for web service providers and network operators alike. Due to advances in web technologies (HTML5, respon- sive design, etc.), traditional web QoE models focusing mainly on loading times have to be refined and improved. In this work, we relate Google’s Core Web Vitals, a set of metrics for improving user experience, to the loading time aspects of web QoE, and investigate whether the Core Web Vitals and web QoE agree on the perceived experience. To this end, we first perform objective measurements in the web using Google’s Lighthouse. To close the gap be- tween metrics and experience, we complement these objective measurements with subjective assessment by performing multiple crowdsourcing QoE studies. For this purpose, we developed CWeQS, a customized framework to emulate the entire web page loading process, and ask users for their experience while controlling the Core Web Vitals, which is available to the public. To properly configure CWeQS for the planned QoE study and the crowdsourcing setup, we conduct pre-studies, in which we evaluate the importance of the loading strategy of a web page and the impor- tance of the user task. The obtained insights allow us to conduct the desired QoE studies for each of the Core Web Vitals. Furthermore, we assess the impact of cookie consent banners, which have become ubiquitous due to regulatory demands, on the Core Web Vitals and investigate their influence on web QoE. Our results suggest that the Core Web Vitals are much less predictive for web QoE than expected and that page loading times remain the main metric and influence factor in this context. We further observe that unobtrusive and acentric cookie consent banners are preferred by end-users and that addi- tional delays caused by interacting with consent banners in order to agree to or reject cookies should be accounted along with the actual page load time to reduce waiting times and thus to improve web QoE.

@article{info3-article-2023-3, abstract = {Providing sophisticated web Quality of Experience (QoE) has become paramount for web service providers and network operators alike. Due to advances in web technologies (HTML5, respon- sive design, etc.), traditional web QoE models focusing mainly on loading times have to be refined and improved. In this work, we relate Google’s Core Web Vitals, a set of metrics for improving user experience, to the loading time aspects of web QoE, and investigate whether the Core Web Vitals and web QoE agree on the perceived experience. To this end, we first perform objective measurements in the web using Google’s Lighthouse. To close the gap be- tween metrics and experience, we complement these objective measurements with subjective assessment by performing multiple crowdsourcing QoE studies. For this purpose, we developed CWeQS, a customized framework to emulate the entire web page loading process, and ask users for their experience while controlling the Core Web Vitals, which is available to the public. To properly configure CWeQS for the planned QoE study and the crowdsourcing setup, we conduct pre-studies, in which we evaluate the importance of the loading strategy of a web page and the impor- tance of the user task. The obtained insights allow us to conduct the desired QoE studies for each of the Core Web Vitals. Furthermore, we assess the impact of cookie consent banners, which have become ubiquitous due to regulatory demands, on the Core Web Vitals and investigate their influence on web QoE. Our results suggest that the Core Web Vitals are much less predictive for web QoE than expected and that page loading times remain the main metric and influence factor in this context. We further observe that unobtrusive and acentric cookie consent banners are preferred by end-users and that addi- tional delays caused by interacting with consent banners in order to agree to or reject cookies should be accounted along with the actual page load time to reduce waiting times and thus to improve web QoE.}, author = {Wehner, Nikolas and Seufert, Michael and Schatz, Raimund and Hoßfeld, Tobias}, journal = {Quality and User Experience}, keywords = {ucn}, title = {Do you Agree? Contrasting Google’s Core Web Vitals and the Impact of Cookie Consent Banners with Actual Web QoE}, year = 2023 }
Virtual reality in medical emergencies training: benefits, perceived stress, and learning success M{\"u}hling, Tobias; Sp{\"a}th, Isabelle; Backhaus, Joy; Milke, Nathalie; Oberd{\"o}rfer, Sebastian; Meining, Alexander; Latoschik, Marc Erich; K{\"o}nig, Sarah in Multimedia Systems (2023).
- [ Abstract ]
- [ BibTeX ]
Medical graduates lack procedural skills experience required to manage emergencies. Recent advances in virtual reality (VR)technology enable the creation of highly immersive learning environments representing easy-to-use and affordable solutionsfor training with simulation. However, the feasibility in compulsory teaching, possible side effects of immersion, perceivedstress, and didactic benefits have to be investigated systematically. VR-based training sessions using head-mounted displaysalongside a real-time dynamic physiology system were held by student assistants for small groups followed by debriefing witha tutor. In the pilot study, 36 students rated simulation sickness. In the main study, 97 students completed a virtual scenarioas active participants (AP) and 130 students as observers (OBS) from the first-person perspective on a monitor. Participantscompleted questionnaires for evaluation purposes and exploratory factor analysis was performed on the items. The extent ofsimulation sickness remained low to acceptable among participants of the pilot study. In the main study, students valued therealistic environment and guided practical exercise. AP perceived the degree of immersion as well as the estimated learn-ing success to be greater than OBS and proved to be more motivated post training. With respect to AP, the factor “sense ofcontrol” revealed a typical inverse U-shaped relationship to the scales “didactic value” and “individual learning benefit”.Summing up, curricular implementation of highly immersive VR-based training of emergencies proved feasible and founda high degree of acceptance among medical students. This study also provides insights into how different conceptions of perceived stress distinctively moderate subjective learning success.

@article{muhling:2023, abstract = {Medical graduates lack procedural skills experience required to manage emergencies. Recent advances in virtual reality (VR)technology enable the creation of highly immersive learning environments representing easy-to-use and affordable solutionsfor training with simulation. However, the feasibility in compulsory teaching, possible side effects of immersion, perceivedstress, and didactic benefits have to be investigated systematically. VR-based training sessions using head-mounted displaysalongside a real-time dynamic physiology system were held by student assistants for small groups followed by debriefing witha tutor. In the pilot study, 36 students rated simulation sickness. In the main study, 97 students completed a virtual scenarioas active participants (AP) and 130 students as observers (OBS) from the first-person perspective on a monitor. Participantscompleted questionnaires for evaluation purposes and exploratory factor analysis was performed on the items. The extent ofsimulation sickness remained low to acceptable among participants of the pilot study. In the main study, students valued therealistic environment and guided practical exercise. AP perceived the degree of immersion as well as the estimated learn-ing success to be greater than OBS and proved to be more motivated post training. With respect to AP, the factor “sense ofcontrol” revealed a typical inverse U-shaped relationship to the scales “didactic value” and “individual learning benefit”.Summing up, curricular implementation of highly immersive VR-based training of emergencies proved feasible and founda high degree of acceptance among medical students. This study also provides insights into how different conceptions of perceived stress distinctively moderate subjective learning success.}, author = {M{\"u}hling, Tobias and Sp{\"a}th, Isabelle and Backhaus, Joy and Milke, Nathalie and Oberd{\"o}rfer, Sebastian and Meining, Alexander and Latoschik, Marc Erich and K{\"o}nig, Sarah}, journal = {Multimedia Systems}, keywords = {myown}, publisher = {Springer Nature}, title = {Virtual reality in medical emergencies training: benefits, perceived stress, and learning success}, year = 2023 }
Segmentierung und Verlaufskontrolle chronischer Wunden durch künstliche Intelligenz mithilfe einer mobilen App (WUNDERKINT Studie) Borst, Vanessa; Dege, Tassilo; Grän, Franziska; Hamrouni, Sandra; Michel, Daniel; Hager, Valerie; Goebeler, Matthias; Leppich, Robert; Kounev, Samuel; Schmieder, Astrid in Allergologie. JDDG: Journal der Deutschen Dermatologischen Gesellschaft (2023). (Vol. 21) 28–177.
- [ BibTeX ]
- [ URL ]
@incollection{borst_ddg23_v2, author = {Borst, Vanessa and Dege, Tassilo and Grän, Franziska and Hamrouni, Sandra and Michel, Daniel and Hager, Valerie and Goebeler, Matthias and Leppich, Robert and Kounev, Samuel and Schmieder, Astrid}, booktitle = {Allergologie. JDDG: Journal der Deutschen Dermatologischen Gesellschaft}, keywords = {myown}, month = {April}, note = {Poster Abstract (No. P322, pp. 175-176)}, number = {S1}, pages = {28-177}, publisher = {John Wiley & Sons Ltd.}, title = {Segmentierung und Verlaufskontrolle chronischer Wunden durch künstliche Intelligenz mithilfe einer mobilen App (WUNDERKINT Studie)}, volume = 21, year = 2023 }
An Empirical Study of Container Image Configurations and Their Impact on Start Times Straesser, Martin; Bauer, André; Leppich, Robert; Herbst, Nikolas; Chard, Kyle; Foster, Ian; Kounev, Samuel in 2023 IEEE/ACM 23rd International Symposium on Cluster, Cloud and Internet Computing (CCGrid) (2023).
- [ BibTeX ]
@inproceedings{straesser2023starttime, author = {Straesser, Martin and Bauer, André and Leppich, Robert and Herbst, Nikolas and Chard, Kyle and Foster, Ian and Kounev, Samuel}, booktitle = {2023 IEEE/ACM 23rd International Symposium on Cluster, Cloud and Internet Computing (CCGrid)}, keywords = {myown}, note = {In print.}, publisher = {IEEE}, title = {An Empirical Study of Container Image Configurations and Their Impact on Start Times}, year = 2023 }
Work, Trade, Learn: Developing an Immersive Serious Game for History Education Fernes, David; Oberdörfer, Sebastian; Latoschik, Marc Erich in 2023 9th International Conference of the Immersive Learning Research Network (iLRN) (2023).
- [ Abstract ]
- [ BibTeX ]
- [ URL ]
History education often struggles with a lack of interest from students. Serious games can help make learning about history more engaging. Students can directly experience situations of the past as well as interact and communicate with agents representing people of the respective era. This allows for situated learning. Besides using computer screens, the gameplay can also be experienced using immersive Virtual Reality (VR). VR adds an additional spatial level and can further increase the engagement as well as vividness. To investigate the benefits of using VR for serious games targeting the learning of history, we developed a serious game for desktop-3D and VR. Our serious game puts a player into the role of a medieval miller’s apprentice. Following a situated learning approach, the learner operates a mill and interacts with several other characters. These agents discuss relevant facts of the medieval life, thus enabling the construction of knowledge about the life in medieval towns. An evaluation showed that the game in general was successful in increasing the user’s knowledge about the covered topics as well as their topic interest in history. Whether the immersive VR or the simple desktop version of the application was used did not have any influence on these results. Additional feedback was gathered to improve the game further in the future.

@inproceedings{fernes2023trade, abstract = {History education often struggles with a lack of interest from students. Serious games can help make learning about history more engaging. Students can directly experience situations of the past as well as interact and communicate with agents representing people of the respective era. This allows for situated learning. Besides using computer screens, the gameplay can also be experienced using immersive Virtual Reality (VR). VR adds an additional spatial level and can further increase the engagement as well as vividness. To investigate the benefits of using VR for serious games targeting the learning of history, we developed a serious game for desktop-3D and VR. Our serious game puts a player into the role of a medieval miller’s apprentice. Following a situated learning approach, the learner operates a mill and interacts with several other characters. These agents discuss relevant facts of the medieval life, thus enabling the construction of knowledge about the life in medieval towns. An evaluation showed that the game in general was successful in increasing the user’s knowledge about the covered topics as well as their topic interest in history. Whether the immersive VR or the simple desktop version of the application was used did not have any influence on these results. Additional feedback was gathered to improve the game further in the future.}, author = {Fernes, David and Oberdörfer, Sebastian and Latoschik, Marc Erich}, booktitle = {2023 9th International Conference of the Immersive Learning Research Network (iLRN)}, keywords = {oberdoerfer}, note = {to be published}, title = {Work, Trade, Learn: Developing an Immersive Serious Game for History Education}, year = 2023 }
SPEC Research Group Newsletter, Issue 12 Kounev, Samuel; van Hoorn, Andre; Straesser, Martin; Bauer, Andr{é} (2023, April).
- [ BibTeX ]
- [ URL ]
@misc{SPEC-RG-NEWSLETTER-12, author = {Kounev, Samuel and van Hoorn, Andre and Straesser, Martin and Bauer, Andr{é}}, keywords = {myown}, month = {April}, note = {Published by Standard Performance Evaluation Corporation (SPEC)}, title = {SPEC Research Group Newsletter, Issue 12}, year = 2023 }
Explainable Data-Driven QoE Modelling using XAI Wehner, Nikolas; Seufert, Anika; Hoßfeld, Tobias; Seufert, Michael in 15th International Conference on Quality of Multimedia Experience (QoMEX) (2023).
- [ Abstract ]
- [ BibTeX ]
Data-driven QoE modelling using Machine Learning (ML) allows to reduce the modelling bias and to continuously integrate new QoE results into the QoE model, which can improve its generalizability. The downside is that the majority of ML models are black-box models, which prevent to obtain insights about QoE influence factors and their fundamental relationships that are highly relevant for researchers and providers of services and networks. However, recent advances in the field of eXplainable Artificial Intelligence (XAI) resolve these issues. Thus, XAI allows to benefit from data-driven QoE modelling to obtain generalizable QoE models, and at the same time to understand what QoE factors are relevant and how they affect the QoE score. In this work, we showcase the feasibility of explainable data-driven QoE modelling for video streaming, since video streaming QoE has been well researched, and thus, allows us to validate our results. Finally, we discuss opportunities and challenges of deploying XAI for QoE modelling.

@inproceedings{info3-inproceedings-2023-4, abstract = {Data-driven QoE modelling using Machine Learning (ML) allows to reduce the modelling bias and to continuously integrate new QoE results into the QoE model, which can improve its generalizability. The downside is that the majority of ML models are black-box models, which prevent to obtain insights about QoE influence factors and their fundamental relationships that are highly relevant for researchers and providers of services and networks. However, recent advances in the field of eXplainable Artificial Intelligence (XAI) resolve these issues. Thus, XAI allows to benefit from data-driven QoE modelling to obtain generalizable QoE models, and at the same time to understand what QoE factors are relevant and how they affect the QoE score. In this work, we showcase the feasibility of explainable data-driven QoE modelling for video streaming, since video streaming QoE has been well researched, and thus, allows us to validate our results. Finally, we discuss opportunities and challenges of deploying XAI for QoE modelling.}, address = {Ghent, Belgium}, author = {Wehner, Nikolas and Seufert, Anika and Hoßfeld, Tobias and Seufert, Michael}, booktitle = {15th International Conference on Quality of Multimedia Experience (QoMEX)}, keywords = {ucn}, month = 6, title = {Explainable Data-Driven QoE Modelling using XAI}, year = 2023 }
Superfrog: Comparing Learning Outcomes and Potentials of a Worksheet, Smartphone, and Tangible AR Learning Environment Oberdörfer, Sebastian; Elsässer, Anne; Grafe, Silke; Latoschik, Marc Erich in 2023 9th International Conference of the Immersive Learning Research Network (iLRN) (2023).
- [ Abstract ]
- [ BibTeX ]
- [ URL ]
The widespread availability of smartphones facilitates the integration of digital, augmented reality (AR), and tangible augmented reality (TAR) learning environments into the classroom. A haptic aspect can enhance the user’s overall experience during a learning process. To investigate further benefits of using TAR for educational purposes, we compare a TAR and a smartphone learning environment with a traditional worksheet counterpart in terms of learning effectiveness, emotions, motivation, and cognitive load. 64 sixth-grade students from a German high school used one of the three conditions to learn about frog anatomy. We found no significant differences in learning effectiveness and cognitive load. The TAR condition elicited significantly higher positive emotions than the worksheet, but not the smartphone condition. Both digital learning environments elicited significantly higher motivation, in contrast to the worksheet. Thus, our results suggest that smartphone and TAR learning environments are equally beneficial for enhancing learning.

@inproceedings{oberdorfer2023comparing, abstract = {The widespread availability of smartphones facilitates the integration of digital, augmented reality (AR), and tangible augmented reality (TAR) learning environments into the classroom. A haptic aspect can enhance the user’s overall experience during a learning process. To investigate further benefits of using TAR for educational purposes, we compare a TAR and a smartphone learning environment with a traditional worksheet counterpart in terms of learning effectiveness, emotions, motivation, and cognitive load. 64 sixth-grade students from a German high school used one of the three conditions to learn about frog anatomy. We found no significant differences in learning effectiveness and cognitive load. The TAR condition elicited significantly higher positive emotions than the worksheet, but not the smartphone condition. Both digital learning environments elicited significantly higher motivation, in contrast to the worksheet. Thus, our results suggest that smartphone and TAR learning environments are equally beneficial for enhancing learning.}, author = {Oberdörfer, Sebastian and Elsässer, Anne and Grafe, Silke and Latoschik, Marc Erich}, booktitle = {2023 9th International Conference of the Immersive Learning Research Network (iLRN)}, keywords = {oberdoerfer}, note = {to be published}, title = {Superfrog: Comparing Learning Outcomes and Potentials of a Worksheet, Smartphone, and Tangible AR Learning Environment}, year = 2023 }
Towards a Computational Analysis of Suspense: Detecting Dangerous Situations Zehe, Albin; Schröter, Julian; Hotho, Andreas (2023).
- [ Abstract ]
- [ BibTeX ]
- [ URL ]
Suspense is an important tool in storytelling to keep readers engaged and wanting to read more. However, it has so far not been studied extensively in Computational Literary Studies. In this paper, we focus on one of the elements authors can use to build up suspense: dangerous situations. We introduce a corpus of texts annotated with dangerous situations, distinguishing between 7 types of danger. Additionally, we annotate parts of the text that describe fear experienced by a character, regardless of the actual presence of danger. We present experiments towards the automatic detection of these situations, finding that unsupervised baseline methods can provide valuable signals for the detection, but more complex methods are necessary for further analysis. Not unexpectedly, the description of danger and fear often relies heavily on the context, both local (e.g., situations where danger is only mentioned, but not actually present) and global (e.g., "storm" being used in a literal sense in an adventure novel, but metaphorically in a romance novel).

@misc{zehe2023towards, abstract = {Suspense is an important tool in storytelling to keep readers engaged and wanting to read more. However, it has so far not been studied extensively in Computational Literary Studies. In this paper, we focus on one of the elements authors can use to build up suspense: dangerous situations. We introduce a corpus of texts annotated with dangerous situations, distinguishing between 7 types of danger. Additionally, we annotate parts of the text that describe fear experienced by a character, regardless of the actual presence of danger. We present experiments towards the automatic detection of these situations, finding that unsupervised baseline methods can provide valuable signals for the detection, but more complex methods are necessary for further analysis. Not unexpectedly, the description of danger and fear often relies heavily on the context, both local (e.g., situations where danger is only mentioned, but not actually present) and global (e.g., "storm" being used in a literal sense in an adventure novel, but metaphorically in a romance novel).}, author = {Zehe, Albin and Schröter, Julian and Hotho, Andreas}, keywords = {word2vec}, note = {cite arxiv:2305.06818 Comment: 4 pages + references & appendix; work in progress}, title = {Towards a Computational Analysis of Suspense: Detecting Dangerous Situations}, year = 2023 }
Serverless Computing Revisited: Evolution, State-of-the-Art, and Performance Challenges Kounev, Samuel (2023).
- [ BibTeX ]
- [ URL ]
@presentation{kounev2023serverless, author = {Kounev, Samuel}, keywords = {myown}, title = {Serverless Computing Revisited: Evolution, State-of-the-Art, and Performance Challenges}, year = 2023 }
Optimizing storage assignment, order picking, and their interaction in mezzanine warehouses Lesch, Veronika; Müller, Patrick B.M.; Krämer, Moritz; Hadry, Marius; Kounev, Samuel; Krupitzer, Christian in Applied intelligence (2023). 25.
- [ BibTeX ]
- [ URL ]
@article{lesch2023optimizing, author = {Lesch, Veronika and Müller, Patrick B.M. and Krämer, Moritz and Hadry, Marius and Kounev, Samuel and Krupitzer, Christian}, journal = {Applied intelligence}, keywords = {myown}, month = {feb}, pages = 25, title = {Optimizing storage assignment, order picking, and their interaction in mezzanine warehouses}, year = 2023 }
Virtual Reality im modernen Englischunterricht und das Potenzial für Inter- und Transkulturelles Lernen - Eine Pilotstudie Hein, Rebecca; Steinbock, Jeanine; Eisenmann, Maria; Latoschik, Marc Erich; Wienrich, Carolin in MedienPädagogik: Zeitschrift für Theorie Und Praxis Der Medienbildung, (M. Mulders; J. Buchner; A. Dengel; R. Zender, eds.) (2023). (51) 191–213.
- [ Abstract ]
- [ BibTeX ]
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Dieser Beitrag präsentiert die Ergebnisse des Seminarkonzepts und der durchgeführten Begleitforschung zum inter- und transkulturellen Lernen in Virtual Reality (VR). Im Rahmen eines Universitätsseminars entwarfen TEFL-Studierende (Teaching English as a Foreign Language) Unterrichtsstunden für fortgeschrittene Lernende des Faches Englisch der gymnasialen Oberstufe, die sich mit der Entwicklung von Empathie und der Fähigkeit zur Perspektivübernahme in interkulturellen Kommunikations- und Austauschsituationen befassten. Der Fokus des Konzepts lag dabei auf dem Verständnis und der Annahme kultureller Gemeinsamkeiten und Unterschiede. Hier werden beispielhaft zwei der erstellten Unterrichtsentwürfe für VR Interventionen vorgestellt und diskutiert. Begleitend zum Seminar wurden empirische Daten erhoben. Zum einen wurde das Potenzial des InteractionSuitcase (eine Sammlung virtueller Objekte) von den Studierenden bewertet. Zum anderen wurde explorativ eine qualitative Methode zur Messung interkultureller Kompetenz (Autobiography of Intercultural Encounters) getestet. Die Ergebnisse dieser explorativen Pilotstudie zeigen, dass die Interaktion mit dem InteractionSuitcase von den Studierenden als intuitiv und gewinnbringend für die Konzeption von Unterrichtskonzepten bewertet wurde. Dennoch integrierten die Studierenden die Manipulation der virtuellen Avatare häufiger im Gegensatz zum InteractionSuitcase in die Unterrichtskonzepte. Der Beitrag verfolgt das Ziel, das Potenzial von VR für inter- und transkulturelles Lernen im gymnasialen Englischunterricht zu identifizieren.

@article{hein2023medienpaed, abstract = {Dieser Beitrag präsentiert die Ergebnisse des Seminarkonzepts und der durchgeführten Begleitforschung zum inter- und transkulturellen Lernen in Virtual Reality (VR). Im Rahmen eines Universitätsseminars entwarfen TEFL-Studierende (Teaching English as a Foreign Language) Unterrichtsstunden für fortgeschrittene Lernende des Faches Englisch der gymnasialen Oberstufe, die sich mit der Entwicklung von Empathie und der Fähigkeit zur Perspektivübernahme in interkulturellen Kommunikations- und Austauschsituationen befassten. Der Fokus des Konzepts lag dabei auf dem Verständnis und der Annahme kultureller Gemeinsamkeiten und Unterschiede. Hier werden beispielhaft zwei der erstellten Unterrichtsentwürfe für VR Interventionen vorgestellt und diskutiert. Begleitend zum Seminar wurden empirische Daten erhoben. Zum einen wurde das Potenzial des InteractionSuitcase (eine Sammlung virtueller Objekte) von den Studierenden bewertet. Zum anderen wurde explorativ eine qualitative Methode zur Messung interkultureller Kompetenz (Autobiography of Intercultural Encounters) getestet. Die Ergebnisse dieser explorativen Pilotstudie zeigen, dass die Interaktion mit dem InteractionSuitcase von den Studierenden als intuitiv und gewinnbringend für die Konzeption von Unterrichtskonzepten bewertet wurde. Dennoch integrierten die Studierenden die Manipulation der virtuellen Avatare häufiger im Gegensatz zum InteractionSuitcase in die Unterrichtskonzepte. Der Beitrag verfolgt das Ziel, das Potenzial von VR für inter- und transkulturelles Lernen im gymnasialen Englischunterricht zu identifizieren.}, author = {Hein, Rebecca and Steinbock, Jeanine and Eisenmann, Maria and Latoschik, Marc Erich and Wienrich, Carolin}, editor = {Mulders, Miriam and Buchner, Josef and Dengel, Andreas and Zender, Raphael}, journal = {MedienPädagogik: Zeitschrift für Theorie Und Praxis Der Medienbildung}, keywords = {rhein}, number = 51, pages = {191-213}, title = {Virtual Reality im modernen Englischunterricht und das Potenzial für Inter- und Transkulturelles Lernen - Eine Pilotstudie}, year = 2023 }
Morphing Planar Graph Drawings Through {3D} Buchin, Kevin; Evans, Will; Frati, Fabrizio; Kostitsyna, Irina; L{\"o}ffler, Maarten; Ophelders, Tim; Wolff, Alexander in Proc. 49th Int. Conf. Current Trends Theory \& Practice Comput. Sci. (SOFSEM’23), Lecture Notes in Computer Science, L. Gąsieniec (ed.) (2023). (Vol. 13878) 80–95.
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@inproceedings{befklow-mpgdt3d-SOFSEM23, author = {Buchin, Kevin and Evans, Will and Frati, Fabrizio and Kostitsyna, Irina and L{\"o}ffler, Maarten and Ophelders, Tim and Wolff, Alexander}, booktitle = {Proc. 49th Int. Conf. Current Trends Theory \& Practice Comput. Sci. (SOFSEM'23)}, editor = {Gąsieniec, Leszek}, keywords = {myown}, pages = {80–95}, publisher = {Springer-Verlag}, series = {Lecture Notes in Computer Science}, title = {Morphing Planar Graph Drawings Through {3D}}, volume = 13878, year = 2023 }
Embodiment and Personalization for Self-Identification with Virtual Humans Fiedler, Marie Luisa; Wolf, Erik; Döllinger, Nina; Botsch, Mario; Latoschik, Marc Erich; Wienrich, Carolin in 2023 IEEE Conference on Virtual Reality and 3D User Interfaces Abstracts and Workshops (VRW) (2023). 799–800.
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Our work investigates the impact of virtual human embodiment and personalization on the sense of embodiment (SoE) and self-identification (SI). We introduce preliminary items to query self-similarity (SS) and self-attribution (SA) with virtual humans as dimensions of SI. In our study, 64 participants successively observed personalized and generic-looking virtual humans, either as embodied avatars in a virtual mirror or as agents while performing tasks. They reported significantly higher SoE and SI when facing personalized virtual humans and significantly higher SoE and SA when facing embodied avatars, indicating that both factors have strong separate and complimentary influence on SoE and SI.

@inproceedings{fiedler2023selfidentification, abstract = {Our work investigates the impact of virtual human embodiment and personalization on the sense of embodiment (SoE) and self-identification (SI). We introduce preliminary items to query self-similarity (SS) and self-attribution (SA) with virtual humans as dimensions of SI. In our study, 64 participants successively observed personalized and generic-looking virtual humans, either as embodied avatars in a virtual mirror or as agents while performing tasks. They reported significantly higher SoE and SI when facing personalized virtual humans and significantly higher SoE and SA when facing embodied avatars, indicating that both factors have strong separate and complimentary influence on SoE and SI.}, author = {Fiedler, Marie Luisa and Wolf, Erik and Döllinger, Nina and Botsch, Mario and Latoschik, Marc Erich and Wienrich, Carolin}, booktitle = {2023 IEEE Conference on Virtual Reality and 3D User Interfaces Abstracts and Workshops (VRW)}, keywords = {vitras}, pages = {799-800}, title = {Embodiment and Personalization for Self-Identification with Virtual Humans}, year = 2023 }
The Impact of Avatar and Environment Congruence on Plausibility, Embodiment, Presence, and the Proteus Effect in Virtual Reality Mal, David; Wolf, Erik; Döllinger, Nina; Wienrich, Carolin; Latoschik, Marc Erich in IEEE Transactions on Visualization and Computer Graphics (2023). 1–11.
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Many studies show the significance of the Proteus effect for serious virtual reality applications. The present study extends the existing knowledge by considering the relationship (congruence) between the self-embodiment (avatar) and the virtual environment. We investigated the impact of avatar and environment types and their congruence on avatar plausibility, sense of embodiment, spatial presence, and the Proteus effect. In a 2 × 2 between-subjects design, participants embodied either an avatar in sports- or business wear in a semantic congruent or incongruent environment while performing lightweight exercises in virtual reality. The avatar-environment congruence significantly affected the avatar’s plausibility but not the sense of embodiment or spatial presence. However, a significant Proteus effect emerged only for participants who reported a high feeling of (virtual) body ownership, indicating that a strong sense of having and owning a virtual body is key to facilitating the Proteus effect. We discuss the results assuming current theories of bottom-up and top-down determinants of the Proteus effect and thus contribute to understanding its underlying mechanisms and determinants.

@article{mal2023impact, abstract = {Many studies show the significance of the Proteus effect for serious virtual reality applications. The present study extends the existing knowledge by considering the relationship (congruence) between the self-embodiment (avatar) and the virtual environment. We investigated the impact of avatar and environment types and their congruence on avatar plausibility, sense of embodiment, spatial presence, and the Proteus effect. In a 2 × 2 between-subjects design, participants embodied either an avatar in sports- or business wear in a semantic congruent or incongruent environment while performing lightweight exercises in virtual reality. The avatar-environment congruence significantly affected the avatar’s plausibility but not the sense of embodiment or spatial presence. However, a significant Proteus effect emerged only for participants who reported a high feeling of (virtual) body ownership, indicating that a strong sense of having and owning a virtual body is key to facilitating the Proteus effect. We discuss the results assuming current theories of bottom-up and top-down determinants of the Proteus effect and thus contribute to understanding its underlying mechanisms and determinants.}, author = {Mal, David and Wolf, Erik and Döllinger, Nina and Wienrich, Carolin and Latoschik, Marc Erich}, journal = {IEEE Transactions on Visualization and Computer Graphics}, keywords = {vitras}, pages = {1-11}, title = {The Impact of Avatar and Environment Congruence on Plausibility, Embodiment, Presence, and the Proteus Effect in Virtual Reality}, year = 2023 }
Measuring Interpersonal Trust towards Virtual Humans with a Virtual Maze Paradigm Lin, Jinghuai; Cronjé, Johrine; Käthner, Ivo; Pauli, Paul; Latoschik, Marc Erich in IEEE Transactions on Visualization and Computer Graphics (TVCG) (2023).
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Virtual humans, including virtual agents and avatars, play an increasingly important role as VR technology advances. For example, virtual humans are used as proxies of users in social VR or as interfaces for AI assistants in online financing. Interpersonal trust is an essential prerequisite in real-life interactions, as well as in the virtual world. However, to date, there are no established interpersonal trust measurement tools specifically for virtual humans in virtual reality. Previously, a virtual maze task was proposed to measure trust towards virtual characters. For the current study, a variant of the paradigm was implemented. The task of the users (the trustors) is to navigate through a maze in virtual reality, where they can interact with a virtual human (the trustee). They can choose to 1) ask for advice and 2) follow advice from the virtual human if they want to. These measures served as behavioural measures of trust. We conducted a validation study with 70 participants in a between-subject design. The two conditions did not differ in the content of the advice but in the appearance, tone of voice and engagement of the trustees (alleged as avatars controlled by other participants). Results indicate that the experimental manipulation was successful, as participants rated the virtual human as more trustworthy in the trustworthy condition than in the untrustworthy condition. Importantly, this manipulation affected the trust behaviour of our participants, who, in the trustworthy condition, asked for advice more often and followed advice more often, indicating that the paradigm is sensitive to assessing interpersonal trust towards virtual humans. Thus, our paradigm can be used to measure differences in interpersonal trust towards virtual humans and may serve as a valuable research tool to investigate trust in virtual reality.

@article{lin2023measuring, abstract = {Virtual humans, including virtual agents and avatars, play an increasingly important role as VR technology advances. For example, virtual humans are used as proxies of users in social VR or as interfaces for AI assistants in online financing. Interpersonal trust is an essential prerequisite in real-life interactions, as well as in the virtual world. However, to date, there are no established interpersonal trust measurement tools specifically for virtual humans in virtual reality. Previously, a virtual maze task was proposed to measure trust towards virtual characters. For the current study, a variant of the paradigm was implemented. The task of the users (the trustors) is to navigate through a maze in virtual reality, where they can interact with a virtual human (the trustee). They can choose to 1) ask for advice and 2) follow advice from the virtual human if they want to. These measures served as behavioural measures of trust. We conducted a validation study with 70 participants in a between-subject design. The two conditions did not differ in the content of the advice but in the appearance, tone of voice and engagement of the trustees (alleged as avatars controlled by other participants). Results indicate that the experimental manipulation was successful, as participants rated the virtual human as more trustworthy in the trustworthy condition than in the untrustworthy condition. Importantly, this manipulation affected the trust behaviour of our participants, who, in the trustworthy condition, asked for advice more often and followed advice more often, indicating that the paradigm is sensitive to assessing interpersonal trust towards virtual humans. Thus, our paradigm can be used to measure differences in interpersonal trust towards virtual humans and may serve as a valuable research tool to investigate trust in virtual reality.}, author = {Lin, Jinghuai and Cronjé, Johrine and Käthner, Ivo and Pauli, Paul and Latoschik, Marc Erich}, journal = {IEEE Transactions on Visualization and Computer Graphics (TVCG)}, keywords = {prima}, note = {IEEE VR Best Paper Honorable Mention 🏆}, title = {Measuring Interpersonal Trust towards Virtual Humans with a Virtual Maze Paradigm}, year = 2023 }
Exploring Plausibility and Presence in Mixed Reality Experiences Westermeier, Franziska; Brübach, Larissa; Latoschik, Marc Erich; Wienrich, Carolin in IEEE Transactions on Visualization and Computer Graphics (TVCG) (2023). 29(5) 2680–2689.
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Mixed Reality (MR) applications along Milgram's Reality-Virtuality (RV) continuum motivated a number of recent theories on potential constructs and factors describing MR experiences. This paper investigates the impact of incongruencies on the sensation/perception and cognition layers to provoke breaks in plausibility, and the effects these breaks have on spatial and overall presence as prominent constructs of Virtual Reality (VR). We developed a simulated maintenance application to test virtual electrical devices. Participants performed test operations on these devices in a counterbalanced, randomized 2x2 between-subject design in either VR as congruent, or Augmented Reality (AR) as incongruent on the sensation/perception layer. Cognitive incongruency was induced by the absence of traceable power outages, decoupling perceived cause and effect after activating potentially defective devices. Our results indicate significant differences in the plausibility ratings between the VR and AR conditions, hence between congruent/incongruent conditions on the sensation/perception layer. In addition, spatial presence revealed a comparable interaction pattern with the VR vs AR conditions. Both factors decreased for the AR condition (incongruent sensation/perception) compared to VR (congruent sensation/perception) for the congruent cognitive case but increased for the incongruent cognitive case. The results are discussed and put into perspective in the scope of recent theories of MR experiences.

@article{westermeier2023exploring, abstract = {Mixed Reality (MR) applications along Milgram's Reality-Virtuality (RV) continuum motivated a number of recent theories on potential constructs and factors describing MR experiences. This paper investigates the impact of incongruencies on the sensation/perception and cognition layers to provoke breaks in plausibility, and the effects these breaks have on spatial and overall presence as prominent constructs of Virtual Reality (VR). We developed a simulated maintenance application to test virtual electrical devices. Participants performed test operations on these devices in a counterbalanced, randomized 2x2 between-subject design in either VR as congruent, or Augmented Reality (AR) as incongruent on the sensation/perception layer. Cognitive incongruency was induced by the absence of traceable power outages, decoupling perceived cause and effect after activating potentially defective devices. Our results indicate significant differences in the plausibility ratings between the VR and AR conditions, hence between congruent/incongruent conditions on the sensation/perception layer. In addition, spatial presence revealed a comparable interaction pattern with the VR vs AR conditions. Both factors decreased for the AR condition (incongruent sensation/perception) compared to VR (congruent sensation/perception) for the congruent cognitive case but increased for the incongruent cognitive case. The results are discussed and put into perspective in the scope of recent theories of MR experiences.}, author = {Westermeier, Franziska and Brübach, Larissa and Latoschik, Marc Erich and Wienrich, Carolin}, journal = {IEEE Transactions on Visualization and Computer Graphics (TVCG)}, keywords = {myown}, month = {may}, note = {IEEE VR Best Paper Nominee 🏆}, number = 5, pages = {2680-2689}, title = {Exploring Plausibility and Presence in Mixed Reality Experiences}, volume = 29, year = 2023 }
Body and Time: Virtual Embodiment and its effect on Time Perception Unruh, Fabian; Vogel, David H.V.; Landeck, Maximilian; Lugrin, Jean-Luc; Latoschik, Marc Erich in IEEE Transactions on Visualization and Computer Graphics (TVCG) (2023).
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This article explores the effect of one’s body representation on time perception. Time Perception is modulated by a variety of factors including, e.g., the current situation or activity, it can display significant disturbances caused by psychological disorders, and it is influenced by emotional and interoceptive states, i.e., ”the sense of the physiological condition of the body”. We investigated this relation between one’s own body and the perception of time in a novel Virtual Reality (VR) experiment explicitly fostering user activity. 36 participants randomly experienced different degrees of embodiment: i) without an avatar (low), ii) with hands (medium), and iii) with a high quality avatar (high). Participants had to repeatedly activate a virtual lamp and estimate the duration of time intervals as well as judge the passage of time. Our results show a significant effect of embodiment on time perception: time passes slower in the low embodiment condition compared to the medium and high conditions. In contrast to prior work, the study provides missing evidence that this effect is independent of the level of activity of participants: In our task users were prompted to repeatedly perform body actions, thereby ruling-out a potential influence of the level of activity. Importantly, duration judgements in both the millisecond and minute ranges seemed unaffected by variations in embodiment. Taken together, these results lead to a better understanding of the relationship between the body and time.

@article{unruh2023virtual, abstract = {This article explores the effect of one’s body representation on time perception. Time Perception is modulated by a variety of factors including, e.g., the current situation or activity, it can display significant disturbances caused by psychological disorders, and it is influenced by emotional and interoceptive states, i.e., ”the sense of the physiological condition of the body”. We investigated this relation between one’s own body and the perception of time in a novel Virtual Reality (VR) experiment explicitly fostering user activity. 36 participants randomly experienced different degrees of embodiment: i) without an avatar (low), ii) with hands (medium), and iii) with a high quality avatar (high). Participants had to repeatedly activate a virtual lamp and estimate the duration of time intervals as well as judge the passage of time. Our results show a significant effect of embodiment on time perception: time passes slower in the low embodiment condition compared to the medium and high conditions. In contrast to prior work, the study provides missing evidence that this effect is independent of the level of activity of participants: In our task users were prompted to repeatedly perform body actions, thereby ruling-out a potential influence of the level of activity. Importantly, duration judgements in both the millisecond and minute ranges seemed unaffected by variations in embodiment. Taken together, these results lead to a better understanding of the relationship between the body and time.}, author = {Unruh, Fabian and Vogel, David H.V. and Landeck, Maximilian and Lugrin, Jean-Luc and Latoschik, Marc Erich}, journal = {IEEE Transactions on Visualization and Computer Graphics (TVCG)}, keywords = {myown}, note = {To be published}, title = {Body and Time: Virtual Embodiment and its effect on Time Perception}, year = 2023 }
Are Embodied Avatars Harmful to our Self-Experience? The Impact of Virtual Embodiment on Body Awareness Döllinger, Nina; Wolf, Erik; Botsch, Mario; Latoschik, Marc Erich; Wienrich, Carolin in CHI Conference on Human Factors in Computing Systems (2023).
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Virtual Reality (VR) allows us to replace our visible body with a virtual self-representation (avatar) and to explore its effects on our body perception. While the feeling of owning and controlling a virtual body is widely researched, how VR affects the awareness of internal body signals (body awareness) remains open. Forty participants performed moving meditation tasks in reality and VR, either facing their mirror image or not. Both the virtual environment and avatars photorealistically matched their real counterparts. We found a negative effect of VR on body awareness, mediated by feeling embodied in and changed by the avatar. Further, we revealed a negative effect of a mirror on body awareness. Our results indicate that assessing body awareness should be essential in evaluating VR designs and avatar embodiment aiming at mental health, as even a scenario as close to reality as possible can distract users from their internal body signals.

@inproceedings{dollinger2023embodied, abstract = {Virtual Reality (VR) allows us to replace our visible body with a virtual self-representation (avatar) and to explore its effects on our body perception. While the feeling of owning and controlling a virtual body is widely researched, how VR affects the awareness of internal body signals (body awareness) remains open. Forty participants performed moving meditation tasks in reality and VR, either facing their mirror image or not. Both the virtual environment and avatars photorealistically matched their real counterparts. We found a negative effect of VR on body awareness, mediated by feeling embodied in and changed by the avatar. Further, we revealed a negative effect of a mirror on body awareness. Our results indicate that assessing body awareness should be essential in evaluating VR designs and avatar embodiment aiming at mental health, as even a scenario as close to reality as possible can distract users from their internal body signals.}, author = {Döllinger, Nina and Wolf, Erik and Botsch, Mario and Latoschik, Marc Erich and Wienrich, Carolin}, booktitle = {CHI Conference on Human Factors in Computing Systems}, keywords = {vitras}, note = {Honorable Mention 🏆}, publisher = {Association for Computing Machinery}, title = {Are Embodied Avatars Harmful to our Self-Experience? The Impact of Virtual Embodiment on Body Awareness}, year = 2023 }
Moving Down the Stack: Performance Evaluation of Packet Processing Technologies for Stateful Firewalls Dietz, Katharina; Gray, Nicholas; Wolz, Manuel; Lorenz, Claas; Hoßfeld, Tobias; Seufert, Michael in 34th IEEE/IFIP Network Operations and Management Symposium (NOMS) (2023).
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@inproceedings{info3-inproceedings-2023-2, address = {Miami, Florida}, author = {Dietz, Katharina and Gray, Nicholas and Wolz, Manuel and Lorenz, Claas and Hoßfeld, Tobias and Seufert, Michael}, booktitle = {34th IEEE/IFIP Network Operations and Management Symposium (NOMS)}, keywords = {ucn}, month = 5, title = {Moving Down the Stack: Performance Evaluation of Packet Processing Technologies for Stateful Firewalls}, year = 2023 }
A Subjective Quality Assessment of Temporally Reprojected Specular Reflections in Virtual Reality Mišiak, Martin; Fuhrmann, Arnulph; Latoschik, Marc Erich in 2023 IEEE Conference on Virtual Reality and 3D User Interfaces Abstracts and Workshops (VRW) (2023). 1–2.
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Temporal reprojection is a popular method for mitigating sampling artifacts from a variety of sources. This work investigates it's impact on the subjective quality of specular reflections in Virtual Reality(VR). Our results show that temporal reprojection is highly effective at improving the visual comfort of specular materials, especially at low sample counts. A slightly diminished effect could also be observed in improving the subjective accuracy of the resulting reflection.

@inproceedings{misiak2023subjective, abstract = {Temporal reprojection is a popular method for mitigating sampling artifacts from a variety of sources. This work investigates it's impact on the subjective quality of specular reflections in Virtual Reality(VR). Our results show that temporal reprojection is highly effective at improving the visual comfort of specular materials, especially at low sample counts. A slightly diminished effect could also be observed in improving the subjective accuracy of the resulting reflection.}, author = {Mišiak, Martin and Fuhrmann, Arnulph and Latoschik, Marc Erich}, booktitle = {2023 IEEE Conference on Virtual Reality and 3D User Interfaces Abstracts and Workshops (VRW)}, keywords = {myown}, note = {To be published}, pages = {1–2}, title = {A Subjective Quality Assessment of Temporally Reprojected Specular Reflections in Virtual Reality}, year = 2023 }
Discrete-Time Analysis of Multi-Component Queuing Networks under Renewal Approximation Geißler, Stefan; Lange, Stanislav; Hasslinger, Gerhard; Tran-Gia, Phuoc; Hoßfeld, Tobias in 34th International Teletraffic Congress (ITC). Shenzhen, China (2023).
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@inproceedings{info3-inproceedings-2023-1, author = {Geißler, Stefan and Lange, Stanislav and Hasslinger, Gerhard and Tran-Gia, Phuoc and Hoßfeld, Tobias}, booktitle = {34th International Teletraffic Congress (ITC). Shenzhen, China}, keywords = {myown}, month = 9, title = {Discrete-Time Analysis of Multi-Component Queuing Networks under Renewal Approximation}, year = 2023 }
Parameterized Approaches to Orthogonal Compaction Didimo, Walter; Gupta, Siddharth; Kindermann, Philipp; Liotta, Giuseppe; Wolff, Alexander; Zehavi, Meirav in Proc. 49th Int. Conf. Current Trends Theory \& Practice Comput. Sci. (SOFSEM’23), Lecture Notes in Computer Science, L. Gąsieniec (ed.) (2023). (Vol. 13878) 111–128.
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@inproceedings{dgklwz-paoc-SOFSEM23, author = {Didimo, Walter and Gupta, Siddharth and Kindermann, Philipp and Liotta, Giuseppe and Wolff, Alexander and Zehavi, Meirav}, booktitle = {Proc. 49th Int. Conf. Current Trends Theory \& Practice Comput. Sci. (SOFSEM'23)}, editor = {Gąsieniec, Leszek}, keywords = {myown}, pages = {111–128}, publisher = {Springer-Verlag}, series = {Lecture Notes in Computer Science}, title = {Parameterized Approaches to Orthogonal Compaction}, volume = 13878, year = 2023 }
The Complexity of Finding Tangles Firman, Oksana; Kindermann, Philipp; Ravsky, Alexander; Wolff, Alexander; Zink, Johannes in Proc. 49th Int. Conf. Current Trends Theory \& Practice Comput. Sci. (SOFSEM’23), Lecture Notes in Computer Science, L. Gąsieniec (ed.) (2023). (Vol. 13878) 3–17.
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@inproceedings{ffkrwz-cotf-SOFSEM23, author = {Firman, Oksana and Kindermann, Philipp and Ravsky, Alexander and Wolff, Alexander and Zink, Johannes}, booktitle = {Proc. 49th Int. Conf. Current Trends Theory \& Practice Comput. Sci. (SOFSEM'23)}, editor = {Gąsieniec, Leszek}, keywords = {myown}, pages = {3–17}, publisher = {Springer-Verlag}, series = {Lecture Notes in Computer Science}, title = {The Complexity of Finding Tangles}, volume = 13878, year = 2023 }
Outside-Obstacle Representations with All Vertices on the Outer Face Firman, Oksana; Kindermann, Philipp; Klawitter, Jonathan; Klemz, Boris; Klesen, Felix; Wolff, Alexander in Proc. 30th Int. Symp. Graph Drawing \& Network Vis. (GD’22), Lecture Notes in Computer Science, P. Angelini, R. von Hanxleden (eds.) (2023). (Vol. 13764) 432–440.
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@inproceedings{fkkkkw-ooravof-GD22, author = {Firman, Oksana and Kindermann, Philipp and Klawitter, Jonathan and Klemz, Boris and Klesen, Felix and Wolff, Alexander}, booktitle = {Proc. 30th Int. Symp. Graph Drawing \& Network Vis. (GD'22)}, editor = {Angelini, Patrizio and von Hanxleden, Reinhard}, keywords = {myown}, pages = {432–440}, publisher = {Springer-Verlag}, series = {Lecture Notes in Computer Science}, title = {Outside-Obstacle Representations with All Vertices on the Outer Face}, volume = 13764, year = 2023 }
Coloring Mixed and Directional Interval Graphs Gutowski, Grzegorz; Mittelst{\"a}dt, Florian; Rutter, Ignaz; Spoerhase, Joachim; Wolff, Alexander; Zink, Johannes in Proc. 30th Int. Symp. Graph Drawing \& Network Vis. (GD’22), Lecture Notes in Computer Science, P. Angelini, R. von Hanxleden (eds.) (2023). (Vol. 13764) 418–431.
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@inproceedings{gmrswz-cmdig-GD22, author = {Gutowski, Grzegorz and Mittelst{\"a}dt, Florian and Rutter, Ignaz and Spoerhase, Joachim and Wolff, Alexander and Zink, Johannes}, booktitle = {Proc. 30th Int. Symp. Graph Drawing \& Network Vis. (GD'22)}, editor = {Angelini, Patrizio and von Hanxleden, Reinhard}, keywords = {myown}, pages = {418–431}, publisher = {Springer-Verlag}, series = {Lecture Notes in Computer Science}, title = {Coloring Mixed and Directional Interval Graphs}, volume = 13764, year = 2023 }
Visualizing Multispecies Coalescent Trees: Drawing Gene Trees Inside Species Trees Klawitter, Jonathan; Klesen, Felix; Niederer, Moritz; Wolff, Alexander in Proc. 49th Int. Conf. Current Trends Theory \& Practice Comput. Sci. (SOFSEM’23), Lecture Notes in Computer Science, L. Gąsieniec (ed.) (2023). (Vol. 13878) 96–110.
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@inproceedings{kknw-vmct-SOFSEM23, author = {Klawitter, Jonathan and Klesen, Felix and Niederer, Moritz and Wolff, Alexander}, booktitle = {Proc. 49th Int. Conf. Current Trends Theory \& Practice Comput. Sci. (SOFSEM'23)}, editor = {Gąsieniec, Leszek}, keywords = {myown}, pages = {96–110}, publisher = {Springer-Verlag}, series = {Lecture Notes in Computer Science}, title = {Visualizing Multispecies Coalescent Trees: Drawing Gene Trees Inside Species Trees}, volume = 13878, year = 2023 }
Usability of a {{Mhealth Solution}} Using {{Speech Recognition}} for {{Point-of-care Diagnostic Management}} Kerwagen, Fabian; Fuchs, Konrad F.; Ullrich, Melanie; Schulze, Andreas; Straka, Samantha; Krop, Philipp; Latoschik, Marc E.; Gilbert, Fabian; Kunz, Andreas; Fette, Georg; St{\"o}rk, Stefan; Ertl, Maximilian in Journal of Medical Systems (2023). 47(18)
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The administrative burden for physicians in the hospital can affect the quality of patient care. The Service Center Medical Informatics (SMI) of the University Hospital W\"urzburg developed and implemented the smartphone-based mobile application (MA) ukw.mobile1 that uses speech recognition for the point-of-care ordering of radiological examinations. The aim of this study was to examine the usability of the MA workflow for the point-of-care ordering of radiological examinations. All physicians at the Department of Trauma and Plastic Surgery at the University Hospital W\"urzburg, Germany, were asked to participate in a survey including the short version of the User Experience Questionnaire (UEQ-S) and the Unified Theory of Acceptance and Use of Technology (UTAUT). For the analysis of the different domains of user experience (overall attractiveness, pragmatic quality and hedonic quality), we used a two-sided dependent sample t-test. For the determinants of the acceptance model, we employed regression analysis. Twenty-one of 30 physicians (mean age 34\,{$\pm$}\,8 years, 62\% male) completed the questionnaire. Compared to the conventional desktop application (DA) workflow, the new MA workflow showed superior overall attractiveness (mean difference 2.15\,{$\pm$}\,1.33), pragmatic quality (mean difference 1.90\,{$\pm$}\,1.16), and hedonic quality (mean difference 2.41\,{$\pm$}\,1.62; all p\,{$<$}\,.001). The user acceptance measured by the UTAUT (mean 4.49\,{$\pm$}\,0.41; min. 1, max. 5) was also high. Performance expectancy (beta\,=\,0.57, p\,=\,.02) and effort expectancy (beta\,=\,0.36, p\,=\,.04) were identified as predictors of acceptance, the full predictive model explained 65.4\% of the variance. Point-of-care mHealth solutions using innovative technology such as speech-recognition seem to address the users' needs and to offer higher usability in comparison to conventional technology. Implementation of user-centered mHealth innovations might therefore help to facilitate physicians' daily work.

@article{kerwagen2023, abstract = {The administrative burden for physicians in the hospital can affect the quality of patient care. The Service Center Medical Informatics (SMI) of the University Hospital W\"urzburg developed and implemented the smartphone-based mobile application (MA) ukw.mobile1 that uses speech recognition for the point-of-care ordering of radiological examinations. The aim of this study was to examine the usability of the MA workflow for the point-of-care ordering of radiological examinations. All physicians at the Department of Trauma and Plastic Surgery at the University Hospital W\"urzburg, Germany, were asked to participate in a survey including the short version of the User Experience Questionnaire (UEQ-S) and the Unified Theory of Acceptance and Use of Technology (UTAUT). For the analysis of the different domains of user experience (overall attractiveness, pragmatic quality and hedonic quality), we used a two-sided dependent sample t-test. For the determinants of the acceptance model, we employed regression analysis. Twenty-one of 30 physicians (mean age 34\,{$\pm$}\,8 years, 62\% male) completed the questionnaire. Compared to the conventional desktop application (DA) workflow, the new MA workflow showed superior overall attractiveness (mean difference 2.15\,{$\pm$}\,1.33), pragmatic quality (mean difference 1.90\,{$\pm$}\,1.16), and hedonic quality (mean difference 2.41\,{$\pm$}\,1.62; all p\,{$<$}\,.001). The user acceptance measured by the UTAUT (mean 4.49\,{$\pm$}\,0.41; min. 1, max. 5) was also high. Performance expectancy (beta\,=\,0.57, p\,=\,.02) and effort expectancy (beta\,=\,0.36, p\,=\,.04) were identified as predictors of acceptance, the full predictive model explained 65.4\% of the variance. Point-of-care mHealth solutions using innovative technology such as speech-recognition seem to address the users' needs and to offer higher usability in comparison to conventional technology. Implementation of user-centered mHealth innovations might therefore help to facilitate physicians' daily work.}, author = {Kerwagen, Fabian and Fuchs, Konrad F. and Ullrich, Melanie and Schulze, Andreas and Straka, Samantha and Krop, Philipp and Latoschik, Marc E. and Gilbert, Fabian and Kunz, Andreas and Fette, Georg and St{\"o}rk, Stefan and Ertl, Maximilian}, journal = {Journal of Medical Systems}, keywords = {myown}, number = 18, title = {Usability of a {{Mhealth Solution}} Using {{Speech Recognition}} for {{Point-of-care Diagnostic Management}}}, volume = 47, year = 2023 }
A Systematic Approach for Benchmarking of Container Orchestration Frameworks Straesser, Martin; Mathiasch, Jonas; Bauer, Andr\’{e}; Kounev, Samuel in Proceedings of the 2023 ACM/SPEC International Conference on Performance Engineering, ICPE ’23 (2023). 187–198.
- [ Abstract ]
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Container orchestration frameworks play a critical role in modern cloud computing paradigms such as cloud-native or serverless computing. They significantly impact the quality and cost of service deployment as they manage many performance-critical tasks such as container provisioning, scheduling, scaling, and networking. Consequently, a comprehensive performance assessment of container orchestration frameworks is essential. However, until now, there is no benchmarking approach that covers the many different tasks implemented in such platforms and supports evaluating different technology stacks. In this paper, we present a systematic approach that enables benchmarking of container orchestrators. Based on a definition of container orchestration, we define the core requirements and benchmarking scope for such platforms. Each requirement is then linked to metrics and measurement methods, and a benchmark architecture is proposed. With COFFEE, we introduce a benchmarking tool supporting the definition of complex test campaigns for container orchestration frameworks. We demonstrate the potential of our approach with case studies of the frameworks Kubernetes and Nomad in a self-hosted environment and on the Google Cloud Platform. The presented case studies focus on container startup times, crash recovery, rolling updates, and more.

@inproceedings{straesser2023orchestration, abstract = {Container orchestration frameworks play a critical role in modern cloud computing paradigms such as cloud-native or serverless computing. They significantly impact the quality and cost of service deployment as they manage many performance-critical tasks such as container provisioning, scheduling, scaling, and networking. Consequently, a comprehensive performance assessment of container orchestration frameworks is essential. However, until now, there is no benchmarking approach that covers the many different tasks implemented in such platforms and supports evaluating different technology stacks. In this paper, we present a systematic approach that enables benchmarking of container orchestrators. Based on a definition of container orchestration, we define the core requirements and benchmarking scope for such platforms. Each requirement is then linked to metrics and measurement methods, and a benchmark architecture is proposed. With COFFEE, we introduce a benchmarking tool supporting the definition of complex test campaigns for container orchestration frameworks. We demonstrate the potential of our approach with case studies of the frameworks Kubernetes and Nomad in a self-hosted environment and on the Google Cloud Platform. The presented case studies focus on container startup times, crash recovery, rolling updates, and more.}, address = {New York, NY, USA}, author = {Straesser, Martin and Mathiasch, Jonas and Bauer, Andr\'{e} and Kounev, Samuel}, booktitle = {Proceedings of the 2023 ACM/SPEC International Conference on Performance Engineering}, keywords = {myown}, pages = {187-198}, publisher = {Association for Computing Machinery}, series = {ICPE '23}, title = {A Systematic Approach for Benchmarking of Container Orchestration Frameworks}, year = 2023 }
Segmentierung und Verlaufskontrolle chronischer Wunden durch künstliche Intelligenz mithilfe einer mobilen App (WUNDERKINT Studie) Borst, Vanessa; Dege, Tassilo; Grän, Franziska; Hamrouni, Sandra; Michel, Daniel; Hager, Valerie; Goebeler, Matthias; Leppich, Robert; Kounev, Samuel; Schmieder, Astrid in Allergologie. JDDG: Journal der Deutschen Dermatologischen Gesellschaft (2023). (Vol. 21) 28–177.
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@incollection{borst_ddg23_v2, author = {Borst, Vanessa and Dege, Tassilo and Grän, Franziska and Hamrouni, Sandra and Michel, Daniel and Hager, Valerie and Goebeler, Matthias and Leppich, Robert and Kounev, Samuel and Schmieder, Astrid}, booktitle = {Allergologie. JDDG: Journal der Deutschen Dermatologischen Gesellschaft}, keywords = {myown}, month = {April}, note = {Poster Abstract (No. P322, pp. 175-176)}, number = {S1}, pages = {28-177}, publisher = {John Wiley & Sons Ltd.}, title = {Segmentierung und Verlaufskontrolle chronischer Wunden durch künstliche Intelligenz mithilfe einer mobilen App (WUNDERKINT Studie)}, volume = 21, year = 2023 }
An Approach to Investigate an Influence of Visual Angle Size on Emotional Activation During a Decision-Making Task Oberdörfer, Sebastian; Birnstiel, Sandra; Steinhaeusser, Sophia C.; Latoschik, Marc Erich in HCII 2023, Lecture Notes in Computer Science (2023).
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Decision-making is an important ability in our daily lives. Decision-making can be influenced by emotions. A virtual environment and objects in it might follow an emotional design, thus potentially influ- encing the mood of a user. A higher visual angle on a particular stimulus can lead to a higher emotional response to it. The use of immersive vir- tual reality (VR) surrounds a user visually with a virtual environment, as opposed to the partial immersion of using a normal computer screen. This higher immersion may result in a greater visual angle on a particu- lar stimulus and thus a stronger emotional response to it. In a between- subjects user study, we compare the results of a decision-making task in VR presented in three different visual angles. We used the Iowa Gambling Task (IGT) as task and to detect potential differences in decision-making. The IGT was displayed in one of three dimensions, thus yielding visual angles of 20◦, 35◦, and 50◦. Our results indicate no difference between the three conditions with respect to decision-making. Thus, our results possibly imply that a higher visual angle has no influence on a task that is influenced by emotions but is otherwise cognitive.

@inproceedings{oberdorfer2023approach, abstract = {Decision-making is an important ability in our daily lives. Decision-making can be influenced by emotions. A virtual environment and objects in it might follow an emotional design, thus potentially influ- encing the mood of a user. A higher visual angle on a particular stimulus can lead to a higher emotional response to it. The use of immersive vir- tual reality (VR) surrounds a user visually with a virtual environment, as opposed to the partial immersion of using a normal computer screen. This higher immersion may result in a greater visual angle on a particu- lar stimulus and thus a stronger emotional response to it. In a between- subjects user study, we compare the results of a decision-making task in VR presented in three different visual angles. We used the Iowa Gambling Task (IGT) as task and to detect potential differences in decision-making. The IGT was displayed in one of three dimensions, thus yielding visual angles of 20◦, 35◦, and 50◦. Our results indicate no difference between the three conditions with respect to decision-making. Thus, our results possibly imply that a higher visual angle has no influence on a task that is influenced by emotions but is otherwise cognitive.}, author = {Oberdörfer, Sebastian and Birnstiel, Sandra and Steinhaeusser, Sophia C. and Latoschik, Marc Erich}, booktitle = {HCII 2023}, keywords = {steinhaeusser}, note = {to be published}, publisher = {Springer, Cham}, series = {Lecture Notes in Computer Science}, title = {An Approach to Investigate an Influence of Visual Angle Size on Emotional Activation During a Decision-Making Task}, year = 2023 }
Power to the Applications: The Vision of Continuous Decentralized Autoscaling Straesser, Martin; Geißler, Stefan; Hoßfeld, Tobias; Kounev, Samuel in 2023 IEEE/ACM 23rd International Symposium on Cluster, Cloud and Internet Computing Workshops (CCGridW) (2023).
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@inproceedings{straesser2023decentral, author = {Straesser, Martin and Geißler, Stefan and Hoßfeld, Tobias and Kounev, Samuel}, booktitle = {2023 IEEE/ACM 23rd International Symposium on Cluster, Cloud and Internet Computing Workshops (CCGridW)}, keywords = {myown}, note = {In print.}, publisher = {IEEE}, title = {Power to the Applications: The Vision of Continuous Decentralized Autoscaling}, year = 2023 }
Power to the Applications: The Vision of Continuous Decentralized Autoscaling Straesser, Martin; Geißler, Stefan; Hoßfeld, Tobias; Kounev, Samuel in 2023 IEEE/ACM 23rd International Symposium on Cluster, Cloud and Internet Computing Workshops (CCGridW) (2023).
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@inproceedings{straesser2023decentral, author = {Straesser, Martin and Geißler, Stefan and Hoßfeld, Tobias and Kounev, Samuel}, booktitle = {2023 IEEE/ACM 23rd International Symposium on Cluster, Cloud and Internet Computing Workshops (CCGridW)}, keywords = {myown}, note = {In print.}, publisher = {IEEE}, title = {Power to the Applications: The Vision of Continuous Decentralized Autoscaling}, year = 2023 }
The NarRobot Plugin - Connecting the Social Robot Reeti to the Unity Game Engine Steinhaeusser, Sophia C.; Siol, Lenny; Ganal, Elisabeth; Maier, Sophia; Lugrin, Birgit in Companion of the 2023 ACM/IEEE International Conference on Human-Robot Interaction (HRI) (2023).
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@inproceedings{steinhaeusser2023narrobot, author = {Steinhaeusser, Sophia C. and Siol, Lenny and Ganal, Elisabeth and Maier, Sophia and Lugrin, Birgit}, booktitle = {Companion of the 2023 ACM/IEEE International Conference on Human-Robot Interaction (HRI)}, keywords = {steinhaeusser}, title = {The NarRobot Plugin - Connecting the Social Robot Reeti to the Unity Game Engine}, year = 2023 }
Using a Social Robot as a Hotel Assessment Tool Lein, Martina; Donnermann, Melissa; Steinhaeusser, Sophia C.; Lugrin, Birgit in Companion of the 2023 ACM/IEEE International Conference on Human-Robot Interaction (HRI) (2023).
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@inproceedings{lein2023, author = {Lein, Martina and Donnermann, Melissa and Steinhaeusser, Sophia C. and Lugrin, Birgit}, booktitle = {Companion of the 2023 ACM/IEEE International Conference on Human-Robot Interaction (HRI)}, keywords = {steinhaeusser}, title = {Using a Social Robot as a Hotel Assessment Tool}, year = 2023 }
A literature review of IoT and CPS—What they are, and what they are not Lesch, Veronika; Z{\"u}fle, Marwin; Bauer, Andr{\’e}; Iffl{\"a}nder, Lukas; Krupitzer, Christian; Kounev, Samuel in Journal of Systems and Software (2023). 111631.
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Today, we are confronted with many concepts such as Cyber–Physical-Systems (CPS), Internet of Things (IoT), Industry 4.0, Industrial Internet, Ubiquitous Computing, Pervasive Computing and many more. Some researchers use all of these terms interchangeably, while others interpret them in ways that contradict each other. The inconsistent and interchangeable usage of these terms creates the impression that authors abuse them as buzzwords to attract attention. Hence, the question arises: Is the existence of all these terms justified? In this paper, we first look at the origin of the terms. Then, we focus on Internet of Things (IoT) and Cyber-Physical-Systems (CPS) as those terms are more often used as the others and further often seen as underlying technologies. We presentthe results of a literature review, including academic, industry and gray literature, with the objective to identify and discuss several clusters of similar statements on both terms. Building on this, we present definitions for IoT and CPS that reflect the core intuition of the terms as found in the literature review while providing a clear demarcation of the two terms. Then, we illustrate the applicability of our findings on several use cases. Finally, we discuss the relation to the other topics closely related to adaptive systems, namely Industry 4.0, Industrial Internet, Ubiquitous Computing, and Pervasive Computing.

@article{lesch2023literature, abstract = {Today, we are confronted with many concepts such as Cyber–Physical-Systems (CPS), Internet of Things (IoT), Industry 4.0, Industrial Internet, Ubiquitous Computing, Pervasive Computing and many more. Some researchers use all of these terms interchangeably, while others interpret them in ways that contradict each other. The inconsistent and interchangeable usage of these terms creates the impression that authors abuse them as buzzwords to attract attention. Hence, the question arises: Is the existence of all these terms justified? In this paper, we first look at the origin of the terms. Then, we focus on Internet of Things (IoT) and Cyber-Physical-Systems (CPS) as those terms are more often used as the others and further often seen as underlying technologies. We presentthe results of a literature review, including academic, industry and gray literature, with the objective to identify and discuss several clusters of similar statements on both terms. Building on this, we present definitions for IoT and CPS that reflect the core intuition of the terms as found in the literature review while providing a clear demarcation of the two terms. Then, we illustrate the applicability of our findings on several use cases. Finally, we discuss the relation to the other topics closely related to adaptive systems, namely Industry 4.0, Industrial Internet, Ubiquitous Computing, and Pervasive Computing.}, author = {Lesch, Veronika and Z{\"u}fle, Marwin and Bauer, Andr{\'e} and Iffl{\"a}nder, Lukas and Krupitzer, Christian and Kounev, Samuel}, journal = {Journal of Systems and Software}, keywords = {myown}, pages = 111631, publisher = {Elsevier}, title = {A literature review of IoT and CPS—What they are, and what they are not}, year = 2023 }
Text Input for Non-Stationary XR Workspaces: Investigating Tap and Word-Gesture Keyboards in Virtual and Augmented Reality Kern, Florian; Niebling, Florian; Latoschik, Marc Erich in IEEE Transactions on Visualization and Computer Graphics (2023). 1–12.
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This article compares two state-of-the-art text input techniques between non-stationary virtual reality (VR) and video see-through augmented reality (VST AR) use-cases as XR display condition. The developed contact-based mid-air virtual tap and wordgesture (swipe) keyboard provide established support functions for text correction, word suggestions, capitalization, and punctuation. A user evaluation with 64 participants revealed that XR displays and input techniques strongly affect text entry performance, while subjective measures are only influenced by the input techniques. We found significantly higher usability and user experience ratings for tap keyboards compared to swipe keyboards in both VR and VST AR. Task load was also lower for tap keyboards. In terms of performance, both input techniques were significantly faster in VR than in VST AR. Further, the tap keyboard was significantly faster than the swipe keyboard in VR. Participants showed a significant learning effect with only ten sentences typed per condition. Our results are consistent with previous work in VR and optical see-through (OST) AR, but additionally provide novel insights into usability and performance of the selected text input techniques for VST AR. The significant differences in subjective and objective measures emphasize the importance of specific evaluations for each possible combination of input techniques and XR displays to provide reusable, reliable, and high-quality text input solutions. With our work, we form a foundation for future research and XR workspaces. Our reference implementation is publicly available to encourage replicability and reuse in future XR workspaces.

@article{kern2023input, abstract = {This article compares two state-of-the-art text input techniques between non-stationary virtual reality (VR) and video see-through augmented reality (VST AR) use-cases as XR display condition. The developed contact-based mid-air virtual tap and wordgesture (swipe) keyboard provide established support functions for text correction, word suggestions, capitalization, and punctuation. A user evaluation with 64 participants revealed that XR displays and input techniques strongly affect text entry performance, while subjective measures are only influenced by the input techniques. We found significantly higher usability and user experience ratings for tap keyboards compared to swipe keyboards in both VR and VST AR. Task load was also lower for tap keyboards. In terms of performance, both input techniques were significantly faster in VR than in VST AR. Further, the tap keyboard was significantly faster than the swipe keyboard in VR. Participants showed a significant learning effect with only ten sentences typed per condition. Our results are consistent with previous work in VR and optical see-through (OST) AR, but additionally provide novel insights into usability and performance of the selected text input techniques for VST AR. The significant differences in subjective and objective measures emphasize the importance of specific evaluations for each possible combination of input techniques and XR displays to provide reusable, reliable, and high-quality text input solutions. With our work, we form a foundation for future research and XR workspaces. Our reference implementation is publicly available to encourage replicability and reuse in future XR workspaces.}, author = {Kern, Florian and Niebling, Florian and Latoschik, Marc Erich}, journal = {IEEE Transactions on Visualization and Computer Graphics}, keywords = {myown}, pages = {1-12}, title = {Text Input for Non-Stationary XR Workspaces: Investigating Tap and Word-Gesture Keyboards in Virtual and Augmented Reality}, year = 2023 }
Extensible Motion-based Identification of XR Users with Non-Specific Motion Schell, Christian; Kobs, Konstantin; Fernando, Tamara; Hotho, Andreas; Latoschik, Marc Erich (2023, March). arXiv:2302.07517.
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Recently emerged solutions demonstrate that the movements of users interacting with extended reality (XR) applications carry identifying information and can be leveraged for identification. While such solutions can identify XR users within a few seconds, current systems require one or the other trade-off: either they apply simple distance-based approaches that can only be used for specific predetermined motions. Or they use classification-based approaches that use more powerful machine learning models and thus also work for arbitrary motions, but require full retraining to enroll new users, which can be prohibitively expensive. In this paper, we propose to combine the strengths of both approaches by using an embedding-based approach that leverages deep metric learning. We train the model on a dataset of users playing the VR game "Half-Life: Alyx" and conduct multiple experiments and analyses. The results show that the embedding-based method 1) is able to identify new users from non-specific movements using only a few minutes of reference data, 2) can enroll new users within seconds, while retraining a comparable classification-based approach takes almost a day, 3) is more reliable than a baseline classification-based approach when only little reference data is available, 4) can be used to identify new users from another dataset recorded with different VR devices. Altogether, our solution is a foundation for easily extensible XR user identification systems, applicable even to non-specific movements. It also paves the way for production-ready models that could be used by XR practitioners without the requirements of expertise, hardware, or data for training deep learning models.

@preprint{2023arXiv230207517S, abstract = {Recently emerged solutions demonstrate that the movements of users interacting with extended reality (XR) applications carry identifying information and can be leveraged for identification. While such solutions can identify XR users within a few seconds, current systems require one or the other trade-off: either they apply simple distance-based approaches that can only be used for specific predetermined motions. Or they use classification-based approaches that use more powerful machine learning models and thus also work for arbitrary motions, but require full retraining to enroll new users, which can be prohibitively expensive. In this paper, we propose to combine the strengths of both approaches by using an embedding-based approach that leverages deep metric learning. We train the model on a dataset of users playing the VR game "Half-Life: Alyx" and conduct multiple experiments and analyses. The results show that the embedding-based method 1) is able to identify new users from non-specific movements using only a few minutes of reference data, 2) can enroll new users within seconds, while retraining a comparable classification-based approach takes almost a day, 3) is more reliable than a baseline classification-based approach when only little reference data is available, 4) can be used to identify new users from another dataset recorded with different VR devices. Altogether, our solution is a foundation for easily extensible XR user identification systems, applicable even to non-specific movements. It also paves the way for production-ready models that could be used by XR practitioners without the requirements of expertise, hardware, or data for training deep learning models.}, author = {Schell, Christian and Kobs, Konstantin and Fernando, Tamara and Hotho, Andreas and Latoschik, Marc Erich}, journal = {arXiv}, keywords = {prima}, month = {feb}, pages = {arXiv:2302.07517}, title = {Extensible Motion-based Identification of XR Users with Non-Specific Motion}, year = 2023 }
Optimizing storage assignment, order picking, and their interaction in mezzanine warehouses Lesch, Veronika; Müller, Patrick B.M.; Krämer, Moritz; Hadry, Marius; Kounev, Samuel; Krupitzer, Christian in Applied intelligence (2023). 25.
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@article{lesch2023optimizing, author = {Lesch, Veronika and Müller, Patrick B.M. and Krämer, Moritz and Hadry, Marius and Kounev, Samuel and Krupitzer, Christian}, journal = {Applied intelligence}, keywords = {myown}, month = {feb}, pages = 25, title = {Optimizing storage assignment, order picking, and their interaction in mezzanine warehouses}, year = 2023 }
Autoscaler Evaluation and Configuration: A Practitioner’s Guideline Straesser, Martin; Eismann, Simon; von Kistowski, J\’{o}akim; Bauer, Andr\’{e}; Kounev, Samuel in Proceedings of the 2023 ACM/SPEC International Conference on Performance Engineering, ICPE ’23 (2023).
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@inproceedings{straesser2023guideline, address = {New York, NY, USA}, author = {Straesser, Martin and Eismann, Simon and von Kistowski, J\'{o}akim and Bauer, Andr\'{e} and Kounev, Samuel}, booktitle = {Proceedings of the 2023 ACM/SPEC International Conference on Performance Engineering}, keywords = {myown}, note = {In print.}, publisher = {Association for Computing Machinery}, series = {ICPE '23}, title = {Autoscaler Evaluation and Configuration: A Practitioner's Guideline}, year = 2023 }
Autoscaler Evaluation and Configuration: A Practitioner’s Guideline Straesser, Martin; Eismann, Simon; von Kistowski, J\’{o}akim; Bauer, Andr\’{e}; Kounev, Samuel in Proceedings of the 2023 ACM/SPEC International Conference on Performance Engineering, ICPE ’23 (2023).
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@inproceedings{straesser2023guideline, address = {New York, NY, USA}, author = {Straesser, Martin and Eismann, Simon and von Kistowski, J\'{o}akim and Bauer, Andr\'{e} and Kounev, Samuel}, booktitle = {Proceedings of the 2023 ACM/SPEC International Conference on Performance Engineering}, keywords = {myown}, note = {In print.}, publisher = {Association for Computing Machinery}, series = {ICPE '23}, title = {Autoscaler Evaluation and Configuration: A Practitioner's Guideline}, year = 2023 }
A Systematic Approach for Benchmarking of Container Orchestration Frameworks Straesser, Martin; Mathiasch, Jonas; Bauer, Andr\’{e}; Kounev, Samuel in Proceedings of the 2023 ACM/SPEC International Conference on Performance Engineering, ICPE ’23 (2023). 187–198.
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- [ URL ]
Container orchestration frameworks play a critical role in modern cloud computing paradigms such as cloud-native or serverless computing. They significantly impact the quality and cost of service deployment as they manage many performance-critical tasks such as container provisioning, scheduling, scaling, and networking. Consequently, a comprehensive performance assessment of container orchestration frameworks is essential. However, until now, there is no benchmarking approach that covers the many different tasks implemented in such platforms and supports evaluating different technology stacks. In this paper, we present a systematic approach that enables benchmarking of container orchestrators. Based on a definition of container orchestration, we define the core requirements and benchmarking scope for such platforms. Each requirement is then linked to metrics and measurement methods, and a benchmark architecture is proposed. With COFFEE, we introduce a benchmarking tool supporting the definition of complex test campaigns for container orchestration frameworks. We demonstrate the potential of our approach with case studies of the frameworks Kubernetes and Nomad in a self-hosted environment and on the Google Cloud Platform. The presented case studies focus on container startup times, crash recovery, rolling updates, and more.

@inproceedings{straesser2023orchestration, abstract = {Container orchestration frameworks play a critical role in modern cloud computing paradigms such as cloud-native or serverless computing. They significantly impact the quality and cost of service deployment as they manage many performance-critical tasks such as container provisioning, scheduling, scaling, and networking. Consequently, a comprehensive performance assessment of container orchestration frameworks is essential. However, until now, there is no benchmarking approach that covers the many different tasks implemented in such platforms and supports evaluating different technology stacks. In this paper, we present a systematic approach that enables benchmarking of container orchestrators. Based on a definition of container orchestration, we define the core requirements and benchmarking scope for such platforms. Each requirement is then linked to metrics and measurement methods, and a benchmark architecture is proposed. With COFFEE, we introduce a benchmarking tool supporting the definition of complex test campaigns for container orchestration frameworks. We demonstrate the potential of our approach with case studies of the frameworks Kubernetes and Nomad in a self-hosted environment and on the Google Cloud Platform. The presented case studies focus on container startup times, crash recovery, rolling updates, and more.}, address = {New York, NY, USA}, author = {Straesser, Martin and Mathiasch, Jonas and Bauer, Andr\'{e} and Kounev, Samuel}, booktitle = {Proceedings of the 2023 ACM/SPEC International Conference on Performance Engineering}, keywords = {myown}, pages = {187-198}, publisher = {Association for Computing Machinery}, series = {ICPE '23}, title = {A Systematic Approach for Benchmarking of Container Orchestration Frameworks}, year = 2023 }
Autoscaler Evaluation and Configuration: A Practitioner’s Guideline Straesser, Martin; Eismann, Simon; von Kistowski, J\’{o}akim; Bauer, Andr\’{e}; Kounev, Samuel in Proceedings of the 2023 ACM/SPEC International Conference on Performance Engineering, ICPE ’23 (2023).
- [ BibTeX ]
@inproceedings{straesser2023guideline, address = {New York, NY, USA}, author = {Straesser, Martin and Eismann, Simon and von Kistowski, J\'{o}akim and Bauer, Andr\'{e} and Kounev, Samuel}, booktitle = {Proceedings of the 2023 ACM/SPEC International Conference on Performance Engineering}, keywords = {myown}, note = {In print.}, publisher = {Association for Computing Machinery}, series = {ICPE '23}, title = {Autoscaler Evaluation and Configuration: A Practitioner's Guideline}, year = 2023 }
Virtual reality in medical emergencies training: benefits, perceived stress, and learning success Mühling, Tobias; Späth, Isabelle; Backhaus, Joy; Milke, Nathalie; Oberdörfer, Sebastian; Meining, Alexander; Latoschik, Marc Erich; König, Sarah in Multimedia System (2023).
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Medical graduates lack procedural skills experience required to manage emergencies. Recent advances in virtual reality (VR) technology enable the creation of highly immersive learning environments representing easy-to-use and affordable solutions for training with simulation. However, the feasibility in compulsory teaching, possible side effects of immersion, perceived stress, and didactic benefits have to be investigated systematically. VR-based training sessions using head-mounted displays alongside a real-time dynamic physiology system were held by student assistants for small groups followed by debriefing with a tutor. In the pilot study, 36 students rated simulation sickness. In the main study, 97 students completed a virtual scenario as active participants (AP) and 130 students as observers (OBS) from the first-person perspective on a monitor. Participants completed questionnaires for evaluation purposes and exploratory factor analysis was performed on the items. The extent of simulation sickness remained low to acceptable among participants of the pilot study. In the main study, students valued the realistic environment and guided practical exercise. AP perceived the degree of immersion as well as the estimated learning success to be greater than OBS and proved to be more motivated post training. With respect to AP, the factor “sense of control” revealed a typical inverse U-shaped relationship to the scales “didactic value” and “individual learning benefit”. Summing up, curricular implementation of highly immersive VR-based training of emergencies proved feasible and found a high degree of acceptance among medical students. This study also provides insights into how different conceptions of perceived stress distinctively moderate subjective learning success.

@article{muhling2023virtual, abstract = {Medical graduates lack procedural skills experience required to manage emergencies. Recent advances in virtual reality (VR) technology enable the creation of highly immersive learning environments representing easy-to-use and affordable solutions for training with simulation. However, the feasibility in compulsory teaching, possible side effects of immersion, perceived stress, and didactic benefits have to be investigated systematically. VR-based training sessions using head-mounted displays alongside a real-time dynamic physiology system were held by student assistants for small groups followed by debriefing with a tutor. In the pilot study, 36 students rated simulation sickness. In the main study, 97 students completed a virtual scenario as active participants (AP) and 130 students as observers (OBS) from the first-person perspective on a monitor. Participants completed questionnaires for evaluation purposes and exploratory factor analysis was performed on the items. The extent of simulation sickness remained low to acceptable among participants of the pilot study. In the main study, students valued the realistic environment and guided practical exercise. AP perceived the degree of immersion as well as the estimated learning success to be greater than OBS and proved to be more motivated post training. With respect to AP, the factor “sense of control” revealed a typical inverse U-shaped relationship to the scales “didactic value” and “individual learning benefit”. Summing up, curricular implementation of highly immersive VR-based training of emergencies proved feasible and found a high degree of acceptance among medical students. This study also provides insights into how different conceptions of perceived stress distinctively moderate subjective learning success.}, author = {Mühling, Tobias and Späth, Isabelle and Backhaus, Joy and Milke, Nathalie and Oberdörfer, Sebastian and Meining, Alexander and Latoschik, Marc Erich and König, Sarah}, journal = {Multimedia System}, keywords = {oberdoerfer}, title = {Virtual reality in medical emergencies training: benefits, perceived stress, and learning success}, year = 2023 }

2022[ to top ]

YouTube Dataset on Mobile Streaming for Internet Traffic Modeling and Streaming Analysis Loh, Frank; Wamser, Florian; Poignée, Fabian; Geißler, Stefan; Hoßfeld, Tobias in Nature, Scientific Data (2022).
- [ Abstract ]
- [ BibTeX ]
Around 4.9 billion Internet users worldwide watch billions of hours of online video every day. As a result, streaming is by far the predominant type of traffic in communication networks. According to Google statistics, three out of five video views come from mobile devices. Thus, in view of the continuous technological advances in end devices and increasing mobile use, datasets for mobile streaming are indispensable in research but only sparsely dealt with in literature so far. With this public dataset, we provide 1,081 hours of time-synchronous video measurements at network, transport, and application layer with the native YouTube streaming client on mobile devices. The dataset includes 80 network scenarios with 171 different individual bandwidth settings measured in 5,181 runs with limited bandwidth, 1,939 runs with emulated 3 G/4 G traces, and 4,022 runs with pre-defined bandwidth changes. This corresponds to 332 GB video payload. We present the most relevant quality indicators for scientific use, i.e., initial playback delay, streaming video quality, adaptive video quality changes, video rebuffering events, and streaming phases.

@article{info3-article-2022-17, abstract = {Around 4.9 billion Internet users worldwide watch billions of hours of online video every day. As a result, streaming is by far the predominant type of traffic in communication networks. According to Google statistics, three out of five video views come from mobile devices. Thus, in view of the continuous technological advances in end devices and increasing mobile use, datasets for mobile streaming are indispensable in research but only sparsely dealt with in literature so far. With this public dataset, we provide 1,081 hours of time-synchronous video measurements at network, transport, and application layer with the native YouTube streaming client on mobile devices. The dataset includes 80 network scenarios with 171 different individual bandwidth settings measured in 5,181 runs with limited bandwidth, 1,939 runs with emulated 3 G/4 G traces, and 4,022 runs with pre-defined bandwidth changes. This corresponds to 332 GB video payload. We present the most relevant quality indicators for scientific use, i.e., initial playback delay, streaming video quality, adaptive video quality changes, video rebuffering events, and streaming phases.}, author = {Loh, Frank and Wamser, Florian and Poignée, Fabian and Geißler, Stefan and Hoßfeld, Tobias}, journal = {Nature, Scientific Data}, keywords = {huawei}, month = 6, title = {YouTube Dataset on Mobile Streaming for Internet Traffic Modeling and Streaming Analysis}, year = 2022 }
Affordable Measurement Setups for Networking Device Latency with Sub-Microsecond Accuracy Grigorjew, Alexej; Diederich, Philip; Hoßfeld, Tobias; Kellerer, Wolfgang in WueWoWAS’22 KuVS Fachgespraech - Wuerzburg Workshop on Next-Generation Communication Networks (2022).
- [ Abstract ]
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This document presents a networking latency measurement setup that focuses on affordability and universal applicability, and can provide sub-microsecond accuracy. It explains the prerequisites, hardware choices, and considerations to respect during measurement. In addition, it discusses the necessity for exhaustive latency measurements when dealing with high availability and low latency requirements. Preliminary results show that the accuracy is within 0.02 microseconds when used with the Intel I350-T2 network adapter.

@inproceedings{info3-inproceedings-2022-14, abstract = {This document presents a networking latency measurement setup that focuses on affordability and universal applicability, and can provide sub-microsecond accuracy. It explains the prerequisites, hardware choices, and considerations to respect during measurement. In addition, it discusses the necessity for exhaustive latency measurements when dealing with high availability and low latency requirements. Preliminary results show that the accuracy is within 0.02 microseconds when used with the Intel I350-T2 network adapter.}, author = {Grigorjew, Alexej and Diederich, Philip and Hoßfeld, Tobias and Kellerer, Wolfgang}, booktitle = {WueWoWAS'22 KuVS Fachgespraech - Wuerzburg Workshop on Next-Generation Communication Networks}, keywords = {appaware2}, month = 7, title = {Affordable Measurement Setups for Networking Device Latency with Sub-Microsecond Accuracy}, year = 2022 }
A Fully-Immersive Virtual Reality Setup to Study Gait Modulation Palmisano, Chiara; Kullmann, Peter; Hanafi, Ibrahem; Verrecchia, Marta; Latoschik, Marc Erich; Canessa, Andrea; Fischbach, Martin; Isaias, Ioannis Ugo in Frontiers in Human Neuroscience (2022). 16
- [ Abstract ]
- [ BibTeX ]
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Objective: Gait adaptation to environmental challenges is fundamental for independent and safe community ambulation. The possibility of precisely studying gait modulation using standardized protocols of gait analysis closely resembling everyday life scenarios is still an unmet need.Methods: We have developed a fully-immersive virtual reality (VR) environment where subjects have to adjust their walking pattern to avoid collision with a virtual agent (VA) crossing their gait trajectory. We collected kinematic data of 12 healthy young subjects walking in real world (RW) and in the VR environment, both with (VR/A+) and without (VR/A-) the VA perturbation. The VR environment closely resembled the RW scenario of the gait laboratory. To ensure standardization of the obstacle presentation the starting time speed and trajectory of the VA were defined using the kinematics of the participant as detected online during each walking trial.Results: We did not observe kinematic differences between walking in RW and VR/A-, suggesting that our VR environment per se might not induce significant changes in the locomotor pattern. When facing the VA all subjects consistently reduced stride length and velocity while increasing stride duration. Trunk inclination and mediolateral trajectory deviation also facilitated avoidance of the obstacle.Conclusions: This proof-of-concept study shows that our VR/A+ paradigm effectively induced a timely gait modulation in a standardized immersive and realistic scenario. This protocol could be a powerful research tool to study gait modulation and its derangements in relation to aging and clinical conditions.

@article{10.3389/fnhum.2022.783452, abstract = {Objective: Gait adaptation to environmental challenges is fundamental for independent and safe community ambulation. The possibility of precisely studying gait modulation using standardized protocols of gait analysis closely resembling everyday life scenarios is still an unmet need.Methods: We have developed a fully-immersive virtual reality (VR) environment where subjects have to adjust their walking pattern to avoid collision with a virtual agent (VA) crossing their gait trajectory. We collected kinematic data of 12 healthy young subjects walking in real world (RW) and in the VR environment, both with (VR/A+) and without (VR/A-) the VA perturbation. The VR environment closely resembled the RW scenario of the gait laboratory. To ensure standardization of the obstacle presentation the starting time speed and trajectory of the VA were defined using the kinematics of the participant as detected online during each walking trial.Results: We did not observe kinematic differences between walking in RW and VR/A-, suggesting that our VR environment per se might not induce significant changes in the locomotor pattern. When facing the VA all subjects consistently reduced stride length and velocity while increasing stride duration. Trunk inclination and mediolateral trajectory deviation also facilitated avoidance of the obstacle.Conclusions: This proof-of-concept study shows that our VR/A+ paradigm effectively induced a timely gait modulation in a standardized immersive and realistic scenario. This protocol could be a powerful research tool to study gait modulation and its derangements in relation to aging and clinical conditions.}, author = {Palmisano, Chiara and Kullmann, Peter and Hanafi, Ibrahem and Verrecchia, Marta and Latoschik, Marc Erich and Canessa, Andrea and Fischbach, Martin and Isaias, Ioannis Ugo}, journal = {Frontiers in Human Neuroscience}, keywords = {myown}, title = {A Fully-Immersive Virtual Reality Setup to Study Gait Modulation}, volume = 16, year = 2022 }
Towards LoRaWAN without Data Loss: Studying the Performance of Different Channel Access Approaches Loh, Frank; Mehling, Noah; Hoßfeld, Tobias in Sensors (2022).
- [ Abstract ]
- [ BibTeX ]
The Long Range Wide Area Network (LoRaWAN) is one of the fastest growing Internet of Things (IoT) access protocols. It operates in the license free 868 MHz band and gives everyone the possibility to create their own small sensor networks. The drawback of this technology is often unscheduled or random channel access, which leads to message collisions and potential data loss. For that reason, recent literature studies alternative approaches for LoRaWAN channel access. In this work, state-of-the-art random channel access is compared with alternative approaches from the litera- ture by means of collision probability. Furthermore, a time scheduled channel access methodology is presented to completely avoid collisions in LoRaWAN. For this approach, an exhaustive simulation study was conducted and the performance was evaluated with random access cross-traffic. In a general theoretical analysis the limits of the time scheduled approach are discussed to comply with duty cycle regulations in LoRaWAN.

@article{info3-inproceedings-2022-3, abstract = {The Long Range Wide Area Network (LoRaWAN) is one of the fastest growing Internet of Things (IoT) access protocols. It operates in the license free 868 MHz band and gives everyone the possibility to create their own small sensor networks. The drawback of this technology is often unscheduled or random channel access, which leads to message collisions and potential data loss. For that reason, recent literature studies alternative approaches for LoRaWAN channel access. In this work, state-of-the-art random channel access is compared with alternative approaches from the litera- ture by means of collision probability. Furthermore, a time scheduled channel access methodology is presented to completely avoid collisions in LoRaWAN. For this approach, an exhaustive simulation study was conducted and the performance was evaluated with random access cross-traffic. In a general theoretical analysis the limits of the time scheduled approach are discussed to comply with duty cycle regulations in LoRaWAN.}, author = {Loh, Frank and Mehling, Noah and Hoßfeld, Tobias}, journal = {Sensors}, keywords = {5mart}, month = 1, title = {Towards LoRaWAN without Data Loss: Studying the Performance of Different Channel Access Approaches}, year = 2022 }
Simulative Performance Study of Slotted Aloha for LoRaWAN Channel Access Loh, Frank; Mehling, Noah; Geißler, Stefan; Hoßfeld, Tobias in IEEE/IFIP Network Operations and Management Symposium (2022).
- [ Abstract ]
- [ BibTeX ]
Future Internet of Things deployments generate a multitude of new challenges and opportunities. While 5G networks promise massive throughput rates with ultra low delays, many verticals in the areas of Industry 4.0, Smart City, or Smart Agriculture only transmit tiny amounts of data and instead demand high energy efficiency. This is addressed by access technologies like Low Power Wide Area Networks being com- plementary to high performance 5G networks. Especially Long Range Wide Area Network (LoRaWAN) promises transmissions across long distances with low energy requirements with the drawback of unreliable transmission due to potential message collisions through random channel access. For that reason, a broad parameter study simulation for LoRaWAN channel access with slotted Aloha is presented for real world scenarios and influences like clock drifts or cross traffic. The key impact factors of this channel access approach are studied with focus on the collision probability in various scenarios and simulation results are compared to the current state of the art. The contribution of this work are guidelines for parameter settings in a LoRaWAN with slotted Aloha channel access and performance comparisons for different settings. This information is crucial to scale and operate future LoRaWANs.

@inproceedings{info3-article-2022-13, abstract = {Future Internet of Things deployments generate a multitude of new challenges and opportunities. While 5G networks promise massive throughput rates with ultra low delays, many verticals in the areas of Industry 4.0, Smart City, or Smart Agriculture only transmit tiny amounts of data and instead demand high energy efficiency. This is addressed by access technologies like Low Power Wide Area Networks being com- plementary to high performance 5G networks. Especially Long Range Wide Area Network (LoRaWAN) promises transmissions across long distances with low energy requirements with the drawback of unreliable transmission due to potential message collisions through random channel access. For that reason, a broad parameter study simulation for LoRaWAN channel access with slotted Aloha is presented for real world scenarios and influences like clock drifts or cross traffic. The key impact factors of this channel access approach are studied with focus on the collision probability in various scenarios and simulation results are compared to the current state of the art. The contribution of this work are guidelines for parameter settings in a LoRaWAN with slotted Aloha channel access and performance comparisons for different settings. This information is crucial to scale and operate future LoRaWANs.}, author = {Loh, Frank and Mehling, Noah and Geißler, Stefan and Hoßfeld, Tobias}, booktitle = {IEEE/IFIP Network Operations and Management Symposium}, keywords = {can}, month = 4, title = {Simulative Performance Study of Slotted Aloha for LoRaWAN Channel Access}, year = 2022 }
Reducing the Cognitive Load of Playing a Digital Tabletop Game with a Multimodal Interface Zimmerer, Chris; Krop, Philipp; Fischbach, Martin; Latoschik, Marc Erich in CHI Conference on Human Factors in Computing Systems, CHI ’22 (2022).
- [ Abstract ]
- [ BibTeX ]
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Multimodal Interfaces (MMIs) combining speech and spatial input have the potential to elicit minimal cognitive load. Low cognitive load increases effectiveness as well as user satisfaction and is regarded as an important aspect of intuitive use. While this potential has been extensively theorized in the research community, experiments that provide supporting observations based on functional interfaces are still scarce. In particular, there is a lack of studies comparing the commonly used Unimodal Interfaces (UMIs) with theoretically superior synergistic MMI alternatives. Yet, these studies are an essential prerequisite for generalizing results, developing practice-oriented guidelines, and ultimately exploiting the potential of MMIs in a broader range of applications. This work contributes a novel observation towards the resolution of this shortcoming in the context of the following combination of applied interaction techniques, tasks, application domain, and technology: We present a comprehensive evaluation of a synergistic speech & touch MMI and a touch-only menu-based UMI (interaction techniques) for selection and system control tasks in a digital tabletop game (application domain) on an interactive surface (technology). Cognitive load, user experience, and intuitive use are evaluated, with the former being assessed by means of the dual-task paradigm. Our experiment shows that the implemented MMI causes significantly less cognitive load and is perceived significantly more usable and intuitive than the UMI. Based on our results, we derive recommendations for the interface design of digital tabletop games on interactive surfaces. Further, we argue that our results and design recommendations are suitable to be generalized to other application domains on interactive surfaces for selection and system control tasks.

@inproceedings{10.1145/3491102.3502062, abstract = {Multimodal Interfaces (MMIs) combining speech and spatial input have the potential to elicit minimal cognitive load. Low cognitive load increases effectiveness as well as user satisfaction and is regarded as an important aspect of intuitive use. While this potential has been extensively theorized in the research community, experiments that provide supporting observations based on functional interfaces are still scarce. In particular, there is a lack of studies comparing the commonly used Unimodal Interfaces (UMIs) with theoretically superior synergistic MMI alternatives. Yet, these studies are an essential prerequisite for generalizing results, developing practice-oriented guidelines, and ultimately exploiting the potential of MMIs in a broader range of applications. This work contributes a novel observation towards the resolution of this shortcoming in the context of the following combination of applied interaction techniques, tasks, application domain, and technology: We present a comprehensive evaluation of a synergistic speech & touch MMI and a touch-only menu-based UMI (interaction techniques) for selection and system control tasks in a digital tabletop game (application domain) on an interactive surface (technology). Cognitive load, user experience, and intuitive use are evaluated, with the former being assessed by means of the dual-task paradigm. Our experiment shows that the implemented MMI causes significantly less cognitive load and is perceived significantly more usable and intuitive than the UMI. Based on our results, we derive recommendations for the interface design of digital tabletop games on interactive surfaces. Further, we argue that our results and design recommendations are suitable to be generalized to other application domains on interactive surfaces for selection and system control tasks.}, address = {New York, NY, USA}, author = {Zimmerer, Chris and Krop, Philipp and Fischbach, Martin and Latoschik, Marc Erich}, booktitle = {CHI Conference on Human Factors in Computing Systems}, keywords = {myown}, publisher = {Association for Computing Machinery}, series = {CHI '22}, title = {Reducing the Cognitive Load of Playing a Digital Tabletop Game with a Multimodal Interface}, year = 2022 }
An Experience Report on the Suitability of a Distributed Group Encryption Scheme for an IoT Use Case Prantl, Thomas; Engel, Simon; Bauer, Andre; Ben Yahya, Ala Eddine; Herrnleben, Stefan; Iffländer, Lukas; Dmitrienko, Alexandra; Kounev, Samuel in 2022 IEEE 95th Vehicular Technology Conference (VTC2022) (2022).
- [ BibTeX ]
@inproceedings{PrEnBaAlHeIfDmKo2022-IoT/CPS-DistributedGroupEncryption, author = {Prantl, Thomas and Engel, Simon and Bauer, Andre and Ben Yahya, Ala Eddine and Herrnleben, Stefan and Iffländer, Lukas and Dmitrienko, Alexandra and Kounev, Samuel}, booktitle = {2022 IEEE 95th Vehicular Technology Conference (VTC2022)}, keywords = {myown}, organization = {IEEE}, title = {An Experience Report on the Suitability of a Distributed Group Encryption Scheme for an IoT Use Case}, year = 2022 }
The State of Serverless Applications: Collection, Characterization, and Community Consensus Eismann, Simon; Scheuner, Joel; van Eyk, Erwin; Schwinger, Maximilian; Grohmann, Johannes; Herbst, Nikolas; Abad, Cristina; Iosup, Alexandru in Transactions on Software Engineering (2022). 48(10) 4152–4166.
- [ Abstract ]
- [ BibTeX ]
- [ URL ]
Over the last five years, all major cloud platform providers have increased their serverless offerings. Many early adopters report significant benefits for serverless-based over traditional applications, and many companies are considering moving to serverless themselves. However, currently there exist only few, scattered, and sometimes even conflicting reports on when serverless applications are well suited and what the best practices for their implementation are. We address this problem in the present study about the state of serverless applications. We collect descriptions of 89 serverless applications from open-source projects, academic literature, industrial literature, and domain-specific feedback. We analyze 16 characteristics that describe why and when successful adopters are using serverless applications, and how they are building them. We further compare the results of our characterization study to 10 existing, mostly industrial, studies and datasets; this allows us to identify points of consensus across multiple studies, investigate points of disagreement, and overall confirm the validity of our results. The results of this study can help managers to decide if they should adopt serverless technology, engineers to learn about current practices of building serverless applications, and researchers and platform providers to better understand the current landscape of serverless applications.

@article{eismann2021state, abstract = {Over the last five years, all major cloud platform providers have increased their serverless offerings. Many early adopters report significant benefits for serverless-based over traditional applications, and many companies are considering moving to serverless themselves. However, currently there exist only few, scattered, and sometimes even conflicting reports on when serverless applications are well suited and what the best practices for their implementation are. We address this problem in the present study about the state of serverless applications. We collect descriptions of 89 serverless applications from open-source projects, academic literature, industrial literature, and domain-specific feedback. We analyze 16 characteristics that describe why and when successful adopters are using serverless applications, and how they are building them. We further compare the results of our characterization study to 10 existing, mostly industrial, studies and datasets; this allows us to identify points of consensus across multiple studies, investigate points of disagreement, and overall confirm the validity of our results. The results of this study can help managers to decide if they should adopt serverless technology, engineers to learn about current practices of building serverless applications, and researchers and platform providers to better understand the current landscape of serverless applications.}, author = {Eismann, Simon and Scheuner, Joel and van Eyk, Erwin and Schwinger, Maximilian and Grohmann, Johannes and Herbst, Nikolas and Abad, Cristina and Iosup, Alexandru}, journal = {Transactions on Software Engineering}, keywords = {t_journalmagazine}, number = 10, pages = {4152- 4166}, title = {The State of Serverless Applications: Collection, Characterization, and Community Consensus}, volume = 48, year = 2022 }
Plausibility and Perception of Personalized Virtual Humans between Virtual and Augmented Reality Wolf, Erik; Mal, David; Frohnapfel, Viktor; Döllinger, Nina; Wenninger, Stephan; Botsch, Mario; Latoschik, Marc Erich; Wienrich, Carolin in 2022 IEEE International Symposium on Mixed and Augmented Reality (ISMAR) (2022). 489–498.
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This article investigates the effects of different XR displays on the perception and plausibility of personalized virtual humans. We compared immersive virtual reality (VR), video see-through augmented reality (VST AR), and optical see-through AR (OST AR). The personalized virtual alter egos were generated by state-of-the-art photogrammetry methods. 42 participants were repeatedly exposed to animated versions of their 3D-reconstructed virtual alter egos in each of the three XR display conditions. The reconstructed virtual alter egos were additionally modified in body weight for each repetition. We show that the display types lead to different degrees of incongruence between the renderings of the virtual humans and the presentation of the respective environmental backgrounds, leading to significant effects of perceived mismatches as part of a plausibility measurement. The device-related effects were further partly confirmed by subjective misestimations of the modified body weight and the measured spatial presence. Here, the exceedingly incongruent OST AR condition leads to the significantly highest weight misestimations as well as to the lowest perceived spatial presence. However, similar effects could not be confirmed for the affective appraisal (i.e., humanness, eeriness, or attractiveness) of the virtual humans, giving rise to the assumption that these factors might be unrelated to each other.

@inproceedings{wolf2022plausibility, abstract = {This article investigates the effects of different XR displays on the perception and plausibility of personalized virtual humans. We compared immersive virtual reality (VR), video see-through augmented reality (VST AR), and optical see-through AR (OST AR). The personalized virtual alter egos were generated by state-of-the-art photogrammetry methods. 42 participants were repeatedly exposed to animated versions of their 3D-reconstructed virtual alter egos in each of the three XR display conditions. The reconstructed virtual alter egos were additionally modified in body weight for each repetition. We show that the display types lead to different degrees of incongruence between the renderings of the virtual humans and the presentation of the respective environmental backgrounds, leading to significant effects of perceived mismatches as part of a plausibility measurement. The device-related effects were further partly confirmed by subjective misestimations of the modified body weight and the measured spatial presence. Here, the exceedingly incongruent OST AR condition leads to the significantly highest weight misestimations as well as to the lowest perceived spatial presence. However, similar effects could not be confirmed for the affective appraisal (i.e., humanness, eeriness, or attractiveness) of the virtual humans, giving rise to the assumption that these factors might be unrelated to each other.}, author = {Wolf, Erik and Mal, David and Frohnapfel, Viktor and Döllinger, Nina and Wenninger, Stephan and Botsch, Mario and Latoschik, Marc Erich and Wienrich, Carolin}, booktitle = {2022 IEEE International Symposium on Mixed and Augmented Reality (ISMAR)}, keywords = {vitras}, pages = {489-498}, title = {Plausibility and Perception of Personalized Virtual Humans between Virtual and Augmented Reality}, year = 2022 }
Constant Delay Switching: Asynchronous Traffic Shaping with Jitter Control Grigorjew, Alexej; Metzger, Florian; Hoßfeld, Tobias; Specht, Johannes; Götz, Franz-Josef; Chen, Feng; Schmitt, Jürgen in 2022 IFIP Networking Conference (IFIP Networking) (2022).
- [ Abstract ]
- [ BibTeX ]
Recent developments in the Time Sensitive Networking (TSN) group have put forth a number of mechanisms to improve deterministic latency in layer 2 switches. Their shaping approaches differ with respect to prerequisites, flexibility, maximum latency, and latency variation (jitter). Asynchronous solutions provide flexibility in dynamic scenarios, but Credit-Based Shaping (CBS) and Asynchronous Traffic Shaping (ATS) come with a high latency variance, as the minimum latency is not affected by them. Some applications in industrial and automotive use cases require low jitter while trying to avoid a dependency on time synchronization, and even TSN's redundancy mechanism benefits from a lower latency variance. This work is bridging the gap between low-jitter transmission requirements and asynchronous shaping mechanisms. In this paper, the application of a stateless Asynchronous Constant Delay Shaper (ACDS) is discussed. It collects the queuing duration from the previous bridge to delay each frame for the remaining time such that a constant per-hop delay for each frame is achieved. The discussion includes the prerequisites, the mechanism itself, and its technical complexity, as well as a formal analysis of its guaranteed latency by proving its relation to a token-bucket based ATS. Further, two extensions are discussed, and an evaluation shows the applicability of ACDS by comparing its jitter to ATS in a frame-level simulation.

@inproceedings{info3-inproceedings-2022-15, abstract = {Recent developments in the Time Sensitive Networking (TSN) group have put forth a number of mechanisms to improve deterministic latency in layer 2 switches. Their shaping approaches differ with respect to prerequisites, flexibility, maximum latency, and latency variation (jitter). Asynchronous solutions provide flexibility in dynamic scenarios, but Credit-Based Shaping (CBS) and Asynchronous Traffic Shaping (ATS) come with a high latency variance, as the minimum latency is not affected by them. Some applications in industrial and automotive use cases require low jitter while trying to avoid a dependency on time synchronization, and even TSN's redundancy mechanism benefits from a lower latency variance. This work is bridging the gap between low-jitter transmission requirements and asynchronous shaping mechanisms. In this paper, the application of a stateless Asynchronous Constant Delay Shaper (ACDS) is discussed. It collects the queuing duration from the previous bridge to delay each frame for the remaining time such that a constant per-hop delay for each frame is achieved. The discussion includes the prerequisites, the mechanism itself, and its technical complexity, as well as a formal analysis of its guaranteed latency by proving its relation to a token-bucket based ATS. Further, two extensions are discussed, and an evaluation shows the applicability of ACDS by comparing its jitter to ATS in a frame-level simulation.}, author = {Grigorjew, Alexej and Metzger, Florian and Hoßfeld, Tobias and Specht, Johannes and Götz, Franz-Josef and Chen, Feng and Schmitt, Jürgen}, booktitle = {2022 IFIP Networking Conference (IFIP Networking)}, keywords = {kosinu5}, month = 6, title = {Constant Delay Switching: Asynchronous Traffic Shaping with Jitter Control}, year = 2022 }
Social Robots in Applied Settings: A Long-Term Study on Adaptive Robotic Tutors in Higher Education Donnermann, Melissa; Schaper, Philipp; Lugrin, Birgit in Frontiers in Robotics and AI (2022). 9
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- [ URL ]
@article{Donnermann_2022, author = {Donnermann, Melissa and Schaper, Philipp and Lugrin, Birgit}, journal = {Frontiers in Robotics and AI}, keywords = {schaper}, publisher = {Frontiers Media SA}, title = {Social Robots in Applied Settings: A Long-Term Study on Adaptive Robotic Tutors in Higher Education}, volume = 9, year = 2022 }
Interactive Hemodynamic Simulation Model of a Cross-scale Cardiovascular System Hofmann, Sarah; M{\"u}ller, Andreas; von Mammen, Sebastian in ANNSIM 22 (2022).
- [ BibTeX ]
- [ URL ]
@inproceedings{Hofmann2022INTERACTIVEHS, author = {Hofmann, Sarah and M{\"u}ller, Andreas and von Mammen, Sebastian}, booktitle = {ANNSIM 22}, keywords = {myown}, publisher = {Society for Modeling & Simulation International (SCS)}, title = {Interactive Hemodynamic Simulation Model of a Cross-scale Cardiovascular System}, year = 2022 }
Learning Classifier Systems as Recommender Systems Babu, Sooraj K; von Mammen, Sebastian in Lifelike Computing Systems Workshop LIFELIKE 2022 (2022).
- [ Abstract ]
- [ BibTeX ]
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A multitude of software domains, ranging from e-commerce services to personal digital assistants, rely on recommender systems (RS) to enhance their performance and customer experience. There are several established approaches to RS, including algorithms, namely, collaborative filtering, content based filtering, and various hybrid systems that use different verticals of data, such as the user’s preferences, the metadata of items to be suggested, etc., to generate recommendations. Contrary to those, we adopt a classifier system to benefit from its rule-based knowledge representation and interwoven learning mechanisms. In this paper, we present our approach and elaborate on its potential use to flexibly and effectively guide a user through the application of an authoring platform.

@inproceedings{babu2022learning, abstract = {A multitude of software domains, ranging from e-commerce services to personal digital assistants, rely on recommender systems (RS) to enhance their performance and customer experience. There are several established approaches to RS, including algorithms, namely, collaborative filtering, content based filtering, and various hybrid systems that use different verticals of data, such as the user’s preferences, the metadata of items to be suggested, etc., to generate recommendations. Contrary to those, we adopt a classifier system to benefit from its rule-based knowledge representation and interwoven learning mechanisms. In this paper, we present our approach and elaborate on its potential use to flexibly and effectively guide a user through the application of an authoring platform.}, author = {Babu, Sooraj K and von Mammen, Sebastian}, booktitle = {Lifelike Computing Systems Workshop LIFELIKE 2022}, keywords = {via-vr}, title = {Learning Classifier Systems as Recommender Systems}, year = 2022 }
Semi-unsupervised Learning for Time Series Classification Davidson, Padraig; Steininger, Michael; Huhn, André; Krause, Anna; Hotho, Andreas in Milets@KDD (2022).
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Time series are ubiquitous and therefore inherently hard to analyze and ultimately to label or cluster. With the rise of the Internet of Things (IoT) and its smart devices, data is collected in large amounts any given second. The collected data is rich in information, as one can detect accidents (e.g. cars) in real time, or assess injury/sickness over a given time span (e.g. health devices). Due to its chaotic nature and massive amounts of datapoints, timeseries are hard to label manually. Furthermore new classes within the data could emerge over time (contrary to e.g. handwritten digits), which would require relabeling the data. In this paper we present SuSL4TS, a deep generative Gaussian mixture model for semi-unsupervised learning, to classify time series data. With our approach we can alleviate manual labeling steps, since we can detect sparsely labeled classes (semi-supervised) and identify emerging classes hidden in the data (unsupervised). We demonstrate the efficacy of our approach with established time series classification datasets from different domains.

@article{davidson2022semiunsupervised, abstract = {Time series are ubiquitous and therefore inherently hard to analyze and ultimately to label or cluster. With the rise of the Internet of Things (IoT) and its smart devices, data is collected in large amounts any given second. The collected data is rich in information, as one can detect accidents (e.g. cars) in real time, or assess injury/sickness over a given time span (e.g. health devices). Due to its chaotic nature and massive amounts of datapoints, timeseries are hard to label manually. Furthermore new classes within the data could emerge over time (contrary to e.g. handwritten digits), which would require relabeling the data. In this paper we present SuSL4TS, a deep generative Gaussian mixture model for semi-unsupervised learning, to classify time series data. With our approach we can alleviate manual labeling steps, since we can detect sparsely labeled classes (semi-supervised) and identify emerging classes hidden in the data (unsupervised). We demonstrate the efficacy of our approach with established time series classification datasets from different domains.}, author = {Davidson, Padraig and Steininger, Michael and Huhn, André and Krause, Anna and Hotho, Andreas}, journal = {Milets@KDD}, keywords = {timeseries}, publisher = {arXiv}, title = {Semi-unsupervised Learning for Time Series Classification}, year = 2022 }
Point me to your Opinion, {S}en{P}oi Pfister, Jan; Wankerl, Sebastian; Hotho, Andreas in Proceedings of the 16th International Workshop on Semantic Evaluation (SemEval-2022) (2022). 1313–1323.
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Structured Sentiment Analysis is the task of extracting sentiment tuples in a graph structure commonly from review texts. We adapt the Aspect-Based Sentiment Analysis pointer network BARTABSA to model this tuple extraction as a sequence prediction task and extend their output grammar to account for the increased complexity of Structured Sentiment Analysis. To predict structured sentiment tuples in languages other than English we swap BART for a multilingual mT5 and introduce a novel Output Length Regularization to mitigate overfitting to common target sequence lengths, thereby improving the performance of the model by up to 70{\%}. We evaluate our approach on seven datasets in five languages including a zero shot crosslingual setting.

@inproceedings{pfister-etal-2022-senpoi, abstract = {Structured Sentiment Analysis is the task of extracting sentiment tuples in a graph structure commonly from review texts. We adapt the Aspect-Based Sentiment Analysis pointer network BARTABSA to model this tuple extraction as a sequence prediction task and extend their output grammar to account for the increased complexity of Structured Sentiment Analysis. To predict structured sentiment tuples in languages other than English we swap BART for a multilingual mT5 and introduce a novel Output Length Regularization to mitigate overfitting to common target sequence lengths, thereby improving the performance of the model by up to 70{\%}. We evaluate our approach on seven datasets in five languages including a zero shot crosslingual setting.}, address = {Seattle, United States}, author = {Pfister, Jan and Wankerl, Sebastian and Hotho, Andreas}, booktitle = {Proceedings of the 16th International Workshop on Semantic Evaluation (SemEval-2022)}, keywords = {sentiment}, month = {jul}, pages = {1313–1323}, publisher = {Association for Computational Linguistics}, title = {Point me to your Opinion, {S}en{P}oi}, year = 2022 }
Open ERP System Data For Occupational Fraud Detection Tritscher, Julian; Gwinner, Fabian; Schlör, Daniel; Krause, Anna; Hotho, Andreas in arxiv (2022).
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@article{tritscher2022erpData, author = {Tritscher, Julian and Gwinner, Fabian and Schlör, Daniel and Krause, Anna and Hotho, Andreas}, journal = {arxiv}, keywords = {myown}, title = {Open ERP System Data For Occupational Fraud Detection}, year = 2022 }
{LSX} team5 at {S}em{E}val-2022 Task 8: Multilingual News Article Similarity Assessment based on Word- and Sentence Mover{’}s Distance Heil, Stefan; Kopp, Karina; Zehe, Albin; Kobs, Konstantin; Hotho, Andreas in Proceedings of the 16th International Workshop on Semantic Evaluation (SemEval-2022) (2022). 1190–1195.
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This paper introduces our submission for the SemEval 2022 Task 8: Multilingual News Article Similarity. The task of the competition consisted of the development of a model, capable of determining the similarity between pairs of multilingual news articles. To address this challenge, we evaluated the Word Mover{'}s Distance in conjunction with word embeddings from ConceptNet Numberbatch and term frequencies of WorldLex, as well the Sentence Mover{'}s Distance based on sentence embeddings generated by pretrained transformer models of Sentence-BERT. To facilitate the comparison of multilingual articles with Sentence-BERT models, we deployed a Neural Machine Translation system. All our models achieve stable results in multilingual similarity estimation without learning parameters.

@inproceedings{heil2022lsxteam5, abstract = {This paper introduces our submission for the SemEval 2022 Task 8: Multilingual News Article Similarity. The task of the competition consisted of the development of a model, capable of determining the similarity between pairs of multilingual news articles. To address this challenge, we evaluated the Word Mover{'}s Distance in conjunction with word embeddings from ConceptNet Numberbatch and term frequencies of WorldLex, as well the Sentence Mover{'}s Distance based on sentence embeddings generated by pretrained transformer models of Sentence-BERT. To facilitate the comparison of multilingual articles with Sentence-BERT models, we deployed a Neural Machine Translation system. All our models achieve stable results in multilingual similarity estimation without learning parameters.}, address = {Seattle, United States}, author = {Heil, Stefan and Kopp, Karina and Zehe, Albin and Kobs, Konstantin and Hotho, Andreas}, booktitle = {Proceedings of the 16th International Workshop on Semantic Evaluation (SemEval-2022)}, keywords = {similarity}, month = {jul}, pages = {1190–1195}, publisher = {Association for Computational Linguistics}, title = {{LSX} team5 at {S}em{E}val-2022 Task 8: Multilingual News Article Similarity Assessment based on Word- and Sentence Mover{'}s Distance}, year = 2022 }
{W}ue{D}evils at {S}em{E}val-2022 Task 8: Multilingual News Article Similarity via Pair-Wise Sentence Similarity Matrices Wangsadirdja, Dirk; Heinickel, Felix; Trapp, Simon; Zehe, Albin; Kobs, Konstantin; Hotho, Andreas in Proceedings of the 16th International Workshop on Semantic Evaluation (SemEval-2022) (2022). 1235–1243.
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We present a system that creates pair-wise cosine and arccosine sentence similarity matrices using multilingual sentence embeddings obtained from pre-trained SBERT and Universal Sentence Encoder (USE) models respectively. For each news article sentence, it searches the most similar sentence from the other article and computes an average score. Further, a convolutional neural network calculates a total similarity score for the article pairs on these matrices. Finally, a random forest regressor merges the previous results to a final score that can optionally be extended with a publishing date score.

@inproceedings{wangsadirdja2022wuedevils, abstract = {We present a system that creates pair-wise cosine and arccosine sentence similarity matrices using multilingual sentence embeddings obtained from pre-trained SBERT and Universal Sentence Encoder (USE) models respectively. For each news article sentence, it searches the most similar sentence from the other article and computes an average score. Further, a convolutional neural network calculates a total similarity score for the article pairs on these matrices. Finally, a random forest regressor merges the previous results to a final score that can optionally be extended with a publishing date score.}, address = {Seattle, United States}, author = {Wangsadirdja, Dirk and Heinickel, Felix and Trapp, Simon and Zehe, Albin and Kobs, Konstantin and Hotho, Andreas}, booktitle = {Proceedings of the 16th International Workshop on Semantic Evaluation (SemEval-2022)}, keywords = {similarity}, month = {jul}, pages = {1235–1243}, publisher = {Association for Computational Linguistics}, title = {{W}ue{D}evils at {S}em{E}val-2022 Task 8: Multilingual News Article Similarity via Pair-Wise Sentence Similarity Matrices}, year = 2022 }
Analyzing Eye Tracking Data in Mirror Exposure Döllinger, Nina; Göttfert, Christopher; Wolf, Erik; Mal, David; Latoschik, Marc Erich; Wienrich, Carolin in Proceedings of the Conference on Mensch und Computer, MuC ’22 (2022). (Vol. Proceedings of Mensch Und Computer 2022) 513–517.
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Mirror exposure is an important method in the treatment of body image disturbances. Eye tracking can support the unaffected assessment of attention biases during mirror exposure. However, the analysis of eye tracking data in mirror exposure comes with various difficulties and is associated with a high manual workload during data processing. We present an automated data processing framework that enables us to determine any body part as an area of interest without placing markers on the bodies of participants. A short, formative user study proved the quality compared to the gold standard. The automatic processing and openness for different systems allow a broad range of applications.

@inproceedings{dollinger2022eyetracking, abstract = {Mirror exposure is an important method in the treatment of body image disturbances. Eye tracking can support the unaffected assessment of attention biases during mirror exposure. However, the analysis of eye tracking data in mirror exposure comes with various difficulties and is associated with a high manual workload during data processing. We present an automated data processing framework that enables us to determine any body part as an area of interest without placing markers on the bodies of participants. A short, formative user study proved the quality compared to the gold standard. The automatic processing and openness for different systems allow a broad range of applications.}, address = {New York, NY, USA}, author = {Döllinger, Nina and Göttfert, Christopher and Wolf, Erik and Mal, David and Latoschik, Marc Erich and Wienrich, Carolin}, booktitle = {Proceedings of the Conference on Mensch und Computer}, keywords = {vitras}, pages = {513–517}, publisher = {Association for Computing Machinery}, series = {MuC '22}, title = {Analyzing Eye Tracking Data in Mirror Exposure}, volume = {Proceedings of Mensch Und Computer 2022}, year = 2022 }
Opportunities and Challenges of Virtual Reality in Healthcare – A Domain Experts Inquiry Halbig, Andreas; Babu, Sooraj K.; Gatter, Shirin; Latoschik, Marc Erich; Brukamp, Kirsten; von Mammen, Sebastian in Frontiers in Virtual Reality (2022). 3
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In recent years, the applications and accessibility of Virtual Reality (VR) for the healthcare sector have continued to grow. However, so far, most VR applications are only relevant in research settings. Information about what healthcare professionals would need to independently integrate VR applications into their daily working routines is missing. The actual needs and concerns of the people who work in the healthcare sector are often disregarded in the development of VR applications, even though they are the ones who are supposed to use them in practice. By means of this study, we systematically involve health professionals in the development process of VR applications. In particular, we conducted an online survey with 102 healthcare professionals based on a video prototype which demonstrates a software platform that allows them to create and utilise VR experiences on their own. For this study, we adapted and extended the Technology Acceptance Model (TAM). The survey focused on the perceived usefulness and the ease of use of such a platform, as well as the attitude and ethical concerns the users might have. The results show a generally positive attitude toward such a software platform. The users can imagine various use cases in different health domains. However, the perceived usefulness is tied to the actual ease of use of the platform and sufficient support for learning and working with the platform. In the discussion, we explain how these results can be generalized to facilitate the integration of VR in healthcare practice.

@article{halbig:2022q, abstract = {In recent years, the applications and accessibility of Virtual Reality (VR) for the healthcare sector have continued to grow. However, so far, most VR applications are only relevant in research settings. Information about what healthcare professionals would need to independently integrate VR applications into their daily working routines is missing. The actual needs and concerns of the people who work in the healthcare sector are often disregarded in the development of VR applications, even though they are the ones who are supposed to use them in practice. By means of this study, we systematically involve health professionals in the development process of VR applications. In particular, we conducted an online survey with 102 healthcare professionals based on a video prototype which demonstrates a software platform that allows them to create and utilise VR experiences on their own. For this study, we adapted and extended the Technology Acceptance Model (TAM). The survey focused on the perceived usefulness and the ease of use of such a platform, as well as the attitude and ethical concerns the users might have. The results show a generally positive attitude toward such a software platform. The users can imagine various use cases in different health domains. However, the perceived usefulness is tied to the actual ease of use of the platform and sufficient support for learning and working with the platform. In the discussion, we explain how these results can be generalized to facilitate the integration of VR in healthcare practice.}, author = {Halbig, Andreas and Babu, Sooraj K. and Gatter, Shirin and Latoschik, Marc Erich and Brukamp, Kirsten and von Mammen, Sebastian}, journal = {Frontiers in Virtual Reality}, keywords = {via-vr}, title = {Opportunities and Challenges of Virtual Reality in Healthcare – A Domain Experts Inquiry}, volume = 3, year = 2022 }
SCRAPS: Scalable Collective Remote Attestation for Pub-Sub IoT Networks with Untrusted Proxy Verifier Petzi, Lukas; Ben Yahya, Ala Eddine; Dmitrienko, Alexandra; Tsudik, Gene; Prantl, Thomas; Kounev, Samuel (2022). (Vol. USENIX Security ’22)
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Remote Attestation (RA) is a basic security mechanism that detects malicious presence on various types of computing components, e.g., IoT devices. In a typical IoT setting, RA involves a trusted Verifier that sends a challenge to an untrusted remote Prover, which must in turn reply with a fresh and authentic evidence of being in a trustworthy state. However,most current RA schemes assume a central Verifier, which rep-resents a single point of failure. This feature is problematic when mutually suspicious stakeholders are involved. Furthermore, scalability issues arise as the number of IoT devices (Provers) grows. Although some RA schemes allow peer Provers to act as Verifiers, they involve unrealistic (for IoT devices) requirements, such as time synchronization and synchronous communication. Moreover, they incur heavy memory, computation,and communication burdens, while not considering sleeping or otherwise disconnected devices. Motivated by the need to address these limitations, we construct Scalable Collective Remote Attestation for Pub-Sub (SCRAPS), a novel collective RA scheme. It achieves scalability by outsourcing Verifier duties to a smart contract and mitigates DoS attacks against both Provers and Verifiers. It also removes the need for synchronous communication. Furthermore,RA evidence in SCRAPS is publicly verifiable, which significantly reduces the number of attestation evidence computations, thus lowering Prover burden. We report on a prototype of SCRAPS over Hyperledger Sawtooth (a blockchain geared for IoT use-cases) and evaluate its performance, scalability, and security aspects.

@proceedings{petzi2022scraps, abstract = {Remote Attestation (RA) is a basic security mechanism that detects malicious presence on various types of computing components, e.g., IoT devices. In a typical IoT setting, RA involves a trusted Verifier that sends a challenge to an untrusted remote Prover, which must in turn reply with a fresh and authentic evidence of being in a trustworthy state. However,most current RA schemes assume a central Verifier, which rep-resents a single point of failure. This feature is problematic when mutually suspicious stakeholders are involved. Furthermore, scalability issues arise as the number of IoT devices (Provers) grows. Although some RA schemes allow peer Provers to act as Verifiers, they involve unrealistic (for IoT devices) requirements, such as time synchronization and synchronous communication. Moreover, they incur heavy memory, computation,and communication burdens, while not considering sleeping or otherwise disconnected devices. Motivated by the need to address these limitations, we construct Scalable Collective Remote Attestation for Pub-Sub (SCRAPS), a novel collective RA scheme. It achieves scalability by outsourcing Verifier duties to a smart contract and mitigates DoS attacks against both Provers and Verifiers. It also removes the need for synchronous communication. Furthermore,RA evidence in SCRAPS is publicly verifiable, which significantly reduces the number of attestation evidence computations, thus lowering Prover burden. We report on a prototype of SCRAPS over Hyperledger Sawtooth (a blockchain geared for IoT use-cases) and evaluate its performance, scalability, and security aspects.}, author = {Petzi, Lukas and Ben Yahya, Ala Eddine and Dmitrienko, Alexandra and Tsudik, Gene and Prantl, Thomas and Kounev, Samuel}, keywords = {myown}, note = {Coming Soon}, title = {SCRAPS: Scalable Collective Remote Attestation for Pub-Sub IoT Networks with Untrusted Proxy Verifier}, volume = {USENIX Security '22}, year = 2022 }
Attitude of Nutrition Experts Toward Psychotherapy and Virtual Reality as Part of Obesity Treatment—An Online Survey Gemesi, Kathrin; Holzmann, Sophie Laura; Hochrein, Regine; D{\"o}llinger, Nina; Wienrich, Carolin; Weinberger, Natascha-Alexandra; Luck-Sikorski, Claudia; Holzapfel, Christina in Frontiers in Psychiatry (2022). 13
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@article{gemesi2022attitude, author = {Gemesi, Kathrin and Holzmann, Sophie Laura and Hochrein, Regine and D{\"o}llinger, Nina and Wienrich, Carolin and Weinberger, Natascha-Alexandra and Luck-Sikorski, Claudia and Holzapfel, Christina}, journal = {Frontiers in Psychiatry}, keywords = {vitras}, publisher = {Frontiers Media SA}, title = {Attitude of Nutrition Experts Toward Psychotherapy and Virtual Reality as Part of Obesity Treatment—An Online Survey}, volume = 13, year = 2022 }
Embodied Gambling–Investigating the Influence of Level of Embodiment, Avatar Appearance, and Virtual Environment Design on an Online VR Slot Machine Oberdörfer, Sebastian; Schraudt, David; Latoschik, Marc Erich in Frontiers in Virtual Reality (2022). 3
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Slot machines are one of the most played games by players suffering from gambling disorder. New technologies like immersive Virtual Reality (VR) offer more possibilities to exploit erroneous beliefs in the context of gambling. Recent research indicates a higher risk potential when playing a slot machine in VR than on desktop. To continue this investigation, we evaluate the effects of providing different degrees of embodiment, i.e., minimal and full embodiment. The avatars used for the full embodiment further differ in their appearance, i.e., they elicit a high or a low socio-economic status. The virtual environment (VE) design can cause a potential influence on the overall gambling behavior. Thus, we also embed the slot machine in two different VEs that differ in their emotional design: a colorful underwater playground environment and a virtual counterpart of our lab. These design considerations resulted in four different versions of the same VR slot machine: 1) full embodiment with high socio-economic status, 2) full embodiment with low socio-economic status, 3) minimal embodiment playground VE, and 4) minimal embodiment laboratory VE. Both full embodiment versions also used the playground VE. We determine the risk potential by logging gambling frequency as well as stake size, and measuring harm-inducing factors, i.e., dissociation, urge to gamble, dark flow, and illusion of control, using questionnaires. Following a between groups experimental design, 82 participants played for 20 game rounds one of the four versions. We recruited our sample from the students enrolled at the University of Würzburg. Our safety protocol ensured that only participants without any recent gambling activity took part in the experiment. In this comparative user study, we found no effect of the embodiment nor VE design on neither the gambling frequency, stake sizes, nor risk potential. However, our results provide further support for the hypothesis of the higher visual angle on gambling stimuli and hence the increased emotional response being the true cause for the higher risk potential.

@article{oberdorfer2022embodied, abstract = {Slot machines are one of the most played games by players suffering from gambling disorder. New technologies like immersive Virtual Reality (VR) offer more possibilities to exploit erroneous beliefs in the context of gambling. Recent research indicates a higher risk potential when playing a slot machine in VR than on desktop. To continue this investigation, we evaluate the effects of providing different degrees of embodiment, i.e., minimal and full embodiment. The avatars used for the full embodiment further differ in their appearance, i.e., they elicit a high or a low socio-economic status. The virtual environment (VE) design can cause a potential influence on the overall gambling behavior. Thus, we also embed the slot machine in two different VEs that differ in their emotional design: a colorful underwater playground environment and a virtual counterpart of our lab. These design considerations resulted in four different versions of the same VR slot machine: 1) full embodiment with high socio-economic status, 2) full embodiment with low socio-economic status, 3) minimal embodiment playground VE, and 4) minimal embodiment laboratory VE. Both full embodiment versions also used the playground VE. We determine the risk potential by logging gambling frequency as well as stake size, and measuring harm-inducing factors, i.e., dissociation, urge to gamble, dark flow, and illusion of control, using questionnaires. Following a between groups experimental design, 82 participants played for 20 game rounds one of the four versions. We recruited our sample from the students enrolled at the University of Würzburg. Our safety protocol ensured that only participants without any recent gambling activity took part in the experiment. In this comparative user study, we found no effect of the embodiment nor VE design on neither the gambling frequency, stake sizes, nor risk potential. However, our results provide further support for the hypothesis of the higher visual angle on gambling stimuli and hence the increased emotional response being the true cause for the higher risk potential.}, author = {Oberdörfer, Sebastian and Schraudt, David and Latoschik, Marc Erich}, journal = {Frontiers in Virtual Reality}, keywords = {oberdoerfer}, title = {Embodied Gambling–Investigating the Influence of Level of Embodiment, Avatar Appearance, and Virtual Environment Design on an Online VR Slot Machine}, volume = 3, year = 2022 }
Controlling the STAGE: A High-Level Control System for Virtual Audiences In Virtual Reality Glémarec, Yann; Lugrin, Jean-Luc; Bosser, Anne-Gwenn; Buche, Cedric; Latoschik, Marc Erich in Frontiers in Virtual Reality – Virtual Reality and Human Behaviour (2022).
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This article presents a novel method for controlling a virtual audience system (VAS) in Virtual Reality (VR) application, called STAGE, which has been originally designed for supervised public speaking training in university seminars dedicated to the preparation and delivery of scientific talks. We are interested in creating pedagogical \emph{narratives}: narratives encompass affective phenomena and rather than organizing events changing the course of a training scenario, pedagogical plans using our system focus on organizing the affects it arouses for the trainees. Efficiently controlling a virtual audience towards a specific training objective while evaluating the speaker's performance presents a challenge for a seminar instructor: the high level of cognitive and physical demands required to be able to control the virtual audience, whilst evaluating speaker's performance, adjusting and allowing it to quickly react to the user’s behaviors and interactions. It is indeed a critical limitation of a number of existing systems that they rely on a Wizard of Oz approach, where the tutor drives the audience in reaction to the user’s performance. We address this problem by integrating with a VAS a high-level control component for tutors, which allows using predefined audience behavior rules, defining custom ones, as well as intervening during run-time for finer control of the unfolding of the pedagogical plan. At its core, this component offers a tool to program, select, modify and monitor interactive training narratives using a high-level representation. The STAGE offers the following features: i) a high-level API to program pedagogical narratives focusing on a specific public speaking situation and training objectives, ii) an interactive visualization interface iii) computation and visualization of user metrics, iv) a semi-autonomous virtual audience composed of virtual spectators with automatic reactions to the speaker and surrounding spectators while following the pedagogical plan V) and the possibility for the instructor to embody a virtual spectator to ask questions or guide the speaker from within the Virtual Environment. We present here the design, implementation of the tutoring system and its integration in STAGE, and discuss its reception by end-users.

@article{glemarec2022controlling, abstract = {This article presents a novel method for controlling a virtual audience system (VAS) in Virtual Reality (VR) application, called STAGE, which has been originally designed for supervised public speaking training in university seminars dedicated to the preparation and delivery of scientific talks. We are interested in creating pedagogical \emph{narratives}: narratives encompass affective phenomena and rather than organizing events changing the course of a training scenario, pedagogical plans using our system focus on organizing the affects it arouses for the trainees. Efficiently controlling a virtual audience towards a specific training objective while evaluating the speaker's performance presents a challenge for a seminar instructor: the high level of cognitive and physical demands required to be able to control the virtual audience, whilst evaluating speaker's performance, adjusting and allowing it to quickly react to the user’s behaviors and interactions. It is indeed a critical limitation of a number of existing systems that they rely on a Wizard of Oz approach, where the tutor drives the audience in reaction to the user’s performance. We address this problem by integrating with a VAS a high-level control component for tutors, which allows using predefined audience behavior rules, defining custom ones, as well as intervening during run-time for finer control of the unfolding of the pedagogical plan. At its core, this component offers a tool to program, select, modify and monitor interactive training narratives using a high-level representation. The STAGE offers the following features: i) a high-level API to program pedagogical narratives focusing on a specific public speaking situation and training objectives, ii) an interactive visualization interface iii) computation and visualization of user metrics, iv) a semi-autonomous virtual audience composed of virtual spectators with automatic reactions to the speaker and surrounding spectators while following the pedagogical plan V) and the possibility for the instructor to embody a virtual spectator to ask questions or guide the speaker from within the Virtual Environment. We present here the design, implementation of the tutoring system and its integration in STAGE, and discuss its reception by end-users.}, author = {Glémarec, Yann and Lugrin, Jean-Luc and Bosser, Anne-Gwenn and Buche, Cedric and Latoschik, Marc Erich}, journal = {Frontiers in Virtual Reality – Virtual Reality and Human Behaviour}, keywords = {myown}, title = {Controlling the STAGE: A High-Level Control System for Virtual Audiences In Virtual Reality}, year = 2022 }
A case study on the stability of performance tests for serverless applications Eismann, Simon; Costa, Diego; Liao, Lizhi; Bezemer, Cor-Paul; Shang, Weiyi; van Hoorn, André; Kounev, Samuel in Journal of Systems and Software (JSS) (2022). 189
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Context: While in serverless computing, application resource management and operational concerns are generally delegated to the cloud provider, ensuring that serverless applications meet their performance requirements is still a responsibility of the developers. Performance testing is a commonly used performance assessment practice; however, it traditionally requires visibility of the resource environment. Objective: In this study, we investigate whether performance tests of serverless applications are stable, that is, if their results are reproducible, and what implications the serverless paradigm has for performance tests. Method: We conduct a case study where we collect two datasets of performance test results: (a) repetitions of performance tests for varying memory size and load intensities and (b) three repetitions of the same performance test every day for ten months. Results: We find that performance tests of serverless applications are comparatively stable if conducted on the same day. However, we also observe short-term performance variations and frequent long-term performance changes. Conclusion: Performance tests for serverless applications can be stable; however, the serverless model impacts the planning, execution, and analysis of performance tests.

@article{eismann2022study, abstract = {Context: While in serverless computing, application resource management and operational concerns are generally delegated to the cloud provider, ensuring that serverless applications meet their performance requirements is still a responsibility of the developers. Performance testing is a commonly used performance assessment practice; however, it traditionally requires visibility of the resource environment. Objective: In this study, we investigate whether performance tests of serverless applications are stable, that is, if their results are reproducible, and what implications the serverless paradigm has for performance tests. Method: We conduct a case study where we collect two datasets of performance test results: (a) repetitions of performance tests for varying memory size and load intensities and (b) three repetitions of the same performance test every day for ten months. Results: We find that performance tests of serverless applications are comparatively stable if conducted on the same day. However, we also observe short-term performance variations and frequent long-term performance changes. Conclusion: Performance tests for serverless applications can be stable; however, the serverless model impacts the planning, execution, and analysis of performance tests.}, author = {Eismann, Simon and Costa, Diego and Liao, Lizhi and Bezemer, Cor-Paul and Shang, Weiyi and van Hoorn, André and Kounev, Samuel}, journal = {Journal of Systems and Software (JSS)}, keywords = {myown}, title = {A case study on the stability of performance tests for serverless applications}, volume = 189, year = 2022 }
Data Usage in IoT: A Characterization of GTP Tunnels in M2M Mobile Networks Raffeck, Simon; Geißler, Stefan; Krolikowski, Michael; Gebert, Steffen; Hoßfeld, Tobias in 2nd IFIP/IEEE International workshop on Fully-Flexible Internet Architectures and Protocols for the Next-Generation Tactile Internet (FlexNGIA) (2022).
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IoT and M2M devices have seen a significant growth in usage and deployment over the last years. Gaining insight into device and data usage behavior exhibited by the participants of mobile networks is elementary for MNO and MVNO to scale their networks and provide a reliable service. This work aims to make use of its first of a kind dataset, spanning multiple countries and MNO, to provide a detailed characterization of GTP tunnels and devices. To this end, general statistics are used to describe the observed data traffic focusing on the distribution of the tunnel duration and volume as well as periodic device behavior. An approximate metric is introduced to analyze the periodicity and synchronicity of IoT devices. Lastly, we publish the data investigated in this work and provide a large scale dataset on the data usage behavior of IoT devices to interested researchers.

@inproceedings{info3-inproceedings-2022-5, abstract = {IoT and M2M devices have seen a significant growth in usage and deployment over the last years. Gaining insight into device and data usage behavior exhibited by the participants of mobile networks is elementary for MNO and MVNO to scale their networks and provide a reliable service. This work aims to make use of its first of a kind dataset, spanning multiple countries and MNO, to provide a detailed characterization of GTP tunnels and devices. To this end, general statistics are used to describe the observed data traffic focusing on the distribution of the tunnel duration and volume as well as periodic device behavior. An approximate metric is introduced to analyze the periodicity and synchronicity of IoT devices. Lastly, we publish the data investigated in this work and provide a large scale dataset on the data usage behavior of IoT devices to interested researchers.}, author = {Raffeck, Simon and Geißler, Stefan and Krolikowski, Michael and Gebert, Steffen and Hoßfeld, Tobias}, booktitle = {2nd IFIP/IEEE International workshop on Fully-Flexible Internet Architectures and Protocols for the Next-Generation Tactile Internet (FlexNGIA)}, keywords = {can}, month = 4, title = {Data Usage in IoT: A Characterization of GTP Tunnels in M2M Mobile Networks}, year = 2022 }
IT-Supported Request Management for Clinical Radiology: Contextual Design and Remote Prototype Testing Krop, Philipp; Straka, Samantha; Ullrich, Melanie; Ertl, Maximilian; Latoschik, Marc Erich in CHI Conference on Human Factors in Computing Systems Extended Abstracts, CHI EA ’22 (2022). 1–8.
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Management of radiology requests in larger clinical contexts is characterized by a complex and distributed workflow. In our partner hospital, representing many similar clinics, these processes often still rely on exchanging physical papers and forms, making patient or case data challenging to access. This often leads to phone calls with long waiting queues, which are time-inefficient and result in frequent interrupts. We report on a user-centered design approach based on Rapid Contextual Design with an additional focus group to optimize and iteratively develop a new workflow. Participants found our prototypes fast and intuitive, the design clean and consistent, relevant information easy to access, and the request process fast and easy. Due to the COVID pandemic, we switched to remote prototype testing, which yielded equally good feedback and increased the participation rate. In the end, we propose best practices for remote prototype testing in hospitals with complex and distributed workflows.

@inproceedings{krop2022a, abstract = {Management of radiology requests in larger clinical contexts is characterized by a complex and distributed workflow. In our partner hospital, representing many similar clinics, these processes often still rely on exchanging physical papers and forms, making patient or case data challenging to access. This often leads to phone calls with long waiting queues, which are time-inefficient and result in frequent interrupts. We report on a user-centered design approach based on Rapid Contextual Design with an additional focus group to optimize and iteratively develop a new workflow. Participants found our prototypes fast and intuitive, the design clean and consistent, relevant information easy to access, and the request process fast and easy. Due to the COVID pandemic, we switched to remote prototype testing, which yielded equally good feedback and increased the participation rate. In the end, we propose best practices for remote prototype testing in hospitals with complex and distributed workflows.}, address = {New York, NY, USA}, author = {Krop, Philipp and Straka, Samantha and Ullrich, Melanie and Ertl, Maximilian and Latoschik, Marc Erich}, booktitle = {CHI Conference on Human Factors in Computing Systems Extended Abstracts}, keywords = {straka}, month = {April}, number = 45, pages = {1-8}, publisher = {Association for Computing Machinery}, series = {CHI EA '22}, title = {IT-Supported Request Management for Clinical Radiology: Contextual Design and Remote Prototype Testing}, year = 2022 }
Towards a Cryptography Benchmark: A View on Attribute Based Encryption Schemes Prantl, Thomas; Zeck, Timo; Iffländer, Lukas; Beierlieb, Lukas; Dmitrenko, Alexandra; Krupitzer, Christian; Kounev, Samuel in 2022 5th Conference on Cloud and Internet of Things (CIoT) (2022).
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@inproceedings{PrZeIfBeDmKrKo2022-CIoT-ABEBenchmark, author = {Prantl, Thomas and Zeck, Timo and Iffländer, Lukas and Beierlieb, Lukas and Dmitrenko, Alexandra and Krupitzer, Christian and Kounev, Samuel}, booktitle = {2022 5th Conference on Cloud and Internet of Things (CIoT)}, keywords = {myown}, organization = {IEEE}, title = {Towards a Cryptography Benchmark: A View on Attribute Based Encryption Schemes}, year = 2022 }
ML-based Performance Prediction of SDN using Simulated Data from Real and Synthetic Networks Dietz, Katharina; Gray, Nicholas; Seufert, Michael; Hoßfeld, Tobias in 33th IEEE/IFIP Network Operations and Management Symposium (NOMS) (2022).
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@inproceedings{info3-inproceedings-2022-2, address = {Budapest, Hungary}, author = {Dietz, Katharina and Gray, Nicholas and Seufert, Michael and Hoßfeld, Tobias}, booktitle = {33th IEEE/IFIP Network Operations and Management Symposium (NOMS)}, keywords = {ucn}, month = 4, title = {ML-based Performance Prediction of SDN using Simulated Data from Real and Synthetic Networks}, year = 2022 }
Exploring Presence, Avatar Embodiment, and Body Perception with a Holographic Augmented Reality Mirror Wolf, Erik; Fiedler, Marie Luisa; Döllinger, Nina; Wienrich, Carolin; Latoschik, Marc Erich in 2022 IEEE Conference on Virtual Reality and 3D User Interfaces (VR) (2022). 350–359.
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The embodiment of avatars in virtual reality (VR) is a promising tool for enhancing the user's mental health. A great example is the treatment of body image disturbances, where eliciting a full-body illusion can help identify, visualize, and modulate persisting misperceptions. Augmented reality (AR) could complement recent advances in the field by incorporating real elements, such as the therapist or the user's real body, into therapeutic scenarios. However, research on the use of AR in this context is very sparse. Therefore, we present a holographic AR mirror system based on an optical see-through (OST) device and markerless body tracking, collect valuable qualitative feedback regarding its user experience, and compare quantitative results regarding presence, embodiment, and body weight perception to similar systems using video see-through (VST) AR and VR. For our OST AR system, a total of 27 normal-weight female participants provided predominantly positive feedback on display properties (field of view, luminosity, and transparency of virtual objects), body tracking, and the perception of the avatar’s appearance and movements. In the quantitative comparison to the VST AR and VR systems, participants reported significantly lower feelings of presence, while they estimated the body weight of the generic avatar significantly higher when using our OST AR system. For virtual body ownership and agency, we found only partially significant differences. In summary, our study shows the general applicability of OST AR in the given context offering huge potential in future therapeutic scenarios. However, the comparative evaluation between OST AR, VST AR, and VR also revealed significant differences in relevant measures. Future work is mandatory to corroborate our findings and to classify the significance in a therapeutic context.

@inproceedings{wolf2022holographic, abstract = {The embodiment of avatars in virtual reality (VR) is a promising tool for enhancing the user's mental health. A great example is the treatment of body image disturbances, where eliciting a full-body illusion can help identify, visualize, and modulate persisting misperceptions. Augmented reality (AR) could complement recent advances in the field by incorporating real elements, such as the therapist or the user's real body, into therapeutic scenarios. However, research on the use of AR in this context is very sparse. Therefore, we present a holographic AR mirror system based on an optical see-through (OST) device and markerless body tracking, collect valuable qualitative feedback regarding its user experience, and compare quantitative results regarding presence, embodiment, and body weight perception to similar systems using video see-through (VST) AR and VR. For our OST AR system, a total of 27 normal-weight female participants provided predominantly positive feedback on display properties (field of view, luminosity, and transparency of virtual objects), body tracking, and the perception of the avatar’s appearance and movements. In the quantitative comparison to the VST AR and VR systems, participants reported significantly lower feelings of presence, while they estimated the body weight of the generic avatar significantly higher when using our OST AR system. For virtual body ownership and agency, we found only partially significant differences. In summary, our study shows the general applicability of OST AR in the given context offering huge potential in future therapeutic scenarios. However, the comparative evaluation between OST AR, VST AR, and VR also revealed significant differences in relevant measures. Future work is mandatory to corroborate our findings and to classify the significance in a therapeutic context.}, author = {Wolf, Erik and Fiedler, Marie Luisa and Döllinger, Nina and Wienrich, Carolin and Latoschik, Marc Erich}, booktitle = {2022 IEEE Conference on Virtual Reality and 3D User Interfaces (VR)}, keywords = {vitras}, pages = {350-359}, title = {Exploring Presence, Avatar Embodiment, and Body Perception with a Holographic Augmented Reality Mirror}, year = 2022 }
Classroom management competency enhancement for student teachers using a fully immersive virtual classroom Seufert, Christian; Oberd{\"o}rfer, Sebastian; Roth, Alice; Grafe, Silke; Lugrin, Jean-Luc; Latoschik, Marc Erich in Computers & Education (2022). 179 104410.
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The purpose of this study is to examine whether pre-service teachers studying classroom management (CM) in a virtual reality (VR)-supported setting enhance their CM competencies more than students do in a setting using conventional methods. With this aim in mind and to address a lack of available situations of practicing and reflecting CM competencies besides simply gaining theoretical knowledge about CM in education, we integrated a novel fully immersive VR application in selected CM courses. We evaluated the development of self-assessed and instructor-rated CM competencies and the learning quality in the different learning conditions. Additionally, we evaluated the presence, social presence, believability and utility of the VR application and the VR-assisted and video-assisted course. Participants were pre-service teachers (n = 55) of the University of W{\"u}rzburg who participated in a quasi-experimental pre-test/post-test intervention. The students were randomly assigned to one of two intervention groups: the test group used the virtual classroom Breaking Bad Behaviors (BBB) during the term (n = 39), and the comparison group's learning was video-assisted (n = 16). The instructor rating shows significant differences between the VR group and the video group, the two points of measurement and for the interaction between the condition and time of measurement. It demonstrates a highly significant improvement in CM competencies in the VR setting between the pre-test and post-test (p < 0.001, Cohen's d = 1.06) as compared to the video-based setting. The participants of the VR setting themselves rated their CM competencies in the post-test significantly higher than in the pre-test (p = 0.02, Cohen's d = 0.39). Interestingly, the video group also rated themselves better in the post-test (p = 0.02, Cohen's d = 0.67), which reveals that self-assessment and external assessment show different results. In addition, we observed that even if both groups gained similar theoretical knowledge, the CM competencies developed to a greater degree in the VR-based settings. The participants rated the CM training system a useful tool to evaluate and reflect on individual teacher actions. Its immersion contributes to a high presence and the simulation of realistic scenarios in a CM course. These findings suggest that VR-based settings can lead to a higher benefit in the enhancement of pre-service teachers' CM competencies.

@article{seufert:2022n, abstract = {The purpose of this study is to examine whether pre-service teachers studying classroom management (CM) in a virtual reality (VR)-supported setting enhance their CM competencies more than students do in a setting using conventional methods. With this aim in mind and to address a lack of available situations of practicing and reflecting CM competencies besides simply gaining theoretical knowledge about CM in education, we integrated a novel fully immersive VR application in selected CM courses. We evaluated the development of self-assessed and instructor-rated CM competencies and the learning quality in the different learning conditions. Additionally, we evaluated the presence, social presence, believability and utility of the VR application and the VR-assisted and video-assisted course. Participants were pre-service teachers (n = 55) of the University of W{\"u}rzburg who participated in a quasi-experimental pre-test/post-test intervention. The students were randomly assigned to one of two intervention groups: the test group used the virtual classroom Breaking Bad Behaviors (BBB) during the term (n = 39), and the comparison group's learning was video-assisted (n = 16). The instructor rating shows significant differences between the VR group and the video group, the two points of measurement and for the interaction between the condition and time of measurement. It demonstrates a highly significant improvement in CM competencies in the VR setting between the pre-test and post-test (p < 0.001, Cohen's d = 1.06) as compared to the video-based setting. The participants of the VR setting themselves rated their CM competencies in the post-test significantly higher than in the pre-test (p = 0.02, Cohen's d = 0.39). Interestingly, the video group also rated themselves better in the post-test (p = 0.02, Cohen's d = 0.67), which reveals that self-assessment and external assessment show different results. In addition, we observed that even if both groups gained similar theoretical knowledge, the CM competencies developed to a greater degree in the VR-based settings. The participants rated the CM training system a useful tool to evaluate and reflect on individual teacher actions. Its immersion contributes to a high presence and the simulation of realistic scenarios in a CM course. These findings suggest that VR-based settings can lead to a higher benefit in the enhancement of pre-service teachers' CM competencies.}, author = {Seufert, Christian and Oberd{\"o}rfer, Sebastian and Roth, Alice and Grafe, Silke and Lugrin, Jean-Luc and Latoschik, Marc Erich}, journal = {Computers & Education}, keywords = {virtual}, pages = 104410, title = {Classroom management competency enhancement for student teachers using a fully immersive virtual classroom}, volume = 179, year = 2022 }
Interactive, Visual Simulation of a Spatio-Temporal Model of Gas Exchange in the Human Alveolus Schmid, Kerstin; Knote, Andreas; Mück, Alexander; Pfeiffer, Keram; von Mammen, Sebastian; Fischer, Sabine C. in Frontiers in Bioinformatics (2022). 1
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In interdisciplinary fields such as systems biology, good communication between experimentalists and theorists is crucial for the success of a project. Theoretical modeling in physiology usually describes complex systems with many interdependencies. On one hand, these models have to be grounded on experimental data. On the other hand, experimenters must be able to understand the interdependent complexities of the theoretical model in order to interpret the model’s results in the physiological context. We promote interactive, visual simulations as an engaging way to present theoretical models in physiology and to make complex processes tangible. Based on a requirements analysis, we developed a new model for gas exchange in the human alveolus in combination with an interactive simulation software named Alvin. Alvin exceeds the current standard with its spatio-temporal resolution and a combination of visual and quantitative feedback. In Alvin, the course of the simulation can be traced in a three-dimensional rendering of an alveolus and dynamic plots. The user can interact by configuring essential model parameters. Alvin allows to run and compare multiple simulation instances simultaneously. We exemplified the use of Alvin for research by identifying unknown dependencies in published experimental data. Employing a detailed questionnaire, we showed the benefits of Alvin for education. We postulate that interactive, visual simulation of theoretical models, as we have implemented with Alvin on respiratory processes in the alveolus, can be of great help for communication between specialists and thereby advancing research.

@article{10.3389/fbinf.2021.774300, abstract = {In interdisciplinary fields such as systems biology, good communication between experimentalists and theorists is crucial for the success of a project. Theoretical modeling in physiology usually describes complex systems with many interdependencies. On one hand, these models have to be grounded on experimental data. On the other hand, experimenters must be able to understand the interdependent complexities of the theoretical model in order to interpret the model’s results in the physiological context. We promote interactive, visual simulations as an engaging way to present theoretical models in physiology and to make complex processes tangible. Based on a requirements analysis, we developed a new model for gas exchange in the human alveolus in combination with an interactive simulation software named Alvin. Alvin exceeds the current standard with its spatio-temporal resolution and a combination of visual and quantitative feedback. In Alvin, the course of the simulation can be traced in a three-dimensional rendering of an alveolus and dynamic plots. The user can interact by configuring essential model parameters. Alvin allows to run and compare multiple simulation instances simultaneously. We exemplified the use of Alvin for research by identifying unknown dependencies in published experimental data. Employing a detailed questionnaire, we showed the benefits of Alvin for education. We postulate that interactive, visual simulation of theoretical models, as we have implemented with Alvin on respiratory processes in the alveolus, can be of great help for communication between specialists and thereby advancing research.}, author = {Schmid, Kerstin and Knote, Andreas and Mück, Alexander and Pfeiffer, Keram and von Mammen, Sebastian and Fischer, Sabine C.}, journal = {Frontiers in Bioinformatics}, keywords = {myown}, title = {Interactive, Visual Simulation of a Spatio-Temporal Model of Gas Exchange in the Human Alveolus}, volume = 1, year = 2022 }
SCRAPS: Scalable Collective Remote Attestation for Pub-Sub IoT Networks with Untrusted Proxy Verifier Petzi, Lukas; Ben Yahya, Ala Eddine; Dmitrienko, Alexandra; Tsudik, Gene; Prantl, Thomas; Kounev, Samuel (2022). (Vol. USENIX Security ’22)
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Remote Attestation (RA) is a basic security mechanism that detects malicious presence on various types of computing components, e.g., IoT devices. In a typical IoT setting, RA involves a trusted Verifier that sends a challenge to an untrusted remote Prover, which must in turn reply with a fresh and authentic evidence of being in a trustworthy state. However,most current RA schemes assume a central Verifier, which rep-resents a single point of failure. This feature is problematic when mutually suspicious stakeholders are involved. Furthermore, scalability issues arise as the number of IoT devices (Provers) grows. Although some RA schemes allow peer Provers to act as Verifiers, they involve unrealistic (for IoT devices) requirements, such as time synchronization and synchronous communication. Moreover, they incur heavy memory, computation,and communication burdens, while not considering sleeping or otherwise disconnected devices. Motivated by the need to address these limitations, we construct Scalable Collective Remote Attestation for Pub-Sub (SCRAPS), a novel collective RA scheme. It achieves scalability by outsourcing Verifier duties to a smart contract and mitigates DoS attacks against both Provers and Verifiers. It also removes the need for synchronous communication. Furthermore,RA evidence in SCRAPS is publicly verifiable, which significantly reduces the number of attestation evidence computations, thus lowering Prover burden. We report on a prototype of SCRAPS over Hyperledger Sawtooth (a blockchain geared for IoT use-cases) and evaluate its performance, scalability, and security aspects.

@proceedings{petzi2022scraps, abstract = {Remote Attestation (RA) is a basic security mechanism that detects malicious presence on various types of computing components, e.g., IoT devices. In a typical IoT setting, RA involves a trusted Verifier that sends a challenge to an untrusted remote Prover, which must in turn reply with a fresh and authentic evidence of being in a trustworthy state. However,most current RA schemes assume a central Verifier, which rep-resents a single point of failure. This feature is problematic when mutually suspicious stakeholders are involved. Furthermore, scalability issues arise as the number of IoT devices (Provers) grows. Although some RA schemes allow peer Provers to act as Verifiers, they involve unrealistic (for IoT devices) requirements, such as time synchronization and synchronous communication. Moreover, they incur heavy memory, computation,and communication burdens, while not considering sleeping or otherwise disconnected devices. Motivated by the need to address these limitations, we construct Scalable Collective Remote Attestation for Pub-Sub (SCRAPS), a novel collective RA scheme. It achieves scalability by outsourcing Verifier duties to a smart contract and mitigates DoS attacks against both Provers and Verifiers. It also removes the need for synchronous communication. Furthermore,RA evidence in SCRAPS is publicly verifiable, which significantly reduces the number of attestation evidence computations, thus lowering Prover burden. We report on a prototype of SCRAPS over Hyperledger Sawtooth (a blockchain geared for IoT use-cases) and evaluate its performance, scalability, and security aspects.}, author = {Petzi, Lukas and Ben Yahya, Ala Eddine and Dmitrienko, Alexandra and Tsudik, Gene and Prantl, Thomas and Kounev, Samuel}, keywords = {myown}, note = {Coming Soon}, title = {SCRAPS: Scalable Collective Remote Attestation for Pub-Sub IoT Networks with Untrusted Proxy Verifier}, volume = {USENIX Security '22}, year = 2022 }
Virtual Human Coherence and Plausibility – Towards a Validated Scale Mal, David; Wolf, Erik; Döllinger, Nina; Botsch, Mario; Wienrich, Carolin; Latoschik, Marc Erich in Proceedings of the 29th IEEE Conference on Virtual Reality and 3D User Interfaces Abstracts and Workshops (VR ’22) (2022). 788–789.
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Virtual humans contribute to users’ state of plausibility in various XR applications. We present the development and preliminary evaluation of a self-assessment questionnaire to quantify virtual human’s plausibility in virtual environments based on eleven concise items. A principal component analysis of 650 appraisals collected in an online survey revealed two highly reliable components within the items. We interpret the components as possible factors, i.e., appearance and behavior plausibility and match to the virtual environment, and propose future work aiming towards a standardized virtual human plausibility scale by validating the structure and sensitivity of both sub-components in XR environments.

@inproceedings{mal2022virtual, abstract = {Virtual humans contribute to users’ state of plausibility in various XR applications. We present the development and preliminary evaluation of a self-assessment questionnaire to quantify virtual human’s plausibility in virtual environments based on eleven concise items. A principal component analysis of 650 appraisals collected in an online survey revealed two highly reliable components within the items. We interpret the components as possible factors, i.e., appearance and behavior plausibility and match to the virtual environment, and propose future work aiming towards a standardized virtual human plausibility scale by validating the structure and sensitivity of both sub-components in XR environments.}, author = {Mal, David and Wolf, Erik and Döllinger, Nina and Botsch, Mario and Wienrich, Carolin and Latoschik, Marc Erich}, booktitle = {Proceedings of the 29th IEEE Conference on Virtual Reality and 3D User Interfaces Abstracts and Workshops (VR '22)}, keywords = {vitras}, pages = {788-789}, title = {Virtual Human Coherence and Plausibility – Towards a Validated Scale}, year = 2022 }
Stay Safe! Safety Precautions for Walking on a Conventional Treadmill in VR Birnstiel, Sandra; Oberdörfer, Sebastian; Latoschik, Marc Erich in Proceedings of the 29th IEEE Conference on Virtual Reality and 3D User Interfaces Abstracts and Workshops (VR ’22) (2022). 732–733.
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Conventional treadmills are used in virtual reality (VR) applications, such as for rehabilitation training or gait studies. However, using the devices in VR poses risks of injury. Therefore, this study investigates safety precautions when using a conventional treadmill for a walking task. We designed a safety belt and displayed parts of the treadmill in VR. The safety belt was much appreciated by the participants and did not affect the walking behavior. However, the participants requested more visual cues in the user’s field of view.

@inproceedings{birnstiel2022safety, abstract = {Conventional treadmills are used in virtual reality (VR) applications, such as for rehabilitation training or gait studies. However, using the devices in VR poses risks of injury. Therefore, this study investigates safety precautions when using a conventional treadmill for a walking task. We designed a safety belt and displayed parts of the treadmill in VR. The safety belt was much appreciated by the participants and did not affect the walking behavior. However, the participants requested more visual cues in the user’s field of view.}, author = {Birnstiel, Sandra and Oberdörfer, Sebastian and Latoschik, Marc Erich}, booktitle = {Proceedings of the 29th IEEE Conference on Virtual Reality and 3D User Interfaces Abstracts and Workshops (VR '22)}, keywords = {oberdoerfer}, organization = {IEEE}, pages = {732-733}, title = {Stay Safe! Safety Precautions for Walking on a Conventional Treadmill in VR}, year = 2022 }
Towards a Cryptography Benchmark: A View on Attribute Based Encryption Schemes Prantl, Thomas; Zeck, Timo; Iffländer, Lukas; Beierlieb, Lukas; Dmitrenko, Alexandra; Krupitzer, Christian; Kounev, Samuel in 2022 5th Conference on Cloud and Internet of Things (CIoT) (2022).
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@inproceedings{PrZeIfBeDmKrKo2022-CIoT-ABEBenchmark, author = {Prantl, Thomas and Zeck, Timo and Iffländer, Lukas and Beierlieb, Lukas and Dmitrenko, Alexandra and Krupitzer, Christian and Kounev, Samuel}, booktitle = {2022 5th Conference on Cloud and Internet of Things (CIoT)}, keywords = {myown}, organization = {IEEE}, title = {Towards a Cryptography Benchmark: A View on Attribute Based Encryption Schemes}, year = 2022 }
Towards a Cryptography Benchmark: A View on Attribute Based Encryption Schemes Prantl, Thomas; Zeck, Timo; Iffländer, Lukas; Beierlieb, Lukas; Dmitrenko, Alexandra; Krupitzer, Christian; Kounev, Samuel in 2022 5th Conference on Cloud and Internet of Things (CIoT) (2022).
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@inproceedings{PrZeIfBeDmKrKo2022-CIoT-ABEBenchmark, author = {Prantl, Thomas and Zeck, Timo and Iffländer, Lukas and Beierlieb, Lukas and Dmitrenko, Alexandra and Krupitzer, Christian and Kounev, Samuel}, booktitle = {2022 5th Conference on Cloud and Internet of Things (CIoT)}, keywords = {myown}, organization = {IEEE}, title = {Towards a Cryptography Benchmark: A View on Attribute Based Encryption Schemes}, year = 2022 }
Dense Feature Matching based on Homographic Decomposition Seibt, Simon; von Ramon Lipinski, Bartosz; Latoschik, March Erich in IEEE Access (2022). X 1–1.
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Finding robust and accurate feature matches is a fundamental problem in computer vision. However, incorrect correspondences and suboptimal matching accuracies lead to significant challenges for many real-world applications. In conventional feature matching, corresponding features in an image pair are greedily searched using their descriptor distance. The resulting matching set is then typically used as input for geometric model fitting methods to find an appropriate fundamental matrix and filter out incorrect matches. Unfortunately, this basic approach cannot solve all practical problems, such as fundamental matrix degeneration, matching ambiguities caused by repeated patterns and rejection of initially mismatched features without further reconsideration. In this paper we introduce a novel matching pipeline, which addresses all of the aforementioned challenges at once: First, we perform iterative rematching to give mismatched feature points a further chance for being considered in later processing steps. Thereby, we are searching for inliers that exhibit the same homographic transformation per iteration. The resulting homographic decomposition is used for refining matches, occlusion detection (e.g. due to parallaxes) and extrapolation of additional features in critical image areas. Furthermore, Delaunay triangulation of the matching set is utilized to minimize the repeated pattern problem and to implement focused matching. Doing so, enables us to further increase matching quality by concentrating on local image areas, defined by the triangular mesh. We present and discuss experimental results with multiple real-world matching datasets. Our contributions, besides improving matching recall and precision for image processing applications in general, also relate to use cases in image-based computer graphics.

@article{seibt2022dense, abstract = {Finding robust and accurate feature matches is a fundamental problem in computer vision. However, incorrect correspondences and suboptimal matching accuracies lead to significant challenges for many real-world applications. In conventional feature matching, corresponding features in an image pair are greedily searched using their descriptor distance. The resulting matching set is then typically used as input for geometric model fitting methods to find an appropriate fundamental matrix and filter out incorrect matches. Unfortunately, this basic approach cannot solve all practical problems, such as fundamental matrix degeneration, matching ambiguities caused by repeated patterns and rejection of initially mismatched features without further reconsideration. In this paper we introduce a novel matching pipeline, which addresses all of the aforementioned challenges at once: First, we perform iterative rematching to give mismatched feature points a further chance for being considered in later processing steps. Thereby, we are searching for inliers that exhibit the same homographic transformation per iteration. The resulting homographic decomposition is used for refining matches, occlusion detection (e.g. due to parallaxes) and extrapolation of additional features in critical image areas. Furthermore, Delaunay triangulation of the matching set is utilized to minimize the repeated pattern problem and to implement focused matching. Doing so, enables us to further increase matching quality by concentrating on local image areas, defined by the triangular mesh. We present and discuss experimental results with multiple real-world matching datasets. Our contributions, besides improving matching recall and precision for image processing applications in general, also relate to use cases in image-based computer graphics.}, author = {Seibt, Simon and von Ramon Lipinski, Bartosz and Latoschik, March Erich}, journal = {IEEE Access}, keywords = {myown}, pages = {1-1}, title = {Dense Feature Matching based on Homographic Decomposition}, volume = {X}, year = 2022 }
Characterizing Mobile Signaling Anomalies in the Internet-of-Things Vomhoff, Viktoria; Geißler, Stefan; Loh, Frank; Bauer, Wolfgang; Hoßfeld, Tobias in 2nd IFIP/IEEE International workshop on Fully-Flexible Internet Architectures and Protocols for the Next-Generation Tactile Internet (FlexNGIA) (2022).
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The development and adoption speed of new Internet of Things (IoT) devices and applications is constantly increasing. In particular in mobile networks, however, constant connectivity for all newly developed, globally spread, and occasionally geographically mobile devices is challenging. While the main business of current network operators is in particular, not to roam these new device generation between different networks, whereas new so-called Mobile Virtual Network Operators (MVNOs) arise with exactly this business case. They use already available Radio Access Networks and deploy SIM cards that are able to establish data connection everywhere on the basis of international roaming agreements. However, because of the complex interconnection of different systems, additional challenges arise. Outages in one network component might impact the whole system. In this work, we study these signaling anomalies called incidents based on a dataset received from a global MVNO. The goal of this work is to determine traffic characteristics during these incidents towards a better understanding of signaling traffic in IoT networks. Thus, this work can be seen as a fundamental basis to help operators in a characterization, and in particular prediction and avoidance of signaling incidents.

@inproceedings{info3-inproceedings-2022-4, abstract = {The development and adoption speed of new Internet of Things (IoT) devices and applications is constantly increasing. In particular in mobile networks, however, constant connectivity for all newly developed, globally spread, and occasionally geographically mobile devices is challenging. While the main business of current network operators is in particular, not to roam these new device generation between different networks, whereas new so-called Mobile Virtual Network Operators (MVNOs) arise with exactly this business case. They use already available Radio Access Networks and deploy SIM cards that are able to establish data connection everywhere on the basis of international roaming agreements. However, because of the complex interconnection of different systems, additional challenges arise. Outages in one network component might impact the whole system. In this work, we study these signaling anomalies called incidents based on a dataset received from a global MVNO. The goal of this work is to determine traffic characteristics during these incidents towards a better understanding of signaling traffic in IoT networks. Thus, this work can be seen as a fundamental basis to help operators in a characterization, and in particular prediction and avoidance of signaling incidents.}, author = {Vomhoff, Viktoria and Geißler, Stefan and Loh, Frank and Bauer, Wolfgang and Hoßfeld, Tobias}, booktitle = {2nd IFIP/IEEE International workshop on Fully-Flexible Internet Architectures and Protocols for the Next-Generation Tactile Internet (FlexNGIA)}, keywords = {can}, month = 4, title = {Characterizing Mobile Signaling Anomalies in the Internet-of-Things}, year = 2022 }
Breaking Plausibility Without Breaking Presence - Evidence For The Multi-Layer Nature Of Plausibility Brübach, Larissa; Westermeier, Franziska; Wienrich, Carolin; Latoschik, Marc Erich in IEEE Transactions on Visualization and Computer Graphics (2022). 28(5) 2267–2276.
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A novel theoretical model recently introduced coherence and plausibility as the essential conditions of XR experiences, challenging contemporary presence-oriented concepts. This article reports on two experiments validating this model, which assumes coherence activation on three layers (cognition, perception, and sensation) as the potential sources leading to a condition of plausibility and from there to other XR qualia such as presence or body ownership. The experiments introduce and utilize breaks in plausibility (in analogy to breaks in presence): We induce incoherence on the perceptual and the cognitive layer simultaneously by a simulation of object behaviors that do not conform to the laws of physics, i.e., gravity. We show that this manipulation breaks plausibility and hence confirm that it results in the desired effects in the theorized condition space but that the breaks in plausibility did not affect presence. In addition, we show that a cognitive manipulation by a storyline framing is too weak to successfully counteract the strong bottom-up inconsistencies. Both results are in line with the predictions of the recently introduced three-layer model of coherence and plausibility, which incorporates well-known top-down and bottom-up rivalries and its theorized increased independence between plausibility and presence.

@article{9714117, abstract = {A novel theoretical model recently introduced coherence and plausibility as the essential conditions of XR experiences, challenging contemporary presence-oriented concepts. This article reports on two experiments validating this model, which assumes coherence activation on three layers (cognition, perception, and sensation) as the potential sources leading to a condition of plausibility and from there to other XR qualia such as presence or body ownership. The experiments introduce and utilize breaks in plausibility (in analogy to breaks in presence): We induce incoherence on the perceptual and the cognitive layer simultaneously by a simulation of object behaviors that do not conform to the laws of physics, i.e., gravity. We show that this manipulation breaks plausibility and hence confirm that it results in the desired effects in the theorized condition space but that the breaks in plausibility did not affect presence. In addition, we show that a cognitive manipulation by a storyline framing is too weak to successfully counteract the strong bottom-up inconsistencies. Both results are in line with the predictions of the recently introduced three-layer model of coherence and plausibility, which incorporates well-known top-down and bottom-up rivalries and its theorized increased independence between plausibility and presence.}, author = {Brübach, Larissa and Westermeier, Franziska and Wienrich, Carolin and Latoschik, Marc Erich}, journal = {IEEE Transactions on Visualization and Computer Graphics}, keywords = {myown}, month = {feb}, note = {IEEE VR Best Journal Paper Nominee 🏆}, number = 5, pages = {2267-2276}, title = {Breaking Plausibility Without Breaking Presence - Evidence For The Multi-Layer Nature Of Plausibility}, volume = 28, year = 2022 }
Remote at Court – Challenges and Solutions of Video Conferencing in the Judicial System Wienrich, Carolin; Fries, Lennart; Latoschik, Marc Erich in Proceedings 25th HCI International Conference (2022). (Vol. Design, Operation and Evaluation of Mobile Communications) 82–106.
- [ BibTeX ]
@inproceedings{wienrich2022remote, author = {Wienrich, Carolin and Fries, Lennart and Latoschik, Marc Erich}, booktitle = {Proceedings 25th HCI International Conference}, keywords = {myown}, pages = {82-106}, publisher = {Springer}, title = {Remote at Court – Challenges and Solutions of Video Conferencing in the Judicial System}, volume = {Design, Operation and Evaluation of Mobile Communications}, year = 2022 }
Inter- and Transcultural Learning in Social Virtual Reality: A Proposal for an Inter- and Transcultural Virtual Object Database to be Used in the Implementation, Reflection, and Evaluation of Virtual Encounters Hein, Rebecca M.; Latoschik, Marc Erich; Wienrich, Carolin in Multimodal Technologies and Interaction, (F. L. {Mark Billinghurst; M.-C. Su, eds.) (2022). 6(7) 50.
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Visual stimuli are frequently used to improve memory, language learning or perception, and understanding of metacognitive processes. However, in virtual reality (VR), there are few systematically and empirically derived databases. This paper proposes the first collection of virtual objects based on empirical evaluation for inter-and transcultural encounters between English- and German-speaking learners. We used explicit and implicit measurement methods to identify cultural associations and the degree of stereotypical perception for each virtual stimuli (n = 293) through two online studies, including native German and English-speaking participants. The analysis resulted in a final well-describable database of 128 objects (called InteractionSuitcase). In future applications, the objects can be used as a great interaction or conversation asset and behavioral measurement tool in social VR applications, especially in the field of foreign language education. For example, encounters can use the objects to describe their culture, or teachers can intuitively assess stereotyped attitudes of the encounters.

@article{mti6070050, abstract = {Visual stimuli are frequently used to improve memory, language learning or perception, and understanding of metacognitive processes. However, in virtual reality (VR), there are few systematically and empirically derived databases. This paper proposes the first collection of virtual objects based on empirical evaluation for inter-and transcultural encounters between English- and German-speaking learners. We used explicit and implicit measurement methods to identify cultural associations and the degree of stereotypical perception for each virtual stimuli (n = 293) through two online studies, including native German and English-speaking participants. The analysis resulted in a final well-describable database of 128 objects (called InteractionSuitcase). In future applications, the objects can be used as a great interaction or conversation asset and behavioral measurement tool in social VR applications, especially in the field of foreign language education. For example, encounters can use the objects to describe their culture, or teachers can intuitively assess stereotyped attitudes of the encounters.}, author = {Hein, Rebecca M. and Latoschik, Marc Erich and Wienrich, Carolin}, editor = {{Mark Billinghurst, Fotis Liarokapis}, Lars Erik Holmquist and Su, Mu-Chun}, journal = {Multimodal Technologies and Interaction}, keywords = {rhein}, number = 7, pages = 50, title = {Inter- and Transcultural Learning in Social Virtual Reality: A Proposal for an Inter- and Transcultural Virtual Object Database to be Used in the Implementation, Reflection, and Evaluation of Virtual Encounters}, volume = 6, year = 2022 }
Comparing Traditional and GAN-based Approaches for the Synthesis of Wide Area Network Topologies Dietz, Katharina; Seufert, Michael; Hoßfeld, Tobias in 18th International Conference on Network and Service Management (CNSM) (2022).
- [ BibTeX ]
@inproceedings{info3-inproceedings-2022-16, address = {Thessaloniki, Greece}, author = {Dietz, Katharina and Seufert, Michael and Hoßfeld, Tobias}, booktitle = {18th International Conference on Network and Service Management (CNSM)}, keywords = {ucn}, month = 10, title = {Comparing Traditional and GAN-based Approaches for the Synthesis of Wide Area Network Topologies}, year = 2022 }
Who is Alyx? Schell, Christian; Sieper, Fabian; Latoschik, Marc E. (2022, April).
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This dataset contains over 57 hours of motion and eye-tracking data from 37 players of the virtual reality game "Half-Life: Alyx". Each player played the game on two separate days for about 45 minutes using a HTC Vive Pro.

@dataset{who_is_alyx_2022, abstract = {This dataset contains over 57 hours of motion and eye-tracking data from 37 players of the virtual reality game "Half-Life: Alyx". Each player played the game on two separate days for about 45 minutes using a HTC Vive Pro.}, author = {Schell, Christian and Sieper, Fabian and Latoschik, Marc E.}, keywords = {prima}, month = {April}, title = {Who is Alyx?}, year = 2022 }
{Real-Time Music-Driven Movie Design Framework} Hofmann, Sarah; Seeger, Maximilian; Rogge-Pott, Henning; Mammen, Sebastian von in Workshop on Intelligent Cinematography and Editing, R. Ronfard, H.-Y. Wu (eds.) (2022).
- [ BibTeX ]
- [ URL ]
@inproceedings{10.2312:wiced.20221052, author = {Hofmann, Sarah and Seeger, Maximilian and Rogge-Pott, Henning and Mammen, Sebastian von}, booktitle = {Workshop on Intelligent Cinematography and Editing}, editor = {Ronfard, Rémi and Wu, Hui-Yin}, keywords = {myown}, publisher = {The Eurographics Association}, title = {{Real-Time Music-Driven Movie Design Framework}}, year = 2022 }
Not all Web Pages are Born the Same. Content Tailored Learning for Web QoE Inference Casas, Pedro; Wassermann, Sarah; Wehner, Nikolas; Seufert, Michael; Hoßfeld, Tobias in IEEE International Symposium on Measurements & Networking (M&N 2022) (2022).
- [ Abstract ]
- [ BibTeX ]
Web Quality of Experience (QoE) monitoring is a critical task for Internet Service Providers (ISPs), especially due to the key role played by customer experience in churn management. Previously, we have tackled the problem of Web QoE inference from the ISP perspective, relying on passive measurement of encrypted network traffic and machine learning models. In this paper, we exploit the broad heterogeneity of contents embedded in web pages to improve the state of the art performance in Web QoE inference, relying on web-content learning model tailoring. By analyzing the top-500 most popular web pages of the Internet through unsupervised learning, we discover different web page content classes which realize significantly different Web QoE inference performance. We train supervised learning inference models separately for each of these classes, using the well-known Speed Index (SI) metric as proxy to Web QoE. Empirical evaluations on a large corpus of Web QoE measurements for top popular websites demonstrate that our combined content-tailored approach improves the inference performance of the SI by almost 30% with respect to previous single-model approaches, reducing the QoE inference error in terms of mean opinion scores by more than 40%.

@inproceedings{info3-inproceedings-2022-10, abstract = {Web Quality of Experience (QoE) monitoring is a critical task for Internet Service Providers (ISPs), especially due to the key role played by customer experience in churn management. Previously, we have tackled the problem of Web QoE inference from the ISP perspective, relying on passive measurement of encrypted network traffic and machine learning models. In this paper, we exploit the broad heterogeneity of contents embedded in web pages to improve the state of the art performance in Web QoE inference, relying on web-content learning model tailoring. By analyzing the top-500 most popular web pages of the Internet through unsupervised learning, we discover different web page content classes which realize significantly different Web QoE inference performance. We train supervised learning inference models separately for each of these classes, using the well-known Speed Index (SI) metric as proxy to Web QoE. Empirical evaluations on a large corpus of Web QoE measurements for top popular websites demonstrate that our combined content-tailored approach improves the inference performance of the SI by almost 30% with respect to previous single-model approaches, reducing the QoE inference error in terms of mean opinion scores by more than 40%.}, author = {Casas, Pedro and Wassermann, Sarah and Wehner, Nikolas and Seufert, Michael and Hoßfeld, Tobias}, booktitle = {IEEE International Symposium on Measurements & Networking (M&N 2022)}, keywords = {myown}, month = 7, title = {Not all Web Pages are Born the Same. Content Tailored Learning for Web QoE Inference}, year = 2022 }
X-Ray Goggles for the ISP: Improving in-Network Web and App QoE Monitoring with Deep Learning Casas, Pedro; Wassermann, Sarah; Seufert, Michael; Wehner, Nikolas; Dinica, Olivia; Hoßfeld, Tobias in Network Traffic Measurement and Analysis Conference (TMA) (2022).
- [ Abstract ]
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The wide adoption of end-to-end encryption is drastically limiting the visibility Internet Service Providers (ISPs) have on the performance of the services consumed by their customers. In times of strong competition, where customer experience plays a key role in churn management, ISPs require novel solutions enabling network-wide Quality of Experience (QoE) monitoring. To this end, we present DeepQoE, a deep-learning based approach to infer the QoE of web services and mobile applications from the ISP perspective, relying exclusively on the analysis of encrypted network traffic. Using raw features derived from the encrypted stream of bytes as input to deep Convolutional Neural Networks (CNNs), DeepQoE infers the Speed Index of web browsing sessions and general mobile apps with unprecedented accuracy, improving the state of the art by more than 25%, and reducing the QoE inference error in terms of mean opinion scores by nearly 40%. DeepQoE implements a web fingerprinting solution to identify individual web browsing sessions within concurrent web pages traffic, enabling highly detailed, per web page QoE inference in practical deployments. Extensive evaluations over a large and heterogeneous dataset composed of web and app measurements, using different device types and for top-popular websites and apps, confirm the out-performance of DeepQoE over previously used shallow-learning models, as well as the deep-model generalization to different devices, web pages, apps, and network setups. DeepQoE is the first deployable system providing such a deep, highly-detailed QoE for individual web browsing and mobile apps over encrypted traffic, using deep learning models on heterogeneous measurements.

@inproceedings{info3-inproceedings-2022-11, abstract = {The wide adoption of end-to-end encryption is drastically limiting the visibility Internet Service Providers (ISPs) have on the performance of the services consumed by their customers. In times of strong competition, where customer experience plays a key role in churn management, ISPs require novel solutions enabling network-wide Quality of Experience (QoE) monitoring. To this end, we present DeepQoE, a deep-learning based approach to infer the QoE of web services and mobile applications from the ISP perspective, relying exclusively on the analysis of encrypted network traffic. Using raw features derived from the encrypted stream of bytes as input to deep Convolutional Neural Networks (CNNs), DeepQoE infers the Speed Index of web browsing sessions and general mobile apps with unprecedented accuracy, improving the state of the art by more than 25%, and reducing the QoE inference error in terms of mean opinion scores by nearly 40%. DeepQoE implements a web fingerprinting solution to identify individual web browsing sessions within concurrent web pages traffic, enabling highly detailed, per web page QoE inference in practical deployments. Extensive evaluations over a large and heterogeneous dataset composed of web and app measurements, using different device types and for top-popular websites and apps, confirm the out-performance of DeepQoE over previously used shallow-learning models, as well as the deep-model generalization to different devices, web pages, apps, and network setups. DeepQoE is the first deployable system providing such a deep, highly-detailed QoE for individual web browsing and mobile apps over encrypted traffic, using deep learning models on heterogeneous measurements.}, author = {Casas, Pedro and Wassermann, Sarah and Seufert, Michael and Wehner, Nikolas and Dinica, Olivia and Hoßfeld, Tobias}, booktitle = {Network Traffic Measurement and Analysis Conference (TMA)}, keywords = {myown}, month = 6, title = {X-Ray Goggles for the ISP: Improving in-Network Web and App QoE Monitoring with Deep Learning}, year = 2022 }
A literature review on optimization techniques for adaptation planning in adaptive systems: State of the art and research directions Henrichs, Elia; Lesch, Veronika; Straesser, Martin; Kounev, Samuel; Krupitzer, Christian in Information and Software Technology (2022). 149 106940.
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Context: Recent developments in modern IT systems including internet of things, edge/fog computing, or cyber–physical systems support intelligent and seamless interaction between users and systems. This requires a reaction to changes in their environment or the system. Adaptive systems provide mechanisms for these reactions. Objective: To implement this functionality, several approaches for the planning of adaptations exist that rely on rules, utility functions, or advanced techniques, such as machine learning. As the adaptation space with possible options is often extensively huge, optimization techniques might support efficient determination of the adaptation space and identify the system’s optimal configuration. With this paper, we provide a systematic review of adaptation planning as the optimization target. Method: In this paper, we review which optimization techniques are applied for adaptation planning in adaptive systems using a systematic literature review approach. Results: We reviewed 115 paper in detail out of an initial search set of 9,588 papers. Our analysis reveals that learning techniques and genetic algorithms are by far dominant; in total, heuristics (anytime learning) are more frequently applied as exact algorithms. We observed that around 57% of the approaches target multi-objectiveness and around 30% integrate distributed optimization. As last dimension, we focused on situation-awareness, which is only supported by two approaches. Conclusion: In this paper, we provide an overview of the current state of the art of approaches that rely on optimization techniques for planning adaptations in adaptive systems and further derive open research challenges, in particular regarding the integration of distributed optimization and situation-awareness.

@article{HENRICHS2022106940, abstract = {Context: Recent developments in modern IT systems including internet of things, edge/fog computing, or cyber–physical systems support intelligent and seamless interaction between users and systems. This requires a reaction to changes in their environment or the system. Adaptive systems provide mechanisms for these reactions. Objective: To implement this functionality, several approaches for the planning of adaptations exist that rely on rules, utility functions, or advanced techniques, such as machine learning. As the adaptation space with possible options is often extensively huge, optimization techniques might support efficient determination of the adaptation space and identify the system’s optimal configuration. With this paper, we provide a systematic review of adaptation planning as the optimization target. Method: In this paper, we review which optimization techniques are applied for adaptation planning in adaptive systems using a systematic literature review approach. Results: We reviewed 115 paper in detail out of an initial search set of 9,588 papers. Our analysis reveals that learning techniques and genetic algorithms are by far dominant; in total, heuristics (anytime learning) are more frequently applied as exact algorithms. We observed that around 57% of the approaches target multi-objectiveness and around 30% integrate distributed optimization. As last dimension, we focused on situation-awareness, which is only supported by two approaches. Conclusion: In this paper, we provide an overview of the current state of the art of approaches that rely on optimization techniques for planning adaptations in adaptive systems and further derive open research challenges, in particular regarding the integration of distributed optimization and situation-awareness.}, author = {Henrichs, Elia and Lesch, Veronika and Straesser, Martin and Kounev, Samuel and Krupitzer, Christian}, journal = {Information and Software Technology}, keywords = {myown}, pages = 106940, title = {A literature review on optimization techniques for adaptation planning in adaptive systems: State of the art and research directions}, volume = 149, year = 2022 }
A Vital Improvement? Relating Google’s Core Web Vitals to Actual Web QoE Wehner, Nikolas; Amir, Monisha; Seufert, Michael; Schatz, Raimund; Hoßfeld, Tobias in 14th International Conference on Quality of Multimedia Experience (QoMEX), Best Paper Award (2022).
- [ Abstract ]
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Providing sophisticated Web Quality of Experience (QoE) has become paramount for web service providers and network operators alike. Due to advances in Web technologies (HTML5, responsive design, etc.), traditional Web QoE models focusing mainly on loading times have to be refined and improved. In this work, we relate Google's Core Web Vitals, a set of metrics for improving user experience, to the loading time aspects of Web QoE. To this end, we first perform objective measurements in the Web using Google's Lighthouse. To close the gap between metrics and experience, we complement these objective measurements with subjective assessment by performing multiple crowdsourcing QoE studies. In these studies, we use CWeQS, a customized framework to emulate the entire web page loading process, and ask users for their experience while controlling the Core Web Vitals. Our results suggest that the Core Web Vitals have less predictive value for Web QoE than expected and that page loading times remain the main influence factor in this context.

@inproceedings{info3-inproceedings-2022-12, abstract = {Providing sophisticated Web Quality of Experience (QoE) has become paramount for web service providers and network operators alike. Due to advances in Web technologies (HTML5, responsive design, etc.), traditional Web QoE models focusing mainly on loading times have to be refined and improved. In this work, we relate Google's Core Web Vitals, a set of metrics for improving user experience, to the loading time aspects of Web QoE. To this end, we first perform objective measurements in the Web using Google's Lighthouse. To close the gap between metrics and experience, we complement these objective measurements with subjective assessment by performing multiple crowdsourcing QoE studies. In these studies, we use CWeQS, a customized framework to emulate the entire web page loading process, and ask users for their experience while controlling the Core Web Vitals. Our results suggest that the Core Web Vitals have less predictive value for Web QoE than expected and that page loading times remain the main influence factor in this context.}, address = {Lippstadt, Germany}, author = {Wehner, Nikolas and Amir, Monisha and Seufert, Michael and Schatz, Raimund and Hoßfeld, Tobias}, booktitle = {14th International Conference on Quality of Multimedia Experience (QoMEX), Best Paper Award}, keywords = {ucn}, month = 9, title = {A Vital Improvement? Relating Google's Core Web Vitals to Actual Web QoE}, year = 2022 }
An Introduction to Online Video Game QoS and QoE Influencing Factors Metzger, Florian; Geißler, Stefan; Grigorjew, Alexej; Loh, Frank; Moldovan, Christian; Seufert, Michael; Hoßfeld, Tobias in IEEE Communications Surveys & Tutorials (2022).
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Online video games and cloud gaming are rapidly growing in pervasiveness. Their resource demands can put significant stress on the global communication infrastructure. And network conditions are amongst the chief factors that influence one's enjoyment while playing games. This makes it imperative for video games to be considered for network dimensioning, server placement or protocol development. For that reason, in this work we provide an introduction to the technical aspects of video games in general and of their network aspects in particular. This understanding forms the basis for a rich taxonomy of factors that influence and provide context to a video game's Quality of Service (QoS) and Quality of Experience (QoE). The taxonomy covers influence factors from all aspects involved in a video game, from the subjective player and game influence factors to the system and networking influence factors. Finally, this work gives an overview of conducted and ongoing research as well as future research opportunities while taking into account lessons learned from past approaches.

@article{info3-article-2022-16, abstract = {Online video games and cloud gaming are rapidly growing in pervasiveness. Their resource demands can put significant stress on the global communication infrastructure. And network conditions are amongst the chief factors that influence one's enjoyment while playing games. This makes it imperative for video games to be considered for network dimensioning, server placement or protocol development. For that reason, in this work we provide an introduction to the technical aspects of video games in general and of their network aspects in particular. This understanding forms the basis for a rich taxonomy of factors that influence and provide context to a video game's Quality of Service (QoS) and Quality of Experience (QoE). The taxonomy covers influence factors from all aspects involved in a video game, from the subjective player and game influence factors to the system and networking influence factors. Finally, this work gives an overview of conducted and ongoing research as well as future research opportunities while taking into account lessons learned from past approaches.}, author = {Metzger, Florian and Geißler, Stefan and Grigorjew, Alexej and Loh, Frank and Moldovan, Christian and Seufert, Michael and Hoßfeld, Tobias}, journal = {IEEE Communications Surveys & Tutorials}, keywords = {10.1109/COMST.2022.3177251}, month = 5, title = {An Introduction to Online Video Game QoS and QoE Influencing Factors}, year = 2022 }
Fly My Little Dragon: Using AR to Learn Geometry Oberdörfer, Sebastian; Krop, Philipp; Straka, Samantha; Grafe, Silke; Latoschik, Marc Erich in Proceedings of the IEEE Conference on Games (CoG ’22) (2022). 528–531.
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We present the gamified AR learning environment ARES. During the gameplay, learners guide the little dragon called ”Ares” through dungeons. Using AR, ARES threedimensionally integrates the dungeons in the real-world. Each dungeon represents a coordinate system with obstacles that ultimately create mathematical exercises, e.g. rotating a door to let the dragon fly through it. Overcoming such a challenge requires a learner to spatially analyze the exercise and apply the fundamental mathematical principles. ARES displays a debriefing screen at the end of a dungeon to further support the learning process. In a preliminary qualitative user study, preservice and in-service teachers saw great potential in ARES for providing further practical and motivating exercises to deepen the knowledge in the classroom and at home.

@inproceedings{oberdorfer2022little, abstract = {We present the gamified AR learning environment ARES. During the gameplay, learners guide the little dragon called ”Ares” through dungeons. Using AR, ARES threedimensionally integrates the dungeons in the real-world. Each dungeon represents a coordinate system with obstacles that ultimately create mathematical exercises, e.g. rotating a door to let the dragon fly through it. Overcoming such a challenge requires a learner to spatially analyze the exercise and apply the fundamental mathematical principles. ARES displays a debriefing screen at the end of a dungeon to further support the learning process. In a preliminary qualitative user study, preservice and in-service teachers saw great potential in ARES for providing further practical and motivating exercises to deepen the knowledge in the classroom and at home.}, author = {Oberdörfer, Sebastian and Krop, Philipp and Straka, Samantha and Grafe, Silke and Latoschik, Marc Erich}, booktitle = {Proceedings of the IEEE Conference on Games (CoG '22)}, keywords = {oberdoerfer}, month = {August}, pages = {528-531}, publisher = {IEEE}, title = {Fly My Little Dragon: Using AR to Learn Geometry}, year = 2022 }
Waiting along the Path: How Browsing Delays Impact the QoE of Music Streaming Applications Seufert, Anika; Schweifler, Ralf; Poignée, Fabian; Seufert, Michael; Hoßfeld, Tobias in 14th International Conference on Quality of Multimedia Experience (QoMEX) (2022).
- [ Abstract ]
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Streaming has become the dominant source of media consumption, which not only applies to the widely researched field of video streaming, but also to music streaming. Here, previous studies so far have only researched the impact of streaming aspects, such as stalling events or initial loading times, on the QoE of music streaming. However, when using a music streaming application, users are already facing waiting times along the click path before they can start the actual streaming. These waiting times are caused by browsing delays, e.g., during searching for songs or scrolling through playlists, and can potentially deteriorate the QoE of the music streaming application. In this work, we conduct an online QoE study to quantify the impact of these browsing delays with the support of an emulated mobile music streaming web app. We found that browsing delays have no impact on the music streaming QoE, which shows that users are able to clearly distinguish between the two main functionalities of such apps, namely, browsing and streaming. However, browsing delays significantly reduce the QoE of the entire music streaming application, to a similar extent as if QoE degradations happen during the actual streaming. This shows that both browsing and streaming are equally important and have to be considered when designing music streaming applications.

@inproceedings{info3-inproceedings-2022-13, abstract = {Streaming has become the dominant source of media consumption, which not only applies to the widely researched field of video streaming, but also to music streaming. Here, previous studies so far have only researched the impact of streaming aspects, such as stalling events or initial loading times, on the QoE of music streaming. However, when using a music streaming application, users are already facing waiting times along the click path before they can start the actual streaming. These waiting times are caused by browsing delays, e.g., during searching for songs or scrolling through playlists, and can potentially deteriorate the QoE of the music streaming application. In this work, we conduct an online QoE study to quantify the impact of these browsing delays with the support of an emulated mobile music streaming web app. We found that browsing delays have no impact on the music streaming QoE, which shows that users are able to clearly distinguish between the two main functionalities of such apps, namely, browsing and streaming. However, browsing delays significantly reduce the QoE of the entire music streaming application, to a similar extent as if QoE degradations happen during the actual streaming. This shows that both browsing and streaming are equally important and have to be considered when designing music streaming applications.}, author = {Seufert, Anika and Schweifler, Ralf and Poignée, Fabian and Seufert, Michael and Hoßfeld, Tobias}, booktitle = {14th International Conference on Quality of Multimedia Experience (QoMEX)}, keywords = {myown}, month = 9, title = {Waiting along the Path: How Browsing Delays Impact the QoE of Music Streaming Applications}, year = 2022 }
Integration of a social robot and gamification in adult learning and effects on motivation, engagement and performance Riedmann, Anna; Schaper, Philipp; Lugrin, Birgit in AI & Society (2022).
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@article{Riedmann_2022, author = {Riedmann, Anna and Schaper, Philipp and Lugrin, Birgit}, journal = {AI & Society}, keywords = {schaper}, publisher = {Springer}, title = {Integration of a social robot and gamification in adult learning and effects on motivation, engagement and performance}, year = 2022 }
A Case Study on the Rapid Development of Natural and Synergistic Multimodal Interfaces for XR Use-Cases Zimmerer, Chris; Fischbach, Martin; Latoschik, Marc Erich in CHI Conference on Human Factors in Computing Systems Extended Abstracts, CHI EA ’22 (2022).
- [ Abstract ]
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- [ URL ]
Multimodal Interfaces (MMIs) supporting the synergistic use of natural modalities like speech and gesture have been conceived as promising for spatial or 3D interactions, e.g., in Virtual, Augmented, and Mixed Reality (XR for short). Yet, the currently prevailing user interfaces are unimodal. Commercially available software platforms like the Unity or Unreal game engines simplify the complexity of developing XR applications through appropriate tool support. They provide ready-to-use device integration, e.g., for 3D controllers or motion tracking, and according interaction techniques such as menus, (3D) point-and-click, or even simple symbolic gestures to rapidly develop unimodal interfaces. A comparable tool support is yet missing for multimodal solutions in this and similar areas. We believe that this hinders user-centered research based on rapid prototyping of MMIs, the identification and formulation of practical design guidelines, the development of killer applications highlighting the power of MMIs, and ultimately a widespread adoption of MMIs. This article investigates potential reasons for the ongoing uncommonness of MMIs. Our case study illustrates and analyzes lessons learned during the development and application of a toolchain that supports rapid development of natural and synergistic MMIs for XR use-cases. We analyze the toolchain in terms of developer usability, development time, and MMI customization. This analysis is based on the knowledge gained in years of research and academic education. Specifically, it reflects on the development of appropriate MMI tools and their application in various demo use-cases, in user-centered research, and in the lab work of a mandatory MMI course of an HCI master’s program. The derived insights highlight successful choices made as well as potential areas for improvement.

@inproceedings{10.1145/3491101.3503552, abstract = {Multimodal Interfaces (MMIs) supporting the synergistic use of natural modalities like speech and gesture have been conceived as promising for spatial or 3D interactions, e.g., in Virtual, Augmented, and Mixed Reality (XR for short). Yet, the currently prevailing user interfaces are unimodal. Commercially available software platforms like the Unity or Unreal game engines simplify the complexity of developing XR applications through appropriate tool support. They provide ready-to-use device integration, e.g., for 3D controllers or motion tracking, and according interaction techniques such as menus, (3D) point-and-click, or even simple symbolic gestures to rapidly develop unimodal interfaces. A comparable tool support is yet missing for multimodal solutions in this and similar areas. We believe that this hinders user-centered research based on rapid prototyping of MMIs, the identification and formulation of practical design guidelines, the development of killer applications highlighting the power of MMIs, and ultimately a widespread adoption of MMIs. This article investigates potential reasons for the ongoing uncommonness of MMIs. Our case study illustrates and analyzes lessons learned during the development and application of a toolchain that supports rapid development of natural and synergistic MMIs for XR use-cases. We analyze the toolchain in terms of developer usability, development time, and MMI customization. This analysis is based on the knowledge gained in years of research and academic education. Specifically, it reflects on the development of appropriate MMI tools and their application in various demo use-cases, in user-centered research, and in the lab work of a mandatory MMI course of an HCI master’s program. The derived insights highlight successful choices made as well as potential areas for improvement.}, address = {New York, NY, USA}, author = {Zimmerer, Chris and Fischbach, Martin and Latoschik, Marc Erich}, booktitle = {CHI Conference on Human Factors in Computing Systems Extended Abstracts}, keywords = {myown}, publisher = {Association for Computing Machinery}, series = {CHI EA '22}, title = {A Case Study on the Rapid Development of Natural and Synergistic Multimodal Interfaces for XR Use-Cases}, year = 2022 }
A Theory Based Adaptive Pedagogical Agent in a Reading App for Primary Students - A User Study Riedmann, Anna; Schaper, Philipp; Jakob, Benedikt; Lugrin, Birgit in Intelligent Tutoring Systems. ITS 2022. Lecture Notes in Computer Science, S. Crossley, E. Popescu (eds.) (2022). (Vol. 13284)
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@inproceedings{riedmann2022theory, author = {Riedmann, Anna and Schaper, Philipp and Jakob, Benedikt and Lugrin, Birgit}, booktitle = {Intelligent Tutoring Systems. ITS 2022. Lecture Notes in Computer Science}, editor = {Crossley, S. and Popescu, E.}, keywords = {schaper}, publisher = {Springer}, title = {A Theory Based Adaptive Pedagogical Agent in a Reading App for Primary Students - A User Study}, volume = 13284, year = 2022 }
Layered Drawing of Undirected Graphs with Generalized Port Constraints Zink, Johannes; Walter, Julian; Baumeister, Joachim; Wolff, Alexander in Computational Geometry: Theory and Applications (2022). 105--106(101886) 1–29.
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The aim of this research is a practical method to draw cable plans of complex machines. Such plans consist of electronic components and cables connecting specific ports of the components. Since the machines are configured for each client individually, cable plans need to be drawn automatically. The drawings must be well readable so that technicians can use them to debug the machines. In order to model plug sockets, we introduce port groups; within a group, ports can change their position (which we use to improve the aesthetics of the layout), but together the ports of a group must form a contiguous block. \par We approach the problem of drawing such cable plans by extending the well-known Sugiyama framework such that it incorporates ports and port groups. Since the framework assumes directed graphs, we propose several ways to orient the edges of the given undirected graph. We compare these methods experimentally, both on real-world data and synthetic data that carefully simulates real-world data. We measure the aesthetics of the resulting drawings by counting bends and crossings. Using these metrics, we experimentally compare our approach to Kieler [JVLC 2014], a library for drawing graphs in the presence of port constraints. Our method produced 10--30 \% fewer crossings, while it performed equally well or slightly worse than Kieler with respect to the number of bends and the time used to compute a drawing.

@article{zwbw-ldugg-CGTA22, abstract = {The aim of this research is a practical method to draw cable plans of complex machines. Such plans consist of electronic components and cables connecting specific ports of the components. Since the machines are configured for each client individually, cable plans need to be drawn automatically. The drawings must be well readable so that technicians can use them to debug the machines. In order to model plug sockets, we introduce port groups; within a group, ports can change their position (which we use to improve the aesthetics of the layout), but together the ports of a group must form a contiguous block. \par We approach the problem of drawing such cable plans by extending the well-known Sugiyama framework such that it incorporates ports and port groups. Since the framework assumes directed graphs, we propose several ways to orient the edges of the given undirected graph. We compare these methods experimentally, both on real-world data and synthetic data that carefully simulates real-world data. We measure the aesthetics of the resulting drawings by counting bends and crossings. Using these metrics, we experimentally compare our approach to Kieler [JVLC 2014], a library for drawing graphs in the presence of port constraints. Our method produced 10–30 \% fewer crossings, while it performed equally well or slightly worse than Kieler with respect to the number of bends and the time used to compute a drawing.}, author = {Zink, Johannes and Walter, Julian and Baumeister, Joachim and Wolff, Alexander}, journal = {Computational Geometry: Theory and Applications}, keywords = {port_constraints}, number = 101886, pages = {1–29}, title = {Layered Drawing of Undirected Graphs with Generalized Port Constraints}, volume = {105–106}, year = 2022 }
Simple Algorithms for Partial and Simultaneous Rectangular Duals with Given Contact Orientations Chaplick, Steven; Felsner, Stefan; Kindermann, Philipp; Klawitter, Jonathan; Rutter, Ignaz; Wolff, Alexander in Theoretical Computer Science (2022). 919 66–74.
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A rectangular dual of a graph $G$ is a contact representation of $G$ by axis-aligned rectangles such that (i) no four rectangles share a point and (ii) the union of all rectangles is a rectangle. The \emph{partial representation extension problem} for rectangular duals asks whether a given partial rectangular dual can be extended to a rectangular dual, that is, whether there exists a rectangular dual where some vertices are represented by prescribed rectangles. The \emph{simultaneous representation problem} for rectangular duals asks whether two (or more) given graphs that share a subgraph admit rectangular duals that coincide on the shared subgraph. Combinatorially, a rectangular dual can be described by a regular edge labeling (REL), which determines the orientations of the rectangle contacts. \par We describe linear-time algorithms for the partial representation extension problem and the simultaneous representation problem for rectangular duals when each input graph is given together with a REL. Both algorithms are based on formulations as linear programs, yet they have geometric interpretations and can be seen as extensions of the classic algorithm by Kant and He that computes a rectangular dual for a given graph.

@article{cfkkrw-sapsr-TCS22, abstract = {A rectangular dual of a graph $G$ is a contact representation of $G$ by axis-aligned rectangles such that (i) no four rectangles share a point and (ii) the union of all rectangles is a rectangle. The \emph{partial representation extension problem} for rectangular duals asks whether a given partial rectangular dual can be extended to a rectangular dual, that is, whether there exists a rectangular dual where some vertices are represented by prescribed rectangles. The \emph{simultaneous representation problem} for rectangular duals asks whether two (or more) given graphs that share a subgraph admit rectangular duals that coincide on the shared subgraph. Combinatorially, a rectangular dual can be described by a regular edge labeling (REL), which determines the orientations of the rectangle contacts. \par We describe linear-time algorithms for the partial representation extension problem and the simultaneous representation problem for rectangular duals when each input graph is given together with a REL. Both algorithms are based on formulations as linear programs, yet they have geometric interpretations and can be seen as extensions of the classic algorithm by Kant and He that computes a rectangular dual for a given graph.}, author = {Chaplick, Steven and Felsner, Stefan and Kindermann, Philipp and Klawitter, Jonathan and Rutter, Ignaz and Wolff, Alexander}, journal = {Theoretical Computer Science}, keywords = {simultaneous_representation}, pages = {66–74}, title = {Simple Algorithms for Partial and Simultaneous Rectangular Duals with Given Contact Orientations}, volume = 919, year = 2022 }
Bounding and Computing Obstacle Numbers of Graphs Balko, Martin; Chaplick, Steven; Gupta, Siddharth; Hoffmann, Michael; Valtr, Pavel; Wolff, Alexander in Proc. 30th Europ. Symp. Algorithms (ESA’22), LIPIcs, S. Chechik, G. Navarro, E. Rotenberg, G. Herman (eds.) (2022). (Vol. 244) 11:1–13.
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@inproceedings{bcghvw-bcong-ESA22, author = {Balko, Martin and Chaplick, Steven and Gupta, Siddharth and Hoffmann, Michael and Valtr, Pavel and Wolff, Alexander}, booktitle = {Proc. 30th Europ. Symp. Algorithms (ESA'22)}, editor = {Chechik, Shiri and Navarro, Gonzalo and Rotenberg, Eva and Herman, Grzegorz}, keywords = {myown}, pages = {11:1–13}, publisher = {Schloss Dagstuhl – Leibniz-Zentrum f{\"u}r Informatik}, series = {LIPIcs}, title = {Bounding and Computing Obstacle Numbers of Graphs}, volume = 244, year = 2022 }
Are You Referring to Me? - Giving Virtual Objects Awareness Stingl, René; Zimmerer, Chris; Fischbach, Martin; Latoschik, Marc Erich in 2022 IEEE International Symposium on Mixed and Augmented Reality Adjunct (ISMAR-Adjunct) (2022). 671–673.
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This work introduces an interaction technique to determine the user’s non-verbal deixis in Virtual Reality (VR) applications. We tailored it for multimodal speech & gesture interfaces (MMIs). Here, non-verbal deixis is often determined by the use of ray-casting due to its simplicity and intuitiveness. However, ray-casting’s rigidness and dichotomous nature pose limitations concerning the MMI’s flexibility and efficiency. In contrast, our technique considers a more comprehensive set of directional cues to determine non-verbal deixis and provides probabilistic output to tackle these limitations. We present a machine-learning-based reference implementation of our technique in VR and the results of a first performance benchmark. Future work includes an in-depth user study evaluating our technique’s user experience in an MMI.

@inproceedings{9974498, abstract = {This work introduces an interaction technique to determine the user’s non-verbal deixis in Virtual Reality (VR) applications. We tailored it for multimodal speech & gesture interfaces (MMIs). Here, non-verbal deixis is often determined by the use of ray-casting due to its simplicity and intuitiveness. However, ray-casting’s rigidness and dichotomous nature pose limitations concerning the MMI’s flexibility and efficiency. In contrast, our technique considers a more comprehensive set of directional cues to determine non-verbal deixis and provides probabilistic output to tackle these limitations. We present a machine-learning-based reference implementation of our technique in VR and the results of a first performance benchmark. Future work includes an in-depth user study evaluating our technique’s user experience in an MMI.}, author = {Stingl, René and Zimmerer, Chris and Fischbach, Martin and Latoschik, Marc Erich}, booktitle = {2022 IEEE International Symposium on Mixed and Augmented Reality Adjunct (ISMAR-Adjunct)}, keywords = {myown}, pages = {671-673}, title = {Are You Referring to Me? - Giving Virtual Objects Awareness}, year = 2022 }
The Segment Number: Algorithms and Universal Lower Bounds for Some Classes of Planar Graphs Goe{\ss}mann, Ina; Klawitter, Jonathan; Klemz, Boris; Klesen, Felix; Kobourov, Stephen G.; Kryven, Myroslav; Wolff, Alexander; Zink, Johannes in Proc. 48th Int. Workshop Graph-Theoretic Concepts Comput. Sci. (WG’22), Lecture Notes in Computer Science, M. Bekos, M. Kaufmann (eds.) (2022). (Vol. 13453) 16 pages.
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@inproceedings{gkkkkkwz-snaul-WG22, author = {Goe{\ss}mann, Ina and Klawitter, Jonathan and Klemz, Boris and Klesen, Felix and Kobourov, Stephen G. and Kryven, Myroslav and Wolff, Alexander and Zink, Johannes}, booktitle = {Proc. 48th Int. Workshop Graph-Theoretic Concepts Comput. Sci. (WG'22)}, editor = {Bekos, Michael and Kaufmann, Michael}, keywords = {visual_complexity}, pages = {16 pages}, publisher = {Springer-Verlag}, series = {Lecture Notes in Computer Science}, title = {The Segment Number: Algorithms and Universal Lower Bounds for Some Classes of Planar Graphs}, volume = 13453, year = 2022 }
Minimum Rectilinear Polygons for Given Angle Sequences Evans, William S.; Fleszar, Krzysztof; Kindermann, Philipp; Saeedi, Noushin; Shin, Chan-Su; Wolff, Alexander in Computational Geometry: Theory and Applications (2022). 100(101820) 1–39.
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A rectilinear polygon is a simple polygon whose edges are axis-aligned. Walking counterclockwise on the boundary of such a polygon yields a sequence of left turns and right turns. The number of left turns always equals the number of right turns plus four. It is known that any such sequence can be realized by a rectilinear polygon. \par In this paper, we consider the problem of finding realizations that minimize the perimeter or the area of the polygon or the area of the bounding box of the polygon. We show that all three problems are NP-hard in general. This answers an open question of Patrignani [CGTA 2001], who showed that it is NP-hard to minimize the area of the bounding box of an orthogonal drawing of a given planar graph. We also show that realizing a polyline within a bounding box of minimum area (or within a fixed given rectangle) is NP-hard. Then we consider the special cases of x-monotone and xy-monotone rectilinear polygons. For these, we can optimize the three objectives efficiently.

@article{efkssw-mrpga-CGTA22, abstract = {A rectilinear polygon is a simple polygon whose edges are axis-aligned. Walking counterclockwise on the boundary of such a polygon yields a sequence of left turns and right turns. The number of left turns always equals the number of right turns plus four. It is known that any such sequence can be realized by a rectilinear polygon. \par In this paper, we consider the problem of finding realizations that minimize the perimeter or the area of the polygon or the area of the bounding box of the polygon. We show that all three problems are NP-hard in general. This answers an open question of Patrignani [CGTA 2001], who showed that it is NP-hard to minimize the area of the bounding box of an orthogonal drawing of a given planar graph. We also show that realizing a polyline within a bounding box of minimum area (or within a fixed given rectangle) is NP-hard. Then we consider the special cases of x-monotone and xy-monotone rectilinear polygons. For these, we can optimize the three objectives efficiently.}, author = {Evans, William S. and Fleszar, Krzysztof and Kindermann, Philipp and Saeedi, Noushin and Shin, Chan-Su and Wolff, Alexander}, journal = {Computational Geometry: Theory and Applications}, keywords = {myown}, number = 101820, pages = {1–39}, title = {Minimum Rectilinear Polygons for Given Angle Sequences}, volume = 100, year = 2022 }
The Relationship Between the Distribution of Training Intensity and Performance of Kayak and Canoe Sprinters: A Retrospective Observational Analysis of One Season of Competition Matzka, Manuel; Leppich, Robert; Holmberg, Hans-Christer; Sperlich, Billy; Zinner, Christoph in Frontiers in Sports and Active Living (2022). 3 788108.
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@article{matzka2022relationship, author = {Matzka, Manuel and Leppich, Robert and Holmberg, Hans-Christer and Sperlich, Billy and Zinner, Christoph}, journal = {Frontiers in Sports and Active Living}, keywords = {myown}, pages = 788108, publisher = {Frontiers Media SA}, title = {The Relationship Between the Distribution of Training Intensity and Performance of Kayak and Canoe Sprinters: A Retrospective Observational Analysis of One Season of Competition}, volume = 3, year = 2022 }
The Computational Complexity of the {ChordLink} Model Kindermann, Philipp; Sauer, Jan; Wolff, Alexander in Proc. 38th Europ. Workshop Comput. Geom. (EuroCG’22), E. {Di Giacomo}, F. Montecchiani (eds.) (2022). 10:1–7.
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@inproceedings{ksw-cccm-EuroCG22, author = {Kindermann, Philipp and Sauer, Jan and Wolff, Alexander}, booktitle = {Proc. 38th Europ. Workshop Comput. Geom. (EuroCG'22)}, editor = {{Di Giacomo}, Emilio and Montecchiani, Fabrizio}, keywords = {myown}, pages = {10:1–7}, title = {The Computational Complexity of the {ChordLink} Model}, year = 2022 }
DeepCrypt - Deep Learning for QoE Monitoring and Fingerprinting of User Actions in Adaptive Video Streaming Casas, Pedro; Seufert, Michael; Wassermann, Sarah; Gardlo, Bruno; Wehner, Nikolas; Schatz, Raimund in IEEE Conference on Network Softwarization (IEEE NetSoft 2022) (2022).
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We introduce DeepCrypt, a deep-learning based approach to analyze YouTube video streaming Quality of Experience (QoE) from the Internet Service Provider (ISP) perspective, relying exclusively on the analysis of encrypted network traffic. Using raw features derived on-line from the encrypted stream of bytes, DeepCrypt can infer six different video QoE indicators capturing the user-perceived performance of the service, including the initial playback delay, the number and frequency of rebuffering events, the video playback quality, the video encoding bitrate, and the number of quality changes. DeepCrypt offers deep visibility into the behavior of the end-user, enabling the fingerprinting and detection of different user actions on the video player, such as video pauses and playback scrubbing (forward, backward, out-of-buffer), offering a complete visibility on the video streaming process from in-network traffic measurements. Extensive evaluations over a large and heterogeneous dataset composed of mobile and fixed-line measurements, using the YouTube HTML5 player, the native YouTube mobile app, as well as a generic HTML5 video player built on top of open source libraries, and considering measurements collected at different ISPs, confirm the out-performance of DeepCrypt over previously used shallow-learning models, as well as the deep-model generalization to different video players and network setups. To the best of our knowledge, this is the first paper tackling such a combined QoE and user-actions approach for video streaming applications, using deep learning models over heterogeneous measurements.

@inproceedings{info3-inproceedings-2022-9, abstract = {We introduce DeepCrypt, a deep-learning based approach to analyze YouTube video streaming Quality of Experience (QoE) from the Internet Service Provider (ISP) perspective, relying exclusively on the analysis of encrypted network traffic. Using raw features derived on-line from the encrypted stream of bytes, DeepCrypt can infer six different video QoE indicators capturing the user-perceived performance of the service, including the initial playback delay, the number and frequency of rebuffering events, the video playback quality, the video encoding bitrate, and the number of quality changes. DeepCrypt offers deep visibility into the behavior of the end-user, enabling the fingerprinting and detection of different user actions on the video player, such as video pauses and playback scrubbing (forward, backward, out-of-buffer), offering a complete visibility on the video streaming process from in-network traffic measurements. Extensive evaluations over a large and heterogeneous dataset composed of mobile and fixed-line measurements, using the YouTube HTML5 player, the native YouTube mobile app, as well as a generic HTML5 video player built on top of open source libraries, and considering measurements collected at different ISPs, confirm the out-performance of DeepCrypt over previously used shallow-learning models, as well as the deep-model generalization to different video players and network setups. To the best of our knowledge, this is the first paper tackling such a combined QoE and user-actions approach for video streaming applications, using deep learning models over heterogeneous measurements.}, author = {Casas, Pedro and Seufert, Michael and Wassermann, Sarah and Gardlo, Bruno and Wehner, Nikolas and Schatz, Raimund}, booktitle = {IEEE Conference on Network Softwarization (IEEE NetSoft 2022)}, keywords = {myown}, month = 6, title = {DeepCrypt - Deep Learning for QoE Monitoring and Fingerprinting of User Actions in Adaptive Video Streaming}, year = 2022 }
A literature review on optimization techniques for adaptation planning in adaptive systems: State of the art and research directions Henrichs, Elia; Lesch, Veronika; Straesser, Martin; Kounev, Samuel; Krupitzer, Christian in Information and Software Technology (2022). 149 106940.
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Context: Recent developments in modern IT systems including internet of things, edge/fog computing, or cyber–physical systems support intelligent and seamless interaction between users and systems. This requires a reaction to changes in their environment or the system. Adaptive systems provide mechanisms for these reactions. Objective: To implement this functionality, several approaches for the planning of adaptations exist that rely on rules, utility functions, or advanced techniques, such as machine learning. As the adaptation space with possible options is often extensively huge, optimization techniques might support efficient determination of the adaptation space and identify the system’s optimal configuration. With this paper, we provide a systematic review of adaptation planning as the optimization target. Method: In this paper, we review which optimization techniques are applied for adaptation planning in adaptive systems using a systematic literature review approach. Results: We reviewed 115 paper in detail out of an initial search set of 9,588 papers. Our analysis reveals that learning techniques and genetic algorithms are by far dominant; in total, heuristics (anytime learning) are more frequently applied as exact algorithms. We observed that around 57% of the approaches target multi-objectiveness and around 30% integrate distributed optimization. As last dimension, we focused on situation-awareness, which is only supported by two approaches. Conclusion: In this paper, we provide an overview of the current state of the art of approaches that rely on optimization techniques for planning adaptations in adaptive systems and further derive open research challenges, in particular regarding the integration of distributed optimization and situation-awareness.

@article{HENRICHS2022106940, abstract = {Context: Recent developments in modern IT systems including internet of things, edge/fog computing, or cyber–physical systems support intelligent and seamless interaction between users and systems. This requires a reaction to changes in their environment or the system. Adaptive systems provide mechanisms for these reactions. Objective: To implement this functionality, several approaches for the planning of adaptations exist that rely on rules, utility functions, or advanced techniques, such as machine learning. As the adaptation space with possible options is often extensively huge, optimization techniques might support efficient determination of the adaptation space and identify the system’s optimal configuration. With this paper, we provide a systematic review of adaptation planning as the optimization target. Method: In this paper, we review which optimization techniques are applied for adaptation planning in adaptive systems using a systematic literature review approach. Results: We reviewed 115 paper in detail out of an initial search set of 9,588 papers. Our analysis reveals that learning techniques and genetic algorithms are by far dominant; in total, heuristics (anytime learning) are more frequently applied as exact algorithms. We observed that around 57% of the approaches target multi-objectiveness and around 30% integrate distributed optimization. As last dimension, we focused on situation-awareness, which is only supported by two approaches. Conclusion: In this paper, we provide an overview of the current state of the art of approaches that rely on optimization techniques for planning adaptations in adaptive systems and further derive open research challenges, in particular regarding the integration of distributed optimization and situation-awareness.}, author = {Henrichs, Elia and Lesch, Veronika and Straesser, Martin and Kounev, Samuel and Krupitzer, Christian}, journal = {Information and Software Technology}, keywords = {myown}, pages = 106940, title = {A literature review on optimization techniques for adaptation planning in adaptive systems: State of the art and research directions}, volume = 149, year = 2022 }
CortexVR: Immersive analysis and training of cognitive executive functions of soccer players using virtual reality and machine learning Krupitzer, Christian; Naber, Jens; Stauffert, Jan-Philipp; Mayer, Jan; Spielmann, Jan; Ehmann, Paul; Boci, Noel; Bürkle, Maurice; Ho, André; Komorek, Clemens; others in Frontiers in Psychology (2022). 13:754732
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Goal: This paper presents an immersive Virtual Reality (VR) system to analyze and train Executive Functions (EFs) of soccer players. EFs are important cognitive functions for athletes. They are a relevant quality that distinguishes amateurs from professionals. Method: The system is based on immersive technology, hence, the user interacts naturally and experiences a training session in a virtual world. The proposed system has a modular design supporting the extension of various so-called game modes. Game modes combine selected game mechanics with specific simulation content to target particular training aspects. The system architecture decouples selection/parameterization and analysis of training sessions via a coaching app from an Unity3D-based VR simulation core. Monitoring of user performance and progress is recorded by a database that sends the necessary feedback to the coaching app for analysis. Results: The system is tested for VR-critical performance criteria to reveal the usefulness of a new interaction paradigm in the cognitive training and analysis of EFs. Subjective ratings for overall usability show that the design as VR application enhances the user experience compared to a traditional desktop app; whereas the new, unfamiliar interaction paradigm does not negatively impact the effort for using the application. Conclusion: The system can provide immersive training of EF in a fully virtual environment, eliminating potential distraction. It further provides an easy-to-use analyzes tool to compare user but also an automatic, adaptive training mode.

@article{krupitzer2022cortexvr, abstract = {Goal: This paper presents an immersive Virtual Reality (VR) system to analyze and train Executive Functions (EFs) of soccer players. EFs are important cognitive functions for athletes. They are a relevant quality that distinguishes amateurs from professionals. Method: The system is based on immersive technology, hence, the user interacts naturally and experiences a training session in a virtual world. The proposed system has a modular design supporting the extension of various so-called game modes. Game modes combine selected game mechanics with specific simulation content to target particular training aspects. The system architecture decouples selection/parameterization and analysis of training sessions via a coaching app from an Unity3D-based VR simulation core. Monitoring of user performance and progress is recorded by a database that sends the necessary feedback to the coaching app for analysis. Results: The system is tested for VR-critical performance criteria to reveal the usefulness of a new interaction paradigm in the cognitive training and analysis of EFs. Subjective ratings for overall usability show that the design as VR application enhances the user experience compared to a traditional desktop app; whereas the new, unfamiliar interaction paradigm does not negatively impact the effort for using the application. Conclusion: The system can provide immersive training of EF in a fully virtual environment, eliminating potential distraction. It further provides an easy-to-use analyzes tool to compare user but also an automatic, adaptive training mode.}, author = {Krupitzer, Christian and Naber, Jens and Stauffert, Jan-Philipp and Mayer, Jan and Spielmann, Jan and Ehmann, Paul and Boci, Noel and Bürkle, Maurice and Ho, André and Komorek, Clemens and others}, journal = {Frontiers in Psychology}, keywords = {own}, publisher = {Frontiers}, title = {CortexVR: Immersive analysis and training of cognitive executive functions of soccer players using virtual reality and machine learning}, volume = {13:754732}, year = 2022 }
Don’t Touch This! - Investigating the Potential of Visualizing Touched Surfaces on the Consideration of Behavior Change Ganal, E.; Heimbrock, M.; Schaper, P.; Lugrin, B. in Persuasive Technology 2022, N. Baghaei, J. Vassileva, R. Ali, K. Oyibo (eds.) (2022).
- [ BibTeX ]
@inproceedings{ganal2022touch, author = {Ganal, E. and Heimbrock, M. and Schaper, P. and Lugrin, B.}, booktitle = {Persuasive Technology 2022}, editor = {Baghaei, N. and Vassileva, J. and Ali, R. and Oyibo, K.}, keywords = {schaper}, publisher = {Springer International Publishing}, title = {Don’t Touch This! - Investigating the Potential of Visualizing Touched Surfaces on the Consideration of Behavior Change}, year = 2022 }
The Effects of Avatar and Environment Design on Embodiment, Presence, Activation, and Task Load in a Virtual Reality Exercise Application Bartl, Andrea; Merz, Christian; Roth, Daniel; Latoschik, Marc Erich in IEEE International Symposium on Mixed and Augmented Reality (ISMAR) (2022).
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ABSTRACT The development of embodied Virtual Reality (VR) systems involves multiple central design choices. These design choices affect the user perception and therefore require thorough consideration. This article reports on two user studies investigating the influence of common design choices on relevant intermediate factors (sense of embodiment, presence, motivation, activation, and task load) in a VR application for physical exercises. The first study manipulated the avatar fidelity (abstract, partial body vs. anthropomorphic, full-body) and the environment (with vs. without mirror). The second study manipulated the avatar type (healthy vs. injured) and the environment type (beach vs. hospital) and, hence, the avatar-environment congruence. The full-body avatar significantly increased the sense of embodiment and decreased mental demand. Interestingly, the mirror did not influence the dependent variables. The injured avatar significantly increased the temporal demand. The beach environment significantly reduced the tense activation. On the beach, participants felt more present in the incongruent condition embodying the injured avatar.

@inproceedings{bartl2022effects, abstract = {ABSTRACT The development of embodied Virtual Reality (VR) systems involves multiple central design choices. These design choices affect the user perception and therefore require thorough consideration. This article reports on two user studies investigating the influence of common design choices on relevant intermediate factors (sense of embodiment, presence, motivation, activation, and task load) in a VR application for physical exercises. The first study manipulated the avatar fidelity (abstract, partial body vs. anthropomorphic, full-body) and the environment (with vs. without mirror). The second study manipulated the avatar type (healthy vs. injured) and the environment type (beach vs. hospital) and, hence, the avatar-environment congruence. The full-body avatar significantly increased the sense of embodiment and decreased mental demand. Interestingly, the mirror did not influence the dependent variables. The injured avatar significantly increased the temporal demand. The beach environment significantly reduced the tense activation. On the beach, participants felt more present in the incongruent condition embodying the injured avatar.}, author = {Bartl, Andrea and Merz, Christian and Roth, Daniel and Latoschik, Marc Erich}, booktitle = {IEEE International Symposium on Mixed and Augmented Reality (ISMAR)}, keywords = {myown}, title = {The Effects of Avatar and Environment Design on Embodiment, Presence, Activation, and Task Load in a Virtual Reality Exercise Application}, year = 2022 }
Conflict Handling in Product Configuration using Answer Set Programming Herud, Konstantin; Baumeister, Joachim; Sabuncu, Orkunt; Schaub, Torsten in ICLP Workshop Answer Set Programming and Other Computing Paradigms (2022).
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- [ URL ]
@inproceedings{hbs:22, author = {Herud, Konstantin and Baumeister, Joachim and Sabuncu, Orkunt and Schaub, Torsten}, booktitle = {ICLP Workshop Answer Set Programming and Other Computing Paradigms}, keywords = {myown}, title = {Conflict Handling in Product Configuration using Answer Set Programming}, year = 2022 }
A Survey on Secure Group Communication Schemes with Focus on IoT Communication Prantl, Thomas; Zeck, Timo; Bauer, André; Ten, Peter; Prantl, Dominik; Ben Yahya, Ala Eddine; Iffländer, Lukas; Dmitrienko, Alexandra; Krupitzer, Christian; Kounev, Samuel in IEEE Access (2022).
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@article{PrZeBaTePrYaIfDmKrKo_IEEEAccess_SGCSurvey, author = {Prantl, Thomas and Zeck, Timo and Bauer, André and Ten, Peter and Prantl, Dominik and Ben Yahya, Ala Eddine and Iffländer, Lukas and Dmitrienko, Alexandra and Krupitzer, Christian and Kounev, Samuel}, journal = {IEEE Access}, keywords = {t_journalmagazine}, publisher = {IEEE}, title = {A Survey on Secure Group Communication Schemes with Focus on IoT Communication}, year = 2022 }
A Survey on Secure Group Communication Schemes with Focus on IoT Communication Prantl, Thomas; Zeck, Timo; Bauer, André; Ten, Peter; Prantl, Dominik; Ben Yahya, Ala Eddine; Iffländer, Lukas; Dmitrienko, Alexandra; Krupitzer, Christian; Kounev, Samuel in IEEE Access (2022).
- [ BibTeX ]
@article{PrZeBaTePrYaIfDmKrKo_IEEEAccess_SGCSurvey, author = {Prantl, Thomas and Zeck, Timo and Bauer, André and Ten, Peter and Prantl, Dominik and Ben Yahya, Ala Eddine and Iffländer, Lukas and Dmitrienko, Alexandra and Krupitzer, Christian and Kounev, Samuel}, journal = {IEEE Access}, keywords = {t_journalmagazine}, publisher = {IEEE}, title = {A Survey on Secure Group Communication Schemes with Focus on IoT Communication}, year = 2022 }
Edge-Case Integration into Established NAT Traversal Techniques Keller, Simon; Hoßfeld, Tobias; von Mammen, Sebastian in 2022 IEEE Ninth International Conference on Communications and Electronics (ICCE) (2022). 75–80.
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- [ URL ]
Traversing Network Address Translation (NAT) is often necessary for establishing direct communication between clients. The traversal of NAT with static port translation is solved in many cases by the Session Traversal Utilities for NAT (STUN) protocol. Nevertheless, it does not cover the traversal of progressing symmetric and random symmetric NAT, which make it necessary to correctly predict opened ports. This paper presents a method for predicting (a) progressing symmetric NAT-translated ports based on a network traffic model and the Expected Value Method, and (b) random symmetric NAT-translated ports based on heuristics between monitored and opened ports across numerous traversal attempts. Tests were conducted in German cities using local cellular communication providers. Compared to established approaches, they yielded considerable improvements traversing progressing symmetric NAT and slight improvements traversing random symmetric NAT in real-world environments.

@inproceedings{9852092, abstract = {Traversing Network Address Translation (NAT) is often necessary for establishing direct communication between clients. The traversal of NAT with static port translation is solved in many cases by the Session Traversal Utilities for NAT (STUN) protocol. Nevertheless, it does not cover the traversal of progressing symmetric and random symmetric NAT, which make it necessary to correctly predict opened ports. This paper presents a method for predicting (a) progressing symmetric NAT-translated ports based on a network traffic model and the Expected Value Method, and (b) random symmetric NAT-translated ports based on heuristics between monitored and opened ports across numerous traversal attempts. Tests were conducted in German cities using local cellular communication providers. Compared to established approaches, they yielded considerable improvements traversing progressing symmetric NAT and slight improvements traversing random symmetric NAT in real-world environments.}, author = {Keller, Simon and Hoßfeld, Tobias and von Mammen, Sebastian}, booktitle = {2022 IEEE Ninth International Conference on Communications and Electronics (ICCE)}, keywords = {myown}, month = {July}, pages = {75-80}, title = {Edge-Case Integration into Established NAT Traversal Techniques}, year = 2022 }
On Learning Hierarchical Embeddings from Encrypted Network Traffic Wehner, Nikolas; Ring, Markus; Schüler, Joshua; Hotho, Andreas; Hoßfeld, Tobias; Seufert, Michael in 33th IEEE/IFIP Network Operations and Management Symposium (NOMS) (2022).
- [ Abstract ]
- [ BibTeX ]
This work presents a novel concept for learning embeddings from encrypted network traffic. In contrast to existing approaches, we evaluate the feasibility of hierarchical embeddings by iteratively aggregating packet embeddings to flow embeddings, and flow embeddings to trace embeddings. The hierarchical embedding concept was designed to especially consider complex dependencies of Internet traffic on different time scales. We describe this novel embedding concept for the domain of network traffic in full detail, and evaluate its performance for the downstream task of website fingerprinting, i.e., identifying websites from encrypted traffic, which is relevant for network management, e.g., as a prerequisite for QoE monitoring or for intrusion detection. Our evaluation reveals that embeddings are a promising solution for website fingerprinting as our model correctly labels up to 99.8\% of traces from 500 target websites.

@inproceedings{info3-inproceedings-2022-1, abstract = {This work presents a novel concept for learning embeddings from encrypted network traffic. In contrast to existing approaches, we evaluate the feasibility of hierarchical embeddings by iteratively aggregating packet embeddings to flow embeddings, and flow embeddings to trace embeddings. The hierarchical embedding concept was designed to especially consider complex dependencies of Internet traffic on different time scales. We describe this novel embedding concept for the domain of network traffic in full detail, and evaluate its performance for the downstream task of website fingerprinting, i.e., identifying websites from encrypted traffic, which is relevant for network management, e.g., as a prerequisite for QoE monitoring or for intrusion detection. Our evaluation reveals that embeddings are a promising solution for website fingerprinting as our model correctly labels up to 99.8\% of traces from 500 target websites.}, address = {Budapest, Hungary}, author = {Wehner, Nikolas and Ring, Markus and Schüler, Joshua and Hotho, Andreas and Hoßfeld, Tobias and Seufert, Michael}, booktitle = {33th IEEE/IFIP Network Operations and Management Symposium (NOMS)}, keywords = {myown}, month = 4, title = {On Learning Hierarchical Embeddings from Encrypted Network Traffic}, year = 2022 }
Joyful Adventures and Frightening Places - Designing Emotion-Inducing Virtual Environments Steinhaeusser, Sophia C; Oberdörfer, Sebastian; von Mammen, Sebastian; Latoschik, Marc Erich; Lugrin, Birgit in Frontiers in Virtual Reality (2022).
- [ BibTeX ]
- [ URL ]
@article{steinhaeusser2022joyful, author = {Steinhaeusser, Sophia C and Oberdörfer, Sebastian and von Mammen, Sebastian and Latoschik, Marc Erich and Lugrin, Birgit}, journal = {Frontiers in Virtual Reality}, keywords = {oberdoerfer}, title = {Joyful Adventures and Frightening Places - Designing Emotion-Inducing Virtual Environments}, year = 2022 }
Iteratively Digitizing an Analogue Syllable-Based Reading Intervention Riedmann, Anna; Schaper, Philipp; Donnermann, Melissa; Lein, Martina; Steinhaeusser, Sophia C.; Karageorgos, Panagiotis; Müller, Bettina; Richter, Tobias; Lugrin, Birgit in Interacting with Computers (2022).
- [ BibTeX ]
@article{2022, author = {Riedmann, Anna and Schaper, Philipp and Donnermann, Melissa and Lein, Martina and Steinhaeusser, Sophia C. and Karageorgos, Panagiotis and Müller, Bettina and Richter, Tobias and Lugrin, Birgit}, journal = {Interacting with Computers}, keywords = {steinhaeusser}, publisher = {Oxford University Press}, title = {Iteratively Digitizing an Analogue Syllable-Based Reading Intervention}, year = 2022 }
Automated Triage of Performance Change Points Using Time Series Analysis and Machine Learning Bauer, André; Straesser, Martin; Beierlieb, Lukas; Meissner, Maximilian; Kounev, Samuel in Proceedings of the 2022 ACM/SPEC on International Conference on Performance Engineering (2022).
- [ BibTeX ]
@conference{bauer2022automated, author = {Bauer, André and Straesser, Martin and Beierlieb, Lukas and Meissner, Maximilian and Kounev, Samuel}, booktitle = {Proceedings of the 2022 ACM/SPEC on International Conference on Performance Engineering}, keywords = {timeseries}, month = 4, publisher = {ACM}, title = {Automated Triage of Performance Change Points Using Time Series Analysis and Machine Learning}, year = 2022 }
SPEC Efficiency Benchmark Development: How to Contribute to the Future of Energy Conservation Meissner, Maximilian; Lange, Klaus-Dieter; Arnold, Jeremy; Sharma, Sanjay; Tipley, Roger; Rawtani, Nishant; Reiner, David; Petrich, Mike; Cragin, Aaron in Companion of the 2022 ACM/SPEC International Conference on Performance Engineering (2022).
- [ Abstract ]
- [ BibTeX ]
A driving force behind the improvement of server efficiency in recent years is the use of SPEC benchmarks. They are used in mandatory government regulations, the ISO/IEC 21836:2020 standard, and product marketing, giving server manufacturers and buyers significant incentive to improve energy efficiency. To produce relevant results, benchmarks need to take into account future trends in hardware and software development, such as the introduction of new accelerators and workloads. To keep pace with the development of the fast moving IT landscape, SPEC plans to introduce a workload bounty program to encourage researchers to develop novel workloads. Submitted workloads will be considered for inclusion in future SPEC Efficiency benchmarks and rewarded. In this paper, we outline the process of energy-efficiency benchmark development. SPEC ensures the development of high-quality benchmarks for government regulations through its extensive experience and collaboration with stakeholders from industry, academia, and governments. One of the tools that emerged from this process is the Chauffeur Worklet Development Kit (WDK), which can be used by researchers to develop next-generation workloads to enhance the real-world relevance of future SPEC benchmarks, a critical element for the benchmarks to contribute to future energy conservation.

@inproceedings{meissner2022efficiency, abstract = {A driving force behind the improvement of server efficiency in recent years is the use of SPEC benchmarks. They are used in mandatory government regulations, the ISO/IEC 21836:2020 standard, and product marketing, giving server manufacturers and buyers significant incentive to improve energy efficiency. To produce relevant results, benchmarks need to take into account future trends in hardware and software development, such as the introduction of new accelerators and workloads. To keep pace with the development of the fast moving IT landscape, SPEC plans to introduce a workload bounty program to encourage researchers to develop novel workloads. Submitted workloads will be considered for inclusion in future SPEC Efficiency benchmarks and rewarded. In this paper, we outline the process of energy-efficiency benchmark development. SPEC ensures the development of high-quality benchmarks for government regulations through its extensive experience and collaboration with stakeholders from industry, academia, and governments. One of the tools that emerged from this process is the Chauffeur Worklet Development Kit (WDK), which can be used by researchers to develop next-generation workloads to enhance the real-world relevance of future SPEC benchmarks, a critical element for the benchmarks to contribute to future energy conservation.}, address = {New York, NY, USA}, author = {Meissner, Maximilian and Lange, Klaus-Dieter and Arnold, Jeremy and Sharma, Sanjay and Tipley, Roger and Rawtani, Nishant and Reiner, David and Petrich, Mike and Cragin, Aaron}, booktitle = {Companion of the 2022 ACM/SPEC International Conference on Performance Engineering}, keywords = {myown}, month = {April}, publisher = {ACM}, title = {SPEC Efficiency Benchmark Development: How to Contribute to the Future of Energy Conservation}, year = 2022 }
An Experience Report on the Suitability of a Distributed Group Encryption Scheme for an IoT Use Case Prantl, Thomas; Engel, Simon; Bauer, Andre; Ben Yahya, Ala Eddine; Herrnleben, Stefan; Iffländer, Lukas; Dmitrienko, Alexandra; Kounev, Samuel in 2022 IEEE 95th Vehicular Technology Conference (VTC2022) (2022).
- [ BibTeX ]
@inproceedings{PrEnBaAlHeIfDmKo2022-IoT/CPS-DistributedGroupEncryption, author = {Prantl, Thomas and Engel, Simon and Bauer, Andre and Ben Yahya, Ala Eddine and Herrnleben, Stefan and Iffländer, Lukas and Dmitrienko, Alexandra and Kounev, Samuel}, booktitle = {2022 IEEE 95th Vehicular Technology Conference (VTC2022)}, keywords = {myown}, organization = {IEEE}, title = {An Experience Report on the Suitability of a Distributed Group Encryption Scheme for an IoT Use Case}, year = 2022 }
An Experience Report on the Suitability of a Distributed Group Encryption Scheme for an IoT Use Case Prantl, Thomas; Engel, Simon; Bauer, Andre; Ben Yahya, Ala Eddine; Herrnleben, Stefan; Iffländer, Lukas; Dmitrienko, Alexandra; Kounev, Samuel in 2022 IEEE 95th Vehicular Technology Conference (VTC2022) (2022).
- [ BibTeX ]
@inproceedings{PrEnBaAlHeIfDmKo2022-IoT/CPS-DistributedGroupEncryption, author = {Prantl, Thomas and Engel, Simon and Bauer, Andre and Ben Yahya, Ala Eddine and Herrnleben, Stefan and Iffländer, Lukas and Dmitrienko, Alexandra and Kounev, Samuel}, booktitle = {2022 IEEE 95th Vehicular Technology Conference (VTC2022)}, keywords = {myown}, organization = {IEEE}, title = {An Experience Report on the Suitability of a Distributed Group Encryption Scheme for an IoT Use Case}, year = 2022 }
Anonymized GTP Tunnel Trace in Mobile IoT Raffeck, Simon; Geißler, Stefan; Krolikowski, Michael; Gebert, Steffen; Hoßfeld, Tobias (2022, February).
- [ Abstract ]
- [ BibTeX ]
Extensive dataset containing one whole month of create and delete events as well as the total, received, and transmitted volume of devices. We obtained data tunnel related events and volume values over 30 days in October 2021. In total the dataset contains a sample of 500000 unique devices that generate 155 million individual data tunnels.

@misc{info3-misc-2022-1, abstract = {Extensive dataset containing one whole month of create and delete events as well as the total, received, and transmitted volume of devices. We obtained data tunnel related events and volume values over 30 days in October 2021. In total the dataset contains a sample of 500000 unique devices that generate 155 million individual data tunnels.}, author = {Raffeck, Simon and Geißler, Stefan and Krolikowski, Michael and Gebert, Steffen and Hoßfeld, Tobias}, howpublished = {https://zenodo.org/record/6045708}, keywords = {can}, month = 2, title = {Anonymized GTP Tunnel Trace in Mobile IoT}, year = 2022 }
Performance Evaluation of Next-Generation Data Plane Architectures and their Components Geißler, Stefan PhD thesis, University of Würzburg. (2022, April).
- [ Abstract ]
- [ BibTeX ]
In this doctoral thesis we cover the performance evaluation of next generation data plane architectures, comprised of complex software as well as programmable hardware components that allow fine granular configuration. In the scope of the thesis we propose mechanisms to monitor the performance of singular components and model key performance indicators of software based packet processing solutions. We present novel approaches towards network abstraction that allow the integration of heterogeneous data plane technologies into a singular network while maintaining total transparency between control and data plane. Finally, we investigate a full, complex system consisting of multiple software-based solutions and perform a detailed performance analysis. We employ simulative approaches to investigate overload control mechanisms that allow efficient operation under adversary conditions. The contributions of this work build the foundation for future research in the areas of network softwarization and network function virtualization.

@phdthesis{info3-dissertation-2022-1, abstract = {In this doctoral thesis we cover the performance evaluation of next generation data plane architectures, comprised of complex software as well as programmable hardware components that allow fine granular configuration. In the scope of the thesis we propose mechanisms to monitor the performance of singular components and model key performance indicators of software based packet processing solutions. We present novel approaches towards network abstraction that allow the integration of heterogeneous data plane technologies into a singular network while maintaining total transparency between control and data plane. Finally, we investigate a full, complex system consisting of multiple software-based solutions and perform a detailed performance analysis. We employ simulative approaches to investigate overload control mechanisms that allow efficient operation under adversary conditions. The contributions of this work build the foundation for future research in the areas of network softwarization and network function virtualization.}, author = {Geißler, Stefan}, keywords = {ngn}, month = 4, school = {University of Würzburg}, title = {Performance Evaluation of Next-Generation Data Plane Architectures and their Components}, year = 2022 }
Layered drawing of undirected graphs with generalized port constraints Zink, Johannes; Walter, Julian; Baumeister, Joachim; Wolff, Alexander in Computational Geometry: Theory and Applications (2022). 105-106 101886.
- [ Abstract ]
- [ BibTeX ]
The aim of this research is a practical method to draw cable plans of complex machines. Such plans consist of electronic components and cables connecting specific ports of the components. Since the machines are configured for each client individually, cable plans need to be drawn automatically. The drawings must be well readable so that technicians can use them to debug the machines. In order to model plug sockets, we introduce port groups; within a group, ports can change their position (which we use to improve the aesthetics of the layout), but together the ports of a group must form a contiguous block. We approach the problem of drawing such cable plans by extending the well-known Sugiyama framework such that it incorporates ports and port groups. Since the framework assumes directed graphs, we propose several ways to orient the edges of the given undirected graph. We compare these methods experimentally, both on real-world data and synthetic data that carefully simulates real-world data. We measure the aesthetics of the resulting drawings by counting bends and crossings. Using these metrics, we experimentally compare our approach to Kieler JVLC 2014, a library for drawing graphs in the presence of port constraints. Our method produced 10--30 \% fewer crossings, while it performed equally well or slightly worse than Kieler with respect to the number of bends and the time used to compute a drawing.

@article{ZINK2022101886, abstract = {The aim of this research is a practical method to draw cable plans of complex machines. Such plans consist of electronic components and cables connecting specific ports of the components. Since the machines are configured for each client individually, cable plans need to be drawn automatically. The drawings must be well readable so that technicians can use them to debug the machines. In order to model plug sockets, we introduce port groups; within a group, ports can change their position (which we use to improve the aesthetics of the layout), but together the ports of a group must form a contiguous block. We approach the problem of drawing such cable plans by extending the well-known Sugiyama framework such that it incorporates ports and port groups. Since the framework assumes directed graphs, we propose several ways to orient the edges of the given undirected graph. We compare these methods experimentally, both on real-world data and synthetic data that carefully simulates real-world data. We measure the aesthetics of the resulting drawings by counting bends and crossings. Using these metrics, we experimentally compare our approach to Kieler JVLC 2014, a library for drawing graphs in the presence of port constraints. Our method produced 10–30 \% fewer crossings, while it performed equally well or slightly worse than Kieler with respect to the number of bends and the time used to compute a drawing.}, author = {Zink, Johannes and Walter, Julian and Baumeister, Joachim and Wolff, Alexander}, journal = {Computational Geometry: Theory and Applications}, keywords = {rokt}, pages = 101886, title = {Layered drawing of undirected graphs with generalized port constraints}, volume = {105-106}, year = 2022 }
Analytical Model for the Energy Efficiency in Low Power IoT Deployments Hoßfeld, Tobias; Raffeck, Simon; Loh, Frank; Geißler, Stefan in 1st International Workshop on Network Energy Efficiency in the Softwarization Era (2022).
- [ Abstract ]
- [ BibTeX ]
The recent rise of the Internet of Things (IoT) has given way to numerous challenges and research questions. One of the most critical issues in the area of low powered devices is the question of energy efficiency. Here, technologies like LoRa or Zigbee emerged, promising low power consumption while maintaining adequate performance. However, even when using these tailor made technologies, several configuration aspects need to be taken into account to provide high performance, energy efficient operation. To this end, we propose a generic model to compute the energy efficiency of wireless sensors under the assumption of perfect CSMA/CA channel access. We present numerical results for a typical LoRa device and highlight extensions towards other channel access mechanisms. Finally, we apply Kleinrock's power metric to obtain ideal system configurations for varying load parameters.

@inproceedings{info3-inproceedings-2022-6, abstract = {The recent rise of the Internet of Things (IoT) has given way to numerous challenges and research questions. One of the most critical issues in the area of low powered devices is the question of energy efficiency. Here, technologies like LoRa or Zigbee emerged, promising low power consumption while maintaining adequate performance. However, even when using these tailor made technologies, several configuration aspects need to be taken into account to provide high performance, energy efficient operation. To this end, we propose a generic model to compute the energy efficiency of wireless sensors under the assumption of perfect CSMA/CA channel access. We present numerical results for a typical LoRa device and highlight extensions towards other channel access mechanisms. Finally, we apply Kleinrock's power metric to obtain ideal system configurations for varying load parameters.}, author = {Hoßfeld, Tobias and Raffeck, Simon and Loh, Frank and Geißler, Stefan}, booktitle = {1st International Workshop on Network Energy Efficiency in the Softwarization Era}, keywords = {can}, month = 6, title = {Analytical Model for the Energy Efficiency in Low Power IoT Deployments}, year = 2022 }
DBM: Decentralized Burst Mitigation for Self-Organizing LoRa Deployments Raffeck, Simon; Geißler, Stefan; Hoßfeld, Tobias in KuVS Fachgespräch - Würzburg Workshop on Modeling, Analysis and Simulation of Next-Generation Communication Networks 2022 (2022).
- [ BibTeX ]
@inproceedings{info3-inproceedings-2022-7, author = {Raffeck, Simon and Geißler, Stefan and Hoßfeld, Tobias}, booktitle = {KuVS Fachgespräch - Würzburg Workshop on Modeling, Analysis and Simulation of Next-Generation Communication Networks 2022}, keywords = {can}, month = 7, title = {DBM: Decentralized Burst Mitigation for Self-Organizing LoRa Deployments}, year = 2022 }
Identification of Signaling Patterns in Mobile IoT Signaling Traffic Vomhoff, Viktoria; Geißler, Stefan; Hoßfeld, Tobias in WueWoWAS 22 - KuVS Fachgespräch - Würzburg Workshop on Next-Generation Communication Networks (2022).
- [ BibTeX ]
@inproceedings{info3-inproceedings-2022-8, author = {Vomhoff, Viktoria and Geißler, Stefan and Hoßfeld, Tobias}, booktitle = {WueWoWAS 22 - KuVS Fachgespräch - Würzburg Workshop on Next-Generation Communication Networks}, keywords = {can}, month = 7, title = {Identification of Signaling Patterns in Mobile IoT Signaling Traffic}, year = 2022 }
Pandemic in the Digital Age: Analyzing WhatsApp Communication Behavior before, during, and after the COVID-19 Lockdown Seufert, Anika; Poignée, Fabian; Hoßfeld, Tobias; Seufert, Michael in Humanities and Social Sciences Communications (2022). 9(1) 140 (1–9).
- [ Abstract ]
- [ BibTeX ]
The strict restrictions introduced by the COVID-19 lockdowns, which started from March 2020, changed people’s daily lives and habits on many different levels. In this work, we investigate the impact of the lockdown on the communication behavior in the mobile instant messaging application WhatsApp. Our evaluations are based on a large dataset of 2577 private chat histories with 25,378,093 messages from 51,973 users. The analysis of the one-to-one and group conversations confirms that the lockdown severely altered the communication in WhatsApp chats compared to pre-pandemic time ranges. In particular, we observe short-term effects, which caused an increased message frequency in the first lockdown months and a shifted communication activity during the day in March and April 2020. Moreover, we also see long-term effects of the ongoing pandemic situation until February 2021, which indicate a change of communication behavior towards more regular messaging, as well as a persisting change in activity during the day. The results of our work show that even anonymized chat histories can tell us a lot about people’s behavior and especially behavioral changes during the COVID-19 pandemic and thus are of great relevance for behavioral researchers. Furthermore, looking at the pandemic from an Internet provider perspective, these insights can be used during the next pandemic, or if the current COVID-19 situation worsens, to adapt communication networks to the changed usage behavior early on and thus avoid network congestion.

@article{info3-article-2022-14, abstract = {The strict restrictions introduced by the COVID-19 lockdowns, which started from March 2020, changed people’s daily lives and habits on many different levels. In this work, we investigate the impact of the lockdown on the communication behavior in the mobile instant messaging application WhatsApp. Our evaluations are based on a large dataset of 2577 private chat histories with 25,378,093 messages from 51,973 users. The analysis of the one-to-one and group conversations confirms that the lockdown severely altered the communication in WhatsApp chats compared to pre-pandemic time ranges. In particular, we observe short-term effects, which caused an increased message frequency in the first lockdown months and a shifted communication activity during the day in March and April 2020. Moreover, we also see long-term effects of the ongoing pandemic situation until February 2021, which indicate a change of communication behavior towards more regular messaging, as well as a persisting change in activity during the day. The results of our work show that even anonymized chat histories can tell us a lot about people’s behavior and especially behavioral changes during the COVID-19 pandemic and thus are of great relevance for behavioral researchers. Furthermore, looking at the pandemic from an Internet provider perspective, these insights can be used during the next pandemic, or if the current COVID-19 situation worsens, to adapt communication networks to the changed usage behavior early on and thus avoid network congestion.}, author = {Seufert, Anika and Poignée, Fabian and Hoßfeld, Tobias and Seufert, Michael}, journal = {Humanities and Social Sciences Communications}, keywords = {ucn}, month = 4, number = 1, pages = {140 (1-9)}, title = {Pandemic in the Digital Age: Analyzing WhatsApp Communication Behavior before, during, and after the COVID-19 Lockdown}, volume = 9, year = 2022 }
Virtual Reality im modernen Englischunterricht und das Potenzial für Inter- und Transkulturelles Lernen Hein, Rebecca; Steinbock, Jeanine; Eisenmann, Maria; Wienrich, Carolin; Latoschik, Marc Erich in MedienPädagogik Zeitschrift für Theorie und Praxis der Medienbildung (2022). 47 246–266.
- [ BibTeX ]
- [ URL ]
@article{hein2021medienpaed, author = {Hein, Rebecca and Steinbock, Jeanine and Eisenmann, Maria and Wienrich, Carolin and Latoschik, Marc Erich}, journal = {MedienPädagogik Zeitschrift für Theorie und Praxis der Medienbildung}, keywords = {rhein}, pages = {246-266}, title = {Virtual Reality im modernen Englischunterricht und das Potenzial für Inter- und Transkulturelles Lernen}, volume = 47, year = 2022 }
The Possibility of Inducing the Proteus Effect for Social VR Users Oyanagi, Akimi; Narumi, Takuji; Lugrin, Jean-Luc; Aoyama, Kazuma; Ito, Kenichiro; Amemiya, Tomohiro; Hirose, Michitaka in HCI International 2022 -- Late Breaking Papers: Interacting with eXtended Reality and Artificial Intelligence, J. Y. C. Chen, G. Fragomeni, H. Degen, S. Ntoa (eds.) (2022). 143–158.
- [ Abstract ]
- [ BibTeX ]
- [ URL ]
The Proteus effect in Virtual Reality (VR) happens when the user's behavior or attitude are affected by their avatar's appearance. The virtual body appearance is somehow affecting the emotional, behavioral and psychological state of its user. In recent years, manipulation of an avatar has become a more common situation because of social VR platforms. It is considered that the Proteus effect can be induced even for social VR users. However, there are possibilities to disrupt the Proteus effect by becoming accustomed to embodying an avatar or attachment to their avatar.

@inproceedings{10.1007/978-3-031-21707-4_11, abstract = {The Proteus effect in Virtual Reality (VR) happens when the user's behavior or attitude are affected by their avatar's appearance. The virtual body appearance is somehow affecting the emotional, behavioral and psychological state of its user. In recent years, manipulation of an avatar has become a more common situation because of social VR platforms. It is considered that the Proteus effect can be induced even for social VR users. However, there are possibilities to disrupt the Proteus effect by becoming accustomed to embodying an avatar or attachment to their avatar.}, address = {Cham}, author = {Oyanagi, Akimi and Narumi, Takuji and Lugrin, Jean-Luc and Aoyama, Kazuma and Ito, Kenichiro and Amemiya, Tomohiro and Hirose, Michitaka}, booktitle = {HCI International 2022 – Late Breaking Papers: Interacting with eXtended Reality and Artificial Intelligence}, editor = {Chen, Jessie Y. C. and Fragomeni, Gino and Degen, Helmut and Ntoa, Stavroula}, keywords = {social}, pages = {143–158}, publisher = {Springer Nature Switzerland}, title = {The Possibility of Inducing the Proteus Effect for Social VR Users}, year = 2022 }
The State of Serverless Applications: Collection, Characterization, and Community Consensus Eismann, Simon; Scheuner, Joel; van Eyk, Erwin; Schwinger, Maximilian; Grohmann, Johannes; Herbst, Nikolas; Abad, Cristina; Iosup, Alexandru in Transactions on Software Engineering (2022). 48(10) 4152–4166.
- [ Abstract ]
- [ BibTeX ]
- [ URL ]
Over the last five years, all major cloud platform providers have increased their serverless offerings. Many early adopters report significant benefits for serverless-based over traditional applications, and many companies are considering moving to serverless themselves. However, currently there exist only few, scattered, and sometimes even conflicting reports on when serverless applications are well suited and what the best practices for their implementation are. We address this problem in the present study about the state of serverless applications. We collect descriptions of 89 serverless applications from open-source projects, academic literature, industrial literature, and domain-specific feedback. We analyze 16 characteristics that describe why and when successful adopters are using serverless applications, and how they are building them. We further compare the results of our characterization study to 10 existing, mostly industrial, studies and datasets; this allows us to identify points of consensus across multiple studies, investigate points of disagreement, and overall confirm the validity of our results. The results of this study can help managers to decide if they should adopt serverless technology, engineers to learn about current practices of building serverless applications, and researchers and platform providers to better understand the current landscape of serverless applications.

@article{eismann2021state, abstract = {Over the last five years, all major cloud platform providers have increased their serverless offerings. Many early adopters report significant benefits for serverless-based over traditional applications, and many companies are considering moving to serverless themselves. However, currently there exist only few, scattered, and sometimes even conflicting reports on when serverless applications are well suited and what the best practices for their implementation are. We address this problem in the present study about the state of serverless applications. We collect descriptions of 89 serverless applications from open-source projects, academic literature, industrial literature, and domain-specific feedback. We analyze 16 characteristics that describe why and when successful adopters are using serverless applications, and how they are building them. We further compare the results of our characterization study to 10 existing, mostly industrial, studies and datasets; this allows us to identify points of consensus across multiple studies, investigate points of disagreement, and overall confirm the validity of our results. The results of this study can help managers to decide if they should adopt serverless technology, engineers to learn about current practices of building serverless applications, and researchers and platform providers to better understand the current landscape of serverless applications.}, author = {Eismann, Simon and Scheuner, Joel and van Eyk, Erwin and Schwinger, Maximilian and Grohmann, Johannes and Herbst, Nikolas and Abad, Cristina and Iosup, Alexandru}, journal = {Transactions on Software Engineering}, keywords = {t_journalmagazine}, number = 10, pages = {4152- 4166}, title = {The State of Serverless Applications: Collection, Characterization, and Community Consensus}, volume = 48, year = 2022 }
Designing Social Robots’ Speech in the Hotel Context-A Series of Online Studies Steinhaeusser, Sophia C.; Lein, Martina; Donnermann, Melissa; Lugrin, Birgit in 2022 31st IEEE International Conference on Robot and Human Interactive Communication (RO-MAN) (2022). 163–170.
- [ BibTeX ]
@inproceedings{steinhaeusser2022designing, author = {Steinhaeusser, Sophia C. and Lein, Martina and Donnermann, Melissa and Lugrin, Birgit}, booktitle = {2022 31st IEEE International Conference on Robot and Human Interactive Communication (RO-MAN)}, keywords = {storyteller}, organization = {IEEE}, pages = {163-170}, title = {Designing Social Robots' Speech in the Hotel Context-A Series of Online Studies}, year = 2022 }
Parametric Skin Wound Generation for Medical Simulations Schott, Christian; Hofmann, Sarah; von Mammen, Sebastian in 2022 International Conference on Interactive Media, Smart Systems and Emerging Technologies (IMET) (2022). 1–8.
- [ Abstract ]
- [ BibTeX ]
- [ URL ]
Medical simulations offer various opportunities to improve treatment training in different areas of medicine. The realism and thus effectiveness of wound care training goes hand in hand with the realism of the wounds themselves. In this paper, we propose a novel approach to (a) procedurally generate convincing-looking wound textures and (b) to dynamically project them onto animated, skinned meshes. Our method allows for creating dermal wounds of different types including abrasions, lacerations and puncture wounds. We analyzed the outcome by recreating visualization instances of these types, demonstrating the applicability of our system.

@inproceedings{9929659, abstract = {Medical simulations offer various opportunities to improve treatment training in different areas of medicine. The realism and thus effectiveness of wound care training goes hand in hand with the realism of the wounds themselves. In this paper, we propose a novel approach to (a) procedurally generate convincing-looking wound textures and (b) to dynamically project them onto animated, skinned meshes. Our method allows for creating dermal wounds of different types including abrasions, lacerations and puncture wounds. We analyzed the outcome by recreating visualization instances of these types, demonstrating the applicability of our system.}, author = {Schott, Christian and Hofmann, Sarah and von Mammen, Sebastian}, booktitle = {2022 International Conference on Interactive Media, Smart Systems and Emerging Technologies (IMET)}, keywords = {via-vr}, month = {oct}, pages = {1-8}, title = {Parametric Skin Wound Generation for Medical Simulations}, year = 2022 }
Self-Aware Optimization of Adaptation Planning Strategies Lesch, Veronika; Hadry, Marius; Kounev, Samuel; Krupitzer, Christian in ACM Transactions on Autonomous and Adaptive Systems (2022).
- [ Abstract ]
- [ BibTeX ]
- [ URL ]
In today’s world, circumstances, processes, and requirements for software systems are becoming increasingly complex. In order to operate properly in such dynamic environments, software systems must adapt to these changes, which has led to the research area of Self-Adaptive Systems (SAS). Platooning is one example of adaptive systems in Intelligent Transportation Systems, which is the ability of vehicles to travel with close inter-vehicle distances. This technology leads to an increase in road throughput and safety, which directly addresses the increased infrastructure needs due to increased traffic on the roads. However, the No-Free-Lunch theorem states that the performance of one adaptation planning strategy is not necessarily transferable to other problems. Moreover, especially in the field of SAS, the selection of the most appropriate strategy depends on the current situation of the system. In this paper, we address the problem of self-aware optimization of adaptation planning strategies by designing a framework that includes situation detection, strategy selection, and parameter optimization of the selected strategies. We apply our approach on the case study platooning coordination and evaluate the performance of the proposed framework.

@article{lesch2022selfaware, abstract = {In today’s world, circumstances, processes, and requirements for software systems are becoming increasingly complex. In order to operate properly in such dynamic environments, software systems must adapt to these changes, which has led to the research area of Self-Adaptive Systems (SAS). Platooning is one example of adaptive systems in Intelligent Transportation Systems, which is the ability of vehicles to travel with close inter-vehicle distances. This technology leads to an increase in road throughput and safety, which directly addresses the increased infrastructure needs due to increased traffic on the roads. However, the No-Free-Lunch theorem states that the performance of one adaptation planning strategy is not necessarily transferable to other problems. Moreover, especially in the field of SAS, the selection of the most appropriate strategy depends on the current situation of the system. In this paper, we address the problem of self-aware optimization of adaptation planning strategies by designing a framework that includes situation detection, strategy selection, and parameter optimization of the selected strategies. We apply our approach on the case study platooning coordination and evaluate the performance of the proposed framework.}, author = {Lesch, Veronika and Hadry, Marius and Kounev, Samuel and Krupitzer, Christian}, journal = {ACM Transactions on Autonomous and Adaptive Systems}, keywords = {myown}, month = {oct}, title = {Self-Aware Optimization of Adaptation Planning Strategies}, year = 2022 }
Experience and Guidelines for Sorting Algorithm Choices and Their Energy Efficiency Meissner, Maximilian; Kamthania, Supriya; Rawtani, Nishant; Bucek, James; Lange, Klaus-Dieter; Kounev, Samuel in Companion of the 2022 ACM/SPEC International Conference on Performance Engineering (2022).
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@inproceedings{meissner2022experience, address = {New York, NY, USA}, author = {Meissner, Maximilian and Kamthania, Supriya and Rawtani, Nishant and Bucek, James and Lange, Klaus-Dieter and Kounev, Samuel}, booktitle = {Companion of the 2022 ACM/SPEC International Conference on Performance Engineering}, keywords = {myown}, month = {April}, publisher = {ACM}, title = {Experience and Guidelines for Sorting Algorithm Choices and Their Energy Efficiency}, year = 2022 }
A data-driven Sensor Model for LIDAR Range Measurements used for Mobile Robot Navigation Spiess, Florian; Strobel, Norbert; Kaupp, Tobias; Kounev, Samuel in Proceedings of the IEEE IRC 2022 Conference (2022).
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@conference{spiess2022datadriven, author = {Spiess, Florian and Strobel, Norbert and Kaupp, Tobias and Kounev, Samuel}, booktitle = {Proceedings of the IEEE IRC 2022 Conference}, keywords = {myown}, title = {A data-driven Sensor Model for LIDAR Range Measurements used for Mobile Robot Navigation}, year = 2022 }
Experience and Guidelines for Sorting Algorithm Choices and Their Energy Efficiency Meissner, Maximilian; Kamthania, Supriya; Rawtani, Nishant; Bucek, James; Lange, Klaus-Dieter; Kounev, Samuel in Companion of the 2022 ACM/SPEC International Conference on Performance Engineering (2022).
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@inproceedings{meissner2022experience, address = {New York, NY, USA}, author = {Meissner, Maximilian and Kamthania, Supriya and Rawtani, Nishant and Bucek, James and Lange, Klaus-Dieter and Kounev, Samuel}, booktitle = {Companion of the 2022 ACM/SPEC International Conference on Performance Engineering}, keywords = {myown}, month = {April}, publisher = {ACM}, title = {Experience and Guidelines for Sorting Algorithm Choices and Their Energy Efficiency}, year = 2022 }
Mixed-Cultural Speech for Mixed-Cultural Users - Natural vs. Synthetic Speech for Virtual Agents Obremski, David; Lugrin, Birgit in HAI ’22: International Conference on Human-Agent Interaction (2022). 290–292.
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@inproceedings{Obremski_HAI_Poster_2022, author = {Obremski, David and Lugrin, Birgit}, booktitle = {HAI '22: International Conference on Human-Agent Interaction}, keywords = {obremski}, month = {dec}, pages = {290-292}, publisher = {ACM}, title = {Mixed-Cultural Speech for Mixed-Cultural Users - Natural vs. Synthetic Speech for Virtual Agents}, year = 2022 }
Mixed-Cultural Speech for Intelligent Virtual Agents - the Impact of Different Non-Native Accents Using Natural or Synthetic Speech in the English Language Obremski, David; Hering, Helena Babette; Friedrich, Paula; Lugrin, Birgit in HAI ’22: International Conference on Human-Agent Interaction (2022). 67–75.
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@inproceedings{Obremski_HAI_Paper_2022, author = {Obremski, David and Hering, Helena Babette and Friedrich, Paula and Lugrin, Birgit}, booktitle = {HAI '22: International Conference on Human-Agent Interaction}, keywords = {obremski}, month = {dec}, pages = {67-75}, publisher = {ACM}, title = {Mixed-Cultural Speech for Intelligent Virtual Agents - the Impact of Different Non-Native Accents Using Natural or Synthetic Speech in the English Language}, year = 2022 }
Second Language Learning through Storytelling with a Social Robot-An Online Case Study Steinhaeusser, Sophia C.; Riedmann, Anna; Schaper, Philipp; Guthmann, Emily; Pfister, Julia; Schmitt, Katharina; Wild, Theresa; Lugrin, Birgit in 2022 31st IEEE International Conference on Robot and Human Interactive Communication (RO-MAN) (2022). 67–74.
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@inproceedings{steinhaeusser2022second, author = {Steinhaeusser, Sophia C. and Riedmann, Anna and Schaper, Philipp and Guthmann, Emily and Pfister, Julia and Schmitt, Katharina and Wild, Theresa and Lugrin, Birgit}, booktitle = {2022 31st IEEE International Conference on Robot and Human Interactive Communication (RO-MAN)}, keywords = {storytelling}, organization = {IEEE}, pages = {67-74}, title = {Second Language Learning through Storytelling with a Social Robot-An Online Case Study}, year = 2022 }
{Investigating the Predictability of QoS Metrics in Cellular Networks} Herrnleben, Stefan; Grohmann, Johannes; Lesch, Veronika; Prantl, Thomas; Metzger, Florian; Hoßfeld, Tobias; Kounev, Samuel in 2022 IEEE/ACM 30th International Symposium on Quality of Service (IWQoS) (2022). 1–10.
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@inproceedings{HeGrLePrMeHoKo-2022-IWQoS-QoS-Prediction-Cellular-Networks, author = {Herrnleben, Stefan and Grohmann, Johannes and Lesch, Veronika and Prantl, Thomas and Metzger, Florian and Hoßfeld, Tobias and Kounev, Samuel}, booktitle = {2022 IEEE/ACM 30th International Symposium on Quality of Service (IWQoS)}, keywords = {myown}, pages = {1-10}, title = {{Investigating the Predictability of QoS Metrics in Cellular Networks}}, year = 2022 }
One Graph to Rule them All: Using {NLP} and Graph Neural Networks to analyse Tolkien’s Legendarium Perri, Vincenzo; Qarkaxhija, Lisi; Zehe, Albin; Hotho, Andreas; Scholtes, Ingo in Proceedings of the Computational Humanities Research Conference 2022, {CHR} 2022, Antwerp, Belgium, December 12-14, 2022, {CEUR} Workshop Proceedings, F. Karsdorp, K. L. Nielbo (eds.) (2022). (Vol. 3290) 291–317.
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@inproceedings{DBLP:conf/chr/PerriQZHS22, author = {Perri, Vincenzo and Qarkaxhija, Lisi and Zehe, Albin and Hotho, Andreas and Scholtes, Ingo}, booktitle = {Proceedings of the Computational Humanities Research Conference 2022, {CHR} 2022, Antwerp, Belgium, December 12-14, 2022}, editor = {Karsdorp, Folgert and Nielbo, Kristoffer L.}, keywords = {myown}, pages = {291–317}, publisher = {CEUR-WS.org}, series = {{CEUR} Workshop Proceedings}, title = {One Graph to Rule them All: Using {NLP} and Graph Neural Networks to analyse Tolkien's Legendarium}, volume = 3290, year = 2022 }
NeuralPDE: Modelling Dynamical Systems from Data Dulny, Andrzej; Hotho, Andreas; Krause, Anna in {KI} 2022: Advances in Artificial Intelligence - 45th German Conference on AI, Trier, Germany, September 19-23, 2022, Proceedings, Lecture Notes in Computer Science, R. Bergmann, L. Malburg, S. C. Rodermund, I. J. Timm (eds.) (2022). (Vol. 13404) 75–89.
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@inproceedings{DBLP:conf/ki/DulnyHK22, author = {Dulny, Andrzej and Hotho, Andreas and Krause, Anna}, booktitle = {{KI} 2022: Advances in Artificial Intelligence - 45th German Conference on AI, Trier, Germany, September 19-23, 2022, Proceedings}, editor = {Bergmann, Ralph and Malburg, Lukas and Rodermund, Stephanie C. and Timm, Ingo J.}, keywords = {myown}, pages = {75–89}, publisher = {Springer}, series = {Lecture Notes in Computer Science}, title = {NeuralPDE: Modelling Dynamical Systems from Data}, volume = 13404, year = 2022 }
Anomaly Detection in Beehives: An Algorithm Comparison Davidson, Padraig; Steininger, Michael; Lautenschlager, Florian; Krause, Anna; Hotho, Andreas in Sensor Networks, A. Ahrens, R. V. Prasad, C. Benavente-Peces, N. Ansari (eds.) (2022). 1–20.
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Sensor-equipped beehives allow monitoring the living conditions of bees. Machine learning models can use the data of such hives to learn behavioral patterns and find anomalous events. One type of event that is of particular interest to apiarists for economical reasons is bee swarming. Other events of interest are behavioral anomalies from illness and technical anomalies, e.g. sensor failure. Beekeepers can be supported by suitable machine learning models which can detect these events.

@inproceedings{10.1007/978-3-031-17718-7_1, abstract = {Sensor-equipped beehives allow monitoring the living conditions of bees. Machine learning models can use the data of such hives to learn behavioral patterns and find anomalous events. One type of event that is of particular interest to apiarists for economical reasons is bee swarming. Other events of interest are behavioral anomalies from illness and technical anomalies, e.g. sensor failure. Beekeepers can be supported by suitable machine learning models which can detect these events.}, address = {Cham}, author = {Davidson, Padraig and Steininger, Michael and Lautenschlager, Florian and Krause, Anna and Hotho, Andreas}, booktitle = {Sensor Networks}, editor = {Ahrens, Andreas and Prasad, RangaRao Venkatesha and Benavente-Peces, C{\'e}sar and Ansari, Nirwan}, keywords = {myown}, pages = {1–20}, publisher = {Springer International Publishing}, title = {Anomaly Detection in Beehives: An Algorithm Comparison}, year = 2022 }
Journey Through a Virtual Tunnel: Simulated Motion and its Effects on the Experience of Time Landeck, Maximilian; Alvarez Igarz{\’a}bal, Federico; Unruh, Fabian; Habenicht, Hannah; Khoshnoud, Shiva; Wittmann, Marc; Lugrin, Jean-Luc; Latoschik, Marc Erich in Frontiers in Virtual Reality (2022). 3 195.
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@article{landeck3journey, author = {Landeck, Maximilian and Alvarez Igarz{\'a}bal, Federico and Unruh, Fabian and Habenicht, Hannah and Khoshnoud, Shiva and Wittmann, Marc and Lugrin, Jean-Luc and Latoschik, Marc Erich}, journal = {Frontiers in Virtual Reality}, keywords = {vtimes}, pages = 195, publisher = {Frontiers}, title = {Journey Through a Virtual Tunnel: Simulated Motion and its Effects on the Experience of Time}, volume = 3, year = 2022 }
Congruence and Plausibility, not Presence?! Pivotal Conditions for XR Experiences and Effects, a Novel Model Latoschik, Marc Erich; Wienrich, Carolin in Frontiers in Virtual Reality (2022). 3:694433
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Presence is often considered the most important quale describing the subjective feeling of being in a computer-generated and/or computer-mediated virtual environment. The identification and separation of orthogonal presence components, i.e., the place illusion and the plausibility illusion, has been an accepted theoretical model describing Virtual Reality (VR) experiences for some time. This perspective article challenges this presence-oriented VR theory. First, we argue that a place illusion cannot be the major construct to describe the much wider scope of virtual, augmented, and mixed reality (VR, AR, MR: or XR for short). Second, we argue that there is no plausibility illusion but merely plausibility, and we derive the place illusion caused by the congruent and plausible generation of spatial cues and similarly for all the current model’s so-defined illusions. Finally, we propose congruence and plausibility to become the central essential conditions in a novel theoretical model describing XR experiences and effects.

@article{latoschik2021coherence, abstract = {Presence is often considered the most important quale describing the subjective feeling of being in a computer-generated and/or computer-mediated virtual environment. The identification and separation of orthogonal presence components, i.e., the place illusion and the plausibility illusion, has been an accepted theoretical model describing Virtual Reality (VR) experiences for some time. This perspective article challenges this presence-oriented VR theory. First, we argue that a place illusion cannot be the major construct to describe the much wider scope of virtual, augmented, and mixed reality (VR, AR, MR: or XR for short). Second, we argue that there is no plausibility illusion but merely plausibility, and we derive the place illusion caused by the congruent and plausible generation of spatial cues and similarly for all the current model’s so-defined illusions. Finally, we propose congruence and plausibility to become the central essential conditions in a novel theoretical model describing XR experiences and effects.}, author = {Latoschik, Marc Erich and Wienrich, Carolin}, journal = {Frontiers in Virtual Reality}, keywords = {myown}, month = {jun}, title = {Congruence and Plausibility, not Presence?! Pivotal Conditions for XR Experiences and Effects, a Novel Model}, volume = {3:694433}, year = 2022 }
{Investigating the Predictability of QoS Metrics in Cellular Networks} Herrnleben, Stefan; Grohmann, Johannes; Lesch, Veronika; Prantl, Thomas; Metzger, Florian; Hoßfeld, Tobias; Kounev, Samuel in 2022 IEEE/ACM 30th International Symposium on Quality of Service (IWQoS) (2022). 1–10.
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@inproceedings{HeGrLePrMeHoKo-2022-IWQoS-QoS-Prediction-Cellular-Networks, author = {Herrnleben, Stefan and Grohmann, Johannes and Lesch, Veronika and Prantl, Thomas and Metzger, Florian and Hoßfeld, Tobias and Kounev, Samuel}, booktitle = {2022 IEEE/ACM 30th International Symposium on Quality of Service (IWQoS)}, keywords = {myown}, pages = {1-10}, title = {{Investigating the Predictability of QoS Metrics in Cellular Networks}}, year = 2022 }
{Investigating the Predictability of QoS Metrics in Cellular Networks} Herrnleben, Stefan; Grohmann, Johannes; Lesch, Veronika; Prantl, Thomas; Metzger, Florian; Hoßfeld, Tobias; Kounev, Samuel in 2022 IEEE/ACM 30th International Symposium on Quality of Service (IWQoS) (2022). 1–10.
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@inproceedings{HeGrLePrMeHoKo-2022-IWQoS-QoS-Prediction-Cellular-Networks, author = {Herrnleben, Stefan and Grohmann, Johannes and Lesch, Veronika and Prantl, Thomas and Metzger, Florian and Hoßfeld, Tobias and Kounev, Samuel}, booktitle = {2022 IEEE/ACM 30th International Symposium on Quality of Service (IWQoS)}, keywords = {myown}, pages = {1-10}, title = {{Investigating the Predictability of QoS Metrics in Cellular Networks}}, year = 2022 }
Self-Touch: An Immersive Interaction-Technique to Enhance Body Awareness Keppler, Sebastian; Döllinger, Nina; Wienrich, Carolin; Latoschik, Marc Erich; Israel, Johann Habakuk in i-com (2022). 21(3) 329–337.
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Physical well-being depends essentially on how the own body is perceived. A missing correspondence between the perception of one’s own body and reality can be distressing and eventually lead to mental illness. The touch of the own body is a multi-sensory experience to strengthen the feeling of the own body. We have developed an interaction technique that allows the self-touch of the own body in an immersive environment to support therapy procedures. Through additional visual feedback, we want to strengthen the feeling for the own body to achieve a sustainable effect in the own body perception. We conducted an expert evaluation to analyse the potential impact of our application and to localize and fix possible usability problems. The experts noted the ease of understanding and suitability of the interaction technique for increasing body awareness. However, the technical challenges such as stable and accurate body tracking were also mentioned. In addition, new ideas were given that would further support body awareness.

@article{KepplerDöllingerWienrichLatoschikIsrael+2022+329+337, abstract = {Physical well-being depends essentially on how the own body is perceived. A missing correspondence between the perception of one’s own body and reality can be distressing and eventually lead to mental illness. The touch of the own body is a multi-sensory experience to strengthen the feeling of the own body. We have developed an interaction technique that allows the self-touch of the own body in an immersive environment to support therapy procedures. Through additional visual feedback, we want to strengthen the feeling for the own body to achieve a sustainable effect in the own body perception. We conducted an expert evaluation to analyse the potential impact of our application and to localize and fix possible usability problems. The experts noted the ease of understanding and suitability of the interaction technique for increasing body awareness. However, the technical challenges such as stable and accurate body tracking were also mentioned. In addition, new ideas were given that would further support body awareness.}, author = {Keppler, Sebastian and Döllinger, Nina and Wienrich, Carolin and Latoschik, Marc Erich and Israel, Johann Habakuk}, journal = {i-com}, keywords = {vitras}, number = 3, pages = {329–337}, title = {Self-Touch: An Immersive Interaction-Technique to Enhance Body Awareness}, volume = 21, year = 2022 }
A data-driven Sensor Model for LIDAR Range Measurements used for Mobile Robot Navigation Spiess, Florian; Strobel, Norbert; Kaupp, Tobias; Kounev, Samuel in Proceedings of the IEEE IRC 2022 Conference (2022).
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@conference{spiess2022datadriven, author = {Spiess, Florian and Strobel, Norbert and Kaupp, Tobias and Kounev, Samuel}, booktitle = {Proceedings of the IEEE IRC 2022 Conference}, keywords = {myown}, title = {A data-driven Sensor Model for LIDAR Range Measurements used for Mobile Robot Navigation}, year = 2022 }
Ransomware Detection in Databases through Dynamic Analysis of Query Sequences Sendner, Christoph; Iffländer, Lukas; Schindler, Sebastian; Jobst, Michael; Dmitrienko, Alexandra; Kounev, Samuel in 2022 IEEE Conference on Communications and Network Security (CNS) (2022).
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@conference{sendner2022ransomware, author = {Sendner, Christoph and Iffländer, Lukas and Schindler, Sebastian and Jobst, Michael and Dmitrienko, Alexandra and Kounev, Samuel}, booktitle = {2022 IEEE Conference on Communications and Network Security (CNS)}, keywords = {sss-group}, title = {Ransomware Detection in Databases through Dynamic Analysis of Query Sequences}, year = 2022 }
Leveraging Kubernetes Source Code for Performance Simulation Straesser, Martin; Haas, Patrick (2022).
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@presentation{straesser2022leveraging, author = {Straesser, Martin and Haas, Patrick}, keywords = {myown}, title = {Leveraging Kubernetes Source Code for Performance Simulation}, year = 2022 }
LoRaWAN Network Planning in Smart Environments: Towards Reliability, Scalability, and Cost Reduction Loh, Frank; Geißler, Stefan; Hoßfeld, Tobias in WueWoWAS 22 - KuVS Fachgespräch - Würzburg Workshop on Next-Generation Communication Networks (2022).
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The goal in this work is to present a guidance for LoRaWAN planning to improve overall reliability for message transmissions and scalability. At the end, the cost component is discussed. Therefore, a five step approach is presented that helps to plan a LoRaWAN deployment step by step: Based on the device locations, an initial gateway placement is suggested followed by in-depth frequency and channel access planning. After an initial planning phase, updates for channel access and the initial gateway planning is suggested that should also be done periodically during network operation. Since current gateway placement approaches are only studied with random channel access, there is a lot of potential in the cell planning phase. Furthermore, the performance of different channel access approaches is highly related on network load, and thus cell size and sensor density. Last, the influence of different cell planning ideas on expected costs are discussed.

@inproceedings{info3-inproceedings-2022-20, abstract = {The goal in this work is to present a guidance for LoRaWAN planning to improve overall reliability for message transmissions and scalability. At the end, the cost component is discussed. Therefore, a five step approach is presented that helps to plan a LoRaWAN deployment step by step: Based on the device locations, an initial gateway placement is suggested followed by in-depth frequency and channel access planning. After an initial planning phase, updates for channel access and the initial gateway planning is suggested that should also be done periodically during network operation. Since current gateway placement approaches are only studied with random channel access, there is a lot of potential in the cell planning phase. Furthermore, the performance of different channel access approaches is highly related on network load, and thus cell size and sensor density. Last, the influence of different cell planning ideas on expected costs are discussed.}, author = {Loh, Frank and Geißler, Stefan and Hoßfeld, Tobias}, booktitle = {WueWoWAS 22 - KuVS Fachgespräch - Würzburg Workshop on Next-Generation Communication Networks}, keywords = {5mart}, month = 7, title = {LoRaWAN Network Planning in Smart Environments: Towards Reliability, Scalability, and Cost Reduction}, year = 2022 }
Graph-Based Gateway Placement for Better Performance in LoRaWAN Deployments Loh, Frank; Mehling, Noah; Geißler, Stefan; Hoßfeld, Tobias in 20th Mediterranean Communication and Computer Networking Conference (MedComNet) (2022).
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Low Power Wide Area Networks with Long Range Wide Area Networks (LoRaWANs) as one of their most prominent representatives are very promising solutions for future Internet of Things deployments. The technology is characterized by low energy requirements leading to long battery lifetimes. However, the drawback is very limited throughput rates. However, the unreliable nature of the LoRa technology is hindering the adoption. Especially its random channel access approach leads to significant message collisions and thus, data loss in larger deployments. From a network planning point of view, one possibility to deal with collisions is the reduction of potentially colliding messages at the frequency bands in combination with limiting the transmission duration of messages. For that reason, we present a novel graph-based gateway placement approach. The main focus is collision probability reduction, which directly increases reliability in LoRaWAN deployments. We show that our approach performs similar to state-of-the-art related work in the worst case and reduces the required number of gateways by up to 40% while reducing the collision probability by up to 70%. Furthermore, we discuss the scalability of our approach to cover arbitrarily large networks with gateways and only little overhead by splitting the problem into smaller sub-problems.

@inproceedings{info3-inproceedings-2022-19, abstract = {Low Power Wide Area Networks with Long Range Wide Area Networks (LoRaWANs) as one of their most prominent representatives are very promising solutions for future Internet of Things deployments. The technology is characterized by low energy requirements leading to long battery lifetimes. However, the drawback is very limited throughput rates. However, the unreliable nature of the LoRa technology is hindering the adoption. Especially its random channel access approach leads to significant message collisions and thus, data loss in larger deployments. From a network planning point of view, one possibility to deal with collisions is the reduction of potentially colliding messages at the frequency bands in combination with limiting the transmission duration of messages. For that reason, we present a novel graph-based gateway placement approach. The main focus is collision probability reduction, which directly increases reliability in LoRaWAN deployments. We show that our approach performs similar to state-of-the-art related work in the worst case and reduces the required number of gateways by up to 40% while reducing the collision probability by up to 70%. Furthermore, we discuss the scalability of our approach to cover arbitrarily large networks with gateways and only little overhead by splitting the problem into smaller sub-problems.}, author = {Loh, Frank and Mehling, Noah and Geißler, Stefan and Hoßfeld, Tobias}, booktitle = {20th Mediterranean Communication and Computer Networking Conference (MedComNet)}, keywords = {5mart}, month = 6, title = {Graph-Based Gateway Placement for Better Performance in LoRaWAN Deployments}, year = 2022 }
Generic Model to Quantify Energy Consumption for Different LoRaWAN Channel Access Methods Loh, Frank; Raffeck, Simon; Geißler, Stefan; Hoßfeld, Tobias in 18th International Conference on Wireless and Mobile Computing, Networking and Communications (WiMob) (2022).
- [ Abstract ]
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LoRaWAN is one of the most promising Internet of Things technologies with regard to low energy consumption. However, the currently used random channel access has much potential for improvement. Thus, current literature studies alternative channel access approaches, but the energy consumption is often not taken into consideration. For that reason, we present a generic model to quantify energy consumption in LoRaWAN for different channel access mechanisms based on a state machine. With our model, we can describe the energy consumption for specific access mechanisms or for the complete network. Our model shows that random access only performs best if no additional receive windows are opened. A simple improvement is Listen before Talk. For networks with high load, improvements are achieved by a more complex scheduled MAC. Our model serves as a basis for future energy consumption studies, conducted through measurements or simulations.

@inproceedings{info3-inproceedings-2022-21, abstract = {LoRaWAN is one of the most promising Internet of Things technologies with regard to low energy consumption. However, the currently used random channel access has much potential for improvement. Thus, current literature studies alternative channel access approaches, but the energy consumption is often not taken into consideration. For that reason, we present a generic model to quantify energy consumption in LoRaWAN for different channel access mechanisms based on a state machine. With our model, we can describe the energy consumption for specific access mechanisms or for the complete network. Our model shows that random access only performs best if no additional receive windows are opened. A simple improvement is Listen before Talk. For networks with high load, improvements are achieved by a more complex scheduled MAC. Our model serves as a basis for future energy consumption studies, conducted through measurements or simulations.}, author = {Loh, Frank and Raffeck, Simon and Geißler, Stefan and Hoßfeld, Tobias}, booktitle = {18th International Conference on Wireless and Mobile Computing, Networking and Communications (WiMob)}, keywords = {5mart}, month = 10, title = {Generic Model to Quantify Energy Consumption for Different LoRaWAN Channel Access Methods}, year = 2022 }
InDiReCT: Language-Guided Zero-Shot Deep Metric Learning for Images Kobs, Konstantin; Steininger, Michael; Hotho, Andreas (2022).
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Common Deep Metric Learning (DML) datasets specify only one notion of similarity, e.g., two images in the Cars196 dataset are deemed similar if they show the same car model. We argue that depending on the application, users of image retrieval systems have different and changing similarity notions that should be incorporated as easily as possible. Therefore, we present Language-Guided Zero-Shot Deep Metric Learning (LanZ-DML) as a new DML setting in which users control the properties that should be important for image representations without training data by only using natural language. To this end, we propose InDiReCT (Image representations using Dimensionality Reduction on CLIP embedded Texts), a model for LanZ-DML on images that exclusively uses a few text prompts for training. InDiReCT utilizes CLIP as a fixed feature extractor for images and texts and transfers the variation in text prompt embeddings to the image embedding space. Extensive experiments on five datasets and overall thirteen similarity notions show that, despite not seeing any images during training, InDiReCT performs better than strong baselines and approaches the performance of fully-supervised models. An analysis reveals that InDiReCT learns to focus on regions of the image that correlate with the desired similarity notion, which makes it a fast to train and easy to use method to create custom embedding spaces only using natural language.

@misc{kobs2022indirect, abstract = {Common Deep Metric Learning (DML) datasets specify only one notion of similarity, e.g., two images in the Cars196 dataset are deemed similar if they show the same car model. We argue that depending on the application, users of image retrieval systems have different and changing similarity notions that should be incorporated as easily as possible. Therefore, we present Language-Guided Zero-Shot Deep Metric Learning (LanZ-DML) as a new DML setting in which users control the properties that should be important for image representations without training data by only using natural language. To this end, we propose InDiReCT (Image representations using Dimensionality Reduction on CLIP embedded Texts), a model for LanZ-DML on images that exclusively uses a few text prompts for training. InDiReCT utilizes CLIP as a fixed feature extractor for images and texts and transfers the variation in text prompt embeddings to the image embedding space. Extensive experiments on five datasets and overall thirteen similarity notions show that, despite not seeing any images during training, InDiReCT performs better than strong baselines and approaches the performance of fully-supervised models. An analysis reveals that InDiReCT learns to focus on regions of the image that correlate with the desired similarity notion, which makes it a fast to train and easy to use method to create custom embedding spaces only using natural language.}, author = {Kobs, Konstantin and Steininger, Michael and Hotho, Andreas}, keywords = {zero}, note = {cite arxiv:2211.12760Comment: Accepted to WACV 2023}, title = {InDiReCT: Language-Guided Zero-Shot Deep Metric Learning for Images}, year = 2022 }
Does Distance Matter? Embodiment and Perception of Personalized Avatars in Relation to the Self-Observation Distance in Virtual Reality Wolf, Erik; Döllinger, Nina; Mal, David; Wenninger, Stephan; Bartl, Andrea; Botsch, Mario; Latoschik, Marc Erich; Wienrich, Carolin in Frontiers in Virtual Reality (2022). 3
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Virtual reality applications employing avatar embodiment typically use virtual mirrors to allow users to perceive their digital selves not only from a first-person perspective but also from a holistic third-person view. However, due to distance-related biases such as the distance compression effect or a reduced relative rendering resolution, the self-observation distance (SOD) between the user and the virtual mirror might influence how users perceive their embodied avatar. Our article systematically investigates the effects of a short (1 meter), middle (2.5 meter), and far (4 meter) SOD between user and mirror on the perception of personalized and self-embodied avatars. The avatars were photorealistic reconstructed using state-of-the-art photogrammetric methods. Thirty participants were repeatedly exposed to their real-time animated self-embodied avatars in each of the three SOD conditions. In each condition, the personalized avatars were repeatedly altered in their body weight, and participants were asked to judge the (1) sense of embodiment, (2) body weight perception, and (3) affective appraisal towards their avatar. We found that the different SODs are unlikely to influence any of our measures except for the perceived body weight estimation difficulty. Here, the participants judged the difficulty significantly higher for the farthest SOD. We further found that the participants' self-esteem significantly impacted their ability to modify their avatar's body weight to their current body weight and that it positively correlated with the perceived attractiveness of the avatar. Additionally, the participants' concerns about their body shape affected how eerie they perceived their avatars. Both measures influenced the perceived body weight estimation difficulty. For practical application, we conclude that the virtual mirror in embodiment scenarios can be freely placed and varied at a distance of one to four meters from the user without expecting major effects on the perception of the avatar.

@article{wolf2022distance, abstract = {Virtual reality applications employing avatar embodiment typically use virtual mirrors to allow users to perceive their digital selves not only from a first-person perspective but also from a holistic third-person view. However, due to distance-related biases such as the distance compression effect or a reduced relative rendering resolution, the self-observation distance (SOD) between the user and the virtual mirror might influence how users perceive their embodied avatar. Our article systematically investigates the effects of a short (1 meter), middle (2.5 meter), and far (4 meter) SOD between user and mirror on the perception of personalized and self-embodied avatars. The avatars were photorealistic reconstructed using state-of-the-art photogrammetric methods. Thirty participants were repeatedly exposed to their real-time animated self-embodied avatars in each of the three SOD conditions. In each condition, the personalized avatars were repeatedly altered in their body weight, and participants were asked to judge the (1) sense of embodiment, (2) body weight perception, and (3) affective appraisal towards their avatar. We found that the different SODs are unlikely to influence any of our measures except for the perceived body weight estimation difficulty. Here, the participants judged the difficulty significantly higher for the farthest SOD. We further found that the participants' self-esteem significantly impacted their ability to modify their avatar's body weight to their current body weight and that it positively correlated with the perceived attractiveness of the avatar. Additionally, the participants' concerns about their body shape affected how eerie they perceived their avatars. Both measures influenced the perceived body weight estimation difficulty. For practical application, we conclude that the virtual mirror in embodiment scenarios can be freely placed and varied at a distance of one to four meters from the user without expecting major effects on the perception of the avatar.}, author = {Wolf, Erik and Döllinger, Nina and Mal, David and Wenninger, Stephan and Bartl, Andrea and Botsch, Mario and Latoschik, Marc Erich and Wienrich, Carolin}, journal = {Frontiers in Virtual Reality}, keywords = {vitras}, title = {Does Distance Matter? Embodiment and Perception of Personalized Avatars in Relation to the Self-Observation Distance in Virtual Reality}, volume = 3, year = 2022 }
Exploratory Study on the Perception of Intelligent Virtual Agents With Non-Native Accents Using Synthetic and Natural Speech in German Obremski, David; Hering, Helena Babette; Friedrich, Paula; Lugrin, Birgit in INTERNATIONAL CONFERENCE ON MULTIMODAL INTERACTION (2022).
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@inproceedings{Obremski_2022, author = {Obremski, David and Hering, Helena Babette and Friedrich, Paula and Lugrin, Birgit}, booktitle = {INTERNATIONAL CONFERENCE ON MULTIMODAL INTERACTION}, keywords = {obremski}, month = {nov}, publisher = {ACM}, title = {Exploratory Study on the Perception of Intelligent Virtual Agents With Non-Native Accents Using Synthetic and Natural Speech in German}, year = 2022 }
The impact of mixed-cultural speech on the stereotypical perception of a virtual robot Obremski, David; Friedrich, Paula; Haak, Nora; Schaper, Philipp; Lugrin, Birgit in Frontiers in Robotics and AI (2022). 9
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@article{Obremski_2022, author = {Obremski, David and Friedrich, Paula and Haak, Nora and Schaper, Philipp and Lugrin, Birgit}, journal = {Frontiers in Robotics and AI}, keywords = {schaper}, month = {nov}, publisher = {Frontiers Media SA}, title = {The impact of mixed-cultural speech on the stereotypical perception of a virtual robot}, volume = 9, year = 2022 }
Repeated experience or a virtual nose to reduce simulator sickness? Investigating prediction of the sensorial conflict theory and the rest-frame hypothesis in two virtual games Wienrich, Carolin; Obremski, David; Israel, Johann Habakuk in Entertainment Computing (2022). 43 100514.
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@article{Wienrich_2022, author = {Wienrich, Carolin and Obremski, David and Israel, Johann Habakuk}, journal = {Entertainment Computing}, keywords = {obremski}, month = {aug}, pages = 100514, publisher = {Elsevier {BV}}, title = {Repeated experience or a virtual nose to reduce simulator sickness? Investigating prediction of the sensorial conflict theory and the rest-frame hypothesis in two virtual games}, volume = 43, year = 2022 }
MiSim: A Simulator for Resilience Assessment of Microservice-based Architectures Frank, Sebastian; Wagner, Lion; Hakamian, Alireza; Straesser, Martin; van Hoorn, Andre in 2022 IEEE 22nd International Conference on Software Quality, Reliability and Security (QRS) (2022). 1014–1025.
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Increased resilience compared to monolithic architectures is both one of the key promises of microservice-based architectures and a big challenge, e.g., due to the systems’ distributed nature. Resilience assessment through simulation requires fewer resources than the measurement-based techniques used in practice. However, there is no existing simulation approach that is suitable for a holistic resilience assessment of microservices comprised of (i) representative fault injections, (ii) common resilience mechanisms, and (iii) time-varying workloads. This paper presents MiSim — an extensible simulator for resilience assessment of microservice-based architectures. It overcomes the stated limitations of related work. MiSim fits resilience engineering practices by supporting scenario-based experiments and requiring only lightweight input models. We demonstrate how MiSim simulates (1) common resilience mechanisms — i.e., circuit breaker, connection limiter, retry, load balancer, and autoscaler — and (2) fault injections — i.e., instance/service killing and latency injections. In addition, we use TeaStore, a reference microservice-based architecture, aiming to reproduce scaling behavior from an experiment by using simulation. Our results show that MiSim allows for quantitative insights into microservice-based systems’ complex transient behavior by providing up to 25 metrics.

@inproceedings{FrankWagnerHakamianStraesserVanHoorn2022MiSim, abstract = {Increased resilience compared to monolithic architectures is both one of the key promises of microservice-based architectures and a big challenge, e.g., due to the systems’ distributed nature. Resilience assessment through simulation requires fewer resources than the measurement-based techniques used in practice. However, there is no existing simulation approach that is suitable for a holistic resilience assessment of microservices comprised of (i) representative fault injections, (ii) common resilience mechanisms, and (iii) time-varying workloads. This paper presents MiSim — an extensible simulator for resilience assessment of microservice-based architectures. It overcomes the stated limitations of related work. MiSim fits resilience engineering practices by supporting scenario-based experiments and requiring only lightweight input models. We demonstrate how MiSim simulates (1) common resilience mechanisms — i.e., circuit breaker, connection limiter, retry, load balancer, and autoscaler — and (2) fault injections — i.e., instance/service killing and latency injections. In addition, we use TeaStore, a reference microservice-based architecture, aiming to reproduce scaling behavior from an experiment by using simulation. Our results show that MiSim allows for quantitative insights into microservice-based systems’ complex transient behavior by providing up to 25 metrics.}, author = {Frank, Sebastian and Wagner, Lion and Hakamian, Alireza and Straesser, Martin and van Hoorn, Andre}, booktitle = {2022 IEEE 22nd International Conference on Software Quality, Reliability and Security (QRS)}, keywords = {myown}, pages = {1014-1025}, publisher = {IEEE}, title = {MiSim: A Simulator for Resilience Assessment of Microservice-based Architectures}, year = 2022 }
Automated Blendshape Personalization for Faithful Face Animations Using Commodity Smartphones Menzel, Timo; Botsch, Mario; Latoschik, Marc Erich in Proceedings of the 28th ACM Symposium on Virtual Reality Software and Technology (VRST ’22) (2022).
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Digital reconstruction of humans has various interesting use-cases. Animated virtual humans, avatars and agents alike, are the central entities in virtual embodied human-computer and human-human encounters in social XR. Here, a faithful reconstruction of facial expressions becomes paramount due to their prominent role in non-verbal behavior and social interaction. Current XR-platforms, like Unity 3D or the Unreal Engine, integrate recent smartphone technologies to animate faces of virtual humans by facial motion capturing. Using the same technology, this article presents an optimization-based approach to generate personalized blendshapes as animation targets for facial expressions. The proposed method combines a position-based optimization with a seamless partial deformation transfer, necessary for a faithful reconstruction. Our method is fully automated and considerably outperforms existing solutions based on example-based facial rigging or deformation transfer, and overall results in a much lower reconstruction error. It also neatly integrates with recent smartphone-based reconstruction pipelines for mesh generation and automated rigging, further paving the way to a widespread application of human-like and personalized avatars and agents in various use-cases.

@inproceedings{menzel2022automated, abstract = {Digital reconstruction of humans has various interesting use-cases. Animated virtual humans, avatars and agents alike, are the central entities in virtual embodied human-computer and human-human encounters in social XR. Here, a faithful reconstruction of facial expressions becomes paramount due to their prominent role in non-verbal behavior and social interaction. Current XR-platforms, like Unity 3D or the Unreal Engine, integrate recent smartphone technologies to animate faces of virtual humans by facial motion capturing. Using the same technology, this article presents an optimization-based approach to generate personalized blendshapes as animation targets for facial expressions. The proposed method combines a position-based optimization with a seamless partial deformation transfer, necessary for a faithful reconstruction. Our method is fully automated and considerably outperforms existing solutions based on example-based facial rigging or deformation transfer, and overall results in a much lower reconstruction error. It also neatly integrates with recent smartphone-based reconstruction pipelines for mesh generation and automated rigging, further paving the way to a widespread application of human-like and personalized avatars and agents in various use-cases.}, address = {New York, NY, USA}, author = {Menzel, Timo and Botsch, Mario and Latoschik, Marc Erich}, booktitle = {Proceedings of the 28th ACM Symposium on Virtual Reality Software and Technology (VRST ’22)}, keywords = {via-vr}, number = 22, publisher = {Association for Computing Machinery}, title = {Automated Blendshape Personalization for Faithful Face Animations Using Commodity Smartphones}, year = 2022 }
Investigating Adaptive Robot Tutoring in a Long-Term Interaction in Higher Education Donnermann, Melissa; Schaper, Philipp; Lugrin, Birgit in 31st IEEE International Conference on Robot and Human Interactive Communication (RO-MAN 2022) (2022). 171–178.
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@inproceedings{donnermann2022investigating, author = {Donnermann, Melissa and Schaper, Philipp and Lugrin, Birgit}, booktitle = {31st IEEE International Conference on Robot and Human Interactive Communication (RO-MAN 2022)}, keywords = {schaper}, organization = {IEEE}, pages = {171-178}, title = {Investigating Adaptive Robot Tutoring in a Long-Term Interaction in Higher Education}, year = 2022 }
Digital body, identity and privacy in social virtual reality: A systematic review Lin, Jinghuai; Latoschik, Marc Erich in Frontiers in Virtual Reality (2022). 3
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Social Virtual Reality (social VR or SVR) provides digital spaces for diverse human activities, social interactions, and embodied face-to-face encounters. While our digital bodies in SVR can in general be of almost any conceivable appearance, individualized or even personalized avatars bearing users’ likeness recently became an interesting research topic. Such digital bodies show a great potential to enhance the authenticity of social VR citizens and increase the trustworthiness of interpersonal interaction. However, using such digital bodies might expose users to privacy and identity issues such as identity theft: For instance, how do we know whether the avatars we encounter in the virtual world are who they claim to be? Safeguarding users’ identities and privacy, and preventing harm from identity infringement, are crucial to the future of social VR. This article provides a systematic review on the protection of users’ identity and privacy in social VR, with a specific focus on digital bodies. Based on 814 sources, we identified and analyzed 49 papers that either: 1) discuss or raise concerns about the addressed issues, 2) provide technologies and potential solutions for protecting digital bodies, or 3) examine the relationship between the digital bodies and users of social VR citizens. We notice a severe lack of research and attention on the addressed topic and identify several research gaps that need to be filled. While some legal and ethical concerns about the potential identity issues of the digital bodies have been raised, and despite some progress in specific areas such as user authentication has been made, little research has proposed practical solutions. Finally, we suggest potential future research directions for digital body protection and include relevant research that might provide insights. We hope this work could provide a good overview of the existing discussion, potential solutions, and future directions for researchers with similar concerns. We also wish to draw attention to identity and privacy issues in social VR and call for interdisciplinary collaboration.

@article{lin2022digital, abstract = {Social Virtual Reality (social VR or SVR) provides digital spaces for diverse human activities, social interactions, and embodied face-to-face encounters. While our digital bodies in SVR can in general be of almost any conceivable appearance, individualized or even personalized avatars bearing users’ likeness recently became an interesting research topic. Such digital bodies show a great potential to enhance the authenticity of social VR citizens and increase the trustworthiness of interpersonal interaction. However, using such digital bodies might expose users to privacy and identity issues such as identity theft: For instance, how do we know whether the avatars we encounter in the virtual world are who they claim to be? Safeguarding users’ identities and privacy, and preventing harm from identity infringement, are crucial to the future of social VR. This article provides a systematic review on the protection of users’ identity and privacy in social VR, with a specific focus on digital bodies. Based on 814 sources, we identified and analyzed 49 papers that either: 1) discuss or raise concerns about the addressed issues, 2) provide technologies and potential solutions for protecting digital bodies, or 3) examine the relationship between the digital bodies and users of social VR citizens. We notice a severe lack of research and attention on the addressed topic and identify several research gaps that need to be filled. While some legal and ethical concerns about the potential identity issues of the digital bodies have been raised, and despite some progress in specific areas such as user authentication has been made, little research has proposed practical solutions. Finally, we suggest potential future research directions for digital body protection and include relevant research that might provide insights. We hope this work could provide a good overview of the existing discussion, potential solutions, and future directions for researchers with similar concerns. We also wish to draw attention to identity and privacy issues in social VR and call for interdisciplinary collaboration.}, author = {Lin, Jinghuai and Latoschik, Marc Erich}, journal = {Frontiers in Virtual Reality}, keywords = {prima}, title = {Digital body, identity and privacy in social virtual reality: A systematic review}, volume = 3, year = 2022 }
CortexVR: Immersive analysis and training of cognitive executive functions of soccer players using virtual reality and machine learning Krupitzer, Christian; Naber, Jens; Stauffert, Jan-Philipp; Mayer, Jan; Spielmann, Jan; Ehmann, Paul; Boci, Noel; B{\"u}rkle, Maurice; Ho, Andr{\’e}; Komorek, Clemens; Heinickel, Felix; Kounev, Samuel; Becker, Christian; Latoschik, Marc Erich in Frontiers in Psychology (2022). 5139.
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@article{krupitzer2022cortexvr, author = {Krupitzer, Christian and Naber, Jens and Stauffert, Jan-Philipp and Mayer, Jan and Spielmann, Jan and Ehmann, Paul and Boci, Noel and B{\"u}rkle, Maurice and Ho, Andr{\'e} and Komorek, Clemens and Heinickel, Felix and Kounev, Samuel and Becker, Christian and Latoschik, Marc Erich}, journal = {Frontiers in Psychology}, keywords = {myown}, pages = 5139, publisher = {Frontiers}, title = {CortexVR: Immersive analysis and training of cognitive executive functions of soccer players using virtual reality and machine learning}, year = 2022 }
Addressing Waste Separation With a Persuasive Augmented Reality App Schaper, Philipp; Riedmann, Anna; Oberdörfer, Sebastian; Lugrin, Birgit in Proceedings of the 24th International Conference on Mobile Human-Computer Interaction (MobileHCI ’22) (2022).
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@inproceedings{schaper2022addressing, address = {New York, NY, USA}, author = {Schaper, Philipp and Riedmann, Anna and Oberdörfer, Sebastian and Lugrin, Birgit}, booktitle = {Proceedings of the 24th International Conference on Mobile Human-Computer Interaction (MobileHCI '22)}, keywords = {schaper}, publisher = {Association for Computing Machinery}, title = {Addressing Waste Separation With a Persuasive Augmented Reality App}, year = 2022 }
Fingerprinting Webpages and Smartphone Apps from Encrypted Network Traffic with WebScanner Casas, Pedro; Wehner, Nikolas; Wassermann, Sarah; Seufert, Michael in Global Internet (GI) Symposium (2022).
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The wide adoption of end-to-end encryption drastically limits the visibility Internet Service Providers (ISPs) have on the services consumed by their customers. This is particularly challenging for monitoring and analysis of web and apps traffic, which is highly complex and heterogeneous. Loading a web page or app today requires tens of flows to download the various resources located in distributed cloud servers from different content providers. We introduce WebScanner, a webpage and app fingerprinting approach capable to identify all the traffic flows corresponding to individual webpage and app loading sessions within concurrent web pages traffic, enabling highly detailed, per webpage analysis in practical deployments. Different from the state of the art in web and app traffic fingerprinting, and as our most relevant contribution, WebScanner automatically performs the parsing of all the traffic generated by a web visit and its isolation from concurrent traffic, instead of assuming that an external oracle system does so. WebScanner also implements a deep fingerprinting approach to detect user action-dependent traffic from apps, relying on simple machine learning models and strong input features as fingerprints. Extensive evaluation across a large measurement dataset of popular webpages and mobile apps confirms the outstanding performance of WebScanner, identifying the top-500 Alexa websites with precision and recall (P/R) above 95%, isolating their full contents with P/R above 80% for up to 15 concurrent webpages, and detecting specific action-dependent apps traffic with average P/R above 92%.

@inproceedings{info3-inproceedings-2022-18, abstract = {The wide adoption of end-to-end encryption drastically limits the visibility Internet Service Providers (ISPs) have on the services consumed by their customers. This is particularly challenging for monitoring and analysis of web and apps traffic, which is highly complex and heterogeneous. Loading a web page or app today requires tens of flows to download the various resources located in distributed cloud servers from different content providers. We introduce WebScanner, a webpage and app fingerprinting approach capable to identify all the traffic flows corresponding to individual webpage and app loading sessions within concurrent web pages traffic, enabling highly detailed, per webpage analysis in practical deployments. Different from the state of the art in web and app traffic fingerprinting, and as our most relevant contribution, WebScanner automatically performs the parsing of all the traffic generated by a web visit and its isolation from concurrent traffic, instead of assuming that an external oracle system does so. WebScanner also implements a deep fingerprinting approach to detect user action-dependent traffic from apps, relying on simple machine learning models and strong input features as fingerprints. Extensive evaluation across a large measurement dataset of popular webpages and mobile apps confirms the outstanding performance of WebScanner, identifying the top-500 Alexa websites with precision and recall (P/R) above 95%, isolating their full contents with P/R above 80% for up to 15 concurrent webpages, and detecting specific action-dependent apps traffic with average P/R above 92%.}, address = {Paris, France}, author = {Casas, Pedro and Wehner, Nikolas and Wassermann, Sarah and Seufert, Michael}, booktitle = {Global Internet (GI) Symposium}, keywords = {ucn}, month = 11, title = {Fingerprinting Webpages and Smartphone Apps from Encrypted Network Traffic with WebScanner}, year = 2022 }
Comparison of Data Encodings and Machine Learning Architectures for User Identification on Arbitrary Motion Sequences Rack, Christian; Hotho, Andreas; Latoschik, Marc Erich in Proceedings of the IEEE International conference on artificial intelligence & Virtual Reality (IEEE AIVR) (2022).
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@inproceedings{schell2022comparison, author = {Rack, Christian and Hotho, Andreas and Latoschik, Marc Erich}, booktitle = {Proceedings of the IEEE International conference on artificial intelligence & Virtual Reality (IEEE AIVR)}, keywords = {schell}, publisher = {IEEE}, title = {Comparison of Data Encodings and Machine Learning Architectures for User Identification on Arbitrary Motion Sequences}, year = 2022 }
Addressing Motivation in an E-Learning Scenario by applying Narration and Choice Schaper, Philipp; Riedmann, Anna; Semineth, Miriam; Lugrin, Birgit in Proceedings of the 35th British Human-Computer Interaction Conference (BCS HCI 22) (2022).
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@inproceedings{schaper2022addressing, author = {Schaper, Philipp and Riedmann, Anna and Semineth, Miriam and Lugrin, Birgit}, booktitle = {Proceedings of the 35th British Human-Computer Interaction Conference (BCS HCI 22)}, keywords = {schaper}, title = {Addressing Motivation in an E-Learning Scenario by applying Narration and Choice}, year = 2022 }
Self-Aware Optimization of Adaptation Planning Strategies Lesch, Veronika; Hadry, Marius; Kounev, Samuel; Krupitzer, Christian in ACM Transactions on Autonomous and Adaptive Systems (2022).
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In today’s world, circumstances, processes, and requirements for software systems are becoming increasingly complex. In order to operate properly in such dynamic environments, software systems must adapt to these changes, which has led to the research area of Self-Adaptive Systems (SAS). Platooning is one example of adaptive systems in Intelligent Transportation Systems, which is the ability of vehicles to travel with close inter-vehicle distances. This technology leads to an increase in road throughput and safety, which directly addresses the increased infrastructure needs due to increased traffic on the roads. However, the No-Free-Lunch theorem states that the performance of one adaptation planning strategy is not necessarily transferable to other problems. Moreover, especially in the field of SAS, the selection of the most appropriate strategy depends on the current situation of the system. In this paper, we address the problem of self-aware optimization of adaptation planning strategies by designing a framework that includes situation detection, strategy selection, and parameter optimization of the selected strategies. We apply our approach on the case study platooning coordination and evaluate the performance of the proposed framework.

@article{lesch2022selfaware, abstract = {In today’s world, circumstances, processes, and requirements for software systems are becoming increasingly complex. In order to operate properly in such dynamic environments, software systems must adapt to these changes, which has led to the research area of Self-Adaptive Systems (SAS). Platooning is one example of adaptive systems in Intelligent Transportation Systems, which is the ability of vehicles to travel with close inter-vehicle distances. This technology leads to an increase in road throughput and safety, which directly addresses the increased infrastructure needs due to increased traffic on the roads. However, the No-Free-Lunch theorem states that the performance of one adaptation planning strategy is not necessarily transferable to other problems. Moreover, especially in the field of SAS, the selection of the most appropriate strategy depends on the current situation of the system. In this paper, we address the problem of self-aware optimization of adaptation planning strategies by designing a framework that includes situation detection, strategy selection, and parameter optimization of the selected strategies. We apply our approach on the case study platooning coordination and evaluate the performance of the proposed framework.}, author = {Lesch, Veronika and Hadry, Marius and Kounev, Samuel and Krupitzer, Christian}, journal = {ACM Transactions on Autonomous and Adaptive Systems}, keywords = {myown}, month = {oct}, title = {Self-Aware Optimization of Adaptation Planning Strategies}, year = 2022 }
CLIP knows image aesthetics Hentschel, Simon; Kobs, Konstantin; Hotho, Andreas in Frontiers in artificial intelligence (2022). 5 976235.
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Most Image Aesthetic Assessment (IAA) methods use a pretrained ImageNet classification model as a base to fine-tune. We hypothesize that content classification is not an optimal pretraining task for IAA, since the task discourages the extraction of features that are useful for IAA, e.g., composition, lighting, or style. On the other hand, we argue that the Contrastive Language-Image Pretraining (CLIP) model is a better base for IAA models, since it has been trained using natural language supervision. Due to the rich nature of language, CLIP needs to learn a broad range of image features that correlate with sentences describing the image content, composition, environments, and even subjective feelings about the image. While it has been shown that CLIP extracts features useful for content classification tasks, its suitability for tasks that require the extraction of style-based features like IAA has not yet been shown. We test our hypothesis by conducting a three-step study, investigating the usefulness of features extracted by CLIP compared to features obtained from the last layer of a comparable ImageNet classification model. In each step, we get more computationally expensive. First, we engineer natural language prompts that let CLIP assess an image's aesthetic without adjusting any weights in the model. To overcome the challenge that CLIP's prompting only is applicable to classification tasks, we propose a simple but effective strategy to convert multiple prompts to a continuous scalar as required when predicting an image's mean aesthetic score. Second, we train a linear regression on the AVA dataset using image features obtained by CLIP's image encoder. The resulting model outperforms a linear regression trained on features from an ImageNet classification model. It also shows competitive performance with fully fine-tuned networks based on ImageNet, while only training a single layer. Finally, by fine-tuning CLIP's image encoder on the AVA dataset, we show that CLIP only needs a fraction of training epochs to converge, while also performing better than a fine-tuned ImageNet model. Overall, our experiments suggest that CLIP is better suited as a base model for IAA methods than ImageNet pretrained networks.

@article{PMID:36504688, abstract = {Most Image Aesthetic Assessment (IAA) methods use a pretrained ImageNet classification model as a base to fine-tune. We hypothesize that content classification is not an optimal pretraining task for IAA, since the task discourages the extraction of features that are useful for IAA, e.g., composition, lighting, or style. On the other hand, we argue that the Contrastive Language-Image Pretraining (CLIP) model is a better base for IAA models, since it has been trained using natural language supervision. Due to the rich nature of language, CLIP needs to learn a broad range of image features that correlate with sentences describing the image content, composition, environments, and even subjective feelings about the image. While it has been shown that CLIP extracts features useful for content classification tasks, its suitability for tasks that require the extraction of style-based features like IAA has not yet been shown. We test our hypothesis by conducting a three-step study, investigating the usefulness of features extracted by CLIP compared to features obtained from the last layer of a comparable ImageNet classification model. In each step, we get more computationally expensive. First, we engineer natural language prompts that let CLIP assess an image's aesthetic without adjusting any weights in the model. To overcome the challenge that CLIP's prompting only is applicable to classification tasks, we propose a simple but effective strategy to convert multiple prompts to a continuous scalar as required when predicting an image's mean aesthetic score. Second, we train a linear regression on the AVA dataset using image features obtained by CLIP's image encoder. The resulting model outperforms a linear regression trained on features from an ImageNet classification model. It also shows competitive performance with fully fine-tuned networks based on ImageNet, while only training a single layer. Finally, by fine-tuning CLIP's image encoder on the AVA dataset, we show that CLIP only needs a fraction of training epochs to converge, while also performing better than a fine-tuned ImageNet model. Overall, our experiments suggest that CLIP is better suited as a base model for IAA methods than ImageNet pretrained networks.}, author = {Hentschel, Simon and Kobs, Konstantin and Hotho, Andreas}, journal = {Frontiers in artificial intelligence}, keywords = {myown}, pages = 976235, title = {CLIP knows image aesthetics}, volume = 5, year = 2022 }
Resize Me! Exploring the user experience of embodied realistic modulatable avatars for body image intervention in virtual reality D{\"o}llinger, Nina; Wolf, Erik; Mal, David; Wenninger, Stephan; Botsch, Mario; Latoschik, Marc Erich; Wienrich, Carolin in Frontiers in Virtual Reality (2022). 3
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Obesity is a serious disease that can affect both physical and psychological well-being. Due to weight stigmatization, many affected individuals suffer from body image disturbances whereby they perceive their body in a distorted way, evaluate it negatively, or neglect it. Beyond established interventions such as mirror exposure, recent advancements aim to complement body image treatments by the embodiment of visually altered virtual bodies in virtual reality (VR). We present a high-fidelity prototype of an advanced VR system that allows users to embody a rapidly generated personalized, photorealistic avatar and to realistically modulate its body weight in real-time within a carefully designed virtual environment. In a formative multi-method approach, a total of 12 participants rated the general user experience (UX) of our system during body scan and VR experience using semi-structured qualitative interviews and multiple quantitative UX measures. Using body weight modification tasks, we further compared three different interaction methods for real-time body weight modification and measured our system's impact on the body image relevant measures body awareness and body weight perception. From the feedback received, demonstrating an already solid UX of our overall system and providing constructive input for further improvement, we derived a set of design guidelines to guide future development and evaluation processes of systems supporting body image interventions.

@article{dollinger:2022a, abstract = {Obesity is a serious disease that can affect both physical and psychological well-being. Due to weight stigmatization, many affected individuals suffer from body image disturbances whereby they perceive their body in a distorted way, evaluate it negatively, or neglect it. Beyond established interventions such as mirror exposure, recent advancements aim to complement body image treatments by the embodiment of visually altered virtual bodies in virtual reality (VR). We present a high-fidelity prototype of an advanced VR system that allows users to embody a rapidly generated personalized, photorealistic avatar and to realistically modulate its body weight in real-time within a carefully designed virtual environment. In a formative multi-method approach, a total of 12 participants rated the general user experience (UX) of our system during body scan and VR experience using semi-structured qualitative interviews and multiple quantitative UX measures. Using body weight modification tasks, we further compared three different interaction methods for real-time body weight modification and measured our system's impact on the body image relevant measures body awareness and body weight perception. From the feedback received, demonstrating an already solid UX of our overall system and providing constructive input for further improvement, we derived a set of design guidelines to guide future development and evaluation processes of systems supporting body image interventions.}, author = {D{\"o}llinger, Nina and Wolf, Erik and Mal, David and Wenninger, Stephan and Botsch, Mario and Latoschik, Marc Erich and Wienrich, Carolin}, journal = {Frontiers in Virtual Reality}, keywords = {myown}, title = {Resize Me! Exploring the user experience of embodied realistic modulatable avatars for body image intervention in virtual reality}, volume = 3, year = 2022 }
FADE: Towards Flexible and Adaptive Distance Estimation Considering Obstacles Hadry, Marius; Lesch, Veronika; Kounev, Samuel in Companion of the 13th ACM/SPEC International Conference on Performance Engineering (ICPE 2022) (2022).
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@inproceedings{hadry2022towards, author = {Hadry, Marius and Lesch, Veronika and Kounev, Samuel}, booktitle = {Companion of the 13th ACM/SPEC International Conference on Performance Engineering (ICPE 2022)}, keywords = {cyber-physical_systems}, month = {April}, publisher = {ACM}, title = {FADE: Towards Flexible and Adaptive Distance Estimation Considering Obstacles}, year = 2022 }
Why Is It Not Solved Yet? Challenges for Production-Ready Autoscaling Straesser, Martin; Grohmann, Johannes; von Kistowski, J\’{o}akim; Eismann, Simon; Bauer, Andr\’{e}; Kounev, Samuel in Proceedings of the 2022 ACM/SPEC on International Conference on Performance Engineering, ICPE ’22 (2022). 105–115.
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Autoscaling is a task of major importance in the cloud computing domain as it directly affects both operating costs and customer experience. Although there has been active research in this area for over ten years now, there is still a significant gap between the proposed methods in the literature and the deployed autoscalers in practice. Hence, many research autoscalers do not find their way into production deployments. This paper describes six core challenges that arise in production systems that are still not solved by most research autoscalers. We illustrate these problems through experiments in a realistic cloud environment with a real-world multi-service business application and show that commonly used autoscalers have various shortcomings. In addition, we analyze the behavior of overloaded services and show that these can be problematic for existing autoscalers. Generally, we analyze that these challenges are only insufficiently addressed in the literature and conclude that future scaling approaches should focus on the needs of production systems.

@inproceedings{10.1145/3489525.3511680, abstract = {Autoscaling is a task of major importance in the cloud computing domain as it directly affects both operating costs and customer experience. Although there has been active research in this area for over ten years now, there is still a significant gap between the proposed methods in the literature and the deployed autoscalers in practice. Hence, many research autoscalers do not find their way into production deployments. This paper describes six core challenges that arise in production systems that are still not solved by most research autoscalers. We illustrate these problems through experiments in a realistic cloud environment with a real-world multi-service business application and show that commonly used autoscalers have various shortcomings. In addition, we analyze the behavior of overloaded services and show that these can be problematic for existing autoscalers. Generally, we analyze that these challenges are only insufficiently addressed in the literature and conclude that future scaling approaches should focus on the needs of production systems.}, address = {New York, NY, USA}, author = {Straesser, Martin and Grohmann, Johannes and von Kistowski, J\'{o}akim and Eismann, Simon and Bauer, Andr\'{e} and Kounev, Samuel}, booktitle = {Proceedings of the 2022 ACM/SPEC on International Conference on Performance Engineering}, keywords = {myown}, pages = {105–115}, publisher = {Association for Computing Machinery}, series = {ICPE '22}, title = {Why Is It Not Solved Yet? Challenges for Production-Ready Autoscaling}, year = 2022 }
Discrete-Time Analysis of Multi-Component Queuing Networks under Renewal Approximation Geißler, Stefan; Lange, Stanislav; Haßllinger, Gerhard; Tran-Gia, Phuoc; Hoßfeld, Tobias in 34st International Teletraffic Congress (ITC). , Shenzhen, China (2022).
- [ Abstract ]
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The analytical and numerical performance evaluation of network components and distributed systems has been a staple in the networking community for many years. However, the ever growing complexity of modern systems and the need to gain detailed insights into systems consisting of many, interconnected components emphasizes the need for an extension to the classical single-component approach, and although approaches like Jackson Networks exist, their limited application scope lags behind the complexity of modern environments. To this end, we revisit existing models of the common Gi/Gi/1-oo queue, extend them to allow the concatenation of multiple queueing components, and evaluate the approximation error introduced through renewal approximation. We revisit previously performed parameter studies and evaluate the approximation error for a wide range of parameter combinations that we can solve through the power of modern computing equipment and efficient numerical implementations of our models. We show the main impact factors for the linear concatenation of queueing components as well as the split and superposition of processes. Our evaluations show that the renewal approximation can be applied to a wide range of parameters while still obtaining results within acceptable error margins.

@inproceedings{info3-inproceedings-2022-17, abstract = {The analytical and numerical performance evaluation of network components and distributed systems has been a staple in the networking community for many years. However, the ever growing complexity of modern systems and the need to gain detailed insights into systems consisting of many, interconnected components emphasizes the need for an extension to the classical single-component approach, and although approaches like Jackson Networks exist, their limited application scope lags behind the complexity of modern environments. To this end, we revisit existing models of the common Gi/Gi/1-oo queue, extend them to allow the concatenation of multiple queueing components, and evaluate the approximation error introduced through renewal approximation. We revisit previously performed parameter studies and evaluate the approximation error for a wide range of parameter combinations that we can solve through the power of modern computing equipment and efficient numerical implementations of our models. We show the main impact factors for the linear concatenation of queueing components as well as the split and superposition of processes. Our evaluations show that the renewal approximation can be applied to a wide range of parameters while still obtaining results within acceptable error margins.}, author = {Geißler, Stefan and Lange, Stanislav and Haßllinger, Gerhard and Tran-Gia, Phuoc and Hoßfeld, Tobias}, booktitle = {34st International Teletraffic Congress (ITC). , Shenzhen, China}, keywords = {can}, month = 9, title = {Discrete-Time Analysis of Multi-Component Queuing Networks under Renewal Approximation}, year = 2022 }
Usability and User Experience of Virtual Objects Supporting Learning and Communicating in Virtual Reality Hein, Rebecca; Latoschik, Marc Erich; Wienrich, Carolin in Mensch und Computer 2022 - Tagungsband, B. Pfleging, K. Gerling, S. Mayer (eds.) (2022). 510–514.
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This study aims to evaluate the usability and user experience of the InteractionSuitecase. This is a collection of virtual objects that have cultural connotations (associated with German or Anglo-American culture). They are intended to promote communication about cultural differences and similarities in English lessons at German schools. They are thus part of a didactic concept for using social VR for trans- and intercultural learning. Future teacher used the virtual objects during a practical seminar and rated them as useful. Further they associates a positive user experience. Since the virtual objects should encourage communication, the sense of connectedness instead of isolation is a very important results. The results proved the readiness of the InteractionSuitcase for further pedagogical applications.

@inproceedings{mci/Hein2022, abstract = {This study aims to evaluate the usability and user experience of the InteractionSuitecase. This is a collection of virtual objects that have cultural connotations (associated with German or Anglo-American culture). They are intended to promote communication about cultural differences and similarities in English lessons at German schools. They are thus part of a didactic concept for using social VR for trans- and intercultural learning. Future teacher used the virtual objects during a practical seminar and rated them as useful. Further they associates a positive user experience. Since the virtual objects should encourage communication, the sense of connectedness instead of isolation is a very important results. The results proved the readiness of the InteractionSuitcase for further pedagogical applications.}, address = {New York}, author = {Hein, Rebecca and Latoschik, Marc Erich and Wienrich, Carolin}, booktitle = {Mensch und Computer 2022 - Tagungsband}, editor = {Pfleging, Bastian and Gerling, Kathrin and Mayer, Sven}, keywords = {rhein}, pages = {510-514}, publisher = {ACM}, title = {Usability and User Experience of Virtual Objects Supporting Learning and Communicating in Virtual Reality}, year = 2022 }
Digitale Leseförderung: Effekte eines silbenbasierten digitalen Lesetrainings in Klasse 2 Heß, J.; Karageorgos, P.; Richter, T.; Müller, B.; Riedmann, A.; Schaper, P.; Lugrin, B. in Vortrag auf dem 52. Kongress der Deutschen Gesellschaft für Psychologie (DGPs) (2022).
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@conference{hess2022digitale, author = {Heß, J. and Karageorgos, P. and Richter, T. and Müller, B. and Riedmann, A. and Schaper, P. and Lugrin, B.}, booktitle = {Vortrag auf dem 52. Kongress der Deutschen Gesellschaft für Psychologie (DGPs)}, keywords = {schaper}, title = {Digitale Leseförderung: Effekte eines silbenbasierten digitalen Lesetrainings in Klasse 2}, year = 2022 }
Automated Triage of Performance Change Points Using Time Series Analysis and Machine Learning Bauer, André; Straesser, Martin; Beierlieb, Lukas; Meissner, Maximilian; Kounev, Samuel in Proceedings of the 2022 ACM/SPEC on International Conference on Performance Engineering (2022).
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@conference{bauer2022automated, author = {Bauer, André and Straesser, Martin and Beierlieb, Lukas and Meissner, Maximilian and Kounev, Samuel}, booktitle = {Proceedings of the 2022 ACM/SPEC on International Conference on Performance Engineering}, keywords = {timeseries}, month = 4, publisher = {ACM}, title = {Automated Triage of Performance Change Points Using Time Series Analysis and Machine Learning}, year = 2022 }