1.
Tran, H.T., Pham Ngoc, N., Hoßfeld, T., Seufert, M., Thang, T.C.: Cumulative Quality Modeling for HTTP Adaptive Streaming. ACM Transactions on Multimedia Computing, Communications, and Applications. 17, 22 (1–24) (2021).
2.
Heß, J., Karageorgos, P., Richter, T., Müller, B., Riedmann, A., Schaper, P., Lugrin, B.: Digitale Leseförderung: Konzeption und Evaluation der "Mobilen Leseförderung". Round Table-Session präsentiert auf der Online-Tagung der Fachgruppe Pädagogische Psychologie der Deutschen Gesellschaft für Psychologie (DGPs) (2021).
3.
Kern, F., Keser, T., Niebling, F., Latoschik, M.E.: Using Hand Tracking and Voice Commands to Physically Align Virtual Surfaces in AR for Handwriting and Sketching with HoloLens 2. 27th ACM Symposium on Virtual Reality Software and Technology. S. 1–3. Association for Computing Machinery, Osaka, Japan (2021).
In this paper, we adapt an existing VR framework for handwriting and sketching on physically aligned virtual surfaces to AR environments using the Microsoft HoloLens 2. We demonstrate a multimodal input metaphor to control the framework’s calibration features using hand tracking and voice commands. Our technical evaluation of fingertip/surface accuracy and precision on physical tables and walls is in line with existing measurements on comparable hardware, albeit considerably lower compared to previous work using controller-based VR devices. We discuss design considerations and the benefits of our unified input metaphor suitable for controller tracking and hand tracking systems. We encourage extensions and replication by providing a publicly available reference implementation (https://go.uniwue.de/hci-otss-hololens).
4.
Lugrin, B., Pelachaud, C., Traum, D.: The Handbook on Socially Interactive Agents – 20 Years of Research on Embodied Conversational Agents, Intelligent Virtual Agents, and Social Robotics, Volume 1: Methods, Behavior, Cognition. ACM (2021).
5.
Weber, D., Hertweck, S., Alwanni, H., Fiederer, L.D.J., Wang, X., Unruh, F., Fischbach, M., Latoschik, M.E., Ball, T.: A Structured Approach to Test the Signal Quality of Electroencephalography Measurements During Use of Head-Mounted Displays for Virtual Reality Applications. Frontiers in Neuroscience. 15, 1527 (2021).
Joint applications of virtual reality (VR) systems and electroencephalography (EEG) offer numerous new possibilities ranging from behavioral science to therapy. VR systems allow for highly controlled experimental environments, while EEG offers a non-invasive window to brain activity with a millisecond-ranged temporal resolution. However, EEG measurements are highly susceptible to electromagnetic (EM) noise and the influence of EM noise of head-mounted-displays (HMDs) on EEG signal quality has not been conclusively investigated. In this paper, we propose a structured approach to test HMDs for EM noise potentially harmful to EEG measures. The approach verifies the impact of HMDs on the frequency- and time-domain of the EEG signal recorded in healthy subjects. The verification task includes a comparison of conditions with and without an HMD during (i) an eyes-open vs. eyes-closed task, and (ii) with respect to the sensory- evoked brain activity. The approach is developed and tested to derive potential effects of two commercial HMDs, the Oculus Rift and the HTC Vive Pro, on the quality of 64-channel EEG measurements. The results show that the HMDs consistently introduce artifacts, especially at the line hum of 50 Hz and the HMD refresh rate of 90 Hz, respectively, and their harmonics. The frequency range that is typically most important in non-invasive EEG research and applications (<50 Hz) however, remained largely unaffected. Hence, our findings demonstrate that high-quality EEG recordings, at least in the frequency range up to 50 Hz, can be obtained with the two tested HMDs. However, the number of commercially available HMDs is constantly rising. We strongly suggest to thoroughly test such devices upfront since each HMD will most likely have its own EM footprint and this article provides a structured approach to implement such tests with arbitrary devices.
6.
Supervisor: Poignée, F.: Simulating Group-based Communication with Omnet++, (2021).
7.
Seufert, C., Oberdörfer, S., Roth, A., Grafe, S., Lugrin, J.-L., Latoschik, M.E.: Classroom management competency enhancement for student teachers using a fully immersive virtual classroom. Computers & Education. 104410 (2021).
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 XXX 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 ProjectName 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.
8.
Bühler, M.: Modelling the Communication behavior in WhatsApp, (2021).
9.
Raffeck, S.: Evaluating the Nature-inspired DESYNC Mechanism as an Energy-efficient LoRaWAN MAC, (2021).
10.
Lugrin, B., Rehm, M.: Culture for Socially Interactive Agents. In: Lugrin, B., Pelachaud, C., und Traum, D. (hrsg.) The Handbook on Socially Interactive Agents – 20 Years of Research on Embodied Conversational Agents, Intelligent Virtual Agents, and Social Robotics, Volume 1: Methods, Behavior, Cognition. S. 463–494. ACM (2021).
11.
Davidson, P., Buckermann, F., Steininger, M., Krause, A., Hotho, A.: Semi-unsupervised Learning: An In-depth Parameter Analysis. In: Edelkamp, S., Möller, R., und Rueckert, E. (hrsg.) KI 2021: Advances in Artificial Intelligence. S. 51–66. Springer International Publishing, Cham (2021).
Creating datasets for supervised learning is a very challenging and expensive task, in which each input example has to be annotated with its expected output (e.g. object class). By combining unsupervised and semi-supervised learning, semi-unsupervised learning proposes a new paradigm for partially labeled datasets with additional unknown classes. In this paper we focus on a better understanding of this new learning paradigm and analyze the impact of the amount of labeled data, the number of augmented classes and the selection of hidden classes on the quality of prediction. Especially the number of augmented classes highly influences classification accuracy, which needs tuning for each dataset, since too few and too many augmented classes are detrimental to classifier performance. We also show that we can improve results on a large variety of datasets when using convolutional networks as feature extractors while applying output driven entropy regularization instead of a simple weight based L2 norm.
12.
Supervisor: Dietz, K.: Incorporation of Active Learning Mechanisms into Machine Learning Approaches for Network Management, (2021).
While Machine Learning (ML) is gaining more and more popularity, the actual incorporation into running systems is still lacking, e.g., due to missing trust of network operators. To build this trust, the goal of this work is to incorporate an active learning approach into an already existing ML-approach, that opens up the possibility of making ML-based decisions more explainable and allows to incorporate feedback of the administrator, e.g.,to retrain ML models with the adjusted decisions.
13.
Supervisor: Seufert, A.: Crowdsourced Coverage Hole Detection for Mobile Networks, (2021).
Contact: anika.seufert@informatik.uni-wuerzburg.de
14.
Foerster, K., Hein, R., Grafe, S., Latoschik, M.E., Wienrich, C.: Fostering Intercultural Competencies in Initial Teacher Education. Implementation of Educational Design Prototypes using a Social VR Environment. In: Bastiaens, T. (hrsg.) Proceedings of Innovate Learning Summit 2020 2021. S. 73–86. Association for the Advancement of Computing in Education (AACE), Online, United States (2021).
The combination of globalization and digitalization emphasizes the importance of media-related and intercultural competencies of teacher educators and pre-service teachers. This article reports on the initial prototypical implementation of a pedagogical concept to foster such competencies of pre-service teachers. The proposed pedagogical concept utilizes a social VR framework since related work on the characteristics of VR indicate that this medium is particularly well suited for intercultural professional development processes. The development is integrated into a larger design-based-research approach that develops a theory-guided and empirically grounded professional development concept for teacher educators with a special focus on TETC 8. TETC provide a suitable competence framework capable of aligning both requirements for media-related as well as intercultural competencies. In an exploratory study with student teachers we designed...
15.
Schröter, T., Tiede, J., Grafe, S., Latoschik, M.E.: Fostering Teacher Educator Technology Competencies (TETCs) in and with Virtual Reality. Results from an Exploratory Study. In: Bastiaens, T. (hrsg.) Proceedings of Innovate Learning Summit 2021. S. 160–170. Association for the Advancement of Computing in Education (AACE), Online, United States (2021).
This exploratory study presents the findings and implications of a three-hour further development workshop implemented with a convenience sample of six teacher educators from a German university. The workshop aimed at fostering the Teacher Educator Technology Competencies (TETCs)—with a special focus on virtual reality (VR)—while reverting to the didactic principle of action orientation. To test whether this didactic principle is suitable for fostering the media pedagogical competencies of the target group in and with VR and to identify further design principles, a mixed-methods approach was utilized. The data collection consisted of focus group interviews, which were analyzed via qualitative content analysis, and Teacher Educator Technology Surveys (TETS). The analysis revealed that action orientation is a valuable addition to established didactical models in higher education (HE). Also...
16.
Schröter, T., Tiede, J., Latoschik, M.E.: Fostering Teacher Educator Technology Competencies (TETCs) in and with Virtual Reality. A Case Study. In: Bastiaens, T. (hrsg.) Proceedings of EdMedia + Innovate Learning. S. 617–629. Association for the Advancement of Computing in Education (AACE) (2021).
17.
Supervisor: Wehner, N.: Towards a Low Latency QoE Fair HAS Logic, (2021).
Contact: nikolas.wehner@uni-wuerzburg.de Abstract: Nowadays, basically all videos are streamed via HTTP Adaptive Streaming (HAS). An important concept in terms of HAS is the Quality of Experience (QoE), which describes how users perceive video streaming. QoE fairness extends the concept of QoE by comparing the QoE of mutliple clients in a shared network. An important component influencing the QoE and consequently the QoE fairness is the HAS adaptation logic, which is responsible for downloading the segments with the goal to obtain the best possible video quality without causing stalling, i.e., playback interruption due to buffer underrun. The goal of this work is to implement an adaptation logic, currently implemented in a simulation, into a real video player and evaluating the QoE and QoE fairness of the adaptation logic when confronted with low-latency situations in real scenarios.
18.
Truman, S., Seitz, J., von Mammen, S.: Stigmergic, Diegetic Guidance of Swarm Construction. International Conference on Soft Computing Models in Industrial and Environmental Applications. (2021).
19.
Fernes, D., Oberdörfer, S., Latoschik, M.E.: Recreating a Medieval Mill as a Virtual Learning Environment. 27th ACM Symposium on Virtual Reality Software and Technology (VRST ’21). ACM, Osaka, Japan (2021).
20.
Keppler, S., Döllinger, N., Wienrich, C., Latoschik, M.E., Israel, J.H.: Self-Touch: An Immersive Interaction-Technique to Enhance Body Awareness. Gehalten auf der (2021).
21.
Büttner, J., von Mammen, S.: Training a Reinforcement Learning Agent based on XCS in a Competitive Snake Environment. IEEE COG 2021. 2021, (2021).
22.
Wehner, N., Seufert, M., Schüler, J., Casas, P., Hoßfeld, T.: How are your Apps Doing? QoE Inference and Analysis in Mobile Devices. 17th International Conference on Network and Service Management (CNSM). , Izmir, Turkey (Virtual Conference) (2021).
Web browsing has become the most important application of the Internet for the end user. When it comes to mobile devices, web services are mainly accessed through apps. This paper tackles the problem of Web Quality of Experience (QoE) in mobile devices, with a specific focus on apps QoE monitoring and analysis, using in-network (encrypted) traffic measurements. Measuring apps QoE is complex, not only from an instrumentation point of view, but also from the heterogeneity of user interactions which might realize substantially different user experience. To this end, we conduct a feasibility study on four specific and popular Android apps and their corresponding web services. Our test automation framework emulates and measures different user interactions commonly executed during an app session, including the app startup, clicking, scrolling, and searching. The resulting traffic is characterized on different dimensions, and machine learning models are trained to identify web services, apps, and user interactions, and to infer their QoE. The proposed models can correctly identify the specific web service and app in 86% of the cases and accurately estimate the associated QoE with small errors. Our preliminary study represents a first step towards an in-network, web QoE monitoring solution for mobile-device apps.
23.
Arslanian, A.: QoE Study for Compatible Video and Web Browsing QoE Models, (2021).
24.
Supervisor: Grigorjew, A.: Investigation of Hardware and Software Timestamping in Different Network Interfaces, (2021).
Kontakt: <alexej.grigorjew@uni-wuerzburg.de> - Ziel: Vergleich unterschiedlicher Mechanismen zum Timestamping von eingehenden (und ggf. ausgehenden) Paketen mit unterschiedlichen Netzwerkkarten und Endgeräten; Betrachtung von Genauigkeiten, Unterschieden, Konsistenz, Voraussetzungen und Aufwand
25.
BenSiSaid, K., Ababou, N., Ababou, A., Roth, D., von Mammen, S.: Tracking rower motion without on-body sensors using an instrumented machine and an artificial neural network. Proceedings of the Institution of Mechanical Engineers, Part P: Journal of Sports Engineering and Technology. (2021).
26.
Schreiner, L., von Mammen, S.: Modding Support of Game Engines. The 16th International Conference on the Foundations of Digital Games (FDG) 2021. Association for Computing Machinery, Montreal, QC, Canada (2021).
This paper aims at showing how different game engines support modding. To this end, the concepts of modding and game engines alongside their historical evolution are introduced first. Additionally, some well-known game engines and mods are presented, and their unique features are described. Further, the effects of using game engines and those that modding has on games, developers, and players are laid out. Particular focus is placed on the effects on competitive games. These effects include an enhanced lifespan for games and the requirement for more development effort. Finally, the modding-support of selected game engines is illustrated and compared with each other. These engines are the id Tech engine(s), Unreal Engine, the Source engine, and Unity. The paper is then concluded with an outlook on future research possibilities and recommendations to developers.
27.
Truman, S., von Mammen, S.: Interactive Self-Assembling Agent Ensembles. Proceedings of the 1st Games Technology Summit. (2021).
28.
Mußmann, M., Truman, S., von Mammen, S.: Game-Ready Inventory Systems for Virtual Reality. IEEE COG 2021. 2021, (2021).
29.
Pham, T.T.: Quantifying the Influence of Consent Banners on Web QoE with Crowdsourcing, (2021).
Contact: nikolas.wehner@uni-wuerzburg.de Abstract: Quality of Experience (QoE) is a concept introduced to describe the delight or frustration with a networked service. Web browsing is one of the most dominant applications in the Internet today and it could be observed that especially waiting times are the crucial influence factor when it comes to quantifying Web QoE. However, due to the increased interest in data privacy, websites nowadays have to adopt consent banners, which are shown immediately on startup. These consent banners often take different shapes, e.g., in form of pop-up windows or additional bars on the website, and sometimes effectively block the actual content of a page. The influence of such consent banners on the Web QoE is not well understood yet. Goal of this work is thus to design, implement, and conduct a QoE study which investigates the influence of consent banners on Web QoE.
30.
Tritscher, J., Krause, A., Schlör, D., Gwinner, F., von Mammen, S., Hotho, A.: A financial game with opportunities for fraud. IEE COG 2021. 2021, (2021).
Even though companies store large amounts of business data in enterprise resource planning (ERP) systems, obtaining data for financial fraud detection is prohibitively difficult due to privacy concerns and companies protecting trade secrets. One possible solution is game-based generation of synthetic ERP data, which poses the challenge of designing an environment that generates realistic ERP data and allows players to commit many different types of fraud. In this work, we design a multiplayer game that allows players to cooperatively run a fictional company, while simultaneously challenging them to maximize their personal gain. We introduce an approach for letting players explore fraud scenarios through emergent gameplay and present a prototype that may be primed with information from real world ERP systems to generate realistic data.
31.
Supervisor: Dietz, K.: Evaluation of Topology Synthetization Approaches for Communication Networks, (2021).
With the recent rise in popularity of Machine Learning (ML), the quest for data acquisition is more relevant than ever. When investigating communication networks on a large scale, though, gaining data from a wide variety of networks is difficult, as access is often limited. Simulation-based approaches are leveraged to circumvent this problem. Even then, however, one needs to model appropriate network topologies, that reflect real-world properties. One source of such information is the Internet Topology Zoo, containing over 250 different Wide Area Networks (WANs) throughout the world. Though, in terms of quantity, this amount of data is often still insufficient for ML-based approaches. Many algorithms for generating networks exist, but rather than being applicable for communication networks, these models usually aim to reflect characteristics of social networks. Thus, one recently emerging method of synthesizing artificial data are Generative Adversarial Networks (GANs), a deep-learning based approach for data generation. The goal of this work is to explore GANs and other sophisticated network generators to synthetize networks, that reflect topological characteristics of real-world WANs.
32.
Kern, F., Popp, M., Kullmann, P., Ganal, E., Latoschik, M.E.: 3D Printing an Accessory Dock for XR Controllers and its Exemplary Use as XR Stylus. 27th ACM Symposium on Virtual Reality Software and Technology. S. 1–3. Association for Computing Machinery, Osaka, Japan (2021).
This article introduces the accessory dock, a 3D printed multipurpose extension for consumer-grade XR controllers that enables flexible mounting of self-made and commercial accessories. The uniform design of our concept opens new opportunities for XR systems being used for more diverse purposes, e.g., researchers and practitioners could use and compare arbitrary XR controllers within their experiments while ensuring access to buttons and battery housing. As a first example, we present a stylus tip accessory to build an XR Stylus, which can be directly used with frameworks for handwriting, sketching, and UI interaction on physically aligned virtual surfaces. For new XR controllers, we provide instructions on how to adjust the accessory dock to the controller’s form factor. A video tutorial for the construction and the source files for 3D printing are publicly available for reuse, replication, and extension (https://go.uniwue.de/hci-otss-accessory-dock).
33.
Supervisor: Metzger, F.: Desktop-wide Raw APM Measurements, (2021).
Actions per minute are an important metric in understanding the tempo of interactive applications and games. And tempo provides context for subjective quality assessments of these apps. Your task would be to create a software tool which captures all input events on a desktop operating system and use that tool to perform a study of the APM characteristics of several different interactive applications.
34.
Supervisor: Metzger, F.: Exploring the Latency of 802.11 DCF, PCF and HCF, (2021).
The distributed channel access coordination function of 802.11 can be problematic when one desires consistency in the channel access delay, or even bounded delay. PCF, EDCA and HCCA aim to partially remedy this situation, but it is unclear how much of an actual improvement they can provide and how well they work in practical situations. In this work your task would be to first get a good understanding of the state of the art of 802.11 channel access coordination, and using this, create a comparative study of the concrete effects of the individual mechanisms.
35.
Qi, Y., Bruch, D., Krop, P., Herrmann, M.J., Latoschik, M.E., Deckert, J., Hein, G.: Social buffering of human fear is shaped by gender, social concern and the presence of real vs virtual agents. (2021).
The presence of a partner can attenuate physiological fear responses, a phenomenon known as social buffering. However, not all individuals are equally sociable. Here we investigated whether social buffering of fear is shaped by sensitivity to social anxiety (social concern) and whether these effects are different in females and males. We collected skin conductance responses (SCRs) and affect ratings of female and male participants when they experienced aversive and neutral sounds alone (alone treatment) or in the presence of an unknown person of the same gender (social treatment). Individual differences in social concern were assessed based on a well-established questionnaire. Our results showed that social concern had a stronger effect on social buffering in females than in males. The lower females scored on social concern, the stronger the SCRs reduction in the social compared to the alone treatment. The effect of social concern on social buffering of fear in females disappeared if participants were paired with a virtual agent instead of a real person. Together, these results showed that social buffering of human fear is shaped by gender and social concern. In females, the presence of virtual agents can buffer fear, irrespective of individual differences in social concern. These findings specify factors that shape the social modulation of human fear, and thus might be relevant for the treatment of anxiety disorders.
36.
Wienrich, C., Komma, P., Vogt, S., Latoschik, M.E.: Spatial Presence in Mixed Realities--Considerations about the Concept, Measures, Design, and Experiments. Frontiers in Virtual Reality. 2, 141 (2021).
Plenty of theories, models, measures, and investigations target the understanding of virtual presence, i.e., the sense of presence in immersive Virtual Reality (VR). Other varieties of the so-called eXtended Realities (XR), e.g., Augmented and Mixed Reality (AR and MR) incorporate immersive features to a lesser degree and continuously combine spatial cues from the real physical space and the simulated virtual space. This blurred separation questions the applicability of the accumulated knowledge about the similarities of virtual presence and presence occurring in other varieties of XR, and corresponding outcomes. The present work bridges this gap by analyzing the construct of presence in mixed realities (MR). To achieve this, the following presents (1) a short review of definitions, dimensions, and measurements of presence in VR, and (2) the state of the art views on MR. Additionally, we (3) derived a working definition of MR, extending the Milgram continuum. This definition is based on entities reaching from real to virtual manifestations at one time point. Entities possess different degrees of referential power, determining the selection of the frame of reference. Furthermore, we (4) identified three research desiderata, including research questions about the frame of reference, the corresponding dimension of transportation, and the dimension of realism in MR. Mainly the relationship between the main aspects of virtual presence of immersive VR, i.e., the place-illusion, and the plausibility-illusion, and of the referential power of MR entities are discussed regarding the concept, measures, and design of presence in MR. Finally, (5) we suggested an experimental setup to reveal the research heuristic behind experiments investigating presence in MR. The present work contributes to the theories and the meaning of and approaches to simulate and measure presence in MR. We hypothesize that research about essential underlying factors determining user experience (UX) in MR simulations and experiences is still in its infancy and hopes this article provides an encouraging starting point to tackle related questions.
37.
Chaplick, S., Kindermann, P., Klawitter, J., Rutter, I., Wolff, A.: Extending Partial Representations of Rectangular Duals with Given Contact Orientations. In: Calamoneri, T. und Coró, F. (hrsg.) Proc. 12th International Conference on Algorithms and Complexity (CIAC’21). S. 340–353. Springer-Verlag (2021).
38.
Knaub, A.: Investigation of Stream Aggregates for Asynchronous Traffic Shaping, (2021).
Kontakt: alexej.grigorjew@uni-wuerzburg.de -- Moderne Systeme enthalten immer mehr Machine-to-Machine (M2M) Kommunikation, welche traditionell durch Bus-Systeme wie CAN und PROFIBUS unterstützt wurden. Neuere Systeme haben jedoch höhere Anforderungen an Bandbreite, Latenz und Zuverlässigkeit, weshalb langsam ein Übergang in Richtung Ethernet-Technologien stattfindet. Daraus entstanden sehr viele verschiedene Technologien, die im Grunde die gleichen Ziele verfolgen, aber untereinander nicht kompatibel sind. Die IEEE Standardisierungsgruppe Time-Sensitive Networking (TSN) versucht, durch diverse Erweiterungen der Ethernet-Standards eine einheitliche Definition der Mechanismen zu bilden. Ein solcher Mechanismus, der Echtzeit-Garantien ermöglicht, lautet Asynchronous Traffic Shaping (ATS). Zur Einhaltung der Garantien sind außerdem Reservierungsprotokolle im Einsatz. Ein neuer Echtzeit-Datenstrom sendet seine Anforderungen an das Netzwerk und wird entweder angenommen oder abgelehnt, je nach vorhandenen Ressourcen. Dabei geht es nicht nur um Bandbreite, sondern z.B. auch um Warteschlangenlängen und Prioritäten. Formeln zur Berechnung der Latenz existieren bereits in der Literatur. Diese sind jedoch von Natur aus ineffizient bei Datenströmen, die sehr selten senden (~ 1 Mal pro Sekunde). Sie verbrauchen ähnlich viele Warteschlangen-Ressourcen wie häufig sendende Ströme (~ 1 Mal pro Millisekunde), benötigen aber natürlich viel weniger Bandbreite. So kann eine Ablehnung schon dann erfolgen, wenn eigentlich kaum Verkehr fließt. Hier soll Stream Aggregation ansetzen. Viele sehr kleine Datenströme werden zu einem größeren Strom mit etwas höherer Bandbreite zusammengefasst, um die Ressourcen effizienter einsetzen zu können. Für ATS auf der Data-Plane erscheint das Aggregat wie ein einziger Strom. In dieser Arbeit soll ein kleines Framework zur Berechnung der Latenzgarantien in einem gegebenen Netzwerk geschrieben werden. Außerdem soll eine Möglichkeit zur Aggregation mehrerer Ströme eingebaut werden. In der Evaluation soll dann dieses Framework benutzt werden, um für einige Netzwerke exemplarisch die Effizienz mit und ohne Aggregation zu vergleichen.
39.
Walter, J., Zink, J., Baumeister, J., Wolff, A.: Layered Drawing of Undirected Graphs with Generalized Port Constraints. In: Auber, D. und Valtr, P. (hrsg.) Proc. 28th Int. Symp. Graph Drawing & Network Vis. (GD’20). S. 220–234. Springer-Verlag (2021).
40.
Supervisor: Seufert, M.: Investigating Quality of Experience of Video Conferencing via Crowdsourcing Study, (2021).
Contact/Kontakt: michael.seufert@uni-wuerzburg.de --- Abstract: A browser-based study for video conferencing shall be implemented, which allows to investigate the influence of different performance factors on the QoE, such as video quality, audio quality, or audio/video synchronisation. A study shall be conducted via crowdsourcing and the results shall be evaluated. --- Inhalt: Es soll eine browserbasierte Studie für Videokonferenzen implementiert werden, die es erlaubt den Einfluss verschiedener Leistungskriterien auf die QoE zu untersuchen, wie z.B. Videoqualität, Audioqualität oder Audio-Video-Synchronisierung. Eine Studie soll via Crowdsourcing durchgeführt werden und die Ergebnisse sollen ausgewertet werden.
41.
Dietz, K., Mühlhauser, M., Seufert, M., Gray, N., Hoßfeld, T., Herrmann, D.: Browser Fingerprinting: How to Protect Machine Learning Models and Data with Differential Privacy?. 1st International Workshop on Machine Learning in Networking (MaLeNe). , Lübeck, Germany (Virtual Conference) (2021).
42.
Pimpinella, A., Redondi, A.E., Loh, F., Seufert, M.: Machine-Learning Based Prediction of Next HTTP Request Arrival Time in Adaptive Video Streaming. 3rd International Workshop on High-Precision, Predictable, and Low-Latency Networking (HiPNet). , Izmir, Turkey (Virtual Conference) (2021).
43.
Bosch, Y., Schäfer, P., Spoerhase, J., Storandt, S., Zink, J.: Consistent Simplification of Polyline Tree Bundles. Proc. 27th International Computing and Combinatorics Conference (COCOON’21) (2021).
44.
Loh, F., Bau, D., Zink, J., Wolff, A., Hoßfeld, T.: Robust Gateway Placement for Scalable LoRaWAN. 13th IFIP Wireless and Mobile Networking Conference (WMNC) (2021).
Many exciting applications are currently emerging due to the use of technology from the Internet of Things (IoT) in Smart Cities. In recent years, Long Range Wide Area Networks (LoRaWANs) have become one of the main technologies in this field due to long distance coverage, low power consumption sensors, and economic reasons. So far, LoRaWANs have been planned and deployed mainly with the aim of minimizing the number of gateways, while still providing coverage in a geographic area. Packet collisions and future traffic have not been considered. In contrast, we present a gateway placement strategy that is robust against an increase in the number of sensors and in the network load. To this end, we modify an existing local search algorithm for a geometric set cover problem such that it takes the capacities of gateways into account. If we set these capacities below the maximum, the network can accommodate additional sensors in the future. Moreover, our algorithm can extend the initial placement once the capacities are exhausted.
45.
Loh, F., Raffeck, S., Metzger, F., Hoßfeld, T.: Improving LoRaWAN’s Successful Information Transmission Rate with Redundancy. 17th International Conference on Wireless and Mobile Computing, Networking and Communications (WiMob) (2021).
The adaptation of Internet of Things in our everyday life shows different new demands and challenges. One of the fastest growing technologies in this context are Low Power Wide Area Networks with LoRaWAN as one of their most prominent representatives. The promise of this technology is to transmit sensor data over large distances with very little energy consumption. But transmission behavior, and especially overhead and collision probability, must be studied in detail to improve transmission quality and energy consumption due to the random access nature of LoRaWAN. Because of that, this work investigates the LoRaWAN channel capacity by analyzing the transmission overhead, the collision probability, and the data loss. At the end, an energy consumption comparison is done. The contribution is a novel approach based on aggregation and retransmission that shows a decreased data loss of up to 20% compared to the currently used random channel access.
46.
Supervisor: Seufert, M.: Design and Comparison of Heuristic- and DL-based Estimators of QoE Factors from Visual Recordings, (2021).
Contact/Kontakt: michael.seufert@uni-wuerzburg.de --- Abstract: A heuristic- and/or deep-learning-based software shall be implemented and evaluated, which allows to detect QoE factors from a visual recording of the client's screen, such as video resolution, frame rate, or stalling. --- Inhalt: Eine auf Heuristiken und/oder Deep Learning basierte Software soll implementiert und evaluiert werden, die es erlaubt QoE Faktoren aus einer Videoaufnahme des Bildschirm des Clients zu erkennen, wie z.B. Videoauflösung, Framerate oder Stalling.
47.
Supervisor: Seufert, M.: Models for Group Communication Behavior under Mobility, (2021).
Contact/Kontakt: michael.seufert@uni-wuerzburg.de --- Abstract: In this work, a literature study shall be conducted to survey existing models for mobility and communication behavior, i.e., how people communicate while they are moving (e.g., walking, riding a bus). Selected models shall be implemented and implications of mobility on communication behavior shall be simulatively derived. --- Inhalt: In dieser Arbeit soll eine Literaturstudie durchgeführt werden, um einen Überblick über existierende Modelle für Mobilität und Kommunikationsverhalten zu erhalten, d.h. wie Menschen kommunizieren während sie unterwegs sind (z.B. laufen oder Bus fahren). Ausgewählte Modelle sollen implementiert werden und die Auswirkungen von Mobilität auf das Kommunikationsverhalten sollen simulativ abgeleitet werden.
48.
Metzger, F., Schröder, S., Ratetseder, A.: Subjective And Objective Assessment Of Video Game Context Factors, (2021).
49.
Hein, R.M., Steinbock, J., Eisenmann, M., Wienrich, C., Latoschik, M.E.: Inter- und Transkulturelles Lernen in Virtual Reality - Ein Seminarkonzept für die Lehrkräfteausbildung im Fach Englisch. In: Söbke, H. & Weise, M. (Hrsg.), Wettbewerbsband AVRiL 2021. 34–39 (2021).
Inter- und transkulturelle Kompetenzen sind zentrale Elemente einer aktiven Teilhabe in einer modernen Gesellschaft. Die Fremdsprachenforschung setzt sich im Kontext der Digitalisierung mit neuen Konzepten zum Erwerb dieser Kompetenzen im Fremdsprachenunterricht auseinander. Eine Zusammenarbeit mit der HCI-Forschung zum Einsatz von social VR im Klassenzimmer lässt auf einen positiven Erkenntnisgewinn schließen. So lautet die zentrale Forschungshypothese, dass vollimmersive Lernumgebungen verstärkt inter- und transkulturelle Lernprozesse fördern, weil Lernende VR-Welten nicht nur betrachten, sondern innerhalb dieser selbstwirksam interagieren und das Umfeld eigenständig manipulieren können. Darauf aufbauend wurde ein Seminarkonzept entwickelt, in dem Lehramtsstudierende für das Fach Englisch inter- und transkulturelle Lehr/Lernszenarien in VR konzipieren, die sie dann in ihrer Unterrichtspraxis einsetzen können. So lernen Studierende das Potenzial von VR nicht nur kennen, sondern ebenso dieses unterrichtlich umzusetzen.
50.
Leidinger, F.: Measuring the Effectiveness of Latency Mitigation Methods with a Prototype Video Game, (2021).
Video games with a competitive multiplayer modes must deal with the troubles of high and varying end-to-end lag. They can employ varying methods to manage, mitigate or conceal this lag and equalize it between different clients. But the closed source nature of video games makes examining the effectiveness of these mechanisms hard. Your job is to implement a simple video game prototype from scratch that uses an authoritative client-server multiplayer approach and implements such lag mitigation mechanisms. With this prototype we want to get a better understanding of the effectiveness of these lag concealment measures.
51.
Münster, S., Maiwald, F., Bruschke, J., Kröber, C., Dietz, R., Messemer, H., Niebling, F.: WHERE ARE WE NOW ON THE ROAD TO 4D URBAN HISTORY RESEARCH AND DISCOVERY?. ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences. VIII-M-1-2021, 109–116 (2021).
52.
Glémarec, Y., Lugrin, J.- luc, Bosser, A.-G., Buche, C., Latoschik, M.E.: Conference Talk Training With a Virtual Audience System. ACM Symposium on Virtual Reality Software and Technology. (2021).
This paper presents the first prototype of a virtual audience sys-tem (VAS) specifically designed as a training tool for conferencetalks. This system has been tailored for university seminars dedi-cated to the preparation and delivery of scientific talks. We describethe required features which have been identified during the de-velopment process. We also summarize the preliminary feedbackreceived from lecturers and students during the first deployment ofthe system in seminars for bachelor and doctoral students. Finally,we discuss future work and research directions. We believe oursystem architecture and features are providing interesting insightson the development and integration of VR-based educational toolsinto university curriculum.
53.
Wamser, F., Seufert, A., Hall, A., Wunderer, S., Hoßfeld, T.: Valid Statements by the Crowd: Statistical Measures for Precision in Crowdsourced Mobile Measurements. Network. 1, 215–232 (2021).
Crowdsourced network measurements (CNMs) are becoming increasingly popular as they assess the performance of a mobile network from the end user’s perspective on a large scale. Here, network measurements are performed directly on the end-users’ devices, thus taking advantage of the real-world conditions end-users encounter. However, this type of uncontrolled measurement raises questions about its validity and reliability. The problem lies in the nature of this type of data collection. In CNMs, mobile network subscribers are involved to a large extent in the measurement process, and collect data themselves for the operator. The collection of data on user devices in arbitrary locations and at uncontrolled times requires means to ensure validity and reliability. To address this issue, our paper defines concepts and guidelines for analyzing the precision of CNMs; specifically, the number of measurements required to make valid statements. In addition to the formal definition of the aspect, we illustrate the problem and use an extensive sample data set to show possible assessment approaches. This data set consists of more than 20.4 million crowdsourced mobile measurements from across France, measured by a commercial data provider.
54.
Seufert, A., Schröder, S., Seufert, M.: Delivering User Experience over Networks: Towards a Quality of Experience Centered Design Cycle for Improved Design of Networked Applications. SN Computer Science. 2, (2021).
To deliver the best user experience (UX), the human-centered design cycle (HCDC) serves as a well-established guideline to application developers. However, it does not yet cover network-specific requirements, which become increasingly crucial, as most applications deliver experience over the Internet. The missing network-centric view is provided by Quality of Experience (QoE), which could team up with UX towards an improved overall experience. By considering QoE aspects during the development process, it can be achieved that applications become network-aware by design. In this paper, the Quality of Experience Centered Design Cycle (QoE-CDC) is proposed, which provides guidelines on how to design applications with respect to network-specific requirements and QoE. Its practical value is showcased for popular application types and validated by outlining the design of a new smartphone application. We show that combining HCDC and QoE-CDC will result in an application design, which reaches a high UX and avoids QoE degradation.
55.
Schaper, P., Donnermann, M., Doser, N., Lein, M., Riedmann, A., Steinhaeusser, S.C., Karageorgos, P., Müller, B., Richter, T., Lugrin, B.: Towards a digital syllable-based reading intervention: An interview study with second-graders. British HCI Conference 2021 (BCS-HCI 2021) (2021).
56.
Bartl, A., Wenninger, S., Wolf, E., Botsch, M., Latoschik, M.E.: Affordable but not Cheap: A Case Study of the Effects of Two 3D-Reconstruction Methods of Virtual Humans. Frontiers in Virtual Reality. 2, (2021).
Realistic and lifelike 3D-reconstruction of virtual humans has various exciting and important use cases. Our and others' appearances have notable effects on ourselves and our interaction partners in virtual environments, e.g., on acceptance, preference, trust, believability, behavior (the Proteus effect), and more. Today, multiple approaches for the 3D-reconstruction of virtual humans exist. They significantly vary in terms of the degree of achievable realism, the technical complexities, and finally, the overall reconstruction costs involved. This article compares two 3D-reconstruction approaches with very different hardware requirements. The high-cost solution uses a typical complex and elaborated camera rig consisting of 94 digital single-lens reflex (DSLR) cameras. The recently developed low-cost solution uses a smartphone camera to create videos that capture multiple views of a person. Both methods use photogrammetric reconstruction and template fitting with the same template model and differ in their adaptation to the method-specific input material. Each method generates high-quality virtual humans ready to be processed, animated, and rendered by standard XR simulation and game engines such as Unreal or Unity. We compare the results of the two 3D-reconstruction methods in an immersive virtual environment against each other in a user study. Our results indicate that the virtual humans from the low-cost approach are perceived similarly to those from the high-cost approach regarding the perceived similarity to the original, human-likeness, beauty, and uncanniness, despite significant differences in the objectively measured quality. The perceived feeling of change of the own body was higher for the low-cost virtual humans. Quality differences were perceived more strongly for one's own body than for other virtual humans.
57.
Metzger, F., Rafetseder, A., Schröder, S., Zwickl, P.: The Prospects of Cloud Gaming: Do the Benefits Outweigh the Costs?, (2021).
58.
von Mammen, S.: Motivating Interactive Self-Organisation. Lifelike Computing Systems Workshop 2020 and 2021. (2021).
59.
Loh, F., Mehling, N., Metzger, F., Hoßfeld, T.: LoRaPlan: A Software to Evaluate Gateway Placement in LoRaWAN. 17th International Conference on Network and Service Management. (2021).
Long Range Wide Area Network (LoRaWAN) is one of the fastest growing Internet of Things (IoT) access network solutions. One major challenge in current LoRaWAN planning is message collision due to the random channel access. To study the collision behavior in LoRaWAN, we present LoRaPlan in this demonstration. LoRaPlan is a software to evaluate gateway placement decisions by studying the collision probability. Therefore, sensor and gateway locations can be imported to create a LoRaWAN. Furthermore, existing networks can be extended by additional gateways. Based on this setup, network coverage, network quality with regard to the number of sensors a single gateway has to manage, and also transmission quality and collision probabilities can be studied. In this demonstration, first the process of network creation with gateway and sensor import and additional manual gateway placement in LoRaPlan is presented. Different adjustable parameters are shown and the influence on network coverage and collision probability is discussed. At the end of this demonstration, it is possible for the audience to place their own gateways and evaluate own placements by means of collision probability and the coverage.
60.
Lugrin, B.: Introduction to Socially Interactive Agents. In: Lugrin, B., Pelachaud, C., und Traum, D. (hrsg.) The Handbook on Socially Interactive Agents – 20 Years of Research on Embodied Conversational Agents, Intelligent Virtual Agents, and Social Robotics, Volume 1: Methods, Behavior, Cognition. S. 1–20. ACM (2021).
61.
Supervisor: Wehner, N.: Designing a Tool for Configurable Webpage Loading Behavior in the Wild, (2021).
Contact: nikolas.wehner@uni-wuerzburg.de Abstract: Web QoE studies often require accurate control of web page loading behavior. However, simply shaping the network conditions results in an often arbitrary web page loading behavior. An alternative approach with a more fine-grained control is thus the simulation of the web page loading behavior by making elements appear to specific points in time, independent of the network conditions. This is easy when the web page and its corresponding DOM elements are known beforehand, which is for example the case when using custom web pages in studies. These custom webpages often miss representativity though. The goal of this thesis is to create a tool which allows to apply a targeted behavior on an arbitrary web page. The main idea is to first preload a page, monitor and select the relevant DOM elements, and then in a second step simulate a custom web page loading behavior by making the selected DOM elements appear to the targeted points in time, thus replaying the web page loading. The designed tool, which could be for example a Chrome extension, is then supposed to be used on a subset of common web pages to evaluate its feasibility.
62.
Plabst, L., Oberdörfer, S., Happel, O., Niebling, F.: Visualisation methods for patient monitoring in anaesthetic procedures using augmented reality. VRST ’21: 27th ACM Symposium on Virtual Reality Software and Technology, Osaka, Japan, December 2021 (2021).
In health care, there are still many devices with poorly designed user interfaces that can lead to user errors. Especially in acute care, an error can lead to critical conditions in patients. Previous research has shown that the use of augmented reality can help to better monitor the condition of patients and better detect unforeseen events. The system created in this work is intended to aid in the detection of changes in patient and equipment-data in order to increase detection of critical conditions or errors.
63.
Wieser, V.: Bandwidth Measurements in Mobile Scenarios using a Raspberry Pi, (2021).
64.
Hein, R.M., Wienrich, C., Latoschik, M.E.: A Systematic Review of Foreign Language Learning with Immersive Technologies (2001-2020). AIMS Electronics and Electrical Engineering. 5, 117–145 (2021).
This study provides a systematic literature review of research (2001–2020) in the field of teaching and learning a foreign language and intercultural learning using immersive technologies. Based on 2507 sources, 54 articles were selected according to a predefined selection criteria. The review is aimed at providing information about which immersive interventions are being used for foreign language learning and teaching and where potential research gaps exist. The papers were analyzed and coded according to the following categories: (1) investigation form and education level, (2) degree of immersion, and technology used, (3) predictors, and (4) criterions. The review identified key research findings relating the use of immersive technologies for learning and teaching a foreign language and intercultural learning at cognitive, affective, and conative levels. The findings revealed research gaps in the area of teachers as a target group, and virtual reality (VR) as a fully immersive intervention form. Furthermore, the studies reviewed rarely examined behavior, and implicit measurements related to inter- and trans-cultural learning and teaching. Inter- and transcultural learning and teaching especially is an underrepresented investigation subject. Finally, concrete suggestions for future research are given. The systematic review contributes to the challenge of interdisciplinary cooperation between pedagogy, foreign language didactics, and Human-Computer Interaction to achieve innovative teaching-learning formats and a successful digital transformation.
65.
Hein, R.M., Steinbock, J., Eisenmann, M., Latoschik, M.E., Wienrich, C.: Development of the InteractionSuitcase in Virtual Reality to Support Inter-and Transcultural Learning Processes in English as Foreign Language Education. DELFI 2021. (2021).
Immersion programs and the experiences they offer learners are irreplaceable. In times of Covid-19, social VR applications can offer enormous potential for the acquisition of inter- and transcultural competencies (ITC). Virtual objects (VO) could initiate communication and reflection processes between learners with different cultural backgrounds and therefore offer an exciting approach. Accordingly, we address the following research questions: (1) What is a sound way to collect objects for the InteractionSuitcase to promote ITC acquisition by means of Social VR? (2) For which aspects do students use the objects when developing an ITC learning scenario? (3) Which VO are considered particularly supportive to initiate and facilitate ITC learning? To answer these research questions, the virtual InteractionSuitcase will be designed and implemented. This paper presents the empirical preliminary work and interim results of the development and evaluation of the InteractionSuitcase, its usage, and the significance of this project for Human-Computer Interaction (HCI) and English as Foreign Language (EFL) research.
66.
Krop, P., Straka, S., Ullrich, M., Ertl, M., Latoschik, M.E.: IT-Supported request management for clinical radiology: Analyzing the Radiological Order Workflow through Contextual Interviews. Mensch und Computer 2021 (MuC ’21), September 5-8, 2021, Ingolstadt, Germany. S. 1–7. Association for Computing Machinery, New York, NY, USA (2021).
Requests for radiological examinations in large medical facilities are a distributed and complex process with potential health-related risks for patients. A user-centered qualitative analysis with contextual interviews uncovered nine core problems, which hinder work efficiency and patient care: (1) Difficulties to access patient data & requests, (2) the large number of phone calls, (3) restricted & abused access rights, (4) request status difficult to track, (5) paper notes used for patient data, (6) lack of assistance for data entry, (7) frustration through documentation, (8) IT-systems not self-explanatory, and (9) conflict between physicians and radiologists.Contextual interviews were found to be a well fitting method to analyze and understand this complex process with multiple user roles. This analysis showed that there is room for improvement in the underlying IT systems, workflows and infrastructure. Our data gave useful insight into solutions to these problems and how we can use technology to improve all aspects of the request management. We are currently addressing those issues with a user-centered design process to design and implement a mobile application, which we will present in future work.
67.
Hirth, M., Seufert, M., Lange, S., Meixner, M., Tran-Gia, P.: Performance Evaluation of Hybrid Crowdsensing and Fixed Sensor Systems for Event Detection in Urban Environments. Sensors. 21, 5880 (1–19) (2021).
Crowdsensing offers a cost-effective way to collect large amounts of environmental sensor data. However, the spatial distribution of crowdsensing sensors can hardly be influenced, as the participants carry the sensors, and, additionally, the quality of the crowdsensed data can vary significantly. Hybrid systems that use mobile users in conjunction with fixed sensors might help to overcome these limitations, as such system allow assessing the quality of the submitted crowdsensed data and provide sensor values where no crowdsensing data is available. In this work, we use a simulation study to first analyze a simple crowdsensing system concerning the detection performance of spatial events to highlight the potential and limitations of a pure crowdsourcing system. The results indicate that even if only a small share of inhabitants participates in crowdsensing, events that have locations correlated with the population density can be easily and quickly detected using such a system. On the contrary, events with uniformly randomly distributed locations are much harder to detect using a simple crowdsensing-based approach. A second evaluation shows that hybrid systems improve the detection probability and time. Finally, we illustrate how to compute the minimum number of fixed sensors for given detection time thresholds in our exemplary scenario.
68.
Oberdörfer, S., Heidrich, D., Birnstiel, S., Latoschik, M.E.: Enchanted by Your Surrounding? Measuring the Effects of Immersion and Design of Virtual Environments on Decision-Making. Frontiers in Virtual Reality. 2, 101 (2021).
69.
Khelloqi, S.: Evaluation of Data Augmentation for Machine Learning on Network Traffic, (2021).
70.
An, S.H.: Investigation of Timed Gates for Predictable Latency in Dynamic Networks, (2021).
Kontakt: alexej.grigorjew@uni-wuerzburg.de -- Moderne Systeme enthalten immer mehr Machine-to-Machine (M2M) Kommunikation, welche traditionell durch Bus-Systeme wie CAN und PROFIBUS unterstützt wurden. Neuere Systeme haben jedoch höhere Anforderungen an Bandbreite, Latenz und Zuverlässigkeit, weshalb langsam ein Übergang in Richtung Ethernet-Technologien stattfindet. Daraus entstanden sehr viele verschiedene Technologien, die im Grunde die gleichen Ziele verfolgen, aber untereinander nicht kompatibel sind. Die IEEE Standardisierungsgruppe Time-Sensitive Networking (TSN) versucht, durch diverse Erweiterungen der Ethernet-Standards eine einheitliche Definition der Mechanismen zu bilden. Ein bekannter Mechanismus zur Umsetzung von Echtzeitanforderungen sind Timed Gates. Dabei werden Gate Control Lists konfiguriert, die genau steuern, welcher Port im Netzwerk zu welcher Zeit senden darf, ähnlich wie bei Zugfahrplänen an Bahnhöfen. Oftmals erfolgt diese Konfiguration als globale Netzwerk-weite Optimierung, welche alle Switches genau auf einander abstimmt. Die dazu notwendige Rechenzeit erlaubt die Nutzung aber nur für statische Anwendungszwecke. In dynamischen Szenarien ändern sich die Verkehrsanforderungen regelmäßig, und entscheidungen müssen schneller getroffen werden. Stattdessen können Zeitfenster auch länger geöffnet bleiben, um eine ganze Reihe von Paketen übertragen zu können. Neue Verkehrsströme können dann dynamisch zu diesen Gruppen hinzugefügt werden, solange das Zeitfenster groß genug ist, ohne die Gate Control Lists neu zu berechnen. Sobald das Zeitfenster nicht mehr ausreicht, werden neue Verkehrsanfragen abgelehnt. Je länger ein Zeitfenster aber ist, desto mehr verzögert es jedoch die anderen Gruppen. Die Frage ist also, wie die Effizienz eines gegebenen Netzwerks von den Zeitfenstern abhängt. In dieser Arbeit soll ein kleines Framework geschrieben werden, das für ein gegebenes Netzwerk und für eine gegebene Zeitfensterkonfiguration berechnet, wie viele der Echtzeit-Verkehrsströme darin platziert werden können. In einer Parameterstudie soll damit empirisch ermittelt werden, wie die Effizienz einer Konfiguration von diesen Parametern abhängt.
71.
Casas, P., Wassermann, S., Wehner, N., Seufert, M., Schüler, J., Hoßfeld, T.: Mobile Web and App QoE Monitoring for ISPs - from Encrypted Traffic to Speed Index through Machine Learning. 13th Wireless and Mobile Networking Conference (WMNC), Best Paper Award. , Montreal, Canada (Virtual Conference) (2021).
72.
Theiner, M.: Profiling the E2E Delays of Streamed Video Games with the Camera Method, (2021).
Determining the E2E lag of actions in video games is not trivial since there is no built-in way to grasp the full lag, including that contributed by the input and output. A standardized method is to record both input and output with a high framerate camera and count the frames from a visible input event to the result on screen. Your job is to perform these measurements for different actions in a series of games, and examine the overhead game streaming generates for them. Note: It might currently not be possible to perform these experiments, as they rely on a physical testbench.
73.
Korger, A., Baumeister, J.: Rule-based Semantic Relation Extraction in Regulatory Documents. Learning. Knowledge. Data. Analytics. , Munich, Germany (2021).
74.
Ripka, G., Grafe, S., Latoschik, M.E.: Peer group supervision in Zoom and social VR-Preparing preservice teachers for planning and designing digital media integrated classes. EdMedia+ Innovate Learning. S. 602–616. Association for the Advancement of Computing in Education (AACE) (2021).
21-century challenges demand a change towards collaborative and constructive seminar designs in initial teacher education regarding preservice teachers acquiring meta-conceptual awareness (TPACK) about how to implement emerging technologies in their future profession. Against this background the paper addresses the following research questions: 1) How should a pedagogical concept for remote initial teacher education be designed to promote metacognitive learning processes of preservice teachers? 2) How do preservice teachers perceive these learning processes in video-based communication and social VR? Regarding the pedagogical concept, peer group supervision and an action-and development-oriented approach using Zoom and social VR were identified as relevant for an instructional design that provides collaborative and constructive learning processes for students. In this exploratory study, 17 students participated in two iterative cycles of peer group supervision performing design tasks in groups. A content analysis of reflective video statements and qualitative group interviews was carried out using a qualitative research design. Results indicate the successful implementation of peer group supervision. Regarding media's implementation, Zoom's screen-sharing option and breakout session benefitted the consultation process as well as social VR's "realistic" experience of creating a "sense of community".
75.
Gall, D., Roth, D., Stauffert, J.-P., Zarges, J., Latoschik, M.E.: Virtual Body Ownership Intensifies Emotional Responses to Virtual Stimuli. Frontiers in Psychology - Cognitive Science. 12, 3833 (2021).
Modulating emotional responses to virtual stimuli is a fundamental goal of many immersive interactive applications. In this study, we leverage the illusion of illusory embodiment and show that owning a virtual body provides means to modulate emotional responses. In a single-factor repeated-measures experiment, we manipulated the degree of illusory embodiment and assessed the emotional responses to virtual stimuli. We presented emotional stimuli in the same environment as the virtual body. Participants experienced higher arousal, dominance, and more intense valence in the high embodiment condition compared to the low embodiment condition. The illusion of embodiment thus intensifies the emotional processing of the virtual environment. This result suggests that artificial bodies can increase the effectiveness of immersive applications psychotherapy, entertainment, computer-mediated social interactions, or health applications.
76.
Sichermann, M.: Evaluting the Mobile Internet Experience in Bavaria from End User Perspective, (2021).
Derzeit gibt es sogenannte Datenprovider (siehe zB www.tutela.com), die über Mobile Apps Leistungsmessungen von 5G-Mobilfunknetzen machen. In dieser Arbeit sollen diverse Monitoring-Lösungen und -Konzepte, die im großen Umfang die Leistung von 5G bestimmen können (zB über Mobile Apps), untersucht werden. Bei Interesse und für weitere Details bitte melden! Florian Wamser
77.
Appel, M., Lugrin, B., Kühle, M., Heindl, C.: The emotional robotic storyteller: On the influence of affect congruency on narrative transportation, robot perception, and persuasion. Computers in Human Behavior. 106749 (2021).
78.
Chaplick, S., Kindermann, P., Klawitter, J., Rutter, I., Wolff, A.: Extending Partial Representations of Rectangular Duals with Given Contact Orientations. In: Calamoneri, T. und Coró, F. (hrsg.) Proc. 12th International Conference on Algorithms and Complexity (CIAC’21). S. 340–353. Springer-Verlag (2021).
79.
Halbig, A., Latoschik, M.E.: A Systematic Review of Physiological Measurements, Factors, Methods, and Applications in Virtual Reality. Frontiers in Virtual Reality. 2, 89 (2021).
Measurements of physiological parameters provide an objective, often non-intrusive, and (at least semi-)automatic evaluation and utilization of user behavior. In addition, specific hardware devices of Virtual Reality (VR) often ship with built-in sensors, i.e. eye-tracking and movements sensors. Hence, the combination of physiological measurements and VR applications seems promising. Several approaches have investigated the applicability and benefits of this combination for various fields of applications. However, the range of possible application fields, coupled with potentially useful and beneficial physiological parameters, types of sensor, target variables and factors, and analysis approaches and techniques is manifold. This article provides a systematic overview and an extensive state-of-the-art review of the usage of physiological measurements in VR. We identified 1,119 works that make use of physiological measurements in VR. Within these, we identified 32 approaches that focus on the classification of characteristics of experience, common in VR applications. The first part of this review categorizes the 1,119 works by field of application, i.e. therapy, training, entertainment, and communication and interaction, as well as by the specific target factors and variables measured by the physiological parameters. An additional category summarizes general VR approaches applicable to all specific fields of application since they target typical VR qualities. In the second part of this review, we analyze the target factors and variables regarding the respective methods used for an automatic analysis and, potentially, classification. For example, we highlight which measurement setups have been proven to be sensitive enough to distinguish different levels of arousal, valence, anxiety, stress, or cognitive workload in the virtual realm. This work may prove useful for all researchers wanting to use physiological data in VR and who want to have a good overview of prior approaches taken, their benefits and potential drawbacks.
80.
Oberdörfer, S., Heidrich, D., Birnstiel, S., Latoschik, M.E.: Measuring the Effects of Virtual Environment Design on Decision-Making. Proceedings of the 28th IEEE Conference on Virtual Reality and 3D User Interfaces Abstracts and Workshops (VR ’21). S. 442–443. IEEE (2021).
81.
Amir, M.: Relating Google’s Web Vitals and Web QoE in a Crowdsourcing Approach, (2021).
82.
Steininger, M., Kobs, K., Davidson, P., Krause, A., Hotho, A.: Density-based weighting for imbalanced regression. Machine Learning. (2021).
In many real world settings,imbalanced data impedes model performance of learning algorithms, like neural networks, mostly for rare cases. This is especially problematic for tasks focusing on these rare occurrences. For example, when estimating precipitation, extreme rainfall events are scarce but important considering their potential consequences. While there are numerous well studied solutions for classification settings, most of them cannot be applied to regression easily. Of the few solutions for regression tasks, barely any have explored cost-sensitive learning which is known to have advantages compared to sampling-based methods in classification tasks. In this work, we propose a sample weighting approach for imbalanced regression datasets called DenseWeight and a cost-sensitive learning approach for neural network regression with imbalanced data called DenseLoss based on our weighting scheme. DenseWeight weights data points according to their target value rarities through kernel density estimation (KDE). DenseLoss adjusts each data point’s influence on the loss according to DenseWeight, giving rare data points more influence on modeltraining compared to common data points. We show on multiple differently distributed datasets that DenseLoss significantly improves model performance for rare data points through its density-based weighting scheme. Additionally, we compare DenseLoss to the state-of-the-art method SMOGN, finding that our method mostly yields better performance. Our approach provides more control over model training as it enables us to actively decide on the trade-off between focusing on common or rare cases through a single hyperparameter, allowing the training of better models for rare data points.
83.
Fischer, E., Zoller, D., Hotho, A.: Comparison of Transformer-Based Sequential Product Recommendation Models for the Coveo Data Challenge. SIGIR Workshop On eCommerce. (2021).
84.
Dallmann, A., Zoller, D., Hotho, A.: A Case Study on Sampling Strategies for Evaluating Neural Sequential Item Recommendation Models. Fifteenth ACM Conference on Recommender Systems. ACM (2021).
85.
Unruh, F., Landeck, M., Oberdörfer, S., Lugrin, J.-L., Latoschik, M.E.: The Influence of Avatar Embodiment on Time Perception - Towards VR for Time-Based Therapy. Frontiers in Virtual Reality. 2, 71 (2021).
Psycho-pathological conditions, such as depression or schizophrenia, are often accompanied by a distorted perception of time. People suffering from this conditions often report that the passage of time slows down considerably and that they are ``stuck in time.'' Virtual Reality (VR) could potentially help to diagnose and maybe treat such mental conditions. However, the conditions in which a VR simulation could correctly diagnose a time perception deviation are still unknown. In this paper, we present an experiment investigating the difference in time experience with and without a virtual body in VR, also known as avatar. The process of substituting a person's body with a virtual body is called avatar embodiment. Numerous studies demonstrated interesting perceptual, emotional, behavioral, and psychological effects caused by avatar embodiment. However, the relations between time perception and avatar embodiment are still unclear. Whether or not the presence or absence of an avatar is already influencing time perception is still open to question. Therefore, we conducted a between-subjects design with and without avatar embodiment as well as a real condition (avatar vs. no-avatar vs. real). A group of 105 healthy subjects had to wait for seven and a half minutes in a room without any distractors (e.g., no window, magazine, people, decoration) or time indicators (e.g., clocks, sunlight). The virtual environment replicates the real physical environment. Participants were unaware that they will be asked to estimate their waiting time duration as well as describing their experience of the passage of time at a later stage. Our main finding shows that the presence of an avatar is leading to a significantly faster perceived passage of time. It seems to be promising to integrate avatar embodiment in future VR time-based therapy applications as they potentially could modulate a user's perception of the passage of time. We also found no significant difference in time perception between the real and the VR conditions (avatar, no-avatar), but further research is needed to better understand this outcome.
86.
Geissler, S., Lange, S., Linguaglossa, L., Rossi, D., Zinner, T., Hoßfeld, T.: Discrete-Time Modeling of NFV Accelerators that Exploit Batched Processing. ACM Transactions on Modeling and Performance Evaluation of Computing Systems. 6, 1–27 (2021).
87.
Seufert, A., Wamser, F., Wunderer, S., Hall, A., Hoßfeld, T.: Trust but Verify: Crowdsourced Mobile Network Measurements and Statistical Validity Measures. 2021 Joint European Conference on Networks and Communications & 6G Summit (EuCNC/6G Summit). , Porto, Portugal (virtual conference) (2021).
Network operators, regulators, and big data companies use crowdsourced measurements to study the performance of mobile networks on a large scale. Such a type of measurement is defined as the collection and processing of data measured by the crowd, here the crowd of mobile subscribers. Crowdsourced network measurements make it relatively easy and inexpensive to obtain large amounts of network data that also reflect the quality actually received by the end user. However, this measurement method also involves some uncertainties, since, for example, it is not possible to precisely control when, where and with which devices measurements are taken. Thus, there is a trade-off between the reliability of the individual measurement and the scope of the measurements. Therefore, how data of this type is analyzed is particularly important in order to obtain valid results. To address this issue, our paper defines concepts and guidelines for analyzing the validity of crowdsourced mobile network measurements. In particular, we address precision, for example the number of measurements needed to make valid statements, and also representativeness, for example the spatial and temporal distribution of the data. In addition to the formal definition of these two aspects, we illustrate the issue and possible evaluation approaches with the help of an extensive example data set. This data set consists of more than 11.7M crowdsourced mobile measurements from all over France, measured by a commercial mobile data provider. In the end, we provide an evaluation guideline and two possible use cases.
88.
Seufert, A., Wamser, F., Yarish, D., Macdonald, H., Hoßfeld, T.: QoE Models in the Wild: Comparing Video QoE Models Using a Crowdsourced Data Set. 2021 13th International Conference on Quality of Multimedia Experience (QoMEX). , Montreal, Canada (virtual conference) (2021).
Crowdsourced measurements solve the problem of being able to assess the performance of a communication network from an end-user perspective, but the new characteristics of the data pose new challenges for QoE modeling. In contrast to existing laboratory or network measurements, this type of measurement at the end-user device primarily involves taking a large number of short sample measurements, which, however, are rich in measured parameters, including many user-, application-, and device-related parameters. To test the applicability and to facilitate the integration of such data, we applied four QoE models from the literature to 290k worldwide video streaming measurements from a commercial data set from August to October 2020. In this work, we will therefore first describe the crowdsourcing video streaming data set to provide insights into the properties of video streaming KPIs in the real-world. Second, we run four popular QoE models using this data set, compare the resulting QoE scores, and derive the impact of individual KPIs for each model. We show that the models assess the QoE at least differently, but sometimes with contradicting statements. Reading this paper, it becomes evident that more work and subjective studies, based on real-world data like the one we have shown, are needed to extend the current QoE models.
89.
Oberdörfer, S., Birnstiel, S., Latoschik, M.E., Grafe, S.: Mutual Benefits: Interdisciplinary Education of Pre-Service Teachers and HCI Students in VR/AR Learning Environment Design. Frontiers in Education. 6, 233 (2021).
90.
Loh, F., Poignée, F., Wamser, F., Leidinger, F., Hoßfeld, T.: Uplink vs. Downlink: Machine Learning-Based Quality Prediction for HTTP Adaptive Video Streaming. Sensors. 21, 4172 (2021).
Streaming video is responsible for the bulk of Internet traffic these days. For this reason, Internet providers and network operators try to make predictions and assessments about the streaming quality for an end user. Current monitoring solutions are based on a variety of different machine learning approaches. The challenge for providers and operators nowadays is that existing approaches require large amounts of data. In this work, the most relevant quality of experience metrics, i.e., the initial playback delay, the video streaming quality, video quality changes, and video rebuffering events, are examined using a voluminous data set of more than 13,000 YouTube video streaming runs that were collected with the native YouTube mobile app. Three Machine Learning models are developed and compared to estimate playback behavior based on uplink request information. The main focus has been on developing a lightweight approach using as few features and as little data as possible, while maintaining state-of-the-art performance.
91.
Supervisor: Seufert, M.: Identifying User Behavior from Encrypted Video Streaming Traffic, (2021).
Contact/Kontakt: michael.seufert@uni-wuerzburg.de Title: Identifying User Behavior from Encrypted Video Streaming Traffic Abstract: In this work, existing PC- and app-based measurement frameworks have to be modified to conduct video streaming measurements with emulated user interactions. Application and network layer streaming information shall be extracted and analyzed to identify the emulated user interactions from the encrypted streaming traffic. Titel: Indentifizierung von Nutzerverhalten aus verschlüsseltem Videostreaming-Netzwerkverkehr Inhalt: In dieser Arbeit sollen existierende PC- und App-basierte Messframeworks modifiziert werden, um Messungen von Videostreaming durchzuführen und Nutzerinteraktionen zu emulieren. Streaminginformationen sollen auf Applikations- und Netzwerkschicht extrahiert werden, um die emulierten Nutzerinteraktionen aus dem verschlüsselten Videostreaming-Netzwerkverkehr zu identifizieren.
92.
Oberdörfer, S., Elsässer, A., Grafe, S., Latoschik, M.E.: Grab the Frog: Comparing Intuitive Use and User Experience of a Smartphone-only, AR-only, and Tangible AR Learning Environment. Proceedings of the 23rd International Conference on Mobile Human-Computer Interaction (MobileHCI ’21). (2021).
93.
Frank, F., Kaufmann, M., Kobourov, S., Mchedlidze, T., Pupyrev, S., Ueckerdt, T., Wolff, A.: Using the Metro-Map Metaphor for Drawing Hypergraphs. In: Bureš, T., Dondi, R., Gamper, J., Guerrini, G., Jurdziński, T., Pahl, C., Sikora, F., und Wong, P. (hrsg.) Proc. 47th Int. Conf. Current Trends Theory & Practice Comput. Sci. (SOFSEM’21). S. 361–372. Springer-Verlag (2021).
94.
Metzger, F., Stulier, N., Borchert, K., Hirth, M.: Relationship Status: It’s Complicated. Using APM as a QoE-qualifying Tempo Metric. Proceedings of the 13th International Conference on Quality of Multimedia Experience (QoMEX 2021) (2021).
95.
Frieling, M.: Evaluating the Interaction between Web and Video QoE with Crowdsourcing, (2021).
96.
Nguyen Huu, T., Trung Kien, N., Van Hoa, N., Thu Huong, T., Wamser, F., Hoßfeld, T.: Energy-Aware Service Function Chain Embedding in Edge-Cloud Environments for IoT Applications. IEEE Internet of Things Journal. (2021).
The implementation of IoT applications faces several challenges in practice, such as compliance with QoS requirements, resource constraints and energy consumption. In this context, the joint paradigm for IoT applications can resolve some of the issues arising in pure cloud computing scenarios, such as those related to latency, energy or privacy. Therefore, an environment could be promising for resource and energy-efficient IoT applications that implement VNF bound together into SFC. However, a resource and energy efficient SFC placement requires smart SFC embedding mechanisms in the environment, as several challenges arise, such as IoT service chain modeling and evaluation, the trade-off between resource allocation, energy efficiency and performance, and the resource dynamics. In this article, we address issues in modeling resource and energy utilization for IoT applications in environments. A smart traffic monitoring IP camera system is deployed as a use case for a realistic modeling of a service chain. The system is implemented in our testbed, which is designed and developed specifically to model and investigate the resource and energy utilization of SFC embedding strategies. A resource and energy-aware SFC strategy in the environment for IoT applications is then proposed. Our algorithm is able to cope with dynamic load and resource situations emerging from dynamic SFC requests. The strategy is evaluated systematically in terms of acceptance ratio of SFC requests, resource efficiency and utilization, power consumption, and VNF migrations depending on the offered system load. Results show that our strategy outperforms some existing approaches in terms of resource and energy efficiency, thus it overcomes the relevant challenges from practice and meets the demands of IoT applications.
97.
Raies, Y., von Mammen, S.: A Swarm Grammar-Based Approach to Virtual World Generation. In: Romero, J., Martins, T., und Rodríguez-Fernández, N. (hrsg.) Artificial Intelligence in Music, Sound, Art and Design. S. 459–474. Springer International Publishing, Cham (2021).
In this work we formulate and propose an extended version of the multi-agent Swarm Grammar (SG) model for the generation of virtual worlds. It unfolds a comparatively small database into a complex world featuring terrain, vegetation and bodies of water. This approach allows for adaptivity of generated assets to their environment, unbounded worlds and interactivity in their generation. In order to evaluate the model, we conducted sensitivity analyses at a local interaction scale. In addition, at a global scale, we investigated two virtual environments, discussing notable interactions, recurring configuration patterns, and obstacles in working with SGs. These analyses showed that SGs can create visually interesting virtual worlds, but require further work in ease of use. Lastly we identified which future extensions might shrink required database sizes.
98.
Grigorjew, A., Gray, N., Hoßfeld, T.: Dynamic Real-Time Stream Reservation with TAS and Shared Time Windows. 2nd International Workshop on Time-Sensitive and Deterministic Networking (TENSOR) (2021).
Motivated by new use cases such as industrial automation and in-vehicle communication, Time-Sensitive Networking is further improving the layer~2 standards for real-time communication in Ethernet networks. As periodic traffic is a common requirement in such scenarios, the Time Aware Shaper (TAS) is a highly popular mechanism that allows the realization of real-time guarantees in synchronized networks. Most applications in literature suggest to configure the TAS for full stream isolation such that the lowest delays can be achieved. However, this ``zero-queuing'' strategy requires a high amount of computational resources and time, as the configuration of the gate control lists of each port is a complex task, which is not suitable for scenarios with dynamically changing requirements. This paper presents a novel approach with shared time windows. In combination with stream reservation techniques that are commonly applied for asynchronous mechanisms, the network is able to accept new streams during operation without complex reconfiguration, while still benefiting from some degree of isolation compared to conventional asynchronous shapers. The evaluation shows that, given the right circumstances, the number of accepted real-time streams can be improved significantly.
99.
Schüler, J.: Real-time Video QoE Estimation for Network Management based on Feature Calculation on a 100Gbps Programmable Data Plane, (2021).
100.
Orsolic, I., Seufert, M.: On Machine Learning based Video QoE Estimation Across Different Networks. 16th International Conference on Telecommunications (ConTEL), Best Paper Award. , Zagreb, Croatia (Virtual Conference) (2021).
101.
Hoßfeld, T., Seufert, M., Naderi, B.: On Inter-Rater Reliability for Crowdsourced QoE. 13th International Conference on Quality of Multimedia Experience (QoMEX). , Montreal, Canada (Virtual Conference) (2021).
102.
Schmitt, P.: Exploratory Comparison of Contemporary Cloud Gaming Services, (2021).
Recently, Cloud Gaming services have once again risen in popularity, with more and more commercial offerings becoming available. Your job in this thesis would be to investigate and compare these services on a technical level and based on their network characteristics.
103.
Gray, N., Dietz, K., Seufert, M., Hoßfeld, T.: High Performance Network Metadata Extraction Using P4 for ML-Based Intrusion Detection Systems. 22nd International Conference on High Performance Switching and Routing (HPSR). , Paris, France (Virtual Conference) (2021).
104.
Supervisor: Seufert, M.: Transfer Learning for QoE Monitoring of Encrypted Video Streaming Traffic, (2021).
Contact/Kontakt: michael.seufert@uni-wuerzburg.de Title: Transfer Learning for QoE Monitoring of Encrypted Video Streaming Traffic Abstract: This work is focused on Quality of Experience (QoE) monitoring of encrypted video streaming traffic. Here, machine learning based methods are used to estimate QoE metrics based on features or embeddings, which are extracted from the encrypted traffic. While these machine learning models achieve very good performance for a specific training data set, they typically show a worse performance when applied to different data sets. Thus, in this thesis, transfer learning approaches shall be tested and/or developed, which allow the existing models to generalize also over heterogeneous data sets. The performance of the transfer learning approaches shall be evaluated and a methodology for generalizing machine learning based QoE monitoring models shall be developed. Titel: Transferlernen bei der QoE Messung auf verschlüsseltem Videostreamingverkehr Inhalt: Diese Arbeit beschäftigt sich mit der QoE Messung auf verschlüsseltem Videostreamingverkehr. Hierbei werden Methoden des maschinellen Lernens (ML) eingesetzt um QoE-Metriken zu schätzen basierend auf Features oder Embeddings, die aus dem verschlüsselten Verkehr extrahiert werden. Während diese ML-Modelle sehr gute Leistung für spezifische Datensätze zeigen, haben sie typischerweise eine schlechtere Leistung wenn sie auf andere Datensätze angewandt werden. Deshalb sollen in dieser Arbeit Transferlernverfahren getestet und/oder entwickelt werden, die es erlauben, dass die existierenden Modelle auch für heterogene Datensätze verallgemeinert werden können. Die Leistung der Transferlernansätze soll bewertet werden und eine Methodik für die Generalisierung von ML-Modellen für QoE Messungen soll entwickelt werden.
105.
Grigorjew, A., Baier, C., Metzger, F., Hoßfeld, T.: Distributed Implementation of Deterministic Networking in Existing Non-TSN Ethernet Switches. Workshop on Time-sensitive and Deterministic Networking (TsDN) (2021).
Deterministic networking is quickly gaining importance, as several domains previously dominated by bus systems are now switching to Ethernet. While standardization efforts, especially from the Time-Sensitive Networking (TSN) group, are ongoing, practical deployments are still far off until configuration guidelines and resource management are able to use these tools to their full potential. As an alternative, this work presents a working implementation of bounded latency with an off-the-shelf non-TSN Ethernet switch. The solution is based on a distributed reservation protocol and admission control. It proves that bounded latency is already possible with simple priority-based transmission, and it provides valuable insights for the development and operation of future real-time networking solutions.
106.
Wehner, N., Seufert, M., Schüler, J., Wassermann, S., Casas, P., Hoßfeld, T.: Improving Web QoE Monitoring for Encrypted Network Traffic through Time Series Modeling. ACM SIGMETRICS Performance Evaluation Review. 48, 37–40 (2021).
This paper addresses the problem of Quality of Experience (QoE) monitoring for web browsing. In particular, the inference of common Web QoE metrics such as Speed Index (SI) is investigated. Based on a large dataset collected with open web-measurement platforms on different device-types, a unique feature set is designed and used to estimate the RUMSI -- an efficient approximation to SI, with machine-learning based regression and classification approaches. Results indicate that it is possible to estimate the RUMSI accurately, and that in particular, recurrent neural networks are highly suitable for the task, as they capture the network dynamics more precisely.
107.
Glémarec, Y., Lugrin, J.-L., Bosser, A.-G., Collins Jackson, A., Buche, C., Latoschik, M.E.: Indifferent or Enthusiastic? Virtual Audiences Animation and Perception in Virtual Reality. Frontiers in Virtual Reality. 2, 72 (2021).
In this paper, we present a virtual audience simulation system for Virtual Reality (VR). The system implements an audience perception model controlling the nonverbal behaviors of virtual spectators, such as facial expressions or postures. Groups of virtual spectators are animated by a set of nonverbal behavior rules representing a particular audience attitude (e.g., indifferent or enthusiastic). Each rule specifies a nonverbal behavior category: posture, head movement, facial expression and gaze direction as well as three parameters: type, frequency and proportion. In a first user-study, we asked participants to pretend to be a speaker in VR and then create sets of nonverbal behaviour parameters to simulate different attitudes. Participants manipulated the nonverbal behaviours of single virtual spectator to match a specific levels of engagement and opinion toward them. In a second user-study, we used these parameters to design different types of virtual audiences with our nonverbal behavior rules and evaluated their perceptions. Our results demonstrate our system’s ability to create virtual audiences with three types of different perceived attitudes: indifferent, critical, enthusiastic. The analysis of the results also lead to a set of recommendations and guidelines regarding attitudes and expressions for future design of audiences for VR therapy and training applications.
108.
Kern, F., Kullmann, P., Ganal, E., Korwisi, K., Stingl, R., Niebling, F., Latoschik, M.E.: Off-The-Shelf Stylus: Using XR Devices for Handwriting and Sketching on Physically Aligned Virtual Surfaces. Frontiers in Virtual Reality. 2, 69 (2021).
This article introduces the Off-The-Shelf Stylus (OTSS), a framework for 2D interaction (in 3D) as well as for handwriting and sketching with digital pen, ink, and paper on physically aligned virtual surfaces in Virtual, Augmented, and Mixed Reality (VR, AR, MR: XR for short). OTSS supports self-made XR styluses based on consumer-grade six-degrees-of-freedom XR controllers and commercially available styluses. The framework provides separate modules for three basic but vital features: 1) The stylus module provides stylus construction and calibration features. 2) The surface module provides surface calibration and visual feedback features for virtual-physical 2D surface alignment using our so-called 3ViSuAl procedure, and surface interaction features. 3) The evaluation suite provides a comprehensive test bed combining technical measurements for precision, accuracy, and latency with extensive usability evaluations including handwriting and sketching tasks based on established visuomotor, graphomotor, and handwriting research. The framework’s development is accompanied by an extensive open source reference implementation targeting the Unity game engine using an Oculus Rift S headset and Oculus Touch controllers. The development compares three low-cost and low-tech options to equip controllers with a tip and includes a web browser-based surface providing support for interacting, handwriting, and sketching. The evaluation of the reference implementation based on the OTSS framework identified an average stylus precision of 0.98 mm (SD = 0.54 mm) and an average surface accuracy of 0.60 mm (SD = 0.32 mm) in a seated VR environment. The time for displaying the stylus movement as digital ink on the web browser surface in VR was 79.40 ms on average (SD = 23.26 ms), including the physical controller’s motion-to-photon latency visualized by its virtual representation (M = 42.57 ms, SD = 15.70 ms). The usability evaluation (N = 10) revealed a low task load, high usability, and high user experience. Participants successfully reproduced given shapes and created legible handwriting, indicating that the OTSS and it’s reference implementation is ready for everyday use. We provide source code access to our implementation, including stylus and surface calibration and surface interaction features, making it easy to reuse, extend, adapt and/or replicate previous results (https://go.uniwue.de/hci-otss).
109.
Zehe, A., Konle, L., Dümpelmann, L., Gius, E., Hotho, A., Jannidis, F., Kaufmann, L., Krug, M., Puppe, F., Reiter, N., Schreiber, A., Wiedmer, N.: Detecting Scenes in Fiction: A new Segmentation Task. Proceedings of the 16th Conference of the European Chapter of the Association for Computational Linguistics: Volume 1, Long Papers. ACL (2021).
110.
Arseneva, E., Kleist, L., Klemz, B., Löffler, M., Schulz, A., Vogtenhuber, B., Wolff, A.: Adjacency Graphs of Polyhedral Surfaces. In: Buchin, K. und Colin de Verdière, Éric (hrsg.) Proc. 37th Annu. Sympos. Comput. Geom. (SoCG’21). S. 11:1–11:17. Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2021).
111.
Donnermann, M., Lein, M., Messingschlager, T., Riedmann, A., Schaper, P., Steinhaeusser, S., Lugrin, B.: Social robots and gamification for technology supported learning: An empirical study on engagement and motivation. Computers in Human Behavior. 121, 106792 (2021).
112.
Oesen, E.: Machine Learning Based Web QoE Monitoring for Encrypted Network Traffic, (2021).
113.
Döllinger, N., Wienrich, C., Latoschik, M.E.: Challenges and Opportunities of Immersive Technologies for Mindfulness Meditation: A Systematic Review. Frontiers in Virtual Reality. 2, 29 (2021).
Mindfulness is considered an important factor of an individual's subjective well-being. Consequently, Human-Computer Interaction (HCI) has investigated approaches that strengthen mindfulness, i.e., by inventing multimedia technologies to support mindfulness meditation. These approaches often use smartphones, tablets, or consumer-grade desktop systems to allow everyday usage in users' private lives or in the scope of organized therapies. Virtual, Augmented, and Mixed Reality (VR, AR, MR; in short: XR) significantly extend the design space for such approaches. XR covers a wide range of potential sensory stimulation, perceptive and cognitive manipulations, content presentation, interaction, and agency. These facilities are linked to typical XR-specific perceptions that are conceptually closely related to mindfulness research, such as (virtual) presence and (virtual) embodiment. However, a successful exploitation of XR that strengthens mindfulness requires a systematic analysis of the potential interrelation and influencing mechanisms between XR technology, its properties, factors, and phenomena and existing models and theories of the construct of mindfulness. This article reports such a systematic analysis of XR-related research from HCI and life sciences to determine the extent to which existing research frameworks on HCI and mindfulness can be applied to XR technologies, the potential of XR technologies to support mindfulness, and open research gaps. Fifty papers of ACM Digital Library and National Institutes of Health's National Library of Medicine (PubMed) with and without empirical efficacy evaluation were included in our analysis. The results reveal that at the current time, empirical research on XR-based mindfulness support mainly focuses on therapy and therapeutic outcomes. Furthermore, most of the currently investigated XR-supported mindfulness interactions are limited to vocally guided meditations within nature-inspired virtual environments. While an analysis of empirical research on those systems did not reveal differences in mindfulness compared to non-mediated mindfulness practices, various design proposals illustrate that XR has the potential to provide interactive and body-based innovations for mindfulness practice. We propose a structured approach for future work to specify and further explore the potential of XR as mindfulness-support. The resulting framework provides design guidelines for XR-based mindfulness support based on the elements and psychological mechanisms of XR interactions.
114.
Büttner, J., Merz, C., von Mammen, S.: Playing with Dynamic Systems - Battling Swarms in Virtual Reality. In: Castillo, P.A. und Jiménez Laredo, J.L. (hrsg.) Applications of Evolutionary Computation. S. 309–324. Springer International Publishing, Cham (2021).
In this paper, we present a serious game with the goal to provide an engaging and immersive experience to foster the players' understanding of dynamic networked systems. Confronted with attacking swarm networks, the player has to analyse their underlying network topologies and to systematically dismantle the swarms using a set of different weapons. We detail the game design, including the artificial intelligence of the swarm, the play mechanics and the level designs. Finally, we conducted an analysis of the play performances of a test group over the course of the game which revealed a positive learning outcome.
115.
Engelbrecht, T.: Investigating the Relationship of Network Data Arrival and the Rendering Process in Chrome, (2021).
116.
Mara, M., Stein, J.-P., Latoschik, M.E., Lugrin, B., Schreiner, C., Hostettler, R., Appel, M.: User Responses to a Humanoid Robot Observed in Real Life, Virtual Reality, 3D and 2D. Frontiers in Psychology - Human-Media Interaction. 12, 1152 (2021).
Humanoid robots (i.e., robots with a human-like body) are projected to be mass marketed in the future in several fields of application. Today, however, user evaluations of humanoid robots are often based on mediated depictions rather than actual observations or interactions with a robot, which holds true not least for scientific user studies. People can be confronted with robots in various modes of presentation, among them (1) 2D videos, (2) 3D, i.e., stereoscopic videos, (3) immersive Virtual Reality (VR), or (4) live on site. A systematic investigation into how such differential modes of presentation influence user perceptions of a robot is still lacking. Thus, the current study systematically compares the effects of different presentation modes with varying immersive potential on user evaluations of a humanoid service robot. Participants (N = 120) observed an interaction between a humanoid service robot and an actor either on 2D or 3D video, via a virtual reality headset (VR) or live. We found support for the expected effect of the presentation mode on perceived immediacy. Effects regarding the degree of human likeness that was attributed to the robot were mixed. The presentation mode had no influence on evaluations in terms of eeriness, likability, and purchase intentions. Implications for empirical research on humanoid robots and practice are discussed.
117.
Supervisor: Seufert, M.: Studying TCP/QUIC Performance for Competing Flow Access in a Testbed, (2021).
Contact/Kontakt: michael.seufert@uni-wuerzburg.de --- Abstract: In this project or thesis, a testbed shall be setup. The testbed shall emulate users, which browse web pages or stream videos via a shared link. The competition of the flows on the shared link shall be evaluated based on measurement studies in different scenarios. For this, especially the resulting Quality of Experience (QoE) shall be compared with respect to the used transport protocol, i.e., TCP or QUIC. --- Inhalt: In diesem Praktikum/Arbeit soll ein Testbed aufgebaut werden. Das Testbed soll Nutzer emulieren, die über einen gemeinsamen Link Webseiten browsen oder Videos streaming. Die Konkurrenzsituation auf dem geteilten Link soll mittels Messstudien in verschiedenen Szenarien ausgewertet werden. Dabei soll vor allem die resultierende QoE (Quality of Experience, subjektiv empfundene Dienstgüte) verglichen werden beim Einsatz von unterschiedlichen Transportprotokollen, nämlich TCP und QUIC.
118.
Supervisor: Seufert, M.: Comparison of Web and Video QoE Perception, (2021).
Contact/Kontakt: michael.seufert@uni-wuerzburg.de --- Abstract: In this thesis, an existing framework for subjective QoE studies shall be modified. Several QoE study shall be implemented and conducted, which compare and investigate in detail the fundamental perception of web browsing and video streaming. The results of the QoE studies shall be evaluated. --- In dieser Arbeit soll ein existierendes Framework für subjektive Befragungen zur QoE modifiziert werden. Es sollen einige QoE Studien implementiert und durchgeführt werden, die die fundamentale Wahrnehmung von Webbrowsing und Videostreaming vergleichen und im Detail untersuchen. Die Ergebnisse der QoE Studien sollen ausgewertet werden.
119.
Leidinger, F.: Multi Agent Reinforcement Learning for Port Configuration of Time-Sensitive-Networking, (2021).
120.
Wienrich, C., Latoschik, M.E.: eXtended Artificial Intelligence: New Prospects of Human-AI Interaction Research. Frontiers in Virtual Reality. 2, 94 (2021).
Artificial Intelligence (AI) covers a broad spectrum of computational problems and use cases. Many of those implicate profound and sometimes intricate questions of how humans interact or should interact with AIs. Moreover, many users or future users do have abstract ideas of what AI is, significantly depending on the specific embodiment of AI applications. Human-centered-design approaches would suggest evaluating the impact of different embodiments on human perception of and interaction with AI. An approach that is difficult to realize due to the sheer complexity of application fields and embodiments in reality. However, here XR opens new possibilities to research human-AI interactions. The article's contribution is twofold: First, it provides a theoretical treatment and model of human-AI interaction based on an XR-AI continuum as a framework for and a perspective of different approaches of XR-AI combinations. It motivates XR-AI combinations as a method to learn about the effects of prospective human-AI interfaces and shows why the combination of XR and AI fruitfully contributes to a valid and systematic investigation of human-AI interactions and interfaces. Second, the article provides two exemplary experiments investigating the aforementioned approach for two distinct AI-systems. The first experiment reveals an interesting gender effect in human-robot interaction, while the second experiment reveals an Eliza effect of a recommender system. Here the article introduces two paradigmatic implementations of the proposed XR testbed for human-AI interactions and interfaces and shows how a valid and systematic investigation can be conducted. In sum, the article opens new perspectives on how XR benefits human-centered AI design and development.
121.
Steinhaeusser, S.C., Schaper, P., Akuffo, O.B., Friedrich, P., Ön, J., Lugrin, B.: Anthropomorphize me! - Effects of Robot Gender on Listeners’ Perception of the Social Robot NAO in a Storytelling Use Case. In: Bethel, C., Paiva, A., Broadbent, E., Feil-Seifer, D., und Szafir, D. (hrsg.) Companion of the 2021 ACM/IEEE International Conference on Human-Robot Interaction (HRI 2021). ACM (2021).
122.
Steinhaeusser, S.C., Schaper, P., Lugrin, B.: Comparing a Robotic Storyteller versus Audio Book with Integration of Sound Effects and Background Music. In: Bethel, C., Paiva, A., Broadbent, E., Feil-Seifer, D., und Szafir, D. (hrsg.) Companion of the 2021 ACM/IEEE International Conference on Human-Robot Interaction (HRI 2021). ACM (2021).
123.
Steinhaeusser, S.C., Gabel, J.J., Lugrin, B.: Your New Friend NAO vs. Robot No. 783 - Effects of Personal or Impersonal Framing in a Robotic Storytelling Use Case. In: Bethel, C., Paiva, A., Broadbent, E., Feil-Seifer, D., und Szafir, D. (hrsg.) Companion of the 2021 ACM/IEEE International Conference on Human-Robot Interaction (HRI 2021). ACM (2021).
124.
Supervisor: Seufert, M.: Data Augmentation of Network Traffic Traces, (2021).
Contact/Kontakt: michael.seufert@uni-wuerzburg.de --- Abstract: In this project, several approaches to data augmentation for network traffic traces shall be implemented and evaluated. The goal is to generate synthetic traffic traces, which have almost identical properties to real traffic traces. This allows to reduce the amount of network traffic traces needed to train ML-based models. --- Inhalt: In diesem Praktikum sollen verschiedene Ansätze zur Datenanreicherung von Aufzeichnungen von Netzverkehr implementiert und evaluiert werden. Das Ziel ist es synthetische Verkehrsaufzeichnungen zu erzeugen, die beinahe identische Eigenschaften haben wie echte Verkehrsaufzeichnungen. Dies ermöglicht es die benötigte Menge von Aufzeichnungen von Netzverkehr beim Training von ML-basierten Modellen zu reduzieren.
125.
Funk, M.S.: Comparing Video QoE Models Using Subjective QoE Data Sets, (2021).
Contact: anika.seufert@informatik.uni-wuerzburg.de -- Inhalt: Der weltweite Videoverkehr hat in den letzten Jahren dramatisch zugenommen. Mit diesem rasanten Wachstum steigt auch das Interesse am Anwendungsverhalten von Video-Streaming-Diensten und dem daraus resultierenden Benutzererlebnis. Um mit Hilfe von objektiven Parametern (wie z. B. der Anzahl an Stalling Events oder Qualitätswechseln) die Zufriedenheit der Endnutzer (QoE) abzuschätzen, gibt es in der Literatur zahlreiche Modelle. Ziel dieser Arbeit ist es daher, einen Überblick über die Gemeinsamkeiten aber auch Unterschiede dieser QoE-Modelle zu bekommen. Dazu sollen mehrere Modelle implementiert werden und anhand verschiedenener subjektiver Video-Streaming-Datensätze verglichen werden. -- Abstract: Global video traffic has increased dramatically in recent years. With this rapid growth, there is also increasing interest in the application behavior of video streaming services and the resulting user experience (QoE). In order to estimate end-user satisfaction using objective parameters (such as the number of stalling events or quality changes), there are numerous models in the literature which can be used. Therefore, the goal of this thesis is to get an overview of the similarities but also differences of these QoE models. For this purpose, several models will be implemented and compared using different subjective video streaming datasets.
126.
Donnermann, M., Schaper, P., Lugrin, B.: Towards Adaptive Robotic Tutors in Universities: A Field Study. International Conference on Persuasive Technology (PERSUASIVE 2021). Springer (2021).
127.
Obremski, D., Lugrin, J.-L., Schaper, P., Lugrin, B.: Non-native speaker perception of Intelligent Virtual Agents in two languages: the impact of amount and type of grammatical mistakes. Journal on Multimodal User Interfaces. (2021).
Having a mixed-cultural membership becomes increasingly common in our modern society. It is thus beneficial in several ways to create Intelligent Virtual Agents (IVAs) that reflect a mixed-cultural background as well, e.g., for educational settings. For research with such IVAs, it is essential that they are classified as non-native by members of a target culture. In this paper, we focus on variations of IVAs' speech to create the impression of non-native speakers that are identified as such by speakers of two different mother tongues. In particular, we investigate grammatical mistakes and identify thresholds beyond which the agents is clearly categorised as a non-native speaker. Therefore, we conducted two experiments: one for native speakers of German, and one for native speakers of English. Results of the German study indicate that beyond 10% of word order mistakes and 25% of infinitive mistakes German-speaking IVAs are perceived as non-native speakers. Results of the English study indicate that beyond 50% of omission mistakes and 50% of infinitive mistakes English-speaking IVAs are perceived as non-native speakers. We believe these thresholds constitute helpful guidelines for computational approaches of non-native speaker generation, simplifying research with IVAs in mixed-cultural settings.
128.
Seybold, J.: Networking models and lag prevention methods of old games, (2021).
129.
Schweifler, R.: Evaluating the Impact of Browsing Delays on the QoE of Music Streaming, (2021).
Contact: anika.seufert@informatik.uni-wuerzburg.de -- Inhalt: Streaming wird heutzutage immer beliebter. Dazu zählt nicht nur das schon tiefgehend untersuchte Video-Streaming, auch Musik-Streaming über Applikationen wie Spotify wird immer populärer. Während bei Video-Streaming schon viele Untersuchungen zur Nutzerzufriedenheit und deren Einflussfaktoren gemacht wurden, gibt es bei Musik- bzw. Audio-Streaming bisher nur wenige Studien hierzu. In bisherigen QoE-Studien wurde das Streamen von Liedern separat von der verwendeten Applikation untersucht. Aus diesem Grund sollen in dieser Arbeit die Frage beantwortet werden, ob Nutzer den Musik-Stream als schlechter empfinden, wenn sie vorher eine schlechtere Erfahrung durch Browsing-Verzögerungen beim Benutzen der Applikation hatten. Dazu soll eine Web-Musik-Streaming-Applikation entworfen werden, um verschiedene Einflussfaktoren auf die QoE zu simulieren (z.B. Verzögerungen bei der Suche von Liedern oder beim Laden aller Titel einer Playliste). Anschließend wird eine subjektive Nutzerstudie durchgeführt und QoE-Bewertungen zur simulierten Verschlechterung gesammelt und ausgewertet. -- Abstract: Streaming is becoming more and more popular these days. This includes not only video streaming, which has already been studied in depth, but also music streaming via applications such as Spotify is becoming increasingly popular. While many studies have already been conducted on user satisfaction and its influencing factors for video streaming, there have only been a few studies on music and audio streaming. In previous QoE studies, the streaming of songs was examined separately from the application used. For this reason, this thesis aims to answer the question whether users perceive the music stream as worse if they previously had a worse experience due to browsing delays when using the application. For this purpose, a web music streaming application will be designed to simulate different factors influencing QoE (e.g., delays in searching songs or loading all tracks of a playlist). Subsequently, a subjective user study will be conducted and QoE ratings on the simulated degradation will be collected and evaluated.
130.
Wienrich, C., Döllinger, N.I., Hein, R.: Behavioral Framework of Immersive Technologies (BehaveFIT): How and Why Virtual Reality can Support Behavioral Change Processes. Frontiers Virtual Reality. 2, 84 (2021).
The design and evaluation of assisting technologies to support behavior change processes have become an essential topic within the field of human-computer interaction research in general and the field of immersive intervention technologies in particular. The mechanisms and success of behavior change techniques and interventions are broadly investigated in the field of psychology. However, it is not always easy to adapt these psychological findings to the context of immersive technologies. The lack of theoretical foundation also leads to a lack of explanation as to why and how immersive interventions support behavior change processes. The Behavioral Framework for immersive Technologies (BehaveFIT) addresses this lack by 1) presenting an intelligible categorization and condensation of psychological barriers and immersive features, by 2) suggesting a mapping that shows why and how immersive technologies can help to overcome barriers and finally by 3) proposing a generic prediction path that enables a structured, theory-based approach to the development and evaluation of immersive interventions. These three steps explain how BehaveFIT can be used, and include guiding questions for each step. Further, two use cases illustrate the usage of BehaveFIT. Thus, the present paper contributes to guidance for immersive intervention design and evaluation, showing that immersive interventions support behavior change processes and explain and predict 'why' and 'how' immersive interventions can bridge the intention-behavior-gap.
131.
Geißler, S., Wamser, F., Bauer, W., Krolikowski, M., Gebert, S., Hoßfeld, T.: Signaling Traffic in Internet-of-Things Mobile Networks. IFIP/IEEE International Symposium on Integrated Network Management (IM 2021). , Bordeaux, France (Virtual Conference) (2021).
The Internet of Things (IoT) is expected to play an increasingly important role in next-generation mobile networks. Detailed knowledge of this type of traffic and the associated signaling in those networks is of interest to operators and standardization in order to run these networks successfully. The aim of this study is to characterize IoT signaling traffic for mobile communication networks (i) from a network operator’s point of view, (ii) at device level, and (iii) for the establishment of data connections. General statistics on signaling and device behavior, such as the observed IoT traffic volume and message composition, are given before device classes with statistically different signaling behavior are identified. Finally, by characterizing the aggre- gated signaling traffic, we show that the Markov assumption, widespread in standardization and literature, regarding the aggregated arrival process for data connections does not apply in reality.
132.
Winter, C., Kern, F., Gall, D., Latoschik, M.E., Pauli, P., Käthner, I.: Immersive virtual reality during gait rehabilitation increases walking speed and motivation: A usability evaluation with healthy participants and patients with multiple sclerosis and stroke. Journal of NeuroEngineering and Rehabilitation. 18, (2021).
Background. The rehabilitation of gait disorders in multiple sclerosis (MS) and stroke patients is often based on conventional treadmill training. Virtual reality (VR)-based treadmill training can increase motivation and improve therapy outcomes. Objective. The present study aimed at (1) demonstrating the feasibility and acceptance of an immersive virtual reality application (presented via head-mounted display, HMD) for gait rehabilitation with patients, and (2) compare its effects to a semi-immersive presentation (via a monitor) and a conventional treadmill training without VR. Methods and results. 36 healthy participants and 14 persons with MS or stroke participated in each of the three experimental conditions. For both groups, the walking speed in the HMD condition was higher than in treadmill training without VR. Healthy participants reported a higher motivation after the HMD condition as compared with the other conditions. Importantly, no side effects in the sense of simulator sickness occurred and usability ratings were high. Most of the healthy study participants (89 %) and patients (71 %) preferred the HMD-based training among the three conditions and most patients could imagine using it more frequently. Conclusion. The study demonstrated the feasibility of combining a treadmill training with immersive VR. Due to its high usability and low side effects, the immersive system could serve as a valid alternative to conventional treadmill training in gait rehabilitation. It might be particularly suited for patients to improve training motivation and training outcome e. g. the walking speed compared with treadmill training using no or only semi-immersive VR.
133.
Latoschik, M.E., Wienrich, C.: Coherence and Plausibility, not Presence?! Pivotal Conditions for XR Experiences and Effects, a Novel Model. arXiv. (2021).
Presence often is considered the most important quale describing the subjective feeling of being in a computer-generated (virtual) or computer-mediated environment. The identification and separation of two 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. In this model, immersion is a proposed contributing factor to the place illusion. Lately, copresence and social presence illusions have extended this model, and coherence was proposed as a contributing factor to the plausibility illusion. Such factors strive to identify (objectively) measurable characteristics of an experience, e.g., systems properties that allow controlled manipulations of VR experiences. 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 as a consequence of a plausible generation of spatial cues, and similarly for all of the current model's so-defined illusions. Finally, we propose coherence and plausibility to become the central essential conditions in a novel theoretical model describing XR experiences and effects.
134.
Loh, F., Geißler, S., Schaible, F., Hoßfeld, T.: Talk to Me: Investigating the Traffic Characteristics of Amazon Echo Dot and Google Home. International Conference on Communications and Electronics, ICCE (2021).
The application area of smart speakers is steadily increasing with the Amazon Echo family and Google Home being brand leaders. Use cases include, among others, updating the calendar, home automation, or simply assisting users in their every day life. With the increasing amount of devices, the traffic generation and requesting process becomes a relevant subject to be studied in order to create traffic models and predict the impact on networks by these types of devices. Furthermore, with a detailed understanding of the devices, service quality can be monitored and improved for the end user. For that reason, in this work the requesting and traffic generation process of the Amazon Echo Dot and Google Home are studied and the generated network load of both devices is compared. With the insights of this study and additional device usage statistics, detailed traffic and usage models can be created.
135.
Antoniadis, A., Capretto, M., Chalermsook, P., Damerius, C., Kling, P., Nölke, L., Obscura, N., Spoerhase, J.: On Minimum Generalized Manhattan Connections. Proc. 17th Algorithms and Data Structures Symposium (WADS’21). S. 85–100 (2021).
136.
Grigorjew, A., Seufert, M., Wehner, N., Hofmann, J., Hoßfeld, T.: ML-Assisted Latency Assignments in Time-Sensitive Networking. IFIP/IEEE International Symposium on Integrated Network Management (IM 2021). , Bordeaux, France (Virtual Conference) (2021).
Recent developments in industrial automation and invehicle communication have raised the requirements of real-time networking. Bus systems that were traditionally deployed in these fields cannot provide sufficient bandwidth and are now shifting towards Ethernet for their real-time communication needs. In this field, standardization efforts from the IEEE and the IETF have developed new data plane mechanisms such as shapers and schedulers, as well as control plane mechanisms such as reservation protocols to support their new requirements. However, their implementation and their optimal configuration remain an important factor for their efficiency. This work presents a machine learning framework that takes on the configuration task. Four different models are trained for the configuration of per-hop latency guarantees in a distributed resource reservation process and compared with respect to their real-time traffic capacity. The evaluation shows that all models provide good configurations for the provided scenarios, but more importantly, they represent a first step for a semi-automated configuration of parameters in Time-Sensitive Networking.
137.
Wehner, N., Seufert, M., Wieser, V., Casas, P., Capdehourat, G.: Quality that Matters: QoE Monitoring in Education Service Provider (ESP) Networks. IFIP/IEEE International Symposium on Integrated Network Management (IM 2021). , Bordeaux, France (Virtual Conference) (2021).
Education Service Providers (ESPs) play a crucial role in the digitization of education as they equip students and teachers with reliable devices and provide high quality Internet access at schools. This paper investigates four months worth of continuous measurements conducted by an ESP using a largescale, passive, in-device Quality of Experience (QoE) monitoring system deployed into a nationwide network of education-purpose devices. These measurements cover more than 800 education centers and about 4000 devices, used both in schools and at home. Using this rich dataset, we present an exhaustive characterization of the browsing behavior, and a quantification of the web and video QoE in this educational context. Web QoE results showed a better performance for school Wi-Fi networks compared to home connections, suggesting that several issues may arise for ESPs due to the increasing relevance of home-schooling caused by the COVID-19 pandemic.
138.
Mathiasch, J.: Comparative Smart City Simulation of LoRaWAN and NB-IoT, (2021).
Urban environments are the intended use case of LPWAN technologies. But which technology is best suited for a Smart City and large numbers of IoT devices? Your task is to set up a combined simulation environment that implements both LoRaWAN as well as NB-IoT and their respective high-level architectures. This serves as a framework to thoroughly scrutinize these technologies.
139.
Stauffert, J.-P., Korwisi, K., Niebling, F., Latoschik, M.E.: Ka-Boom!!! Visually Exploring Latency Measurements for XR. Extended Abstracts of the 2021 CHI Conference on Human Factors in Computing Systems. Association for Computing Machinery, Yokohama, Japan (2021).
Latency can be detrimental for the experience of Virtual Reality. High latency can lead to loss of performance and cybersickness. There are simple approaches to measure approximate latency and more elaborated for more insight into latency behavior. Yet there are still researchers who do not measure the latency of the system they are using to conduct VR experiments. This paper provides an illustrated overview of different approaches to measure latency of VR applications, as well as a small decision-making guide to assist in the choice of the measurement method. The visual style offers a more approachable way to understand how to measure latency.
140.
Chaplick, S., Kindermann, P., Klawitter, J., Rutter, I., Wolff, A.: Extending Partial Representations of Rectangular Duals with Given Contact Orientations. In: Philippou, A. und Georgiou, C. (hrsg.) Proceedings of the 12th International Conference on Algorithms and Complexity (CIAC’21) (2021).
A rectangular dual of a graph G is a contact representation of G with axis-aligned rectangles such that (i) no four rectangles share a point and (ii) the union of all rectangles is a rectangle. The 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. Combinatorially, a rectangular dual can be described by a regular edge labeling (REL), which determines the orientations of the rectangle contacts. We characterize the RELs that admit an extension, which leads to a linear-time testing algorithm. In the affirmative, we can construct an extension in linear time.
141.
Geiger, J., Cornelsen, S., Haunert, J.-H., Kindermann, P., Mchedlidze, T., Nöllenburg, M., Okamoto, Y., Wolff, A.: ClusterSets: Optimizing Planar Clusters in Categorical Point Data. Comput. Graphics Forum. 40, 471–481 (2021).
142.
Wolf, E., Merdan, N., Döllinger, N., Mal, D., Wienrich, C., Botsch, M., Latoschik, M.E.: The Embodiment of Photorealistic Avatars Influences Female Body Weight Perception in Virtual Reality. Proceedings of the 28th IEEE Virtual Reality Conference (VR ’21). S. 65–74 (2021).
Embodiment and body perception have become important research topics in the field of virtual reality (VR). VR is considered a particularly promising tool to support research and therapy in regard to distorted body weight perception. However, the influence of embodiment on body weight perception has yet to be clarified. To address this gap, we compared body weight perception of 56 female participants of normal weight using a VR application. They either (a) self-embodied a photorealistic, non-personalized virtual human and performed body movements in front of a virtual mirror or (b) only observed the virtual human as other's avatar (or agent) performing the same movements in front of them. Afterward, participants had to estimate the virtual human's body weight. Additionally, we considered the influence of the participants' body mass index (BMI) on the estimations and captured the participants' feelings of presence and embodiment. Participants estimated the body weight of the virtual human as their embodied self-avatars significantly lower compared to participants rating the virtual human as other's avatar. Furthermore, the estimations of body weight were significantly predicted by the participant's BMI with embodiment, but not without. Our results clearly highlight embodiment as an important factor influencing the perception of virtual humans' body weights in VR.
143.
Supervisor: Loh, F.: Studying mobility in a LoRaWAN Network, (2021).
144.
Hamzeheinejad, N., Roth, D., Monty, S., Breuer, J., Rodenberg, A., Latoschik, M.E.: The Impact of Implicit and Explicit Feedback on Performance and Experience during VR-Supported Motor Rehabilitation. 2021 IEEE Virtual Reality and 3D User Interfaces (VR). S. 382–391. IEEE (2021).
This paper examines the impact of implicit and explicit feedback in Virtual Reality (VR) on performance and user experience during motor rehabilitation. In this work, explicit feedback consists of visual and auditory cues provided by a virtual trainer, compared to traditional feedback provided by a real physiotherapist. Implicit feedback was generated by the walking motion of the virtual trainer accompanying the patient during virtual walks. Here, the potential synchrony of movements between the trainer and trainee is intended to create an implicit visual affordance of motion adaption. We hypothesize that this will stimulate the activation of mirror neurons, thus fostering neuroadaptive processes. We conducted a clinical user study in a rehabilitation center employing a gait robot. We investigated the performance outcome and subjective experience of four resulting VR-supported rehabilitation conditions: with/without explicit feedback, and with/without implicit (synchronous motion) stimulation by a virtual trainer. We further included two baseline conditions reflecting the current NonVR procedure in the rehabilitation center. Our results show that additional feedback generally resulted in better patient performance, objectively assessed by the necessary applied support force of the robot. Additionally, our VR supported rehabilitation procedure improved enjoyment and satisfaction, while no negative impacts could be observed. Implicit feedback and adapted motion synchrony by the virtual trainer led to higher mental demand, giving rise to hopes of increased neural activity and neuroadaptive stimulation.
145.
Oberdörfer, S., Straka, S., Latoschik, M.E.: Effects of Immersion and Visual Angle on Brand Placement Effectiveness. Proceedings of the 28th IEEE Conference on Virtual Reality and 3D User Interfaces Abstracts and Workshops (VR ’21). S. 440–441. IEEE (2021).
146.
Madeira, O., Gromer, D., Latoschik, M.E., Pauli, P.: Effects of Acrophobic Fear and Trait Anxiety on Human Behavior in a Virtual Elevated Plus-Maze. Frontiers in Virtual Reality. 2, 19 (2021).
The Elevated Plus-Maze (EPM) is a well-established apparatus to measure anxiety in rodents, i.e. animals exhibiting an increased relative time spent in the closed versus the open arms are considered anxious. To examine whether such anxiety-modulated behavior is conserved in humans, we re-translated this paradigm to a human setting using virtual reality in a Cave Automatic Virtual Environment (CAVE) system. In two studies, we examined whether the EPM exploration behavior of humans is modulated by their trait anxiety, but also assessed the individuals’ levels of acrophobia (fear of height), claustrophobia (fear of confined spaces), sensation seeking and the reported anxiety when on the maze. First, we constructed an exact virtual copy of the animal EPM adjusted to human proportions. In analogy to animal EPM studies, participants (N = 30) freely explored the EPM for five minutes. In the second study (N = 61), we redesigned the EPM to make it more human-adapted and to differentiate influences of trait anxiety and acrophobia by introducing various floor textures and lower walls of closed arms to the height of common handrails. In the first experiment, hierarchical regression analyses of exploration behavior revealed the expected association between open arm avoidance and Trait Anxiety, but an even stronger association with acrophobic fear. In the second study, results revealed that acrophobia was associated with avoidance of open arms with mesh-floor texture, whereas for trait anxiety, claustrophobia and sensation seeking no effect was detected. In addition, subjects’ fear rating was moderated by all psychometrics but trait anxiety. In sum, both studies consistently indicate that humans show no general open arm avoidance analogous to rodents and that human EPM behavior is modulated strongest by acrophobic fear, whereas trait anxiety plays a subordinate role. Thus, we conclude that the criteria for a cross-species validity are met insufficiently in this case. Despite of the exploratory nature, our studies provide in-depth insights into human exploration behavior on the virtual EPM.
147.
Vomhoff, V.: Investigating IoT-centric signaling traffic at the MVNO Mobile Core - Modeling and Classification, (2021).
148.
Geissler, S., Lange, S., Tran-Gia, P., Hoßfeld, T.: Discrete-time Analysis of Multicomponent GI/GI/1 Queueing Networks. Conference on Networked Systems (NetSys) (2021).
In this work, we provide initial insights regarding the error introduced into multicomponent queueing systems by assuming the departure processes of arbitrary GI/GI/1-∞ queues to be renewal processes. To this end, we compute the sojourn time distribution as well as departure distributions of a linear chain of queueing components and compare the results to a simulation of the same system. By applying the renewal approximation, potential autocorrelations of the departure processes are lost. We investigate the magnitude of this error regarding both the sojourn time as well as interdeparture time distributions for a broad set of parameters. Although more indepth studies are needed, our results show that both distributions can be closely approximated, which allows the application of the model to asses the performance of real world NFV function chains.
149.
Maier, C.: Assessment and Selection of Features for Transfer Learning of ML-based Intrusion Detection Systems, (2021).
The acquisition of adequate data is a crucial concern for Machine Learning (ML) and especially network security. Throughout the years, many publicly available data sets were released. One of the most cited data sets in this regard are the KDD-CUP-99 data set and its variation NL-KDD. Both suffer from obvious problems, like the age and imbalanced composition of the data. However, newer data sets have been created, e.g., through real-world measurements, simulation or a hybrid form of both. The goal of this thesis is to evaluate a variety of data sets on their own, but also compare them concerning their intercompatibility regarding training and testing for ML. This also includes the analysis of various factors, such as the underlying network structure (e.g., size and type), temporal classification and induced traffic (e.g., type of traffic and attacks or network load).
150.
Bartl, A., Jung, S., Kullmann, P., Wenninger, S., Achenbach, J., Wolf, E., Schell, C., Lindeman, R.W., Botsch, M., Latoschik, M.E.: Self-Avatars in Virtual Reality: A Study Protocol for Investigating the Impact of the Deliberateness of Choice and the Context-Match. Proceedings of the 28th IEEE Virtual Reality conference (VR ’21). IEEE (2021).
151.
Ebner, M.: Plausible Performance Prediction of Simulated SDN-enabled Networks via Machine Learning, (2021).
In recent years, Software-Defined Networking (SDN) emerged as an innovative network architecture and gained increasing popularity due to its centralized network management. However, this central point induces a potential bottleneck and possible single-point-of-failure to the network. Therefore, so-called distributed architectures come into play, which keep the logical view centralized, but physically distributed. The goal of this thesis is to evaluate two opposing approaches and predict their performance via Machine Learning (ML). The simulation will be conducted on basis of a preexisting framework based on OMNeT++, which already implements two distributed SDN-architectures, ready for simulation.
152.
Supervisor: Geissler, S.: Design and Implementation of a WebApp for the Performance Evaluation of VNF Chains, (2021).
Goal of this work is the design and implementation of a web-based application that allows the graphical configuration of service function chains (SFC). An underlying backend (written in R) should then perform detailed performance evaluation (discrete-time modeling, simulation) of the designed SFC and generate several key performance indicators of the system.
153.
Schaper, P., Riedmann, A., Lugrin, B.: Internalisation of Situational Motivation in an E-Learning Scenario Using Gamification. International Conference on Artificial Intelligence in Education (AIED 2021). S. 314–319. Springer (2021).
