@article{HalbigLatoschik2021, author = {Halbig, Andreas and Latoschik, Marc Erich}, title = {A systematic review of physiological measurements, factors, methods, and applications in virtual reality}, series = {Frontiers in Virtual Reality}, volume = {2}, journal = {Frontiers in Virtual Reality}, doi = {10.3389/frvir.2021.694567}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-260503}, year = {2021}, abstract = {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.}, language = {en} } @article{GrohmannHerbstChalbanietal.2020, author = {Grohmann, Johannes and Herbst, Nikolas and Chalbani, Avi and Arian, Yair and Peretz, Noam and Kounev, Samuel}, title = {A Taxonomy of Techniques for SLO Failure Prediction in Software Systems}, series = {Computers}, volume = {9}, journal = {Computers}, number = {1}, issn = {2073-431X}, doi = {10.3390/computers9010010}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-200594}, pages = {10}, year = {2020}, abstract = {Failure prediction is an important aspect of self-aware computing systems. Therefore, a multitude of different approaches has been proposed in the literature over the past few years. In this work, we propose a taxonomy for organizing works focusing on the prediction of Service Level Objective (SLO) failures. Our taxonomy classifies related work along the dimensions of the prediction target (e.g., anomaly detection, performance prediction, or failure prediction), the time horizon (e.g., detection or prediction, online or offline application), and the applied modeling type (e.g., time series forecasting, machine learning, or queueing theory). The classification is derived based on a systematic mapping of relevant papers in the area. Additionally, we give an overview of different techniques in each sub-group and address remaining challenges in order to guide future research.}, language = {en} } @inproceedings{SchlosserJarschelDuellietal.2010, author = {Schlosser, Daniel and Jarschel, Michael and Duelli, Michael and Hoßfeld, Tobias and Hoffmann, Klaus and Hoffmann, Marco and Morper, Hans Jochen and Jurca, Dan and Khan, Ashiq}, title = {A Use Case Driven Approach to Network Virtualization}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-55611}, year = {2010}, abstract = {In today's Internet, services are very different in their requirements on the underlying transport network. In the future, this diversity will increase and it will be more difficult to accommodate all services in a single network. A possible approach to cope with this diversity within future networks is the introduction of support for running isolated networks for different services on top of a single shared physical substrate. This would also enable easy network management and ensure an economically sound operation. End-customers will readily adopt this approach as it enables new and innovative services without being expensive. In order to arrive at a concept that enables this kind of network, it needs to be designed around and constantly checked against realistic use cases. In this contribution, we present three use cases for future networks. We describe functional blocks of a virtual network architecture, which are necessary to support these use cases within the network. Furthermore, we discuss the interfaces needed between the functional blocks and consider standardization issues that arise in order to achieve a global consistent control and management structure of virtual networks.}, subject = {Virtualisierung}, language = {en} } @techreport{AlfredssonKasslerVestinetal.2022, type = {Working Paper}, author = {Alfredsson, Rebecka and Kassler, Andreas and Vestin, Jonathan and Pieska, Marcus and Amend, Markus}, title = {Accelerating a Transport Layer based 5G Multi-Access Proxy on SmartNIC}, series = {W{\"u}rzburg Workshop on Next-Generation Communication Networks (WueWoWas'22)}, journal = {W{\"u}rzburg Workshop on Next-Generation Communication Networks (WueWoWas'22)}, doi = {10.25972/OPUS-28079}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-280798}, pages = {4}, year = {2022}, abstract = {Utilizing multiple access technologies such as 5G, 4G, and Wi-Fi within a coherent framework is currently standardized by 3GPP within 5G ATSSS. Indeed, distributing packets over multiple networks can lead to increased robustness, resiliency and capacity. A key part of such a framework is the multi-access proxy, which transparently distributes packets over multiple paths. As the proxy needs to serve thousands of customers, scalability and performance are crucial for operator deployments. In this paper, we leverage recent advancements in data plane programming, implement a multi-access proxy based on the MP-DCCP tunneling approach in P4 and hardware accelerate it by deploying the pipeline on a smartNIC. This is challenging due to the complex scheduling and congestion control operations involved. We present our pipeline and data structures design for congestion control and packet scheduling state management. Initial measurements in our testbed show that packet latency is in the range of 25 μs demonstrating the feasibility of our approach.}, subject = {Datennetz}, language = {en} } @techreport{BrischKasslerVestinetal.2023, type = {Working Paper}, author = {Brisch, Fabian and Kassler, Andreas and Vestin, Jonathan and Pieska, Marcus and Amend, Markus}, title = {Accelerating Transport Layer Multipath Packet Scheduling for 5G-ATSSS}, series = {KuVS Fachgespr{\"a}ch - W{\"u}rzburg Workshop on Modeling, Analysis and Simulation of Next-Generation Communication Networks 2023 (WueWoWAS'23)}, journal = {KuVS Fachgespr{\"a}ch - W{\"u}rzburg Workshop on Modeling, Analysis and Simulation of Next-Generation Communication Networks 2023 (WueWoWAS'23)}, doi = {10.25972/OPUS-32205}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-322052}, pages = {4}, year = {2023}, abstract = {Utilizing multiple access networks such as 5G, 4G, and Wi-Fi simultaneously can lead to increased robustness, resiliency, and capacity for mobile users. However, transparently implementing packet distribution over multiple paths within the core of the network faces multiple challenges including scalability to a large number of customers, low latency, and high-capacity packet processing requirements. In this paper, we offload congestion-aware multipath packet scheduling to a smartNIC. However, such hardware acceleration faces multiple challenges due to programming language and platform limitations. We implement different multipath schedulers in P4 with different complexity in order to cope with dynamically changing path capacities. Using testbed measurements, we show that our CMon scheduler, which monitors path congestion in the data plane and dynamically adjusts scheduling weights for the different paths based on path state information, can process more than 3.5 Mpps packets 25 μs latency.}, language = {en} } @phdthesis{Baunach2012, author = {Baunach, Marcel}, title = {Advances in Distributed Real-Time Sensor/Actuator Systems Operation - Operating Systems, Communication, and Application Design Concepts -}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-76489}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2012}, abstract = {This work takes a close look at several quite different research areas related to the design of networked embedded sensor/actuator systems. The variety of the topics illustrates the potential complexity of current sensor network applications; especially when enriched with actuators for proactivity and environmental interaction. Besides their conception, development, installation and long-term operation, we'll mainly focus on more "low-level" aspects: Compositional hardware and software design, task cooperation and collaboration, memory management, and real-time operation will be addressed from a local node perspective. In contrast, inter-node synchronization, communication, as well as sensor data acquisition, aggregation, and fusion will be discussed from a rather global network view. The diversity in the concepts was intentionally accepted to finally facilitate the reliable implementation of truly complex systems. In particular, these should go beyond the usual "sense and transmit of sensor data", but show how powerful today's networked sensor/actuator systems can be despite of their low computational performance and constrained hardware: If their resources are only coordinated efficiently!}, subject = {Eingebettetes System}, language = {en} } @phdthesis{Eichelberger2005, author = {Eichelberger, Holger}, title = {Aesthetics and automatic layout of UML class diagrams}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-14831}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2005}, abstract = {In the last years, visual methods have been introduced in industrial software production and teaching of software engineering. In particular, the international standardization of a graphical software engineering language, the Unified Modeling Language (UML) was a reason for this tendency. Unfortunately, various problems exist in concrete realizations of tools, e.g. due to a missing compliance to the standard. One problem is the automatic layout, which is required for a consistent automatic software design. The thesis derives reasons and criteria for an automatic layout method, which produces drawings of UML class diagrams according to the UML specification and issues of human computer interaction, e.g. readability. A unique set of aesthetic criteria is combined from four different disciplines involved in this topic. Based on these aethetic rules, a hierarchical layout algorithm is developed, analyzed, measured by specialized measuring techniques and compared to related work. Then, the realization of the algorithm as a Java framework is given as an architectural description. Finally, adaptions to anticipated future changes of the UML, improvements of the framework and example drawings of the implementation are given.}, subject = {URL}, language = {en} } @article{BartlWenningerWolfetal.2021, author = {Bartl, Andrea and Wenninger, Stephan and Wolf, Erik and Botsch, Mario and Latoschik, Marc Erich}, title = {Affordable but not cheap: a case study of the effects of two 3D-reconstruction methods of virtual humans}, series = {Frontiers in Virtual Reality}, volume = {2}, journal = {Frontiers in Virtual Reality}, doi = {10.3389/frvir.2021.694617}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-260492}, year = {2021}, abstract = {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.}, language = {en} } @techreport{GrigorjewDiederichHossfeldetal.2022, type = {Working Paper}, author = {Grigorjew, Alexej and Diederich, Philip and Hoßfeld, Tobias and Kellerer, Wolfgang}, title = {Affordable Measurement Setups for Networking Device Latency with Sub-Microsecond Accuracy}, series = {W{\"u}rzburg Workshop on Next-Generation Communication Networks (WueWoWas'22)}, journal = {W{\"u}rzburg Workshop on Next-Generation Communication Networks (WueWoWas'22)}, doi = {10.25972/OPUS-28075}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-280751}, pages = {5}, year = {2022}, abstract = {This document presents a networking latency measurement setup that focuses on affordability and universal applicability, and can provide sub-microsecond accuracy. It explains the prerequisites, hardware choices, and considerations to respect during measurement. In addition, it discusses the necessity for exhaustive latency measurements when dealing with high availability and low latency requirements. Preliminary results show that the accuracy is within ±0.02 μs when used with the Intel I350-T2 network adapter.}, subject = {Datennetz}, language = {en} } @phdthesis{Herrler2007, author = {Herrler, Rainer}, title = {Agentenbasierte Simulation zur Ablaufoptimierung in Krankenh{\"a}usern und anderen verteilten, dynamischen Umgebungen}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-24483}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2007}, abstract = {Verteilte dynamische Systeme unter lokalen und globalen Gesichtspunkten zu optimieren ist eine schwierige Aufgabe. Zwar sind grunds{\"a}tzliche Auswirkungen einzelner Maßnahmen h{\"a}ufig bekannt, durch widerstrebende Ziele, Wechselwirkungen zwischen Prozessen und Nebenwirkungen von Maßnahmen ist ein analytisches Vorgehen bei der Optimierung nicht m{\"o}glich. Besonders schwierig wird es, wenn lokale Einheiten einerseits ihre Ziele und Autonomie behalten sollen, aber durch zentrale Vorgaben bzw. Anreize so gesteuert werden sollen, dass ein {\"u}bergeordnetes Ziel erreicht wird. Ein praktisches Beispiel dieses allgemeinen Optimierungsproblems findet sich im Gesundheitswesen. Das Management von modernen Kliniken ist stets mit dem Problem konfrontiert, die Qualit{\"a}t der Pflege zu gew{\"a}hrleisten und gleichzeitig kosteneffizient zu arbeiten. Hier gilt es unter gegeben Rahmenbedingungen und bei Respektierung der Autonomie der Funktionseinheiten, Optimierungsmaßnahmen zu finden und durchzuf{\"u}hren. Vorhandene Werkzeuge zur Simulation und Modellierung bieten f{\"u}r diese Aufgabe keine ausreichend guten Vorgehensmodelle und Modellierungsmechanismen. Die agentenbasierte Simulation erm{\"o}glicht die Abbildung solcher Systeme und die Durchf{\"u}hrung von Simulationsexperimenten zur Bewertung einzelner Maßnahmen. Es werden L{\"o}sungswege und Werkzeuge vorgestellt und evaluiert, die den Benutzer bei der Formalisierung des Wissens und der Modellierung solch komplexer Szenarien unterst{\"u}tzen und ein systematisches Vorgehen zur Optimierung erm{\"o}glichen.}, subject = {Simulation}, language = {de} }