Lebenslauf:

Publikationen:

• Antons, Jan-Niklas; Egger, Sebastian; Hoßfeld, Tobias; Möller, Sebastian (Hrsg.): Proceedings of The Fifth Workshop on Perceptual Quality of Systems (PQS 2016), ISCA, TU Berlin, Germany 2017. BIB DownloadDetails
• Egger, Sebastian; Redi, Judith; Hoßfeld, Tobias; Hirth, Matthias; Möller, Sebastian; Naderi, Babak; Keimel, Chistian: Crowdsourcing for QoE Experiments. In: Archambault, Daniel; Hoßfeld, Tobias; Purchase; Helen; C. (Hrsg.): Evaluation in the Crowd: Crowsourcing and Human-Centred Experiments. Springer, ISBN 978-3-319-66435-4, 2017. VolltextBIB DownloadDetails
• Martin, David; Carpendale, Sheelagh; Gupta, Neha; Hoßfeld, Tobias; Naderi, Babak; Redi, Judith; Siahaan, Ernestasia; Wechsung, Ina: Understanding the Crowd: Ethical and Practical Matters in the Academic Use of Crowdsourcing. In: Archambault, Daniel; Hoßfeld, Tobias; Purchase; Helen; C. (Hrsg.): Evaluation in the Crowd: Crowsourcing and Human-Centred Experiments. Springer, ISBN 978-3-319-66435-4, 2017. VolltextBIB DownloadDetails
• Hossfeld, Tobias; Fiedler, Markus; Gustafsson, Jörgen: Betas: Deriving Quantiles from MOS-QoS Relations of IQX Models for QoE Management. In: Workshop, QoE-Management (Hrsg.): IEEE/IFIP IM 2017. Lisbon, Portugal 2017. VolltextBIB DownloadDetails
• Lareida, Andri; Hoßfeld, Tobias; Stiller, Burkhard: The BitTorrent Peer Collector Problem. In: Ieee (Hrsg.): Integrated Network and Service Management (IM), 2017 IFIP/IEEE. Lisbon, Portugal 2017. doi:10.23919/INM.2017.7987311VolltextBIB DownloadDetails
• Hossfeld, Tobias; Skorin-Kapov, Lea; Heegaard, Poul E.; Varela, Martín: Definition of QoE Fairness in Shared Systems. In: Society, Ieee Communications; Electrical, Institute Of; Electronics Engineers, Institute of Electrical; Engineers, Electronics (Hrsg.): IEEE Communications Letters, Volume: 21. 2016. doi:10.1109/LCOMM.2016.2616342VolltextBIB DownloadDetails
• Moldovan, Christian; Hoßfeld, Tobias: Impact of Variances on the QoE in Video Streaming. In: QCMAN 2016 : Fourth IEEE International Workshop on Quality of Experience Centric Management. Würzburg 2016. VolltextBIB DownloadDetails
• Moldovan, Christian; Sieber, Christian; Heegaard, Poul; Kellerer, Wolfgang; Hoßfeld, Tobias: YouTube Can Do Better: Getting the Most Out of Video Adaptation. In: QCMAN 2016 : Fourth IEEE International Workshop on Quality of Experience Centric Management. Würzburg 2016. VolltextBIB DownloadDetails
• Hoßfeld, Tobias; Heegaard, Poul E.; Varela, Martín; Möller, Sebastian: QoE Beyond the MOS: An In-Depth Look at QoE via Better Metrics and their Relation to MOS. In: Quality and User Experience (2016). doi:10.1007/s41233-016-0002-1VolltextBIB DownloadDetails
• Metzger, Florian; Lioutou, Eirini; Moldovan, Christian; Hoßfeld, Tobias: TCP Video Streaming and Mobile Networks: Not A Love Story, But Better With Context. In: Special Issue of Computer Networks on “Traffic and Performance in the Big Data Era”, Jg. 2016 (2016). VolltextBIB DownloadDetails
• Hoßfeld, Tobias; Skorin-Kapov, Lea; Heegaard, Poul E.; Varela, Martìn; Chen, Kuan-Ta: On Additive and Multiplicative QoS-QoE Models for Multiple QoS Parameters. In: PQS 2016. Berlin 2016. VolltextBIB DownloadDetails
• Seufert, Michael; Hoßfeld, Tobias: One Shot Crowdtesting: Approaching the Extremes of Crowdsourced Subjective Quality Testing. In: PQS 2016. Berlin 2016. VolltextBIB DownloadDetails
• Metzger, Florian; Rafetseder, Albert; Schwartz, Christian; Hoßfeld, Tobias: Games and Frames: A Strange Tale of QoE Studies. In: 8th International Conference on Quality of Multimedia Experience (QoMEX 2016). Lisbon 2016. VolltextBIB DownloadDetails
• Seufert, Michael; Zach, Ondrej; Hoßfeld, Tobias; Slanina, Martin; Tran-Gia, Phuoc: Impact of Test Condition Selection in Adaptive Crowdsourcing Studies on Subjective Quality. In: 8th International Conference on Quality of Multimedia Experience (QoMEX 2016). Lisbon 2016. VolltextBIB DownloadDetails
• Sackl, Andreas; Schatz, Raimund; Hossfeld, Tobias; Metzger, Florian; Lister, David; Irmer, Ralf: QoE Management Made Uneasy: The Case of Cloud Gaming. In: IEEE ICC 2016. Kuala Lumpur 2016. VolltextBIB DownloadDetails
• Sieber, Christian; Heegaard, Poul; Hoßfeld, Tobias; Kellerer, Wolfgang: Sacrificing Efficiency for Quality of Experience: YouTube’s Redundant Traffic Behavior. IFIP Networking 2016, Vienna, Austria 2016. PDFBIB DownloadKurzfassungDetails

  Internet traffic reports show that YouTube is one of the major sources of data traffic world-wide. Furthermore, the data traffic shifts from mostly fixed landlines to cellular data connections where bandwidth is sparse and expensive. Previous studies revealed that YouTube uses a user-friendly HTTP Adaptive Streaming (HAS) strategy which sacrifices bandwidth efficiency to increase the average playback quality for the user. That way, it happens that the same video segment is transmitted in two or more quality levels, but only one can be shown to the user. We denote this as redundant traffic and this work is dedicated to understanding the influence factors on the amount of redundant traffic. This paper presents the results of a large-scale study with over 12,000 video views over a bottleneck link shaped to various bandwidths.We first evaluate the playback characteristics and show that YouTube’s HAS algorithm linearly increases the average playback quality with the available bandwidth while at the same time video buffering is sublinearly decreased. Furthermore, we identify video-dependent bandwidths which optimize the playback time on a quality level. Afterward, we show that this is achieved by discarding lower layer segments and therefore paid with redundant traffic of up to 40%. We evaluate the overall efficiency of the system and show that YouTube is able to improve the average quality level by up to 0.7 quality levels by using this adaptation strategy. However, a penalty of 0.5 quality levels is paid for it due to the discarded data of the lower quality segments.

• Wamser, Florian; Casas, Pedro; Seufert, Michael; Moldovan, Christian; Tran-Gia, Phuoc; Hoßfeld, Tobias: Modeling the YouTube Stack: from Packets to Quality of Experience. In: Computer Networks (2016). doi:10.1016/j.comnet.2016.03.020VolltextBIB DownloadKurzfassungDetails

  YouTube is one of the most popular and volume-dominant services in today’s Internet, and has changed the Web for ever. Consequently, network operators are forced to consider it in the design, deployment, and optimization of their networks. Taming YouTube requires a good understanding of the complete YouTube stack, from the network streaming service to the application itself. Understanding the interplays between individual YouTube functionalities and their implications for traffic and user Quality of Experience (QoE) becomes paramount nowadays. In this paper we characterize and model the YouTube stack at different layers, going from the generated network traffic to the QoE perceived by the users watching YouTube videos. Firstly, we present a network traffic model for the YouTube flow control mechanism, which permits to understand how YouTube provisions video traffic flows to users. Secondly, we investigate how traffic is consumed at the client side, deriving a simple model for the YouTube application. Thirdly, we analyze the implications for the end user, and present a model for the quality as perceived by them. This model is finally integrated into a system for real time QoE-based YouTube monitoring, highly useful to operators to assess the performance of their networks for provisioning YouTube videos. The central parameter for all the presented models is the buffer level at the YouTube application layer. This paper provides an extensive compendium of objective tools and models for network operators to better understand the YouTube traffic in their networks, to predict the playback behavior of the video player, and to assess how well they are doing in practice in delivering YouTube videos to their customers.

• Liotou, Eirini; Hoßfeld, Tobias; Moldovan, Christian; Metzger, Florian; Tsolkas, Dimitris; Passas, Nikos: Enriching HTTP Adaptive Streaming with Context Awareness - A Tunnel Case Study. In: CQRM - Communications QoS, Reliability and Modeling Symposium. ICC, 2016. VolltextBIB DownloadDetails
• Seufert, Michael; Griepentrog, Tobias; Burger, Valentin; Hoßfeld, Tobias: A Simple WiFi Hotspot Model for Cities. In: IEEE Communications Letters, Jg. 2016 (2016) Nr. 20, S. 384-387. doi:10.1109/LCOMM.2015.2509074VolltextBIB DownloadDetails
• Burger, Valentin; Seufert, Michael; Hoßfeld, Tobias; Tran-Gia, Phuoc: Performance evaluation of backhaul bandwidth aggregation using a partial sharing scheme. In: Physical Communication (2016). doi:10.1016/j.phycom.2016.01.005VolltextBIB DownloadKurzfassungDetails

  To cope with the increasing demand of mobile devices and the limited capacity of cellular networks mobile connections are offloaded to WiFi. The access capacity is further increased, by aggregating bandwidth of WiFi access links. To analyze the performance of aggregated access links we model the most simple case of two cooperating systems interchanging capacities using an offloading scheme. The resulting analytic model is computed by means of a two-dimensional birth and death process. It can be used to seamlessly evaluate the performance of systems between partitioning and complete sharing. This allows to optimize the setting of thresholds dependent on the load of the cooperating system. Furthermore the benefit of aggregating bandwidth in different scenarios with homogeneous and heterogeneous workloads is quantified and the performance of more than two cooperating systems is evaluated by simulation.

• Jarschel, Michael; Hoßfeld, Tobias; Davoli, Franco; Bolla, Raffaele; Bruschi, Roberto; Carrega, Alessandro: SDN-Enabled Energy-Efficient Network Management. In: Samdanis, Konstantinos; Rost, Peter; Maeder, Andreas; Meo, Michela; Verikoukis, Christos (Hrsg.): Green Communications: Principles, Concepts and Practice. John Wiley & Sons, 2015, S. 323-338. VolltextBIB DownloadDetails
• Hirth, Matthias; Hoßfeld, Tobias; Mellia, Marco; Schwartz, Christian; Lehrieder, Frank: Crowdsourced network measurements: Benefits and best practices. In: Elsevier Computer Networks, Jg. 2015 (2015) Nr. 90, S. 85-98. doi:Crowdsourced network measurements: Benefits and best practicesVolltextBIB DownloadDetails
• Seufert, Michael; Hoßfeld, Tobias; Sieber, Christian: Impact of Intermediate Layer on Quality of Experience of HTTP Adaptive Streaming.. In: 11th International Conference on Network and Service Management (CNSM). IEEE, Barcelona, Spain 2015. doi:10.1109/CNSM.2015.7367367VolltextBIB DownloadDetails
• Gardlo, Bruno; Egger, Sebastian; Hossfeld, Tobias: Do Scale-Design and Training Matter for Video QoE Assessments through Crowdsourcing?. In: Fourth International ACM Workshop on Crowdsourcing for Multimedia. Brisbane, Australia 2015. PDFBIB DownloadDetails
• Redi, Judith; Siahaan, Ernestasia; Korshunov, Pavel; Habigt, Julian; Hossfeld, Tobias: When the crowd challenges the lab: lessons learnt from subjective studies on image aesthetic appeal. In: Fourth International ACM Workshop on Crowdsourcing for Multimedia. Brisbane, Australia 2015. PDFBIB DownloadDetails
• Seufert, Michael; Schwind, Anika; Hoßfeld, Tobias; Tran-Gia, Phuoc: Analysis of Group-based Communication in WhatsApp. In: 7th EAI International Conference on Mobile Networks and Management. Santander, Spain 2015. VolltextBIB DownloadDetails
• Seufert, Michael; Lange, Stanislav; Hoßfeld, Tobias: More than topology: Joint topology and attribute sampling and generation of social network graphs. In: Elsevier Computer Communications, Jg. 2016 (2015) Nr. 73,B, S. 176-187. doi:10.1016/j.comcom.2015.07.023VolltextBIB DownloadDetails
• Seufert, Michael; Burger, Valentin; Wamser, Florian; Tran-Gia, Phuoc; Moldovan, Christian; Hoßfeld, Tobias: Utilizing Home Router Caches to Augment CDNs toward Information-Centric Networking. In: EuCNC 2015. Paris, France 2015. VolltextBIB DownloadDetails
• Hoßfeld, Tobias; Fiedler, Markus: The Unexpected QoE Killer: When the Network Emulator Misshapes Traffic and QoE. In: QoMEX 2015. Costa Navarino, Greece 2015. VolltextBIB DownloadDetails
• Hoßfeld, Tobias; Heegard, Poul; Varela, Martin: QoE beyond the MOS: Added Value Using Quantiles and Distributions. QoMEX 2015, Costa Navarino, Greece 2015. VolltextBIB DownloadDetails
• Hossfeld, Tobias; Skorin-Kapov, Lea; Haddad, Yoram; Pocta, Peter; Siris, Vasilios A.; Zgank, Andrej; Melvin, Hugh: Can context monitoring improve QoE? A case study of video flash crowds in the Internet of Services. In: QCMAN 2015 - Third IFIP/IEEE International Workshop on Quality of Experience Centric Management. Ottawa, Canada 2015. VolltextBIB DownloadDetails
• Varela, Martín; Skorin-Kapov, Lea; Mäki, Toni; Hoßfeld, Tobias: QoE in the Web: A Dance of Design and Performance. QoMEX 2015, Costa Navarino, Greece 2015. VolltextBIB DownloadDetails
• Hoßfeld, Tobias; Seufert, Michael; Sieber, Christian; Zinner, Thomas; Tran-Gia, Phuoc: Identifying QoE Optimal Adaptation of HTTP Adaptive Streaming Based on Subjective Studies. In: Elsevier Computer Networks, Jg. 2015 (2015) Nr. 81, S. 320-332. doi:10.1016/j.comnet.2015.02.015VolltextBIB DownloadKurzfassungDetails

  HTTP Adaptive Streaming (HAS) technologies, e.g., Apple HLS or MPEG-DASH, automatically adapt the delivered video quality to the available network. This reduces stalling of the video but additionally introduces quality switches, which also influence the user-perceived Quality of Experience (QoE). In this work, we conduct a subjective study to identify the impact of adaptation parameters on QoE. The results indicate that the video quality has to be maximized first, and that the number of quality switches is less important. Based on these results, a method to compute the optimal QoE-optimal adaptation strategy for HAS on a per user basis with mixed-integer linear programming is presented. This QoE-optimal adaptation enables the benchmarking of existing adaptation algorithms for any given network condition. Moreover, the investigated concept is extended to a multi-user IPTV scenario. The question is answered whether video quality, and thereby, the QoE can be shared in a fair manner among the involved users.

• Hoßfeld, Tobias; Moldovan, Christian; Schwartz, Christian: To Each According to his Needs: Dimensioning Video Buffer for Specific User Profiles and Behavior. In: QCMAN 2015. Ottawa, Canada 2015. PDFBIB DownloadDetails
• Seufert, M.; Egger, S.; Slanina, M.; Zinner, T.; Hossfeld, T.; Tran-Gia, P.: A Survey on Quality of Experience of HTTP Adaptive Streaming. In: IEEE Communications Surveys & Tutorials, Jg. 2014 (2014). doi:10.1109/COMST.2014.2360940VolltextBIB DownloadDetails
• Hoßfeld, T.; Hirth, M.; Redi, J.; Mazza, F.; Korshunov, P.; Naderi, B.; Seufert, M.; Gardlo, B.; Egger, S.; Keimel, C.: Best Practices and Recommendations for Crowdsourced QoE - Lessons learned from the Qualinet Task Force Crowdsourcing, Systems, European Network On Quality Of Experience In Multimedia; Services (Hrsg.), 2014. PDFVolltextBIB DownloadDetails
• Hoßfeld, Tobias; Seufert, Michael; Sieber, Christian; Zinner, Thomas; Tran-Gia, Phuoc: Close to Optimum? User-centric Evaluation of Adaptation Logics for HTTP Adaptive Streaming. In: PIK - Praxis der Informationsverarbeitung und Kommunikation, Jg. 2014 (2014). doi: 10.1515/pik-2014-0029VolltextBIB DownloadDetails
• Hoßfeld, T.; Keimel, C.; Timmerer, C.: Crowdsourcing Quality-of-Experience Assessments. In: IEEE Computer, Jg. 2014 (2014) Nr. 47, S. 98-102. doi:10.1109/MC.2014.245VolltextBIB DownloadDetails
• Seufert, Michael; Darzanos, George; Papafili, Ioanna; Lapacz, Roman; Burger, Valentin; Hoßfeld, Tobias: Socially-Aware Traffic Management. In: Zweig, Katharina; Neuser, Wolfgang; Pipek, Volkmar; Rohde, Markus; Scholtes, Ingo (Hrsg.): Socioinformatics - The Social Impact of Interactions between Humans and IT. Springer International Publishing, 2014, S. 25-43. VolltextBIB DownloadDetails
• Burger, Valentin; Hock, Davi; Scholtes, Ingo; Hoßfeld, Tobias; Garcia, David; Seufert, Michael: Social Network Analysis in the Enterprise: Challenges and Opportunities. In: Zweig, Katharina; Neuser, Wolfgang; Pipek, Volkmar; Rohde, Markus; Scholtes, Ingo (Hrsg.): Socioinformatics - The Social Impact of Interactions between Humans and IT. Springer International Publishing, 2014, S. 95-120. VolltextBIB DownloadDetails
• Hoßfeld, Tobias: On Training the Crowd for Subjective Quality Studies. In: VQEG eLetter, Jg. 1 (2014). VolltextBIB DownloadDetails
• Hoßfeld, Tobias; Timmerer, Christian: Quality of Experience Assessment using Crowdsourcing. In: IEEE COMSOC MMTC R-Letter, Jg. 5 (2014). VolltextBIB DownloadDetails
• Hoßfeld, Tobias; Burger, Valentin; Hinrichsen, Haye; Hirth, Matthias; Tran-Gia, Phuoc: On the computation of entropy production in stationary social networks. In: Social Network Analysis and Mining, Jg. 4 (2014). VolltextBIB DownloadDetails
• Hoßfeld, Tobias; Hirth, Matthias; Korshunov, Pavel; Hanhart, Philippe; Gardlo, Bruno; Keimel, Christian; Timmerer, Christian: Survey of Web-based Crowdsourcing Frameworks for Subjective Quality Assessment. In: 16th International Workshop on Multimedia Signal Processing. Jakarta, Indonesia 2014. VolltextBIB DownloadDetails
• Hossfeld, Tobias; Keimel, Christian; Hirth, Matthias; Gardlo, Bruno; Habigt, Julian; Diepold, Klaus; Tran-Gia, Phuoc: Best Practices for QoE Crowdtesting: QoE Assessment with Crowdsourcing. In: Transactions on Multimedia, Jg. 16 (2014). VolltextBIB DownloadDetails
• Hoßfeld, Tobias; Seufert, Michael; Sieber, Christian; Zinner, Thomas: Assessing Effect Sizes of Influence Factors Towards a QoE Model for HTTP Adaptive Streaming. In: 6th International Workshop on Quality of Multimedia Experience (QoMEX). Singapore 2014. VolltextBIB DownloadDetails
• Jarschel, Michael; Zinner, Thomas; Hoßfeld, Tobias; Tran-Gia, Phuoc; Kellerer; Wolfgang: Interfaces, Attributes, and Use Cases: A Compass for SDN. In: IEEE Communications Magazine, Jg. 52 (2014). VolltextBIB DownloadDetails
• Oechsner, Simon; Bellalta, Boris; Dimitrova, Desislava; Hoßfeld, Tobias: Visions and Challenges for Sensor Network Collaboration in the Cloud. In: The Eighth International Conference on Innovative Mobile and Internet Services in Ubiquitous Computing (IMIS-2014). Birmingham, UK 2014. BIB DownloadDetails
• Hirth, Matthias; Scheuring, Sven; Hoßfeld, Tobias; Schwartz, Christian; Tran-Gia, Phuoc: Predicting Result Quality in Crowdsourcing Using Application Layer Monitoring. In: 5th International Conference on Communications and Electronics (ICCE 2014). Da Nang, Vietnam 2014. VolltextBIB DownloadDetails
• Burger, Valentin; Hirth, Matthias; Schwartz, Christian; Hoßfeld, Tobias: Increasing the Coverage of Vantage Points in Distributed Active Network Measurements by Crowdsourcing. In: Measurement, Modelling and Evaluation of Computing Systems (MMB 2014). Bamberg, Germany 2014. VolltextBIB DownloadDetails
• Hoßfeld, Tobias; Keimel, Christian: Crowdsourcing in QoE Evaluation. In: Sebastian Möller, Alexander Raake (Hrsg) (Hrsg.): Quality of Experience: Advanced Concepts, Applications and Methods. Springer: T-Labs Series in Telecommunication Services, ISBN 978-3-319-02680-0, 2014. VolltextBIB DownloadDetails
• Hoßfeld, Tobias; Schatz, Raimund; Krieger, Udo: QoE of YouTube Video Streaming for Current Internet Transport Protocols. In: Measurement, Modelling and Evaluation of Computing Systems (MMB 2014). Bamberg, Germany 2014. VolltextBIB DownloadDetails
• Metzger, Florian; Schwartz, Christian; Hoßfeld, Tobias: GTP-based Load Model and Virtualization Gain for a Mobile Network’s GGSN. In: 5th International Conference on Communications and Electronics. Da Nang, Vietnam 2014. VolltextBIB DownloadDetails
• Zinner, Thomas; Hoßfeld, Tobias; Fiedler, Markus; Liers, Florian; Volkert, Thomas; Khondoker, Rahamatullah; Schatz, Raimund: Requirement Driven Prospects for Realizing User-Centric Network Orchestration. In: Multimedia Tools and Applications, doi: 10.1007/s11042-014-2072-5 (2014). VolltextBIB DownloadDetails
• Strohmeier, Dominik; Egger, Sebastian; Raake, Alexander; Schatz, Raimund; Hoßfeld, Tobias: Web Browsing. In: Sebastian Möller, Alexander Raake (Hrsg) (Hrsg.): Quality of Experience: Advanced Concepts, Applications and Methods. Springer: T-Labs Series in Telecommunication Services, ISBN 978-3-319-02680-0, 2014. VolltextBIB DownloadDetails
• Schwartz, Christian; Hirth, Matthias; Hoßfeld, Tobias; Tran-Gia, Phuoc: Performance Model for Waiting Times in Cloud File Synchronization Services. In: 26th International Teletraffic Congress (ITC). Karlskrona, Sweden 2014. VolltextBIB DownloadDetails
• Wajda, Krzysztof; Stankiewicz, Rafal; Dulinski, Zbigniew; Hoßfeld, Tobias; Seufert, Michael; Hausheer, David; Wichtlhuber, Matthias; Papafili, Ioanna; Dramitinos, Manos; Cruschelli, Paolo; Soursos, Sergios; Lapacz, Roman; Stiller, Burkhard: Socially-aware Management of New Overlay Applications Traffic - The Optimization Potentials of the SmartenIT Approach. In: 6th International Conference on Mobile Networks and Management (MONAMI). Würzburg, Germany 2014. VolltextBIB DownloadDetails
• Burger, Valentin; Hoßfeld, Tobias; Garcia, David; Seufert, Michael; Scholtes, Ingo; Hock, David: Resilience in Enterprise Social Networks. In: Workshop Sozioinformatik 2013. Koblenz, Germany 2013. VolltextBIB DownloadDetails
• Hausheer, David; Hoßfeld, Tobias (Hrsg) (Hrsg.): Proceedings of the Social-aware Economic Traffic Management for Overlay and Cloud Applications Workshop (SETM 2013), CNSM Workshop 2013, Zürich, Switzerland 2013. VolltextBIB DownloadDetails
• Seufert, Michael; Darzanos, George; Burger, Valentin; Papafili, Ioanna; Hoßfeld, Tobias: Socially-Aware Traffic Management. In: Workshop Sozioinformatik 2013. Koblenz, Germany 2013. VolltextBIB DownloadDetails
• Hofeld, Tobias; Tran-Gia, Phuoc: Int. J. of Communication Networks and Distributed Systems. BIB DownloadDetails
• Redi, Judith; Hossfeld, Tobias; Korshunov, Pavel; Mazza, Filippo; Povoa, Isabel; Keimel, Christian: Crowdsourcing-based multimedia subjective evaluations: a case study on image recognizability and aesthetic appeal. In: ACM CrowdMM 2013. Barcelona, Spain 2013. VolltextBIB DownloadDetails
• Hoßfeld, Tobias; Tran-Gia, Phuoc; Vukovic, Maja (Hrsg.): Crowdsourcing: From Theory to Practice and Long-Term Perspectives - Report of the Dagstuhl Seminar 13361, Schloss Dagstuhl--Leibniz-Zentrum fuer Informatik, Dagstuhl, Germany 2013. VolltextBIB DownloadKurzfassungDetails

  This report documents the program and the outcomes of Dagstuhl Seminar 13361 "Crowdsourcing: From Theory to Practice and Long-Term Perspectives". Crowdsourcing is a newly emerging service platform and business model in the Internet. In contrast to outsourcing, where a job is performed by a designated worker or employee, crowdsourcing means to outsource a job to a large, anonymous crowd of workers, the so-called human cloud, in the form of an open call. Current research in crowdsourcing addresses the following issues: crowdsourcing as a novel methodology for user-centered research; development of new services and applications based on human sensing, computation, and problem solving; engineering of improved crowdsourcing platforms including quality control mechanisms; incentive design and gamification of work; usage of crowdsourcing for professional business; theoretical frameworks for evaluation. The topic on crowdsourcing may have a huge impact on the Internet and its technical infrastructure, on society, and the future of work. In short, crowdsourcing will be a guiding paradigm and form the evolution of work in the next years. Therefore, this seminar helps coordinating research efforts in the different communities. In five presentation and discussion sessions, the diverse aspects of crowdsourcing were elaborated. The topics of the sessions covered (S1) crowdsourcing in general, (S2) industry use cases, (S3) crowdsourcing design and engineering, (S4) programming and implementing crowdsourcing, (S5) applications of crowdsourcing. The major interests of the seminar participants were then focused in four different working groups on (W1) long-term perspectives & impact on economics in five years, (W2) theory -- taxonomy and dimensions of crowdsourcing, (W3) industry use cases, (W4) crowdsourcing mechanisms and design. In parallel to this seminar, a topically related seminar on "Cloud-based Software Crowdsouring", organized by Michael N. Huhns, Wei Li, Martin Schader and Wei-Tek Tsal,(Dagstuhl Seminar 13362) took place. Therefore, a joint late night session was organized to discuss crowdsourcing with respect to ethics and its relation to social computation.

• Schatz, Raimund; Hoßfeld, Tobias (Hrsg) (Hrsg.): Proceedings of The Fourth Workshop on Perceptual Quality of Systems (PQS 2013), FTW, Vienna, Austria 2013. BIB DownloadDetails
• Sieber, Christian; Hoßfeld, Tobias; Zinner, Thomas; Tran-Gia, Phuoc; Timmerer, Christian: Implementation and User-centric Comparison of a Novel Adaptation Logic for DASH with SVC. In: IFIP/IEEE International Workshop on Quality of Experience Centric Management (QCMan). Ghent, Belgium 2013. VolltextBIB DownloadDetails
• Hinrichsen, Haye; Hoßfeld, Tobias; Hirth, Matthias; Tran-Gia, Phuoc: Entropy Production in Stationary Social Networks. In: 4th Workshop on Complex Networks (CompleNet 2013). Berlin, Germany 2013. VolltextBIB DownloadDetails
• Seufert, Michael; Lorey, Karl; Hirth, Matthias; Hoßfeld, Tobias: Gamification Framework for Personalized Surveys on Relationships in Online Social Networks. In: 1st International Workshop on Crowdsourcing and Gamification in the Cloud (CGCloud). Dresden, Germany 2013. VolltextBIB DownloadDetails
• Seufert, Michael; Burger, Valentin; Hoßfeld, Tobias: HORST - Home Router Sharing based on Trust. In: Workshop on Social-aware Economic Traffic Management for Overlay and Cloud Applications (SETM 2013). Zurich, Switzerland 2013. VolltextBIB DownloadDetails
• Schwartz, Christian; Scheib, Marc; Hoßfeld, Tobias; Tran-Gia, Phuoc; Gimenez-Guzman, Jose Manuel: Trade-Offs for Video-Providers in LTE Networks: Smartphone Energy Consumption Vs Wasted Traffic. In: 22nd International Teletraffic Congress Specialist Seminar on Energy Efficient and Green Networking. Christchurch, New Zealand 2013. VolltextBIB DownloadDetails
• Schwartz, Christian; Lehrieder, Frank; Wamser, Florian; Hoßfeld, Tobias; Tran-Gia, Phuoc: Smart-Phone Energy Consumption Vs. 3G Signaling Load: The Influence of Application Traffic Patterns. In: Tyrrhenian International Workshop 2013 on Digital Communications: Green ICT. Genova, Italy 2013. VolltextBIB DownloadDetails
• Schwartz, Christian; Hossfeld, Tobias; Lehrieder, Frank; Tran-Gia, Phuoc: Angry Apps: When Smartphone Users and Mobile Operators Get Annoyed. In: Journal of Computer Networks and Communications, Jg. 176217 (2013). VolltextBIB DownloadDetails
• Zinner, Thomas; Hossfeld, Tobias; Tran-Gia, Phuoc; Kellerer, Wolfgang: Software defined Networks - Das Internet flexibler gestalten und dynamischer steuern. In: ITG Mitgliederbeilage / VDE dialog (invited article) (2013). VolltextBIB DownloadDetails
• Varela, Martin; Mäki, Toni; Skorin-Kapov, Lea; Hoßfeld, Tobias: Towards an understanding of visual appeal in website design. In: Fifth International Workshop on Quality of Multimedia Experience (QoMEX 2013). Klagenfurt, Austria 2013. VolltextBIB DownloadDetails
• Sackl, Andreas; Seufert, Michael; Hoßfeld, Tobias: Asking Costs Little? The Impact of Tasks in Video QoE Studies on User Behavior and User Ratings. In: 4th International Workshop on Perceptual Quality of Systems (PQS 2013). Vienna, Austria 2013. VolltextBIB DownloadDetails
• Stiller, Burkhard; Hausheer, David; Hoßfeld, Tobias: Towards a Socially-Aware Management of New Overlay Application Traffic Combined with Energy Efficiency in the Internet (SmartenIT). In: Alex Galis, Anastasius Gavras (Hrsg) (Hrsg.): The Future Internet. Springer, LNCS 7858, 2013. VolltextBIB DownloadDetails
• Hoßfeld, Tobias; Strohmeier, Dominik; Raake, Alexander; Schatz, Raimund: Pippi Longstocking Calculus for Temporal Stimuli Pattern on YouTube QoE. In: 5th ACM Workshop on Mobile Video (MoVid 2013). Oslo, Norway 2013. VolltextBIB DownloadDetails
• Hoßfeld, Tobias; Schatz, Raimund; Biersack, Ernst; Plissonneau, Louis: Internet Video Delivery in YouTube: From Traffic Measurements to Quality of Experience. In: Biersack, Ernst; Callegari, Christian; Matijasevic, Maja (Hrsg) (Hrsg.): Data Traffic Monitoring and Analysis: From measurement, classification and anomaly detection to Quality of experience. Springer, 2013. VolltextBIB DownloadDetails
• Hoßfeld, Tobias; Hirth, Matthias; Tran-Gia, Phuoc: Crowdsourcing - Modell einer neuen Arbeitswelt im Internet. In: Informatik Spektrum, Wirtschaftsinformatik & Management, Jg. 5 (2013). VolltextBIB DownloadDetails
• Amrehn, Philipp; Vandenbroucke, Karel; Hoßfeld, Tobias; Moor, Katrien de; Hirth, Matthias; Schatz, Raimund; Casas, Pedro: Need for Speed? On Quality of Experience for File Storage Services. In: 4th International Workshop on Perceptual Quality of Systems (PQS 2013). Vienna, Austria 2013. VolltextBIB DownloadDetails
• Casas, Pedro; Schatz, Raimund; Hoßfeld, Tobias: Monitoring YouTube QoE: Is Your Mobile Network Delivering the Right Experience to your Customers?. In: IEEE Wireless Communications and Networking Conference (WCNC 2013). Shanghai, China 2013. VolltextBIB DownloadDetails
• Schatz, Raimund; Hoßfeld, Tobias; Janowski, Lucjan; Egger, Sebastian: From Packets to People: Quality of Experience as New Measurement Challenge. In: Biersack, Ernst; Callegari, Christian; Matijasevic, Maja (Hrsg) (Hrsg.): Data Traffic Monitoring and Analysis: From measurement, classification and anomaly detection to Quality of experience. Springer, 2013. VolltextBIB DownloadDetails
• Tran-Gia, Phuoc; Hoßfeld, Tobias; Hartmann, Matthias; Hirth, Matthias: Crowdsourcing and its Impact on Future Internet Usage. In: it - Information Technology, Jg. 55 (2013). VolltextBIB DownloadDetails
• Varela, Martin; Mäki, Toni; Skorin-Kapov, Lea; Hoßfeld, Tobias: Increasing Payments in Crowdsourcing: Don’t look a gift horse in the mouth. In: 4th International Workshop on Perceptual Quality of Systems (PQS 2013). Vienna, Austria 2013. VolltextBIB DownloadDetails
• Hofeld, Tobias; Schatz, Raimund: Quality of Experience of YouTube Video Streaming for Current Internet Transport Protocols. In: Computer Networks (2012). BIB DownloadDetails
• Schwartz, Christian; Hofeld, Tobias; Lehrieder, Frank; Tran-Gia, Phuoc: Angry Apps: When Smartphone Users and Mobile Operators Get Annoyed. In: Journal of Computer Networks and Communications (JCNC): Special Issue on “Improving QoS and QoE for Mobile Communications” (2012). VolltextBIB DownloadDetails
• Hoßfeld, Tobias; Hirth, Matthias; Tran-Gia, Phuoc: Aktuelles Schlagwort: Crowdsourcing. In: Informatik Spektrum, Jg. 35 (2012) Nr. 3. VolltextBIB DownloadDetails
• Gardlo, Bruno; Ries, Michal; Hoßfeld, Tobias: Impact of Screening Technique on Crowdsourcing QoE Assessments. In: 22nd International Conference Radioelektronika 2012, Special Session on Quality in multimedia systems. Brno, Czech Republic 2012. VolltextBIB DownloadDetails
• Egger, Sebastian; Reichl, Peter; Hoßfeld, Tobias; Schatz, Raimund: Time is Bandwidth? Narrowing the Gap between Subjective Time Perception and Quality of Experience. In: 2012 IEEE International Conference on Communications (ICC 2012). Ottawa, Canada 2012. VolltextBIB DownloadDetails
• Hoßfeld, Tobias; Schatz, Raimund; Varela, Martin; Timmerer, Christian: Challenges of QoE Management for Cloud Applications. In: IEEE Communications Magazine, Jg. 50 (2012) Nr. 4. VolltextBIB DownloadDetails
• Hoßfeld, Tobias; Liers, Florian; Schatz, Raimund; Staehle, Barbara; Staehle, Dirk; Volkert, Thomas; Wamser, Florian: Quality of Experience Management for YouTube: Clouds, FoG and the AquareYoum. In: PIK - Praxis der Informationverarbeitung und -kommunikation (PIK), Jg. 35 (2012) Nr. 3. VolltextBIB DownloadDetails
• Hofeld, Tobias; Zinner, Thomas; Fiedler, Markus; Liers, Florian; Volkert, Thomas; Khondoker, Rahamatullah; Schatz, Raimund: Requirement Driven Prospects for Realizing User-Centric Network Orchestration. In: Computer Communications Journal Special Issue on Human-Centric Multimedia Networking (2012). VolltextBIB DownloadDetails
• Zinner, Thomas; Klein, Dominik; Hoßfeld, Tobias: User-Centric Network-Application Interaction for Live HD Video Streaming. In: 4th International Conference on Mobile Networks and Management (MONAMI 2012). Hamburg, Germany 2012. VolltextBIB DownloadDetails
• Egger, Sebastian; Hoßfeld, Tobias; Schatz, Raimund; Fiedler, Markus: Waiting Times in Quality of Experience for Web Based Services. In: QoMEX 2012. Yarra Valley, Australia 2012. VolltextBIB DownloadDetails
• Ciszkowski, Tomasz; Mazurczyk, Wojciech; Kotulski, Zbigniew; Hoßfeld, Tobias; Fiedler, Markus; Collange, Denis: Towards Quality of Experience-based Reputation Models for Future Web Service Provisioning. In: Special Issue of the Springer Telecommunication Systems Journal: Future Internet Services and Architectures - Trends and Visions, Jg. 51 (2012). VolltextBIB DownloadDetails
• Burger, Valentin; Lehrieder, Frank; Hoßfeld, Tobias; Seedorf, Jan: Who Profits from Peer-to-Peer File-Sharing? Traffic Optimization Potential in BitTorrent Swarms. In: International Teletraffic Congress (ITC 24). Krakow, Poland 2012. VolltextBIB DownloadDetails
• Lehrieder, Frank; Dán, György; Hoßfeld, Tobias; Oechsner, Simon; Singeorzan, Vlad: Caching for BitTorrent-like P2P Systems: A Simple Fluid Model and its Implications. In: IEEE/ACM Transactions on Networking (TON), Jg. 20 (2012) Nr. 4. VolltextBIB DownloadDetails
• Hirth, Matthias; Hossfeld, Tobias; Tran-Gia, Phuoc: Analyzing Costs and Accuracy of Validation Mechanisms for Crowdsourcing Platforms. In: Mathematical and Computer Modelling (Elsevier) (2012). VolltextBIB DownloadDetails
• Gardlo, Bruno; Ries, Michal; Hoßfeld, Tobias; Schatz, Raimund: Microworkers vs. Facebook: The Impact of Crowdsourcing Platform Choice on Experimental Results. In: QoMEX 2012. Yarra Valley, Australia 2012. VolltextBIB DownloadDetails
• Jarschel, Michael; Schlosser, Daniel; Scheuring, Sven; Hoßfeld, Tobias: Gaming in the clouds: QoE and the users’ perspective. In: Mathematical and Computer Modelling (Elsevier) (2012). VolltextBIB DownloadDetails
• Zinner, Thomas; Liers, Florian; Hoßfeld, Tobias; Rauscher, Dirk; Reuther, Bernd; Günther, Daniel; Volkert, Thomas; Fiedler, Markus: Prospects for Realizing User-Centric Network Orchestration: FEC-protected SVC Streaming. In: 7. GI/ITG KuVS Fachgespräch ’Future Internet’. München, Germany 2012. VolltextBIB DownloadDetails
• Hirth, Matthias; Lehrieder, Frank; Oberste-Vorth, Stephan; Hoßfeld, Tobias; Tran-Gia, Phuoc: Wikipedia and its Network of Authors from a Social Network Perspective. In: International Conference on Communications and Electronics (ICCE). Hue, Vietnam 2012. VolltextBIB DownloadDetails
• Hoßfeld, Tobias; Egger, Sebastian; Schatz, Raimund; Fiedler, Markus; Masuch, Kathrin; Lorentzen, Charlott: Initial Delay vs. Interruptions: Between the Devil and the Deep Blue Sea. In: QoMEX 2012. Yarra Valley, Australia 2012. VolltextBIB DownloadDetails
• Schatz, Raimund; Hoßfeld, Tobias; Casas, Pedro: Passive YouTube QoE Monitoring for ISPs. In: Best Paper Award at Workshop on Future Internet and Next Generation Networks (FINGNet-2012). Palermo, Italy 2012. VolltextBIB DownloadDetails
• Lehrieder, Frank; Oechsner, Simon; Hoßfeld, Tobias; Staehle, Dirk; Despotovic, Zoran; Kellerer, Wolfgang; Michel, Maximilian: Mitigating Unfairness in Locality-Aware Peer-to-Peer Networks. In: International Journal of Network Management (IJNM), Special Issue on Economic Traffic Management, Jg. 21 (2011) Nr. 1. VolltextBIB DownloadDetails
• Jarschel, Michael; Schlosser, Daniel; Scheuring, Sven; Hoßfeld, Tobias: An Evaluation of QoE in Cloud Gaming Based on Subjective Tests. In: Workshop on Future Internet and Next Generation Networks (FINGNet-2011). Seoul, Korea 2011. VolltextBIB DownloadDetails
• Hoßfeld, Tobias; Schatz, Raimund; Egger, Sebastian: SOS: The MOS is not enough!. In: QoMEX 2011. Mechelen, Belgium 2011. VolltextBIB DownloadDetails
• Fiedler, Markus; Hoßfeld, Tobias; Norros, Ilkka; Rodrigues, Joel; Pereira, Paulo Rogério: The Network of Excellence Euro-NF and its Specific Joint Research Projects. In: ICST Global Community Magazine (2011). BIB DownloadDetails
• Hoßfeld, Tobias; Tran-Gia, Phuoc: EuroView 2010: Visions of Future Generation Networks. In: ACM SIGCOMM Computer Communications Review CCR, Jg. 41 (2011) Nr. 3. VolltextBIB DownloadDetails
• Hoßfeld, Tobias; Schatz, Raimund; Seufert, Michael; Hirth, Matthias; Zinner, Thomas; Tran-Gia, Phuoc: Quantification of YouTube QoE via Crowdsourcing. In: IEEE International Workshop on Multimedia Quality of Experience - Modeling, Evaluation, and Directions (MQoE 2011). Dana Point, CA, USA 2011. VolltextBIB DownloadDetails
• Hirth, Matthias; Hoßfeld, Tobias; Tran-Gia, Phuoc: Anatomy of a Crowdsourcing Platform - Using the Example of Microworkers.com. In: Workshop on Future Internet and Next Generation Networks (FINGNet). Seoul, Korea 2011. VolltextBIB DownloadDetails
• Hoßfeld, Tobias; Schatz, Raimund; Biedermann, Sebastian; Platzer, Alexander; Egger, Sebastian; Fiedler, Markus: The Memory Effect and Its Implications on Web QoE Modeling. In: 23rd International Teletraffic Congress (ITC 23). San Francisco, USA 2011. VolltextBIB DownloadDetails
• Hoßfeld, Tobias; Liers, Florian; Volkert, Thomas; Schatz, Raimund: FoG and Clouds: Optimizing QoE for YouTube. In: KuVS 5thGI/ITG KuVS Fachgespräch NG Service Delivery Platforms. Munich, Germany 2011. VolltextBIB DownloadDetails
• Hoßfeld, Tobias; Fiedler, Markus; Zinner, Thomas: The QoE Provisioning-Delivery-Hysteresis and Its Importance for Service Provisioning in the Future Internet. In: Proceedings of the 7th Conference on Next Generation Internet Networks (NGI). Kaiserslautern, Germany 2011. VolltextBIB DownloadDetails
• Hoßfeld, Tobias: Aktuelle Entwicklungen im Internet und sich daraus ergebende rechtliche Fragestellungen. In: Herczeg, Jiri; Grivna, Tomas (Hrsg) (Hrsg.): Internet-Kriminalität und die neuen Herausforderungen der Informationsgesellschaft des 21. Jahrhundert. Wolters Kluwer CR, 2011. VolltextBIB DownloadDetails
• Dan, György; Hoßfeld, Tobias; Oechsner, Simon; Cholda, Piotr; Stankiewicz, Rafal; Papafili, Ioanna; Stamoulis, George D.: Interaction Patterns between P2P Content Distribution Systems and ISPs. In: IEEE Communications Magazine, Jg. 49 (2011) Nr. 5. VolltextBIB DownloadDetails
• Hoßfeld, Tobias; Lehrieder, Frank; Hock, David; Oechsner, Simon; Despoto-vic, Zoran; Kellerer, Wolfgang; Michel, Maximilian: Characterization of BitTorrent Swarms and their Distribution in the Internet. In: Computer Networks, Jg. 55 (2011) Nr. 5. VolltextBIB DownloadDetails
• Hoßfeld, Tobias; Hirth, Matthias; Tran-Gia, Phuoc: Modeling of Crowdsourcing Platforms and Granularity of Work Organization in Future Internet. In: International Teletraffic Congress (ITC 23). San Francisco, USA 2011. VolltextBIB DownloadDetails
• Hirth, Matthias; Hoßfeld, Tobias; Tran-Gia, Phuoc: Cost-Optimal Validation Mechanisms and Cheat-Detection for Crowdsourcing Platforms. In: Workshop on Future Internet and Next Generation Networks (FINGNet). Seoul, Korea 2011. VolltextBIB DownloadDetails
• Stankiewicz, Rafal; Cholda, Piotr; Domzal, Jerzy; Wojcik, Robert; Hoßfeld, Tobias; Zinner, Thomas; Oechsner, Simon; Lehrieder, Frank: Influence of traffic management solutions on Quality of Experience for prevailing overlay applications. In: Proceedings of the 7th Conference on Next Generation Internet Networks (NGI). Kaiserslautern, Germany 2011. VolltextBIB DownloadDetails
• Meier, Sebastian; Barisch, Marc; Kirstädter, Andreas; Schlosser, Daniel; Duelli, Michael; Jarschel, Michael; Hoßfeld, Tobias; Hoffmann, Klaus; Hoffmann, Marco; Kellerer, Wolfgang; Khan, Ashiq; Jurca, Dan; Kozu, Kazuyuki: Provisioning and Operation of Virtual Networks. In: Electronic Communications of the EASST, Kommunikation in Verteilten Systemen 2011, Jg. 37 (2011). VolltextBIB DownloadDetails
• Lehrieder, Frank; Dán, György; Hoßfeld, Tobias; Oechsner, Simon; Singeorzan, Vlad: The Impact of Caching on BitTorrent-like Peer-to-peer Systems. In: 10th IEEE International Conference on Peer-to-Peer Computing 2010 - IEEE P2P 2010. Best Paper Award, Delft, the Netherlands 2010. VolltextBIB DownloadDetails
• Oechsner, Simon; Zinner, Thomas; Prokopetz, Jochen; Hoßfeld, Tobias: Supporting Scalable Video Codecs in a P2P Video-on-Demand Streaming System. In: 21th ITC Specialist Seminar on Multimedia Applications - Traffic, Performance and QoE. Miyazaki, Jap 2010. VolltextBIB DownloadDetails
• Lehrieder, Frank; Oechsner, Simon; Hoßfeld, Tobias; Despotovic, Zoran; Kellerer, Wolfgang; Michel, Maximilian: Can P2P-Users Benefit from Locality-Awareness?. In: 10th IEEE International Conference on Peer-to-Peer Computing 2010 - IEEE P2P 2010. Best Paper Award, Delft, the Netherlands 2010. VolltextBIB DownloadDetails
• Stiller, Burkhard; Hoßfeld, Tobias; Stamoulis, George D. (Hrsg) (Hrsg.): Incentives, Overlays, and Economic Traffic Control, Springer, Amsterdam, The Netherlands 2010. BIB DownloadDetails
• Schlosser, Daniel; Jarschel, Michael; Duelli, Michael; Hoßfeld, Tobias; Hoffmann, Klaus; Hoffmann, Marco; Morper, Hans Jochen; Jurca, Dan; Khan, Ashiq: A Use Case Driven Approach to Network Virtualization. In: accepted at IEEE Kaleidoscope 2010, published via OPUS Würzburg under OpenAccess. Würzburg, Germany 2010. VolltextBIB DownloadDetails
• Schlosser, D.; Hoffmann, M.; Hoßfeld, T.; Jarschel, M.; Kirstaedter, A.; Kellerer, W.; Köhler, S.: COMCON: Use Cases for Virtual Future Networks. In: TridentCom 2010. Berlin 2010. VolltextBIB DownloadDetails
• Fiedler, Markus; Hoßfeld, Tobias; Tran-Gia, Phuoc: A Generic Quantitative Relationship between Quality of Experience and Quality of Service. In: IEEE Network: The Magazine of Global Internetworking, Jg. 24 (2010) Nr. 2. VolltextBIB DownloadDetails
• Fiedler, Markus; Hoßfeld, Tobias: Quality of Experience-Related Differential Equations and Provisioning-Delivery Hysteresis. In: to 21st ITC Specialist Seminar on Multimedia Applications - Traffic, Performance and QoE. Phoenix Seagaia Resort, Miyazaki, Japan 2010. VolltextBIB DownloadDetails
• Chołda, Piotr; Domzał, Jerzy; Wójcik, Robert; Stankiewicz, Rafał; Lehrieder, Frank; Hoßfeld, Tobias; Oechsner, Simon; Singeorzan, Vlad: Performance Evaluation of P2P Caches: Flash-Crowd Case. In: Australasian Telecommunication Networks and Applications Conference (ATNAC) 2010. Auckland, New Zealand 2010. VolltextBIB DownloadDetails
• Zinner, Thomas; Hoßfeld, Tobias; Minash, Tahir Nawaz; Fiedler, Markus: Controlled vs. Uncontrolled Degradations of QoE - The Provisioning-Delivery Hysteresis in Case of Video. In: New Dimensions in the Assessment and Support of Quality of Experience (QoE) for Multimedia Applications. Tampere 2010. VolltextBIB DownloadDetails
• Zinner, Thomas; Hohlfeld, Oliver; Abboud, Osama; Hoßfeld, Tobias: Impact of Frame Rate and Resolution on Objective QoE Metrics. In: International Workshop on Quality of Multimedia Experience, 2010. Trondheim 2010. VolltextBIB DownloadDetails
• Zinner, Thomas; Abboud, Osama; Hohlfeld, Oliver; Hoßfeld, Tobias; Tran-Gia, Phuoc: Towards QoE Management for Scalable Video Streaming. In: 21th ITC Specialist Seminar on Multimedia Applications - Traffic, Performance and QoE. Miyazaki, Jap 2010. VolltextBIB DownloadDetails
• Berl, Andreas; Meer, Hermann de; Hoßfeld, Tobias: P2P Solutions for Cellular Networks. In: International Conference on Advances in P2P Systems (AP2PS 2009). Sliema, Malta 2009. VolltextBIB DownloadDetails
• Hoßfeld, Tobias; Duelli, Michael; Staehle, Dirk; Tran-Gia, Phuoc: Chapter VIII: Cooperation Strategies for P2P Content Distribution in Cellular Mobile Networks: Considering Mobility and Heterogeneity. In: Seet, Boon-Chong (Hrsg) (Hrsg.): Mobile Peer-to-Peer Computing for Next Generation Distributed Environments: Advancing Conceptual and Algorithmic Applications. IGI Global, 2009, S. 1234-1234. VolltextBIB DownloadDetails
• Ciszkowski, Tomasz; Mazurczyk, Wojciech; Kotulski, Zbigniew; Hoßfeld, Tobias; Fiedler, Markus; Collange, Denis: Towards Quality of Experience-based Reputation Models for Future Web Service Provisioning. In: Future Internet Architectures: New Trends in Service Architectures (2nd Euro-NF Workshop). Santander, Spain 2009. VolltextBIB DownloadDetails
• Schlosser, Daniel; Hoßfeld, Tobias: Service Oriented Network Framework Enabling Global QoS and Network Virtualization. In: ITC SS 2009. Hoi An 2009. VolltextBIB DownloadDetails
• Schlosser, Daniel; Hoßfeld, Tobias: Mastering Selfishness and Heterogeneity in Mobile P2P Content Distribution Networks with Multiple Source Download in Cellular Networks. In: Peer-to-Peer Networking and Applications, Special Issue on Mobile P2P Networking and Computing, Jg. 2 (2009) Nr. 3. VolltextBIB DownloadDetails
• Oechsner, Simon; Lehrieder, Frank; Hoßfeld, Tobias; Metzger, Florian; Pussep, Konstantin; Staehle, Dirk: Pushing the Performance of Biased Neighbor Selection through Biased Unchoking. In: 9th International Conference on Peer-to-Peer Computing. Seattle, USA 2009. VolltextBIB DownloadDetails
• Oechsner, Simon; Hoßfeld, Tobias; Tran-Gia, Phuoc: Performance Evaluation of a Distributed Lookup System for a Virtual Database Server. In: 20th ITC Specialist Seminar. Hoi An, Vietnam 2009. VolltextBIB DownloadDetails
• Hung, Nguyen Chan; Hoßfeld, Tobias; Hoang, Giang Ngo; Vinh, Vu Thanh; Thang, Nguyen Manh: Challenges in the Development of Mobile P2P Applications and Services. In: Vietname Journal on Information and Communication Technologies (2009) Nr. 2. VolltextBIB DownloadDetails
• Hoßfeld, Tobias; Schlosser, Daniel; Tutschku, Kurt; Tran-Gia, Phuoc: Chapter VII: Cooperation Strategies for P2P Content Distribution in Cellular Mobile Networks: Considering Selfishness and Heterogeneity. In: Seet, Boon-Chong (Hrsg) (Hrsg.): Mobile Peer-to-Peer Computing for Next Generation Distributed Environments: Advancing Conceptual and Algorithmic Applications. IGI Global, 2009. VolltextBIB DownloadDetails
• Hoßfeld, Tobias; Leibnitz, Kenji; Nakao, Akihiro: Modeling of Modern Router Architectures Supporting Network Virtualization. In: 2nd International Workshop on the Network of the Future (FutureNet II) in conjunction with IEEE GLOBECOM 2009. Honolulu, Hawaii 2009. VolltextBIB DownloadDetails
• Hoßfeld, Tobias; Hausheer, David; Hecht, Fabio; Lehrieder, Frank; Oechsner, Simon; Papafili, Ioanna; Racz, Peter; Soursos, Sergios; Staehle, Dirk; Stamoulis, George D.; Tran-Gia, Phuoc; Stiller, Burkhard: An Economic Traffic Management Approach to Enable the TripleWin for Users, ISPs, and Overlay Providers. In: Tselentis, Georgios; Domingue, John; Galis, Alex; Gavras, Anastasius; Hausheer, David; Krco, Srdjan; Lotz, Volkmar; Zahariadis, Theodore (Hrsg) (Hrsg.): FIA Prague Book. IOS Press Books Online, Towards the Future Internet - A European Research Perspective 2009, S. 24-24. VolltextBIB DownloadDetails
• Stiller, Burkhard; Hausheer, David; Hoßfeld, Tobias; Liotta, Antonio; Spirou, Spiros; Waldburger, Martin: A Discussion of Socio-economic Management and Incentives for the Future Internet. In: 2nd International Workshop on the Network of the Future (FutureNet II) in conjunction with IEEE GLOBECOM 2009. Honolulu, Hawaii 2009. VolltextBIB DownloadDetails
• Tran-Gia, Phuoc; Hoßfeld, Tobias; Menth, Michael; Pries, Rastin: Emerging Issues in Current Future Internet Design. In: e&i Elektrotechnik und Informationstechnik, Special Issue ’Future Internet’, ISSN: 0932-383X (print), ISSN: 1613-7620 (online), Jg. 126 (2009) Nr. 7-8. VolltextBIB DownloadDetails
• Tutschku, Kurt; Berl, Andreas; Hoßfeld, Tobias; Meer, Hermann de: Chapter XVI: Mobile P2P in Cellular Mobile Networks: Architecture and Performance. In: Seet, Boon-Chong (Hrsg) (Hrsg.): Mobile Peer-to-Peer Computing for Next Generation Distributed Environments: Advancing Conceptual and Algorithmic Applications. IGI Global, 2009. VolltextBIB DownloadDetails
• Binzenhöfer, Andreas; Hoßfeld, Tobias; Kunzmann, Gerald; Eger, Kolja: Efficient Simulation of Large-Scale P2P Networks. In: International Journal of Computational Science and Engineering (IJCSE): Special Issue on Parallel, Distributed and Network-Based Processing (2008). BIB DownloadDetails
• Stiller, Burkhard; Hoßfeld, Tobias: Modeling of P2P-based Video Streaming. In: Joint EC-GIN, EMANICS, and SmoothIT Workshop Economic Traffic Management. Zurich, Switzerland 2008. BIB DownloadDetails
• Gimenez, Juan Pedro Fernandez-Palacios; Rodriguez, Maria Angeles Callejo; Hasan, Hasan; Hoßfeld, Tobias; Staehle, Dirk; Despotovic, Zoran; Kellerer, Wolfgang; Pussep, Konstantin; Papafili, Ionna; Stamoulis, George D.; Stiller, Burkhard: A New Approach for Managing Traffic of Overlay Applications of the SmoothIT Project. In: 2nd International Conference on Autonomous Infrastructure, Management and Security (AIMS 2008). Bremen, Germany 2008. VolltextBIB DownloadDetails
• Hoßfeld, Tobias; Leibnitz, Kenji; Remiche, Marie-Ange: Exact Sojourn Time Distribution in an Online IPTV Recording Service. In: 15th International Conference on Analytical and Stochastic Modelling Techniques and Applications (ASMTA 2008). Nicosia, Cyprus 2008. VolltextBIB DownloadDetails
• Hoßfeld, Tobias; Leibnitz, Kenji: Performance Modeling of Data Aggregation in Wireless Sensor Networks. In: Invited Paper at the Jointly-organized Symposium of the Institute of Intelligent Information and Communications Technology (IICT) at Konan University and the ORSJ (Operations Research Society of Japan). Kobe, Japan 2008. VolltextBIB DownloadDetails
• Hoßfeld, Tobias; Leibnitz, Kenji: A Qualitative Measurement Survey of Popular Internet-based IPTV Systems. In: Second International Conference on Communications and Electronics (HUT-ICCE 2008). Hoi An, Vietnam 2008. VolltextBIB DownloadDetails
• Hoßfeld, Tobias; Hock, David; Tran-Gia, Phuoc; Tutschku, Kurt; Fiedler, Markus: Testing the IQX Hypothesis for Exponential Interdependency between QoS and QoE of Voice Codecs iLBC and G.711. In: 18th ITC Specialist Seminar on Quality of Experience. Karlskrona, Sweden 2008. VolltextBIB DownloadDetails
• Hoßfeld, Tobias; Binzenhöfer, Andreas: Analysis of Skype VoIP Traffic in UMTS: End-to-End QoS and QoE Measurements. In: Computer Networks: The International Journal of Computer and Telecommunications Networking, Jg. 52 (2008) Nr. 3. VolltextBIB DownloadDetails
• Oechsner, Simon; Soursos, Sergios; Papafili, Ioanna; Hoßfeld, Tobias; Stamoulis, George D.; Stiller, Burkhard; Callejo, Maria Angeles; Staehle, Dirk: A framework of economic traffic management employing self-organization overlay mechanisms. In: IWSOS’08. Vienna, Austria 2008. VolltextBIB DownloadDetails
• Zinner, Thomas; Hoßfeld, Tobias; Oechsner, Simon; Tran-Gia, Phuoc: On the Trade-off between Efficiency and Congestion in Location-aware Overlay Networks - Example of a Vertical Handover Support System. In: Eighth International Conference on Peer-to-Peer Computing (P2P 2008). Aachen, Germany 2008. VolltextBIB DownloadDetails
• Staehle, Barbara; Hoßfeld, Tobias; Vicari, Norbert; Kuhnert, Matthias: A Cross-Layer Approach for Enabling Low Duty Cycled ZigBee Mesh Sensor Networks. In: International Symposium on Wireless Pervasive Computing 2008. Santorini, Greece 2008. VolltextBIB DownloadDetails
• Hoßfeld, Tobias; Leibnitz, Kenji; Remiche, Marie-Ange: Modeling of an Online TV Recording System. In: ACM SIGMETRICS Performance Evaluation Review, Jg. 35 (2007) Nr. 2. VolltextBIB DownloadDetails
• Binzenhöfer, Andreas; Hoßfeld, Tobias; Kunzmann, Gerald; Eger, Kolja: Efficient Simulation of Large-Scale P2P Networks: Compact Data Structures. In: Workshop on Modeling, Simulation and Optimization of Peer-to-peer environments (MSOP2P) in conjunction with Euromicro (PDP 2007). Naples, Italy 2007. VolltextBIB DownloadDetails
• Hoßfeld, Tobias; Leibnitz, Kenji: Modeling and Evaluation of an Online TV Recording Service. In: Ninth annual workshop on mathematical performance modeling and analysis MAMA2007, in conjunction with ACM SIGMETRICS ’07 and FCRC ’07. San Diego, CA, USA 2007. VolltextBIB DownloadDetails
• Eger, Kolja; Hoßfeld, Tobias; Binzenhöfer, Andreas; Kunzmann, Gerald: Efficient Simulation of Large-Scale P2P Networks: Packet-level vs. Flow-level Simulations. In: 2nd Workshop on the Use of P2P, GRID and Agents for the Development of Content Networks (UPGRADE-CN’07) in conjunction with the 16th IEEE HPDC. Monterey Bay, California, USA 2007. VolltextBIB DownloadDetails
• Duelli, Michael; Hoßfeld, Tobias; Staehle, Dirk: Impact of Vertical Handovers on Cooperative Content Distribution Systems. In: Seventh IEEE International Conference on Peer-to-Peer Computing (P2P2007). Best Student Paper, Galway, Ireland 2007, S. 177-177. VolltextBIB DownloadDetails
• Hoßfeld, Tobias; Leibnitz, Kenji: Performance Evaluation of an IPTV Recording Service. In: Invited Paper at the Jointly-organized Symposium of the Institute of Intelligent Information and Communications Technology (IICT) at Konan University and the ORSJ (Operations Research Society of Japan). Kobe, Japan 2007. VolltextBIB DownloadDetails
• Hoßfeld, Tobias; Tran-Gia, Phuoc; Fiedler, Markus: Quantification of Quality of Experience for Edge-Based Applications. In: 20th International Teletraffic Congress (ITC20). Ottawa, Canada 2007. VolltextBIB DownloadDetails
• Staehle, Barbara; Hoßfeld, Tobias; Kuhnert, Matthias; Vicari, Norbert: Enabling the Sleep Mode in Non-beaconed 802.15.4 Multihop Networks - A Simulative Investigation. In: 6. GI/ITG KuVS Fachgespräch Drahtlose Sensornetze. Aachen, Germany 2007. VolltextBIB DownloadDetails
• Leibnitz, Kenji; Hoßfeld, Tobias; Wakamiya, Naoki; Murata, Masayuki: Peer-to-Peer vs. Client/Server: Reliability and Efficiency of a Content Distribution Service. In: 20th International Teletraffic Congress (ITC20). Ottawa, Canada 2007. VolltextBIB DownloadDetails
• Kunzmann, Gerald; Nagel, Robert; Hoßfeld, Tobias; Binzenhöfer, Andreas; Eger, Kolja: Efficient Simulation of Large-Scale P2P Networks: Modeling Network Transmission Times. In: Workshop on Modeling, Simulation and Optimization of Peer-to-peer environments (MSOP2P) in conjunction with Euromicro (PDP 2007). Naples, Italy 2007. VolltextBIB DownloadDetails
• Hoßfeld, Tobias; Binzenhöfer, Andreas; Fiedler, Markus; Tutschku, Kurt: Measurement and Analysis of Skype VoIP Traffic in 3G UMTS Systems. In: 4th International Workshop on Internet Performance, Simulation, Monitoring and Measurement (IPS-MoMe 2006). Salzburg, Austria 2006. VolltextBIB DownloadDetails
• Binzenhöfer, Andreas; Hoßfeld, Tobias: Warum Panini Fußballalben auch Informatikern Spaß machen. In: Weigand, Hans-Georg (Hrsg) (Hrsg.): Fußball eine Wissenschaft für sich. Verlag Königshausen & Neumann, 2006, S. 10-10. VolltextBIB DownloadDetails
• Andersen, Frank-Uwe; Tutschku, Kurt; Hoßfeld, Tobias; Oechsner, Simon: Verlässliche Peer-to-Peer Technologie als Steuerungsverfahren für zukünftige mobile Zugangsnetze. In: 11. ITG-Mobilfunktagung, Technologien und Anwendungen, ISBN 3-8007-2942-3. Osnabrück, Germany 2006. BIB DownloadDetails
• Leibnitz, Kenji; Hoßfeld, Tobias; Wakamiya, Naoki; Murata, Masayuki: Modeling of Epidemic Diffusion in Peer-to-Peer File-Sharing Networks. In: The Second International Workshop on Biologically Inspired Approaches to Advanced Information Technology, Bio-ADIT 2006, LNCS 3853. Senri Life Science Center, Osaka, Japan 2006. VolltextBIB DownloadDetails
• Hoßfeld, Tobias; Oechsner, Simon; Tutschku, Kurt; Andersen, Frank-Uwe; Caviglione, Luca: Supporting Vertical Handover by Using a Pastry Peer-to-Peer Overlay Network. In: Mobile Peer-to-Peer Computing MP2P’06, in conjunction with the 4th IEEE International Conference on Pervasive Computing and Communications (PerCom’06). Pisa, Italy 2006. VolltextBIB DownloadDetails
• Hoßfeld, Tobias; Oechsner, Simon; Tutschku, Kurt; Andersen, Frank-Uwe: Evaluation of a Pastry-based P2P Overlay for Supporting Vertical Handover. In: IEEE Wireless Communications and Networking Conference. Las Vegas, NV, USA 2006, S. 6-6. VolltextBIB DownloadDetails
• Hoßfeld, Tobias; Mäder, Andreas; Tutschku, Kurt; Andersen, Frank-Uwe: Time-Discrete Analysis of the Crawling Strategy in an Optimized Mobile P2P Architecture. In: EuroNGI Workshop on. Loveno di Menaggio, Como, Italy 2006. VolltextBIB DownloadDetails
• Hoßfeld, Tobias; Mäder, Andreas; Staehle, Dirk: When Do We Need Rate Control for Dedicated Channels in UMTS?. In: 2006 IEEE 63rd Vehicular Technology Conference. Melbourne, Australia 2006. VolltextBIB DownloadDetails
• Leibnitz, Kenji; Hoßfeld, Tobias; Wakamiya, Naoki; Murata, Masayuki: On Pollution in eDonkey-like Peer-to-Peer File-Sharing Networks. In: 13th GI/ITG Conference on Measurement, Modeling, and Evaluation of Computer and Communication Systems, MMB2006. Nürnberg, Germany 2006. VolltextBIB DownloadDetails
• Mäder, Andreas; Wagner, Bartosz; Hoßfeld, Tobias; Staehle, Dirk; Barth, Hans: Measurements in a Laboratory UMTS Network with time-varying Loads and different Admission Control Strategies. In: 4th International Workshop on Internet Performance, Simulation, Monitoring and Measurement. Salzburg, Austria 2006. VolltextBIB DownloadDetails
• Oechsner, Simon; Hoßfeld, Tobias; Tutschku, Kurt; Andersen, Frank-Uwe: Supporting Vertical Handover by a Self-Organizing Multi-Dimensional P2P Overlay. In: 2006 IEEE 63rd Vehicular Technology Conference. Melbourne, Australia 2006. VolltextBIB DownloadDetails
• Oechsner, Simon; Hoßfeld, Tobias; Tutschku, Kurt; Andersen, Frank-Uwe; Caviglione, Luca: Using Kademlia for the Configuration of B3G Radio Access Nodes. In: Mobile Peer-to-Peer Computing MP2P’06, in conjunction with the 4th IEEE International Conference on Pervasive Computing and Communications (PerCom’06). Pisa, Italy 2006. VolltextBIB DownloadDetails
• Pries, Rastin; Hoßfeld, Tobias; Tran-Gia, Phuoc: On the Suitability of the Short Message Service for Emergency Warning Systems. In: 2006 IEEE 63rd Vehicular Technology Conference. Melbourne, Australia 2006. VolltextBIB DownloadDetails
• Schlosser, Daniel; Hoßfeld, Tobias; Tutschku, Kurt: Comparison of Robust Cooperation Strategies for P2P Content Distribution Networks with Multiple Source Download. In: Sixth IEEE International Conference on Peer-to-Peer Computing (P2P2006). Cambridge, UK 2006. VolltextBIB DownloadDetails
• Hoßfeld, Tobias; Mäder, Andreas; Tutschku, Kurt; Tran-Gia, Phuoc; Andersen, Frank-Uwe; Meer, Hermann de; Dedinski, Ivan: Comparison of Crawling Strategies for an Optimized Mobile P2P Architecture. In: 19th International Teletraffic Congress (ITC19). Beijing, China 2005. VolltextBIB DownloadDetails
• Hoßfeld, Tobias; Staehle, Dirk: A Hybrid Model of the UMTS Downlink Capacity with WWW Traffic on Dedicated Channels. In: Mobile and Wireless Systems, LNCS 3427. Dagstuhl, Germany 2005, S. 20-20. VolltextBIB DownloadDetails
• Hoßfeld, Tobias; Tutschku, Kurt; Andersen, Frank-Uwe: Mapping of File-Sharing onto Mobile Environments: Enhancement by UMTS. In: Mobile Peer-to-Peer Computing MP2P, in conjunction with the 3rd IEEE International Conference on Pervasive Computing and Communications (PerCom’05). Kauai Island, Hawaii 2005. VolltextBIB DownloadDetails
• Hoßfeld, Tobias; Tutschku, Kurt; Andersen, Frank-Uwe: Mapping of File-Sharing onto Mobile Environments: Feasibility and Performance of eDonkey with GPRS. In: WCNC 2005. New Orleans, LA USA 2005. VolltextBIB DownloadDetails
• Oberender, Jens; Andersen, Frank-Uwe; Meer, Hermann de; Dedinski, Ivan; Hoßfeld, Tobias; Kappler, Cornelia; Mäder, Andreas; Tutschku, Kurt: Enabling Mobile Peer-to-Peer Networking. In: Mobile and Wireless Systems, LNCS 3427. Dagstuhl, Germany 2005. VolltextBIB DownloadDetails
• Hoßfeld, Tobias; Tutschku, Kurt; Schlosser, Daniel: Influence of the Size of Swapping Entities in Mobile P2P File-Sharing Networks. In: Peer-to-Peer-Systeme und -Anwendungen. GI/ITG-Workshop in Kooperation mit KiVS 2005, Kaiserslautern 2005. VolltextBIB DownloadDetails
• Hoßfeld, Tobias; Tutschku, Kurt; Andersen, Frank-Uwe; Meer, Hermann de; Oberender, Jens: Simulative Performance Evaluation of a Mobile Peer-to-Peer File-Sharing System. In: Next Generation Internet Networks NGI2005. Rome, Italy 2005. VolltextBIB DownloadDetails
• Hoßfeld, Tobias; Leibnitz, Kenji; Pries, Rastin; Tutschku, Kurt; Tran-Gia, Phuoc; Pawlikowski, Krzysztof: Information Diffusion in eDonkey Filesharing Networks. In: ATNAC 2004. Sydney, Australia 2004, S. 8-8. VolltextBIB DownloadDetails
• Metzger, Florian; Hoßfeld, Tobias; Steindl, Christoph: A Simulation Framework for Evaluating the QoS and QoE of TCP-based Streaming in an LTE Network. In: Proceedings of the 27th International Teletraffic Congress (ITC 27). Ghent, Belgium . VolltextBIB DownloadDetails

Begleitete Abschlussarbeiten:

• Statistische Charakterisierung der Einflussfaktoren auf die Nutzerbindung von Computerspielen (Bachelorarbeit 0, 2017) KurzfassungDetails

  Die Computer- und Videospiel-Industrie wächst stetig weiter und erfreut sich immer größerer Beliebtheit. Insbesondere das Spielerverhalten und die Bindung der Spieler an ein Produkt ist für diese Industrie besonders interessant. Diese Arbeit befasst sich daher besonders mit dem Nutzerverhalten der Videospiel-Plattformen Steam und Twitch.tv. Es wird eine empirische Untersuchung der Spieler- und Zuschauerzahlen durchgeführt und unterschiedlichste Effekte auf die Spielerzahlen dieser Spiele analysiert. Im Zuge dieser Analyse wurden viele Faktoren gefunden, die eine eindeutige Auswirkung auf die Spielerzahlen der gemessenen Computerspiele haben. Allerdings konnten auch einige vermutete Effekte in dieser Messung nicht bestätigt werden.

• Analyse von Bandbreitenmessmethoden in Mobilen Netzen (Masterarbeit Informatik, 2016)
• Alternative call metrics and their performance with support vector classifiers in SPIT detection (Bachelorarbeit Informatik, 2016) KurzfassungDetails
  Mit zunehmener Kostensenkung von Telekommunikationsdiensten und dem zunehmend einfacheren Zugang zu selbigen werden auch Spamanrufe, die in Form und Umfang mehr mit der Spammail als mit der Werbung lokaler Dienstleister gemein haben, wirtschaftlich tragfähig und stellen somit eine Ergänzung im Arsenal der Spammer dar. Um dem entgegenzuwirken wurden für den Geschäftsbereich bereits Methoden entwickelt, die die Anrufdauer und die Vernetzung zwischen Kommunikationspartnern verwenden, um Spamanrufe zu erkennen und den Angerufenen vor dem Anrufer warnen. Whoscall ist ein Dienst, der über eine Smartphoneapp

  Informationen über Anrufe und Anrufer sammelt und dem Nutzer die Möglichkeit gibt, den Anrufer als Spammer zu melden. Die gesammelten Informationen werden den Nutzern dann bei weiteren Anrufen angezeigt, um den Nutzer bei der Entscheidung über Annahme oder Ablehnung des Anrufs zu unterstützen. Basierend auf einem anonymisierten Auszug des Datensatzes von Whoscall evaluieren wir die Leistung sowohl von bereits etablierten Metriken wie der durchschnittlichen Anrufdauer und der normalisierten Anrufsfrequenz als auch Alternativmetriken wie dem Median der Anrufdauer, anrufdauerbasierte Metriken basierend auf dem

  Anrufsverhalten des Benutzers und Metriken basierend auf der Approximation der Verortung des Anrufers relativ zur Verortung des Benutzers oder dessen sozialen Netzwerkes. Wir testen diese Metriken mit dem Support Vector Machine Klassizierungsalgorithmus in der Erkennung von Interaktionen mit Spammern. Dabei wollen wir herausfinden, ob die Klassifizierungsleistung vergleichbar ist mit den aktuellen graph-basierten Methoden, die von FrauDetector verwendet wurden. Unsere Ergebnisse zeigen, dass einige alternative Metriken basierend auf der Nähe des Anrufers zum Benutzer oder der relative Median der Anrufsdauer brauchbare

  Indikatoren zur Verwendung mit graph-basierten Ansätzen sein könnten, diese aber keine bessere Leistung als die normalisierten Anrufsfrequenz versprechen. Weiter stellen wir fest, dass die Klassifizierungsleistung der Support Vector Machine auf dem Niveau von FrauDetector liegt, sich beide Ansätze aber in der Art des verursachten Klassifizierungsfehlers unterscheiden.
• Benutzerorientierte Leistungsbewertung von virtuellen Arbeitsplatzumgebungen mittels Slow-Motion Benchmarking (Masterarbeit Informatik, 2015) KurzfassungDetails
  Im Rahmen dieser Master-Thesis wurde die vMon-Methode entwickelt. Diese stellt ein Werkzeug zur Verfügung, mit dessen Hilfe die Benutzbarkeit und Qualität einer VDIUmgebung zu beurteilen. Diese Beurteilung erfolgt dabei aus der Perspektive der Benutzer. Es wurde eine Referenzimplemetierung der vMon-Methode programmiert und in einer Evaluationsumgebung auf den Prüfstand gestellt. Dabei wurde gezeigt, dass verschiedene Parameter Einfluss auf das Ergebnis der vMon-Methode haben. Neben der richtigen Beurteilung des Ergebnisses sind zudem weitere Experimente in einer VDI-Umgebung mit mehreren VDI-Hosts notwendig. Wenn diese Studien positive Ergebnisse liefern, ist ein Einsatz im Produktivbetrieb sinnvoll. Zwar ist die vMon-Methode, aufgrund ihrer Laufzeit, nicht für die Überwachung einer VDI-Umgebung in Echtzeit geeignet, kann aber in Kombination mit klassischen Überwachungsverfahren (wie zum Beispiel der Überwachung der Systemlast der einzelnen VDI-Hosts) eine gute Ergänzung darstellen. So können Auswirkungen (Impact) und Dringlichkeit (Urgency) eines Ereignisses auf die Benutzer einer VDI-Umgebung bewertet werden. Als Beispiel sei hier der Ausfall eines VDI-Hosts genannt. Durch die vMon-Methode kann nun konkret ermittelt werden, welche Einbußen durch dieses Ereignis in Kauf genommen werden müssen. Dies erleichtert zudem eine bedarfsgerechte Planung der eventuell nötigen Maßnahmen.