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  • 1.
    Ammar, Doreid
    et al.
    Norwegian Univ Sci & Technol, NOR.
    De Moor, Katrien
    Norwegian Univ Sci & Technol, NOR.
    Xie, Min
    Next Generat Serv, Telenor Res, NOR.
    Fiedler, Markus
    Blekinge Institute of Technology, Faculty of Computing, Department of Communication Systems.
    Heegaard, Poul
    Norwegian Univ Sci & Technol, NOR.
    Video QoE Killer and Performance Statistics in WebRTC-based Video Communication2016Conference paper (Refereed)
    Abstract [en]

    In this paper, we investigate session-related performance statistics of a Web-based Real-Time Communication (WebRTC) application called appear. in. We explore the characteristics of these statistics and explore how they may relate to users' Quality of Experience (QoE). More concretely, we have run a series of tests involving two parties and according to different test scenarios, and collected real-time session statistics by means of Google Chrome's WebRTC-internals tool. Despite the fact that the Chrome statistics have a number of limitations, our observations indicate that they are useful for QoE research when these limitations are known and carefully handled when performing post-processing analysis. The results from our initial tests show that a combination of performance indicators measured at the sender's and receiver's end may help to identify severe video freezes (being an important QoE killer) in the context of WebRTC-based video communication. In this paper the performance indicators used are significant drops in data rate, non-zero packet loss ratios, non-zero PLI values, and non-zero bucket delay.

  • 2. Arkoulis, Stamatios
    et al.
    Marias, Giannis
    Frangoudis, Pantelis
    Oberender, Jens
    Popescu, Alexandru
    Fiedler, Markus
    Meer, Hermann de
    Polyzos, George
    Misbehaviour Scenarios in Cognitive Radio Networks2010In: Future Internet, ISSN 1999-5903, E-ISSN 1999-5903, Vol. 2, no 3-4, p. 212-237Article, review/survey (Refereed)
    Abstract [en]

    Recent advances in the fields of Cognitive Radio and the proliferation of open spectrum access promise that spectrum-agile wireless communication will be widespread in the near future, and will bring significant flexibility and potential utility improvements for end users. With spectrum efficiency being a key objective, most relevant research focuses on smart coexistence mechanisms. However, wireless nodes may behave selfishly and should be considered as rational autonomous entities. Selfishness, pure malice or even faulty equipment can lead to behavior that does not conform to sharing protocols and etiquette. Thus, there is a need to secure spectrum sharing mechanisms against attacks in the various phases of the sharing process. Identifying these attacks and possible countermeasures is the focus of this work.

  • 3.
    Arlos, Patrik
    et al.
    Blekinge Institute of Technology, School of Engineering, Department of Telecommunication Systems.
    Fiedler, Markus
    Blekinge Institute of Technology, School of Engineering, Department of Telecommunication Systems.
    A Method to Estimate the Timestamp Accuracy of Measurement Hardware and Software Tools2007Conference paper (Refereed)
    Abstract [en]

    Due to the complex diversity of contemporary Internet applications, computer network measurements have gained considerable interest during the recent years. Since they supply network research, development and operations with data important for network traffic modelling, performance and trend analysis etc., the quality of these measurements affect the results of these activities and thus the perception of the network and its services. One major source of error is the timestamp accuracy obtained from measurement hardware and software. On this background, we present a method that can estimate the timestamp accuracy obtained from measurement hardware and software. The method is used to evaluate the timestamp accuracy of some commonly used measurement hardware and software. Results are presented for the Agilent J6800/J6830A measurement system, the Endace DAG 3.5E card, the Packet Capture Library (PCAP) either with PF_RING or Memory Mapping, and a RAW socket using either the kernel PDU timestamp (ioctl) or the CPU counter (TSC) to obtain timestamps.

  • 4. Arlos, Patrik
    et al.
    Fiedler, Markus
    Influence of the Packet Size on the One-Way Delay in 3G Networks2010Conference paper (Refereed)
    Abstract [en]

    We currently observe a rising interest in mobile broadband, which users expect to perform in a similar way as its fixed counterpart. On the other hand, the capacity allocation process on mobile access links is far less transparent to the user; still, its properties need to be known in order to minimize the impact of the network on application performance. This paper investigates the impact of the packet size on the minimal one-way delay for the uplink in third-generation mobile networks. For interactive and real-time applications such as VoIP, one-way delays are of major importance for user perception; however, they are challenging to measure due to their sensitivity to clock synchronization. Therefore, the paper applies a robust and innovative method to assure the quality of these measurements. Results from measurements from several Swedish mobile operators show that applications can gain significantly in terms of one-way delay from choosing optimal packet sizes. We show that, in certain cases, an increased packet size can improve the one-way delay performance at best by several hundred milliseconds.

  • 5. Arlos, Patrik
    et al.
    Fiedler, Markus
    Influence of the Packet Size on the One-Way Delay on the Down-link in 3G Networks2010Conference paper (Refereed)
    Abstract [en]

    The number of mobile broadband users is increasing. Furthermore, these users have high expectations into the capabilities of mobile broadband, comparable to those in fixed networks. On the other hand, the capacity assignment process on mobile access links is far from transparent to the user, and its properties need to be known in order to minimize the impact of the network on application performance. This paper investigates the impact of the packet size on the characteristics of the one-way delay for the down-link in third-generation mobile networks. For interactive and real-time applications such as VoIP, one-way delays are of major importance for user perception; however, they are challenging to measure due to their sensitivity to clock synchronization. Therefore, the paper applies a robust and innovative method to assure the quality of these measurements. We focus on the down-link as this is still the link that carries the most traffic to the user, and the quality of it will have a significant impact on all IP-based services. Results from measurements from several Swedish mobile operators reveal the possibility to partly control one-way delay and its variability by choosing appropriate packet sizes. In particular, packet sizes leading to the use of WCDMA entail significant but hardly varying one-way delays. On the other hand, we also show that HDSPA networks can deliver large amounts of data at rather high speed, but the cost is a huge variability in the one-way delay.

  • 6. Arlos, Patrik
    et al.
    Fiedler, Markus
    Nilsson, Arne A.
    A Distributed Passive Measurement Infrastructure2005Conference paper (Refereed)
    Abstract [en]

    In this paper we describe a distributed passive measurement infrastructure. Its goals are to reduce the cost and configuration effort per measurement. The infrastructure is scalable with regards to link speeds and measurement locations. A prototype is currently deployed at our university and a demo is online at http://inga.its.bth.se/projects/dpmi. The infrastructure differentiates between measurements and the analysis of measurements, this way the actual measurement equipment can focus on the practical issues of packet measurements. By using a modular approach the infrastructure can handle many different capturing devices. The infrastructure can also deal with the security and privacy aspects that might arise during measurements.

  • 7. Arlos, Patrik
    et al.
    Kommalapati, Ravichandra
    Fiedler, Markus
    Evaluation of Protocol Treatment in 3G Networks2011Conference paper (Refereed)
    Abstract [en]

    In this work, we present a systematic study of how the traffic of different transport protocols (UDP, TCP and ICMP) is treated, in three operational Swedish 3G networks. This is done by studying the impact that protocol and packet size have on the one-way-delay (OWD) across the networks. We do this using a special method that allows us to calculate the exact OWD, without having to face the usual clock synchronization problems that are normally associated with OWD calculations. From our results we see that all three protocols are treated similarly by all three operators, when we consider packet sizes that are smaller than 250~bytes and larger than 1100~bytes. We also show that larger packet sizes are given preferential treatment, with both smaller median OWD as well as a smaller standard deviation. It is also clear that, ICMP is given a better performance compared to TCP and UDP.

  • 8.
    Aziz, Hussein Muzahim
    et al.
    Blekinge Institute of Technology, School of Computing.
    Fiedler, Markus
    Blekinge Institute of Technology, School of Computing.
    Grahn, Håkan
    Blekinge Institute of Technology, School of Computing.
    Lundberg, Lars
    Blekinge Institute of Technology, School of Computing.
    Compressing Video Based on Region of Interest2013Conference paper (Refereed)
    Abstract [en]

    Real-time video streaming suffer from bandwidth limitation that are unable to handle the high amount of video data. To reduce the amount of data to be streamed, we propose an adaptive technique to crop the important part of the video frames, and drop the part that are outside the important part; this part is called the Region of Interest (ROI). The Sum of Absolute Differences (SAD) is computed to the consecutive video frames on the server side to identify and extract the ROI. The ROI are extracted from the frames that are between reference frames based on three scenarios. The scenarios been designed to position the reference frames in the video frames sequence. Linear interpolation is performed from the reference frames to reconstruct the part that are outside the ROI on the mobile side. We evaluate the proposed approach for the three scenarios by looking at the size of the compressed videos and measure the quality of the videos by using the Mean Opinion Score (MOS). The results show that our technique significantly reduces the amount of data to be streamed over wireless networks with acceptable video quality are provided to the mobile viewers.

  • 9. Aziz, Hussein Muzahim
    et al.
    Fiedler, Markus
    Blekinge Institute of Technology, School of Computing.
    Grahn, Håkan
    Blekinge Institute of Technology, School of Computing.
    Lundberg, Lars
    Blekinge Institute of Technology, School of Computing.
    Eliminating the Effects of Freezing Frames on User Perceptive by Using a Time Interleaving Technique2012In: Multimedia Systems, ISSN 0942-4962, E-ISSN 1432-1882, Vol. 18, no 3, p. 251-262Article in journal (Refereed)
    Abstract [en]

    Streaming video over a wireless network faces several challenges such as high packet error rates, bandwidth variations, and delays, which could have negative effects on the video streaming and the viewer will perceive a frozen picture for certain durations due to loss of frames. In this study, we propose a Time Interleaving Robust Streaming (TIRS) technique to significantly reduce the frozen video problem and provide a satisfactory quality for the mobile viewer. This is done by reordering the streaming video frames as groups of even and odd frames. The objective of streaming the video in this way is to avoid the losses of a sequence of neighbouring frames in case of a long sequence interruption. We evaluate our approach by using a user panel and mean opinion score (MOS) measurements; where the users observe three levels of frame losses. The results show that our technique significantly improves the smoothness of the video on the mobile device in the presence of frame losses, while the transmitted data are only increased by almost 9% (due to reduced time locality).

  • 10. Aziz, Hussein Muzahim
    et al.
    Fiedler, Markus
    Grahn, Håkan
    Lundberg, Lars
    Streaming Video as Space – Divided Sub-Frames over Wireless Networks2010Conference paper (Refereed)
    Abstract [en]

    Real time video streaming suffers from lost, delayed, and corrupted frames due to the transmission over error prone channels. As an effect of that, the user may notice a frozen picture in their screen. In this work, we propose a technique to eliminate the frozen video and provide a satisfactory quality to the mobile viewer by splitting the video frames into sub- frames. The multiple descriptions coding (MDC) is used to generate multiple bitstreams based on frame splitting and transmitted over multichannels. We evaluate our approach by using mean opinion score (MOS) measurements. MOS is used to evaluate our scenarios where the users observe three levels of frame losses for real time video streaming. The results show that our technique significantly improves the video smoothness on the mobile device in the presence of frame losses during the transmission.

  • 11.
    Ballesteros, Luis Guillermo Martinez
    et al.
    KTH Royal Inst Technol, Radio Syst Lab RSLab, Stockholm, Sweden..
    Ickin, Selim
    Ericsson Res, Stockholm, Sweden..
    Fiedler, Markus
    Blekinge Institute of Technology, Faculty of Computing, Department of Communication Systems.
    Markendahl, Jan
    KTH Royal Inst Technol, Radio Syst Lab RSLab, Stockholm, Sweden..
    Tollmar, Konrad
    KTH Royal Inst Technol, Radio Syst Lab RSLab, Stockholm, Sweden..
    Wac, Katarzyna
    Univ Copenhagen, DK-1168 Copenhagen, Denmark..
    Energy Saving Approaches for Video Streaming on Smartphone based on QoE Modeling2016In: 2016 13TH IEEE ANNUAL CONSUMER COMMUNICATIONS & NETWORKING CONFERENCE (CCNC), IEEE Communications Society, 2016Conference paper (Refereed)
    Abstract [en]

    In this paper, we study the influence of video stalling on QoE. We provide QoE models that are obtained in realistic scenarios on the smartphone, and provide energy-saving approaches for smartphone by leveraging the proposed QoE models in relation to energy. Results show that approximately 5J is saved in a 3 minutes video clip with an acceptable Mean Opinion Score (MOS) level when the video frames are skipped. If the video frames are not skipped, then it is suggested to avoid freezes during a video stream as the freezes highly increase the energy waste on the smartphones.

  • 12. Binzenhöfer, Andreas
    et al.
    Tutschku, Kurt
    Graben, Björn auf dem
    Fiedler, Markus
    Arlos, Patrik
    A P2P-based framework for distributed network management2006Conference paper (Refereed)
    Abstract [en]

    In this paper we present a novel framework supporting distributed network management using a self-organizing peer-to-peer overlay network. The overlay consists of several Distributed Network Agents which can perform distributed tests and distributed monitoring for fault and performance management. In that way, the concept is able to overcome disadvantages that come along with a central management unit, like lack of scalability and reliability. So far, little attention has been payed to the quality of service experienced by the end user. Our self-organizing management overlay provides a reliable and scalable basis for distributed tests that incorporate the end user. The use of a distributed, self-organizing software will also reduce capital and operational expenditures of the operator since fewer entities have to be installed and operated.

  • 13. Binzenhöfer, Andreas
    et al.
    Tutschku, Kurt
    Graben, Björn auf dem
    Fiedler, Markus
    Arlos, Patrik
    DNA, a P2P-based framework for distributed network management2005Conference paper (Refereed)
    Abstract [en]

    N/A

  • 14. Burakowski, Wojciech
    et al.
    Krieger, Udo R.
    Leibnitz, Kenji
    Beben, Andrzej
    Meo, Michela
    Ors, Tolga
    Garcia-Vidal, Jorge
    Fiedler, Markus
    An overview on activities on wireless networks on the European project COST 2572000Conference paper (Refereed)
    Abstract [en]

    The paper summarises the work on wireless networks inside the COST 257 project, entitled “Impact of new services on the architecture and performance of broadband networks” and chaired by Prof. Tran-Gia of the Technical University of Wurzburg (Germany). This project was established for 4 years (1996-2000) and collected the researchers from 16 European countries represented by 32 organisations. Its topics are modelling, performance, network planning and the analysis of present and future wireless systems.

  • 15. Carlsson, Patrik
    et al.
    Constantinescu, Doru
    Popescu, Adrian
    Fiedler, Markus
    Nilsson, Arne A.
    Delay Performance in IP Routers2004Conference paper (Refereed)
    Abstract [en]

    The main goals of the paper are towards an understanding of the delay process in best-effort Internet for both non-congested and congested networks. A dedicated measurement system is re-ported for delay measurements in IP routers, which follows specifications of the IETF RFC 2679. The system is using both passive measurements and active probing. Dedicated application-layer software is used to generate UDP traffic with TCP-like characteristics. Pareto traffic models are used to generate self-similar traffic in the link. The reported results are in the form of several impor-tant statistics regarding processing delay of a router, router delay for a single data flow, router delay for more data flows as well as end-to-end delay for a chain of routers. We confirm results reported earlier about the fact that the delay in IP routers is generally influenced by traffic characteristics, link conditions and, at some extent, details in hardware implementation and different IOS releases. The delay in IP routers usually shows heavy-tailed characteristics. It may also occasionally show extreme values, which are due to improper functioning of the routers.

  • 16. Carlsson, Patrik
    et al.
    Ekberg, Anders
    Fiedler, Markus
    On an Implementation of a Distributed Passive Measurement Infrastructure2003Other (Other academic)
    Abstract [en]

    Having access to relevant, up-to-date measurement data is a key issue for network analysis in order to allow for efficient Internet performance monitoring and management. New applications keep appearing; user and protocol behavior keep evolving; traffic mixes and characteristics are continuously changing, which implies that some year old traffic traces may not reflect reality any more. In order to give a holistic view of what is going on in the network, passive measurements have to be carried out at different places simultaneously. Other challenges relate to the simultaneous use of one specific measurement point at a certain location for different measurement processes, and to continuously ongoing measurements needed for capturing long-term traffic behaviors. On this background, this paper proposes a passive measurement infrastructure for a campus backbone, consisting of distributed coordinated measurement points, collected in measurement areas, measurement administration and data management. … The framework is generic with regards to the capturing equipment, ranging from simple PCAP based devices to high-end DAG cards, and dedicated ASICs, in order to promote a large deployment of measurement points. This structure allows for an efficient use of passive monitoring equipment in order to supply researchers and network managers with up-to-date and relevant data.

  • 17. Carlsson, Patrik
    et al.
    Fiedler, Markus
    Multifractal Products of Stochastic Processes: Fluid Flow Analysis2000Conference paper (Refereed)
    Abstract [en]

    The consideration of multifractal properties in network traffic has become a well-known issue in network performance evaluation. We analyze the performance of a fluid flow buffer fed by multifractal traffic described by Norros, Mannersalo and Riedi [1]. We describe specific steps in fluid flow analysis, both for finite and infnite buffer sizes, and point out how toovercome numerical problems. We discuss performance results in form of waiting time quantiles and loss probabilities, which help to estimate whether a trffic concentrator constitutes a bottleneck or not.

  • 18. Carlsson, Patrik
    et al.
    Fiedler, Markus
    Nilsson, Arne A.
    Matching Multi-Fractal Process Parameters Against Real Data Traffic2002Conference paper (Refereed)
    Abstract [en]

    Recent analyses of real data/internet traffic indicate that data traffic exhibits long-range dependence as well as self-similar or multi-fractal properties. By using mathematical models of Internet traffic that share these properties we can perform analytical studies of network traffic. This gives us an opportunity to analyse potential bottlenecks and estimate delays in the networks. Processes with multi-fractal properties can be modeled by multiplying the output of Markov Modulated Rate Processes (MMRP) [1] each defined by four parameters. The MMRP are easily used in stochastic fluid flow modeling. This model is also suited for analysis of other traffic types e.g. VoIP and thus, it allows for integration of different traffic types, i.e. time-sensitive voice traffic with best-effort data traffic. Using this model we can calculate performance parameters for each individual stream that enters the system/model. In this paper we show how to construct a multi-fractal process that is matched to measured data from MMRP sub processes.

  • 19. Carlsson, Patrik
    et al.
    Fiedler, Markus
    Nilsson, Arne A.
    Modelling of Ethernet Traffic on Multiple Timescales2004Conference paper (Refereed)
    Abstract [en]

    Ethernet is one of the most common link layer technologies, used in local area networks, wireless networks and wide area networks. There is however a lack of traffic models for Ethernet that is usable in performance analysis. In this paper we use such a model. The model operates on matching multiple moments of the bit rate at several timescales. In order to match the model parameters to measured traffic, five methods have been developed. We use this to model three different links; the BCpOct89 Bellcore trace, an Internet access link and an ADSL link. Our results show that, as the number of sources present on an Ethernet link grows, the model becomes better and less complex.

  • 20. Carlsson, Patrik
    et al.
    Fiedler, Markus
    Tutschku, Kurt
    Chevul, Stefan
    Nilsson, Arne A.
    Obtaining Reliable Bit Rate Measurements in SNMP-Managed Networks2002Conference paper (Refereed)
    Abstract [en]

    The Simple Network Management Protocol, SNMP, is the most widespread standard for Internet management. As SNMP stacks are available on most equipment, this protocol has to be considered when it comes to performance management, traffic engineering and network control. However, especially when using the predominant version 1, SNMPv1, special care has to be taken to avoid erroneous results when calculating bit rates. In this work, we evalute six off-the-shelf network components. We demonstrate that bit rate measurements can be completely misleading if the sample intervals that are used are either too large or too small. We present solutions and work-arounds for these problems. The devices are evaluated with regards to their updating and response behavior.

  • 21. Chevul, Stefan
    et al.
    Isaksson, Lennart
    Fiedler, Markus
    Karlsson, Johan
    Lindberg, Peter
    Measurement of application-perceived throughput of an E2E VPN connection using a GPRS network2005Conference paper (Refereed)
    Abstract [en]

    N/A

  • 22. Chevul, Stefan
    et al.
    Karlsson, Johan
    Isaksson, Lennart
    Fiedler, Markus
    Lindberg, Peter
    Strandén, Lars
    Measurements of Application-Perceived Throughput in DAB, GPRS, UMTS and WLAN Environments2005Conference paper (Refereed)
    Abstract [en]

    Communication services are expected to deliver the desired information in a timely manner without challenging the user’s patience. The corresponding offers by networks are reflected in user- or applications-perceived throughput, which is measured end-to-end for different mobile and wireless networks, namely Digital Audio Broadcast (DAB), General Packet Radio Service (GPRS), Universal Mobile Telecommunication Systems (UMTS), and Wireless Local Area Networks (WLAN). The measurements are based on passive monitoring of throughput statistics for active test traffic and reveal amongst others different kinds of changes of traffic burstiness induced by mobile up- and downlinks and by buffering, respectively. The results will be used for seamless communication, i.e. automatic network selection within the project PIITSA (Personal Information for Intelligent Transport Systems through Seamless communications and Autonomous decisions) aiming at maintaining user-perceived performance and security at the desired levels while keeping communication cost as small as possible.

  • 23. Ciszkowski, Tomasz
    et al.
    Eliasson, Charlott
    Fiedler, Markus
    Kotulski, Zbigniew
    Lupu, Radu
    Mazurczyk, Wojciech
    SecMon: end-to-end quality and security monitoring system2008In: Annales UMCS Informatica, ISSN 1732-1360, Vol. AI 8, no 1, p. 185-201Article in journal (Refereed)
    Abstract [en]

    The Voice over Internet Protocol (VoIP) is becoming a more available and popular way of communication for the Internet users. This also applies to the Peer-to-Peer (P2P) systems and merging these two have already proven to be successful (e.g. Skype). Even the existing standards of VoIP provide an assurance of security and Quality of Service (QoS), however, these features are usually optional and supported by a limited number of implementations. As a result, the lack of mandatory and widely applicable QoS and security guaranties makes the contemporary VoIP (P2P VoIP systems even more so than client-server ones) systems vulnerable to attacks and network disturbances. In this paper we are facing these issues and propose the SecMon system, which simultaneously provides a lightweight security mechanism and improves quality parameters of the call. SecMon is intended specially for VoIP service over P2P networks and its main advantage is that it provides authentication, data integrity services, adaptive QoS and (D)DoS attacks detection. Moreover, the SecMon approach represents a low-bandwidth consumption solution that is transparent to the users and possesses a self-organizing capability. The above- mentioned features are accomplished mainly by utilizing two information hiding techniques: digital audio watermarking and network steganography. These techniques are used to create covert channels that serve as transport channels for lightweight QoS measurement’s results. Furthermore, these metrics are aggregated in a reputation system that is used for the best route path selection in the P2P network. The reputation system also helps to mitigate (D)DoS attacks, maximize performance and increase transmission efficiency in the network.

  • 24. Ciszkowski, Tomasz
    et al.
    Mazurczyk, Wojciech
    Kotulski, Zbigniew
    Hossfeld, Tobias
    Fiedler, Markus
    Collange, Denis
    Towards Quality of Experience-based Reputation Models for Future Web Service Provisioning2009Conference paper (Refereed)
    Abstract [en]

    This paper concerns the applicability of reputations systems for assessing Quality of Experience (QoE) for web services in Future Internet. Reputation systems provide mechanisms to manage subjective opinions in societies and yield general scoring of a particular behavior. Thus, they are likely to become an important ingredient of Future Internet. Parameters being under evaluation by reputation system may vary greatly and, particularly, may be chosen to assess the users’ satisfaction with (composite) web services. Currently, this satisfaction is usually expressed with QoE, which represents subjective users’ opinions. The goal is to predict users’ satisfaction based on reputation values. This may be beneficial for service providers in terms of checking the fulfillment of SLAs, for retaining QoE on the satisfaction level for other users sharing the same network or service resources, and for providing the users with indications which resource to choose in order to maximize its experience.

  • 25. Ciszkowski, Tomasz
    et al.
    Mazurczyk, Wojciech
    Kotulski, Zbigniew
    Hossfeld, Tobias
    Fiedler, Markus
    Blekinge Institute of Technology, School of Computing.
    Collange, Denis
    Towards Quality of Experience-based reputation models for future web service provisioning2012In: Telecommunications Systems, ISSN 1018-4864, E-ISSN 1572-9451, Vol. 51, no 4, p. 283-295Article in journal (Refereed)
    Abstract [en]

    This paper concerns the applicability of reputations systems for assessing Quality of Experience (QoE) for web services in Future Internet. Reputation systems provide mechanisms to manage subjective opinions in societies and yield a general scoring of a particular behavior. Thus, they are likely to become an important ingredient of Future Internet. Parameters being under evaluation by a reputation system may vary greatly and, particularly, may be chosen to assess the users’ satisfaction with (composite) web services. Currently, this satisfaction is usually expressed by QoE, which represents subjective users’ opinions. The goal of this paper it to present a novel framework of web services where a reputation system is incorporated for users satisfaction tracking and prediction. This approach is a beneficial tool, which enables providers to facilitate service adaptation according to users’ expectations and maintain QoE on a satisfying level. Presented reputation system operates in an environment of composite services running on a client and server side. It makes this approach highly suitable for effective QoE differentiating and maximizing user experience for specific customer profiles even the service and network resources are shared.

  • 26. Collange, Denis
    et al.
    Mahdi, Hajji
    Shaikh, Junaid
    Blekinge Institute of Technology, School of Computing.
    Fiedler, Markus
    Blekinge Institute of Technology, School of Computing.
    Arlos, Patrik
    Blekinge Institute of Technology, School of Computing.
    User Impatience and Network Performance2012Conference paper (Refereed)
    Abstract [en]

    In this work, we analyze from passive measurements the correlations between the user-induced interruptions of TCP connections and different end-to-end performance metrics. The aim of this study is to assess the possibility for a network operator to take into account the customers' experience for network monitoring. We first observe that the usual connection-level performance metrics of the interrupted connections are not very different, and sometimes better than those of normal connections. However, the request-level performance metrics show stronger correlations between the interruption rates and the network quality-of-service. Furthermore, we show that the user impatience could also be used to characterize the relative sensitivity of data applications to various network performance metrics.

  • 27. Cousin, Philippe
    et al.
    Fricker, Samuel
    Blekinge Institute of Technology, Faculty of Computing, Department of Software Engineering.
    Felmy, Dean
    Le Gall, Franck
    Fiedler, Markus
    Blekinge Institute of Technology, Faculty of Computing, Department of Communication Systems.
    Validation and Quality in FI-PPP e-Health Use Case, FI-STAR Project2014Conference paper (Refereed)
  • 28. Dahlberg, Anders
    et al.
    Zepernick, Hans-Jürgen
    Mercankosk, Guven
    Fiedler, Markus
    Multi AP concepts for SCO traffic in a Bluetooth based Radio Infrastructure Network2002Conference paper (Refereed)
    Abstract [en]

    In this paper, we consider a radio infrastructure network (RIN), which consists of Bluetooth Access Points (APs) to provide services to ad hoc users. The RIN inherently supports both voice and data connectivity. Since Bluetooth offers the establishment of Synchronous Circuit-Oriented (SCO) traffic, the concept under study features a low-cost alternative to indoor cellular base stations. However, a single AP can serve a maximum of only three SCO channels and may not be capable of satisfying the voice traffic demands in hot spots. In order to offer more bandwidth in a location with high voice traffic, two or more APs may be placed in the same coverage area. Respective AP clusters will be denoted as Multi APs. Three Multi AP concepts for doing the SCO allocation are presented and discussed. Our findings show that employing Multi APs significantly reduces the blocking probability.

  • 29. Dahlberg, Anders
    et al.
    Zepernick, Hans-Jürgen
    Mercankosk, Guven
    Fiedler, Markus
    Multi AP Strategies for SCO Traffic in a Bluetooth based Wireless LAN2003Conference paper (Refereed)
    Abstract [en]

    We consider a Wireless Local Area Network (WLAN) consisting of Bluetooth Access Points (APs). Thus, it inherently offers both ad-hoc voice and data connectivity. As Bluetooth supports Synchronous Circuit-Oriented (SCO) traffic, the concept under study features a low-cost alternative to indoor cellular base stations. Due to the limitation of only three available SCO channels per AP, several APs can be placed in the same coverage area to satisfy voice traffic demands in hot spots. Such AP clusters will be denoted as Multi AP. Three Multi AP strategies for handling the SCO allocation are presented and discussed in terms of signaling and mean time to connect. Our findings show that employing Multi APs significantly reduces the blocking probability. A simple dimensioning rule for the number of APs is given.

  • 30. Duong, Quang Trung
    et al.
    Zepernick, Hans-Jürgen
    Fiedler, Markus
    Cross-Layer Design for Integrated Mobile Multimedia Network with Strict Priority Traffic2010Conference paper (Refereed)
    Abstract [en]

    In mobile multimedia networks, different traffic classes require various levels of quality of service (QoS). In this paper, we propose a cross-layer design to provide diverse QoS provisions for integrated realtime/non-realtime traffic by jointly taking into account the physical layer, data link layer, and application layer. Specifically, at the physical layer, adaptive modulation and coding (AMC) is employed to cope with the time-varying nature of fading channels whereas impairments due to queuing effects are considered at the data link layer. At the application layer, realtime and non-realtime traffic are classified into high and low priority classes, respectively, with strict priority levels. The cross-layer scheme is characterized as a discrete Markov modulated Poisson process. Solving the steady state probability of this Markov model readily enables us to investigate several important performance metrics such as packet drop rate due to buffer overflow and packet error rate due to transmission errors and network impairments. Our proposed cross-layer design is verified by comparing the analytical results with Monte-Carlo simulations. Furthermore, it has been shown that the proposed cross-layer design can flexibly guarantee QoS requirements for each traffic class.

  • 31. Duursma, Rick
    et al.
    Fiedler, Markus
    Iterative computations of bit rate summary statistics at inlet and outlet of a discrete time fluid queue2006Conference paper (Refereed)
    Abstract [en]

    Network performance management is facing the challenge of provisioning advanced services with stringent delay and throughput requirements. For this reason, shortage of network capacity implying delay or loss, so-called bottlenecks, have to be identified and to be classified. The latter tasks imply the need for tractable analytical performance models. As we are particularly interested in the traffic flow properties, we focus on a discrete-time fluid flow traffic model. The fluid model considers averages of bit rates on small time scales. These averages can easily be measured, and thus, bit rate statistics for data streams entering and leaving a bottleneck can be obtained. The fluid flow model helps us to obtain analytical estimates on the impact of network entities on data streams and their statistics, i.e., efficiently predict the effects of bottlenecks on data streams. In this work we derive formulae for an iterative calculation of summary statistics such as the bit rate distribution and autocorrelation function. In addition, a corresponding simulation has been implemented, and the simulation results agree closely with the exact solutions. With the aid of the derived formulae we are able to match the model to observations.

  • 32. Egger, Sebastian
    et al.
    Hossfeld, Tobias
    Schatz, Raimund
    Fiedler, Markus
    Blekinge Institute of Technology, School of Computing.
    Waiting times in quality of experience for web based services2012Conference paper (Refereed)
    Abstract [en]

    A considerable share of applications such as web or e-mail browsing, online picture viewing and file downloads imply waiting times for their users, which is due to the turn-taking of information requests by the user and correspoding response times until each request is fulfilled. Thus, end-user quality perception in the context of interactive data services is dominated by waiting times; the longer the latter, the less satisfied the user becomes. As opposed to heavily researched multimedia experience, perception of waiting times is still not strongly explored in the context of Quality of Experience (QoE). This tutorial will contribute to closing this gap. In its first part, it addresses perception principles and discusses their applicability towards fundamental relationships between waiting times and resulting QoE. It then investigates to which extent the same relationships can also be used to describe QoE for more complex services such as web browsing. Finally, it discusses applications where waiting times determine QoE, amongst other factors. For example, the past shift from UDP media streaming to TCP media streaming (e.g. youtube.com) has extended the relevance of waiting times also to the domain of online video services. In particular, user-perceived quality suffers from initial delays when applications are launched, as well as from freezes during the delivery of the stream. These aspects, which have to be traded against each other to some extent, will be discussed mainly for HTTP video streaming in the last part of this tutorial.

  • 33.
    Eivazzadeh, Shahryar
    et al.
    Blekinge Institute of Technology, Faculty of Engineering, Department of Health.
    Sanmartin Berglund, Johan
    Blekinge Institute of Technology, Faculty of Engineering, Department of Health.
    Larsson, Tobias
    Blekinge Institute of Technology, Faculty of Engineering, Department of Mechanical Engineering.
    Fiedler, Markus
    Blekinge Institute of Technology, Faculty of Computing, Department of Technology and Aesthetics.
    Anderberg, Peter
    Blekinge Institute of Technology, Faculty of Engineering, Department of Health.
    Most Influential Qualities in Creating Satisfaction Among the Users of Health Information Systems: A Study in Seven EU Countries2018In: JMIR Medical InformaticsArticle in journal (Refereed)
    Abstract [en]

    Background:

    Several models suggest how the qualities of a product or service influence user satisfaction. Models, such as the Customer Satisfaction Index (CSI), Technology Acceptance Model (TAM), and Delone and McLean Information Systems Success (D&M IS), demonstrate those relations and have been used in the context of health information systems.

    Objective:

    We want to investigate which qualities foster greater satisfaction among patient and professional users. In addition, we are interested in knowing to what extent improvement in those qualities can explain user satisfaction and if this makes user satisfaction a proxy indicator of those qualities.

    Methods:

    The Unified eValuation using ONtology (UVON) method was utilised to construct an ontology of the required qualities for seven e-health applications being developed in the FI-STAR project, a European Union (EU) project in e-health. The e-health applications were deployed across seven EU countries. The ontology included and unified the required qualities of those systems together with the aspects suggested by the Model for ASsessment of Telemedicine applications (MAST) evaluation framework. Two similar questionnaires, for 87 patient users and 31 health professional users, were elicited from the ontology. In the questionnaires, user was asked if the system has improved the specified qualities and if the user was satisfied with the system. The results were analysed using Kendall correlation coefficients matrices, incorporating the quality and satisfaction aspects. For the next step, two Partial Least Squares Structural Equation Modelling (PLS-SEM) path models were developed using the quality and satisfaction measure variables and the latent construct variables that were suggested by the UVON method.

    Results:

    Most of the quality aspects grouped by the UVON method are highly correlated. Strong correlations in each group suggest that the grouped qualities can be measures which reflect a latent quality construct. The PLS-SEM path analysis for the patients reveals that the effectiveness, safety, and efficiency of treatment provided by the system are the most influential qualities in achieving and predicting user satisfaction. For the professional users, effectiveness and affordability are the most influential. The parameters of the PLS-SEM that are calculated allow for the measurement of a user satisfaction index similar to CSI for similar health information systems.

    Conclusions:

    For both patients and professionals, the effectiveness of systems highly contributes to their satisfaction. Patients care about improvements in safety and efficiency, while professionals care about improvements in the affordability of treatments with health information systems. User satisfaction is reflected more in the users' evaluation of system output and fulfilment of expectations, but slightly less in how far the system is from ideal. Investigating satisfaction scores can be a simple, fast way to infer if the system has improved the abovementioned qualities in treatment and care.

  • 34. Eliasson, Charlott
    et al.
    Fiedler, Markus
    Dimensioning study for road user charging2008Conference paper (Refereed)
    Abstract [en]

    Road User Charging (RUC) solutions based on the concept of thin clients rely upon timely delivery of Heavy Goods Vehicles (HGV) positions towards a RUC provider, which then performs the map matching and the calculation of the road user charges. In order to avoid data loss and late delivery, a proper dimensioning of the system is required. For the Swedish case, we investigate the feasibility of legacy mobile and wireless systems (in particular GPRS, UMTS and WLAN) for both streaming and bulk transfer of positioning data, and we determine sensible combinations of sampling and reporting intervals in terms of efficient and economic reporting. We also highlight a couple of traps regarding the dimensioning, in particular of sending patterns that might cause overload at the server side of the system. It becomes obvious that mobile networks can well cope with the extra load caused by reporting HGVs, while bulk transfer in wireless hot-spots can be used as a complementary solution.

  • 35. Eliasson, Charlott
    et al.
    Fiedler, Markus
    Jørstad, Ivar
    A criteria-based evaluation framework for authentication schemes in IMS2009Conference paper (Refereed)
    Abstract [en]

    The IP Multimedia Subsystem (IMS) is regarded as one of the most prominent enablers for successful service provisioning across different access network technologies and devices. While new paradigms, e.g. seamless communication, enter the IMS, existing solutions, e.g. for authentication, need to be redefined, which is one of the major activities within the EUREKA!-funded Mobicome project, involving operators, manufacturers and academia. As there exist several candidate solutions for providing seamless authentication, there is a need for a set of criteria that helps to select the candidate that fulfils those criteria in a bestpossible way. Given this background, this position paper proposes a framework of criteria for the evaluation of authentication schemes in IMS. The primary criteria are security, user-friendliness and simplicity. Inbetween these criteria, the secondary criteria can be found. These are awareness, usability and algorithms. Each criterion, both primary and secondary, is then also divided into one or several substantiating sub-criteria. The discussion of the criteria is followed by a description of the evaluation methodology, which comprises both qualitative and quantitative evaluations such as SWOT analysis, use of NIST and ISO guidelines, user rankings, and measurements of authentication times. The paper is concluded with an outlook on future work, including studies and experiments.

  • 36. Eliasson, Charlott
    et al.
    Fiedler, Markus
    Jørstad, Ivar
    Evaluation of Authentication Schemes Based on Security, User-Friendliness and Complexity2008Conference paper (Other academic)
    Abstract [en]

    In this work we are going to study and evaluate several SIMbased and non SIM-based authentication schemes for use in an IMS platform. The work will be done as part of the EUREKA!-funded Mobicome project. In this project eleven partners are participating in order to get a working prototype of the new generation network IMS to run. The major idea of the extended IMS functionality is seamlessness, both regarding network and device switching. Seamlessly working security solutions are a self-evident must in this context. In order to satisfy the customer while meeting technical boundary conditions, solutions must work in a satisfactory manner in many respects. On this background, this paper is a position paper, stating started and planned work on the evaluation of candidate security solutions for seamless IMS-based communications. First, the primary criteria of evaluation, namely security, user-friendliness and simplicity, are discussed. Then, the secondary criteria, which include awareness, usability and algorithms, are described. Along with the criteria, both sub-criteria and corresponding parameters are outlined. After this, the methodology for the evaluation is described. Finally, an outlook is presented at the end of the chapter.

  • 37. Eriksén, Sara
    et al.
    Dittrich, Yvonne
    Fiedler, Markus
    Aurell, Marie
    It Takes More Than Two... Developing a TANGO-Arena for Regional Cooperation around E-government2003Conference paper (Refereed)
    Abstract [en]

    The TANGO e-government arena is an on-going project in Southern Sweden, funded by the Innovative Actions of the European Regional Development Fund. The aim of the project is to establish cooperation between the public sector, private enterprise and university-based research in designing public e-services. Our starting point is e-government understood as co-construction of technology, society and citizenship in everyday life. This approach is based on the Scandinavian Tradition of Participatory Design, but also motivated by on-going technological development. In cooperating around development of new, integrated services, catering to various categories of users as well as to a growing diversity of mobile technologies, we are aiming to establish feedback channels between practice and theory, between use and design, and between different academic disciplines where we see a need to synchronize the models and methods we work with. Our current research questions focus on exploring and managing multi-perspectivity as a resource for design.

  • 38.
    Eriksén, Sara
    et al.
    Blekinge Institute of Technology, School of Engineering, Department of Interaction and System Design.
    Eliasson, Charlott
    Fiedler, Markus
    Blekinge Institute of Technology, School of Engineering, Department of Telecommunication Systems.
    Chevul, Stefan
    Blekinge Institute of Technology, School of Computing.
    Ekelin, Annelie
    Blekinge Institute of Technology, School of Engineering, Department of Interaction and System Design.
    Mapping service quality: measuring and comparing quality of experience and quality of service for Internet-based map services2007Conference paper (Refereed)
    Abstract [en]

    In this paper, we present an on-going research project in which we are focusing on examining how users of map-based services on-line experience the quality of these services when the traffic load is high, and how the users' experiences of acceptable or not acceptable quality can be related to measurable parameters which can be used to manage network traffic and improve technical solutions. The project is a multi- and interdisciplinary project in cooperation between researchers within human work science and informatics, and researchers within telecommunication systems. Additionally, there are two external partners in the project: a provider of Internet-based map services, and a municipality which uses this provider's map services regularly. One of the main methodological issues addressed in the project is how laboratory based, quantitative research methods from research on Quality of Service in the telecommunication systems area can be related to qualitative research methods focusing on workplace- or other live-world based use situations and Quality of Expereince as defined by users of the services. How can experiments and studies be designed, and results shared, such that both network traffic measuring and evaluation of user experiences retain their own paradigmatic validity and relevance, while fruitfully informing service design?

  • 39. Erman, David
    et al.
    Fiedler, Markus
    Collaborative Video Streaming in Future Networks: Extended Abstract2009Conference paper (Refereed)
    Abstract [en]

    Video streaming and mesh-based peer-to-peer file sharing are two of the most bandwidth-demanding applications in the current Internet. In particular non-popular video streaming is on the increase, and future networks are likely to be even more involved in this type of application. Another expected ma jor defining trait of future network is heterogeneity, not only with respect to access technologies, but also several other factors, such as user mobility and terminal capability. This extended abstract delineates some of the most pressing challenges to be faced by mesh-based collaborative video streaming systems, with particular focus on maintaining adequate Quality of Experience (QoE).

  • 40. Fiedler, Markus
    Direct Evaluation of Required Capacity for ATM Multiplex1998Other (Other academic)
    Abstract [en]

    Required capacity may be used in Connection Admission Control, Network Resource Management or for purposes of planning and dimensioning. From the well-known loss probability formula for the bufferless fluid ow model, an implicit formula for the required capacity for a given QoS per connection may be derived which turns into a closed formula when it is evaluated in a special way. This formula, whose complexity is comparable to that of the original loss probability formula, allows for a quick and exact evaluation of required capacity. Differences to other possibilities of required capacity evaluation are shown, and potential problems affecting the use of the formula are discussed. Finally, the suitability of the equivalent bandwidth in COST-242 for required capacity evaluations is demonstrated.

  • 41. Fiedler, Markus
    Euro-NGI D.JRA.6.1.1: State-of-the-art with regards to user-perceived Quality of Service and quality feedback2004Other (Other academic)
    Abstract [en]

    This deliverable D.JRA.6.1.1 presents a review of the state-of-the-art with regards to Quality of Service from the user's perspective and quality feedback, which is the topic of the corresponding work package WP.JRA.6.1 as part of the Joint Research Activity "Socio-Economic Aspects of Next Generation Internet" of the Network of Excellence "Euro-NGI". The document contains a survey of Quality of Service-related standards and discusses the current status regarding Quality of Servce in the Internet. The central role of the user is highlighted, and methods how to relate user perception to technical parameters on application and network level are discussed. Furthermore, currently existing quality feedback and management facilities in Internet are reviewed. Complementary work of the involved partners within these fields is presented, showing the broad range of compentence of the partners within the scope of JRA.6.1. Finally, relevant research issues are identified, providing a promising basis for future joint research.

  • 42. Fiedler, Markus
    Formula for the required capacity of an ATM multiplexer1998Conference paper (Refereed)
    Abstract [en]

    This contribution deals with a formula for the capacity an ATM multiplexer must at least have to accomodate the loss probability demands of all connections. So it can be used for connection admission control as well as for network resource management purposes. The formula is based on the bufferless fluid flow multiplexer model. It allows for a more exact capacity evaluation than if equivalent bandwidths are used on a per-connection basis. On the other hand, it merely requires a computational effort which is comparable to evaluating the mean of a given distribution. Indeed, the bottleneck is the convolution of probability ensity functions, on which the formula operates. Two steps to reduce the computational effort are proposed: a framework for convolution operations, consisting of pre-computed probability density functions, and a suitable truncation of the state space.

  • 43. Fiedler, Markus
    Generic Network Service Components for Networks of the Future2009Conference paper (Other academic)
    Abstract [en]

    The ability to dynamically compose services is growing in importance. Appreciable network connectivity has become a mandatory part of successful service provisioning. From the end user point-of-view, good experience of networked services is an obligation no matter which network is used. There is an ongoing discussion on Networks of the Future including Future Internet, facing the fact that current Internet and its key protocol IP – located at the waist of the well-known hourglass model – are facing difficulties to cope with (a) the ever-increasing multitude and demands of applications from the top, and (b) the diversity of network access technologies at the bottom. The basic data transport and in particular the implicit control feedback facilities provided by a standard socket interface are by far insufficient for many services. As an example, seamless communication – facing the need to hand over applications and their data traffic between devices and networks without breaks – needs to work around these limitations. During the recent years, Service Oriented Architectures (SOA) arose to facilitate the composition of business processes. In their context, network connectivity may be seen as a service itself, provided by a Network Service Component (NSC) that implements a communication function with an Application Programming Interface (API). In order to make service supply chains work as expected such a network service component has to offer well-defined network transport facilities according to agreed-upon Service Level Agreements (SLA). So far, the notion NSC typically appeared in product specifications and patent applications. In literature, Service Components (SC) are typically discussed in the context of (web) service composition, with network connectivity taken for granted. This paper proposes a generic structure of a network service component. It enumerates some early approaches to NSC from the area of seamless communications. The use case of a NSC-based seamless video service is discussed.

  • 44. Fiedler, Markus
    Internet performance issues for safety-critical applications2004Conference paper (Refereed)
    Abstract [en]

    Networked safety-critical applications have to rely upon a certain Quality of Service (QoS). Internet, however, might not be that reliable in that respect. Thus, quality feedback towards the application is a crucial aspect. This contribution reviews typical origins of QoS problems and discusses possibilities how to monitor them. It also presents a lightweight monitoring solution for bandwidth problems which can be used for quality feedback towards the application.

  • 45. Fiedler, Markus
    Modeling and Analysis of Wireless Network Segments with aid of Teletraffic Fluid Flow Models2000Report (Other academic)
    Abstract [en]

    The fluid flow model is used to model variable server and link rates, as they appear in mobile channels due to fading, bit error recovery and failed channel reservations. Assuming a Gilbert-Elliott model for the channel, the influence of transmission quality on network Quality of Service (QoS) might be studied. Thus, the fluid flow model assumes the role of a model that might be used for dimensioning and performance evaluation both at the edge and inside a network. We present a user-friendly, contemporary, flexible, fast and numerically stabilized computing environment for the fluid flow model with a well-known user interface that is able to handle multiple users and that might be used as well for batch processing. We discuss two case studies that emphasize the crucial impact of the relationship between server and source dynamics on QoS.

  • 46. Fiedler, Markus
    On Resource Sharing and Careful Overbooking for Network Virtualization2009Conference paper (Refereed)
    Abstract [en]

    Network Virtualization implies the need for sharing network resources. However, exclusive resource allocation to users drives blocking probabilities and cost while potentially leaving precious resources under-utilized in constrained environments. Motivated by these observations, this paper analyzes careful overbooking according to Service Level Agreements that specify desired degrees of availability. Besides of full availability of the requested resources, a second level of limited availability, implying a well-defined reduction of the allocated resource, is taken into account. Particular attention is paid to the gain borderline, representing the possibility of accommodating one extra user beyond exclusive allocation without violating the SLAs. Simple but telling formulae provide insights into requirements for careful overbooking, worst-case capacity reduction factors from full to limited availability, and the conditions under which it is sensible to integrate users with different activity levels.

  • 47. Fiedler, Markus
    On resource sharing and careful overbooking for network virtualization2011In: International Journal of Communication Networks and Distributed Systems, ISSN 1754-3916, E-ISSN 1754-3924, Vol. 6, no 3, p. 232-248Article in journal (Refereed)
    Abstract [en]

    Network Virtualization implies the need for sharing network resources. However, exclusive resource allocation to users drives blocking probabilities and cost while potentially leaving precious resources under-utilized in constrained environments. Motivated by these observations, this paper analyzes careful overbooking according to Service Level Agreements that specify desired degrees of availability. Besides of full availability of the requested resources, a second level of limited availability, implying a well-defined reduction of the allocated resource, is taken into account. Particular attention is paid to the gain borderline, representing the possibility of accommodating one extra user beyond exclusive allocation without violating the SLAs. Simple but telling formulae provide insights into requirements for careful overbooking, worst-case capacity reduction factors from full to limited availability, and the conditions under which it is sensible to integrate users with different activity levels. We also link capacity reductions to potential decreases in Quality of Experience.

  • 48.
    Fiedler, Markus
    Blekinge Institute of Technology, Faculty of Computing, Department of Communication Systems.
    On the Limited Potential of Buffers to Improve Quality of Experience2014Conference paper (Refereed)
    Abstract [en]

    This paper investigates the potential of improving the Quality of Experience (QoE) of pervasive video delivery by buffering. It reveals the importance of delivering video without freezes to the end user. It then introduces a fluid flow model that leads to a closed formula for the freeze probability, and matches measured distributions of on- and off-times to this model's exponential distributions in order to underline its feasibility. The closed formula for the freeze probability is then used to investigate the impact of two buffer size adaptation policies, one additive and one multiplicative with regards to the deviation of the average off-time from its nominal value. It is proven that, besides of some specific conditions in the additive case, the freeze probability grows with the disturbance, which means that even an increased buffer size implies worse performance and thus QoE. It also points out a way out of this dilemma, which is to try to reduce off times by reducing the utilization of the mobile link.

  • 49. Fiedler, Markus
    PERIMETER: Privacy-preserving contract-less, user-centric, seamless roaming for Always Best Connected Future Internet2009Conference paper (Refereed)
    Abstract [en]

    PERIMETER is a new EU FP7 project, whose main objective is to establish a new paradigm of user-centricity for advanced networking. In contrast to network-centric approaches, user-centric strategies could achieve true seamless mobility. Putting the user at the centre rather than the operator enables the user to control his or her identity, preferences and credentials, and so seamless mobility is streamlined, enabling mobile users to be “Always Best Connected” in multiple-access multiple-operator networks of the Future Internet. For this purpose, PERIMETER will develop and implement protocols designed to cope with increased scale, complexity, mobility and requirements for privacy, security, resilience and transparency of the Future Internet. These include appropriate mechanisms for network selection based on Quality of Experience; innovative implementation of “Distributed A3M” protocols for Fast Authentication, Authorisation and Accounting based on privacy-preserving digital identity models. All these mechanisms will be designed to be independent from the underlying networking technology and service provider, so that fast, inter-technology handovers will be possible.

  • 50. Fiedler, Markus
    Quality feedback flows in future networks2009In: Elektrotechnik & Informationstechnik, ISSN 0932-383X, Vol. 126, no 7Article in journal (Refereed)
    Abstract [en]

    The current rise in community-based content sharing and growing popularity of personalised multimedia transmission is accompanied by user-side quality demands. Internet, on the other hand, still provides merely best-effort service and thus only implicit feedback on critical network conditions through packet loss and delays. In order to satisfy future quality demands, feedback on quality problems needs to become much more explicit than what is the case today. In order to highlight the potential for improvement, this paper first identifies and analyses today’s feedback flows between users, applications, networks and the corresponding service providers. Based on this inventory, a new kind of feedback system employing self-organising overlay technology is introduced and exemplified. This future-proof system, developed within the European series of Networks of Excellence EuroNGI, EuroFGI and EuroNF, provides added feedback value to the above-mentioned stakeholders and furthermore a smooth transition path from current legacy towards future service management solutions.

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