Endre søk
Begrens søket
1234 151 - 196 of 196
RefereraExporteraLink til resultatlisten
Permanent link
Referera
Referensformat
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Treff pr side
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sortering
  • Standard (Relevans)
  • Forfatter A-Ø
  • Forfatter Ø-A
  • Tittel A-Ø
  • Tittel Ø-A
  • Type publikasjon A-Ø
  • Type publikasjon Ø-A
  • Eldste først
  • Nyeste først
  • Skapad (Eldste først)
  • Skapad (Nyeste først)
  • Senast uppdaterad (Eldste først)
  • Senast uppdaterad (Nyeste først)
  • Disputationsdatum (tidligste først)
  • Disputationsdatum (siste først)
  • Standard (Relevans)
  • Forfatter A-Ø
  • Forfatter Ø-A
  • Tittel A-Ø
  • Tittel Ø-A
  • Type publikasjon A-Ø
  • Type publikasjon Ø-A
  • Eldste først
  • Nyeste først
  • Skapad (Eldste først)
  • Skapad (Nyeste først)
  • Senast uppdaterad (Eldste først)
  • Senast uppdaterad (Nyeste først)
  • Disputationsdatum (tidligste først)
  • Disputationsdatum (siste først)
Merk
Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
  • 151. Persson, Jan A.
    et al.
    Davidsson, Paul
    Boldt, Martin
    Carlsson, Bengt
    Fiedler, Markus
    Evaluation of Road User Charging Systems: The Swedish Case2007Konferansepaper (Fagfellevurdert)
  • 152. Polyzos, George
    et al.
    Giannis, Marias
    Arkoulis, Stamatios
    Frangoudis, Pantelis
    Fiedler, Markus
    Popescu, Adrian
    Meer, Hermann de
    Herkenhöner, Ralph
    Fischer, Andreas
    Oberender, Jens
    ASPECTS: Agile spectrum security2011Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Cognitive Radio (CR) promises to provide better spectrum utilization and increase the availability of (on demand) broadband access to the Network of the Future. CR relies on devices that can sense their (radio) environment, understand it, and model it, so that they can exploit the spectrum through appropriate transmission parameters (in the space, time, and frequency domains) that do not interfere with legacy and/or licensed devices using the same spectrum in the same general area. According to the CR paradigm, the use of the spectrum that is not used by primary (licensed) users is opportunistic. Secondary users sense the spectrum and decide to use it on their own, possibly following additional rules and protocols. Because multiple such CR devices (secondary users) can find themselves in the same area and compete for the same spectrum, the question that arises is whether these devices behave fairly and appropriately. The opportunities are there for competing CR devices to try to grab more resources through the spreading of misinformation and impersonation of licensed devices.

  • 153.
    Popescu, Adrian
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Erman, David
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Ilie, Dragos
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Fiedler, Markus
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Popescu, Alexandru
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Vogeleer, Karel De
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Seamless Roaming: Developments and Challenges2011Inngår i: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, Vol. 5233, s. 795-807Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The chapter reports on recent developments and challenges focused on seamless handover. These are subject for the research projects MOBICOME and PERIMETER, recently granted by the EU EUREKA and EU STREP FP7, respectively. The research projects are considering the recently advanced IP Multimedia Subsystem (IMS), which is a Set of technology standards put forth by the Internet Engineering Task Force (IETF) and two Third Generation Partnership Project groups, namely 3GPP and 3GPP2. The foundation of seamless handover is provided by several components, the most important ones being the handover, mobility management, connectivity management and Internet mobility. The paper provides an intensive analysis of these components.

  • 154. Popescu, Adrian
    et al.
    Erman, David
    Ilie, Dragos
    Popescu, Alexandru
    Fiedler, Markus
    Vogeleer, Karel De
    Seamless Roaming: Developments and Challenges2008Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    The paper reports on recent developments and challenges focused on seamless handover. These are subject for the research projects MOBICOME and PERIMETER, recently granted by the EU EUREKA and EU STREP FP7, respectively. The research projects are considering the recently advanced IP Multimedia Subsystem (IMS), which is a set of technology standards put forth by the Internet Engineering Task Force (IETF) and two Third Generation Partnership Project groups, namely 3GPP and 3GPP2. The foundation of seamless handover is provided by several components, the most important ones being the handover, mobility management, connectivity management and Internet mobility. The paper provides an intensive analysis of these components.

  • 155. Popescu, Adrian
    et al.
    Erman, David
    Vogeleer, Karel De
    Popescu, Alexandru
    Fiedler, Markus
    ROMA: A Middleware Framework for Seamless Handover2009Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The paper reports on a new middleware architecture suggested for seamless handover. The middleware is part of an architectural solution suggested by Blekinge Institute of Technology (BTH) for seamless handover, which is implemented at the application layer. This architecture is sub ject for the PERIMETER STREP and MOBICOME pro jects, granted by the EU FP7 and EUREKA, respectively. Compared to the existent handover solutions, implemented at the link layer and network layer, this solution offers the advantage of less dependence on physical parameters and more flexibility in the design of architectural solutions. Furthermore, it allows for dynamic combinations of services and underlying transport substrates (overlays and networks). The suggested middleware, called ROMA, represents a software system with two sets of APIs, one for application writers and another one for interfacing various overlay and un- derlay systems. ROMA thus provides a transport-agnostic platform for future Internet applications. The paper provides a short description of the ROMA middleware, with par- ticular focus on API design and address translation.

  • 156. Popescu, Adrian
    et al.
    Erman, David
    Vogeleer, Karel De
    Popescu, Alexandru
    Fiedler, Markus
    ROMA: A Middleware Framework for Seamless Handover2011Inngår i: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, Vol. 5233, s. 784-794Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The chapter reports on a new middleware architecture suggested for seamless handover. The middleware is part of an architectural solution suggested by Blekinge Institute of Technology (BTH) for seamless handover, which is implemented at the application layer. This architectures is subject for the PERIMETER STREP and MOBICOME projects, granted by the EU FP7 and EUREKA, respectively. The suggested middleware called ROMA represents a software system with two sets of Application Programmer Interface (API), one for application writers and another one for interfacing various overlay and underlay systems. ROMA thus provides a transport-agnostic platform for future Internet applications. The paper provides a short description of the ROMA middleware, with particular focus on API design and address translation.

  • 157. Popescu, Adrian
    et al.
    Fiedler, Markus
    Kouvatsos, Demetres
    Content Distribution over IP: Developments and Challenges2006Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This is an invited tutorial on "Content Distribution over IP: Developments and Challenges", with special focus on overlay routing

  • 158. Popescu, Adrian
    et al.
    Ilie, Dragos
    Erman, David
    Fiedler, Markus
    Popescu, Alexandru
    Vogeleer, Karel de
    An Application Layer architecture for Seamless Roaming2009Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The paper advances a new architecture for seamless roaming, which is implemented at the application layer. This architecture is subject for the research projects PERIMETER and MOBICOME, recently granted by the EU STREP FP7 and EUREKA, respectively. The research challenges are on mobility management, security, QoE management, overlay routing, node positioning, mobility modeling and prediction, middleware and handover. The foundation of seamless handover is provided by several components, the most important ones being the handover, mobility management, connectivity management and Internet mobility. The paper provides an analysis of these components

  • 159.
    Popescu, Adrian
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för datalogi och datorsystemteknik.
    Yao, Yong
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för datalogi och datorsystemteknik.
    Fiedler, Markus
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för teknik och estetik.
    Ducloux, Xavier
    Harmonic, FRA.
    Video Distribution Networks: Models and Performance2018Inngår i: Greening Video Distribution Networks: Energy-Efficient Internet Video Delivery / [ed] Adrian Popescu, Springer, 2018, s. 227-Kapittel i bok, del av antologi (Fagfellevurdert)
    Abstract [en]

    The creation, distribution and delivery of video content is a sophisticated process with elements like video acquisition, preprocessing and encoding, content production and packaging as well as distribution to customers. IP networks are usually used for the transfer of video signals. The treatment of video content is also very complex, and we have a multidimensional process with elements like content acquisition, content exchange and content distribution. The focus of the chapter is on the presentation of models that can be used to characterize the main elements in a video distribution chain. These models are about video coding and compression, video streaming, video traffic models, energy consumption models, system performance, concepts of performance optimization and QoE- and energy-optimal streaming.

  • 160. Popescu, Alexandru
    et al.
    Erman, David
    Fiedler, Markus
    Kouvatsos, Demetres
    A Multi-Dimensional CAN Approach to CRN Routing2010Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The paper reports on an innovative approach to the management of Cognitive Radio Networks (CRNs). As part of achieving this functionality, a new architecture implemented at the application layer is presented. The research challenges for developing a CRN management solution are on addressing, sensing and prediction, routing, decision making and middleware. Cognitive radio networks are expected to address and to solve several important challenges like, e.g., opportunistic spectrum access, spectrum heterogeneity, network heterogeneity and the provision of diverse Quality of Service (QoS) to different applications. Consequently, a number of management functions are necessary to address the associated challenges with the management of CRNs. The paper provides a brief introduction to these components while focusing on the CR routing, addressing and content representation.

  • 161. Popescu, Alexandru
    et al.
    Erman, David
    Fiedler, Markus
    Kouvatsos, Demetres
    A Multi-Reality Approach to CRN Data Representation2010Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Cognitive Radio Networks (CRNs) are emerging as a viable solution for exploiting the available spectrum and solving overcrowding in the operating bands. Several dimensions in the process of identification, management and routing need to be handled to overcome the challenges associated with the management of CRNs. A very important topic in achieving an effective and flexible management solution is related to the data representation of the different CRN dimensions. Scalability, high tolerance to churn and low latencies in accessing the stored data are fundamental characteristics in order to keep up with the dynamic nature of a mobile environment. Accordingly, to achieve a robust data representation that can handle all these requirements in an efficient way we focus our attention on peer-to-peer (P2P) systems. These systems are well known for providing an efficient platform to develop scalable and robust applications. Hence, in this paper we investigate using geometric multi-dimensional data representation and addressing system based on basic CAN functionality. Results obtained in our experiments are reported, providing useful information to improve the resilience to churn of our system.

  • 162. Popescu, Alexandru
    et al.
    Erman, David
    Fiedler, Markus
    Kouvatsos, Demetres
    Routing in Content Addressable Networks: Algorithms and Performance2009Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Over the last years, virtual networking has evolved towards becoming a dominant platform for the deployment of new services and applications such as large-scale data sharing, multimedia services, application-level multicast communication. A consequence of this evolution is that features like robust routing, efficient search, scalability, decentralization, fault tolerance, trust and authentication have become of paramount importance. Since network virtualization basically represents the process of combining resources of different types, two distinct aspects stand out. The first aspect is virtualization of hardware on network entities, while the second being in essence a virtualized network such as an overlay network. In this context, overlay networks act as enablers by providing the addressing and routing substrates needed to implement a virtualized network structure. In this paper, we focus on the second aspect of network virtualization and consider the specific case of structured overlay networks with a particular focus on Content Addressable Networks (CAN). An investigation of the existing approaches for structured P2P overlay networks is provided, where we point out their advantages and drawbacks. The essentials of CAN architecture are presented and based on that, we report on the implementation of a CAN simulator. Our initial goal is to use the simulator for investigating the performance of the CAN with focus on the routing algorithm. Preliminary results obtained in our experiments are reported as well. The results indicate that greedy routing algorithms perform better than non-greedy algorithms.

  • 163. Popescu, Alexandru
    et al.
    Erman, David
    Fiedler, Markus
    Popescu, Adrian
    Kouvatsos, Demetres
    A Middleware Framework for Communication in Cognitive Radio Networks2010Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Cognitive radio networks are expected to address and resolve important operational challenges such as opportunistic spectrum access, spectrum and network heterogeneities and requests for the provision of diverse Quality-of-Service (QoS) for different applications. Accordingly, a number of network functionalities are required to take into account these challenges towards the efficient management of cognitive radio networks. This paper advances a new architecture for the management of cognitive radio networks. The architecture is designed and developed at the application layer and incorporates sensing and prediction, addressing and routing, middleware and decision making. Accordingly, a number of management functions are required to address the challenges associated with the management of cognitive radio networks. The paper provides an analysis of these components as well.

  • 164.
    Popescu, Alexandru
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Fiedler, Markus
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    On Data Representation in Cognitive Radio Networks2012Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Dynamic Spectrum Access (DSA) and routing in Cognitive Radio Networks (CRNs) present challenging operational and technological problems in beyond 4G networks. Additionally, the provision of Quality of Experience (QoE) for different applications and Cognitive Radio Devices (CRDs) requires new management architectures and knowledge information approaches. The paper advances a new data-representation solution to allow efficient multi-constraint routing and multi dimensional adaptation for multiple cognitive radio (CR) dimensions like space, frequency, power and time. The goal of the paper is to advance a system for CRN data representation, which allows optimized communication according to QoE demands between Secondary Users (SUs).

  • 165.
    Popescu, Alexandru
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Fiedler, Markus
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    On Routing in Cognitive Radio Networks2012Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Abstract—Cognitive Radio Networks (CRNs) are expected toaddress and to resolve important technological and operational challenges of future networks, such as Dynamic Spectrum Access (DSA), routing in heterogeneous networks and provision of Quality of Experience (QoE) for different applications. Accordingly, a number of new terminal and network functionalities are required to solve the technical problems and to provide efficient management of CRNs. The paper advances a new solution for routing in CRNs, providing communication between Secondary Users (SUs) occupying different so-called Spectrum Opportunities (SOPs), i.e., portions of spectrum not occupied by Primary Users (PUs). This entails solving a complex process composed by two fundamental elements. These elements are multi-constraint routing and multi-dimensional adaptation for multiple cognitive radio dimensions like space, frequency, power and time. The goal of the paper is to develop optimization algorithms necessary to provide end-to-end (e2e) routing paths for communication between SUs with associated QoE demands.

  • 166.
    Popescu, Alexandru
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Fiedler, Markus
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    On Routing in Cognitive Radio Networks (extended version)2012Inngår i: MTA Review, ISSN 1843-3391, Vol. XXII, nr 4, s. 197-212Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    Cognitive Radio Networks are expected to resolve important technological and operational challenges of future networks, such as Dynamic Spectrum Access, routing in heterogeneous networks and provisioning of Quality of Experience for different applications. Accordingly, a number of new terminal and network functionalities are required to solve the technical problems and to provide efficient management. The paper advances a new solution for routing in Cognitive Radio Networks, providing communication between Secondary Users occupying different socalled Spectrum Opportunities, i.e., portions of spectrum not occupied by Primary Users. This entails solving a complex process composed by two fundamental elements. These are the multi-constraint routing and the multi-dimensional adaptation for multiple cognitive radio dimensions like space, frequency, power and time. The goal of the paper is to develop optimization algorithms necessary to provide end-to-end routing paths for communication between Secondary Users with associated Quality of Experience demands.

  • 167.
    Popescu, Alexandru
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Yao, Yong
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Fiedler, Markus
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    On Mobility Generated Signaling in Cognitive Radio Network Clusters2013Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The rapid migration towards wireless connectivity means that the radio spectrum must be efficiently utilized to conserve capacity and to avoid overcrowding, particularly in densely populated areas. Towards this goal, cognitive radio technology is a key concept. The basic idea is to allow unlicensed users access to licensed spectrum, under the condition that the interference perceived by the licensed users is minimal. A novel architecture designed and developed at the application layer has been suggested by researchers at Blekinge Institute of Technology for the management of cognitive radio networks. Emphasizing on signaling facilities in this architecture and common control channel dimensioning aspects, the paper reports on simulation results regarding node mobility for a particular network model. To reduce the energy consumption of mobile devices, innovative signaling strategies are a very important topic to consider in novel mobile system architectures.

  • 168.
    Popescu, Alexandru
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Yao, Yong
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Fiedler, Markus
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Popescu, Adrian
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    A Management Architecture for Multimedia Communication in Cognitive Radio Networks2015Inngår i: Multimedia over Cognitive Radio Networks: Algorithms, Protocols, and Experiments / [ed] Hu, F; Kumar, S, CRC Press, 2015, s. 3-31Kapittel i bok, del av antologi (Annet vitenskapelig)
  • 169.
    Popescu, Alexandru
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Yao, Yong
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Fiedler, Markus
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Popescu, Adrian
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Communication Mechanisms for Cognitive Radio Networks2013Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Comprehensive communication in cognitive radio networks is an important research topic within the scope of empowering cognitive radio functionality in beyond-4G mobile networks. Providing communication for secondary users without interference with primary users is an ambitious task, which requires innovative management architecture designs and routing solutions. Operational challenges such as opportunistic spectrum access, solving problems related to spectrum and network heterogeneities and requests for the provisioning of Quality-of-Service to different applications must be resolved. As part of a novel management architecture, the paper advances a new approach to end-to-end communication in cognitive radio networks based on combining ad-hoc algorithms with spectrum mobility algorithms.

  • 170.
    Popescu, Alexandru
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Yao, Yong
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Fiedler, Markus
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Popescu, Adrian
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Network Architecture to Support Multimedia over CRN2014Inngår i: Multimedia over Cognitive Radio Networks: Algorithms, Protocols, and Experiments / [ed] Hu, Fei; Kumar, Sunil, CRC Press , 2014Kapittel i bok, del av antologi (Fagfellevurdert)
  • 171. Schatz, Raimund
    et al.
    Fiedler, Markus
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Skorin-Kapov, Lea
    QoE-Based Network and Application Management2014Inngår i: QUALITY OF EXPERIENCE: ADVANCED CONCEPTS, APPLICATIONS AND METHODS / [ed] Moller, S.; Raake, A., Springer , 2014, s. 411-426Kapittel i bok, del av antologi (Fagfellevurdert)
    Abstract [en]

    This chapter presents an overview of a set of recently proposed QoE-based management approaches that all try so resolve a central dilemma: maximizing user satisfaction while at the same time maximizing resource efficiency and economy. To this end, it first builds bridges between recent approaches towards QoE-based Network Management and standardized Network Management functions. This is contrasted by a discussion of recent approaches towards QoE-based Application Management. Further, it is shown how both Network Management and Application Management can work together in concert. Finally, open issues regarding a better integration of management and QoE are outlined.

  • 172. Schumacher, Jens
    et al.
    Dobler, Martin
    Dillon, Eileen
    Power, Gemma
    Fiedler, Markus
    Erman, David
    Vogeleer, Karel De
    Ramos, Manuel Oritz
    Argente, José Rodríguez
    Providing an User Centric Always Best Connection2010Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Although Quality of Experience (QoE) is perceived as a subjective measure of a user’s experience, it is the only measure that actually counts to a user of a service. It is essential to identify, quantify and ultimately improve the perception of QoE for a user. The PERIMETER project improves the user’s experience by identifying a more user-centric network selection, based on QoE calculations and user preferences. PERIMETER defines a generic QoE model which forms the basis for QoE signalling and QoE based content adaptation support. This paper provides an insight into how user centric seamless mobility is being achieved by PERIMETER, beginning with an explanation of QoE and the need for preferences. Next, more details of the complete system, including QoE management, user feedback and the final delivery, are provided. Finally, an outlook is given on PERIMETER’s future plans and its contributions to research in the Future Internet.

  • 173.
    Shaikh, Junaid
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Fiedler, Markus
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Arlos, Patrik
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Collange, Denis
    Modeling and Analysis of Web Usage and Experience Based on Link-Level Measurements2012Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Internet traffic monitoring and analysis have been playing a crucial role in understanding and characterizing user behavior on the web. In particular, ON-OFF models capture the essential phases of user communication with web servers. The OFF phases reflect both deliberate and accidental gaps in the traffic flow. In this paper, we present a passive monitoring and analysis method devised to assist in the identification of such traffic gaps that may result in the degradation of Quality of Experience (QoE). Our first contribution consists in a revised ON-OFF model to cater for OFF times reflecting accidental gaps which are induced by the network. Second, a wavelet-based criterion is proposed to differentiate between the network-induced traffic gaps and user think times. The proposed method is intended to be implemented in near-real-time as it does not require any deep packet inspection. Both web service providers and network operators may use this method to obtain objective evidence of the appearance of QoE problems from link-level measurements.

  • 174.
    Shaikh, Junaid
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Fiedler, Markus
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Arlos, Patrik
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Collange, Denis
    On the Use of TCP Interruptions to Assess User Experience on Web2010Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The Quality of Experience (QoE) is becoming an increasingly popular research area among the ICT related industry and academia.There is a need of a user-centric approach for the design and monitoring of network applications and services. It stimulates the need for an online passive mechanism to monitor the user activity in real-time. The mechanism may vary with the type of application. In this work, we keep our focus on Web browsing application as it is one of the most popular applications on the Internet. The aim is to let the users browse freely and monitor their activity instead of asking them subjectively about their usage experience. Monitoring of the TCP connection interruptions could be one of the ways to have indications about users’ feelings on the Web. This is based on the idea that, in case of bad performance, users break a Web browsing session by pressing a reset or stop button in the browser hence generating a TCP reset on TCP flow level. In this present work, we carry this analysis further to observe the user interruptions in relation to transfer sizes and durations. We want to see how the users react to bad performance and try to explain why we observe smaller mean transfer sizes. Do the users avoid launching large transfers in the case of bad performance or do they try to get the same files but stop the transfers that are becoming too long?

  • 175.
    Shaikh, Junaid
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Fiedler, Markus
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Arlos, Patrik
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Minhas, Tahir Nawaz
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Collange, Denis
    Classification of TCP Connection Termination Behaviors for Mobile Web2011Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Many emerging smart applications and services employ Web technology, and users nowadays surf the Web from any device via any kind of access network. Typically, high page latencies trigger users to abort ongoing transfers, resulting in the abrupt terminations of the TCP connections. This paper presents a systematic study of the termination process of the TCP connections and identifies the reasons behind the observed sequences of termination flags. Monitoring and classification of the termination behavior of the TCP connections can provide indications about the user-perceived performance of Web transfers. From the results, it is observed that the TCP termination behavior is heavily-dependent on the client-side application. Therefore, a set of criteria is required to identify the abortions made by the user.

  • 176.
    Shaikh, Junaid
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Fiedler, Markus
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Collange, Denis
    Quality of Experience from End-to-End and Network Perspective2008Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Knowing user experience resulting from the performance of network services is an extremely important target for service providers and researchers. Effects of even slight disturbances in network performance were not so damaging for user satisfaction level ever before than they are in today’s changing network conditions in heterogeneous network environment, involving fixed, wireless and mobile networks. Quality of Service (QoS) is the ability of network to provide a service with an assured service level and Quality of Experience (QoE) is how a user perceives the usability of a service when in use. Monitoring the QoS can be an important indicator for the level of user satisfaction if the monitored parameters are strongly correlated to that user satisfaction. This paper presents a comprehensive analysis on the changing user behaviour at different service performance levels through both objective and subjective measurements. At first, it discusses the correlation of subjective grading of the service by users with service performance parameters and observes certain thresholds on the performance parameters where user experience changes. This analysis is based on the results of web surfing experiments on a testbed. Secondly, it discusses the correlation of traffic characteristics of user sessions with session throughputs in order to observe the dependence of these characteristics on network performance metrics. This discussion is based on traffic launched by real users on an ADSL network. Finally, the objectively measured traffic characteristics like user session volumes are compared to subjective responses of the users to see to what extent the session volumes reflect the user satisfaction level.

  • 177.
    Shaikh, Junaid
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Fiedler, Markus
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Collange, Denis
    Quality of experience from user and network perspectives2010Inngår i: Annales des télécommunications, ISSN 0003-4347, E-ISSN 1958-9395, Vol. 65, nr 1-2, s. 47-57Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The impact of network performance on user experience is important to know, as it determines the success or failure of a service. Unfortunately, it is very difficult to assess it in real-time on an operational network. Monitoring of network-level performance criteria is easier and more usual. But the problem is then to correlate these network-level Quality of Service (QoS) to the Quality of Experience (QoE) perceived by the users. Efforts have been done in the previous years to map user behaviour to traffic characteristics on the network to QoS. However, being able to successfully relate these traffic characteristics to user satisfaction is not a simple task and still requires further investigations. In this work, we try to associate on one side the correlations between various traffic characteristics measured on an operational network and on the other side the user experience tested on an experimental platform. Our aim is to observe some pronounced trends regarding relationships between both types of results. More precisely, we want to validate how and to what extent the volumes of user sessions represent the level of user satisfaction. Along this way, we need to revise classical relationships between some of the network performance indicators such as loss, download time and throughput in order to strengthen the understanding of this impact on each other and on user satisfaction. This preliminary study is based on the application web.

  • 178.
    Shaikh, Junaid
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Fiedler, Markus
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Minhas, Tahir Nawaz
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Arlos, Patrik
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Collange, Denis
    Inferring User-perceived Performance of Network by Monitoring TCP Interruptions2012Inngår i: Network Protocols and Algorithms, ISSN 1943-3581, E-ISSN 1943-3581, Vol. 4, nr 2, s. 49-67Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The fluctuating performance of wireless and mobile networks has triggered the need for smart algorithms to assess the user perception, resulting from the quality of network services. While efforts have been done to model the user experience resulting from the network performance, there is still the need for practical methods to assess the user-perceived performance, in the real environment. In this work, we present a set of criteria to observe the user behavior on the Web, passively from the network-level. The criteria are based on the monitoring of TCP control flags and HTTP requests. Thus, information about user actions performed in the web browser can be inferred by monitoring the TCP termination flags and by keeping track of the HTTP requests. Along the way, we also present some anomalies observed in the TCP connection termination process, which may result in performance degradation of Web transfers.

  • 179.
    Shaikh, Junaid
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Fiedler, Markus
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Minhas, Tahir Nawaz
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Arlos, Patrik
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Collange, Denis
    Passive Methods for the Assessment of User-perceived Quality of Delivery2011Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Passive monitoring of user-perceived performance degradation is an important tool for service providers to improve customer loyalty. In this paper, we discuss our on-going work on the development of two network-based methods to objectively assess the user-perceived network performance. One method is based on the observation of TCP connections interrupted by the users. This method allows us to detect user’s interest in the service in relation to the network performance. Another method is simple and based on the identification of traffic gaps in the user transfers that may hurt the user perception. This work, amongst others, provokes a discussion on the impact of the frequency and duration of such gaps.

  • 180.
    Shaikh, Junaid
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Fiedler, Markus
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Paul, Pangkaj
    Egger, Sebastian
    Guyard, Frederic
    Back to Normal? Impact of Temporally Increasing Network Disturbances on QoE2013Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Brief episodes of network faults and performance issues adversely affect the user Quality of Experience (QoE). Besides damaging the current opinions of users, these events may also shape user’s future perception of the service. Therefore, it is important to quantify the impact of such events on QoE over time. In this paper, we present our findings on the temporal aspects of user feedback to disturbances on networks. These findings are based on subjective user tests performed in the context of web browsing on an e-commerce website. The results of this study suggest that the QoE drops significantly every time the page load time grows. The after-effects of network disturbances on user QoE remain visible even when the network problems are over, i.e., users do not immediately return to the same level of opinion scores as compared to the corresponding pre-disturbance phase. They tend to remember their recent experiences. Our results also show that there are four segments of users that exist with regards to their feedback to page load times. Network operators may customize their services according to each segment of users to raise the overall QoE. Finally, we show that the exponential relationship provides best fits of QoE and page load times for all segments of users.

  • 181.
    Shaikh, Junaid
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Minhas, Tahir Nawaz
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Arlos, Patrik
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Fiedler, Markus
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Evaluation of delay performance of traffic shapers2010Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In network emulation, traffic shapers are used to shape the performance of the network. They are provided with certain inputs in a test environment to vary the network performance accordingly in order to investigate the effects of different network conditions on applications in real yet emulated scenarios. However, it is very important for the shapers to work as supposed in order to successfully realize the desired network conditions. They may make the results of network emulations unrealistic and unreliable if their functioning is not according to the desired specification. In this work, we evaluate the delay shaping of three traffic shapers, NIST Net, Netem and KauNet through the results obtained from a number of experiments. A comparison of the output of their delay shaping is presented. This comparison can enable us to select the most suitable shaper based on the required shaping. Effects of hardware platforms on the shaping are also filtered out by performing the experiments with shapers installed on Advance Micro Devices (AMD) and Intel platforms separately. Different Protocol Data Unit (PDU) sizes are used in the experiments to test the influence of packet sizes on the shaping. These delay evaluation results are then complemented by the Coefficient of Throughput Variation (CoTV) results.

  • 182.
    Swartling, Mikael
    et al.
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, Avdelningen för elektroteknik.
    Ström Bartunek, Josef
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, Avdelningen för elektroteknik.
    Nilsson, Kristian
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, Avdelningen för elektroteknik.
    Gustavsson, Ingvar
    Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, Avdelningen för elektroteknik.
    Fiedler, Markus
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Simulations of the VISIR Open Lab Platform2012Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper presents a queue simulation of the VISIR Open Lab Platform. A model of the platform and statistical distributions of how users interact with the system based on real log files are presented. The system is then simulated in order to determine how many concurrent students that can be allowed to use the platform while at the same time keeping a low response time to ensure the quality of the service. The results show, in a worst case setup with approximately 300 ms response time per experiment, that roughly 100 concurrent users is an upper limit to ensure an average response time below 2 s. The results also show that raising the limit of the desired experiment response time does not necessarily increase the number allowed concurrent users significantly once the system is saturated. However, improving the experiment response time can significantly increase the number of users that can simultaneously be connected.

  • 183.
    Tran, Hung
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Zepernick, Hans-Jürgen
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Fiedler, Markus
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Phan, Hoc
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Outage Probability, Average Transmission Time, and Quality of Experience for Cognitive Radio Networks over General Fading Channels2012Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper, we examine the delay performance in cognitive radio networks (CRNs) over general fading channels where secondary users are allowed to simultaneously access the spectrum licensed by primary users. In particular, subject to the peak interference power constraint, we investigate the effect of general fading channels on the delivery delay of data packets and acknowledgements (ACKs). A lower bound of outage probability and an upper bound of average transmission time are derived by utilizing the concept of timeout. Specifically, we apply the above results to investigate the quality of experience (QoE) for various fading channels, such as one-sided Gaussian, Rayleigh, Nakagami-m and Weibull channels. The numerical results indicate that the delay of ACKs under severe fading leads to a degradation of system performance.

  • 184.
    Ullah, Muhammad
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Fiedler, Markus
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Wac, Katarzyna
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    On the ambiguity of Quality of Service and Quality of Experience requirements for eHealth services2012Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The use of end-to-end communication systems as a medium of delivery for electronic healthcare (eHealth) services is considered to be uncertain, with respect to its reliability leading to hesitation in acceptance of such services. There exist different influential dimensions that pose stringent requirements on end-to-end communication systems, influence user perception and might hinder user acceptance. The later is referred to as Qualityof Experience (QoE), which among others depends on the Quality of Service (QoS) of the end-to-end communication system. QoE is considered as a key component determining user acceptance. This paper identifies and analyzes characteristics of a set of eHealth services and the influential dimensions resulting in different QoS requirements and potential impact of QoS on QoE. It highlights the role of QoS and QoE for acceptance of these services. The issue of non-uniform views regarding QoS parameter specifications and related requirements, clinically acceptable thresholds and their qualitative representation in eHealth literature is reviewed and presented.

  • 185. Vo, Nguyen-Son
    et al.
    Duong, Trung Quong
    Zepernick, Hans-Jürgen
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Fiedler, Markus
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    A Cross-Layer Optimized Scheme and Its Application in Mobile Multimedia Networks With QoS Provision2016Inngår i: IEEE Systems Journal, ISSN 1932-8184, E-ISSN 1937-9234, Vol. 10, nr 2, s. 817-830Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    To cope with the rapid growth of multimedia applications that requires dynamic levels of quality of service (QoS), cross-layer (CL) design, where multiple protocol layers are jointly combined, has been considered to provide diverse QoS provisions for mobile multimedia networks. However, there is a lack of a general mathematical framework to model such CL scheme in wireless networks with different types of multimedia classes. In this paper, to overcome this shortcoming, we therefore propose a novel CL design for integrated real-time/non-real-time traffic with strict preemptive priority via a finite-state Markov chain. The main strategy of the CL scheme is to design a Markov model by explicitly including adaptive modulation and coding at the physical layer, queuing at the data link layer, and the bursty nature of multimedia traffic classes at the application layer. Utilizing this Markov model, several important performance metrics in terms of packet loss rate, delay, and throughput are examined. In addition, our proposed framework is exploited in various multimedia applications, for example, the end-to-end real-time video streaming and CL optimization, which require the priority-based QoS adaptation for different applications. More importantly, the CL framework reveals important guidelines as to optimize the network performance.

  • 186. Vogeleer, Karel De
    et al.
    Erman, David
    Fiedler, Markus
    Popescu, Adrian
    A Lightweight Macro-Mobility Framework2010Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper presents the design of a lightweight framework to provide vertical handover for macro-mobility on handheld devices. The framework is designed for mobile-controlled handover and does not require modification of the Internet infrastructure. The framework enables users to control the entire vertical handover process so handover decisions are driven by user preferences rather than ISP considerations. UDP tunneling is used as the basis for seamless roaming. Support nodes participate in mobility management by keeping track of the mobile users. We elaborate on a proof-of-concept implementation targeted to be deployed on the Android platform.

  • 187. Vogeleer, Karel De
    et al.
    Ickin, Selim
    Erman, David
    Fiedler, Markus
    PERIMETER: A User-Centric Mobility Framework2010Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This demo shows a prototype of a user-centric mobility framework that provides handover for macro-mobility on handheld devices. The framework is designed for mobile- controlled handover and does not require modification of the Internet infrastructure. The end-users are so able to control the roaming process governed by user considerations in addition to business objectives. To achieve seamless mobility UDP tunneling is used as a basis for the handover process. Additionally, measurements are performed on the tunnels to acquire Quality of Service (QoS) metrics and hence serve for roaming decision making processes.

  • 188. Vogeleer, Karel De
    et al.
    Ickin, Selim
    Fiedler, Markus
    Erman, David
    Popescu, Adrian
    Estimation of Quality of Experience in 3G Networks with the Mahalanobis Distance2011Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Quality of Experience is a parameter used to express the relationship between Quality of Service and the satisfaction of network service subscribers. The modeling of Quality of Experience demands for solving a multidimensional problem. In this paper, we present a Quality of Experience analysis of streaming videos. Related to this, we show that we can reduce the dimensions of the Quality of Experience modeling with the help of Principle Component Analysis techniques. We demonstrate that for our data set the Zero Throughput Time and the Packet Delay Variation are enough to get a picture of the state of the network. We further calculate the Mahalanobis distance to analyze the outliers in the data set. We illustrate that for our data set the 97.5% quantile for the Mahalanobis distance is a good threshold that indicates low user perception. We also advocate the use of robust statistics in the analysis of Quality of Experience as we are dealing with contaminated data sets.

  • 189.
    Vogeleer, Karel De
    et al.
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Popescu, Adrian
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Fiedler, Markus
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Erman, David
    Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation.
    Content dependency of the traffic control in the darwin streaming server2012Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The Darwin Streaming Server employs stream thinning and transmission rate adaptation for traffic and congestion control. We investigate the relation of video content with the stream thinning and transmission rate adaptation process under 3GPP-adaptation. We observe that stream thinning is not only initiated upon fluctuation of network properties, but sometimes also upon the content of the streamed video. Moreover, we show that in extreme situations the video transmission is halted based merely on content dependent properties reflected in the RTSP feedback. This may have adverse consequences for the user experience. We put forward alterations to the 3GPP-adaptation traffic control of the Darwin Streaming Server that controls the stream thinning process. The alterations aim to avoid video freezes as a result of video content dependent properties. The results show that the probability of an interrupt-free playback is lower for the alterations than for the default streaming server algorithms.

  • 190. Wac, Katarzyna
    et al.
    Arlos, Patrik
    Blekinge Tekniska Högskola, Sektionen för teknik, Avdelningen för telekommunikationssystem.
    Fiedler, Markus
    Blekinge Tekniska Högskola, Sektionen för teknik, Avdelningen för telekommunikationssystem.
    Chevul, Stefan
    Blekinge Tekniska Högskola, Sektionen för teknik, Avdelningen för telekommunikationssystem.
    Isaksson, Lennart
    Blekinge Tekniska Högskola, Sektionen för teknik, Avdelningen för telekommunikationssystem.
    Bults, Richard
    Accuracy Evaluation of Application-level Performance Measurements2007Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In many cases, application-level measurements can be the only way for an application to evaluate and adapt to the performance offered by the underlying networks. Applications perceive heterogeneous networking environments spanning over multiple administrative domains as black boxes being inaccessible for lower-level measurement instrumentation. However, application-level measurements can be inaccurate and differ significantly from the lower-level ones, amongst others due to the influence of the protocol stacks. In this paper we quantify and discuss such differences using the DPMI, with Measurement Points instrumented with DAG 3.5E cards for reference link-level measurements. We shed light on various impacts on timestamp accuracy of application-level measurements. Moreover, we quantify the accuracy of generating traffic with constant inter-packet-time. The latter is essential for an accurate emulation of application-level streaming traffic and thus for obtaining realistic end-to-end performance measurements.

  • 191. Wac, Katarzyna
    et al.
    Fiedler, Markus
    Bults, Richard
    Hermens, Hermie
    Estimations of Additional Delays for Mobile Application Data from Comparative Output-Input Throughput Analysis2010Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Mobile devices with ever increasing functionality are an important driving force behind innovative mobile applications that enrich our daily life. The ubiquitous availability of wireless data communication networks is an additional driving force. Their ability to support application data flows is one of the performance criteria for successful mobile application deployment. Nevertheless, the quantitative impact of this performance is unknown and practically infeasible to determine real-time at the application-level due to mobile device resource constraints. We research practical methods for measurements based application-level performance evaluation of data communication networks that support mobile application data flows. In this paper, we propose the lightweight Comparative Output-Input Analysis (COIA) method that estimates additional delay at observation time scale of interest (e.g. 1 s) induced on the application data flow. The additional delay (Tadd) is the amount of delay exceeding non-avoidable, minimal end-to-end data delay caused by data communication network propagation and transmission delays. We distinguish five COIA methods to estimate Tadd. We validate their accuracy with measurements obtained from an m-health application - health telemonitoring application provided by the MobiHealth system. Despite their simplicity, our methods prove to be accurate in relation to the observation time scale of interest, and robust under a variety of network conditions. The methods offer novel insights into the impact of data communication network performance on the application data flow delay behaviour.

  • 192. Wac, Katarzyna
    et al.
    Ickin, Selim
    Hong, Jin-Hyuk
    Janowski, Lucjan
    Fiedler, Markus
    Dey, Anind K.
    Studying the experience of mobile applications used in different contexts of daily life2011Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Mobile applications and services increasingly assist us in our daily life situations, fulfilling our needs for information, communication, entertainment or leisure. However, user acceptance of a mobile application depends on at least two conditions; the application’s perceived Quality of Experience (QoE) and the appropriateness of the application to the user’s situation and context. Yet, there is generally a weak understanding of a mobile user’s QoE and the factors influencing it. The mobile user’s experience is related to the Quality of Service (QoS) provided by the underlying service and network infrastructures, which provides a starting point for our work. We present “work- in-progress” results from an ongoing study of Android phone users. In this study, we aim to derive and improve understanding of their QoE in different situations and daily life environments. In particular, we evaluate the user’s qualitative QoE for a set of widely used mobile applications in the users’ natural environments and different contexts, and we analyze this experience and its relation to the underlying quantitative QoS. In our approach we collect both QoE and QoS measures through a combination of user, application and network input from mobile phones. We present initial data acquired in the study and derived from that, a set of preliminary implications for mobile applications design.

  • 193.
    Yao, Yong
    et al.
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för datalogi och datorsystemteknik.
    Popescu, Adrian
    Blekinge Tekniska Högskola.
    Fiedler, Markus
    Blekinge Tekniska Högskola.
    Ljung, Rickard
    Sony Mobile Communications, SWE.
    On the Performance of Video Streaming in Energy-Aware Wireless Mesh Networks2017Inngår i: European Conference on Networks and Communications (EuCNC) 2017, IEEE, 2017Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Mobile multimedia has today become a promising application for end users and service providers. With reference to the existing systems for mobile communications, this application further demands for solving several technical problems, especially regarding video streaming over wireless networks. An interesting approach is in form ofWireless Mesh Network (WMN) based networks, where the individual video flows operate in an end-to-end (e2e) manner along a particular networking scenario including several mesh routers. That means, a particular mesh router may be traversed by multiple video flows. This situation may become even more complicated in the case of a large amount of packet retransmissions, which may deteriorate the performance of video flows. To investigate this problem, a two-level Modulated Markov Poisson Process (MMPP) based queueing model is built up and the transport performance of e2e video streaming in WMN based mobile multimedia system is analysed. Four metrics are used to study the system performance, namely e2e throughput, e2e delay, e2e error-rate and traffic-related energy consumption. Numerical analysis and evaluation studies are done. Based on the reported results, two different solutions are suggested and discussed with regard to the trade-off among these metrics.

  • 194.
    Zepernick, Hans-Jürgen
    et al.
    Blekinge Tekniska Högskola, Sektionen för teknik, Avdelningen för signalbehandling.
    Fiedler, Markus
    Blekinge Tekniska Högskola, Sektionen för teknik, Avdelningen för telekommunikationssystem.
    Lundberg, Lars
    Blekinge Tekniska Högskola, Sektionen för teknik, Avdelningen för programvarusystem.
    Pettersson, Mats
    Blekinge Tekniska Högskola, Sektionen för teknik, Avdelningen för signalbehandling.
    Quality of Experience Based Cross-Layer Design of Mobile Video Systems2008Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper introduces and discusses quality of experience based cross-layer design of mobile video systems as a means of providing technologies for jointly analyzing, adopting, and optimizing system quality. The many benefits of our novel approaches over traditional concepts will range from efficient video processing techniques over advanced real-time scheduling algorithms, to networking and service level management techniques. This will lead to better service quality and resource utilization in mobile video systems.

  • 195. Zinner, T.
    et al.
    Hossfeld, T.
    Fiedler, Markus
    Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, Institutionen för kommunikationssystem.
    Liers, F.
    Volkert, T.
    Kohndoker, R.
    Schatz, R.
    Requirement driven prospects for realizing user-centric network orchestration2015Inngår i: Multimedia tools and applications, ISSN 1380-7501, E-ISSN 1573-7721, Vol. 74, nr 2, s. 413-437Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The Internet's infrastructure shows severe limitations when an optimal end user experience for multimedia applications should be achieved in a resource-efficiently way. In order to realize truly user-centric networking, an information exchange between applications and networks is required. To this end, network-application interfaces need to be deployed that enable a better mediation of application data through the Internet. For smart multimedia applications and services, the application and the network should directly communicate with each other and exchange information in order to ensure an optimal Quality of Experience (QoE). In this article, we follow a use-case driven approach towards user-centric network orchestration. We derive user, application, and network requirements for three complementary use cases: HD live TV streaming, video-on-demand streaming and user authentication with high security and privacy demands, as typically required for payed multimedia services. We provide practical guidelines for achieving an optimal QoE efficiently in the context of these use cases. Based on these results, we demonstrate how to overcome one of the main limitations of today's Internet by introducing the major steps required for user-centric network orchestration. Finally, we show conceptual prospects for realizing these steps by discussing a possible implementation with an inter-network architecture based on functional blocks.

  • 196. Zinner, Thomas
    et al.
    Hossfeld, Tobias
    Minhas, Tahir Nawaz
    Fiedler, Markus
    Controlled vs. Uncontrolled Degradations of QoE: The Provisioning-Delivery Hysteresis in Case of Video2010Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper applies the recently proposed provisioning-delivery hysteresis for Quality of Experience (QoE) to the case of video. The study is based on evaluations using the Structural Similarity Metric (SSIM) for different versions of a video in terms of resolution on one hand, and suffering from different packet loss ratios on the other hand. Upon translation of the SSIM into MOS, the QoE plotted versus the effective throughput shows the predicted behaviour: a controlled quality and throughput reduction leads to a better user perceived quality than the quality degradation due to packet loss. The results clearly quantify the necessity to control quality, instead of "getting hit" in an uncontrolled way.

1234 151 - 196 of 196
RefereraExporteraLink til resultatlisten
Permanent link
Referera
Referensformat
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf