Change search
Refine search result
1 - 16 of 16
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Minhas, Tahir Nawaz
    Blekinge Institute of Technology, School of Computing.
    Network Impact on Quality of Experience of Mobile Video2012Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    To an end user, Quality of Experience (QoE) matters more than Quality of Service (QoS) because she is the owner of her experience, which is the result of her perception. In recent times, QoE got increasingly much attention from service providers, operators, manufacturers and researchers. Amongst others, they are interested to know how the users perceive the quality of multimedia streaming and how to predict the QoE by measuring network performance parameters. Below the network layer, different access networks can be used, but the internet and transport layers remain the same for everyone on best-effort internet. We highlight a set of possible factors that are contributing towards the QoE, from network via transport to application layer, including applications, codecs, middleware and devices. To investigate the relationship of QoS and QoE, emulation-based experiments were designed. For the purpose of emulation, different shapers are in use by the research community. We selected three popular shapers, NetEm, NISTnet and KauNet, and investigated their emulation capabilities with focus on delay, delay variation and bit rate in order to be able to select the best-suited shaper for future use. Then, we studied the effect of QoS parameters on mobile video QoE. To evaluate the video QoE, user tests were conducted. We observe a much larger sensitivity of users to freezes and their placement within the video than what is predicted by an objective video quality assessment tool that is recommended by the standardisation organization ITU. Furthermore, we investigated the role of codec and device on QoE in view of network-induced problems.

  • 2. Minhas, Tahir Nawaz
    et al.
    Fiedler, Markus
    Impact of Disturbance Locations on Video Quality of Experience2011Conference paper (Refereed)
    Abstract [en]

    Quality of experience is getting the attention of the research community as well as the industry. In case of real-time streaming, packet loss, delay and jitter degrades the video quality. The player buffer can be emptied due to long delay, which freezes video at playout, while resuming the streaming video content causes jumps to current location. There is the question, how user is going to react to such kind of artifacts with respect to location where they arise. We collected user ratings for videos showing the artifacts due to delay variation as well as freezes and jumps at different locations. We also verified these results with Perceptual Evaluation of Video Quality (PEVQ) application. For delay and delay variation case, the PEVQ results are aligning to the human rating, but both differ in freeze-and-jump case. The users' responses in case of freeze-and-jump shows interesting results with respect to location.

  • 3.
    Minhas, Tahir Nawaz
    et al.
    Blekinge Institute of Technology, School of Computing.
    Fiedler, Markus
    Blekinge Institute of Technology, School of Computing.
    Quality of Experience Hourglass Model2013Conference paper (Refereed)
    Abstract [en]

    Recently, user perception has been receiving increasingly much attention of service providers, operators, manufactures and researchers. They are interested to know how the users perceive the quality of multimedia streaming services. To avoid the fatigue of subjective testing, they are interested to model the Quality of Experience (QoE) based on Quality of Service (QoS) and other measurable parameters. However, these parameters to estimate the QoE may differ per service. In this paper, we propose a conceptual model of QoE in parallel with the classical internet architecture hourglass model. Moreover conditions are highlighted under which QoE can be evaluated objectively from QoS without entailing other factors. The main is goal to understand the factors that are playing a significant role for QoE. We also discuss and explain the role of the application on QoE.

  • 4. Minhas, Tahir Nawaz
    et al.
    Fiedler, Markus
    Arlos, Patrik
    Quantification of Packet Delay Variation through the Coefficient of Throughput Variation2010Conference paper (Refereed)
    Abstract [en]

    Packet delay variation plays an important role in network performance degradation and affects the user-perceptual quality, especially in case of real-time services such as video streaming, VoIP etc. Lightweight methods for detecting network performance issues are desirable as compared to taskintensive measurement and analysis. On this background, this paper discusses the applicability of the Coefficient of Throughput Variation (CoTV) to quickly and reliably detect bottleneck behavior between two arbitrary points in a network. The CoTV can be used as a Reduced Reference Metric. It is relatively simple to calculate, compare and interpret, yet powerful to provide control feedback when facing changes in network performance. In this paper, we demonstrate above mentioned properties of the CoTV through a formula relating it to the sample interval of the throughput and the variability of the delay. The latter is shown to be detectable on time scales that are significantly larger than that of the variability itself. This observation is a key enabler for reducing the load on the device that performs the analysis due to the possibility to use large sample intervals. We also describe how difference and ratio of CoTV at outlet and inlet can be used to identify network performance issues.

  • 5.
    Minhas, Tahir Nawaz
    et al.
    Blekinge Institute of Technology, School of Computing.
    Fiedler, Markus
    Blekinge Institute of Technology, School of Computing.
    Shaikh, Junaid
    Blekinge Institute of Technology, School of Computing.
    Arlos, Patrik
    Blekinge Institute of Technology, School of Computing.
    Evaluation of throughput performance of traffic shapers2011Conference paper (Refereed)
    Abstract [en]

    Traffic shapers are used by researchers to emulate the behavior of networks and applications in test environments, typically with user-defined traffic shaping parameters such as throughput and loss. Also, traffic shapers are used for the enforcement of SLA, so they are of interest for Internet Service Providers. However, output given by traffic shapers may not be as accurate as desired. Therefore, it is important to assess the accuracy of the implementation of traffic shapers. In this paper, we evaluate two traffic shapers with regard to the performance of their throughput shaping. For this evaluation, traces were collected. The properties of the resulting throughput at the outlet of the shaper are compared to the properties of the throughput at the inlet in combination with the preset shaper parameters. In this sense, we also compare shapers installed on Advance Micro Devices (AMD) and Intel platforms, and we use different PDU sizes and load levels to test the influence of those parameters on the shaping. We are furthermore able to deduct internal shaper parameters such as packet rate and buffer size from our measurements, and we analyse the statistical properties of the packet departure process. The extensive measurement results in this paper allow for a detailed assessment of the question whether the shaper performance is up to mark for a desired timescale. In general, the performance of both shapers and hardware platforms can be considered satisfactory on the investigated time scales between 1 ms and 1 s, with a slight advantage for NetEm on AMD.

  • 6.
    Minhas, Tahir Nawaz
    et al.
    Blekinge Institute of Technology, School of Computing.
    Lagunas, Oziel Gonzales
    Arlos, Patrik
    Blekinge Institute of Technology, School of Computing.
    Fiedler, Markus
    Blekinge Institute of Technology, School of Computing.
    Mobile video sensitivity to packet loss and packet delay variation in terms of QoE2012Conference paper (Refereed)
    Abstract [en]

    With the growth of the mobile internet, the popularity of multimedia services and applications have increased rapidly. As a result, end-users become quality-conscious. To fulfill the users' expectations, the study of quality of experience (QoE) is becoming very important for both researchers and service providers. This paper analyses the impact on perceived quality of received videos encoded with the H.264 baseline profile, which is suitable for mobile video, and streamed through an emulated network with packet loss and packet delay variation. To evaluate the video QoE, tests are conducted on a mobile device and on a laptop. The users' responses show that the baseline profile of H.264 is very sensitive to packet loss and packet delay variation. Moreover, there is no considerable impact on users' perception either test is conducted on the mobile device or on the laptop by playing the same resolution video.

  • 7.
    Minhas, Tahir Nawaz
    et al.
    Blekinge Institute of Technology, Faculty of Computing, Department of Communication Systems.
    Shahid, Muhammad
    Blekinge Institute of Technology, Faculty of Engineering, Department of Applied Signal Processing.
    Lövström, Benny
    Blekinge Institute of Technology, Faculty of Engineering, Department of Applied Signal Processing.
    Rossholm, Andreas
    Blekinge Institute of Technology, Faculty of Engineering, Department of Applied Signal Processing.
    Zepernick, Hans-Jürgen
    Blekinge Institute of Technology, Faculty of Computing, Department of Communication Systems.
    Fiedler, Markus
    Blekinge Institute of Technology, Faculty of Computing, Department of Communication Systems.
    QoE rating performance evaluation of ITU-T recommended video quality metrics in the context of video freezes2016In: Australian Journal of Electrical and Electronics Engineering, ISSN 1448-837X, Vol. 13, no 2, p. 122-131Article in journal (Refereed)
    Abstract [en]

    In real-time video streaming, video quality can be degraded due to network performance issues. Among other artefacts, video freezing and video jumping are factors that influence user experience. Service providers, operators and manufacturers are interested in evaluating the quality of experience (QoE) objectively because subjective assessment of QoE is expensive and, in many user cases, subjective assessment is not possible to perform. Different algorithms have been proposed and implemented in this regard. Some of them are in the recommendation list of the ITU Telecommunication Standardization Sector (ITU-T). In this paper, we study the effect of the freezing artefact on user experience and compare the mean opinion score of these videos with the results of two algorithms, the perceptual evaluation of video quality (PEVQ) and temporal quality metric (TQM). Both metrics are part of the ITU-T Recommendation J.247 Annex B and C. PEVQ is a full-reference video quality metric, whereas TQM is a no-reference quality metric. Another contribution of this paper is the study of the impact of different resolutions and frame rates on user experience and how accurately PEVQ and TQM measure varying frame rates.

  • 8.
    Minhas, Tahir
    et al.
    Blekinge Institute of Technology, School of Computing.
    Shahid, Mohammad
    Blekinge Institute of Technology, School of Engineering, Department of Electrical Engineering.
    Rossholm, Andreas
    Lövström, Benny
    Blekinge Institute of Technology, School of Engineering, Department of Electrical Engineering.
    Zepernick, Hans-Jürgen
    Blekinge Institute of Technology, School of Computing.
    Fiedler, Markus
    Blekinge Institute of Technology, School of Computing.
    Assessment of the Rating Performance of ITU-T Recommended Video Quality Metrics in the Context of Video Freezes2013Conference paper (Refereed)
    Abstract [en]

    Video streaming and multimedia applications are getting popular with the growth of networks. In real-time video streaming, video quality can be degraded due to network performance issues. Among other artifacts, freezing and frame dropping are factors that influence user experience. Service providers, operators, and researchers are interested to measure the Quality of Experience objectively. Different algorithms have been proposed and implemented in this regard. Some of them are in the recommendation list of the ITU Telecommunication Standardization Sector (ITU-T). In this paper, we study the effect of the freezing artifact on user experience and compare the mean opinion score (MOS) of these videos with the results of two algorithms, Perceptual Evaluation of Video Quality (PEVQ) and Temporal Quality Metric, both being part of ITU-T Recommendation J.247 Annex B and C, respectively. Another contribution of this paper is the investigation of the impact of different resolutions and frame rates on user experience.

  • 9.
    Molléri, Jefferson Seide
    et al.
    Blekinge Institute of Technology, Faculty of Computing, Department of Software Engineering.
    Ali, Nauman bin
    Blekinge Institute of Technology, Faculty of Computing, Department of Software Engineering.
    Petersen, Kai
    Blekinge Institute of Technology, Faculty of Computing, Department of Software Engineering.
    Minhas, Tahir Nawaz
    Chatzipetrou, Panagiota
    Blekinge Institute of Technology, Faculty of Computing, Department of Software Engineering.
    Teaching students critical appraisal of scientific literature using checklists2018In: ACM International Conference Proceeding Series, Association for Computing Machinery , 2018, p. 8-17Conference paper (Refereed)
    Abstract [en]

    Background: Teaching students to critically appraise scientific literature is an important goal for a postgraduate research methods course. Objective: To investigate the application of checklists for assessing the scientific rigor of empirical studies support students in reviewing case study research and experiments. Methods:We employed an experimental design where 76 students (in pairs) used two checklists to evaluate two papers (reporting a case study and an experiment) each. We compared the students' assessments against ratings from more senior researchers. We also collected data on students' perception of using the checklists. Results: The consistency of students' ratings and the accuracy when compared to ratings from seniors varied. A factor seemed to be that the clearer the reporting, the easier it is for students to judge the quality of studies. Students perceived checklist items related to data analysis as difficult to assess. Conclusion: As expected, this study reinforces the needs for clear reporting, as it is important that authors write to enable synthesis and quality assessment. With clearer reporting, the novices performed well in assessing the quality of the empirical work, which supports its continued use in the course as means for introducing scientific reviews. © 2018 Association for Computing Machinery.

  • 10.
    Nawaz, Omer
    et al.
    Blekinge Institute of Technology, Faculty of Computing, Department of Communication Systems. Blekinge Inst Technol, Dept Commun Syst, Karlskrona, Sweden..
    Minhas, Tahir Nawaz
    Blekinge Institute of Technology, Faculty of Computing, Department of Communication Systems. Blekinge Inst Technol, Dept Commun Syst, Karlskrona, Sweden..
    Fiedler, Markus
    Blekinge Institute of Technology, Faculty of Computing, Department of Communication Systems. Blekinge Institute of Technology, School of Engineering, Department of Telecommunication Systems. Blekinge Institute of Technology, School of Computing. Blekinge Inst Technol, Dept Commun Syst, Karlskrona, Sweden..
    Optimal MTU for Realtime Video Broadcast with Packet Loss - A QoE Perspective2014In: 2014 9TH INTERNATIONAL CONFERENCE FOR INTERNET TECHNOLOGY AND SECURED TRANSACTIONS (ICITST), IEEE , 2014, p. 396-401Conference paper (Refereed)
    Abstract [en]

    Multimedia applications have become the prime source of Internet traffic in recent years due to high bandwidth offered by almost all access mechanisms. This highlights the need of intense research efforts to improve the already demanding user perception levels for high-performance video delivery networks. Quality of Experience (QoE) based metrics are often used to quantify user satisfaction levels regarding an application or service. In this paper, we have analyzed the impact of variable frame sizes at link layer with different packet loss scenarios to evaluate the performance degradation of H.264 based live video streams from the end user perspective using subjective tests. We have focused on both subjective and objective quantitative measures to analyze the myth that smaller packets provide better quality in error-prone networks. We found that this assumption may not be true for some cases with a considerable packet loss ratio. Moreover, we observed that full-reference video assessment software like PEVQ predicts QoE to an acceptable extent, which allows cutting cost and effort coming with subjective evaluations. Keywords-Quality of Experience, Multimedia communication, Streaming media

  • 11.
    Nawaz, Omer
    et al.
    Blekinge Institute of Technology, Faculty of Computing, Department of Technology and Aesthetics.
    Minhas, Tahir Nawaz
    Blekinge Institute of Technology, Faculty of Computing, Department of Technology and Aesthetics.
    Fiedler, Markus
    Blekinge Institute of Technology, Faculty of Computing, Department of Technology and Aesthetics.
    QoE based comparison of H.264/AVC and WebM/VP8 in an error-prone wireless network2017In: Proceedings of the IM 2017 - 2017 IFIP/IEEE International Symposium on Integrated Network and Service Management / [ed] Chemouil P.,Simoes P.,Madeira E.,Secci S.,Monteiro E.,Gaspary L.P.,dos Santos C.R.P.,Charalambides M., Institute of Electrical and Electronics Engineers (IEEE), 2017, p. 1005-1010Conference paper (Refereed)
    Abstract [en]

    Quality of Experience (QoE) management is a prime topic of research community nowadays as video streaming, online gaming and security applications are completely reliant on the network service quality. Moreover, there are no standard models to map Quality of Service (QoS) into QoE. HTTP media streaming is primarily used for such applications due to its coherence with the Internet and simplified management. The most common video codecs used for video streaming are H.264/AVC and Google's VP8. In this paper, we have analyzed the performance of these two codecs from the perspective of QoE. The most common end-user medium for accessing video content is via home based wireless networks. We have emulated an error-prone wireless network with different scenarios involving packet loss, packet delay and delay variation. The focus of this paper is evaluating the end user satisfaction with the multimedia content by subjective assessment using Mean Opinion Score (MOS). We have observed the overall superiority of H.264/AVC but the VP8 codec strongly gains ground in highly error-prone networks in terms of user satisfaction. © 2017 IFIP.

  • 12.
    Shaikh, Junaid
    et al.
    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.
    Minhas, Tahir Nawaz
    Blekinge Institute of Technology, School of Computing.
    Collange, Denis
    Classification of TCP Connection Termination Behaviors for Mobile Web2011Conference paper (Refereed)
    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.

  • 13.
    Shaikh, Junaid
    et al.
    Blekinge Institute of Technology, School of Computing.
    Fiedler, Markus
    Blekinge Institute of Technology, School of Computing.
    Minhas, Tahir Nawaz
    Blekinge Institute of Technology, School of Computing.
    Arlos, Patrik
    Blekinge Institute of Technology, School of Computing.
    Collange, Denis
    Inferring User-perceived Performance of Network by Monitoring TCP Interruptions2012In: Network Protocols and Algorithms, ISSN 1943-3581, E-ISSN 1943-3581, Vol. 4, no 2, p. 49-67Article in journal (Refereed)
    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.

  • 14.
    Shaikh, Junaid
    et al.
    Blekinge Institute of Technology, School of Computing.
    Fiedler, Markus
    Blekinge Institute of Technology, School of Computing.
    Minhas, Tahir Nawaz
    Blekinge Institute of Technology, School of Computing.
    Arlos, Patrik
    Blekinge Institute of Technology, School of Computing.
    Collange, Denis
    Passive Methods for the Assessment of User-perceived Quality of Delivery2011Conference paper (Refereed)
    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.

  • 15.
    Shaikh, Junaid
    et al.
    Blekinge Institute of Technology, School of Computing.
    Minhas, Tahir Nawaz
    Blekinge Institute of Technology, School of Computing.
    Arlos, Patrik
    Blekinge Institute of Technology, School of Computing.
    Fiedler, Markus
    Blekinge Institute of Technology, School of Computing.
    Evaluation of delay performance of traffic shapers2010Conference paper (Refereed)
    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.

  • 16. Zinner, Thomas
    et al.
    Hossfeld, Tobias
    Minhas, Tahir Nawaz
    Fiedler, Markus
    Controlled vs. Uncontrolled Degradations of QoE: The Provisioning-Delivery Hysteresis in Case of Video2010Conference paper (Refereed)
    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.

1 - 16 of 16
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf