Pour avoir une idée sur la qualité du réseau, la majorité des acteurs concernés (opérateurs réseau, fournisseurs de service) se basent sur la Qualité de Service (Quality of Service). Cette mesure a montré des limites et beaucoup d'efforts ont été déployés pour mettre en place une nouvelle métrique qui reflète, de façon plus précise, la qualité du service offert. Cette mesure s'appelle la qualité d'expérience (Quality of Experience). La qualité d'expérience reflète la satisfaction de l'utilisateur par rapport au service qu'il utilise. Aujourd'hui, évaluer la qualité d'expérience est devenu primordiale pour les fournisseurs de services et les fournisseurs de contenus. Cette nécessité nous a poussés à innover et concevoir des nouvelles méthodes pour estimer la QoE. Dans cette thèse, nous travaillons sur l'estimation de la QoE (1) dans le cas des communications Voix sur IP et (2) dans le cas des services de diffusion Vidéo sur IP. Nous étudions les performances et la qualité des codecs iLBC, Speex et Silk pour la VoIP et les codecs MPEG-2 et H.264/SVC pour la vidéo sur IP. Nous étudions l'impact que peut avoir la majorité des paramètres réseaux, des paramètres sources (au niveau du codage) et destinations (au niveau du décodage) sur la qualité finale. Afin de mettre en place des outils précis d'estimation de la QoE en temps réel, nous nous basons sur la méthodologie Pseudo-Subjective Quality Assessment. La méthodologie PSQA est basée sur un modèle mathématique appelé les réseaux de neurones artificiels. En plus des réseaux de neurones, nous utilisons la régression polynomiale pour l'estimation de la QoE dans le cas de la VoIP.

Dynamic Adaptive Streaming over HTTP (DASH) is a convenient approach to transfer videos in an adaptive and dynamic way to the user. Therefore, this system makes best use of the bandwidth available. In this thesis, we investigate Dynamic Adaptive Streaming over HTTP (DASH) based on data collected from the lab experiments and user’s experiments. The objectives include investigation of how three different DASH players behave at different network conditions and up to which limit the players are tolerating the disturbances. We summarized the outcome of lab experiments on DASH at different adverse conditions and checked the lab results with user quality of experience at different adverse conditions to see up to which extent the users could tolerate the disturbances in different DASH players.

Streaming multimedia over the Internet is omnipresent but still in its infancy, specifically when it comes to theadaptation based on bandwidth/throughput measurements, clients competing for limited/shared bandwidth, and thepresence of a caching infrastructure. Nowadays the streaming infrastructure is existing over-the-top (OTT).Interestingly, these services are all delivered over-the-top of the existing networking infrastructure using the HypertextTransfer Protocol (HTTP) which resulted in the standardization of MPEG Dynamic Adaptive Streaming over HTTP(DASH).Video traffic is over 80% of the total internet traffic. Since Dynamic adaptive streaming over HTTP hasemerged it has a popular technique for video streaming on the internet. DASH allows the video player to adapt thebitrate according to the network conditions. DASH streaming client receives a manifest file, downloaded the referredvideo segments over HTTP, and play them back seamlessly emulated video streaming. This introduces latency of atleast one segment duration which decreases the quality of the user experience. In order to improve users over allQuality of Experience(QoE) a large number of adaptaion schemes were introduced to DASH.With such an importance of QoE on DASH, this thesis work investigates user acceptability of different DASHplayers. These players are exposed to different network conditions and the user analysis is given for each of thestreaming dash video for each player. The results of this thesis work include the analysis of the user rating for threedifferent players (Dash.js, GPAC and Shaka). The conclusion of this thesis is given by the quality of experience of thevideo streaming by the users which concludes that the Shaka player is preferred by the users compared to the othertwo players.

This diploma thesis focuses on the issue of evaluation VoIP services (from the perspective of QoE) and their quality in university network. It includes theoretical basics of VoIP testing, principals of QoS, and also overview of QoE/MOS measurement methods. Next part describes the test bed and methodology used for measurements and evaluating of results. Site survey results and VoIP quality measurement are evaluated at the end, followed by recommendations that can lead to better VoIP quality in MENDELU wireless network.

The Industrial Internet of Things (IIoT) is one of the key technologies of Industry 4.0 thatwill be an integral part of future smart and sustainable production. The current constitutedmodels for estimating Quality of Experience (QoE) are mainly targeting the multimediasystems. Present models for evaluating QoE, specifically leveraged by the expensivesubjective tests, are not applicable for IIoT applications. This work triggers the discussionon defining the QoE domain for IIoT services and applications. Industry-specific KPIs areproposed to assure QoE by linking business and technology domains. Tele-remote miningmachines are considered as a case study for developing the QoE model by taking intoaccount key challenges in QoE domain. As a result, QoE layered model is proposed, whichas an outcome predicts the QoE of IIoT services and applications in a form of pre-definedIndustrial KPIs. Moreover, software tool and analytical model is proposed to be used as anevaluation method for certain traffic types in the developed model.

Background: In the recent years, the focus of research has shifted to Quality of Experience(QoE) to maintain the user satisfaction levels and fulfill their expectations of the serviceoffered. Numerous work has been established in finding the relationship between the networklayer and QoE. But, it is fact that the transport layer is much closer to the end-user than thenetwork layer in the TCP/IP communication protocol suite. Thus, any changes in the degreeof satisfaction or degree of annoyance are directly reflected onto transport layer than on thenetwork layer. So, it becomes more significant to study the behavior of user satisfaction inrelation to transport layer than the network layer. Objectives: This research is to relate the behavior of TCP to QoE. The main considerations tobridge the gap between them are: (a) Analyzing the effects of using different versions of TCPon server and client side, (b) Monitoring and analyzing the intensity of TCP traffic in thereverse direction and (c) Investigating TCP control flags from client to server. Methods: QoE related parameters used in this research are: (a) Quality of video i.e., MOS, (b)Degree of disturbance caused by initial delay, (c) Degree of disturbance caused by jerkinessand (d) Degree of disturbance caused by freezes. Effects of network impairments like delay,jitter and packet loss are considered in this research. NetEm is used as the traffic emulationsoftware to shape the traffic. The packet capture analysis of traffic exchange is implementedusing tcpdump. Results and Conclusions: The aim of this research is to provide a passive-estimation methodto assess the user perceived performance. The results of this research provide valuablecontribution to service providers/operators to note the early warning signals from TCP reversetraffic to evaluate the decrease of user satisfaction level and try to cope or/and recover fromimpairments in the network. This research also provides a scope for future researchers toinvestigate other protocols both in transport and application layers.

Submitted by João Arthur Martins (joao.arthur@ufpe.br) on 2015-03-11T18:40:22Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertaçao Lorena Marques.pdf: 2473408 bytes, checksum: ae5cba07c563d08350f8ddc5184cffee (MD5) / Approved for entry into archive by Daniella Sodre (daniella.sodre@ufpe.br) on 2015-03-13T13:10:17Z (GMT) No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertaçao Lorena Marques.pdf: 2473408 bytes, checksum: ae5cba07c563d08350f8ddc5184cffee (MD5) / Made available in DSpace on 2015-03-13T13:10:17Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertaçao Lorena Marques.pdf: 2473408 bytes, checksum: ae5cba07c563d08350f8ddc5184cffee (MD5) Previous issue date: 2013-02-25 / FACEPE / A crescente disponibilidade de acesso sem fio através de diferentes tecnologias (e.g., IEEE 802.11, IEEE 802.16 e 3G/UMTS) e o aumento do número de dispositivos com suporte a múltiplas interfaces heterogêneas possibilitam uma gama de oportunidades de conectividade sem fio aos usuários. Tradicionalmente, para este cenário, tem-se proposto algoritmos, protocolos e arquiteturas para a escolha da melhor rede de acordo com o perfil do usuário, característica da aplicação e da rede. Outra possibilidade de pesquisa, ainda não tão explorada no âmbito sem fio, é a distribuição de carga e conteúdo através de múltiplos caminhos simultâneos. Esta característica é conhecida como multihoming e pode dispor redundância de caminhos, oferecendo, dessa forma, certo grau de confiabilidade na rede. O grande desafio para implantação do multihoming em redes móveis heterogêneas decorre da instabilidade que esses ambientes possuem. O problema se agrava quando existem várias interfaces tentando se comunicar simultaneamente. O CMT (Concurrent Multipath Transfer) usa a característica multihoming do SCTP (Stream Control Transmission Protocol) para transmitir dados através de múltiplos caminhos fim-a-fim simultaneamente. No entanto, o CMT não possui um bom desempenho em redes com diferentes características, especialmente em se tratando de vídeo. Esta dissertação propõe o aCMT-UC (Adaptive CMT-User Centric), uma solução baseada em multihoming/centrada no usuário para a distribuição de carga em redes heterogêneas sem fio, tornando o CMT adaptável à dinâmica dos caminhos. O aCMT-UC prioriza os quadros de vídeo mais importantes que são transmitidos pelo melhor caminho sem fio. A distribuição de carga e priorização de vídeo são realizadas através da atribuição dinâmica de diferentes pesos para os caminhos sem fio, de acordo com um procedimento inteligente baseado em Lógica Fuzzy. Foram avaliadas métricas de Qualidade de Serviço e Experiência (QoS/QoE) em uma rede formada pelas tecnologias IEEE 802.11, IEEE 802.16 e 3G/UMTS em um simulador de redes (ns-2). Os resultados obtidos demonstram a eficácia da proposta em garantir QoS, bem como, o suporte adequado aos requisitos de tráfego de vídeo.

Made available in DSpace on 2014-06-12T16:00:39Z (GMT). No. of bitstreams: 2 arquivo6834_1.pdf: 2552234 bytes, checksum: ff18190fd071f2e26f6470e29f084e5a (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2011 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Com a crescente popularidade das redes sem fio e as tecnologias Wi-Fi (Wireless Fidelity), WiMAX (Worldwide Interoperability for Microwave Access), surgiu a necessidade de se promover uma convergência entre elas, visando oferecer ao usuário diversas oportunidades de conectividade e a possibilidade de estabelecer uma comunicação sem interrupções. Neste contexto, o trabalho tem como objetivo propor um mecanismo de seleção de rede baseado na qualidade de experiência do usuário (QoE - Quality of Experience). A partir dos resultados coletados nas simulações realizadas no Network Simulator (ns-2), foi construída uma base de dados com o histórico de valores obtidos com a métrica de Relação Sinal/Ruído (PSNR Peak Signal Noise Ratio), utilizada com o auxilio do protocolo IEEE 802.21 para a execução da tomada de decisão de handover. Dentre as contribuições deste trabalho, a principal consiste na seleção de redes heterogêneas em que a decisão de handover considera a percepção do usuário, com uso da métrica de QoE. Os resultados demonstram que a decisão de handover baseada em QoE reflete no aumento de 15 % na qualidade do vídeo

Currently, user satisfaction is becoming one of the major concerns for the service provider in accommodating user demand. This paper evaluates the user’s perception (Quality of Experience, QoE) of the increasing and decreasing response times (Quality of Service, QoS), in particular a login to web login page by the implementation of Mean Opinion Score (MOS). By comparing the results to user perception of web login performance, we show that the users perceive web login for increasing and decreasing RTs in different ways. So, we conduct interview among specific users applying increased and decreased RTs in particular web login to rank the users satisfaction level. Study of the two results for RTs of the web login page is presented.

The Internet, thirty-three year ago, fighting for recognition into the mainstream market, is being emerged as a single biggest application in the history of last century. Today, vast majority of people use Internet services, specifically, web which is a single most key driver of internet offering services ranging from social networking, VoIP (voice over IP), online gaming, entertainment and other professional services. Due to its rapidly emerging status from a facility to a necessity, Internet is becoming a basic utility in human day to day life. However, together with advancement in terms of bandwidth and usability of Internet services, human psychological behaviors like human patience, consciousness and expectation towards web services are also increasing proportionally. The future Internet paradigm is becoming more and more user centric. Therefore, Quality of experience, which is a process of gauging user subjective experience towards particular service, has its vital importance in future. However in current scenario a missing attribute of QoE is ‘context’ and within context there is human conscious behavior that is change from one instance to another. The aforementioned attribute often neglected by service providers and research community during web QoE (Quality of Experience) in controlled test environment. Due to the fact that Internet is everywhere e.g. at home, office and during mobility, web users activities are not always restricted to particular location and user web consciousness about performance may vary from context to context. The user centric approach in future Internet poses a real challenge to application and service providers towards provision of web services. That meets accordingly with human psychological requirements e.g. user satisfaction, consciousness, emotions etc. The empirical part of the research is to investigate the impact of user environmental and psychological context on user conscious behavior towards web performance. The purpose to quantify up to what extent this can create a significant impact on quality of experience.