The objective of the proposed research is to design and evaluate end-to-end solutions to support the Quality of Experience (QoE) for the Internet Protocol Television (IPTV) service. IPTV is a system that integrates voice, video, and data delivery into a single Internet Protocol (IP) framework to enable interactive broadcasting services at the subscribers. It promises significant advantages for both service providers and subscribers. For instance, unlike conventional broadcasting systems, IPTV broadcasts will not be restricted by the limited number of channels in the broadcast/radio spectrum. Furthermore, IPTV will provide its subscribers with the opportunity to access and interact with a wide variety of high-quality on-demand video content over the Internet. However, these advantages come at the expense of stricter quality of service (QoS) requirements than traditional Internet applications. Since IPTV is considered as a real-time broadcast service over the Internet, the success of the IPTV service depends on the QoE perceived by the end-users. The characteristics of the video traffic as well as the high-quality requirements of the IPTV broadcast impose strict requirements on transmission delay. IPTV framework has to provide mechanisms to satisfy the stringent delay, jitter, and packet loss requirements of the IPTV service over lossy transmission channels with varying characteristics. The proposed research focuses on error recovery and channel change latency problems in IPTV networks. Our specific aim is to develop a content delivery framework that integrates content features, IPTV application requirements, and network characteristics in such a way that the network resource utilization can be optimized for the given constraints on the user perceived service quality. To achieve the desired QoE levels, the proposed research focuses on the design of resource optimal server-based and peer-assisted delivery techniques. First, by analyzing the tradeoffs on the use of proactive and reactive repair techniques, a solution that optimizes the error recovery overhead is proposed. Further analysis on the proposed solution is performed by also focusing on the use of multicast error recovery techniques. By investigating the tradeoffs on the use of network-assisted and client-based channel change solutions, distributed content delivery frameworks are proposed to optimize the error recovery performance. Next, bandwidth and latency tradeoffs associated with the use of concurrent delivery streams to support the IPTV channel change are analyzed, and the results are used to develop a resource-optimal channel change framework that greatly improves the latency performance in the network. For both problems studied in this research, scalability concerns for the IPTV service are addressed by properly integrating peer-based delivery techniques into server-based solutions.

In this thesis I survey the terrain of digital interactions between youth, corporations and pop culture texts in order to complicate current visions of participatory culture. I argue that popular images of the empowered young users of a new digital democracy need to be complicated by asking questions about the politics of digital participation: about whose voices are heard, about where attention is centred, about how interactivity is defined, about who is rewarded for creative labour. The opening chapter introduces key issues within a critical examination of digital participation, including commodification, user agency and intellectual property. It also outlines my methodologies and my choice of research site – namely internet television, and the proliferation of corporate and youth practices around digitized television texts. The next two chapters provide case studies that identify and evaluate not only the interactions between corporate producers and young users, but also the power relations between the two. First, I analyze young women‘s video remixes of the program Gossip Girl. I consider the remixes as gendered texts that contribute new aesthetics and concerns, even as they reproduce dominant interpretations of contemporary girlhood. I also consider the distribution of the videos on YouTube, noting how their circulation simultaneously challenges corporate ownership and creates profit and promotion for those same corporate owners. Next, I examine interactions around the The Colbert Report. Focusing on the program‘s official discussion boards, I demonstrate how young fans have taken up Stephen Colbert‘s invitation to join in the parody by creating a vibrant, dialogic and rowdy community that has frequently come into conflict with Comedy Central producers. In their attempts to address these conflicts and create alternative spaces of their own, these young people gesture towards larger tensions over the control of public digital dialogue. The final chapter draws on my research and experience as a teacher to consider how these case studies might help us to frame our own educational projects. I call for a digital literacy curriculum that provides both a place for students to reflect on their daily activities within mediated environments and the opportunity to experiment with digital production.

In this thesis I survey the terrain of digital interactions between youth, corporations and pop culture texts in order to complicate current visions of participatory culture. I argue that popular images of the empowered young users of a new digital democracy need to be complicated by asking questions about the politics of digital participation: about whose voices are heard, about where attention is centred, about how interactivity is defined, about who is rewarded for creative labour. The opening chapter introduces key issues within a critical examination of digital participation, including commodification, user agency and intellectual property. It also outlines my methodologies and my choice of research site – namely internet television, and the proliferation of corporate and youth practices around digitized television texts. The next two chapters provide case studies that identify and evaluate not only the interactions between corporate producers and young users, but also the power relations between the two. First, I analyze young women‘s video remixes of the program Gossip Girl. I consider the remixes as gendered texts that contribute new aesthetics and concerns, even as they reproduce dominant interpretations of contemporary girlhood. I also consider the distribution of the videos on YouTube, noting how their circulation simultaneously challenges corporate ownership and creates profit and promotion for those same corporate owners. Next, I examine interactions around the The Colbert Report. Focusing on the program‘s official discussion boards, I demonstrate how young fans have taken up Stephen Colbert‘s invitation to join in the parody by creating a vibrant, dialogic and rowdy community that has frequently come into conflict with Comedy Central producers. In their attempts to address these conflicts and create alternative spaces of their own, these young people gesture towards larger tensions over the control of public digital dialogue. The final chapter draws on my research and experience as a teacher to consider how these case studies might help us to frame our own educational projects. I call for a digital literacy curriculum that provides both a place for students to reflect on their daily activities within mediated environments and the opportunity to experiment with digital production.

O presente trabalho propõe uma arquitetura de controle de admissão de conexão para servidores de vídeo sob demanda, que visa introduzir garantias determinísticas para o atraso e aumentar a taxa de utilização do enlace. O sistema tira proveito do fato de que os arquivos de vídeo podem ser pré-processados, para calcular os parâmetros de tempo e espaço, com o objetivo de estimar a banda efetiva de um agregado de streams sobre o regime assintótico de muitas fontes. A geração automática dos arquivos de trace permite a caracterização total do processo de chegada dos dados, aumentando a precisão do cálculo da taxa de serviço requerida. Para contornar o problema de predição de tráfego, uma vez que o sistema não captura o comportamento dos fluxos de vídeo no domínio do tempo, o enlace é divido em vários enlaces virtuais, que transportam somente fluxos de vídeos idênticos. A utilização de um mecanismo, que compartilha a banda excedente, diminui o desperdício de recursos e a probabilidade de ocorrer uma violação aos parâmetros de QoS impostos. Todo processo de admissão de conexão é auxiliado por um sistema gestor de base de dados, onde uma função decide se deve ou não aceitar uma conexão pela simples comparação das somas das bandas efetivas das conexões com os recursos disponíveis. A eficiência do modelo proposto é analisada e comparada aos modelos determinísticos tradicionais. / This work proposes a admission control architecture for video-on-demand servers, which provide deterministic guarantees on the maximum delay of video traffic and increase the network resource utilization. The framework take advantage of the fact that stored video streams can be processed off-line to calculate the space and time parameters in order to estimate its effective bandwidth under the many sources asymptotic regime. The automatic generation of video data representation (packetized and encapsulated in network protocols) in textual format allows a full characterization of the underlying process so as to precisely calculate its bandwidth requirements. To bypass the traffic prediction problem, since the off-line estimation does not capture the exact dynamics of the video stream in the time domain, the link is divided into several virtual links, where only streams with same content are multiplexed (group multiplexing approach). The introduction of a borrowing mechanism to distribute the excess bandwidth to other groups which request service increases the resource utilization and QoS. The admission control is aided by a Database Management System, where a stored procedure decides whether to accept or reject a connection by simple compare the sum of effective bandwidths for the traffic streams with the available resources. The efficiency of the model is analyzed and compared with deterministic approachs.

The diploma thesis is devoted to freshly emerging TV shows about architecture and public space on the platforms of the two biggest internet TVs in the Czech Republic: Stream.cz and MALL.TV. The work specifically analyzes the following broadcasts: Gebrian VS, Gebrian: Surprising Buildings, Gebrian: PLUS/MINUS, in terms of their distinctive formats. The main purpose of the thesis is to point out the existence of these programs and to identify the formal and genre aspects that shape their unique form. The important part of the research is carried out by comparing the shows based on the platforms on which they are created and which provide different conditions for production. The following theoretical foundations were used: genre theory, presentation of specific genres related to the examined programs, media convergence and internet TVs and their recent production. The qualitative elements, including the visual communication means, which lead to the recognition of the genre construction of a specific TV show, are examined by combined visual and semiotic analysis. Quantitative elements such as tone and footage are analyzed by content analysis. The research reveals some significant differences in the examined TV shows based on a platform they are made on. These are identified as different approaches to...

La perte de conjoints et d’amis, la réduction progressive de leur mobilité et l’éloignement de plus en plus fréquent des enfants, plongent souvent les personnes âgées dans un isolement qui peut générer des dépressions qui ont à leur tour un impact négatif sur la santé. Des études médicales ont même démontré que l’isolement social augmente le risque de mortalité des personnes âgées. Alors que de nombreux programmes de recherche s’intéressent à développer une variété de solutions technologiques liées à la fragilité physique et/ou cognitive des personnes âgées pour qu’ils puissent rester le plus longtemps possible à domicile, nous nous intéressons à leur fragilité sociale qui limite leurs capacités à rester en contact avec la société. Nous émettons l’hypothèse que les technologies de l’information ont un rôle important à jouer pour apporter une solution à l’isolement social des personnes âgées. Mais concevoir des services adaptés et s’assurer de leur appropriation restent des questions ouvertes, auxquelles nous tentons de proposer des réponses, à la fois au niveau méthodologique et instrumental. Nous présentons une démarche de conception de services pour les personnes âgées, qui s’appuie sur la participation des futurs utilisateurs dans le cadre d’un «Living Lab». Nous illustrons cette démarche grâce à notre participation à un projet européen dont l’objectif est de développer des applications de télévision sociale pour contribuer au développement des interactions sociales entre pairs / Encouraging seniors to stay at home as long as possible is associated with a higher risk of social isolation. Extensive researches have established the strong relationship between social isolation and health, considering social engagement as an important component influencing psychological well-being and self-esteem of elderly people. In other words, aging well at home cannot be reduced to the management of physical and cognitive frailties and technologies should also tackle the quality of life of the elderly by fostering their social interactions especially for those who are living alone. We postulate that ICTs could alleviate elderly loneliness, in order to cope with their social frailty. However, designing appropriate services and ensure their adoption by the elderly remain open questions, which we try to provide answers at both methodological and instrumental level. We propose an approach to design services for the elderly based on the participation of the future users as part of a "Living Lab". We illustrate this approach by our participation in a European project aiming at developing and evaluating Social TV services. The objective is to foster social interactions among peers to enhance or restore social ties, with the goal of increasing psychological well-being and self-esteem of the elderly living alone

The topic of this thesis is the online TV channel Stream. In the theoretical part, we described how online TV works in general. The following paragraph depicted the milestones of Stream TV. The practical part was dedicated to the semiotic analysis of Luděk Staněk's TV show of the online TV channel Stream. This chapter also includes the interview with the program presenter Luděk Staněk. In the interview, we dealt with Staněk's role in the show. The intention of this thesis was to describe how the online TV channel Stream works and analyze the Luděk Staněk's show.