Future wireless networks will be required to support multimedia traffic in addition to traditional best-effort network services. Supporting multimedia traffic on wired networks presents a large number of design problems, particularly for networks that run connectionless data transport protocols such as the TCP/IP protocol suite. These problems are magnified for wireless links, as the quality of such links varies widely and uncontrollably. This dissertation presents new tools developed for the design and realization of wireless networks including, for the first time, analytical channel models for predicting the efficacy of error control codes, interleaving schemes, and signalling protocols, and several novel algorithms for matching and adapting system parameters (such as error control and frame length) to time-varying channels and Quality of Service (QoS) requirements.

Video frame rate up-conversion is an important issue for multimedia systems in achieving better video quality and motion portrayal. Motion-compensated methods offer better quality interpolated frames since the interpolation is performed along the motion trajectory. In addition, computational complexity, regularity, and memory bandwidth are important for a real-time implementation. Motion-compensated frame rate up-conversion (MC-FRC) is composed of two main parts: motion estimation (ME) and motion-compensated frame interpolation (MCFI). Since ME is an essential part of MC-FRC, a new fast motion estimation (FME) algorithm capable of producing sub-sample motion vectors at low computational-complexity has been developed. Unlike existing FME algorithms, the developed algorithm considers the low complexity sub-sample accuracy in designing the search pattern for FME. The developed FME algorithm is designed in such a way that the block distortion measure (BDM) is modeled as a parametric surface in the vicinity of the integer-sample motion vector; this modeling enables low computational-complexity sub-sample motion estimation without pixel interpolation. MC-FRC needs more accurate motion trajectories for better video quality; hence, a novel true-motion estimation (TME) algorithm targeting to track the projected object motion has been developed for video processing applications, such as motion-compensated frame interpolation (MCFI), deinterlacing, and denoising. Developed TME algorithm considers not only the computational complexity and regularity but also memory bandwidth. TME is obtained by imposing implicit and explicit smoothness constraints on block matching algorithm (BMA). In addition, it employs a novel adaptive clustering algorithm to keep the low-complexity at reasonable levels yet enable exploiting more spatiotemporal neighbors. To produce better quality interpolated frames, dense motion field at the interpolation instants are obtained for both forward and backward motion vectors (MVs); then, bidirectional motion compensation using forward and backward MVs is applied by mixing both elegantly.

Thesis (M. Arch.)--University of Hong Kong, 2002. / Includes special study report entitled: Media art : space. Includes bibliographical references.

There is an increasing demand for multimedia services in heterogeneous wireless networks. Considering the highly dynamic wireless channels and the relatively large size of the multimedia data, how to support efficient and reliable multimedia delivery is a pressing issue. In this dissertation, we investigate the multimedia delivery algorithms in heterogeneous wireless networks from three different aspects. First, we study the single-flow rate adaptation of video streaming algorithm over multiple wireless interfaces. In order to maintain high video streaming quality while reducing the wireless service cost, the optimal video streaming process with multiple links is formulated as a Markov Decision Process (MDP). The reward function is designed to consider the quality of service (QoS) requirements for video traffic, such as the startup latency, playback fluency, average playback quality, playback smoothness and wireless service cost. To solve the MDP in real time, we propose an adaptive, best-action search algorithm to obtain a sub-optimal solution. To evaluate the performance of the proposed adaptation algorithm, we implemented a testbed using the Android mobile phone and the Scalable Video Coding (SVC) codec and conducted experiments with real video flow. Then, with the multiple multimedia flows competing for limited wireless resources, we propose a utility-based scheduling algorithm for multimedia transmission in Drive-thru Internet. A utility model is devised to map the throughput to user's satisfaction level in terms of multimedia data quality, such as Peak Signal-to-Noise Ratio (PSNR) of video. The objective of the scheduling problem is to maximize the total utility. Then the optimization problem is formulated as a finite-state decision problem with the assumption that future arrival information is known, and it is solved by a searching algorithm as the benchmark. To obtain a real-time solution, a practical heuristic algorithm based on the concept of utility potential is devised. We further implemented the solution and conducted extensive simulations using NS-3. Finally, the multimedia dissemination problem in large-scale VANETs is investigated. We first utilize a hybrid-network framework to address the mobility and scalability issues in large-scale VANETs content distribution. Then, we formulate a utility-based maximization problem to find the best delivery strategy and select an optimal path for the multimedia data dissemination, where the utility function has taken the delivery delay, the Quality of Services (QoS) and the storage cost into consideration. We obtain the closed-form of the utility function, and then obtain the optimal solution of the problem with the convex optimization theory. Finally, we conducted extensive trace-driven simulations to evaluate the performance of the proposed algorithm with real traces collected by taxis in Shanghai. In summary, the research outcomes of the dissertation can contribute to three different aspects of multimedia delivery in heterogeneous wireless networks. First, we have proposed a real-time rate adaptation algorithm for video streaming with multiple wireless interfaces, to maintain the high quality while reducing the wireless services cost. Second, we have presented an optimal scheduling algorithm which can maximize the total satisfaction for multimedia transmission in Drive-thru Internet. Third, we have derived the theoretical analysis of the utility functions including delivery delay, QoS and the storage cost, and have obtained an optimal solution for multimedia data dissemination in large-scale VANETs to achieve the highest utility. / Graduate / 0984 / 0544

Thesis (M.Arch.)--University of Hong Kong, 2002. / Includes special study report entitled : Media art : space. Includes bibliographical references. Also available in print.

Multimedia retrieval systems are supposed to provide the method and the interface for users to retrieve particular multimedia data from multimedia collections. Although, many different retrieval techniques evolved from times when the search in multimedia collections firstly appeared as a research task, not all of them can fulfill specific requirements that the multimedia exploration is determined for. The multimedia exploration is designated for revealing the content of a whole multimedia collection, quite often totally unknown to the users who retrieve data. Because of these facts a multimedia exploration system has to solve problems like, how to visualize (usually multidimensional) multimedia data, how to scale data retrieval from arbitrarily large collections and how to design such an interface that the users could intuitively use for the exploration. Taking these problems into consideration, we proposed and evaluated ideas for building the system that is well-suited for the multimedia exploration. We outlined the overall architecture of a multimedia exploration system, created the Multi-Layer Exploration Structure (MLES) as an underlying index structure that should solve problems of efficient and intuitive data retrieval and we also proposed definitions of exploration operations as an interactive and...

Le projet SoC-Trace a pour objectif le développement d'un ensemble de méthodes et d'outils basés sur les traces d'éxécution d'applications embarquées multicoeur afin de répondre aux besoins croissants d'observabilité et de 'débogabilité' requis par l'industrie. Le projet vise en particulier le développement de nouvelles méthodes d'analyse, s'appuyant sur différentes techniques d'analyse de données telles que l'analyse probabiliste, la fouille de données, et l'agrégation de données. Elles devraient permettre l'identification automatique d'anomalies,l'analyse des corrélations et dépendances complexes entre plusieurs composants d'une application embarquées ainsi que la maîtrise du volume important des traces qui peut désormais dépasser le GigaOctet. L'objectif de la thèse est de fournir une représentation de haut niveau des informations contenues dans les traces, basée sur la sémantique. Il s'agira dans un premier temps de développer un outil efficace de comparaison entre traces;de définir une distance démantique adaptée aux traces, puis dans un second temps d'analyser et d'interpréter les résultats des comparaisons de traces en se basant sur la distance définie. / The SoC-Trace project aims to develop a set of methods and tools based on execution traces of multicore embedded applications to meet the growing needs of observability and 'débogability' required by the industry. The project aims in particular the development of new analytical methods, based on different data analysis techniques such as probabilistic analysis, data mining, and data aggregation. They should allow the automatic identification of anomalies, the analysis of complex correlations and dependencies between different components of an embedded application and control of the volume traces that can now exceed the gigabyte. The aim of the thesis is to provide a high-level representation of information in the trace based semantics. It will initially develop an effective tool for comparing traces, to define a semantic distance for execution traces, then a second time to analyze and interpret the results of comparisons of traces based on the defined distance.

xi, 284 p. A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number. / My dissertation delves into the recent articulation of popular nationalism in Mainland China, with particular emphasis on the changes that globalization and transnationalism have brought about to the representation of the Chinese nation in sentimental terms. Complementing the rich existing literature of Chinese nationalism that focuses mainly on the pre-1949 period, my study explores the less-treaded contemporary era characterized by the new historical condition of postsocialism, which features a residual of the socialist past as well as its reinvention under new overwhelming trends of globalization. Postsocialism and its consequences-the deepening of a neoliberalist economic refonn, the state-intellectual promotion of cultural economy, the emergence of a dominant consumer culture, etc.-have produced new issues existing scholarship on Chinese nationalism has yet to address. One such issue is how the paradoxical entity of the "nation" in time and space has been fragmented by the accretion of diversified voices from a wide spectrum of Chinese society. In postsocialist China, the agents imagining the nation include not only regulars like the state and intellectuals, but also new players like mass-media elites and netizens (wangmin). I argue that these voices of different social forces that break up the hegemony of the state in representing the nation-the result of which being not that the state is excluded from this enterprise but that it now tells only part of the story-become expressed as modes of national sentiments (minzu qinggan) when the nation is imagined under the historical condition of postsocialism. My study then explores in detail the fashioning and refashioning of contemporary Chinese subjectivity, as it relates through the joining of national sentiments to the literal and figurative body of the nation and the social power structure, by analyzing these specific voices in a broad range of popular texts from TV, film, and the Internet. The detailed examination includes four chapters dealing with specific modes of national sentiments articulated by the intellectuals, the state, the mass-media elites, and the netizens, respectively. / Committee in charge: Tze-lan Sang, Co-Chairperson, East Asian Languages & Literature; David Leiwei Li, Co-Chairperson, English; Maram Epstein, Member, East Asian Languages & Literature; Bryna Goodman, Outside Member, History

O contexto tecnológico percebido em vários setores da sociedade brasileira impulsiona a sua utilização em sala de aula que, por sua vez, não deve estar desconectada dessa realidade. Neste cenário, os materiais digitais no formato de multimídia interativa são reconhecidos como uma possibilidade educativa. Importantes avaliações reconhecem as dificuldades nas habilidades de leitura e escrita de alunos do Ensino Fundamental, como a Prova Brasil e o Indicador de Analfabetismo Funcional (INAF). O referencial teórico desta tese está ancorado na Teoria Cognitiva de Aprendizagem Multimídia, do inglês Cognitive Theory Multimedia Learning (CTML), principalmente nos princípios de interatividade e multimídia propostos por Richard Mayer, publicados em 2001 e 2011 e que constituem relevante orientação para projetos de Objetos de Aprendizagem Multimídia Interativos (OAMI) eficazes. Além disso, esta tese adota as taxonomias de Schwier e Misanchuk de 1993 e de Sims de 1997 e 2000, sobre interatividade em educação. Trata-se de uma pesquisa qualitativa e quantitativa, cujo objetivo é comprovar se e como os diferentes modelos de Objetos de Aprendizagem Multimídia Interativos possibilitam o aprimoramento da capacidade de leitura e escrita dos alunos nos anos iniciais do Ensino Fundamental. Os experimentos foram realizados com alunos do quinto ano do Ensino Fundamental de uma escola pública da periferia de Santa Maria - RS, durante as aulas em sala de Informática entre 2011 e 2013. Para testar as hipóteses deste estudo, foram realizadas diferentes etapas que incluem: estudo exploratório, estudo piloto, segundo estudo e o questionário sobre os objetos de aprendizagem multimídia, o qual foi aplicado em 2011 e 2013. Os dados levantados no estudo piloto de 2011 serviram como base para a proposição do segundo estudo em 2013 que definiu diferentes condições experimentais, com os tipos e níveis de interatividade, as mídias a serem utilizadas e as habilidades referentes ao conteúdo abordado nas multimídias. Inicialmente testou-se a normalidade dos dados, empregando-se o teste de Kolmogorov-Smirnov e constatou-se que os dados não seguiam uma distribuição normal (p < 0,05). A partir desse resultado, optou-se pela realização de testes não paramétricos para a comparação entre os valores dos acertos e dos erros, das Multimídias do Grupo Teste e do Grupo Controle. As respostas dos questionários (2011 e 2013) foram analisadas (Teste Qui-quadrado). As análises estatísticas conjuntas indicam algumas versões de multimídia com resultados significativos e, através dos questionários, foi possível detectar algumas variáveis que provavelmente influenciaram positivamente no desempenho dos alunos, chegando-se à conclusão de que os modelos de Objetos de Aprendizagem Multimídia Interativos utilizados nos experimentos e a sequência / The technological context perceived in various sectors of Brazilian society drives its use in the classroom, which in turn should not be disconnected from this reality. In this scenario, the digital materials in an interactive multimedia format are recognized as an educational opportunity. Important assessments as Prova Brasil (Brazil Test) and the Functional Illiteracy Indicator (INAF - Indicador de Analfabetismo Funcional), acknowledge the reading and writing skills difficulties of elementary school students. The theoretical framework of this thesis is anchored in the Cognitive Theory of Multimedia Learning (CTML), mainly on the interactivity and multimedia principles proposed by Richard Mayer, published in 2001 and 2011 and which are relevant guidance to effective projects of Interactive Multimedia Learning Objects. Moreover, this thesis adopts the interactivity education taxonomies proposed by Schwier and Misanchuk 1993 and Sims 1997 and 2000. This is a qualitative and quantitative research, whose goal is to prove whether and how the different models of Interactive Multimedia Learning Objects enable the improvement of reading and writing ability of students in the early years of elementary school. The experiments were conducted with students of the fifth grade of elementary school in a public school at the outskirts of Santa Maria – RS, during classes in Computer room between 2011 and 2013. In order to test the hypotheses of this study, different steps were performed including the following: exploratory study, pilot study, a second study and the multimedia learning objects questionnaire, which was applied in 2011 and 2013. The data collected during the 2011 pilot study, were the basis for the proposition of the second study performed in 2013 which defined the different experimental conditions with the types and levels of interactivity, media to be used and the skills related to the content addressed in multimedia. Initially, data normality was tested using the Kolmogorov - Smirnov test and it was confirmed data did not follow a normal distribution (p<0.05). From this result, it was decided to perform non-parametric tests to compare the values of the successes and the mistakes between the Multimedia Test Group and Control Group. The surveys (2011 and 2013) answers were analyzed (chi–square test). Join statistical analyses indicate some versions of multimedia with significant results and through the questionnaires; it was possible to detect some variables that probably influenced positively on students’ performance. This supports the conclusion that the models of Interactive Multimedia Learning Objects and the didactic sequence used in the experiments enabled the researched people to improve their ability to read and write.

Made available in DSpace on 2016-06-02T19:03:59Z (GMT). No. of bitstreams: 1 6547.pdf: 18207568 bytes, checksum: 3178104b1f9800bdbe79b401c9aeaf51 (MD5) Previous issue date: 2014-10-15 / Financiadora de Estudos e Projetos / Interactive multimedia applications can turn contents into a much more interesting presentation for users, promote more effective transmission of information, hold the user s attention and eventually promote more satisfaction. However, it is observed that the spread of such applications is very timid. Multimedia content, in general, has been summarized to video and hypermedia documents based on images and text. There are few effective initiatives interactivity with content that benefit from media synchronization. The environment of the Interactive Digital TV offers good potential for exploitation of sync media, however we observe numerous obstacles arising from the conservatism of the industry. The few options available to viewers often end up being ignored. Some reasons may explain the low adoption of interactive multimedia applications: (i) the production of such content is complex - existing authoring tools contribute little to simplify this process, keeping away unskilled designers and developers who choose to use content that can be captured in a simple way (usually video); (ii) the presentation of interactive multimedia content may require specific environments or applications not very widespread or require specialized development; (iii) the content consumption should occur on multiple platforms, making it expensive to develop specific applications for each; (iv) there is a lack of applications widely known to the general public that are really attractive and innovative and that stimulate interactivity. It is believed that this scenario can be changed and interactive multimedia applications can contribute to user satisfaction. It has been hypothesized that attractive interactive multimedia applications can be built with automatic or semiautomatic incorporation, to a leading media, of other media related to it. Related media may be the result of human authorship, with facilitators support, capturing context information, mining the collective interaction in presentation sessions with multiple viewers or combinations of these sources. Based on several published articles, authored or co-authored by the author of this thesis and related to projects managed by him, this text presents efforts and results that contribute to the validation of the hypothesis. These are works that address aspects of multimedia authoring, dissemination of multimedia applications on multiple platforms and media synchronization, all inherent to innovative applications with strong potential to captivate users and serve as catalysts for new applications. / Aplicações multimídia interativas podem tornar conteúdos muito mais interessantes para os usuários, promover transmissão de informação mais efetiva, prender a atenção do usuário e eventualmente promover maior satisfação. Entretanto, observa-se que a disseminação desse tipo de aplicação é muito tímida. Conteúdo multimídia, de maneira geral, tem se resumido a vídeo e documentos hipermídia baseados em imagem e texto. São poucas as iniciativas de interatividade efetiva com o conteúdo que se beneficiam da sincronização de mídias. O ambiente da TV Digital Interativa apresenta bom potencial para exploração do sincronismo de mídia, entretanto observam-se inúmeros obstáculos decorrentes do conservadorismo do setor. As poucas opções disponíveis aos telespectadores acabam sendo muitas vezes ignoradas. Algumas razões podem explicar a baixa adoção de aplicações multimídia interativas:( i) a produção desse tipo de conteúdo é complexa - as ferramentas de autoria pouco contribuem para simplificar esse processo, em geral afastando designers e desenvolvedores não especializados, que optam por utilizar conteúdos capturados de maneira simples (geralmente vídeo); (ii) a apresentação de conteúdo multimídia interativo pode requerer ambientes ou aplicações específicas não muito disseminadas ou que necessitam desenvolvimento especializado; (iii) é desejável que o consumo de conteúdo ocorra em múltiplas plataformas, tornando custoso o desenvolvimento específico para cada uma; (iv) não se conhecem aplicações que sejam inovadoras e que realmente estimulam a interatividade. Acredita-se que esse cenário pode ser mudado e que aplicações multimídia interativas possam contribuir com a satisfação do usuário. Tem-se como hipótese que aplicações multimídia interativas e potencialmente atrativas podem ser construídas com a incorporação automática ou semiautomática, a uma mídia principal, de outras mídias a ela relacionadas. As mídias relacionadas podem ser resultado de autoria humana, com apoios facilitadores, da captura de informações de contexto, de mineração da interação coletiva em sessões de apresentação com multiespectadores ou combinações dessas fontes. Fundamentando-se em artigos publicados, com autoria ou coautoria do autor desta tese e relacionados a projetos por ele gerenciados, apresenta-se neste texto os esforços realizados e os resultados que contribuem para a validação da hipótese. São trabalhos que abordam aspectos de autoria multimídia, da difusão de aplicações multimídia em múltiplas plataformas e da sincronização de mídias, todos inerentes a aplicações inovadoras com potencial de cativar usuários e servirem como catalisadores de novas aplicações.