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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Sistema de monitoramento de transmissão de TV digital em redes convergentes heterogêneas. / Digital TV transmission monitoring system for heterogeneous converging networks.

Ian Korolkovas 15 August 2007 (has links)
A grande evolução nos sistemas de comunicação, relacionados à transmissão de conteúdo multimídia nas redes de comunicação de dados e de transmissão de TV, demanda soluções de gerência da qualidade de serviço fim-a-fim. Diante deste cenário é proposta nesse trabalho a definição, implementação e validação de uma solução para monitoramento de transmissão de mídia que permite ser aplicada em arquiteturas de redes heterogêneas. Essas redes possuem a característica de integrar diversas tecnologias de redes de comunicação de dados e de telecomunicações, envolvendo redes modernas e antigas, padronizadas e proprietárias. Este trabalho apresenta um sistema de monitoramento para transmissão de TV Digital em ambientes heterogêneos convergentes, isto é, redes que utilizam tecnologias e meios de transmissão distintos para transmissão de vários tipos de fluxos, e com foco na aplicação TV Digital. Para isso, são discutidos aspectos fundamentais para o monitoramento de fluxo de TV Digital neste tipo de rede e é feita uma análise da comunicação entre os subsistemas do ambiente. O sistema de monitoramento possui uma arquitetura definida que se baseia no protocolo RTP Real-time Transport Protocol, para suportar a transmissão de mídias, como áudio e vídeo, em redes heterogêneas. A fim de validar esta arquitetura foi implementado um protótipo, como prova de conceito, que obtém dados através da base de informações de gerência (MIB) RTP. Os resultados gerados pelo protótipo consolidam informações relativas à variação de atraso em uma interface web de gerenciamento através de monitores distribuídos pela rede. / The great evolution in the telecommunication systems related to the transmission of multimidia contents in the data communication networks and TV transmission, demands management solutions in which regards quality of end-to-end services. Taking this scenario into consideration, it is proposed in this work the definition and implementation of a solution to monitor media transmition that can be applied to heterogeneous network architectures. The feature of such networks is to integrate different data communication network technologies and telecommunication, involving legacy and modern networks, standarized and proprietary. This work presents a monitoring system for digital TV transmission in heterogeneous converging environments, that is, networks that use different technologies and transmission means for the Digital TV application. Therefore, key aspects for monitoring the digital TV flow in this kind of network are pointed out, as well as an analysis of the communication among the environment subsystems. The monitoring system has a defined architecture, based on the RTP Real-time Transport Protocol, to support the media transmission, such as audio and video, in heterogeneous networks. In order to validate this architecture, a prototype was implemented, as concept evidence, that obtains data from the management information base (MIB) RTP. The results generated by the prototype consolidate information related to the delay variation (jitter) in a management web interface through monitors distributed around the network.
42

Uma interface de comunicação sem fio em TV digital baseada em rádio definido por programa de computador. / A wireless communication interface based on software defined radio in digital TV.

Rodrigo Admir Vaz 19 July 2007 (has links)
O surgimento das modernas tecnologias de comunicação e informação multimídia vem impactando e transformando a vida da sociedade atual, alterando hábitos e costumes de seus usuários. A visualização destes efeitos não tem sido diferente no universo da TV Digital. A sua inovadora proposta de interatividade entre usuário e emissora, promete revolucionar hábitos e costumes dos telespectadores. A implementação do Canal de Interatividade da TV Digital através da Internet é uma proposta particular do sistema brasileiro de TV Digital e pretende melhorar a qualidade de vida da população provendo interatividade no sistema, além de conduzir à melhoria da qualidade da programação oferecida aos seus telespectadores. Outro tipo de tecnologia de comunicação que atualmente vem ganhando cada vez mais espaço no cotidiano é a tecnologia de comunicação sem fio, especialmente aquelas que oferecem altas taxas de transferência de dados e aquelas que oferecem grande mobilidade, tornando as comunicações cada vez mais personalizadas e pessoais. Como grande inovação, este trabalho propõe a implementação do Canal de Interatividade da TV Digital através da Internet, utilizando redes de comunicação sem fio, com mais de uma tecnologia de comunicação sem fio presente no mesmo Terminal de Acesso à TV digital, tirando proveito da inovativa metodologia de reconfiguração de Rádio Definido por Programa de Computador. Desta forma, permiti-se que, quando uma determinada rede de comunicação sem fio estiver indisponível em dado momento e/ou região, o sistema se reorganize e utilize outra rede de comunicação sem fio que esteja à disposição. / The sprouting of the modern communication technologies and multimedia information comes impacting and transforming the life of the current society, modifying habits and customs of its users. The visualization of these effects has not been different in the universe of the Digital TV. Its innovative proposal of interactivity between the user and the broadcaster, promises to revolutionize habits and customs of the viewers. The implementation of the Interactivity Channel of the Digital TV through the Internet is a particular proposal of the Brazilian DTV system and intends to improve the quality of life of the population providing interactivity of the system, beyond leading to the improvement of the quality of the offered programming to its viewers. Another type of communication technology that currently comes ga ining each time more space in the daily life is the wireless technology, especially those which offer high data rates and those which offer great mobility, becoming each time more personalized and personal. As great innovation, this dissertation considers the implementation of the Interactivity Channel of the Digital TV through the Internet, using wireless communication, with more than one wireless technology in the same Set-Top-Box, taking off advantage of the innovative Software Defined Radio reconfiguration methodology. In such a way, it is allowed when one determined wireless network will be unavailable at any given time and/or region, the system if reorganizes itself and uses another available wireless network.
43

Codificação escalável de vídeo para recepção fixa no sistema brasileiro de televisão digital. / Scalable video coding for fixed reception in the Brazilian digital TV system.

Rogério Pernas Nunes 29 May 2009 (has links)
Em dezembro de 2007, a partir da cidade de São Paulo, as transmissões de televisão digital terrestre e aberta tiveram início no Brasil. Um avanço significativo do Sistema Brasileiro de TV Digital (SBTVD) foi a adoção do padrão H.264/AVC e o formato de vídeo 1080i para a codificação de vídeo em alta definição. A adoção em larga escala de tecnologia de alta definição tem sido um processo observado em vários mercados do mundo, e novos formatos superiores ao 1080i já estão sendo discutidos e propostos. Tendo em vista o que será a próxima geração da televisão, centros de pesquisa, como o centro japonês da emissora NHK, investigam os fatores humanos determinantes para caracterizar o sistema que deverá ser o último passo em tecnologia de televisão 2D. Já nomeado de UHDTV, este sistema deve contemplar resolução de 7680 pontos horizontais por 4320 pontos verticais, além de outras características ainda em estudo. Ao mesmo tempo, o trabalho aqui apresentado discute as ferramentas de suporte da escalabilidade na codificação multimídia como forma de evolução gradual dos formatos de vídeo na radiodifusão. Especificamente este trabalho sistematiza as ferramentas de escalabilidade do padrão H.264/AVC tendo em vista a sua aplicação ao SBTVD. Neste sentido, são discutidas as possibilidades de evolução do sistema frente à escalabilidade e são apresentados levantamentos experimentais da atual ocupação do espectro na cidade de São Paulo, evidenciando a disponibilidade de taxa para expansões. São apresentados também resultados iniciais relativos à codificação SVC, que apontam objetivamente as vantagens da escalabilidade sobre o simulcast, evidenciando que esta técnica pode ser utilizada no SBTVD para prover novos formatos de vídeo, tendo como premissa a compatibilidade com os atuais receptores que suportam o formato 1080i. O trabalho apresenta contribuições teóricas e experimentais na direção de adoção da escalabilidade no SBTVD, apontando também possíveis trabalhos futuros que, se realizados, poderão confirmar a transmissão de formatos superiores de vídeo nos próximos anos no SBTVD. / On December 2007, starting from São Paulo city, the open digital terrestrial transmissions were launched in Brazil. A significant improvement of the Brazilian Digital TV System (SBTVD) was the adoption of the H.264/AVC standard supporting the 1080i video format for the high definition video coding. Wide adoption of high definition technology has been a process that can be observed in lots of countries, and new video formats, beyond 1080i have already been discussed and proposed. With both eyes in the next generation of TV, research centers like Japanese broadcaster NHK investigate human factors that should drive the system specifications of this one that may be the last step in terms of 2D television technology. Named UHDTV, the system may support 7680 horizontal dots per 4320 vertical dots in terms of resolution among other features. At the same time, the work exposed here discusses tools that support multimedia coding scalability as a way of gradually improving video formats for broadcast. This work specially deals with the H.264/AVC standard scalability tools, aiming their use within SBTVD. Therefore, the evolution of the system is discussed based on scalability and experimental results related to the digital TV spectral occupation in São Paulo city are analyzed, showing that there is enough exceeding bit rate available for future expansion. Initial results related to SVC coding are also shown, objectively indicating that video scalability is more advantageous than simulcast and that this technique can be used in SBTVD to provide new video formats, keeping compatibility with current receivers that only support 1080i format. This work presents theoretical and experimental contributions towards the adoption of SVC in the SBTVD, pointing out some future works that, if executed, could confirm the transmission of new video format in SBTVD in the next years.
44

Re-ver TV: um estudo sobre os processos e estratégias de deigitalização da televisão no Brasil / Re-ver TV: um estudo sobre os processos e estratégias de deigitalização da televisão no Brasil

Francisco, Rodrigo Eduardo Botelho 14 August 2009 (has links)
Este trabalho tem como objetivo, no contexto da implantação da TV Digital no Brasil, promover uma reflexão sobre o conceito de interatividade na sociedade contemporânea e, considerando as possibilidades dos novos suportes tecnológicos, contribuir para o desenvolvimento de novos formatos e conteúdos de produtos audiovisuais que, de fato, contribuam para a democratização da comunicação. Para tanto, realiza uma revisão bibliográfica que busca não só um embasamento teórico, mas também referendar a argumentação de que o conceito de interatividade sofre um processo de banalização e necessita ser depurado. A partir disso é apresentado um quadro sobre o conceito que ressalta a existência de uma diversidade de terminologias e definições. O projeto, em particular, faz a opção pelas caracterizações como reativa e mútua para interação mediada por computador e as usa num estudo de caso de programas interativos para televisão digital brasileira. Além disso, descreve vários outros aspectos técnicos que envolvem a estruturação de documentos hipermídia com o intuito de enveredar pelos caminhos da informática e suas concepções, já que isso passa a interferir sobremaneira nos processos produtivos audiovisuais. O resultado dessa trajetória não é conclusivo, assim como não parecem ser quaisquer estudos relacionados aos impactos do paradigma digital sobre os meios de comunicação, mas, de certo, explora as intersecções existentes entre TV e Interatividade, questões-chave que refletem as inquietações desta dissertação. / This work aims to, in the context of the implementation of the digital TV in Brazil, promote reflexion on the concept of interactivity in current society, and, by considering the possibilities created by new technological supports, to contribute to the development of new formats and contents of hypermedia documents that truly contribute to the democratization of communication. In order to do that it carries out bibligraphic review which pursues not only theoretical support but also validation of the argument that the concept of interactivity goes through a process of banalization and needs depurating. Upon this is built a picture of the concept that stresses an existing diversity of terminology and definitions. The project itself opts for the characterizations of computer mediated interaction as reactive and mutual and use them in a case study of interactive programs for Brazilian digital television In addition to this it describes many other technical aspects involving the structuring of hypermedia documents, aiming to move through the paths of informatics and its concepts since this interferes meaningfully in the audiovisual productive processes. This journey leads to no-conclusive results, just as other studies related to the impacts of digital paradigm to the means of communication do not either, but it certainly explores the intersections that exist between TV and interactivity key questions that reflect the questioning of this dissertation.
45

Digital videoväxel / Digital video switch

Länger, Henrik, Eriksson, Olle January 2004 (has links)
<p>This thesis discusses the possibilities to distribute digital video in a military vehicle. Today, an analogue system is used, which has a maximum capacity of eighteen video sources and the same number of monitors. The purpose of this thesis is to increase the systems capabilities regarding secure distribution and additional functions. </p><p>Both software and hardware tests are made to investigate the features of the digital video standard MPEG-2. Both the coding delay and the image quality are of great interest. Another digital video standard, DV, is considered as an alternative to MPEG-2. </p><p>Apart from different coding techniques, this work describes some distribution techniques like TCP/IP, DVB-C and USB.</p>
46

Augmenting the Remote Control : Studies in Complex Information Navigation for Digital TV

Berglund, Aseel January 2004 (has links)
The transition to digital TV is changing the television set into an entertainment as well as information supplier device that provides two-way communication with the viewer. However, the present remote control device is not appropriate for navigation through the huge amount of services and information provided by the future digital TV, presumably also a device for accessing the Internet. One possibility for coping with the complex information navigation required by TV viewers is an augmentation of the interaction tools currently available for TV. Two approaches to such an augmentation are investigated in this thesis: linking paper-based TV guides to the digital TV and enhancing the remote control unit with speech interaction. Augmentation of paper-based TV guides is a futuristic research approach based on the integration of paper-based TV guides into computation technology. This solution provides interactive paper-based TV guides that also function as a remote control for the TV. A prototype system is developed and explorative studies are conducted to investigate this approach. These studies indicate the benefits of integrating paper-based TV guides into the TV set. They also illuminate the potential to provide innovative solutions for home information systems. Integrating familiar physical artefacts, such as paper and pen into TV technology may provide easy access to information services usually provided by PCs and the Internet. Thus, the same augmentation needed for TV as an entertainment device also opens up new communication channels for providing society information to citizens who do not feel comfortable with conventional computers. The thesis also reports on studies of speech interfaces for TV information navigation. Traditional speech interfaces have several common problems, such as user acceptance and misinterpretation of user input. These problems are investigated in empirical and explorative studies with implementation of mockups and running research systems. We have found that the pragmatic solution of augmenting remote control devices by speech is a suitable solution that eases information navigation and search. / On the day of the public defence the status of articles III and V was: Submitted.
47

Digital-TV : Hur digital-TV-distributörer bygger relationer med kunder

Siwertz, Clara, Tägt, Stefan January 2006 (has links)
1997 kom riksdagen med ett förslag om att genomföra ett teknikskifte inom Sveriges marksända TV-distribution. Teknikskiftet skulle innebära att de analoga TV-sändningarna via marknätet skulle ersättas med digitala TV-sändningar och övergången skulle därför bidra med en mängd ekonomiska och tekniska fördelar. Digital-TV-sändningar erbjöds sedan tidigare av ett fåtal TV-distributörer men skulle nu bli något som fler TV-konsumenter skulle få tillgång till. Digital-TV-övergången är nu i full gång och påverkar såväl konsumenter som distributörer av digital-TV produkter och tjänster. Syftet med uppsatsen är att undersöka hur två digital-TV-distributörer anpassar sin marknadsföring för att stärka relationer till befintliga kunder och skapa relationer till nya kunder. Uppsatsen fokuserar på huruvida distributörerna tillämpar transaktionsmarknadsföring eller relationsmarknadsföring och hur den rådande digital-TV-övergången påverkar marknadsföringen. Teorier bakom relationsmarknadsföring fokuserar bland annat på relationen mellan leverantör och kund och detta är det centrala temat i uppsatsen. Värdeskapande, involvering, anpassningsförmåga, informationshantering, kundvård och CRM är några av de saker som studeras på respektive företag. Canal Digital AB och Boxer TV Access AB är de två distributörerna som undersöks och uppsatsen avgränsas till deras verksamhet i Sverige. Resultatet av undersökningen tyder på att distributörerna är väl medvetna om vikten av relationen till deras kunder. Flera exempel visar på att företagen arbetar aktivt för att vårda befintliga kunder och dessutom skapa nya relationer med kunder. Distributörerna arbetar med olika aktiviteter som inryms inom begreppet relationsmarknadsföring. Anpassade relationer till kunden medför även ett större engagemang och ansvar från distributörens sida eftersom kunden förväntar sig mer av en relation som uppfattas som personlig. I dagsläget kan digital-TV-abonnemang liknas med höginvolverande produkter, men digital-TV-övergången bidrar till en mättad marknad där trenden går mot att konkurrera om varandras kunder. För att undvika ett priskrig med låg involvering hos kunderna är det därför viktigt för distributörerna att kunna hitta nya sätt att differentiera sig.
48

Digital videoväxel / Digital video switch

Länger, Henrik, Eriksson, Olle January 2004 (has links)
This thesis discusses the possibilities to distribute digital video in a military vehicle. Today, an analogue system is used, which has a maximum capacity of eighteen video sources and the same number of monitors. The purpose of this thesis is to increase the systems capabilities regarding secure distribution and additional functions. Both software and hardware tests are made to investigate the features of the digital video standard MPEG-2. Both the coding delay and the image quality are of great interest. Another digital video standard, DV, is considered as an alternative to MPEG-2. Apart from different coding techniques, this work describes some distribution techniques like TCP/IP, DVB-C and USB.
49

Study and Implementation of DVB-H Receiver RF Module Using Dual-Conversion Architecture with Zero Second IF

Cheng, Kai-Jen 26 July 2005 (has links)
This thesis consisted of three parts. The first part discussed the RF architecture for the digital video broadcasting-handheld (DVB-H) system. The system planning and link budget of the RF receiver are included in this part. The effects of phase noise from local oscillator on the OFDM system are also considered here. The second part introduced the implementation of each stage for the designed receiver link. The measurement results for the entire RF receiver module are discussed in the third part, at which the link budget results are also presented for comparison. The sensitivity of the designed RF receiver module is -83 dBm, the dynamic range is more than 73 dB, and the power consumption is 345 mW. The designed RF receiver adopts the dual conversion with zero second IF architecture reduces the number of ICs, passive components, and the power consumption. In addition, the SAW filter is no longer required in the receiver link, and it is more suitable for the system-on-chip application.
50

An embedded, wireless-energy-harvesting platform (E-WEHP) for powering sensors using existing, ambient, wireless signals present in the air

Vyas, Rushi J. 27 August 2014 (has links)
The objective of this research is to develop an embedded, wireless, energy-harvesting prototype (E-WEHP) that can power on and sustain embedded sensing functions using the power present in ambient wireless signals in urban areas. This research is part of a bigger effort towards greening RF circuits and applications in order to reduce their pollution foot-print. Pollution due to modern electronics is primarily caused by non-biodegradable packaging waste and batteries that form a big part of most electronics. Electronic waste can especially be a nuisance in RFID and wireless sensors that are mass-produced and widely-used in consumer items, buildings, industries, agriculture and transportation. The first part of this research effort addresses the issue of minimizing electronic packaging waste by characterizing and using biodegradable substrates such as Paper and Perfluoropolymer (PFA) as a dielectric material in RF circuits. Towards this goal, the first of its kind active wireless sensor modules made of biodegradable paper substrate using a clean and novel inkjet-printing technology is developed and successfully operated in the 900 MHz free ISM band. The second and third part of this research effort addresses the issue of battery waste by investigating the use of ambient solar and wireless radiation for powering RF and embedded electronics for wireless localization and sensing applications without the use of batteries. The second part of this work presents a unique solar-powered tag called SOLTAG that combines solar cells along with an RFID-type powering mechanism to implement a very low-cost, battery-less, semi-passive wireless-tag but with a much longer range than passive EPC-Gen2 RFID tags. A GPS-like, low-cost, vehicle-tracking system based on a received-signal-strength-indication method using SOLTAGs in vehicles and a wireless network of Mica-motes is successfully developed and tested with accuracy down to 1.62 meters The third and main part of this research work presents a novel embedded-wireless-energy-harvesting-prototype (E-WEHP) that can successfully power-on and sustain sensing and M2M peripherals in a 16-bit microcontroller using the power present in ambient, wireless, Digital-TV signals without the use of batteries. This work involves an in-depth characterization of OFDM signals used in Digital-TV broadcasts in Tokyo and Atlanta along with the design and development of the E-WEHP hardware and firmware that exploits the multi-carrier nature of such TV signals for powering itself at a range of over 6 km from the TV broadcast sources. This work opens up the possibility of pervasively powering sensor motes for applications such as environmental sensing, smart homes, structural health monitoring, security and internet of things without the environmental and logistical cost of periodic battery replacement and disposal.

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