Diss. Linköping : Univ., 2004.

Diss. Uppsala : Univ., 2004.

In general the automotive electromagnetic environment is severe because of the presence of DC motors and ignition. In this thesis, electromagnetic interference and electromagnetic susceptibility are studied. This thesis is divided intro three parts. In Part I we introduce the specification of digital TV (DVB-T) in Taiwan. In Part 2 the reception of digital TV in vehicle and in laboratory is compared. The measurement in vehicle is conducted in order to understand the source of interference and how the disturbance occurs. The standard test in laboratory has to do with the transient susceptibility which is based on ISO 7637. We then analyze the implication of different pulses mandated in ISO 7637. The results are compared with those obtained in vehicular measurement. In Part 3 remedy is proposed to reduce the interference to digital TV.

<p>Det finns flera olika standarder inom digital-TV för att skapa interaktiva applikationer. Det här arbetet använder den öppna standarden MHP, Multimedia Home Platform, som utgångspunkt för att skapa programkod i programmeringsspråket Java. Arbetet handlar om att skapa ett program för MHPkompatibel utrustning som bekräftar en användares identitet via Smart cards, och levererar interaktiv, personlig information. Denna information levereras via tjänster som beskrivs i XML, och kommunicerar via HTTP med en server som skickar innehåll utifrån de preferenser som finns för denna användare.</p>

Det finns flera olika standarder inom digital-TV för att skapa interaktiva applikationer. Det här arbetet använder den öppna standarden MHP, Multimedia Home Platform, som utgångspunkt för att skapa programkod i programmeringsspråket Java. Arbetet handlar om att skapa ett program för MHPkompatibel utrustning som bekräftar en användares identitet via Smart cards, och levererar interaktiv, personlig information. Denna information levereras via tjänster som beskrivs i XML, och kommunicerar via HTTP med en server som skickar innehåll utifrån de preferenser som finns för denna användare.

Abstract Since the policy of National Information Infrastructure(NII) was brought up by U.S in 1993, medium, internet, telecommunication begins to converge. Industries around the world start to construct new services. The result all comes from the technology progress of broadband network. Cable companies only offer program services before, today they can play an important role in NII blueprint by their competence of last mile and large customer base. Cable companies can offer a lot of valued added service, especially as ITV service. From 90 years the discussion about how ITV will change the human life has never stopped. People living in Europe and U.S have had a chance watch ITV, but ITV in Taiwan seems still can¡¦t be possible. This research explore the straits by using Porter¡¦s competitive advantage of nations model and combines the first mover advantage theory by Wernerfelt, Birger and Karnani, Aneel. Lastly the research constructs a six frames analysis model. Major result of this research tells us each frame has many limiting factors to obstruct the development of cable ITV. And the limiting factors under the government, corporate, supported industry fames are more critical. The intervention by government is the most important limiting factor. Lack of demand, lack of technology, incorrect strategy and incorrect management are not the reason that ITV didn¡¦t happen in Taiwan. The research makes the conclusion that the straits in Taiwan are coming from the vicious circle caused by the government intervention and the bad situation in the cable industry. The research considers if we want the ITV carry out in Taiwan, We must stop the vicious circle. The government policy is the key point to solve the problem. So finally the research provides the four steps policy trying to change the situation of cable industry.

Mobile Digital TV (MDTV), the hybrid of Digital Television (DTV) and mobile devices (such as mobile phones), has introduced a new way for people to watch DTV and has brought new opportunities for development in the DTV industry. Nowadays, the development of the next generation MDTV service has progressed in terms of both hardware layers and software, with interactive services/applications becoming one of the future MDTV service trends. However, current MDTV interactive services still lack in terms of attracting the consumers and the service creation and implementation process relies too much on commercial solutions, resulting in most parts of the process being proprietary. In addition, this has increased the technical demands for developers as well as has increased substantially the cost of producing and maintaining MDTV services. In light of the aforementioned situation, the Thesis has contributed to this field, by proposing an innovative MDTV service creation and consumption system based on XHTML and Java ME. On the head-end it introduces a semi-automatic creation mechanism to facilitate a less technical and more efficient interactive service creation process. This enables designers and creative individuals to be actively involved in the MDTV service creation process and to develop interactive-rich MDTV service. On the client-end it employs an open-source software environment as the interactive service MDTV consumption platform, rendering the MDTV service implementation process as less proprietary as possible. Furthermore, the Thesis offers a discussion on the different MDTV interactive application models currently used and based on the proposed software, a novel MDTV service presentation method is further introduced and adopted instead of the Rich Media and ECMAScript based methods. Finally, a series of qualitative testing procedures have been implemented with regards to conducting an essential evaluation on the operability of the proposed software system.

Esta dissertação trata da equalização no domínio do tempo de sistemas de comunicações digitais baseados em orthoghonal frequency-division multiplexing (OFDM), normalmente referida na literatura técnica como equalização pré-FFT. Tais sistemas foram originalmente projetados de modo a não necessitar de equalização, porém podem se beneficiar com seu uso, como mostrado a seguir. Foi implementado, em programa de computador, um simulador não codificado do sistema de televisão digital terrestre utilizado na Europa, o digital video broadcasting (DVB-T), que é baseado em OFDM e se encontra implantado com sucesso há alguns anos. Diversas simulações foram executadas comparando o método tradicional de recepção do sistema DVB-T com a versão equalizada proposta. Foram utilizadas várias técnicas de processamento digital de sinais para simular: a geração do sinal, sua passagem por um canal de comunicação com multipercurso, presença de ruído branco Gaussiano aditivo, equalização LMS (Least Mean Square), entre outros fenômenos importantes. Para um firme embasamento, o trabalho apresenta estudos matemáticos sobre a teoria geral do OFDM, modelos de canais de comunicação e o princípio básico do algoritmo LMS. Tendo-se utilizado o DVB-T como estudo de caso prático, não poderia deixar de constar uma descrição técnica desse sistema em que são apresentados vários dos detalhes e problemas envolvidos na geração e recepção do sinal. Com a finalidade de posicionar o leitor histórica e tecnologicamente, o texto inclui ainda uma revisão dos principais fatos que marcaram o desenvolvimento do OFDM desde os estudos iniciais até os dias de hoje. / This dissertation deals with time-domain equalization of digital communications systems based on orthoghonal frequency-division multiplexing (OFDM), usually referred as pre-FFT equalization in the technical literature. Such systems were originally designed to require no time equalization but can profit from its use, as is shown in this work. An uncoded simulator of the OFDM-based European system for terrestrial digital television transmission, the digital video broadcasting (DVB-T), was implemented in software. Many simulations were run to compare the performance of the traditional DVB-T reception method with the equalized version proposed. Several digital signal processing techniques were used to simulate as diverse fenomena as: generation of the source signal, effect of multipath communications channels, presence of additive white Gaussian noise, LMS (Least Mean Square) equalization, among others. In order to develop a solid base, the work includes mathematical studies about the general OFDM theory, models of communications channels and the basic principle of operation of the LMS algorithm. Since the DVB-T was used as a practical study case, a technical description of the system is presented, in which many problems and aspects about its generation and reception are discussed. To provide the reader with a historical and technological insight on the subject, this work also includes a summary of the landmarks in the development of the OFDM since the first experiments.

A educação a distância é uma realidade bem vista por muitas instituições de ensino e pelo Ministério da Educação, sendo, portanto, fortemente incentivada. Essa modalidade vai muito além da alternativa de oferecer cursos de maneira confortável para alunos que não têm disponibilidade de tempo em horário comercial. Em alguns casos, esse é o único meio de atingir uma parcela da população que, apesar de encontrar-se isolada geograficamente, tem direito à educação básica de qualidade e gratuita como forma de garantir os seus direitos de cidadão. Este trabalho teve como objetivo investigar alternativas de software que visam oferecer apoio para a oferta de cursos na modalidade a distância. Como estudo de caso, foi delimitado um cenário real: o do estado do Amazonas, que conta com diversos esforços bem sucedidos no uso de educação a distância como alternativas para reduzir o isolamento geográfico. Para auxiliar os alunos e professores foi escolhido o ambiente Tidia-Ae, sendo que o maior enfoque foi dado à ferramenta DigaE e suas extensões, por possibilitarem a autoria de documentos multimídia interativos / Distance education is a education model that was recommend by many educational institutions and by the Education Ministry. This model goes beyond of offering courses in a comfortable way for students who do not have time available during business hours. In some cases, this is the only way to offer for a population that, although is geographically isolated, has the right to quality basic education and free as a way to guarantee their rights as citizens. This study aimed to investigate alternatives to the use of software tools aimed at providing support for the provision of courses in the distance. As a particular case, was delimited a real scenario: the Amazon state, which has several successful efforts in using distance education as alternatives to reduce the geographic isolation. To assist students and teachers were chosen environment Tidia-Ae, with the main focus was given to the DigaE tool and its extensions, for making possible the interactive multimedia document authoring

Os sistemas de televisão digital terrestre têm se estabelecido e expandido em várias regiões do mundo. A expectativa é de que 1,4 bilhão de televisores analógicas sejam substituídas por televisores e receptores digitais, também conhecidos como terminais de acesso. Daí a importância destes dispositivos que recebem e decodificam o sinal digital. Diante da diversidade de plataformas de hardware de diferentes fabricantes e perfis de terminais de acesso, existe a necessidade de um alto investimento para criar e desenvolver aplicações e software intermediário (Middleware) na medida em que existe a necessidade de diferentes códigos-fontes para cada uma das plataformas. Além desta fragmentação de implementações por conta das várias plataformas de hardware, existe a demanda crescente por desempenho e por soluções com um conjunto maior de funções. Para endereçar a estas questões, existem organizações, iniciativas e tecnologias emergentes em sistemas embarcados multimídia, algumas delas baseadas em componentes de software, que estão consolidando técnicas que podem ser aplicadas à estrutura de software de um terminal de acesso, dentre as quais destacamos a UHAPI, o M3W, o OpenMAX, a IOS e o GStreamer. Esta dissertação apresenta uma proposta de arquitetura de software denominada Arquimedia com base em uma análise comparativa destes trabalhos. Foram realizados e analisados ensaios de desempenho parciais para a validação da proposta. / The terrestrial digital television systems have been established and expanded by the worldwide. It is expected that 1.4 billion analog TV sets will be replaced by set-topboxes and digital receivers TV sets, also known as access terminals. This fact shows the relevance of these devices that receive and decode the digital signals. Given the diversity of the hardware platforms of different manufacturers and different set-topboxes profiles, there is a need for a major investment to create and develop applications and Middleware because for each hardware platform, different source codes need to be developed. Beside the fragmentation of implementations resulted by the diversity of hardware platforms, there is an increasing demand for performance and solutions with more functions. To address these questions, there are organizations, initiatives and emerging technologies, some of them based on software components, that are consolidating techniques that can be applied to the software stack of a set-top-box, from among we emphasize the UHAPI, M3W, IOS and GStreamer. This master thesis deals a comparative analysis of these technologies and presents a set-top-box software architecture proposal called Arquimedia. Performance tests were made and analyzed to validate the proposal.