977 resultados para Telecomunicações


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O G.fast é um novo padrão da União Internacional de Telecomunicações que almeja atingir 1 Gb/s sobre enlaces de cobre curtos, utilizando freqüências de até 212 MHz. Essa nova tecnologia requer modelos paramétricos precisos de cabo para fins de projeto, simulação e testes de avaliação de desempenho. A maioria dos modelos de cabo de cobre foram desenvolvidos focando o espectro VDSL - isto é, freqüências de até 30 MHz - e adotam suposições que são violadas quando a faixa de freqüência é estendida para freqüências G.fast. Esta tese apresenta novos modelos de cabo simples e causais capazes de caracterizar com precisão enlaces de cobre compostos por segmentos individuais ou múltiplos, tanto no domínio do tempo quanto no domínio da freqüência. Resultados utilizando as topologias de referência do padrão G.fast mostram que, além de serem precisos, os novos modelos são atrativos devido ao baixo custo computacional e fórmulas fechadas para ajuste de seus parâmetros junto a dados medidos.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Engenharia Elétrica - FEIS

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The restructuring of the state productive sector of the central government of China is a phenomenon that has occurred since 1978, and is not yet complete. In a centrally planned economy, China's government introduced a series of economic and social transformations in order to modernize the country's economic structure. The flagship of these reforms was the reintroduction of a market economy, living side by side with a strong state control over key economic variables of the country. In this process, there was a restructuring of ownership of enterprises by means of collectivization, the creation of joint stock companies, establishing joint ventures with foreign companies or privatization. The result of this process was the creation of a set of holding companies that operate in strategic sectors of China's economy such as energy, transport, telecom, capital goods and defense. Within this brief article we will focus on the process of opening up and modernization as the expression of a national project that sought to understand the changes in the international economy and sought to adapt the demographic characteristics of China and productive so you get the best out of globalization.

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This work focuses on the study of video compression standard MPEG. To this end, a study was undertaken starting from the basics of digital video, addressing the components necessary for the understanding of the tools used by the video coding standard MPEG. The Motion Picture Experts Group (MPEG) was formed in the late '80s by a group of experts in order to create international standards for encoding and decoding audio and video. This paper will discuss the techniques present in the video compression standard MPEG, as well as its evolution. Will be described in the MPEG-1, MPEG-2, MPEG-4 and H.264 (MPEG-4 Part 10), however, the last two will be presented with more emphasis, because the standards are present in most modern video technologies, as in HDTV broadcasts

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The expansion of the energy matrix is a matter of great importance since the recent problems facing the country in this sector, such as rationing mobilized in 2001. Moreover, there is also concern with global sustainable development. Brazil is producing about 64 million cubic meters of biogas per day, but only a small percentage of this total is harnessed as an energy resource. Compounders are considered potential, for example, landfill energy (LE) and sewage treatment plants (STP), which can be adapted to produce biogas and market them. The work focuses its studies on biogas produced by these small and medium compounders. Are proposed and studied the following alternatives for the utilization of biogas energy: generation and sale of electricity through the installation of a small power station within the landfill, and purification and marketing of gas, whose price will be a consideration on the price of natural gas, taking into account the percentage of methane present in the biogas. Trade ensures that gas plus a destination ecologically appropriate to it, taking advantage of its energy

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Technological development in the IT and telecommunications sectors have transformed the way organizations communicate with their audiences. Social Media allow the exchange of information instantaneously, in a communication from many to many. With few studies in the area, many companies venture into the social media without a strategy and a generally end up denigrating their image itself. Thus, this study was conceived from the idea of contributing, analytically, based on the main concepts of Public Relations so the organizations effectively take advantage of their online presence to generate relationships, more specifically, on Twitter.Twitter is a social media with a mature public, requiring dynamics of information and quick answers, based on dialogue, referring to the idea of text messages (SMS). To better expose the results of this research, three organizations with expertise in twitter were chosen: Bradesco , Positivo Informática and Ponto Frio. The choice of case studies was based on the different segments that each one operates and that they are large companies with reputable commercial operations in the Brazilian scenario. To analyze their profiles, several authors were studied, like Fábio França, Maria Aparecida Ferrari, Margarida Kunsch e Marlene Machiori.The intent of the analysis of the Twitter profiles of these organizations is to understand whether they are using strategies for creating and maintaining relationships with your followers and how this occurs from specific categories, as other companies have committed serious errors and impairing their business because of mismanagement in social media. Therefore, the profiles were analyzed from the netnográfica methodology. As a result, it was observed that organizations have not yet developed the character of relationships in social media , treating this channel as another advertising channel It was observed that Positivo Informática has no specific strategy for Twitter...

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The main objective is to create a software, using C++ language, for reading and exhibiting in a graphic an Electrocardiogram (ECG) wave. The data is recorded as a FM modulated signal and compressed using Adaptive Differential Pulse Code Modulation (ADPCM). The signal have this characteristics because it was acquired using an experimental equipment, this equipment is the result of research made by the professor who supervised this work. FM demodulation techniques in discrete time, discrete filters and digital signal processing are some of the topics that can be found in this essay. Some concepts about the human heart and about ECG waves are also briefly introduced. These concepts are necessary for understanding the final evaluation of the software performance. The development is partly made using MATLAB. Most of the functions that are used on the software are first tested and designed in MATLAB environment. In the end, an evaluation is done comparing the results that are expected with the ones that MATLAB presents and the ones that the developed software presents

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O rápido crescimento do mercado de dispositivos eletrônicos portáteis, com aplicações em diferentes áreas (telecomunicações, medicina, engenharia), criou uma grande demanda por fontes de potência compactas leves e, sobretudo, de baixo custo. Essa demanda levou ao desenvolvimento de tecnologia de filmes finos nanoestruturados para a obtenção de componentes eletroeletrônicos, por exemplo, memórias de computador. Estes dispositivos são empregados em “notebooks”, circuitos integrados, telefones celulares. O estudo de cristalização de filmes finos ferroelétricos nanoestruturados será feito através da cristalização induzida por rotas convencionais tal como cristalização em forno mufla. A modulação entre os diferentes cátions (Pb, Ca e Ba) para formar o sistema Pb1-x(Ca,Ba)xTiO3 serão analisadas, visando obter filmes com propriedades compatíveis para uso em memórias ferroelétricas. Para isso, os filmes finos serão depositados em substratos adequados controlando-se a homogeneidade química, a microestrutura e a interação filme-substrato

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Desde os trabalhos de Claude Shannon, em 1948, o avan¸co tecnológico na área das telecomunicações tem sido notável. Um grande problema na transmissão de mensagens por algum canal sempre residiu no fato de que, ao atravessar o canal, o conteúdo transmitido sofre distorções e chega modificado ao destinatário, o que impossibita a sua leitura correta. Graças ao trabalho de Shannon, esse problema obteve uma solução. Para identificar erros na transmissão de uma mensagem e corrigí-los, criaram-se os códigos corretores de erros, dos quais trataremos neste artigo, com destaque à classe dos códigos lineares. Para tanto, serão dados alguns resultados importantes relacionados aos corpos finitos, que são estruturas algébricas importantes sobre as quais se constroem esses códigos.

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Pós-graduação em Engenharia Mecânica - FEIS

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Pós-graduação em Ciência da Informação - FFC

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Pós-graduação em Engenharia Mecânica - FEG