Redes inteligentes de distribuição de energia fornecem serviços com o potencial de aumentar a eficiência energética e a qualidade de vida da sociedade, mas possuem requisitos severos de tempo de resposta, confiabilidade, escalabilidade e QoS. As chaves ópticas são dispositivos comutadores de caminhos em fibras ópticas popularmente utilizados para trocas físicas de rotas. Neste trabalho sugere-se utilizar estes dispositivos para ativamente reorganizar uma rede com o objetivo de diminuir a latência de comunicação, visando atender aos requisitos de comunicações dos serviços de redes inteligentes. Foram estudadas as características de protocolos de roteamento conhecidos e aplicou-se o algoritmo de Dijkstra na criação de quatro heurísticas de otimização dos caminhos máximos em redes com chaves ópticas. Simulações realizadas mostram que as heurísticas propostas reduzem o número de saltos nos caminhos máximos, levando à redução de latência. É sugerida a continuação deste estudo aperfeiçoando as heurísticas propostas com outros mecanismos de otimização e diferentes métricas, como redução de congestionamento de tráfego e de consumo de energia na rede. / Smart grid networks provide services with the potential to increase energy efficiency and the quality of life of society, but have strict requirements regarding response time, reliability, scalability and QoS. The optical switches are fiber optic switching devices commonly used for physical route changing. In this study, it is suggested to use these devices to actively rearrange a network in order to reduce the communication latency, to meet the communications requirements of smart grid services. The characteristics of known routing protocols have been studied and the Dijkstra algorithm has been applied at the creation of four heuristics that aim to optimize the maximum paths in networks with optical switches. The simulations show that the heuristics reduce the maximum number of hops in the paths, leading to reductions in latency. It is suggested the continuation of this study improving the heuristics with other optimization engines and different metrics, such as reducing traffic congestion and energy.

Indiana University-Purdue University Indianapolis (IUPUI) / Non-invasive surface recording of bioelectric potentials continues to be an essential tool in a variety of research and medical diagnostic procedures. However, the integrity of these recordings, and hence the reliability of subsequent analysis, diagnosis, or recommendations based on the recordings, can be significantly compromised when various types of noise are allowed to penetrate the recording circuit and contaminate the signals. In particular, for bioelectric phenomena in which the amplitude of the biosignal is relatively low, such as muscle activity (typically on the order of millivolts) or neural traffic (microvolts), external noise may substantially contaminate or even completely overwhelm the signal. In such circumstances, the tissue-electrode interface is typically the primary point of signal contamination since its impedance is relatively high compared to the rest of the recording circuit. Therefore, in the recording of low-amplitude biological signals, it is of paramount importance to minimize the impedance of the tissue-electrode interface in order to consistently obtain low-noise recordings. The aims of the current work were (1) to complete the development of a set of tools for rapid, simple, and reliable full-spectrum characterization and analytical modeling of the complex impedance of the tissue-electrode interface, and (2) to characterize the interfacial impedance and signal-to-noise ratio (SNR) at the surface of the skin across a variety of preparation methods and determine a factor or set of factors that contribute most effectively to the reduction of tissue-electrode impedance and noise contamination during recording. Specifically, we desired to test an initial hypothesis that surface abrasion is the principal determining factor in skin preparation to achieve consistently low-impedance, low-noise recordings. During the course of this master’s study, (1) a system with portable, battery-powered hardware and robust acquisition/analysis software for broadband impedance characterization has been achieved, and (2) the effects of skin preparation methods on the impedance of the tissue-electrode interface and the SNR of surface electromyographic recordings have been systematically quantified and compared in human subjects. We found our hypothesis to be strongly supported by the results: the degree of surface abrasion was the only factor that could be correlated to significant differences in either the interfacial impedance or the SNR. Given these findings, we believe that abrasion holds the key to consistently obtaining a low-impedance contact interface and high-quality recordings and should thus be considered an essential component of proper skin preparation prior to attachment of electrodes for recording of small bioelectric surface potentials.

Na busca por novas opções para a constituição da matriz energética brasileira, os Sistemas Fotovoltaicos Conectados à Rede Elétrica (SFVCR) configuram-se como uma alternativa para os centros urbanos, pois permitem a geração de energia de modo distribuído, ou seja, no próprio local onde esta será consumida e, permitem também, com que o excedente de energia produzido seja injetado na rede elétrica. Diante da perspectiva de instalar o SFVCR, o objetivo desta pesquisa foi o de elaborar um estudo específico, detalhado e atualizado sobre o potencial de geração de energia na cidade de Curitiba. Neste trabalho apresenta-se o estudo de caso de seis sistemas fotovoltaicos instalados em Curitiba, os quais tiveram seus Índices de Mérito – Produtividade, Taxa de Desempenho e Fator de Capacidade - avaliados, a partir dos dados de geração de energia elétrica destes sistemas, e dos dados de irradiação obtidos do Instituto Nacional de Meteorologia (INMET). O estudo revelou que, até abril de 2017, o estado do Paraná possuía 810 SFVCR em operação, correspondendo a um total de 5MW e, a cidade de Curitiba 170 SFVCR – 865 kW em operação, sendo que 80% dos sistemas estão instalados em residências. Outro fato interessante é que 98% desses sistemas usam módulos com tecnologia de silício policristalino, 75% aplicam inversores monofásicos e, 95% desses inversores não possuem transformadores, pois dessa forma as perdas no processo de conversão são menores, além desses equipamentos serem mais compactos e possuírem tecnologia mais avançada do que os inversores com transformador. Constatou-se que a principal tendência do mercado de energia fotovoltaica é empregar inversores sem transformador. Além disso, os estudos realizados revelaram que a escolha do inversor e o modo de instalação dos painéis fotovoltaicos são fatores determinantes para maximizar o desempenho do sistema fotovoltaico. Os resultados desta pesquisa mostram a importante contribuição que os SFVCR podem trazer na geração de energia de modo distribuído e dessa forma, podem colaborar para a elaboração de políticas públicas com o intuito de incentivar projetos e pesquisas na área de energia fotovoltaica, visando à disseminação do uso dessa fonte renovável no país. / In the search for new options for the establishment of the energy matrix of Brazil, the Grid-Connected Photovoltaic Systems (SFVCR) are configured as an alternative to urban centers, because they allow the power generation at distributed mode, that is, generate energy at the place where it will be consumed and inject the surplus energy into the network. Faced with the prospect of installing Grid-Connected Photovoltaic System, the objective of this research is to characterize this type of photovoltaic system and also, analyze the results in terms of productivity parameters, such as Yield, Performance Ratio and Capacity Factor of six grid-connected systems that are installed in Curitiba. The radiation data used to calcute those parameters has been acquired from Instituto Nacional de Meteorologia (INMET). This paper highlight that the Parana state has 810 SFVCR (until April 2017) in operation, which stands for 5MW and Curitiba has 170 SFVCR, 865 kW in operation, and 80% of them are installed in residences. In addition, 98% of those systems use multicrystalline modules, 75% use single phase inverters and 95% of these use inverters transformerless, because the losses in the conversion process are reduced and the equipments are more compact and have more technology than the inverters with transformer. So, the main trend of photovoltaic energy market is to use transformerless inverters. The results obtained shows that the inverters’choice and the installation mode of the photovoltaic modules are important factors to maximize the photovoltaic system’s performance. In the end, the results demonstrates that the SFVCR contribute to distributed power generation and should be use in the elaboration of public policies with the purpose of encouraging projects and research in the photovoltaic energy’s area, aiming the dissemination of this renewable source of energy in Brazil.