933 resultados para Power distribution network
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Trata-se de um caso para ensino descritivo sobre o voluntariado em organizações da sociedade civil sem fins lucrativos na área da saúde. Identificado como um dos vértices da rede de governança colaborativa dos prestadores de serviço em saúde pública. No contexto do caso são apresentados conceitos de liderança voluntária e tomada de decisão em uma organização da sociedade civil sem fins Lucrativos na área da saúde. Análise de atores de governança colaborativa como complemento de qualidade na prestação de serviços para saúde pública é o foco do caso de ensino apresentado. O caso traz como pontos para reflexão e debate sobre a força motriz e o elemento de sustentação da rede colaborativa da saúde pública e a importância deste arranjo de relação Sociedade-Estado. O caso é indicado para estudantes de administração pública, políticas públicas, governança colaborativa, gestão social e áreas e afins.
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This work evaluates the organization of the legislative activities and the decision-making process within the Legislative Assembly of RN, emphasizing the role of ruling institutions on the Legislative Power working, as well as the structure of its decisions. The organization and the production of the decision-making process inside the Legislative Assembly will be seen along with how institutional norms determine the nature of the legislative process and influence his legal production. The period under study extends from 1990/94 to 1994/97 legislatures. The work is divided in three parts. The first analyzes the legislative process, the role of legal production, the nature of the legislation produced during the time referred and the role of the decisory instances: the directive Table, the leaders collegiate and the permanent commissions; the second part will present the results of questionnaires made to the deputies about their perspective concerning the actual power structure, as well as a more desirable power distribution among different decisory instances in the Assembly. At last, part three will focus on the Executive power role exerted on the legislative process, analyzing how it makes use of his initiating and veto prerogatives, via the study of some laws sanctioned in 1990-1997
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A madeira roliça possui grande emprego nas construções civis, desempenhando a função de vigas, colunas, fundações, postes para distribuição de energia elétrica, entre outras, apresentando a vantagem de não ser processada, como é o caso da madeira serrada. O projeto envolvendo elementos roliços requer, além de outras variáveis estruturais, o conhecimento do módulo de elasticidade. No Brasil, os documentos normativos que tratam da determinação das propriedades de rigidez e resistência para peças roliças de madeira estão em vigência há mais de vinte anos sem revisão técnica. A madeira roliça, por geralmente possuir eixo com curvatura não nula, pode apresentar, segundo a posição da peça no ensaio de flexão, valores diferentes do módulo de elasticidade. Este trabalho tem como objetivo analisara influência da posição de peças roliças de madeira de Eucalyptus grandis na determinação do módulo de elasticidade na flexão. O ensaio de flexão utilizado é o de três pontos, sendo cada peça avaliada em duas posições distintas, definidas mediante o giro da seção transversal em torno do eixo. Os resultados encontrados indicam a necessidade do ensaio de flexão em, pelo menos, duas posições distintas da peça.
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This work presents the cashew nuts chain in the State of Rio Grande do Norte between 1960 and 2009. The main purpose of this research was to find the reason of the low productivity of the cashew nut in this state, identifying in the cashew's chain production the struggling points which were limiting the commerce of this product through the distribution network. Therefore, the Supply Chain Management was used as a logistic analysis methodology, focusing on relationships management between the nodes of this chain, from the producer until the final customer. Many problems were found: first, the precarious production conditions of the small producer don't lead to reach the demanded productivity by the market. The distance, the lack of communication of the small producers among themselves and an archaic way of dealing with their businesses, may be an explanatory reason for this problem, considering that those factors are the main elements which contribute for the weakening of the small producer placed in the productive chain. Another spotted point was that the business-oriented relationship between the producer and the local trader does not allow the small producer's economical development, which interferes in any technological investment to reach a good quality production that fulfills the market demand. And also, the fact that there is a tendency of the final costumer to require lower prices day-byday, forcing a pressure on the nodes transferring to the other and successively until arriving at the producer who inevitably is suffering the biggest impacts from this mentioned pressure.
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The reconfiguration of a distribution network is a change in its topology, aiming to provide specific operation conditions of the network, by changing the status of its switches. It can be performed regardless of any system anomaly. The service restoration is a particular case of reconfiguration and should be performed whenever there is a network failure or whenever one or more sections of a feeder have been taken out of service for maintenance. In such cases, loads that are supplied through lines sections that are downstream of portions removed for maintenance may be supplied by the closing of switches to the others feeders. By classical methods of reconfiguration, several switches may be required beyond those used to perform the restoration service. This includes switching feeders in the same substation or for substations that do not have any direct connection to the faulted feeder. These operations can cause discomfort, losses and dissatisfaction among consumers, as well as a negative reputation for the energy company. The purpose of this thesis is to develop a heuristic for reconfiguration of a distribution network, upon the occurrence of a failure in this network, making the switching only for feeders directly involved in this specific failed segment, considering that the switching applied is related exclusively to the isolation of failed sections and bars, as well as to supply electricity to the islands generated by the condition, with significant reduction in the number of applications of load flows, due to the use of sensitivity parameters for determining voltages and currents estimated on bars and lines of the feeders directly involved with that failed segment. A comparison between this process and classical methods is performed for different test networks from the literature about networks reconfiguration
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The opening of the Brazilian market of electricity and competitiveness between companies in the energy sector make the search for useful information and tools that will assist in decision making activities, increase by the concessionaires. An important source of knowledge for these utilities is the time series of energy demand. The identification of behavior patterns and description of events become important for the planning execution, seeking improvements in service quality and financial benefits. This dissertation presents a methodology based on mining and representation tools of time series, in order to extract knowledge that relate series of electricity demand in various substations connected of a electric utility. The method exploits the relationship of duration, coincidence and partial order of events in multi-dimensionals time series. To represent the knowledge is used the language proposed by Mörchen (2005) called Time Series Knowledge Representation (TSKR). We conducted a case study using time series of energy demand of 8 substations interconnected by a ring system, which feeds the metropolitan area of Goiânia-GO, provided by CELG (Companhia Energética de Goiás), responsible for the service of power distribution in the state of Goiás (Brazil). Using the proposed methodology were extracted three levels of knowledge that describe the behavior of the system studied, representing clearly the system dynamics, becoming a tool to assist planning activities
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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In this paper we deal with the problem of feature selection by introducing a new approach based on Gravitational Search Algorithm (GSA). The proposed algorithm combines the optimization behavior of GSA together with the speed of Optimum-Path Forest (OPF) classifier in order to provide a fast and accurate framework for feature selection. Experiments on datasets obtained from a wide range of applications, such as vowel recognition, image classification and fraud detection in power distribution systems are conducted in order to asses the robustness of the proposed technique against Principal Component Analysis (PCA), Linear Discriminant Analysis (LDA) and a Particle Swarm Optimization (PSO)-based algorithm for feature selection.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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This paper analyses the impact of choosing good initial populations for genetic algorithms regarding convergence speed and final solution quality. Test problems were taken from complex electricity distribution network expansion planning. Constructive heuristic algorithms were used to generate good initial populations, particularly those used in resolving transmission network expansion planning. The results were compared to those found by a genetic algorithm with random initial populations. The results showed that an efficiently generated initial population led to better solutions being found in less time when applied to low complexity electricity distribution networks and better quality solutions for highly complex networks when compared to a genetic algorithm using random initial populations.
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This work considers a problem of interest in several technological applications such as the thermal control of electronic equipment. It is also important to study the heat transfer performance of these components under off-normal conditions, such as during failure of cooling fans. The effect of natural convection on the flow and heat transfer in a cavity with two flush mounted heat sources on the left vertical wall, simulating electronic components, is studied numerically and experimentally. The influence of the power distribution, spacing between the heat sources and cavity aspect ratio have been investigated. An analysis of the average Nusselt number of the two heat sources was performed to investigate the behavior of the heat transfer coefficients. The results obtained numerically and experimentally, after an error analysis, showed a good agreement.
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In this paper, an expert and interactive system for developing protection system for overhead and radial distribution feeders is proposed. In this system the protective devices can be allocated through heuristic and an optimized way. In the latter one, the placement problem is modeled as a mixed integer non-linear programming, which is solved by genetic algorithm (GA). Using information stored in a database as well as a knowledge base, the computational system is able to obtain excellent conditions of selectivity and coordination for improving the feeder reliability indices. Tests for assessment of the algorithm efficiency were carried out using a real-life 660-nodes feeder. © 2006 IEEE.
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This paper presents a general modeling approach to investigate and to predict measurement errors in active energy meters both induction and electronic types. The measurement error modeling is based on Generalized Additive Model (GAM), Ridge Regression method and experimental results of meter provided by a measurement system. The measurement system provides a database of 26 pairs of test waveforms captured in a real electrical distribution system, with different load characteristics (industrial, commercial, agricultural, and residential), covering different harmonic distortions, and balanced and unbalanced voltage conditions. In order to illustrate the proposed approach, the measurement error models are discussed and several results, which are derived from experimental tests, are presented in the form of three-dimensional graphs, and generalized as error equations. © 2009 IEEE.