Programa de Pós-Graduação em Ciência da Computação - PPGCC/ICEN
URI Permanente desta comunidadehttps://repositorio.ufpa.br/handle/2011/2351
O Programa de Pós-Graduação em Ciência da Computação (PPGCC) é um programa do Instituto de Ciências Exatas e Naturais (ICEN) da Universidade Federal do Pará (UFPA). O PPGCC foi fundando em 2005 e visa ampliar a massa crítica na região, objetivando a produção de pesquisa científica na área, na busca de resolução de problemas regionais.
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Item Acesso aberto (Open Access) Aplicação de sensores virtuais na estimação da concentração dos parâmetros físico-químicos e metais em corpos d’água de reservatórios de hidrelétricas: um estudo de caso na Região Amazônica(Universidade Federal do Pará, 2014-10-23) RIBEIRO NETO, Benedito de Souza; OLIVEIRA, Terezinha Ferreira de; http://lattes.cnpq.br/6230804143692945; SILVEIRA, Antônio Morais da; http://lattes.cnpq.br/7549503749842625This research introduces the use of virtual sensors to estimate the concentration of physico-chemical parameters and metals in monitoring water quality of reservoirs Amazon through artificial neural networks (ANN) and images of remote sensing. A factor analysis of the variables considered in the study confirmed the relationship of the first factor with Secchi disk, Total Iron, PO4, Total P, TSS and Turbidity on a single factor, as these have a high reflectance and good energy absorption by satellite sensors. These elements were determined by ANN's, producing satisfactory results approach 100% between observed and estimated. The tests resulted in a good approximation, the first band Secchi disk depth, total Fe, STS, and turbidity of the water reservoir. In the specific case of the parameters PO4 and Total P, besides the problem of the small number of sampling stations available data and the variability inherent in the hydrological cycle of the region, it was found, through the interpretation of images, lack of similarities between the data used in training and validation of RNA. Overall, the study demonstrated the effectiveness of the application of virtual sensors in monitoring water quality of reservoirs in the Amazon by satellite imagery, providing a precise and less expensive alternative resources in the process of environmental monitoring.Item Acesso aberto (Open Access) Controle energeticamente eficiente de múltiplos saltos para redes de sensores sem fio heterogêneas utilizando lógica fuzzy(Universidade Federal do Pará, 2014-03-21) SILVA, Alexandre Márcio Melo da; SILVEIRA, Antônio Morais da; http://lattes.cnpq.br/7549503749842625This study presents a centralized control to elect appropriate Cluster Heads (CHs), assuming three levels of heterogeneity and multi-hop communication between Cluster Heads. The centralized control uses the k-means algorithm, responsible for the division of clusters and Fuzzy Logic to elect the Cluster Head and selecting the best route of communication between elected. The results indicate that the proposal offers great advantages, allowing us to select the most suitable nodes for group leaders at each round based on the Fuzzy System values, and also the use of Fuzzy Logic as a decision tool to implement multiple hops between CHs, since it minimizes the power dissipation of the selected CHs more distant from the collection point. The insertion of three levels of heterogeneity,corresponding to normal, advanced and super sensors, contributes considerably to increasing the period of network stability. Another great contribution obtained from the is the use of a central control in base station (BS) with advantages over local information processing in each node, a process usually found in traditional algorithms for electing CHs. The proposed solution proved that the election of the more efficient CH, considering its location and energy levels discrepancies, and also, the inclusion of new heterogeneity levels, allows to increase the networkstability period, ie, the period that the network is fully functional, greatly increasing the useful lifetime in heterogeneous WSN.Item Acesso aberto (Open Access) Um método fuzzy para programação de inspeções em transformadores baseado na análise de gases combustíveis e parâmetros físico-químicos do óleo isolante(Universidade Federal do Pará, 2014-10-24) PANTOJA, Márcia Priscila Furtado; OLIVEIRA, Terezinha Ferreira de; http://lattes.cnpq.br/6230804143692945; SILVEIRA, Antônio Morais da; http://lattes.cnpq.br/7549503749842625Power transformers using oil for insulation internal parts need periodic maintenance of a program aimed at detecting possible failures, such as deterioration of the winding insulation cellulose, short circuit between turns, gases dissolved in the oil due to its degeneration etc. Typically, preventive maintenance programs are used by companies for generation, transmission and distribution of electricity for avoiding these failures may result in removal of equipment from the electrical system, a situation that involves large financial losses, either by decreased billing at payment of penalties to the regulatory agency, as well as reduced system reliability. To avoid these types of losses, this paper presents a proposed solution using fuzzy approach, to assist the process of inspections programming in high power transformers (500kv), through the analysis of gases dissolved in insulating oil, obtained by the technique gas chromatography and physico-chemical analysis of the oil. We attempted to produce a solution that combines the results of traditional methods already established in the literature, with additional situations originating from the physico-chemical analysis of the oil and knowledge of experts in order to increase the effectiveness of such equipment inspection procedure. With this, any Electric Power System - SEP - that performs diagnostics on transformers by NBR 7274, tends to get a more accurate diagnosis, due to the association of physical-chemical analysis of the insulating oil with gas chromatography and knowledge tacit from specialists, enabling us to expand the base of original rules of that technical standard. All tests and the database used were from a laboratory of Chemistry of various electrical substations of an power company located in Barcarena - Pará - Brazil.