842 resultados para Satelites artificiais em sensoriamento remoto


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Los sistemas fotovoltaicos son fuentes emergentes de energías renovables que generan electricidad a partir de la radiación solar. El monitoreo de los sistemas fotovoltaicos aislados proporciona información necesaria que permite a sus propietarios mantener, operar y controlar estos sistemas, reduciendo los costes de operación y evitando indeseadas interrupciones en el suministro eléctrico de zonas aisladas. En este artículo, se propone el desarrollo de una plataforma para el monitoreo de sistemas fotovoltaicos aislados en el Ecuador con el objetivo fundamental de desarrollar una solución escalable, basada en el uso de software libre, en el empleo de sensores de bajo consumo y en el desarrollo de servicios web en la modalidad ‘Software as a Service’ (SaaS) para el procesamiento, gestión y publicación de información registrada y la creación de un innovador centro de control solar fotovoltaico en el Ecuador.

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Dissertação (mestrado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Mecânica, 2015.

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Forecast is the basis for making strategic, tactical and operational business decisions. In financial economics, several techniques have been used to predict the behavior of assets over the past decades.Thus, there are several methods to assist in the task of time series forecasting, however, conventional modeling techniques such as statistical models and those based on theoretical mathematical models have produced unsatisfactory predictions, increasing the number of studies in more advanced methods of prediction. Among these, the Artificial Neural Networks (ANN) are a relatively new and promising method for predicting business that shows a technique that has caused much interest in the financial environment and has been used successfully in a wide variety of financial modeling systems applications, in many cases proving its superiority over the statistical models ARIMA-GARCH. In this context, this study aimed to examine whether the ANNs are a more appropriate method for predicting the behavior of Indices in Capital Markets than the traditional methods of time series analysis. For this purpose we developed an quantitative study, from financial economic indices, and developed two models of RNA-type feedfoward supervised learning, whose structures consisted of 20 data in the input layer, 90 neurons in one hidden layer and one given as the output layer (Ibovespa). These models used backpropagation, an input activation function based on the tangent sigmoid and a linear output function. Since the aim of analyzing the adherence of the Method of Artificial Neural Networks to carry out predictions of the Ibovespa, we chose to perform this analysis by comparing results between this and Time Series Predictive Model GARCH, developing a GARCH model (1.1).Once applied both methods (ANN and GARCH) we conducted the results' analysis by comparing the results of the forecast with the historical data and by studying the forecast errors by the MSE, RMSE, MAE, Standard Deviation, the Theil's U and forecasting encompassing tests. It was found that the models developed by means of ANNs had lower MSE, RMSE and MAE than the GARCH (1,1) model and Theil U test indicated that the three models have smaller errors than those of a naïve forecast. Although the ANN based on returns have lower precision indicator values than those of ANN based on prices, the forecast encompassing test rejected the hypothesis that this model is better than that, indicating that the ANN models have a similar level of accuracy . It was concluded that for the data series studied the ANN models show a more appropriate Ibovespa forecasting than the traditional models of time series, represented by the GARCH model

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Dissertação (mestrado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Elétrica, 2015.

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Dissertação (mestrado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Mecânica, 2016.

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Avaliámos a importância das bermas das estradas como áreas de refúgio para pequenos mamíferos, em paisagens Mediterrânicas intensivamente pastoreadas, e comparámos esta possível função das estradas como refúgio com o papel fundamental das galerias ripícolas como reservatórios de diversidade biológica. Para esse efeito, foram realizadas capturas de micromamíferos em dois segmentos de estrada e em duas ribeiras da região de Évora. Foram capturados 457 indivíduos de cinco espécies diferentes. Mus spretus foi a espécie mais capturada, seguida de Crocidura russula e Apodemus sylvaticus. M. spretus apresentou uma maior abundância nas bermas de estrada do que na vegetação ripicola, enquanto que a abundância de C. russula e A. sylvaticus era semelhante para ambos os habitats. O número de capturas das três espécies foi bastante superior dentro dos habitats lineares do que na matriz circundante. Os indivíduos de M. spretus eram maiores nas ribeiras, mas significativamente menores fora dos habitats lineares, e os indivíduos de C. russula apresentavam uma melhor condição corporal nas bermas das estradas. Tanto as estradas como as ribeiras exerceram um forte efeito de barreira aos movimentos dos micromamíferos. Concluímos então que as bermas das estradas actuam como habitat de refúgio em áreas sub-óptimas das paisagens Mediterrânicas. ABSTRACT: We assessed the importance of road verges as refuge areas for small mammals, in highly intensified grazed pastures on a Mediterranean landscape, and compared road function as refuge with the fundamental role of riparian galleries as reservoirs of biological diversity. For this purpose, a small mammal trapping study was undertaken on road verges and on small stream sides. We sampled two road segments and two streams in the vicinity of Évora, Portugal. We captured a total of 457 individuals of five different species. Mus spretus was the most common species captured, followed by Crocidura russula and Apodemus sylvaticus. M. spretus was more abundant on road verges than on riparian strips, whilst the abundance of C. russula and A. sylvaticus were similar in the two habitats. Captures of the three species were much higher inside both linear habitats than on the surrounding matrix. M. spretus were bigger on stream sites but significantly smaller outside the linear habitats and C. russula had better body conditions on roads. 8oth roads and streams exerted a strong barrier effect to small mammals' movements. We conclude that roadside verges act as refuge habitat in sub-optimal Mediterranean landscapes.

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This work aims to obtain a low-cost virtual sensor to estimate the quality of LPG. For the acquisition of data from a distillation tower, software HYSYS ® was used to simulate chemical processes. These data will be used for training and validation of an Artificial Neural Network (ANN). This network will aim to estimate from available simulated variables such as temperature, pressure and discharge flow of a distillation tower, the mole fraction of pentane present in LPG. Thus, allowing a better control of product quality

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In the artificial lift method by Electrical Submersible Pump (ESP), the energy is transmitted for the well´s deep through a flat electric handle, where it is converted into mechanical energy through an engine of sub-surface, which is connected to a centrifugal pump. This transmits energy to the fluid under the pressure form, bringing it to the surface In this method the subsurface equipment is basically divided into: pump, seal and motor. The main function of the seal is the protect the motor, avoiding the motor´s oil be contaminated by oil production and the consequent burning of it. Over time, the seal will be wearing and initiates a contamination of motor oil, causing it to lose its insulating characteristics. This work presents a design of a magnetic sensor capable of detecting contamination of insulating oil used in the artificial lift method of oil-type Electrical Submersible Pump (ESP). The objective of this sensor is to generate alarm signal just the moment when the contamination in the isolated oil is present, enabling the implementation of a predictive maintenance. The prototype was designed to work in harsh conditions to reach a depth of 2000m and temperatures up to 150°C. It was used a simulator software to defined the mechanical and electromagnetic variables. Results of field experiments were performed to validate the prototype. The final results performed in an ESP system with a 62HP motor showed a good reliability and fast response of the prototype.

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Artificial lakes must differ from natural lakes in important structural and functional aspects that need to be understood so that these ecosystems can be properly managed. The aim of this work was to test the hypothesis that the artificial lakes (impoundments) in the semi-arid region of the Rio Grande do Norte State are more eutrophic and turbid and have different trophic structure when compared to the natural coastal lakes that occur in the humid eastern coast of the State. To test this hypothesis, 10 natural lakes and 8 artificial lakes with about 100 ha were sampled between September and November 2005 for the determination of some limnological variables and the abundance of the main fish species, which were grouped in three trophic guilds: facultative piscivores, facultative planktivores and omnivores. The results show that the artificial lakes had significantly higher concentrations of total nitrogen, total phosphorus, chlorophyll a , total and volatile suspended solids than the natural lakes. Results also show that the values of pH, total alkalinity, electric conductivity, turbidity as well as the coefficient of vertical attenuation of light were significantly higher in the artificial lakes than in the natural lakes. In the artificial lakes, the abundance of facultative planktivores was significantly higher, while the abundance of facultative piscivores significantly lower than in the natural lakes. There was no significant difference in the abundance of omnivorous fish between the two types of lakes. These results suggest that the increase in turbidity together with the other changes in the water quality of the artificial lakes, modifies the trophic structure of the fish communities reducing the importance of piscivores and the length of the food chains

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Resumen: Se realiza una revisión sobre los antecedentes de las Redes Neuronales Artificiales (RNA) como método de análisis de bases de datos medioambientales, aplicado en las diversas áreas de la Ingeniería Ambiental en general y de Impacto Ambiental en particular. Se describe como ejemplo, la aplicación de RNA en los algoritmos de inversión de datos obtenidos por sensado remoto satelital, para la medición de variables geofísicas

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Trecho da Nota Técnica: "Com o avanço do uso da tecnologia digital nos sistemas de fornecimento de energia elétrica, começa a surgir o que se convencionou chamar de quarta geração desses sistemas, ou seja, as chamadas smart grids, caracterizadas pelo uso intensivo de equipamentos digitais, de telecomunicações, de sensoriamento e operação remotos de instalações, e de tecnologia de informação (TI), adicionalmente às instalações físicas de geração, transmissão e distribuição de energia elétrica existentes." Consultoria Legislativo - Área XII Recursos Minerais, Hídricos e Energéticos.

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En la historia de la vida sobre la Tierra, el capítulo que trata sobre el almacenamiento y conservación de las plantas se escribe en los dominios del herbario. El herbario posee los ejemplares que documentan la exploración del hombre sobre la superficie terrestre, de manera que no sólo existe el documento escrito que narra la historia del explorador sino que tenemos el privilegio de tocar esos objetos o especímenes. Así, cada herbario en el mundo posee un tesoro escondido de especímenes históricos que son el fiel testigo de las hazañas de un investigador o de una exploración a algún lugar remoto. En las últimas dos décadas el medio en el que se desarrollan los herbarios y sus colecciones han subrido cambios muy significativos, los que a su vez han ejercido presiones sobre quienes manejan las colecciones. Algunos de estos cambios son la disminución de los aportes económicos a los herbarios, el cambio en el uso de la evidencia morfológica hacia la molecular en los estudios sistemáticos y la pérdida acelerada de la biodiversidad que trae aparejada la necesidad urgente de realizar inventarios florísticos. En una era de extinción de biotas, las colecciones valiosas como son hoy día, serán aún más valiosas en los años por venir. Las colecciones representan el testigo imprescindible para la ciencia y el vehículo para llegar a las posibles soluciones. Es por ello que el conocimiento del significado, valor y uso del herbario y sus colecciones reviste una vital importancia para la ciencia y para la sociedad.