94 resultados para Lunar missions
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Pós-graduação em Física - FEG
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The use of mobile robots turns out to be interesting in activities where the action of human specialist is difficult or dangerous. Mobile robots are often used for the exploration in areas of difficult access, such as rescue operations and space missions, to avoid human experts exposition to risky situations. Mobile robots are also used in agriculture for planting tasks as well as for keeping the application of pesticides within minimal amounts to mitigate environmental pollution. In this paper we present the development of a system to control the navigation of an autonomous mobile robot through tracks in plantations. Track images are used to control robot direction by pre-processing them to extract image features. Such features are then submitted to a support vector machine and an artificial neural network in order to find out the most appropriate route. A comparison of the two approaches was performed to ascertain the one presenting the best outcome. The overall goal of the project to which this work is connected is to develop a real time robot control system to be embedded into a hardware platform. In this paper we report the software implementation of a support vector machine and of an artificial neural network, which so far presented respectively around 93% and 90% accuracy in predicting the appropriate route. (C) 2013 The Authors. Published by Elsevier B.V. Selection and peer review under responsibility of the organizers of the 2013 International Conference on Computational Science
Influence of abutment-to-fixture design on reliability and failure mode of all-ceramic crown systems
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Besides storing, the culture and science institutions in charge of the of Brazilian writers’ personal archives play such an important role on the organization and representation of the country’s literary information. In general, the target public for these collections is composed by researchers from the field of Literature once the documents produced by the writers throughout his/her life and career constitute primary research source for the artistic, historical and literary investigation. However, it is still convenient to stand out those users with no academic instruction, whose interest in such collections is justified by their looking up to the individual. In this sense, literary memory places, such as the Brazilian Literature Archive Museum – AMLB (RJ) -, the Brazilian Literature Academy – ABL – (RJ) and the Brazilian Studies Institute – IEB – (SP) turn out to be responsible for offering access to the literary archives and literary information. Thus, it is necessary to consider that databases demonstrate themselves as utter disseminators of the preservation and diffusion of the literary memory, coming up with several possibilities for cultural and scientific action in Literature. This study focuses on showing the contributions of databases towards the literary archives, the challenges and perspectives observed according to the mentioned institutions’ reality, in whose missions the discourse of the literary memory preservation is inserted.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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A captura do caranguejo-uçá (U. cordatus) constitui uma das principais fontes de alimento e renda para muitas comunidades litorâneas, sendo considerada uma das atividades extrativistas estuarinas mais antigas no Brasil. O Município de Cananéia (SP) faz parte da Área de Proteção Ambiental de Cananéia-Iguape-Peruíbe (APA/CIP), possuindo 72 km² de manguezais, que a partir de 1990 passaram a receber uma maior pressão de explotação dessa espécie pela introdução da “redinha”, um petrecho de pesca proibido por lei nas regiões sudeste-sul brasileiras (Portaria IBAMA nº 52/2003). O presente estudo visa avaliar a produção do recurso caranguejo-uçá em Cananéia (SP), identificando seu padrão explotatório recente, com vistas à sustentabilidade futura das capturas. Na avaliação foram utilizadas planilhas de dados disponibilizadas pelo Instituto de Pesca (APTA/SAA-SP), referentes aos anos de 2009 e 2010, além do acompanhamento de uma das rotinas de coleta, com realização de biometria dos caranguejos capturados. Os dados evidenciam que o uso da “redinha” apresenta falha de recolhimento de 3,6%, num total de 86,4% de produtividade, que permanecem nos manguezais, podendo (ou não) ser recolhidas por outro catador. Os dados das planilhas do IP/APTA/SAA-SP foram avaliados segundo o modelo linear generalizado (GLM), com base em seis variáveis (unidade produtiva, mês de captura, ano, fase lunar, setor produtivo e período reprodutivo da espécie), das quais o conhecimento empírico dos catadores, ano da pescaria e o setor produtivo, foram as variáveis que mais influenciaram as mudanças observadas na captura por unidade de esforço (CPUE) da espécie. Além disso, foram verificadas produtividades diferenciadas na extração de caranguejos entre os cinco setores estabelecidos, que caracterizam o Estuário de Cananéia nos dois anos analisados. A experiência na condução... (Resumo completo clicar acesso eletrônico abaixo)
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The common vampire bat Desmodus rotundus has as main food source blood of medium and large sizes mammals, but sporadically is observed feeding on birds, causing occasionally excessive bleeding and economic losses. Due to this D. rotundus is one of the most studied species of bats in the Americas. Once known that the lunar clarity might influence the nocturnal activities of the common vampire bats, the present study was carried out to know the behavior and schedules of emergencies and returns of bats to the shelter, its social behavior at the shelter´s entrance, especially of the dominant male, and the size and composition of the colony in different moon phases. The colony was composed by 105 individuals (65 females and 40 males) harboring in a hollow-tree of Farm Edgardia in Botucatu Municipality, State of São Paulo. Through the eight filming sessions, two for each moon phase, it was possible to observe that the distribution of emergences and returns to the shelter thought the night followed a specific pattern for each moon phase. The greatest number of emerging bats occurred in periods in which the moon was not born yet and the largest number of returns just before moon has been reached its maximum level in the sky. Therefore, the time period that bats are staying outside the shelter seems to be directly influenced by lunar light. This factor can influence the social activity of the colony and, in particular, the dominant male, who remains still on tree’s trunk, near the entrance of the shelter with greater frequency during periods of low moon light
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Não disponível
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Cosmic radiation has been identi ed as one of the main hazard to crew, aircraft and sensitive equipments involved in long-term missions and even high-altitude commercial ights. Generally, shields are used in spatial units to avoid excessive exposure, by holding the incident radiation. Unfortunatelly, shielding in space is problematic, especially when high-energy cosmic particles are considered, due to the production of large number of secondary particles, mainly neutrons, protons and alpha particles, caused by spallation reactions and quasi-elastic processes of the corpuscular radiation with the shield. Good parameters for checking the secondary particle production at target material are diferential cross section and energy deposited in the shield. Addition experiments, some computer codes based on Monte Carlo method show themselves a suitable tool to calculate shield parameters, due to have evaluated nuclear data libraries implemented on the algorithm. In view of this, the aim of this work is determining the parameters evaluated in shielding materials, by using MCNPX code, who shows good agreement with experimental data from literature. Among the materials, Aluminium had lower emission and production of secondary particles
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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The increasing number of space debris in operating regions around the earth constitutes a real threat to space missions. The goal of the research is to establish appropriate scientific-technological conditions to prevent the destruction and/or impracticability of spacecraft in imminent collision in these regions. A definitive solution to this problem has not yet been reached with the degree of precision that the dynamics of spatial objects (vehicle and debris) requires mainly due to the fact that collisions occur in chains and fragmentation of these objects in the space environment. This fact threatens the space missions on time and with no prospects for a solution in the near future. We present an optimization process in finding the initial conditions (CIC) to collisions, considering the symmetry of the distributions of maximum relative positions between spatial objects with respect to the spherical angles. For this, we used the equations of the dynamics on the Clohessy-Witshire, representing a limit of validation that is highly computationally costly. We simulate different maximum relative positions values of the corresponding initial conditions given in terms of spherical angles. Our results showed that there are symmetries that significantly reduce operating costs, such that the search of the CIC is advantageously carried out up to 4 times the initial processing routine. Knowledge of CIC allows the propulsion system operating vehicle implement evasive maneuvers before impending collisions with space debris.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)