Atributos topográficos e dados do Landsat7 no mapeamento digital de solos com uso de redes neurais

O objetivo deste trabalho foi avaliar variáveis discriminantes no mapeamento digital de solos com uso de redes neurais artificiais. Os atributos topográficos elevação, declividade, aspecto, plano de curvatura e índice topográfico, derivados de um modelo digital de elevação, e os índices de minerais de argila, óxido de ferro e vegetação por diferença normalizada, derivados de uma imagem do Landsat7, foram combinados e avaliados quanto à capacidade de discriminação dos solos de uma área no noroeste do Estado do Rio de Janeiro. Foram utilizados o simulador de redes neurais Java e o algoritmo de aprendizado "backpropagation". Os mapas gerados por cada um dos seis conjuntos de variáveis testados foram comparados com pontos de referência, para a determinação da exatidão das classificações. Esta comparação mostrou que o mapa produzido com a utilização de todas as variáveis obteve um desempenho superior (73,81% de concordância) ao de mapas produzidos pelos demais conjuntos de variáveis. Possíveis fontes de erro na utilização dessa abordagem estão relacionadas, principalmente, à grande heterogeneidade litológica da área, que dificultou o estabelecimento de um modelo de correlação ambiental mais realista. A abordagem utilizada pode contribuir para tornar o levantamento de solos no Brasil mais rápido e menos subjetivo.

Redes neurais artificiais para a modelagem do volume de madeira e biomassa do cerradão com dados de satélite

Resumo:O objetivo deste trabalho foi avaliar a eficácia da aplicação de modelos de análise de regressão e redes neurais artificiais (RNAs) na predição do volume de madeira e da biomassa acima do solo, da vegetação arbórea em área de cerradão. Volume de madeira e biomassa foram estimados com equações alométricas desenvolvidas para a área de estudo. Os índices de vegetação, como variáveis preditoras, foram estimados a partir de imagens do sensor LISS-III, e a área basal foi determinada por medições na floresta. A precisão das equações foi verificada pela correlação entre os valores estimados e observados (r), erro-padrão da estimativa (Syx) e gráfico residual. As equações de regressão para o volume de madeira total e do fuste (0,96 e 0,97 para r, e 11,92 e 9,72% para Syx, respectivamente) e para a biomassa (0,91 e 0,92 para r, e 22,73 e 16,80% para Syx, respectivamente) apresentaram bons ajustes. As redes neurais também apresentaram bom ajuste com o volume de madeira (0,99 e 0,99 para r, e 4,93 e 4,83% para Syx) e a biomassa (0,97 e 0,98 r, e 8,92 e 7,96% para Syx, respectivamente). A área basal e os índices de vegetação foram eficazes na estimativa do volume de madeira e biomassa para o cerradão. Os valores reais de volume de madeira e biomassa não diferiram estatisticamente dos valores estimados pelos modelos de regressão e redes neurais (χ2ns); contudo, as RNAs são mais acuradas.

Redes neurais artificiais para identificar genótipos de feijão-caupi semiprostrado com alta adaptabilidade e estabilidade fenotípicas

Resumo: O objetivo deste trabalho foi verificar a concordância entre as redes neurais artificiais (RNAs) e o método de Eberhart & Russel na identificação de genótipos de feijão-caupi (Vigna unguiculata) com alta adaptabilidade e estabilidade fenotípicas. Utilizou-se o delineamento experimental de blocos ao acaso com quatro repetições. Os tratamentos consistiram de 18 linhagens experimentais e duas cultivares de feijão-caupi. Foram conduzidos quatro ensaios de valor de cultivo e uso nos municípios de Aquidauana, Chapadão do Sul e Dourados, no estado do Mato Grosso do Sul. Os dados de produtividade de grãos foram submetidos às análises de variância individual e conjunta. Em seguida, os dados foram submetidos às análises de adaptabilidade e estabilidade por meio dos métodos de Eberhart & Russell e de RNAs. Houve elevada concordância entre os métodos avaliados quanto à discriminação da adaptabilidade fenotípica dos genótipos de feijão-caupi semiprostrado, o que indica que as RNAs podem ser utilizadas em programas de melhoramento genético. Em ambos os métodos avaliados, os genótipos BRS Xiquexique, TE97-304G-12 e MNC99-542F-5 são recomendados para ambientes desfavoráveis, gerais e favoráveis, respectivamente, por apresentarem produtividade de grãos acima da média geral dos ambientes e alta estabilidade fenotípica.

A inovação tecnológica e o avanço científico: a química em perspectiva

Some general features about the role of Science and Technology in the modern western civilizations are discussed, emphasizing those related to Chemistry. The discussion is centered on the social regulation of technological and scientific institutions and on the way this regulation takes place in response to social demands. Finally, some new trends are presented about the Brazilian chemistry courses and how the local educational authorities intend to modernize them.

Redes neurais e suas aplicações em calibração multivariada

Neural Networks are a set of mathematical methods and computer programs designed to simulate the information process and the knowledge acquisition of the human brain. In last years its application in chemistry is increasing significantly, due the special characteristics for model complex systems. The basic principles of two types of neural networks, the multi-layer perceptrons and radial basis functions, are introduced, as well as, a pruning approach to architecture optimization. Two analytical applications based on near infrared spectroscopy are presented, the first one for determination of nitrogen content in wheat leaves using multi-layer perceptrons networks and second one for determination of BRIX in sugar cane juices using radial basis functions networks.

Estudo do estado fundamental de aglomerados de silício via redes neurais

We introduce a global optimization method based on the cooperation between an Artificial Neural Net (ANN) and Genetic Algorithm (GA). We have used ANN to select the initial population for the GA. We have tested the new method to predict the ground-state geometry of silicon clusters. We have described the clusters as a piling of plane structures. We have trained three ANN architectures and compared their results with those of pure GA. ANN strongly reduces the total computational time. For Si10, it gained a factor of 5 in search speed. This method can be easily extended to other optimization problems.

A questão da inovação em fármacos no Brasil: proposta de criação do programa nacional de fármacos (Pronfar)

Medicines are essential instruments to the preservation, maintenance and promotion of Health. The access to the medicine represents an important factor of social inclusion, depending on the availability of the pharmaceutical - active principle contained in the medicine that in 85% of the cases has a synthetic origin. In this scenario the importance of knowing how to make pharmaceuticals and medicines plays a significant role for the viability of the autonomous Health politics necessary for the demands of the major Nations. In this context, this work describes concisely the main aspects involved in the interdisciplinary drug discovery process, identifying the possible gorges for the successful development of innovative drugs in Brazil.

Aspectos e fatores da produtividade em pesquisa, desenvolvimento e inovação

Comparison of national budgets for R&D is often made but it should consider the relative productivity and their factors. In Brazil, inefficiency factors as well as their causes have been diagnosed since the late 60's and solutions have been proposed within various governmental organisms, from CNPq to the strategy think tanks. Problems that hinder R&D and innovation in Brazil are reviewed from a historical perspective together with the proposed solutions providing a detailed analysis of the difficulties that have to be overcome to achieve a more effective innovation environment, adequate for the present times, challenges and opportunities.

Inovação tecnológica e produção no setor químico

Innovation is the main tool for competitiveness and growth in the chemical sector and the main factors for innovation activities in industry as well as the innovation dynamics are discussed in this paper. Success indicators of innovation in Oxiteno are the following: 54% of the current production derives from RD&E projects, 11% of the gross margin in the internal market is due to new products, the company is a technology licensor, holding 17 patents and keeping a strong participation in the production and service sales in the high technology catalysts area, beyond its core petrochemicals and surfactants area.

O Quadrante de Ruetsap e a anti-ciência, tecnologia e inovação

The concept of research and the controversy among classical models for C, T & I, outdated by the development of knowledge and Post-modern society needs were revisited through the (3) Quadrants advanced by Donald Stokes in the mid-nineties. The scientific community to fit into these Quadrants was faced with many difficulties and reacted by issuing pseudo-facts, accepted by under-prepared technocrats as viable justifications for conducting research in face of these new paradigms. In a poor country full of contrast and needs such as Brazil, this attitude satisfies the bureaucracy and academic elite, but frustrates government and society, that do not get, in the expected measure, the benefits of their commitment with the Teaching, Research and Extension Sectors mainly embedded in the Public University system. An extension, in fact a contradictory approach, to Pasteur's Quadrant, is proposed to characterize this situation: The Syndrome of Ruetsap's Quadrant.

A importância do observatório de atividades industriais vis-à-vis tendências em ciência, tecnologia e inovação

Given that innovation is fundamental for competitiveness, and that it is intrinsically linked to knowledge, it has become essential to foster effective interaction between the Brazilian productive sector and universities and R&D centers. This interface should be created by means of the model used in developed countries: Observatory of Industrial Activities and Trends in Science, Technology and Innovation. The present work describes its main functions, using examples of activities undertaken by the Chemical Industry Information System of the Federal University of Rio de Janeiro related to production systems of primary and high-tech industries, examining the diffusion of knowledge to decision-makers.

Desempenho físico-químico de metais e estruturas de concreto de redes de distribuição de energia: estudo de caso na região de Manaus

The influence of natural aging furthered by atmospheric corrosion of parts of electric transformers and materials, as well as of concrete poles and cross arms containing corrosion inhibitors was evaluated in Manaus. Results for painted materials, it could showed that loss of specular gloss was more intensive in aliphatic polyurethane points than in acrylic polyurethane ones. No corrosion was observed for metal and concrete samples until 400 days of natural aging. Corrosion in steel reinforcement was noticed in some poles, arising from manufacturing faults, such as low cement content, water/cement ratio, thin concrete cover thickness, etc. The performance of corrosion inhibitors was assessed by many techniques after natural and accelerated aging in a 3.5% saline aqueous solution. The results show the need for better chemical component selection and its concentration in the concrete mixture.

A tabela periódica dos elementos químicos prevista por redes neurais artificiais de Kohonen

Although several chemical elements were not known by end of the 18th century, Mendeleyev came up with an astonishing achievement: the periodic table of elements. He was not only able to predict the existence of (then) new elements but also to provide accurate estimates of their chemical and physical properties. This is certainly a relevant example of the human intelligence. Here, we intend to shed some light on the following question: Can an artificial intelligence system yield a classification of the elements that resembles, in some sense, the periodic table? To achieve our goal, we have fed a self-organized map (SOM) with information available at Mendeleyev's time. Our results show that similar elements tend to form individual clusters. Thus, SOM generates clusters of halogens, alkaline metals and transition metals that show a similarity with the periodic table of elements.