Inverse Problems
Mostrando 37-48 de 119 artigos, teses e dissertações.
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37. The generalized attenuated Radon tranform : analytic inversion, approximations, iterative methods and applications on fluorescence tomography / A transformada generalizada atenuada de Radon : inversão, analitica, aproximações, metodos iterativos e aplicações em tomografia por fluorescencia
A Tomografia por Fluorescência de Raios X é uma nova técnica que combina a tomografia por transmissão de Raios X e a tomografia por emissão. Uma amostra de tecido (ou corpo) é bombardeada por Raios X de alta intensidade (gerados por um síncrotron) e, metais ou outros elementos a serem estudados, emitem fluorescência para uma faixa de energia típica
Publicado em: 2010
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38. Structural damage identification via accoustic wave propagation approach using computational intelligence techniques / Identificação de dano estrutural via abordagem de propagação de ondas acústicas utilizando técnicas de inteligência computacional
No presente trabalho, um algoritmo algébrico sequencial é utilizado para descrever a propagação de ondas acústicas ao longo de uma barra e utilizado na identificação de danos. Esse algoritmo é validado com base nos conficientes de sensibilidade dos ecos correspondentes aos diferentes cenários de danos apresentados. Na formulação do problema de ide
Publicado em: 2010
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39. Prevalência de anemia e fatores de risco associados, em crianças de 06 a 24 meses no município do Guarujá / Prevalence of anemia and correlated risk factors in 06 to 24 months old children in the municipality of Guarujá
Anemia due to iron deficiency in children is one of the greatest nutrition problems challenging developing countries. Young children with less than two years of age are the greatest risk group. Main causes are iron depletion at birth and the increase in iron demand due to the accelerated growth of children in this period. Objectives are to verify the prevale
Publicado em: 2010
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40. Combinação de modelos de campos aleatórios markovianos para classificação contextual de imagens multiespectrais / Combining markov random field models for multispectral image contextual classification
This work presents a novel MAP-MRF approach for multispectral image contextual classification by combining higher-order Markov Random Field models. The statistical modeling follows the Bayesian paradigm, with the definition of a multispectral Gaussian Markov Random Field model for the observations and a Potts MRF model to represent the a priori knowledge. In
Publicado em: 2010
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41. Estudos de processos térmicos decorrentes da usinagem: aplicação de problemas inversos em furação / Thermal studies of cutting process. Inverse problem application in drilling
Heat generation is a common problem during any type of cutting, but particularly during a drilling due to the difficulty of conducting heat away from the cutting edge and the fact that the chips remain in contact with the tool for a relatively long time in a hole. Cutting temperatures have strongly influenced both the tool life and the metallurgical state of
Publicado em: 2009
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42. Inverse problems evaluation of dispersive mechanisms / Avaliação de mecanismos dispersivos em rios através de problemas inversos
Nesta dissertação é apresentada a avaliação da dispersão de contaminantes no Rio São Pedro, pequeno curso situado na Bacia Hidrográfica do Rio Macaé, centro-norte do Estado do Rio de Janeiro. Para tanto, utilizou-se uma abordagem que conjugou simulação e observação. A simulação compreendeu a modelagem do transporte de substância conservativa
Publicado em: 2009
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43. Técnicas computacionais para a implementação eficiente e estável de métodos tipo simplex / Computational techniques for an efficient and stable implemantation of simplex-type methods
Simplex-type methods are the basis of the main linear optimization solvers. The straightforward implementation of these methods as they are presented in theory yield unexpected results in solving reallife large-scale problems. Hence, it is essencial to use suitable computational techniques for an efficient and stable implementation. In this thesis, we addres
Publicado em: 2009
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44. Problemas de estruturas aditivas e multiplicativas propostos em livros didÃticos de matemÃtica: o impacto do Programa Nacional do Livro DidÃtico
This research presents an analysis of how additive and multiplicative problems are presented in Elementary School Mathematics textbooks. The aim of the study is to observe the impact that the PNLD, the Brazilian National Plan of Textbooks, has on the treatment given to the meanings of the arithmetic operations and the forms of symbolic representations presen
Publicado em: 2009
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45. Characterization of skin-pass mill over-rolling on a IF steel. / Caracterização de um aço IF após relaminação no laminador de encruamento.
The continuous search of the improvement of the competitiveness of the steel front to the succedanea has led to the development of special materials, allowing to take care of three of the main demands of the automotive sector: reduction of weight, fuel economy and increase of the safety of the user. The conditions under which the process of strain hardening
Publicado em: 2009
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46. Optimum design applied to electrooptic modulators / Projeto ótimo de moduladores eletroópticos
Many design developments involve the optimization of several objective functions. These objective functions are often conflicting with each other and they cannot be simply aggregated into only one function to be optimized. This type of problem is known as the multiobjective optimization problem, for which the solution is a set of points known as Pareto optim
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 08/02/2008
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47. Slow-release fluoride devices: a literature review
Although the prevalence of caries has decreased dramatically over the past decades, it has become a polarised disease, with most of subjects presenting low caries levels and few individuals accounting for most of the caries affected surfaces. Thus it become evident for the need of clinical approaches directed at these high-risk patients, in order to overcome
Journal of Applied Oral Science. Publicado em: 2008-08
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48. Problemas inversos sobre a esfera / Inverse problems of the sphere
The objective of this thesis is the development of algorithms to determine the solutions, and for determination of sources of, the equations of Poisson and heat conduction for a sphere. We establish the form of equations of Poisson and heat on the sphere, and developed iterative methods, based on a icosaedral mesh and its dual mesh, to obtain the solutions f
Publicado em: 2008