Inverse Problem
Mostrando 25-36 de 161 artigos, teses e dissertações.
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25. Implementação paralela do algoritmo iterativo de busca do parâmetro de regularização ótimo para o funcional de Tikhonov no problema de restauração de imagens / Parallel implementation of the iterative algorithm to search the optimal regularization parameter for the Tikhonov functional problem in image restoration
The use of techniques with the functional of Tikhonov in image processing has been widely used in recent years. The basic idea in this process is to modify an initial image using a convolution equation and to find a parameter which minimizes the function in order to obtain an aproximation of the original image. However, a typical problem in this method consi
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 27/04/2012
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26. Evaluation of radiances generated by solving the radiative-transfer equation with different approaches
Radiative transfer is the main phenomenon in the basis of several relevant problems of scientific and technological interest. Examples of application of the mathematical and computational modeling of such phenomenon can be found in astronomy, environmental sciences, engineering and medicine among many different areas. The integro-differential equation known
Journal of the Brazilian Society of Mechanical Sciences and Engineering. Publicado em: 2012-06
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27. A transformation of variables technique applicable to the boundary element method to simulate a special class of diffusive-advective potential problems
This paper describes a novel Boundary Element Technique developed for application to one-dimensional and a class of two-dimensional diffusive-advective potential problems. It is based on transformation of variable procedure to establish an integral equation inverse sentence, dealing only with boundary variables, using a fundamental solution associated with a
Journal of the Brazilian Society of Mechanical Sciences and Engineering. Publicado em: 2012-03
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28. The fundamental elements in certain inverse acoustic problems: their roles and interactions
Acoustic holography and holophony, wave field synthesis and active noise control are based on common elements which are causality, model, objective, and regularization. In the frequency domain (putting causality aside), a simple formulation states the influence - not the interaction - of errors of the model and objective and of regularization of the results.
J. Braz. Soc. Mech. Sci. & Eng.. Publicado em: 2012
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29. Uso de redes neurais recorrentes na determinação das constantes de acidez para a 7-epiclusianona em misturas etanol-água
This work propose a recursive neural network to solve inverse equilibrium problem. The acidity constants of 7-epiclusianone in ethanol-water binary mixtures were determined from multiwavelength spectrophotmetric data. A linear relationship between acidity constants and the %w/v of ethanol in the solvent mixture was observed. The proposed method efficiency is
Química Nova. Publicado em: 2012
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30. Neuro estimador para o fluxo de gases entre a superfície terrestre e a atmosfera / A neuro estimator for the flux of gases between the surface land and the atmosphere
Studies show that global warming may be irreversible in the medium or long term, and is a major cause of air pollution. However, this framework can be reversed or mitigated by estimating the amount of emissions, since the mapping of pollution sources could facilitate the work of public authorities in relation to environmental monitoring and the development o
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 21/11/2011
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31. Uma abordagem de compressão de imagens através de sistemas de funções iteradas
A new image compression technique is proposed, based on the affine transformations (ATs) that define an iterated function system (IFS). Previous related research in the field has shown that an image may be approximated by iteratively subjecting a set of sub-regions to a group of ATs. In this case, the original image should be partitioned in regions, and each
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 22/08/2011
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32. Uma abordagem de compressão de imagens através de sistemas de funções iteradas
Uma nova técnica para compressão de imagens é proposta, baseada em conjuntos de transformações afins (affine transformations - ATs), normalmente conhecidos como sistemas de funções iteradas (iterated function system - IFS). Pesquisas anteriores mostraram que uma imagem poderia ser aproximada pela aplicação de um grupo de ATs em conjuntos de sub-regi
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 22/08/2011
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33. Inclusão de MRI e informação multigrid a priori para inferência bayesiana de fontes de M/EEG / MRI image and multigrid a priori information for bayesian M/EEG source localization
Functional Neuroimaging has evolved in the last few decades with the introduction of techniques such as Positron Emission Tomography or PET and Functional Magnetic Ressonance Image or fMRI [Belliveau et al., 1991]. These allow observing brain activity with a resolution of a few millimeters and, due to the nature of the signal, a time resolution of the order
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 28/04/2011
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34. Estudo teórico da condução de calor e desenvolvimento de um sistema para a avaliação de fluidos de corte em usinagem / Theoretical study of heat conduction and development of a system for evaluation of cutting fluids in machining
Due to the rapid growth and development of machining processes there has been a demand for environmental sustainability and news cutting fluids have been applied. A reliable assessment of their efficiency in cooling the workpiece, tools and improving productivity is still a requirement. The present thesis presents a theoretical study and a proposal of a syst
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 30/03/2011
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35. Solution of porous media inverse drying problems using a combination of stochastic and deterministic methods
In the present work the inverse problem of simultaneous heat and mass transfer modeled by Luikov equations is studied using a hybrid combination of the Levenberg-Marquardt (LM), Simulated Annealing (SA) and Artificial Neural Network (ANN) methods. The direct and inverse problems are described, formulated and solved. After the use of an experiment design tech
Journal of the Brazilian Society of Mechanical Sciences and Engineering. Publicado em: 2011-12
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36. A validation metrics based model calibration applied on stranded cables
The present work is aimed at building a computational model for a typical stranded cable based on the basic principles of Verification and Validation. The model calibration and model tracking are guided based on a pool of validation metrics suitable for data which are commonly used in structural dynamics. The estimator used for the associated inverse problem
Journal of the Brazilian Society of Mechanical Sciences and Engineering. Publicado em: 2011-12