Inverse Problems
Mostrando 13-24 de 119 artigos, teses e dissertações.
-
13. Conjugate Gradient Method for the Solution of Inverse Problems: Application in Linear Seismic Tomography
RESUMO Consideramos o uso do método do gradientes conjugados para as equações normais na solução de problemas inversos decorrentes da tomografia sísmica. Empregamos um modelo linear de tomografia de tempos de trânsito, que é caracterizado por um sistema linear mal condicionado em que as incógnitas representam a vagarosidade em cada bloco do domínio
TEMA (São Carlos). Publicado em: 2015-12
-
14. An improved version of Inverse Distance Weighting metamodel assisted Harmony Search algorithm for truss design optimization
This paper focuses on a metamodel-based design optimization algorithm. The intention is to improve its computational cost and convergence rate. Metamodel-based optimization method introduced here, provides the necessary means to reduce the computational cost and convergence rate of the optimization through a surrogate. This algorithm is a combination of a hi
Lat. Am. j. solids struct.. Publicado em: 2013-03
-
15. Methane combustion kinetic rate constants determination: an ill-posed inverse problem analysis
Methane combustion was studied by the Westbrook and Dryer model. This well-established simplified mechanism is very useful in combustion science, for computational effort can be notably reduced. In the inversion procedure to be studied, rate constants are obtained from [CO] concentration data. However, when inherent experimental errors in chemical concentrat
Quím. Nova. Publicado em: 2013
-
16. 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
-
17. Problemas inversos aplicados à identificação de parâmetros hidrodinâmicos de um modelo do estuário do rio Macaé / Inverse problems applied to the identication of hydrodynamic parameters of a model of the Macae river estuary
Esta tese tem por objetivo propor uma estratégia de obtenção automática de parâmetros hidrodinâmicos e de transporte através da solução de problemas inversos. A obtenção dos parâmetros de um modelo físico representa um dos principais problemas em sua calibração, e isso se deve em grande parte à dificuldade na medição em campo desses parâme
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 27/02/2012
-
18. Simulações de problemas inversos com aplicações em engenharia nuclear usando técnicas de transporte de partículas neutras monoenergéticas na formulação unidimensional de ordenadas discretas / Simulations of inverse problems with applications one-speed neutral particle transport in slab-geometry discrete ordinates formulation.
Neste trabalho, três técnicas para resolver numericamente problemas inversos de transporte de partículas neutras a uma velocidade para aplicações em engenharia nuclear são desenvolvidas. É fato conhecido que problemas diretos estacionários e monoenergéticos de transporte são caracterizados por estimar o fluxo de partículas como uma função-distri
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 15/01/2012
-
19. 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
-
20. 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
-
21. A special class of continuous general linear methods
We consider the construction of a class of numerical methods based on the general matrix inverse [14] which provides continuous interpolant for dense approximations (output). Their stability properties are similar to those for Runge-Kutta methods. These methods provide a unifying scope for many families of traditional methods. They are self-starting, to chan
Comput. Appl. Math.. Publicado em: 2012
-
22. 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
-
23. 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
-
24. 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