Conjugate Gradient
Mostrando 1-12 de 39 artigos, teses e dissertações.
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1. Ultra Wide Band Radar Cross Section Reduction of a Perfectly Electric Conductor Sphere by the Application of Multilayer Metamaterial Coatings
Abstract A full-wave analytical method using the addition theorems and Hertzian potential functions are used to compute the radar cross section of a sphere coated by several layers composed of common materials and metamaterials. The minimization and maximization of radar cross section of a perfectly electric conductor sphere with such coatings are realized i
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2016-12
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2. 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
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3. Uma nova abordagem para resolução de problemas de fluxo de carga com variáveis discretas / A new approach for solving load flow problems with discrete variables
Este trabalho apresenta uma nova abordagem para a modelagem e resolução de problemas de fluxo de carga em sistemas elétricos de potência. O modelo proposto é formado simultaneamente pelo conjunto de equações não lineares que representam as restrições de carga do problema e por restrições de complementaridade associadas com as restrições de oper
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 07/05/2012
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4. ANN model of RF MEMS Lateral SPDT switches for millimeter wave applications
This paper presents Artificial Neural Network (ANN) implementation for the Radio Frequency (RF) and Mechanical modeling of lateral RF Micro Electro Mechanical System (MEMS) series micro machined Single pole double through (SPDT) switch. We propose an efficient approach based on ANN for analyzing the losses in ON and OFF state of lateral RF MEMS series switch
Journal of Microwaves, Optoelectronics and Electromagnetic Applications. Publicado em: 2012-06
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5. The global convergence of a descent PRP conjugate gradient method
Recently, Yu and Guan proposed a modified PRP method (called DPRP method) which can generate sufficient descent directions for the objective function. They established the global convergence of the DPRP method based on the assumption that stepsize is bounded away from zero. In this paper, without the requirement of the positive lower bound of the stepsize, w
Computational & Applied Mathematics. Publicado em: 2012
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6. Heuristics for implementation of a hybrid preconditioner for interior-point methods
This article presents improvements to the hybrid preconditioner previously developed for the solution through the conjugate gradient method of the linear systems which arise from interior-point methods. The hybrid preconditioner consists of combining two preconditioners: controlled Cholesky factorization and the splitting preconditioner used in different pha
Pesquisa Operacional. Publicado em: 2011-12
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7. Using truncated conjugate gradient method in trust-region method with two subproblems and backtracking line search
A trust-region method with two subproblems and backtracking line search for solving unconstrained optimization is proposed. At every iteration, we use the truncated conjugate gradient method or its variation to solve one of the two subproblems approximately. Backtracking line search is carried out when the trust-region trail step fails. We show that this met
Computational & Applied Mathematics. Publicado em: 2010-06
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8. Estudo de alguns metodos determinsticos de otimização irrestrita / Study of some deterministic methods for unconstrained optimization
In this work some classical methods of linear search for unconstrained optimization are studied. The main mathematical formulations for the optimization problem are presented. Two strategies, linear search and trust region, for the algorithm to move from one iteration to another are discussed. Furthermore, the main considerations about the choice of step len
Publicado em: 2010
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9. Resolução de um problema térmico inverso utilizando processamento paralelo em arquiteturas de memória compartilhada / Resolution of an inverse thermal problem using parallel processing on shared memory architectures
A programação paralela tem sido freqüentemente adotada para o desenvolvimento de aplicações que demandam alto desempenho computacional. Com o advento das arquiteturas multi-cores e a existência de diversos níveis de paralelismo é importante definir estratégias de programação paralela que tirem proveito desse poder de processamento nessas arquitetu
Publicado em: 2010
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10. Modelling evapotranspiration for reference crop and acid lime orchard based on regression and artificial neural network tecniques / Modelagem da evapotranspiração de referência e da evapotranspiração de limeira ácida com aplicação de técnicas de regressão e redes neurais artificiais
The main objective of this study was to test artificial neural networks (ANNs) of multilayer perceptron type (MLP) for estimating reference evapotranspiration, diffusive leaf conductance and crop evapotranspiration of a mature and irrigated citrus orchard. The ANNs were trained under conjugate gradient algorithm. The sigmoid and linear activation functions w
Publicado em: 2010
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11. A new approach for estimation of PVT properties of pure gases based on artificial neural network model
Equations of state are useful for description of fluid properties such as pressure-volume-temperature (PVT). However, the success estimation of such correlations depends mainly on the range of data which have originated. Therefore new models are highly required. In this work a new method is proposed based on Artificial Neural Network (ANN) for estimation of
Brazilian Journal of Chemical Engineering. Publicado em: 2009-03
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12. New versions of the Hestenes-Stiefel nonlinear conjugate gradient method based on the secant condition for optimization
Based on the secant condition often satisfied by quasi-Newton methods, two new versions of the Hestenes-Stiefel (HS) nonlinear conjugate gradient method are proposed, which are descent methods even with inexact line searches. The search directions of the proposed methods have the form d k = - θkg k + βkHSd k-1, or d k = -g k + βkHSd k-1+ θky k-1. When ex
Computational & Applied Mathematics. Publicado em: 2009