Sparsity Techniques
Mostrando 1-6 de 6 artigos, teses e dissertações.
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1. 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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2. Contribution of the LU factorization update in the Simplex method / Contribuição da atualização da decomposição LU no metodo Simplex
Finding efficient solution of linear systems is fundamental in the linear programming problems and the first method to obtain success for this class of problems was the Simplex method. With the objective to develop efficient alternatives to its implementation, techniques of the simplex basis LU factorization update are developed in this thesis to improve the
Publicado em: 2009
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3. Power system state estimation: computer program for analysis and updating of measurement set qualitative characteristics / Estimação de estado em sistemas elétricos de potência: programa para análise e atualização das características qualitativas de conjunto de medidas
To obtain a safe power system (PS) operation, becomes necessary a reliable state estimation (SE), since the real time control actions of a PS are based on the data obtained through the SE process. The first requirement for a successful SE process is the existence of a reliable measurement placement plan, that is, a measurement placement plan that guarantees
Publicado em: 2006
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4. Resolução do problema de fluxo de potência ótimo reativo via método da função lagrangiana barreira modificada / Resolution of reactive optimal power flow problem via method of Lagrangian modified barrier function
This work proposes an approach that uses an association of the methods of modified barrier and primal-dual interior points for the resolution of the reactive optimal power flow (OPF) problem. On this purpose, a bibliographical review was accomplished, which enlightened the optimization concepts applied to the static system of electrical energy and the method
Publicado em: 2006
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5. Simulação numerica para o calculo de campos eletricos em dominios ilimitados
A new mathematical treatment is proposed to the hybrid method of charge simulation and finite differences for the computation of unbounded electrostatic fields, also applicable to the similar hybrid method of charge simulation and finite elements. The charge simulation problem is solved by making use of the least squares technique, including the QR decomposi
Publicado em: 1993
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6. Search for IMRT inverse plans with piecewise constant fluence maps using compressed sensing techniques
An intensity-modulated radiation therapy (IMRT) field is composed of a series of segmented beams. It is practically important to reduce the number of segments while maintaining the conformality of the final dose distribution. In this article, the authors quantify the complexity of an IMRT fluence map by introducing the concept of sparsity of fluence maps and
American Association of Physicists in Medicine.