Sparsity
Mostrando 1-12 de 27 artigos, teses e dissertações.
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1. Charge sparsity: An index to quantify cation effects on clay dispersion in soils
ABSTRACT: Few approaches have been developed to measure the isolated effect of exchangeable cations on clay dispersion in soils. In this study, the charge sparsity (CS) index was proposed using the ratio between the cations hydrated ionic radius and valence. The index capacity to measure cation effects on clay dispersion in soils was also evaluated. Three Fe
Sci. agric. (Piracicaba, Braz.). Publicado em: 01/07/2019
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2. TRANSFER LEARNING FOR RESOLVING SPARSITY PROBLEM IN RECOMMENDER SYSTEMS: HUMAN VALUES APPROACH
ABSTRACT With the rapid rise in popularity of ecommerce application, Recommender Systems are being widely used by them to predict the response that a user will give to a given item. This prediction helps in cross selling, upselling and to increase the loyalty of their customers. However due to lack of sufficient feedback data these systems suffer from sparsi
JISTEM J.Inf.Syst. Technol. Manag.. Publicado em: 2017-12
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3. Representação esparsa e modelo de esparsidade conjunta no reconhecimento de faces / Sparse Representation and Joint Sparsity Model in Face Recognition
O trabalho desenvolvido nesta dissertação propõe a utilização do modelo de esparsidade conjunta com complemento de matrizes (JSM-MC) para composição da base de treino no contexto de reconhecimento de faces utilizando o classificador baseado em representação esparsa (SRC). O método proposto visa trabalhar com imagens de faces em diferentes condiçõ
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 11/07/2012
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4. Diferenciação automática de matrizes Hessianas / Automatic differentiation of hessian matrices
In the context of nonlinear programming, many algorithms boil down to the application of Newton s method to the system constituted by the first order Lagrangian conditions. The calculation of Hessian matrices is necessary in this class of solvers. Our focus is on the exact calculation, within machine precision, of Hessian matrices through automatic different
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 15/04/2011
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5. Eficiência de Compressive Sensing em modelo quadtree em imagens na presença de ruído
Esta pesquisa é do tipo quantitativa experimental e buscou investigar o quanto a eficiência do algoritmo CoSaMP modificado segundo a teoria de Compressive Sensing (CS) baseado em modelo QuadTree altera quando aplicado em imagens com ruído de quantização e esparsidade. O objetivo desta dissertação foi avaliar o impacto dos ruídos de quantização e de
Publicado em: 2010
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6. 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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7. Métodos de penalidade e barreira para programação convexa semidefinida / Penalty / barrier methods for convex semidefinite programming
This work deals with multiplier methods to solve semidefinite convex programming problems and the analysis of their proprieties based on the proximal point method applied on the dual problem. We focus on a subclass of semidefinite programming problems with affine constraints, for which we study duality relations an conditions for the existence of solutions o
Publicado em: 2009
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8. Tensorização de matrizes de rigidez para quadrados e hexaedros finitos de alta ordem / Tensorization of stiffness matrices for squares and hexaedral using high order FEM
High-order Finite Element Methods have been applied with success to problems of Fluid Dynamics and Electromagnetism. The main feature of these methods is to present an exponential convergence rate for problems with polinomial solution. However, due to the use of high-order interpolation functions, the elemental matrices are denser. This work shows a mathemat
Publicado em: 2009
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9. Método rápido para avaliação da margem de estabilidade de tensão devido a bifurcação de Hopf / Rapid method for evaluating the margin of voltage stability due to Hopf bifurcation
Despite the increasing development of Hopf bifurcations detection methods for electric power systems in the last decades, some aspects still require to progress, especially with the increasing necessity for higher safety in the electrical energy systems operation. One of these aspects concerns to the processing time of these methodologies to be used in real-
Publicado em: 2009
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10. 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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11. Saddle point systems with an application to the acceleration of the Augmented Lagrangian / Sistemas ponto de sela com uma aplicação a aceleração do Lagrangiano Aumentado
Saddle point systems arise in wide areas of research fields like physics, chemistry and engineering and images reconstructions, etc. Then, the properties of these systems and solving methods have been subjects of intense study in the last years. Depending upon the system properties, several methods were developed; some of these, exhibit the property of prese
Publicado em: 2008
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12. 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