The Singular Value Decomposition (SVD) has many applications in image processing. The SVD can be used to restore a corrupted image by separating significant information from the noise in the image data set. This thesis outlines broad applications that address current problems in digital image processing. In conjunction with SVD filtering, image compression using the SVD is discussed, including the process of reconstructing or estimating a rank reduced matrix representing the compressed image. Numerical plots and error measurement calculations are used to compare results of the two SVD image restoration techniques, as well as SVD image compression. The filtering methods assume that the images have been degraded by the application of a blurring function and the addition of noise. Finally, we present numerical experiments for the SVD restoration and compression to evaluate our computation.

Em experimentos de genótipos ambiente são comuns à presença de valores ausentes, devido à quantidade insuficiente de genótipos para aplicação dificultando, por exemplo, o processo de recomendação de genótipos mais produtivos, pois para a aplicação da maioria das técnicas estatísticas multivariadas exigem uma matriz de dados completa. Desta forma, aplicam-se métodos que estimam os valores ausentes a partir dos dados disponíveis conhecidos como imputação de dados (simples e múltiplas), levando em consideração o padrão e o mecanismo de dados ausentes. O objetivo deste trabalho é avaliar a eficiência da imputação múltipla livre da distribuição (IMLD) (BERGAMO et al., 2008; BERGAMO, 2007) comparando-a com o método de imputação múltipla com Monte Carlo via cadeia de Markov (IMMCMC), na imputação de unidades ausentes presentes em experimentos de interação genótipo (25) ambiente (7). Estes dados são provenientes de um experimento aleatorizado em blocos com a cultura de Eucaluptus grandis (LAVORANTI, 2003), os quais foram feitas retiradas de porcentagens aleatoriamente (10%, 20%, 30%) e posteriormente imputadas pelos métodos considerados. Os resultados obtidos por cada método mostraram que, a eficiência relativa em ambas as porcentagens manteve-se acima de 90%, sendo menor para o ambiente (4) quando imputado com a IMLD. Para a medida geral de exatidão, a medida que ocorreu acréscimo de dados em falta, foi maior ao imputar os valores ausentes com a IMMCMC, já para o método IMLD estes valores variaram sendo menor a 20% de retirada aleatória. Dentre os resultados encontrados, é de suma importância considerar o fato de que o método IMMCMC considera a suposição de normalidade, já o método IMLD leva vantagem sobre este ponto, pois não considera restrição alguma sobre a distribuição dos dados nem sobre os mecanismos e padrões de ausência. / In trials of genotypes by environment, the presence of absent values is common, due to the quantity of insufficiency of genotype application, making difficult for example, the process of recommendation of more productive genotypes, because for the application of the majority of the multivariate statistical techniques, a complete data matrix is required. Thus, methods that estimate the absent values from available data, known as imputation of data (simple and multiple) are applied, taking into consideration standards and mechanisms of absent data. The goal of this study is to evaluate the efficiency of multiple imputations free of distributions (IMLD) (BERGAMO et al., 2008; BERGAMO, 2007), compared with the Monte Carlo via Markov chain method of multiple imputation (IMMCMC), in the absent units present in trials of genotype interaction (25)environment (7). This data is provisional of random tests in blocks with Eucaluptus grandis cultures (LAVORANTI, 2003), of which random percentages of withdrawals (10%, 20%, 30%) were performed, with posterior imputation of the considered methods. The results obtained for each method show that, the relative efficiency in both percentages were maintained above 90%, being less for environmental (4) when imputed with an IMLD. The general measure of exactness, the measures where higher absent data occurred, was larger when absent values with an IMMCMC was imputed, as for the IMLD method, the varied absent values were lower at 20% for random withdrawals. Among results found, it is of sum importance to take into consideration the fact that the IMMCMC method considers it to be an assumption of normality, as for the IMLD method, it does not consider any restriction on the distribution of data, not on mechanisms and absent standards, which is an advantage on imputations.

Singular values have been found to be useful in the theory of unitarily invariant norms, as well as many modern computational algorithms. In examining singular value inequalities, it can be seen how these can be related to eigenvalues and how several algebraic inequalities can be preserved and written in an analogous singular value form. We examine the fundamental building blocks to the modern theory of singular value inequalities, such as positive matrices, matrix norms, block matrices, and singular value decomposition, then use these to examine new techniques being used to prove singular value inequalities, and also look at existing conjectures.

The purpose of this thesis is to implement algorithms of matrix eigendecomposition and pseudoinverse computation on a Field Programmable Gate Array (FPGA) platform. Firstly, there are described matrix decomposition methods that are broadly used in mentioned algorithms. Next section is focused on the basic theory and methods of computation eigenvalues and eigenvectors as well as matrix pseudoinverse. Several examples of implementation using Matlab are attached. The Vivado High-Level Synthesis tools and libraries were used for final implementation. After the brief introduction into the FPGA fundamentals the thesis continues with a description of implemented blocks. The results of each variant were compared in terms of timing and FPGA utilization. The selected block has been validated on the development board and its arithmetic precision was analyzed.

A practical procedure based on implicit time integration methods applied to the differential Lyapunov equations arising in the square root balanced truncation method is presented. The application of high order time integrators results in indefinite right-hand sides of the algebraic Lyapunov equations that have to be solved within every time step. Therefore, classical methods exploiting the inherent low-rank structure often observed for practical applications end up in complex data and arithmetic. Avoiding the additional effort treating complex quantities, a symmetric indefinite factorization of both the right-hand side and the solution of the differential Lyapunov equations is applied.:1 Introduction 2 Balanced truncation for LTV systems 3 Solving differential Lyapunov equations 4 Solving the reduced-order system 5 Numerical experiments 6 Conclusion

[pt] Motivado por problemas no campo da recuperação de sinais por programação convexa, o objetivo deste trabalho é fornecer uma análise precisa do método das bola pequena e suas conexões com a teoria não assintótica das matrizes aleatórias. Em particular, o estudo dos valores singulares cônicos de matrizes aleatórias desempenhará um papel fundamental na análise de tais problemas. / [en] Motivated by problems in the field of signal recovery by convex programming, the aim of this work is to provide a careful analysis of the celebrated small ball method and its connections with the non-asymptotic theory of random matrices. In particular, the study of the conic singular values of random matrices will play a key role to analyze such problems.

In this paper we deal with the `strength' of ill-posedness for ill-posed linear operator equations Ax = y in Hilbert spaces, where we distinguish according_to_M. Z. Nashed [15] the ill-posedness of type I if A is not compact, but we have R(A) 6= R(A) for the range R(A) of A; and the ill-posedness of type II for compact operators A: From our considerations it seems to follow that the problems with noncompact operators A are not in general `less' ill-posed than the problems with compact operators. We motivate this statement by comparing the approximation and stability behaviour of discrete least-squares solutions and the growth rate of Galerkin matrices in both cases. Ill-posedness measures for compact operators A as discussed in [10] are derived from the decay rate of the nonincreasing sequence of singular values of A. Since singular values do not exist for noncompact operators A; we introduce stability rates in order to have a common measure for the compact and noncompact cases. Properties of these rates are illustrated by means of convolution equations in the compact case and by means of equations with multiplication operators in the noncompact case. Moreover using increasing rearrangements of the multiplier functions specific measures of ill-posedness called ill-posedness rates are considered for the multiplication operators. In this context, the character of sufficient conditions providing convergence rates of Tikhonov regularization are compared for compact operators and multiplication operators.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-05-15T14:59:59Z No. of bitstreams: 1 marcoshenriquefonsecaribeiro.pdf: 12873424 bytes, checksum: 2b2b91fd2a9726856a0486afa760fe2c (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-05-17T16:01:12Z (GMT) No. of bitstreams: 1 marcoshenriquefonsecaribeiro.pdf: 12873424 bytes, checksum: 2b2b91fd2a9726856a0486afa760fe2c (MD5) / Made available in DSpace on 2017-05-17T16:01:12Z (GMT). No. of bitstreams: 1 marcoshenriquefonsecaribeiro.pdf: 12873424 bytes, checksum: 2b2b91fd2a9726856a0486afa760fe2c (MD5) Previous issue date: 2016-10-03 / A Tomografia por Impedância Elétrica (TIE) consiste em uma técnica onde imagens são construídas a partir da injeção de uma corrente elétrica em determinado meios, seguida da leitura de valores de potencial elétrico em pontos do contorno externo de tal domínio. Desta maneira, conhecendo-se ou estimando-se a condutividade elétrica de regiões internas ao meio, pode-se inferir aspectos geométricos da composição do mesmo. Trabalhos na literatura aplicam esta técnica ao contexto de obtenção de imagens do tórax humano, com objetivo de estimar a geometria das cavidades cardíacas de um determinado paciente. O objetivo final de estudo deste trabalho, dentro do contexto de aplicação da TIE à obtenção de cavidades cardíacas, é propor uma metodologia para a estimação da Fração de Ejeção Cardíaca, ou simplesmente Fração de Ejeção (FE), que consiste em medir o percentual de volume de sangue expulso dos ventrículos ao final de um ciclo de batimento do coração. Este trabalho visa evoluir outros trabalhos já existentes que modelam o problema acima descrito como sendo um problema inverso, de otimização, onde se pretende minimizar a diferença entre valores de potencial elétrico medidos e valores simulados por modelos computacionais. A evolução se dá em níveis diferentes. No primeiro nível, é feito um avanço sobre as técnicas de otimização para a resolução do problema inverso, em sua formulaçãobidimensional. Paratal, épropostaumametaheurísticaqueauxiliamétodosde buscanaobtençãodevaloresmaisacurados. Estametaheurísticaéapresentadaemversões sequencial e paralela. São apresentados resultados computacionais de testes realizados para este primeiro nível. Em um segundo nível, é feita a modelagem em três dimensões das mesmas abordagens já encontradas na literatura, que, para a aplicação específica da determinação da FE, até então estão limitadas a modelos bidimensionais. Assim, todo o problema é revisto para uma nova proposta de modelagem, que inclui a criação de modelos geométricos tridimensionais para as regiões de interesse do problema. Como principal contribuição do trabalho neste segundo nível, encontra-se um esquema de parametrização das malhas de polígonos que modelam ventrículos do coração, de forma que se tenha uma maneira compacta de representar as mesmas e, ao mesmo tempo, diminuindo o custo computacional do método de otimização por meio de drástica redução do número de variáveis do problema. Por fim, também é realizado um estudo preliminar da sensibilidade da técnica à presença de ruídos nos dados de entrada. / The Electrical Impedance Tomography (EIT) consists in a technique where images are constructed from the measurements of the electrical potential in some points on the external boundary of some specific domain, caused by the injection of an electrical current in such domain. This way, knowing or estimating the electrical conductivity of some regions inside the domain, geometric aspects of the composition of that domain can be inferred. Works in literature apply this technique to the context of obtaining images from the human thorax, with the objective of estimating the geometry of some cardiac cavities of a specific patient. The final goal of this work, inside the context of the obtention of cardiac cavities, is to propose a methodology for estimating the Cardiac Ejection Fraction, orsimplyEjectionFraction(EF),whichconsistsinmeasuringthepercentualofthevolume of blood expelled from the ventricles at the end of a heart beat cicle. This work intends to evolute previous works, that models the above mentioned problem as an inverse problem, an optimization problem, where the intention is to minimize the difference between the values of measured electrical potentials and the values obtained through simulation using computational models. This evolution occurs in different levels. In the first level, is performedanimprovementoverthepre-existentoptimizationtechniquesforthesolutionof theinverseproblem,inatwodimensionalversion. Forthis,isproposedametaheuristicthat assistssearchmethodstowardstheobtentionofmoreaccuratedvalues. Suchmetaheuristic is presented in sequential and parallel versions. Computational results for performed tests for this level are presented. In a second level, a three dimensional modeling of the same approaches found in literature is done. Those approaches, for the specific application of determining the EF, are so far limited to two dimensional models. Therefore, the whole problem is reviewed in order to propose a new model, which includes the creation of three dimensional geometric models for the regions of interest of the problem. As the main contribution of this work in that second level, there is a parameterization schema of the polygon meshes that model heart ventricles, so that it provides a compact way of representing such meshes, and, at the same time, a way of reducing the computational cost of the optimization method by means of a drastic reduction of the number of variables of the problem. Finally, a preliminary study of the sensibility of the technique to the presence of noise in the input data is also performed.

The electrical motors parameters identification is solved in this master’s thesis using subspace based methods. Electrical motors are simulated in Matlab/Simulink interactive environment, specifically permanent magnet DC motor and permanent magnet synchronous motor. Identification is developed in Matlab interactive environment. Different types of subspace algorithms are used for the estimation of parameters. Results of subspace parameters estimation are compared with least squares parameters estimation. The thesis describes subspace method, types of subspace algorithms, used electrical motors, nonlinear approach of identification and comparation of parameters identification.

In this paper we deal with the `strength' of ill-posedness for ill-posed linear operator equations Ax = y in Hilbert spaces, where we distinguish according_to_M. Z. Nashed [15] the ill-posedness of type I if A is not compact, but we have R(A) 6= R(A) for the range R(A) of A; and the ill-posedness of type II for compact operators A: From our considerations it seems to follow that the problems with noncompact operators A are not in general `less' ill-posed than the problems with compact operators. We motivate this statement by comparing the approximation and stability behaviour of discrete least-squares solutions and the growth rate of Galerkin matrices in both cases. Ill-posedness measures for compact operators A as discussed in [10] are derived from the decay rate of the nonincreasing sequence of singular values of A. Since singular values do not exist for noncompact operators A; we introduce stability rates in order to have a common measure for the compact and noncompact cases. Properties of these rates are illustrated by means of convolution equations in the compact case and by means of equations with multiplication operators in the noncompact case. Moreover using increasing rearrangements of the multiplier functions specific measures of ill-posedness called ill-posedness rates are considered for the multiplication operators. In this context, the character of sufficient conditions providing convergence rates of Tikhonov regularization are compared for compact operators and multiplication operators.