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Direct and Line Based Iterative Methods for Solving Sparse Block Linear SystemsYang, Xiaolin January 2018 (has links)
No description available.
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Analysis and Design of Steel Deck-Concrete Composite SlabsWidjaja, Budi R. 29 October 1997 (has links)
As cold-formed steel decks are used in virtually every steel-framed structure for composite slab systems, efforts to develop more efficient composite floor systems continues. Efficient composite floor systems can be obtained by optimally utilizing the materials, which includes the possibility of developing long span composite slab systems. For this purpose, new deck profiles that can have a longer span and better interaction with the concrete slab are investigated.
Two new mechanical based methods for predicting composite slab strength and behavior are introduced. They are referred to as the iterative and direct methods. These methods, which accurately account for the contribution of parameters affecting the composite action, are used to predict the strength and behavior of composite slabs. Application of the methods in the analytical and experimental study of strength and behavior of composite slabs in general reveals that more accurate predictions are obtained by these methods compared to those of a modified version of the Steel Deck Institute method (SDI-M). A nonlinear finite element model is also developed to provide additional reference. These methods, which are supported by elemental tests of shear bond and end anchorages, offer an alternative solution to performing a large number of full-scale tests as required for the traditional m-k method. Results from 27 composite slab tests are compared with the analytical methods.
Four long span composite slab specimens of 20 ft span length, using two different types of deck profiles, were built and tested experimentally. Without significantly increasing the slab depth and weight compared to those of composite slabs with typical span, it was found that these long span slabs showed good performance under the load tests. Some problems with the vibration behavior were encountered, which are thought to be due to the relatively thin layer of concrete cover above the deck rib. Further study on the use of deeper concrete cover to improve the vibrational behavior is suggested.
Finally, resistance factors based on the AISI-LRFD approach were established. The resistance factors for flexural design of composite slab systems were found to be f=0.90 for the SDI-M method and f=0.85 for the direct method. / Ph. D.
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Sequential/parallel reusability study on solving Hamilton-Jacobi-Bellman equations / Etude de la réutilisabilité séquentielle/parallèle pour la résolution des équations Hamilton-Jacobi-BellmanDang, Florian 22 July 2015 (has links)
La simulation numérique est indissociable du calcul haute performance. Ces vingt dernières années,l'informatique a connu l'émergence d'architectures parallèles multi-niveaux. Exploiter efficacement lapuissance de calcul de ces machines peut s'avérer être une tâche délicate et requérir une expertise à la foistechnologique sur des notions avancées de parallélisme ainsi que scientifique de part la nature même desproblèmes traités.Le travail de cette thèse est pluri-disciplinaire s'appuyant sur la conception d'une librairie de calculparallèle réutilisable pour la résolution des équations Hamilton-Jacobi-Bellman. Ces équations peuventse retrouver dans des domaines diverses et variés tels qu'en biomédical, géophysique, ou encore robotiqueen l'occurence sur les applications de planification de mouvement et de reconstruction de formestri-dimensionnelles à partir d'images bi-dimensionnelles. Nous montrons que les principaux algorithmesnumériques amenant a résoudre ces équations telles que les méthodes de type fast marching, ne sont pasappropriés pour être efficaces dans un contexte parallèle. Nous proposons la méthode buffered fast iterativequi permet d'obtenir une scalabilité parallèle non obtenue jusqu'alors. Un des points sensibles relevésdans cette thèse est de parvenir à trouver une recette de compromis entre abstraction, performance etmaintenabilité afin de garantir non seulement une réutilisabilitédans le sens classique du domaine de génielogiciel mais également en terme de réutilisabilité séquentielle/parallèle / Numerical simulation is strongly bound with high performance computing. Programming scientificsoftwares requires at the same time good knowledge on the mathematical numerical models and alsoon the techniques to make them efficient on today's computers. Indeed, these last twenty years, wehave experienced the rising of multi-level parallel architectures. The work in this thesis dissertation ismultidisciplinary by designing a reusable parallel numerical library for solving Hamilton-Jacobi-Bellmanequations. Such equations are involved in various fields such as in biomedical, geophysics or robotics. Inparticular, we will show interests in path planning and shape from shading applications. We show thatthe methods to solve these equations such as the widely used fast marching method, are not designedto be used effciently in a parallel context. We propose a buffered fast iterative method which givesan interesting parallel scalability. This dissertation takes interest in the challenge to find compromisesbetween abstraction, performance and maintainability in order to combine both software reusability andalso sequential/parallel reusability. We propose code abstraction allowing algorithmic and data genericitywhile trying to keep a maintainable and performant code potentially parallelizable
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Ustálený chod a zkratové poměry v síti 110 kV E.ON napájené z rozvodny 110 kV Otrokovice v roce 2011 / Stabilized operation and short - circuit conditions within E.ON 110 kV power network supplied from Otrokovice 110kV switching station, during the period of 2011Jurča, Ondřej January 2011 (has links)
Distribution network 110 kV owned by E. ON in the area Otrokovice; powered by 110 kV and two variants of involvement contained.The first option is basic involvement, without the use of the bridge. The second option includes involvement with the bridge. The aim of this study is to compare; by calculating the steady-state network operation and short circuit conditions of the network, the involvement of these two options. The thesis is divided into two parts, theoretical and practical. The theoretical part consists of a description of the steady operation of networks of high-voltage and short circuit ratio calculations. Load flow calculations are described by the Gauss-Seidel and Newton iterative method. In the case of short-circuit conditions, the effects of their characteristic values, processes and various methods of calculation are described.In the second part, this theoretical knowledge is applied to input data and dispatching programme with the appropriate calculations of network operation and short circuit conditions. The calculated values are listed in the thesis, on the basis of which an evaluation of the two possible connections is made.
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Numerical methods for solving linear ill-posed problemsIndratno, Sapto Wahyu January 1900 (has links)
Doctor of Philosophy / Department of Mathematics / Alexander G. Ramm / A new method, the Dynamical Systems Method (DSM), justified
recently, is applied to solving ill-conditioned linear algebraic
system (ICLAS). The DSM gives a new approach to solving a wide class
of ill-posed problems. In Chapter 1 a new iterative scheme for
solving ICLAS is proposed. This iterative scheme is based on the DSM
solution. An a posteriori stopping rules for the proposed method is
justified. We also gives an a posteriori stopping rule for a
modified iterative scheme developed in A.G.Ramm, JMAA,330
(2007),1338-1346, and proves convergence of the solution obtained by
the iterative scheme. In Chapter 2 we give a convergence analysis of
the following iterative scheme:
u[subscript]n[superscript]delta=q u[subscript](n-1)[superscript]delta+(1-q)T[subscript](a[subscript]n)[superscript](-1) K[superscript]*f[subscript]delta, u[subscript]0[superscript]delta=0,
where T:=K[superscript]* K, T[subscript]a :=T+aI, q in the interval (0,1),\quad
a[subscript]n := alpha[subscript]0 q[superscript]n, alpha_0>0, with finite-dimensional
approximations of T and K[superscript]* for solving stably Fredholm integral
equations of the first kind with noisy data. In Chapter 3 a new
method for inverting the Laplace transform from the real axis is
formulated. This method is based on a quadrature formula. We assume
that the unknown function f(t) is continuous with (known) compact
support. An adaptive iterative method and an adaptive stopping rule,
which yield the convergence of the approximate solution to f(t),
are proposed in this chapter.
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Iterative Methods for Minimization Problems over Fixed Point SetsChen, Yen-Ling 02 June 2011 (has links)
In this paper we study through iterative methods the minimization problem
min_{x∈C} £K(x) (P)
where the set C of constraints is the set of fixed points of a nonexpansive mapping T in a real Hilbert space H, and the objective function £K:H¡÷R is supposed to be continuously Gateaux dierentiable. The gradient projection method for solving problem (P) involves with the projection P_{C}. When C = Fix(T), we provide a
so-called hybrid iterative method for solving (P) and the method involves with the mapping T only. Two special cases are included: (1) £K(x)=(1/2)||x-u||^2 and (2) £K(x)=<Ax,x> - <x,b>. The first case corresponds to finding a fixed point of T which is closest to u from the fixed point set Fix(T). Both cases have received a lot of investigations recently.
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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 restorationClaudir Oliveira 27 April 2012 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O uso de técnicas com o funcional de Tikhonov em processamento de imagens tem sido
amplamente usado nos últimos anos. A ideia básica nesse processo é modificar uma imagem inicial
via equação de convolução e encontrar um parâmetro que minimize esse funcional afim de
obter uma aproximação da imagem original. Porém, um problema típico neste método consiste
na seleção do parâmetro de regularização adequado para o compromisso entre a acurácia e a estabilidade
da solução. Um método desenvolvido por pesquisadores do IPRJ e UFRJ, atuantes na
área de problemas inversos, consiste em minimizar um funcional de resíduos através do parâmetro
de regularização de Tikhonov. Uma estratégia que emprega a busca iterativa deste parâmetro
visando obter um valor mínimo para o funcional na iteração seguinte foi adotada recentemente
em um algoritmo serial de restauração. Porém, o custo computacional é um fator problema encontrado
ao empregar o método iterativo de busca. Com esta abordagem, neste trabalho é feita
uma implementação em linguagem C++ que emprega técnicas de computação paralela usando
MPI (Message Passing Interface) para a estratégia de minimização do funcional com o método
de busca iterativa, reduzindo assim, o tempo de execução requerido pelo algoritmo. Uma versão
modificada do método de Jacobi é considerada em duas versões do algoritmo, uma serial e outra
em paralelo. Este algoritmo é adequado para implementação paralela por não possuir dependências
de dados como de Gauss-Seidel que também é mostrado a convergir. Como indicador
de desempenho para avaliação do algoritmo de restauração, além das medidas tradicionais, uma
nova métrica que se baseia em critérios subjetivos denominada IWMSE (Information Weighted
Mean Square Error) é empregada. Essas métricas foram introduzidas no programa serial de
processamento de imagens e permitem fazer a análise da restauração a cada passo de iteração.
Os resultados obtidos através das duas versões possibilitou verificar a aceleração e a eficiência
da implementação paralela. A método de paralelismo apresentou resultados satisfatórios em um
menor tempo de processamento e com desempenho aceitável. / 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 consists in
the choice of the regularization parameter in the appropriate compromise between accuracy and
stability of the solution. A method developed by researchers of IPRJ and UFRJ, operating in the
area of inverse problems, consists on minimizing a functional of residues through a functional
parameter Tikhonovs regularization. A strategy that uses the iterative search of this parameter
aiming at to get a minimum value for the functional in the following iteration was adopted recently
in a serial algorithm of restoration. However, the computational cost is a factor problem
found when using the iterative search. With this approach, an implementation in C++ language
was made using techniques of parallel computation using MPI (Message Passing Interface) for
the in the choice of the regularization parameter in the appropriate compromise between accuracy
and stability of the soluton with the method of iterative search, thus reducing, the time of
execution required for the algorithm. A modified version of the Jacobi method is considered
to be two versions of the algorithm, one serial and one parallel. This algorithm is adequate for
parallel implementation because it has no data dependencies such as the Gauss-Seidel method
is also shown to converge. As indicating of performance for evaluation of the restoration algorithm,
in addition to the traditional measures, new metric that is based on subjective criteria
called IWMSE (InformationWeighted Mean Square Error) is used. These metrics were introduced
in the program of image processing and allow to make the analysis of the restoration to each
step of iteration. The results obtained using the two possible versions verify the efficiency of
acceleration and the parallel implementation. The method of parallelism achieved satisfactory
results in a shorter processing time and with acceptable performance.
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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 restorationClaudir Oliveira 27 April 2012 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O uso de técnicas com o funcional de Tikhonov em processamento de imagens tem sido
amplamente usado nos últimos anos. A ideia básica nesse processo é modificar uma imagem inicial
via equação de convolução e encontrar um parâmetro que minimize esse funcional afim de
obter uma aproximação da imagem original. Porém, um problema típico neste método consiste
na seleção do parâmetro de regularização adequado para o compromisso entre a acurácia e a estabilidade
da solução. Um método desenvolvido por pesquisadores do IPRJ e UFRJ, atuantes na
área de problemas inversos, consiste em minimizar um funcional de resíduos através do parâmetro
de regularização de Tikhonov. Uma estratégia que emprega a busca iterativa deste parâmetro
visando obter um valor mínimo para o funcional na iteração seguinte foi adotada recentemente
em um algoritmo serial de restauração. Porém, o custo computacional é um fator problema encontrado
ao empregar o método iterativo de busca. Com esta abordagem, neste trabalho é feita
uma implementação em linguagem C++ que emprega técnicas de computação paralela usando
MPI (Message Passing Interface) para a estratégia de minimização do funcional com o método
de busca iterativa, reduzindo assim, o tempo de execução requerido pelo algoritmo. Uma versão
modificada do método de Jacobi é considerada em duas versões do algoritmo, uma serial e outra
em paralelo. Este algoritmo é adequado para implementação paralela por não possuir dependências
de dados como de Gauss-Seidel que também é mostrado a convergir. Como indicador
de desempenho para avaliação do algoritmo de restauração, além das medidas tradicionais, uma
nova métrica que se baseia em critérios subjetivos denominada IWMSE (Information Weighted
Mean Square Error) é empregada. Essas métricas foram introduzidas no programa serial de
processamento de imagens e permitem fazer a análise da restauração a cada passo de iteração.
Os resultados obtidos através das duas versões possibilitou verificar a aceleração e a eficiência
da implementação paralela. A método de paralelismo apresentou resultados satisfatórios em um
menor tempo de processamento e com desempenho aceitável. / 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 consists in
the choice of the regularization parameter in the appropriate compromise between accuracy and
stability of the solution. A method developed by researchers of IPRJ and UFRJ, operating in the
area of inverse problems, consists on minimizing a functional of residues through a functional
parameter Tikhonovs regularization. A strategy that uses the iterative search of this parameter
aiming at to get a minimum value for the functional in the following iteration was adopted recently
in a serial algorithm of restoration. However, the computational cost is a factor problem
found when using the iterative search. With this approach, an implementation in C++ language
was made using techniques of parallel computation using MPI (Message Passing Interface) for
the in the choice of the regularization parameter in the appropriate compromise between accuracy
and stability of the soluton with the method of iterative search, thus reducing, the time of
execution required for the algorithm. A modified version of the Jacobi method is considered
to be two versions of the algorithm, one serial and one parallel. This algorithm is adequate for
parallel implementation because it has no data dependencies such as the Gauss-Seidel method
is also shown to converge. As indicating of performance for evaluation of the restoration algorithm,
in addition to the traditional measures, new metric that is based on subjective criteria
called IWMSE (InformationWeighted Mean Square Error) is used. These metrics were introduced
in the program of image processing and allow to make the analysis of the restoration to each
step of iteration. The results obtained using the two possible versions verify the efficiency of
acceleration and the parallel implementation. The method of parallelism achieved satisfactory
results in a shorter processing time and with acceptable performance.
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Utilisation de l'élargissement d'opérateurs maximaux monotones pour la résolution d'inclusions variationnelles / Using the expansion of maximal monotone operators for solving variational inclusionsNagesseur, Ludovic 30 October 2012 (has links)
Cette thèse est consacrée à la résolution d'un problème fondamental de l'analyse variationnelle qu'est la recherchede zéros d'opérateurs maximaux monotones dans un espace de Hilbert. Nous nous sommes tout d'abord intéressés au cas de l'opérateur somme étendue de deux opérateurs maximaux monotones; la recherche d'un zéro de cet opérateur est un problème dont la bibliographie est peu fournie: nous proposons une version modifiée de l'algorithme d'éclatement forward-backward utilisant à chaque itération, l'epsilon-élargissement d'un opérateur maximal monotone,afin de construire une solution. Nous avons ensuite étudié la convergence d'un nouvel algorithme de faisceaux pour construire ID zéro d'un opérateur maximal monotone quelconque en dimension finie. Cet algorithme fait intervenir une double approximation polyédrale de l'epsilon-élargissement de l'opérateur considéré / This thesis is devoted to solving a basic problem of variational analysis which is the search of zeros of maximal monotone operators in a Hilbert space. First of aIl, we concentrate on the case of the extended som of two maximal monotone operators; the search of a zero of this operator is a problem for which the bibliography is not abondant: we purpose a modified version of the forward-backward splitting algorithm using at each iteration, the epsilon-enlargement of a maximal monotone operator, in order to construet a solution. Secondly, we study the convergence of a new bondie algorithm to construet a zero of an arbitrary maximal monotone operator in a finite dimensional space. In this algorithm, intervenes a double polyhedral approximation of the epsilon-enlargement of the considered operator
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Analýza variant paralelního provozu oblastí 110 kV Čebín a Sokolnice / The analysis of parallel operation variants of supply areas 110 kV Čebín and SokolniceReiter, Martin January 2016 (has links)
The diploma thesis is focused on the analysis of parallel operation of Čebín and Sokolnice substations. Different variants of parallel operation are researched. A calculation of steady state by the iterative method is described in the theoretical part. The next part briefly mentions a short-circuit and dimensioning of conductors. The possibility of overloading of lines and transformers is discussed in the last chapter of the theoretical part. The current state of the situation is described in the practical part. Main goal of the practical part of the diploma thesis is to design a configuration capable to parallel operation. Also another configuration of supply of this area is designed. There must be no direct connection between Čebín and Sokolnice substations on 110kV level in this configuration. This configuration should eliminate a transit flow of power. Each configuration has to fulfill the requirements on the steady state and on short-circuit current capability. One of the last chapters is focused on the steps, that should by undertaken to prevent transit flow of power.
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