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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
131

Modelo computacional paralelo para a hidrodinâmica e para o transporte de substâncias bidimensional e tridimensional / Parallel computational model for hydrodynamics and for the scalar two-dimensional and three-dimensional transport of substances

Rizzi, Rogerio Luis January 2002 (has links)
Neste trabalho desenvolveu-se e implementou-se um modelo computacional paralelo multifísica para a simulação do transporte de substâncias e do escoamento hidrodinâmico, bidimensional (2D) e tridimensional (3D), em corpos de água. Sua motivação está centrada no fato de que as margens e zonas costeiras de rios, lagos, estuários, mares e oceanos são locais de aglomerações de seres humanos, dada a sua importância para as atividades econômica, de transporte e de lazer, causando desequilíbrios a esses ecossistemas. Esse fato impulsiona o desenvolvimento de pesquisas relativas a esta temática. Portanto, o objetivo deste trabalho é o de construir um modelo computacional com alta qualidade numérica, que possibilite simular os comportamentos da hidrodinâmica e do transporte escalar de substâncias em corpos de água com complexa configuração geométrica, visando a contribuir para seu manejo racional. Visto que a ênfase nessa tese são os aspectos numéricos e computacionais dos algoritmos, analisaram-se as características e propriedades numérico-computacionais que as soluções devem contemplar, tais como a estabilidade, a monotonicidade, a positividade e a conservação da massa. As estratégias de soluções enfocam os termos advectivos e difusivos, horizontais e verticais, da equação do transporte. Desse modo, a advecção horizontal é resolvida empregando o método da limitação dos fluxos de Sweby, e o transporte vertical (advecção e difusão) é resolvido com os métodos beta de Gross e de Crank-Nicolson. São empregadas malhas com distintas resoluções para a solução do problema multifísica. O esquema numérico resultante é semi-implícito, computacionalmente eficiente, estável e fornece acurácia espacial e temporal de segunda ordem. Os sistemas de equações resultantes da discretização, em diferenças finitas, das equações do escoamento e do transporte 3D, são de grande porte, lineares, esparsos e simétricos definidos-positivos (SDP). No caso 2D os sistemas são lineares, mas os sistemas de equações para a equação do transporte não são simétricos. Assim, para a solução de sistemas de equações SDP e dos sistemas não simétricos empregam-se, respectivamente, os métodos do subespaço de Krylov do gradiente conjugado e do resíduo mínimo generalizado. No caso da solução dos sistemas 3-diagonal, utiliza-se o algoritmo de Thomas e o algoritmo de Cholesky. A solução paralela foi obtida sob duas abordagens. A decomposição ou particionamento de dados, onde as operações e os dados são distribuídos entre os processos disponíveis e são resolvidos em paralelo. E, a decomposição de domínio, onde obtém-se a solução do problema global combinando as soluções de subproblemas locais. Em particular, emprega-se neste trabalho, o método de decomposição de domínio aditivo de Schwarz, como método de solução, e como pré-condicionador. Para maximizar a relação computação/comunicação, visto que a eficiência computacional da solução paralela depende diretamente do balanceamento de carga e da minimização da comunicação entre os processos, empregou-se algoritmos de particionamento de grafos para obter localmente os subproblemas, ou as partes dos dados. O modelo computacional paralelo resultante mostrou-se computacionalmente eficiente e com alta qualidade numérica. / A multi-physics parallel computational model was developed and implemented for the simulation of substance transport and for the two-dimensional (2D) and threedimensional (3D) hydrodynamic flow in water bodies. The motivation for this work is focused in the fact that the margins and coastal zones of rivers, lakes, estuaries, seas and oceans are places of human agglomeration, because of their importance for economic, transport, and leisure activities causing ecosystem disequilibrium. This fact stimulates the researches related to this topic. Therefore, the goal of this work is to build a computational model of high numerical quality, that allows the simulation of hydrodynamics and of scalar transport of substances behavior in water bodies of complex configuration, aiming at their rational management. Since the focuses of this thesis are the numerical and computational aspects of the algorithms, the main numerical-computational characteristics and properties that the solutions need to fulfill were analyzed. That is: stability, monotonicity, positivity and mass conservation. Solution strategies focus on advective and diffusive terms, horizontal and vertical terms of the transport equation. In this way, horizontal advection is solved using Sweby’s flow limiting method; and the vertical transport (advection and diffusion) is solved with Gross and Crank-Nicolson’s beta methods. Meshes of different resolutions are employed in the solution of the multi-physics problem. The resulting numerical scheme is semi-implicit, computationally efficient, stable and provides second order accuracy in space and in time. The equation systems resulting of the discretization, in finite differences, of the flow and 3D transport are of large scale, linear, sparse and symmetric positive definite (SPD). In the 2D case, the systems are linear, but the equation systems for the transport equation are not symmetric. Therefore, for the solution of SPD equation systems and of the non-symmetric systems we employ, respectively, the methods of Krylov’s sub-space of the conjugate gradient and of the generalized minimum residue. In the case of the solution of 3-diagonal systems, Thomas algorithm and Cholesky algorithm are used. The parallel solution was obtained through two approaches. In data decomposition or partitioning, operation and data are distributed among the processes available and are solved in parallel. In domain decomposition the solution of the global problem is obtained combining the solutions of the local sub-problems. In particular, in this work, Schwarz additive domain decomposition method is used as solution method and as preconditioner. In order to maximize the computation/communication relation, since the computational efficiency of the parallel solution depends directly of the load balancing and of the minimization of the communication between processes, graph-partitioning algorithms were used to obtain the sub-problems or part of the data locally. The resulting parallel computational model is computationally efficient and of high numerical quality.
132

Modelo computacional paralelo para a hidrodinâmica e para o transporte de substâncias bidimensional e tridimensional / Parallel computational model for hydrodynamics and for the scalar two-dimensional and three-dimensional transport of substances

Rizzi, Rogerio Luis January 2002 (has links)
Neste trabalho desenvolveu-se e implementou-se um modelo computacional paralelo multifísica para a simulação do transporte de substâncias e do escoamento hidrodinâmico, bidimensional (2D) e tridimensional (3D), em corpos de água. Sua motivação está centrada no fato de que as margens e zonas costeiras de rios, lagos, estuários, mares e oceanos são locais de aglomerações de seres humanos, dada a sua importância para as atividades econômica, de transporte e de lazer, causando desequilíbrios a esses ecossistemas. Esse fato impulsiona o desenvolvimento de pesquisas relativas a esta temática. Portanto, o objetivo deste trabalho é o de construir um modelo computacional com alta qualidade numérica, que possibilite simular os comportamentos da hidrodinâmica e do transporte escalar de substâncias em corpos de água com complexa configuração geométrica, visando a contribuir para seu manejo racional. Visto que a ênfase nessa tese são os aspectos numéricos e computacionais dos algoritmos, analisaram-se as características e propriedades numérico-computacionais que as soluções devem contemplar, tais como a estabilidade, a monotonicidade, a positividade e a conservação da massa. As estratégias de soluções enfocam os termos advectivos e difusivos, horizontais e verticais, da equação do transporte. Desse modo, a advecção horizontal é resolvida empregando o método da limitação dos fluxos de Sweby, e o transporte vertical (advecção e difusão) é resolvido com os métodos beta de Gross e de Crank-Nicolson. São empregadas malhas com distintas resoluções para a solução do problema multifísica. O esquema numérico resultante é semi-implícito, computacionalmente eficiente, estável e fornece acurácia espacial e temporal de segunda ordem. Os sistemas de equações resultantes da discretização, em diferenças finitas, das equações do escoamento e do transporte 3D, são de grande porte, lineares, esparsos e simétricos definidos-positivos (SDP). No caso 2D os sistemas são lineares, mas os sistemas de equações para a equação do transporte não são simétricos. Assim, para a solução de sistemas de equações SDP e dos sistemas não simétricos empregam-se, respectivamente, os métodos do subespaço de Krylov do gradiente conjugado e do resíduo mínimo generalizado. No caso da solução dos sistemas 3-diagonal, utiliza-se o algoritmo de Thomas e o algoritmo de Cholesky. A solução paralela foi obtida sob duas abordagens. A decomposição ou particionamento de dados, onde as operações e os dados são distribuídos entre os processos disponíveis e são resolvidos em paralelo. E, a decomposição de domínio, onde obtém-se a solução do problema global combinando as soluções de subproblemas locais. Em particular, emprega-se neste trabalho, o método de decomposição de domínio aditivo de Schwarz, como método de solução, e como pré-condicionador. Para maximizar a relação computação/comunicação, visto que a eficiência computacional da solução paralela depende diretamente do balanceamento de carga e da minimização da comunicação entre os processos, empregou-se algoritmos de particionamento de grafos para obter localmente os subproblemas, ou as partes dos dados. O modelo computacional paralelo resultante mostrou-se computacionalmente eficiente e com alta qualidade numérica. / A multi-physics parallel computational model was developed and implemented for the simulation of substance transport and for the two-dimensional (2D) and threedimensional (3D) hydrodynamic flow in water bodies. The motivation for this work is focused in the fact that the margins and coastal zones of rivers, lakes, estuaries, seas and oceans are places of human agglomeration, because of their importance for economic, transport, and leisure activities causing ecosystem disequilibrium. This fact stimulates the researches related to this topic. Therefore, the goal of this work is to build a computational model of high numerical quality, that allows the simulation of hydrodynamics and of scalar transport of substances behavior in water bodies of complex configuration, aiming at their rational management. Since the focuses of this thesis are the numerical and computational aspects of the algorithms, the main numerical-computational characteristics and properties that the solutions need to fulfill were analyzed. That is: stability, monotonicity, positivity and mass conservation. Solution strategies focus on advective and diffusive terms, horizontal and vertical terms of the transport equation. In this way, horizontal advection is solved using Sweby’s flow limiting method; and the vertical transport (advection and diffusion) is solved with Gross and Crank-Nicolson’s beta methods. Meshes of different resolutions are employed in the solution of the multi-physics problem. The resulting numerical scheme is semi-implicit, computationally efficient, stable and provides second order accuracy in space and in time. The equation systems resulting of the discretization, in finite differences, of the flow and 3D transport are of large scale, linear, sparse and symmetric positive definite (SPD). In the 2D case, the systems are linear, but the equation systems for the transport equation are not symmetric. Therefore, for the solution of SPD equation systems and of the non-symmetric systems we employ, respectively, the methods of Krylov’s sub-space of the conjugate gradient and of the generalized minimum residue. In the case of the solution of 3-diagonal systems, Thomas algorithm and Cholesky algorithm are used. The parallel solution was obtained through two approaches. In data decomposition or partitioning, operation and data are distributed among the processes available and are solved in parallel. In domain decomposition the solution of the global problem is obtained combining the solutions of the local sub-problems. In particular, in this work, Schwarz additive domain decomposition method is used as solution method and as preconditioner. In order to maximize the computation/communication relation, since the computational efficiency of the parallel solution depends directly of the load balancing and of the minimization of the communication between processes, graph-partitioning algorithms were used to obtain the sub-problems or part of the data locally. The resulting parallel computational model is computationally efficient and of high numerical quality.
133

Que horas eram para Mário e Osvaldo?

Leite, Carlos Augusto Bonifácio January 2013 (has links)
Este trabalho busca analisar as poéticas dos escritores Mário de Andrade e Oswald de Andrade ao longo dos anos 20 do século passado. Para isso, considera essencial remontar a conjuntura paulistana daquele período a fim de verificar como cada poética se relaciona a este tempo. Também fará parte do escrutínio uma visita ao que os escritores propunham em textos não intrinsicamente poéticos – prefácios, ensaios, manifestos –, bem como serão consideradas as produções narrativas ou dramáticas, quando promoverem maior precisão na análise. Na diferença formal existente entre as duas poéticas quanto a um mesmo processo social e na discriminação das variadas tensões que agem sobre cada uma das estéticas, se procurará encontrar o princípio estrutural, tal como postulado por Antonio Candido e ponto central da crítica de Roberto Schwarz sobre Machado de Assis, da poesia dos anos 20 dos dois escritores centrais do primeiro modernismo brasileiro. / This work aims to analyze the Mario de Andrade and Oswald de Andrade’s poetics through the 20s of the last century. For this, it considers essential to rebuild the São Paulo social structure in that period in order to verify how each poetic relates with that time. A visit to what these writers proposed in not intrinsically poetic texts – prefaces, essays, manifesto – will also be a part of this scrutiny, as well will be considered narrative and dramatic productions while promoting greater accuracy in the analysis. In the formal difference between these two poetics about the same social process and the discrimination of many forces that act on each aesthetic, it will aim to find the structural principal, as postulated by Antonio Candido and as axial point of the Roberto Schwarz’s work about Machado de Assis, of these writers, who are the two central names in the 20s brazilian modernism.
134

O teorema da aplicação de Riemann: uma prova livre de integração / The Riemann mapping theorem: an integration free proof

Jéssica Laís Calado de Barros 08 April 2016 (has links)
Neste trabalho, seguindo a abordagem de Weierstrass, temos o objetivo de responder a seguinte questão: conhecida a equivalência entre holomorfia e analiticidade no caso complexo, quais propriedades das funções analíticas podem ser obtidas sem assumir tal equivalência? Analisando esta situação, resultados interessantes serão obtidos sem o uso de qualquer teorema de integração complexa e, para alcançar tal objetivo, nossas principais ferramentas serão a teoria de somas não ordenadas de famílias em C e propriedades do índice de caminhos fechados. Entre os resultados apresentados estão os conhecidos Teorema Fundamental da Álgebra, Lema de Schwarz, Teorema de Montel, Teorema da Série Dupla de Weierstrass, Princípio do Argumento, Teorema de Rouché, Teorema da Fatoração de Weierstrass, Pequeno Teorema de Picard e o Teorema da Aplicação de Riemann. / In this work, following the Weierstrass\'s approach, we aim to answer the following question: knowing the equivalence between holomorphy and analyticity in the complex case, which properties of analytic functions can be obtained without assuming such equivalence? Through analyzing this situation, interesting results will be obtained without employing of any complex integration theorem and in order to achieve this goal, our main tools will be the theory of unordered sums in C and properties of winding numbers of closed paths. Among the proven results are the well known Fundamental Theorem of Algebra, Schwarz\'s Lemma, Montel\'s Theorem, Weierstrass\'s Double Series Theorem, Argument Principle, Rouché\'s Theorem, Weierstrass\'s Factorization Theorem, Picard\'s Little Theorem and the Riemann\'s Mapping Theorem.
135

"Mundo da desordem", "homem cordial" e a ordem contemporanea do capital : uma analise do esquema interpretativo de Roberto Schwarz

Re, Henrique Antonio 24 February 2005 (has links)
Orientador: Fernando Antonio Lourenço / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Filosofia e Ciencias Humanas / Made available in DSpace on 2018-08-04T03:34:56Z (GMT). No. of bitstreams: 1 Re_HenriqueAntonio_M.pdf: 12537503 bytes, checksum: 54ee64f4a603082c0e0c14278ea46ab6 (MD5) Previous issue date: 2005 / Resumo: Este trabalho procura discutir a interpretação do andamento histórico da sociedade brasileira, apresentada por Roberto Schwarz, a partir de duas de suas fontes: o livro RaÍzes do Brasil, de Sérgio Buarque de Holanda e alguns ensaios de Antonio Candido, com destaque para a "Dialética da malandragem". Este procedimento permitiu compreender de que modo algumas contribuições desses dois autores foram incorporadas ou recusadas quando da construção daquela interpretação. Possibilitou ainda compreender essas divergências como contribuições ao processo de fonnação do pensamento social brasileiro, uma vez que foram analisadas através do debate intelectual no qual surgiram / Abstract: The present dissertation strives to discuss the interpretation of the historical process of the Brazilian society presented by Roberto Schwarz, from two sources: the book Raizes do Brasil, by Sérgio Buarque de Holanda and some essays by Antonio Candido, chiefly the "Dialética da malandragem". The procedure enabled the comprehension of how the contributions of both authors were accepted or refused when that interpretation was made. It also enabled the comprehension of the divergences as contributions to the process of formation of the Brazilian social thought, since they were analyzed through the intellectual debate from which they came u / Mestrado / Sociologia / Mestre em Sociologia
136

Advanced Algorithms for Virtual Reconstruction and Finite Element Modeling of Materials with Complex Microstructures

Yang, Ming January 2021 (has links)
No description available.
137

Botanik brut: Fotografischer Beton

Mielke, Mirko 17 November 2023 (has links)
“Botanik brut“ ist eine Serie botanischer Fotografien, die analog auf Beton belichtet und entwickelt wurden. Vorliegend eine Ausarbeitung von ca. 320 Schwarz-Weiß-Kleinbildnegativen aus den Jahren 2019 bis 2022. Entstanden sind diese in den botanischen Gärten Berlin, Lissabon, Paris, Zürich und Makarska. Es ist der Versuch, die Poesie und Einzigartigkeit zwischen Natur und Kultur künstlerisch zu erforschen.
138

Comparing generalized additive neural networks with multilayer perceptrons / Johannes Christiaan Goosen

Goosen, Johannes Christiaan January 2011 (has links)
In this dissertation, generalized additive neural networks (GANNs) and multilayer perceptrons (MLPs) are studied and compared as prediction techniques. MLPs are the most widely used type of artificial neural network (ANN), but are considered black boxes with regard to interpretability. There is currently no simple a priori method to determine the number of hidden neurons in each of the hidden layers of ANNs. Guidelines exist that are either heuristic or based on simulations that are derived from limited experiments. A modified version of the neural network construction with cross–validation samples (N2C2S) algorithm is therefore implemented and utilized to construct good MLP models. This algorithm enables the comparison with GANN models. GANNs are a relatively new type of ANN, based on the generalized additive model. The architecture of a GANN is less complex compared to MLPs and results can be interpreted with a graphical method, called the partial residual plot. A GANN consists of an input layer where each of the input nodes has its own MLP with one hidden layer. Originally, GANNs were constructed by interpreting partial residual plots. This method is time consuming and subjective, which may lead to the creation of suboptimal models. Consequently, an automated construction algorithm for GANNs was created and implemented in the SAS R statistical language. This system was called AutoGANN and is used to create good GANN models. A number of experiments are conducted on five publicly available data sets to gain insight into the similarities and differences between GANN and MLP models. The data sets include regression and classification tasks. In–sample model selection with the SBC model selection criterion and out–of–sample model selection with the average validation error as model selection criterion are performed. The models created are compared in terms of predictive accuracy, model complexity, comprehensibility, ease of construction and utility. The results show that the choice of model is highly dependent on the problem, as no single model always outperforms the other in terms of predictive accuracy. GANNs may be suggested for problems where interpretability of the results is important. The time taken to construct good MLP models by the modified N2C2S algorithm may be shorter than the time to build good GANN models by the automated construction algorithm / Thesis (M.Sc. (Computer Science))--North-West University, Potchefstroom Campus, 2011.
139

Comparing generalized additive neural networks with multilayer perceptrons / Johannes Christiaan Goosen

Goosen, Johannes Christiaan January 2011 (has links)
In this dissertation, generalized additive neural networks (GANNs) and multilayer perceptrons (MLPs) are studied and compared as prediction techniques. MLPs are the most widely used type of artificial neural network (ANN), but are considered black boxes with regard to interpretability. There is currently no simple a priori method to determine the number of hidden neurons in each of the hidden layers of ANNs. Guidelines exist that are either heuristic or based on simulations that are derived from limited experiments. A modified version of the neural network construction with cross–validation samples (N2C2S) algorithm is therefore implemented and utilized to construct good MLP models. This algorithm enables the comparison with GANN models. GANNs are a relatively new type of ANN, based on the generalized additive model. The architecture of a GANN is less complex compared to MLPs and results can be interpreted with a graphical method, called the partial residual plot. A GANN consists of an input layer where each of the input nodes has its own MLP with one hidden layer. Originally, GANNs were constructed by interpreting partial residual plots. This method is time consuming and subjective, which may lead to the creation of suboptimal models. Consequently, an automated construction algorithm for GANNs was created and implemented in the SAS R statistical language. This system was called AutoGANN and is used to create good GANN models. A number of experiments are conducted on five publicly available data sets to gain insight into the similarities and differences between GANN and MLP models. The data sets include regression and classification tasks. In–sample model selection with the SBC model selection criterion and out–of–sample model selection with the average validation error as model selection criterion are performed. The models created are compared in terms of predictive accuracy, model complexity, comprehensibility, ease of construction and utility. The results show that the choice of model is highly dependent on the problem, as no single model always outperforms the other in terms of predictive accuracy. GANNs may be suggested for problems where interpretability of the results is important. The time taken to construct good MLP models by the modified N2C2S algorithm may be shorter than the time to build good GANN models by the automated construction algorithm / Thesis (M.Sc. (Computer Science))--North-West University, Potchefstroom Campus, 2011.
140

Memória da violência em Le Dernier des Justes de André Schwarz-Bart / Memory of violence in Le Dernier des Justes by André Schwarz-Bart

Deval Neto, Antônio, 1980- 24 August 2018 (has links)
Orientador: Márcio Orlando Seligmann-Silva / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Estudos da Linguagem / Made available in DSpace on 2018-08-24T15:09:41Z (GMT). No. of bitstreams: 1 DevalNeto_Antonio_M.pdf: 2278101 bytes, checksum: 76b2216dc2c1df7e5c846af5c20f050d (MD5) Previous issue date: 2014 / Resumo: O presente trabalho busca apresentar a obra de André Schwarz-Bart, o Último dos Justos, publicado em 1959, e as formas como a memória e a violência nela se inscrevem. Começamos por analisar quais são as formas de violência que o romance contempla, todas elas ligadas à história das comunidades judaicas da Europa e as perseguições por elas sofridas nos séculos que o romance pretende abordar. Além das perseguições, expulsões e massacres, outras formas de violência são abordadas, como as relações de trabalho. Também foram analisadas as formas como o romance constrói seus cenários e personagens e como eles se ligam à lenda dos Lamed-vav e à história dos judeus europeus desde a Idade Média até a Segunda Guerra Mundial. Os problemas da recepção do romance que se ligam ao período histórico conturbado pelo qual a França passava na década de 1950 também foram abordados, uma vez que, tanto o livro quanto seu autor estiveram no meio de acusações de plágio, falsificação histórica e desconhecimento do judaísmo ao mesmo tempo em que foi acolhido como um dos maiores romances franceses do século. Procuramos também demonstrar a atualidade do romance tendo em vista seu caráter universal que extrapola a questão judaica e da Shoah / Abstract: The present study aims to present the work of André Schwarz-Bart, Le dernier des Justes , published in 1959 , and the forms such as memory and violence appear in the novel. We start by analyzing what are the forms of violence included in the novel, all of them connected to the history of Jewish communities in Europe and the persecutions they suffered centuries. Beyond the persecutions, expulsions and massacres, other forms of violence are researched, such as labor relations. The ways in which the novel builds the sets and characters and how they relate to the legend of the Lamed-vav and the history of European Jews from the Middle Ages to World War II were also studied. The problems concerning the reception of the novel related to the troubled historical period by which France passed in the 1950s were also problematized, since, both, the book and the author were in the middle of accusations of plagiarism, falsification and historical ignorance of Judaism at the same time it was recognized as one of the greatest French novels of the century. Also sought to demonstrate the relevance of the novel given its universal character that goes beyond the Jewish and Holocaust issue / Mestrado / Teoria e Critica Literaria / Mestre em Teoria e História Literária

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