Un préconditionneur à deux niveaux, reposant sur la technique d’accélération d’Aitken d’une suite de q vecteurs solutions de l’interface d’un pro- cessus itératif de Schwarz Additif Restreint, est conçu. Cette nouvelle technique, dénomée ARAS(q), utilise une approximation grossière de la solution sur l’interface. Différentes méthodes sont proposées, aboutissant au développement d’une tech- nique d’approximation par Décomposition en Valeures Singulières de la suite de vecteurs. Des implémentations parallèles des méthodes d’Aitken-Schwarz sont pro- posées et l’étude conduit à l’implémentation d’un code totalement algébrique, sur un ou deux niveaux de parallélisation MPI, écrit dans l’environnement de la biblio- thèque PETSc. Cette implémentation pleinement parallèle et algébrique procure un outil flexible pour la résolution de systèmes linéaires tels que ceux issus de la dif- férentiation automatique des solutions de Navier-Stokes dépendant des paramètres de la simulation / A two level preconditioner, based on the Aitken acceleration technique of a sequence of q interface’s solution vectors of the Restricted Additive Schwarz iterative process, is designed. This new technique, called ARAS(q), uses a coarse approximation of the solution on the interface. Different methods are discussed, leading to the development of an approximation technique by Singular Value De- composition of the sequence of vectors. Parallel implementations of Aitken-Schwarz methods are proposed, and the study leads to a fully algebraic one-level and two- level MPI implementation of ARAS(q) written into the PETSc library framework. This fully parallel and algebraic code gives an adaptive tool to solve linear systems such as those arising from automatic differentiation of compressible Navier-Stokes solution with respect to the simulation’s parameters

Cette thèse présente un ensemble de routines pour la résolution des grands systèmes linéaires creuses sur des architectures parallèles. Les approches proposées s'inscrivent dans un schéma hybride combinant les méthodes directes et itératives à travers l'utilisation des techniques de décomposition de domaine. Dans un tel schéma, le problème initial est divisé en sous-problèmes en effectuant un partitionnement du graphe de la matrice coefficient du système. Les méthodes de Schwarz sont ensuite utilisées comme outils de préconditionnements des méthodes de Krylov basées sur GMRES. Nous nous intéressons tout d'abord au schéma utilisant un préconditionneur de Schwarz multiplicatif. Nous définissons deux niveaux de parallélisme: le premier est associé à GMRES préconditionné sur le système global et le second est utilisé pour résoudre les sous-systèmes à l'aide d'une méthode directe parallèle. Nous montrons que ce découpage permet de garantir une certaine robustesse à la méthode en limitant le nombre total de sous-domaines. De plus, cette approche permet d'utiliser plus efficacement tous les processeurs alloués sur un noeud de calcul. Nous nous intéressons ensuite à la convergence et au parallélisme de GMRES qui est utilisée comme accélerateur global dans l'approche hybride. L'observation générale est que le nombre global d'itérations, et donc le temps de calcul global, augmente avec le nombre de partitions. Pour réduire cet effet, nous proposons plusieurs versions de GMRES basés sur la déflation. Les techniques de déflation proposées utilisent soit un préconditionnement adaptatif soit une base augmentée. Nous montrons l'utilité de ces approches dans leur capacité à limiter l'influence du choix d'une taille de base de Krylov adaptée, et donc à éviter une stagnation de la méthode hybride globale. De plus, elles permettent de réduire considérablement le coût mémoire, le temps de calcul ainsi que le nombre de messages échangés par les différents processeurs. Les performances de ces méthodes sont démontrées numériquement sur des systèmes linéaires de grande taille provenant de plusieurs champs d'application, et principalement de l'optimisation de certains paramètres de conception en dynamique des fluides.

Background. A number of commentators (Holloway 1996 Muijen 1996a; 1996b) have suggested that two events in the form of homicides carried out by mental health service users came to exert a disproportionate influence on English mental health policy over the period 1985-2000. In particular it has been suggested that the events formed the focus for a ‘moral panic’ caused by ‘irresponsible’ and ‘sensationalist’ reporting in UK newspapers (Neal 1998; Prins and Swan 1998). Aims. In the light of such claims this study critically explores the role played by the deaths of Jonathan Zito and Isabel Schwarz play in establishing violent assaults perpetrated by people experiencing mental illness as a ‘social problem’. It examines whether a shift in the discourse on mental illness took place in UK newspapers and explores how the deaths of Isabel Schwarz were and Jonathan Zito were framed in terms of causal responsibility. Finally it evaluates what influence, if any, the deaths in question had on the social policy agenda. Design. Case study / mixed design integrating quantitative and qualitative methods. Method. Content analysis consisting of a longitudinal analysis of the nature of the representation of mental illness changed over the period in two UK newspaper. Framing a sub-type of discourse analysis examined changes in the discourse of mental illness and the effects of the emergence of the community care tragedy as a ‘new’ narrative. It was also used to examine the potential influence on social policy on mental illness of changes in societal level frames particularly the emergence of the risk society. Results. The content analysis found that mental illness appeared increasingly in the context of a threat to public safety in newspapers over the period but that the overall representation was more balanced. The framing analysis identified and evidenced a competitive process in framing the issue of homicides committed by service users with mental health problems and demonstrated the potential influence of macro level social frames on the policy making proces

Cette thèse présente une contribution aux développements de méthodes numériques pour la simulation d'écoulements en milieu poreux, en particulier par des méthodes de décomposition de domaine espace--temps qui permettent l'utilisation de pas de temps différents dans les différents sous--domaines. Nous étudions deux types de méthodes: la première est basée sur une généralisation de l'opérateur de Steklov-Poincaré au cas de problèmes dépendants du temps, et la seconde est basée sur la méthode de Relaxation d'Onde Optimisée de Schwarz (OSWR) dans laquelle des conditions de transmission plus générales (Robin ou Ventcell) sont utilisées pour accélérer la convergence de l'algorithme. Ces deux méthodes sont étudiées sur une formulation mixte qui est bien adaptée à la modélisation de l'écoulement et du transport en milieu poreux. Nous considérons tout d'abord un problème de diffusion et formulons, pour chaque méthode, un problème sur l'interface espace -temps entre les sous-domaines. Le caractère bien posé de ces problèmes, avec des conditions aux limites de Dirichlet ou de Robin, est démontré. Les preuves de convergence de l'algorithme OSWR et de sa version semi-discrète sous forme mixte sont également données. Des expériences numériques sont menées en 2D pour comparer les performances des deux méthodes sur des problèmes fortement hétérogènes, et un préconditionneur de Neumann--Neumann dépendant du temps permet d'accélérer la première méthode. Les deux méthodes sont ensuite étendues au cas d'une équation d'advection-diffusion, l'advection et la diffusion étant traitées séparément grâce une technique de séparation d'opérateurs, ce qui permet d'utiliser des pas de temps différents pour les deux phénomènes dans chaque sous-domaine. Des conditions de transmission sont proposées séparément pour l'advection et pour la diffusion. La convergence des méthodes est étudiée sur des exemples numériques, pour des problèmes en régime d'advection dominante ou de diffusion dominante, et leur précision en temps est étudiée dans le cas de grilles non-conformes en temps. Deux exemples inspirés de la simulation du stockage de déchets nucléaires sont étudiés, et la simulation sur des temps longs est réalisée par l'intermédiaire de fenêtres en temps. Nous considérons également la méthode OSWR avec des conditions de transmission de Ventcell, étendues à la formulation mixte. Nous démontrons que les problèmes de sous--domaine avec des conditions aux limites de Ventcell sont bien posés. Nous comparons les performances des paramètres optimisés pour Ventcell et Robin dans le cas de problèmes hétérogènes pour une décomposition en deux sous-domaines. Enfin, nous étudions l'extension des deux méthodes au cas où l'interface représente une fracture pour un modèle réduit d'écoulement dans un milieu poreux fracturé.

In this thesis Generalized Additive Neural Networks (GANNs) are studied in the context of predictive Data Mining. A GANN is a novel neural network implementation of a Generalized Additive Model. Originally GANNs were constructed interactively by considering partial residual plots. This methodology involves subjective human judgment, is time consuming, and can result in suboptimal results. The newly developed automated construction algorithm solves these difficulties by performing model selection based on an objective model selection criterion. Partial residual plots are only utilized after the best model is found to gain insight into the relationships between inputs and the target. Models are organized in a search tree with a greedy search procedure that identifies good models in a relatively short time. The automated construction algorithm, implemented in the powerful SAS® language, is nontrivial, effective, and comparable to other model selection methodologies found in the literature. This implementation, which is called AutoGANN, has a simple, intuitive, and user-friendly interface. The AutoGANN system is further extended with an approximation to Bayesian Model Averaging. This technique accounts for uncertainty about the variables that must be included in the model and uncertainty about the model structure. Model averaging utilizes in-sample model selection criteria and creates a combined model with better predictive ability than using any single model. In the field of Credit Scoring, the standard theory of scorecard building is not tampered with, but a pre-processing step is introduced to arrive at a more accurate scorecard that discriminates better between good and bad applicants. The pre-processing step exploits GANN models to achieve significant reductions in marginal and cumulative bad rates. The time it takes to develop a scorecard may be reduced by utilizing the automated construction algorithm. / Thesis (Ph.D. (Computer Science))--North-West University, Potchefstroom Campus, 2006.

In this thesis Generalized Additive Neural Networks (GANNs) are studied in the context of predictive Data Mining. A GANN is a novel neural network implementation of a Generalized Additive Model. Originally GANNs were constructed interactively by considering partial residual plots. This methodology involves subjective human judgment, is time consuming, and can result in suboptimal results. The newly developed automated construction algorithm solves these difficulties by performing model selection based on an objective model selection criterion. Partial residual plots are only utilized after the best model is found to gain insight into the relationships between inputs and the target. Models are organized in a search tree with a greedy search procedure that identifies good models in a relatively short time. The automated construction algorithm, implemented in the powerful SAS® language, is nontrivial, effective, and comparable to other model selection methodologies found in the literature. This implementation, which is called AutoGANN, has a simple, intuitive, and user-friendly interface. The AutoGANN system is further extended with an approximation to Bayesian Model Averaging. This technique accounts for uncertainty about the variables that must be included in the model and uncertainty about the model structure. Model averaging utilizes in-sample model selection criteria and creates a combined model with better predictive ability than using any single model. In the field of Credit Scoring, the standard theory of scorecard building is not tampered with, but a pre-processing step is introduced to arrive at a more accurate scorecard that discriminates better between good and bad applicants. The pre-processing step exploits GANN models to achieve significant reductions in marginal and cumulative bad rates. The time it takes to develop a scorecard may be reduced by utilizing the automated construction algorithm. / Thesis (Ph.D. (Computer Science))--North-West University, Potchefstroom Campus, 2006.

Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-07-05T19:06:39Z No. of bitstreams: 1 LUÍS PAULO DE LACERDA CAVALCANTE - DISSERTAÇÃO PPGMAT 2004..pdf: 642073 bytes, checksum: c3ee64c49aee5eeb339a7adcd8770341 (MD5) / Made available in DSpace on 2018-07-05T19:06:39Z (GMT). No. of bitstreams: 1 LUÍS PAULO DE LACERDA CAVALCANTE - DISSERTAÇÃO PPGMAT 2004..pdf: 642073 bytes, checksum: c3ee64c49aee5eeb339a7adcd8770341 (MD5) Previous issue date: 2004-10-22 / Neste trabalho estudamos a existência de soluções positivas para a seguinte classe de problemas −∆u+λu=Q(x)|u|p−2u em Ω, onde Ω é um domínio não limitado do RN. Usando métodos variacionais e argumentos desenvolvidos por P. L. Lions [14], Strauss [16], Willem [18] e Benci & Cerami [4], mostramos a existência de soluções positivas quando Ω = RN ou Ω um domínio exterior. / In this work, we are studying the existence of positive solutions for the following class of problem: −∆u+λu=Q(x)|u|p−2u em Ω, where Ω is a unbounded domain inRN. Using variational methods and arguments developed by P. L. Lions [14], Strauss [16], Willem [18] and Benci& Cerami [4], let us show the existence of positive solutions whenΩ=RN andΩ is an exterior domain.

Este trabalho procura desenvolver a tese de Roberto Schwarz em Ao vencedor as batatas (1977) e Um mestre na periferia do capitalismo (1990) e tem o intuito de ser uma interpretação do romance Memórias póstumas de Brás Cubas, escrito por Machado de Assis e publicado em livro em 1881. Para Schwarz, a elite brasileira do século XIX era volúvel em seu tratamento com a política, com as idéias e com a alteridade - escravos e dependentes. Tal volubilidade teria sido imitada no romance, por meio de uma narrativa volúvel, não apenas no conteúdo, mas sobretudo na forma. A dissertação se ocupa de buscar uma gênese para as idéias de Schwarz e entender alguns de seus pressupostos, para então ler o romance a partir de uma conscientização desses pressupostos. Ficou evidenciada a necessidade de uma plataforma de leitura que incorpore o reconhecimento da alteridade social em relação à lógica apresentada no romance, que é, segundo Schwarz postula, o modo de ser da elite. Postula-se que o narrador das Memórias é um narrador iludido a respeito do próprio poder e que o romance ficcionaliza a decadência das relações de produção escravistas e não a hegemonia do escravismo, como a fortuna crítica tem consagrado. Uma vez estabelecida a ficcionalização da derrocada da classe hegemônica no escravismo, a dissertação reconsidera a identidade entre a volubilidade do narrador e a volubilidade da elite da época, evidenciando que o romance pode ser lido com uma lógica diversa da volúvel, embora, em termos formais, a volubilidade continue sendo excelente explicação do movimento narrativo. Com isso, reconhece-se que o romance trabalha a estrutura de classes de sua época, mas salienta-se que o faz para expor e ridicularizar um poder que ilude a si mesmo a respeito de suas possibilidades de ação e influência. Neste sentido, ao criticar o aparente silenciamento absoluto da alteridade, de que resulta o poder imaginário do narrador, constrói-se uma função mediadora para ler o romance por uma visada que possa ajudar na compreensão atual de aspectos da organização social e alguns de seus preconceitos. / This thesis aims at discussing Roberto Schwarz's ideas presented in Ao vencedor as batatas (1977) and Um mestre na periferia do capitalismo (1990). It also intends to be an interpretation of the novel Memórias póstumas de Brás Cubas, written by Machado de Assis and published in 1881. Schwarz claims that the Brazilian upper-classes of the XIX century had a fickle character that was reflected in the way they dealt with politics, ideas and alterity. According to Schwarz, this fickleness was mapped onto the novel content and form, represented by the way the first person narrator behaves. The thesis is concerned in finding the presuppositions of Roberto Schwarz's ideas, in order to evaluate the novel with an awareness of these presuppositions. It turned out to be necessary to apply a different theoretical background that could provide a recognition of the social alterity. Then, the objective is to provide an account to make it possible to map the boundaries of the narrator's point of view. We claim that the novel's narrator is deceived about his own power and that the novel fictionalizes the decay of the slavish relation of production, instead of the slavery system hegemony, as most of the scholars say. Then, this study reformulates the parallel between the narrator's fickleness and the upper-classes' fickleness, lightening that the novel could be interpreted in a different way, even that in formal aspects the fickleness is able to explain the novel accurately. Concluding, the novel fictionalizes the hierarchy of classes that was present in the XIX century, but at the same time it mocks a decadent power that deceives itself in relation to its action and influence possibilities. In this sense, the apparent silencing of the alterity, from which the narrator's imaginary power arises, has a mediator function essential to a critical understanding of the novel in a democratic and multidimensional fashion, which can help to comprehend the current social organization and prejudices.

Este trabalho procura desenvolver a tese de Roberto Schwarz em Ao vencedor as batatas (1977) e Um mestre na periferia do capitalismo (1990) e tem o intuito de ser uma interpretação do romance Memórias póstumas de Brás Cubas, escrito por Machado de Assis e publicado em livro em 1881. Para Schwarz, a elite brasileira do século XIX era volúvel em seu tratamento com a política, com as idéias e com a alteridade - escravos e dependentes. Tal volubilidade teria sido imitada no romance, por meio de uma narrativa volúvel, não apenas no conteúdo, mas sobretudo na forma. A dissertação se ocupa de buscar uma gênese para as idéias de Schwarz e entender alguns de seus pressupostos, para então ler o romance a partir de uma conscientização desses pressupostos. Ficou evidenciada a necessidade de uma plataforma de leitura que incorpore o reconhecimento da alteridade social em relação à lógica apresentada no romance, que é, segundo Schwarz postula, o modo de ser da elite. Postula-se que o narrador das Memórias é um narrador iludido a respeito do próprio poder e que o romance ficcionaliza a decadência das relações de produção escravistas e não a hegemonia do escravismo, como a fortuna crítica tem consagrado. Uma vez estabelecida a ficcionalização da derrocada da classe hegemônica no escravismo, a dissertação reconsidera a identidade entre a volubilidade do narrador e a volubilidade da elite da época, evidenciando que o romance pode ser lido com uma lógica diversa da volúvel, embora, em termos formais, a volubilidade continue sendo excelente explicação do movimento narrativo. Com isso, reconhece-se que o romance trabalha a estrutura de classes de sua época, mas salienta-se que o faz para expor e ridicularizar um poder que ilude a si mesmo a respeito de suas possibilidades de ação e influência. Neste sentido, ao criticar o aparente silenciamento absoluto da alteridade, de que resulta o poder imaginário do narrador, constrói-se uma função mediadora para ler o romance por uma visada que possa ajudar na compreensão atual de aspectos da organização social e alguns de seus preconceitos. / This thesis aims at discussing Roberto Schwarz's ideas presented in Ao vencedor as batatas (1977) and Um mestre na periferia do capitalismo (1990). It also intends to be an interpretation of the novel Memórias póstumas de Brás Cubas, written by Machado de Assis and published in 1881. Schwarz claims that the Brazilian upper-classes of the XIX century had a fickle character that was reflected in the way they dealt with politics, ideas and alterity. According to Schwarz, this fickleness was mapped onto the novel content and form, represented by the way the first person narrator behaves. The thesis is concerned in finding the presuppositions of Roberto Schwarz's ideas, in order to evaluate the novel with an awareness of these presuppositions. It turned out to be necessary to apply a different theoretical background that could provide a recognition of the social alterity. Then, the objective is to provide an account to make it possible to map the boundaries of the narrator's point of view. We claim that the novel's narrator is deceived about his own power and that the novel fictionalizes the decay of the slavish relation of production, instead of the slavery system hegemony, as most of the scholars say. Then, this study reformulates the parallel between the narrator's fickleness and the upper-classes' fickleness, lightening that the novel could be interpreted in a different way, even that in formal aspects the fickleness is able to explain the novel accurately. Concluding, the novel fictionalizes the hierarchy of classes that was present in the XIX century, but at the same time it mocks a decadent power that deceives itself in relation to its action and influence possibilities. In this sense, the apparent silencing of the alterity, from which the narrator's imaginary power arises, has a mediator function essential to a critical understanding of the novel in a democratic and multidimensional fashion, which can help to comprehend the current social organization and prejudices.

Este trabalho procura desenvolver a tese de Roberto Schwarz em Ao vencedor as batatas (1977) e Um mestre na periferia do capitalismo (1990) e tem o intuito de ser uma interpretação do romance Memórias póstumas de Brás Cubas, escrito por Machado de Assis e publicado em livro em 1881. Para Schwarz, a elite brasileira do século XIX era volúvel em seu tratamento com a política, com as idéias e com a alteridade - escravos e dependentes. Tal volubilidade teria sido imitada no romance, por meio de uma narrativa volúvel, não apenas no conteúdo, mas sobretudo na forma. A dissertação se ocupa de buscar uma gênese para as idéias de Schwarz e entender alguns de seus pressupostos, para então ler o romance a partir de uma conscientização desses pressupostos. Ficou evidenciada a necessidade de uma plataforma de leitura que incorpore o reconhecimento da alteridade social em relação à lógica apresentada no romance, que é, segundo Schwarz postula, o modo de ser da elite. Postula-se que o narrador das Memórias é um narrador iludido a respeito do próprio poder e que o romance ficcionaliza a decadência das relações de produção escravistas e não a hegemonia do escravismo, como a fortuna crítica tem consagrado. Uma vez estabelecida a ficcionalização da derrocada da classe hegemônica no escravismo, a dissertação reconsidera a identidade entre a volubilidade do narrador e a volubilidade da elite da época, evidenciando que o romance pode ser lido com uma lógica diversa da volúvel, embora, em termos formais, a volubilidade continue sendo excelente explicação do movimento narrativo. Com isso, reconhece-se que o romance trabalha a estrutura de classes de sua época, mas salienta-se que o faz para expor e ridicularizar um poder que ilude a si mesmo a respeito de suas possibilidades de ação e influência. Neste sentido, ao criticar o aparente silenciamento absoluto da alteridade, de que resulta o poder imaginário do narrador, constrói-se uma função mediadora para ler o romance por uma visada que possa ajudar na compreensão atual de aspectos da organização social e alguns de seus preconceitos. / This thesis aims at discussing Roberto Schwarz's ideas presented in Ao vencedor as batatas (1977) and Um mestre na periferia do capitalismo (1990). It also intends to be an interpretation of the novel Memórias póstumas de Brás Cubas, written by Machado de Assis and published in 1881. Schwarz claims that the Brazilian upper-classes of the XIX century had a fickle character that was reflected in the way they dealt with politics, ideas and alterity. According to Schwarz, this fickleness was mapped onto the novel content and form, represented by the way the first person narrator behaves. The thesis is concerned in finding the presuppositions of Roberto Schwarz's ideas, in order to evaluate the novel with an awareness of these presuppositions. It turned out to be necessary to apply a different theoretical background that could provide a recognition of the social alterity. Then, the objective is to provide an account to make it possible to map the boundaries of the narrator's point of view. We claim that the novel's narrator is deceived about his own power and that the novel fictionalizes the decay of the slavish relation of production, instead of the slavery system hegemony, as most of the scholars say. Then, this study reformulates the parallel between the narrator's fickleness and the upper-classes' fickleness, lightening that the novel could be interpreted in a different way, even that in formal aspects the fickleness is able to explain the novel accurately. Concluding, the novel fictionalizes the hierarchy of classes that was present in the XIX century, but at the same time it mocks a decadent power that deceives itself in relation to its action and influence possibilities. In this sense, the apparent silencing of the alterity, from which the narrator's imaginary power arises, has a mediator function essential to a critical understanding of the novel in a democratic and multidimensional fashion, which can help to comprehend the current social organization and prejudices.