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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.
71

Traces in and out: a deconstructionist reading of English translations of Jacques Prevert's Paroles (1946/7)

Malabo, Diane 03 March 2010 (has links)
Abstract This study is a comparative analysis of selected poems from Jacques Prévert’s Paroles (1946/1947). It is an application of a mainstreamed theoretical paradigm comprising deconstruction, hermeneutics and relevance. The overall aim is to show how each translator of Jacques Prévert derived latent and relatively obvious semantic possibilities from the ST. This objective is attained through a descriptive analysis of the translation process, and an attempt to interpret the findings thereby revealed, primarily according to the tenets of deconstruction, and according to the tenets of hermeneutics and relevance if possible. The theoretical model that grounds the study is a non-reductionist, non-prescriptivist and non-evaluative. That is the reason why the traditional terminology associated with some of the theoretical aspects mainstreamed in the model have been adapted to fit in with the general aim of the study. Actual reading experiences hardly entail a consecutive reading of more than one text. But this research is like a laboratory experiment; it tests the applicability of integrated [theoretical] formulae to a hypothetical case, the consecutive reading of selected poems from Paroles (1946/1947) and their English translations.
72

Cut finite element methods on parametric multipatch surfaces

Jonsson, Tobias January 2019 (has links)
No description available.
73

A new adaptive multiscale finite element method with applications to high contrast interface problems

Millward, Raymond January 2011 (has links)
In this thesis we show that the finite element error for the high contrast elliptic interface problem is independent of the contrast in the material coefficient under certain assumptions. The error estimate is proved using a particularly technical proof with construction of a specific function from the finite dimensional space of piecewise linear functions. We review the multiscale finite element method of Chu, Graham and Hou to give clearer insight. We present some generalisations to extend their work on a priori contrast independent local boundary conditions, which are then used to find multiscale basis functions by solving a set of local problems. We make use of their regularity result to prove a new relative error estimate for both the standard finte element method and the multiscale finite element method that is completely coefficient independent. The analytical results we explore in this thesis require a complicated construction. To avoid this we present an adaptive multiscale finite element method as an enhancement to the adaptive local-global method of Durlofsky, Efendiev and Ginting. We show numerically that this adaptive method converges optimally as if the coefficient were smooth even in the presence of singularities as well as in the case of a realisation of a random field. The novel application of this thesis is where the adaptive multiscale finite element method has been applied to the linear elasticity problem arising from the structural optimisation process in mechanical engineering. We show that a much smoother sensitivity profile is achieved along the edges of a structure with the adaptive method and no additional heuristic smoothing techniques are needed. We finally show that the new adaptive method can be efficiently implemented in parallel and the processing time scales well as the number of processors increases. The biggest advantage of the multiscale method is that the basis functions can be repeatedly used for additional problems with the same high contrast material coefficient.
74

Dimensionamento de sobressalentes: um estudo de caso baseado no conhecimento a priori

LYRA, Rodrigo Silva Pereira de 31 January 2010 (has links)
Made available in DSpace on 2014-06-12T17:39:28Z (GMT). No. of bitstreams: 2 arquivo516_1.pdf: 2278956 bytes, checksum: 44db0be5f0ee5ab60ac2d74f76fd8ab3 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2010 / O dimensionamento do estoque de sobressalentes constitui uma das mais criticas etapas no planejamento dos recursos de manutenção em função do impacto destes estoques sobre o desempenho dos equipamentos, através dos tempos de manutenção e do montante financeiro envolvido nesta atividade. Este trabalho trata de um estudo de caso envolvendo equipamentos não sujeitos ao efeito do desgaste das Indústrias Reunidas Raymundo da Fonte S/A, para os quais se deseja quantificar uma reserva técnica que garantam um nível de desempenho especificado e auxiliar na decisão do dimensionamento de sobressalentes através da definição da margem de segurança pela empresa. O modelo conceitual abordado neste estudo, cujo modelo probabilístico adotado é usado em diversas áreas se constitui de uma alternativa consagrada para o dimensionamento de sobressalentes, foi utilizada a abordagem do risco de quebra de estoque com o uso do conhecimento a priori apresentado em Almeida e Souza (2001) para o dimensionamento da quantidade de sobressalentes utilizando o método de Raiffa (1970) para elicitação. A disponibilidade do sistema produtivo da empresa é preponderantemente afetada em função da ausência de sobressalentes justificando a elaboração deste trabalho. Com a aplicação do modelo observou-se a oportunidade de gerar uma redução do montante financeiro aplicado no estoque de sobressalentes no valor de R$ 158.415,18, bem como a oportunidade de aplicá-lo em outros itens gerando uma maior mantenabilidade. Desta maneira, este estudo visa contribuir com a utilização de métodos adequados na área de gestão da manutenção, considerando que os tópicos abordados para os equipamentos produtivos das Industrias Reunidas Raymundo da Fonte podem ser utilizados em outras aplicações, guardando suas particularidades
75

Contribution à la résolution numérique des problèmes de Helmholtz

Grigoroscuta-Strugaru, Magdalena 18 December 2009 (has links) (PDF)
Dans ce travail, nous nous sommes intéressés au développement et à l'analyse numérique de méthodes numériques capables de résoudre efficacement les problèmes de Helmholtz à 2D, notamment en régime moyenne et haute fréquence. La méthode que nous proposons s'inscrit dans la lignée des méthodes de type Galerkin discontinues (DG). Dans chaque élément du maillage, la solution est approchée en utilisant une superposition d'ondes planes. La continuité de la solution aux interfaces est renforcée en utilisant des multiplicateurs de Lagrange. La méthodologie proposée est une procédure en deux étapes: nous résolvons d'abord des problèmes locaux bien posés et ensuite un système global issu de la condition de continuité imposée sur les interfaces. Les plus importantes propriétés de la méthode sont: (a) les problèmes locaux obtenus sont associés à des matrices Hermitiennes et définies positives et (b) le système global, à résoudre dans la deuxième étape, est associé à une matrice Hermitienne et semi-définie positive. Les résultats numériques obtenus montrent la supériorité de la méthode proposée par rapport aux méthodes de type élément fini standard, mais aussi par rapport à d'autres méthodes de type DG, comme par exemple celle développée par Farhat et al (2003).
76

Développement d'une approche de type LES pour la simulation d'écoulements diphasiques avec interface. Application à l'atomisation primaire.

Trontin, Pierre 26 November 2009 (has links) (PDF)
Alors que la simulation aux grandes échelles (L.E.S.) des écoulements monophasiques est largement répandue même dans le monde industriel, ce n'est pas le cas pour la L.E.S. d'écoulements diphasiques avec interface (c'est-à-dire d'écoulements où les deux phases liquide et gazeuse sont séparées par une interface). La difficulté majeure réside dans le développement de modèles de sous-maille adaptés au caractère diphasique de l'écoulement. Le but de ce travail est de générer une base D.N.S. dans le cadre d'écoulements diphasiques turbulents avec interface pour comprendre les interactions entre les petites échelles turbulentes et l'interface. Les différents termes sous-maille proviendront d'une analyse a priori de cette base D.N.S. Pour mener à bien ce travail, différentes techniques numériques sont testées et comparées dans le cadre de configurations turbulentes où de grandes déformations interfaciales apparaissent. Puis, l'interaction interface/turbulence est étudiée dans le cadre où les deux phases, séparées par une interface largement déformée, sont résolues par une approche D.N.S. La configuration retenue est l'interaction entre une nappe initialement plane et une T.H.I. libre. Les rapports de densités et de viscosités sont fixés à 1 pour se concentrer sur l'effet du coefficient de tension de surface. Une étude paramétrique sur le nombre de Weber est menée. Finalement, un filtrage a priori de la base D.N.S. est réalisé et les termes sous-maille qui en découlent sont comparés les uns aux autres.
77

Finite Element Methods for Thin Structures with Applications in Solid Mechanics

Larsson, Karl January 2013 (has links)
Thin and slender structures are widely occurring both in nature and in human creations. Clever geometries of thin structures can produce strong constructions while requiring a minimal amount of material. Computer modeling and analysis of thin and slender structures have their own set of problems, stemming from assumptions made when deriving the governing equations. This thesis deals with the derivation of numerical methods suitable for approximating solutions to problems on thin geometries. It consists of an introduction and four papers. In the first paper we introduce a thread model for use in interactive simulation. Based on a three-dimensional beam model, a corotational approach is used for interactive simulation speeds in combination with adaptive mesh resolution to maintain accuracy. In the second paper we present a family of continuous piecewise linear finite elements for thin plate problems. Patchwise reconstruction of a discontinuous piecewise quadratic deflection field allows us touse a discontinuous Galerkin method for the plate problem. Assuming a criterion on the reconstructions is fulfilled we prove a priori error estimates in energy norm and L2-norm and provide numerical results to support our findings. The third paper deals with the biharmonic equation on a surface embedded in R3. We extend theory and formalism, developed for the approximation of solutions to the Laplace-Beltrami problem on an implicitly defined surface, to also cover the biharmonic problem. A priori error estimates for a continuous/discontinuous Galerkin method is proven in energy norm and L2-norm, and we support the theoretical results by numerical convergence studies for problems on a sphere and on a torus. In the fourth paper we consider finite element modeling of curved beams in R3. We let the geometry of the beam be implicitly defined by a vector distance function. Starting from the three-dimensional equations of linear elasticity, we derive a weak formulation for a linear curved beam expressed in global coordinates. Numerical results from a finite element implementation based on these equations are compared with classical results.
78

Apriority in Naturalized Epistemology: Investigation into a Modern Defense

Christiansen, Jesse Giles 28 November 2007 (has links)
Versions of naturalized epistemology that overlook or reject apriority ignore innate belief-forming processes that provide much of the grounding for epistemic warrant. A rigorous analysis reveals that non-experiential ways of viewing apriority, such as innateness, establish the domain for a plausible naturalistic theory of a priori warrant. A moderate version of naturalistic epistemology that embraces the non-experiential feature of apriority and motivates future cognitive scientific research is the preferred account.
79

Discontinuous Galerkin methods for spectral wave/circulation modeling

Meixner, Jessica Delaney 03 October 2013 (has links)
Waves and circulation processes interact in daily wind and tide driven flows as well as in more extreme events such as hurricanes. Currents and water levels affect wave propagation and the location of wave-breaking zones, while wave forces induce setup and currents. Despite this interaction, waves and circulation processes are modeled separately using different approaches. Circulation processes are represented by the shallow water equations, which conserve mass and momentum. This approach for wind-generated waves is impractical for large geographic scales due to the fine resolution that would be required. Therefore, wind-waves are instead represented in a spectral sense, governed by the action balance equation, which propagates action density through both geographic and spectral space. Even though wind-waves and circulation are modeled separately, it is important to account for their interactions by coupling their respective models. In this dissertation we use discontinuous-Galerkin (DG) methods to couple spectral wave and circulation models to model wave-current interactions. We first develop, implement, verify and validate a DG spectral wave model, which allows for the implementation of unstructured meshes in geographic space and the utility of adaptive, higher-order approximations in both geographic and spectral space. We then couple the DG spectral wave model to an existing DG circulation model, which is run on the same geographic mesh and allows for higher order information to be passed between the two models. We verify and validate coupled wave/circulation model as well as analyzing the error of the coupled wave/circulation model. / text
80

Analysis, implementation, and verification of a discontinuous galerkin method for prediction of storm surges and coastal deformation

Mirabito, Christopher Michael 14 October 2011 (has links)
Storm surge, the pileup of seawater occurring as a result of high surface stresses and strong currents generated by extreme storm events such as hurricanes, is known to cause greater loss of life than these storms' associated winds. For example, inland flooding from the storm surge along the Gulf Coast during Hurricane Katrina killed hundreds of people. Previous storms produced even larger death tolls. Simultaneously, dune, barrier island, and channel erosion taking place during a hurricane leads to the removal of major flow controls, which significantly affects inland inundation. Also, excessive sea bed scouring around pilings can compromise the structural integrity of bridges, levees, piers, and buildings. Modeling these processes requires tightly coupling a bed morphology equation to the shallow water equations (SWE). Discontinuous Galerkin finite element methods (DGFEMs) are a natural choice for modeling this coupled system, given the need to solve these problems on large, complicated, unstructured computational meshes, as well as the desire to implement hp-adaptivity for capturing the dynamic features of the solution. Comprehensive modeling of these processes in the coastal zone presents several challenges and open questions. Most existing hydrodynamic models use a fixed-bed approach; the bottom is not allowed to evolve in response to the fluid motion. With respect to movable-bed models, there is no single, generally accepted mathematical model in use. Numerical challenges include coupling models of processes that exhibit disparate time scales during fair weather, but possibly similar time scales during intense storms. The main goals of this dissertation include implementing a robust, efficient, tightly-coupled morphological model using the local discontinuous Galerkin (LDG) method within the existing Advanced Circulation (ADCIRC) modeling framework, performing systematic code and model verification (using test cases with known solutions, proven convergence rates, or well-documented physical behavior), analyzing the stability and accuracy of the implemented numerical scheme by way of a priori error estimates, and ultimately laying some of the necessary groundwork needed to simultaneously model storm surges and bed morphodynamics during extreme storm events. / text

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