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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.
101

Interpretação racional de resultados de ensaios SPT com base em conceitos de energia / Rational interpretation of SPT tests results based on energy concepts

Thaise da Silva Oliveira Morais 28 November 2014 (has links)
A sondagem de simples reconhecimento do solo com medida do índice de resistência à penetração dinâmica do amostrador (NSPT), universalmente conhecida como ensaio SPT, é um dos ensaios de campo mais difundidos no Brasil. A popularidade deste ensaio deve-se a sua praticidade, baixo custo, à experiência já adquirida e a fácil utilização dos seus resultados. Entretanto, este ensaio tem sido amplamente criticado devido às variações de equipamentos e procedimentos, que causa dispersões significativas nos resultados. Usualmente, o índice NSPT é utilizado na estimativa da capacidade de carga e recalque de fundações, a partir de correlações empíricas ou semi-empíricas, o que também recebe críticas, visto que essas correlações são baseadas em observações práticas e sem fundamento científico. O índice NSPT é função da quantidade de energia entregue ao amostrador, durante o golpe no ensaio SPT. Assim, o conhecimento da eficiência permite normalizar os valores de NSPT para um valor de referência padrão. O valor padrão adotado internacionalmente, correspondente a uma eficiência de 60%. Desta forma, a análise racional dos resultados de ensaios SPT, concentra-se na estimativa das quantidades de energia envolvidas no ensaio. Neste contexto, o presente trabalho trata da interpretação racional de ensaios SPT realizados com o monitoramento das quantidades de energia envolvidas no ensaio. As energias foram obtidas indiretamente, através de sinais de força e aceleração durante a propagação da onda de tensão pela composição de haste. Para tanto, foram utilizados segmentos de hastes instrumentadas com células de carga e acelerômetros; e um sistema de aquisição de dados indicado para o monitoramento de eventos dinâmicos. Os ensaios SPT foram realizados com instrumentação dinâmica em duas seções ao longo da composição de hastes (topo e base, simultaneamente). Assim, a partir desse arranjo, foram determinadas as quantidades de energia responsáveis pela cravação do amostrador e as perdas ocorridas. A partir dos sinais de força no topo do amostrador, foram determinadas as resistências dinâmicas mobilizadas no sistema solo-amostrador devido à cravação. Estes resultados experimentais foram comparados com resultados teóricos de resistência dinâmica e estática, obtidos com base no Princípio de Hamilton. De posse dos resultados de eficiência, comprimento das amostras recuperadas e do atrito adesão entre a parede externa do amostrador e o solo, foi feito o equilíbrio das reações mobilizadas no amostrador, segundo a proposta de Aoki (2013), sendo obtidas as resistências de ponta e atrito (interno e externo) no sistema solo-amostrador. / The Standard Penetration Test (SPT) with measurement of the index of resistance to dynamic penetration of the sampler (NSPT) is one of the most widespread in situ tests in Brazil. The popularity of this test is due to its practicality, low cost, acquired experience by practitioners and simple applicability of its results. However, this test has been widely criticized because of variation in equipment and procedures, which causes significant dispersion in the results. The NSPT index is usually used to estimate the bearing capacity and settlement of foundations, using empirical or semi-empirical correlations. This fact also receives criticism, as these correlations are based on practical observations without any scientific basis. The NSPT index depends on the amount of energy delivered to the sampler, during the blow in the SPT test. Thus, knowing the equipment efficiency allows normalizing the NSPT values to a standard reference value. The international reference value corresponds to an efficiency of 60%. In this way, the rational analysis of the results of SPT tests essentially depends on the estimation of the quantities of energy involved in the test. This research presents the rational interpretation of the SPT test results based on monitoring the amounts of energy involved in the test. The energies were indirectly obtained through force and acceleration signals during the stress wave propagation along the string of rods. For this, rod subassemblies instrumented with load cells and accelerometers were used. A suitable data acquisition system for monitoring dynamic events was also used. The SPT tests were performed with instrumented subassemblies placed at two positions along the string of rods (top and bottom simultaneously). Thus, from this arrangement, the amounts of energy accountable for the sampler penetration and the energy losses occurred were determined. Likewise, the dynamic resistances mobilized in the soil-sampler system during the penetration were determined from the force and acceleration signals at the top of the sampler. These experimental results were compared with those theoretical results, based on the Principle of Hamilton. With the efficiency results, the length of recovered samples and the external skin friction in the soil-sampler system, the balance of the reactions mobilized in the sampler was verified, as proposed by Aoki (2013). Thus, the tip and skin friction (internal and external) resistances in the soil-sampler system were obtained.
102

Novel Methods for Multidimensional Image Segmentation

Pichon, Eric 03 November 2005 (has links)
Artificial vision is the problem of creating systems capable of processing visual information. A fundamental sub-problem of artificial vision is image segmentation, the problem of detecting a structure from a digital image. Examples of segmentation problems include the detection of a road from an aerial photograph or the determination of the boundaries of the brain's ventricles from medical imagery. The extraction of structures allows for subsequent higher-level cognitive tasks. One of them is shape comparison. For example, if the brain ventricles of a patient are segmented, can their shapes be used for diagnosis? That is to say, do the shapes of the extracted ventricles resemble more those of healthy patients or those of patients suffering from schizophrenia? This thesis deals with the problem of image segmentation and shape comparison in the mathematical framework of partial differential equations. The contribution of this thesis is threefold: 1. A technique for the segmentation of regions is proposed. A cost functional is defined for regions based on a non-parametric functional of the distribution of image intensities inside the region. This cost is constructed to favor regions that are homogeneous. Regions that are optimal with respect to that cost can be determined with limited user interaction. 2. The use of direction information is introduced for the segmentation of open curves and closed surfaces. A cost functional is defined for structures (curves or surfaces) by integrating a local, direction-dependent pattern detector along the structure. Optimal structures, corresponding to the best match with the pattern detector, can be determined using efficient algorithms. 3. A technique for shape comparison based on the Laplace equation is proposed. Given two surfaces, one-to-one correspondences are determined that allow for the characterization of local and global similarity measures. The local differences among shapes (resulting for example from a segmentation step) can be visualized for qualitative evaluation by a human expert. It can also be used for classifying shapes into, for example, normal and pathological classes.
103

Supportive environments for active living? a case study of local government discourses of the built and social environments and physical activity /

Ryks, Tony. January 2008 (has links)
Thesis (M.Sp.L.S.)--University of Waikato, 2008. / Title from PDF cover (viewed August 28, 2008) Includes bibliographical references (p. 145-164)
104

Mobilizing for mission rejuvenating a traditional congregation /

Bernhardt, Robert J. January 1996 (has links)
Thesis (D. Min.)--Westminster Theological Seminary, Philadelphia, 1996. / Includes vita. "An annotated bibliography on the unchurched": (leaves 116-120). Includes bibliographical references (leaves 253-256).
105

FESSENDEN’S WORLDS: BIOSYS A SHORT FILM INSPIRED BY EDMOND HAMILTON’S “FESSENDEN’S WORLDS”

Unknown Date (has links)
Fessenden’s Worlds: Biosys is a short film inspired by the 1937 short story “Fessenden’s Worlds” by Edmond Hamilton. The first chapter situates the original story in science fiction film and media, and in wider folklore. Parallels and contrasts within the storylines of the original “Fessenden’s Worlds” and the Biosys short film are discussed. The second chapter examines all production techniques used to create Fessenden’s Worlds: Biosys. Aspects of filmmaking include storyboarding and previsualization research, production design and prop building, and filming for green screen compositing. The post-production software techniques used to create Fessenden’s Worlds: Biosys are discussed, including hard surface and organic 3D modeling in Maya; texturing in Substance Painter; rendering in Arnold; particle and geometric procedural visual effects using Trapcode Particular, Mir, and Shine; and motion graphics design for device displays in Adobe After Effects. / Includes bibliography. / Thesis (M.F.A.)--Florida Atlantic University, 2021. / FAU Electronic Theses and Dissertations Collection
106

Local properties of graphs

De Wet, Johan Pieter 10 1900 (has links)
We say a graph is locally P if the induced graph on the neighbourhood of every vertex has the property P. Specically, a graph is locally traceable (LT) or locally hamiltonian (LH) if the induced graph on the neighbourhood of every vertex is traceable or hamiltonian, respectively. A locally locally hamiltonian (L2H) graph is a graph in which the graph induced by the neighbourhood of each vertex is an LH graph. This concept is generalized to an arbitrary degree of nesting, to make it possible to work with LkH graphs. This thesis focuses on the global cycle properties of LT, LH and LkH graphs. Methods are developed to construct and combine such graphs to create others with desired properties. It is shown that with the exception of three graphs, LT graphs with maximum degree no greater than 5 are fully cycle extendable (and hence hamiltonian), but the Hamilton cycle problem for LT graphs with maximum degree 6 is NP-complete. Furthermore, the smallest nontraceable LT graph has order 10, and the smallest value of the maximum degree for which LT graphs can be nontraceable is 6. It is also shown that LH graphs with maximum degree 6 are fully cycle extendable, and that there exist nonhamiltonian LH graphs with maximum degree 9 or less for all orders greater than 10. The Hamilton cycle problem is shown to be NP-complete for LH graphs with maximum degree 9. The construction of r-regular nonhamiltonian graphs is demonstrated, and it is shown that the number of vertices in a longest path in an LH graph can contain a vanishing fraction of the vertices of the graph. NP-completeness of the Hamilton cycle problem for LkH graphs for higher values of k is also investigated. / Mathematical Sciences / D. Phil. (Mathematics)
107

Numerical solution of discretised HJB equations with applications in finance

Witte, Jan Hendrik January 2011 (has links)
We consider the numerical solution of discretised Hamilton-Jacobi-Bellman (HJB) equations with applications in finance. For the discrete linear complementarity problem arising in American option pricing, we study a policy iteration method. We show, analytically and numerically, that, in standard situations, the computational cost of this approach is comparable to that of European option pricing. We also characterise the shortcomings of policy iteration, providing a lower bound for the number of steps required when having inaccurate initial data. For discretised HJB equations with a finite control set, we propose a penalty approach. The accuracy of the penalty approximation is of first order in the penalty parameter, and we present a Newton-type iterative solver terminating after finitely many steps with a solution to the penalised equation. For discretised HJB equations and discretised HJB obstacle problems with compact control sets, we also introduce penalty approximations. In both cases, the approximation accuracy is of first order in the penalty parameter. We again design Newton-type methods for the solution of the penalised equations. For the penalised HJB equation, the iterative solver has monotone global convergence. For the penalised HJB obstacle problem, the iterative solver has local quadratic convergence. We carefully benchmark all our numerical schemes against current state-of-the-art techniques, demonstrating competitiveness.
108

An analysis of the quality and quantity of reading of selected ninth grade students in Hamilton County

Leslie, Lucille Buckels Unknown Date (has links)
No description available.
109

Estudo sobre a teoria de vínculos de Hamilton-Jacobi /

Maia, N. T., (Natália Tenório) January 2013 (has links)
Orientador: Bruto Max Pimentel Escobar / Co-orientador: / Banca:Andrey Yuryevich Mikhaylov / Banca: Edmundo Capelas de Oliveira / Resumo: A teoria de Hamilton-Jacobi geralmente é apresentada como uma extensão da teoria de Hamilton através das transformações canônicas. No entanto, o matemático Constantin Carathéodory mostrou que essa teoria, sua existência e validade, independem do formalismo hamiltoniano. Neste trabalho, apresentaremos a abordagem de Carathéodory para a teoria de Hamilton-Jacobi. Partindo desse procedimento, construiremos uma teoria de vínculos para que se possa resolver problemas com vínculos involutivos e não-involutivos. Para isso, analisaremos a integrabilidade das equações e introduziremos a operação dos parênteses generalizados que, no lugar do parênteses de Poisson, passará a descrever a dinâmica de sistemas vinculados. Mostraremos uma aplicação dessa teoria de vínculos no modelo BF da teoria de campos. Para finalizar, trataremos da Termodinâmica Axiomática de Carathéodory e também da teoria de Hamilton-Jacobi na Termodinâmica, o que é válido para ilustrar a grande abrangência desse formalismo / Abstract: The Hamilton-Jacobi theory is usually presented as an extension of the Hamilton's theory through the canonical transformations. However, the mathematician Constantin Carathéodory showed this theory, its existence and validity, is independent of the Hamiltonian formalism. In this work, we present the Caratheodory's approach to the Hamilton-Jacobi theory. From this procedure, we build a theory of constraints which can solve problems with involutive and non-involutive constraints. For this, we analyze the integrability of the equations and introduce the operation of the generalized brackets that, instead of Poisson brackets, will describe the dynamics of constrained systems. We show an application of this theory in BF model of the field theory. Finally, we will discuss the Carathéodory's Axiomatic Thermodynamics and also show the Hamilton-Jacobi theory in Thermodynamics, which is valid to illustrate the wide coverage of this formalism / Mestre
110

Sistemas de controle em domínios estratificados /

Patzi Aquino, Paola Geovanna. January 2015 (has links)
Orientador: Geraldo Nunes Silva / Banca: Iguer Luis Domini dos Santos / Banca: Marko Antonio Rojas Medar / Resumo: Neste trabalho caracterizaremos sistemas dinâmicos na forma dos chamados domínios estratificados. Bressan e Hong[9] foram os primeiros a definir e trabalhar em domínios estratificados. Grosso modo, estes são uma coleção de domínios disjuntos, cada um tendo sua própria dinâmica; mas não se exige que seus domínios sejam proximamente suaves e nem wedged. Estes termos foram introduzidos por P. Wolenski e R. Barnard em[10]. Primeiramente, estabeleceremos condições Hamiltonianos para caracterizar invariância fraca e forte para sistemas não Lipschitz em domínios estratificados. Depois, estudamos condições Hamiltonianas para sistemas fracamente e fortemente decrescentes e apresentamos condições que garantem a estabilidade assintótica global para uma dinâmica estratificada e finalmente apresentamos o problema tipo Mayer em domínios estratificados em que mostramos que a função valor e a única solução semicontínua inferior de uma generalização adequada da clássica equação Hamilton-Jacobi-Bellman, para a dinâmica estratificada / Abstract: In this work will characterize dynamical systems in the form of the so-called strati ed domain. Bressan and Hong [9] were the rst to de ne and work in strati ed domains. Roughly speaking, these are a collection of disjoint domains, each having its own dynamics; but not requiring that their domains are proximally smooth and not wedged. These terms were introduced by P. Wolenski and R. Barnard in [10]. At rst, we will establish Hamiltonian conditions to characterize weak and strong invariance for systems non-Lipschitz in strati ed domains. Secondly, we study the Hamiltonian conditions for systems weakly and strongly de- creasing and present conditions that guarantee global asymptotic stability for a strati ed dynamics and nally we present the problem Mayer type in strati ed domains where we show that the value function is the unique lower semicontinuous solution of an appropriate generalization of the classical Hamilton-Jacobi-Bellman equation for strati ed dynamics / Mestre

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