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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.
121

Using Combined Integration Algorithms for Real-time Simulation of Continuous Systems

Harbor, Larry Keith 01 January 1988 (has links) (PDF)
At many American colleges and universities, efforts to enhance the retention of a diverse group of students have become a priority. This study represents part of this effort at the University of Central Florida, a large public suburban state university in the South. Specifically, this investigation evaluated Pegasus '95 and the Academic Mentoring Program offered in the Summer and Fall Semesters of 1995 to specially-admitted students who fell short of regular admissions requirements. During the summer, Pegasus '95 provided testing, orientation, guided course work, study skills workshops, and mentoring, both individually and in the context of cohesive socialization groups of approximately 15 students each. In the Fall 1995 Semester, students were highly encouraged to participate in one-on-one mentoring in the Academic Mentoring Program (AMP) available through the Student Academic Resource Center (SARC), a university-based office which provides a variety of academic assistance services. A multiple regression analysis was conducted using the following independent predictor variables: gender, SAT/ACT scores, Pegasus participation, use of the AMP in the Fall 1995 semester, four summary scores from the College Student Inventory (CSI), and eight scaled scores from the Noncognitive Questionnaire (NCQ). Dependent variables were individual student GPA in the Summer and Fall 1995 semesters, cumulative GPA after two semesters, and enrolled credit hours into the Spring 1996 academic term. Overall, it was expected that a combination of predictor variables, including both traditional cognitive factors (SAT/ACT scores and high school GPA) and noncognitive factors (NCQ scores and CSI scores, Pegasus participation, and mentoring by the SARC) would significantly predict GP A and retention. The study found that a regression equation including gender, high school GPA, overall SAT scores and the eight NCQ scale scores significantly predicted Fall 1995 and cumulative GPA after two semesters but not Summer 1995 GPA or credit hours enrolled in Spring 1996. Attendance at Pegasus meetings was also shown to be significantly and positively associated with Fall 1995 GPA and cumulative GPA after two semesters but not of Summer 1995 GPA or credit hours enrolled in Spring 1996. Gender, high school GP A, the ACT score and the CSI Dropout Proneness scale significantly predicted credit hours enrolled in Spring 1996, as did use of the AMP program provided by the SARC. Of particular interest was the finding that including noncognitive factors in significant equations led to a greater explanation of the variance than could be obtained with any of the traditional cognitive measurements alone, suggesting that with academically disadvantaged students noncognitive measures must be considered in predicting who can succeed and persist in college.
122

Invariants d’Iwasawa dans les extensions de Lie p-adiques des corps de nombres / Iwasawa invariants in p-adic Lie extensions of number fiels

Perbet, Guillaume 06 December 2011 (has links)
Le but de cette thèse est l'étude des invariants d'Iwasawa attachés aux p-groupes des classes généralisés dans les extensions de Lie p-adiques de corps de nombres.Ces invariants ont été introduits par Iwasawa pour les Zp-extensions. Les travaux de Venjakob sur la structure des modules sur l'algèbre d'Iwasawa d'un groupe de Lie p-adique ont permis d'en généraliser la définition à la théorie non-commutative. Par des techniques de descente et une étude algébrique fine de la structure des modules d'Iwasawa sur un groupe non-commutatif, on dégage des formules asymptotiques pour les p-groupes des classes généralisés le long d'une extension de corps de nombres de groupe de Galois p-valué. Ces formules ont pour paramètres les invariants d'Iwasawa de l'extension. Elles sont rendues plus précises dans le cas des Zp-extensions, où on remarque qu'un défaut de descente doit être pris en compte et est d'impact non négligeable sur le résultat final. Ces résultats asymptotiques sont ensuite exploités à l'aide de la théorie du miroir. Ceci conduit à des formules de dualité entre ramification et décomposition concernant les invariants d'Iwasawa / This thesis aim at exploring Iwasawa invariants attached to generalized p-class groups in p-adic Lie extensions of number fields. These invariants where introduced by Iwasawa for Zp-extensions. In his work on the structure of modules over the Iwasawa algebra of a p-adic Lie group, Venjakob extends the definition to the non commutative theory. Using descent techniques, along with a fine algebraic study of Iwasawa's modules structure over a non commutative group, we obtain asymptotic formulas for generalized p-class groups in a tower of number fields, with a p-valued group as Galois group. These formulas have Iwasawa invariants as parameters. They become more precise for Zp-extensions, where a significant descent default is involved. These asymptotic results are exploited thanks to reflexion theory. This leads to duality formulas between ramification and decomposition for Iwasawa invariants
123

Nástroje pro tvorbu vzorců organických sloučenin a možnosti jejich využití ve výuce chemie / Tools for Creating Organic Compound Formulas and Possibilities of their Use in Chemistry Education

Stárková, Dagmar January 2013 (has links)
The thesis explores suitability of software for drawing formulas in organic chemistry and its preparation in elementary and high schools. It uses both quantitative and qualitative research methods and notes that this kind of software could be a practical teaching aid if it was properly placed in the educational process. The thesis represents essential functions of these programs with respect to their technical demands. It also examines the current status of the use of software for drawing formulas from the teachers perspective in primary and secondary education. Presented is an overview of the functions of software for drawing formulas with regard to their use in organic chemistry. The findings of this research indicate that organic chemistry is the topic where the editors are most commonly used. It was also found that respondents use software for drawing formulas very rarely, especially to prepare for teaching, less in the school. In today's digital age, this condition cannnot be accepted. It is necessary to examine various options for the use of information and communication technologies and to promote their effective integration into chemistry education as many researches have shown.
124

Das fórmulas ao nome: bases para uma teoria da sexuação em Lacan / From formulas to naming: conceptual bases for a sexuation theory in Lacan

Ambra, Pedro Eduardo Silva 26 October 2017 (has links)
A presente tese tem por objetivo a explicitação de bases conceituais que sustentem uma nova leitura da teoria da sexuação. O texto busca investigar a origem e extrair consequências da máxima o ser sexual só se autoriza de si mesmo e de alguns outros, enunciada por Lacan no seminário Os não-bestas erram, num exercício de redescrição das fórmulas da sexuação a partir de um dizer. Visando sublinhar a dimensão processual da sexuação, elegeu-se o conceito de identificação como método e realizouse um levantamento de suas incidências junto aos registros real, simbólico e imaginário ao longo do ensino de Lacan. No primeiro capítulo, discutiu-se a influência de Marcel Proust na concepção lacaniana que liga a autorização sexuada ao grupo e o paralelo entre a sexuação e a autorização do psicanalista. Buscou-se, junto a modalidades de luta por reconhecimento social e político de gêneros não inteligíveis, um modelo de grupo que Lacan precisa como aquele de um real recentemente emergido. No segundo capítulo, retraçaram-se as origens das noções de significante (na ideia de constelação simbólica), grande Outro (descrito inicialmente como grandes Outros) e lei simbólica (e sua indissociável relação com a norma em Lévi-Strauss), buscando demonstrar de que forma a alteridade simbólica que localiza a posição do sujeito sexuado é plural e baseia-se na variabilidade dos elementos num dado sistema estrutural. O último capítulo buscou apresentar, tanto em Freud como em Lacan, o papel fundamental dos semelhantes no processo de assunção sexual, bem como discutiu a autorização em termos de uma precipitação presente tanto no estádio do espelho quanto no momento de concluir do tempo lógico. Por fim, uma discussão relativa à noção de sinthoma demonstrou a centralidade do ato de nomeação enquanto instância que enoda os três registros da sexuação / This thesis aims to detail the conceptual bases for a new reading of Lacans sexuation theory. We intent to investigate the genesis and consequences of the proposition The sexed being is only authorized by him/herself and by some others, uttered by Lacan on his seminar Les non-dupes errant, as he describes the formulas of sexuation in terms of a saying. In order to underscore the sexuations processual dimension, the concept of identification was turned into a methodological tool as we proceed an analysis of its incidences among the registers of the real, symbolic and imaginary in Lacans teaching. On our first chapter, weve discussed the sexuation and its parallel with the analysts authorization as well as Marcel Prousts influence on the lacaninan relation between sexed authorization and the question of the group. Gender related social and political struggles were taken as a model of the lacanian notion of group as an real recently emerged. On our second chapter, weve explored the origins of the notions of signifier (from the idea of symbolic constellation), big Other (initially described as big Others) and symbolic law (and its inseparable relation with the norm in Lévi-Strauss), to indicate how the symbolic alterity that locates the sexed subjects position is plural and based on the elements variability at one given structural system. The last chapter presents the fundamental role of the neighbors on the sexual assumptions process and discusses the authorization in terms of an anticipation found in both mirror stage and the logical times moment of concluding. Lastly, an analysis of the notion of sinthome has shown the centrality of the act of naming as an instance that knots the three registers of the sexuation
125

Revisão sistemática de metodologias de financiamento em sistemas universais

Lobato, Marcos Antônio de Oliveira January 2016 (has links)
A distribuição de recursos financeiros é um desafio para a gestão pública de saúde. Este estudo revisa sistematicamente os critérios de alocação de recursos financeiros públicos dentro de territórios políticos administrativos para serviços e ações de saúde com acesso universal de populações em áreas geográficas definidas em documentos publicados sem restrição de data inicial até 2015 em português, inglês, espanhol e italiano em sites acadêmicos, Organização Mundial da Saúde e Banco Mundial. Foram encontradas 37 publicações abrangendo 53 metodologias, a maioria referente a países europeus de alto desenvolvimento humano e língua inglesa. A Inglaterra foi o país pioneiro e desenvolveu 6 metodologias de alocação. A maioria das metodologias inclui critérios socioeconômicos, demográficos e epidemiológicos. Critérios espacial, oferta de serviços e/ou capacidade instalada, fonte própria de financiamento, custo de prestação de serviços e ações, utilização de serviços de saúde e fluxos inter-regionais ocorreram quase que exclusivamente em países de alto desenvolvimento econômico e social. Esses resultados sugerem que a minoria dos países utiliza metodologias padronizadas para alocar recursos financeiros entre regiões do seu território. A grande maioria das metodologias baseia-se na determinação social da saúde. Existe uma tendência de desenvolvimento de modelos mais complexos com a inclusão de variáveis que necessitam de um sistema de informação mais complexo, raramente disponíveis. / The distribution of financial resources is a challenge for public health management. This study systematically reviews the criteria for allocating public financial resources within political administrative territories for health services and actions with universal access of populations in defined geographical areas in published documents without restriction of initial date up to 2015 in Portuguese, English, Spanish and Italian On academic sites World Health Organization and the World Bank. We found 37 publications covering 53 methodologies, most of which refer to European countries with high human development and English language. England pioneered and developed 6 allocation methodologies. Most methodologies include socioeconomic, demographic and epidemiological criteria. Spatial criteria, supply of services and / or installed capacity, own source of financing, cost of services and actions, use of health services and interregional flows occurred almost exclusively in countries with high economic and social development. These results suggest that the minority of countries use standardized methodologies to allocate financial resources between regions of their territory. The vast majority of methodologies are based on the social determination of health. There is a tendency to develop more complex models with the inclusion of variables that require a more complex information system, rarely available.
126

Approximation par éléments finis conformes et non conformes enrichis / Approximation by enriched conforming and nonconforming finite elements

Zaim, Yassine 11 September 2017 (has links)
L’enrichissement des éléments finis standard est un outil performant pour améliorer la qualité d’approximation. L’idée principale de cette approche est d’ajouter aux fonctions de base un ensemble de fonctions censées améliorer la qualité des solutions approchées. Le choix de ces dernières est crucial et est en grande partie basé sur la connaissance a priori de quelques informations telles que les caractéristiques de la solution, de la géométrie du problème à résoudre, etc. L’efficacité de cette approche pour résoudre une équation aux dérivées partielles dans un maillage fixe, sans avoir recours au raffinement, a été prouvée dans de nombreuses applications dans la littérature. La clé de son succès repose principalement sur le bon choix des fonctions de base et plus particulièrement celui des fonctions d’enrichissement. Une question importante se pose alors : quelles conditions faut-il imposer sur les fonctions d’enrichissement afin qu’elles génèrent des éléments finis bien définis ?Dans cette thèse sont abordés différents aspects d’une approche générale d’enrichissement d’éléments finis. Notre première contribution porte principalement sur l’enrichissement de l’élément fini du type Q_1. Par contre, notre seconde contribution, certainement la plus importante, met l’accent sur une approche plus générale pour enrichir n’importe quel élément fini qu’il soit P_k, Q_k ou autres, conformes ou non conformes. Cette approche a conduit à l’obtention des versions enrichies de l’élément de Han, l’élément de Rannacher-Turek et l’élément de Wilson, qui font maintenant partie des codes d’éléments finis les plus couramment utilisés en milieu industriel. Pour établir ces extensions, nous avons eu recours à l’élaboration de nouvelles formules de quadrature multidimensionnelles appropriées généralisant les formules classiques bien connues en dimension 1, dites du “point milieu,” des “trapèzes” et de leurs versions perturbées, ainsi que la formule de Simpson. Elles peuvent être vues comme des extensions naturelles de ces formules en dimension supérieure. Ces dernières, en plus de leurs tests numériques implémentés sous MATLAB, version R2016a, ont fait l’objet de notre troisième contribution. Nous mettons particulièrement l’accent sur la détermination explicite des meilleures constantes possibles apparaissant dans les estimations d’erreur pour ces formules d’intégration. Enfin, dans la quatrième contribution nous testons notre approche pour résoudre numériquement le problème d’élasticité linéaire à l’aide d’un maillage rectangulaire. Nous effectuons l’analyse numérique aussi bien l’analyse de l’erreur d’approximation et résultats de convergence que l’analyse de l’erreur de consistance. Nous montrons également comment cette dernière peut être établie à n’importe quel ordre, généralisant ainsi certains travaux menés dans le domaine. Nous réalisons la mise en œuvre de la méthode et donnons quelques résultats numériques établis à l’aide de la bibliothèque libre d’éléments finis GetFEM++, version 5.0. Le but principal de cette partie sert aussi bien à la validation de nos résultats théoriques, qu’à montrer comment notre approche permet d’élargir la gamme de choix des fonctions d’enrichissement. En outre, elle permet de montrer comment cette large gamme de choix peut aider à avoir des solutions optimales et également à améliorer la validité et la qualité de l’espace d’approximation enrichie. / The enrichment of standard finite elements is a powerful tool to improve the quality of approximation. The main idea of this approach is to incorporate some additional functions on the set of basis functions. These latter are requested to improve the accuracy of the approximate solution. Their best choice is crucial and is based on the knowledge of some a priori information, such as the characteristics of the solution, the geometry of the problem to be solved, etc. The efficiency of such an approach for finding numerical solutions of partial differential equations using a fixed mesh, without recourse to refinement, was proved in numerous applications in the literature. However, the key to its success lies mainly on the best choice of the basis functions, and more particularly those of enrichment functions.An important question then arises: How to suitably choose them, in such a way that they generate a well-defined finite element ?In this thesis, we present a general approach that enables an enrichment of the finite element approximation. This was the subject of our first contribution, which was devoted to the enrichment of the classical Q_1 element, as a first step. As a second step, in our second contribution, we have developed a more general framework for enriching any finite element either P_k, Q_k or others, conforming or nonconforming. As an illustration of how to use this framework to build new enriched finite elements, we have introduced the extensions of some well-known nonconforming finite elements, notably, Han element, Rannacher-Turek element and Wilson element, which are now part of the main code of finite element methods. To establish these extensions, we have introduced a new family of multivariate versions of the classical trapezoidal, midpoint and Simpson rules. These latter, in addition to their numerical tests under MATLAB, version R2016a, have been the subject of our third contribution. They may be viewed as an extension of the well-known trapezoidal, midpoint and Simpson’s one-dimensional rules to higher dimensions. We particularly pay attention to the explicit expressions of the best possible constants appearing in the error estimates for these cubatute formulas. Finally, in the fourth contribution we apply our approach to numerically solving the linear elasticity problem based on a rectangular mesh. We carry out the numerical analysis of the approximation error and also for the consistency error, and show how the latter can be established to any order. This constitutes a generalization of some work already done in the field. In addition to our theoretical results, we have also made some numerical tests, which were achieved by using the GetFEM++ library, version 5.0. The aim of this contribution was not only to confirm our theoretical predictions, but also to show how the new developed framework allows us to expand the range of choices of enrichment functions. Furthermore, we have shown how this wide choices range can help us to improve some approximation properties and to get the optimal solutions for the particular problem of elasticity.
127

On the pricing equations of some path-dependent options

Eriksson, Jonatan January 2006 (has links)
<p>This thesis consists of four papers and a summary. The common topic of the included papers are the pricing equations of path-dependent options. Various properties of barrier options and American options are studied, such as convexity of option prices, the size of the continuation region in American option pricing and pricing formulas for turbo warrants. In Paper I we study the effect of model misspecification on barrier option pricing. It turns out that, as in the case of ordinary European and American options, this is closely related to convexity properties of the option prices. We show that barrier option prices are convex under certain conditions on the contract function and on the relation between the risk-free rate of return and the dividend rate. In Paper II a new condition is given to ensure that the early exercise feature in American option pricing has a positive value. We give necessary and sufficient conditions for the American option price to coincide with the corresponding European option price in at least one diffusion model. In Paper III we study parabolic obstacle problems related to American option pricing and in particular the size of the non-coincidence set. The main result is that if the boundary of the set of points where the obstacle is a strict subsolution to the differential equation is C<sup>1</sup>-Dini in space and Lipschitz in time, there is a positive distance, which is uniform in space, between the boundary of this set and the boundary of the non-coincidence set. In Paper IV we derive explicit pricing formulas for turbo warrants under the classical Black-Scholes assumptions.</p>
128

On the pricing equations of some path-dependent options

Eriksson, Jonatan January 2006 (has links)
This thesis consists of four papers and a summary. The common topic of the included papers are the pricing equations of path-dependent options. Various properties of barrier options and American options are studied, such as convexity of option prices, the size of the continuation region in American option pricing and pricing formulas for turbo warrants. In Paper I we study the effect of model misspecification on barrier option pricing. It turns out that, as in the case of ordinary European and American options, this is closely related to convexity properties of the option prices. We show that barrier option prices are convex under certain conditions on the contract function and on the relation between the risk-free rate of return and the dividend rate. In Paper II a new condition is given to ensure that the early exercise feature in American option pricing has a positive value. We give necessary and sufficient conditions for the American option price to coincide with the corresponding European option price in at least one diffusion model. In Paper III we study parabolic obstacle problems related to American option pricing and in particular the size of the non-coincidence set. The main result is that if the boundary of the set of points where the obstacle is a strict subsolution to the differential equation is C1-Dini in space and Lipschitz in time, there is a positive distance, which is uniform in space, between the boundary of this set and the boundary of the non-coincidence set. In Paper IV we derive explicit pricing formulas for turbo warrants under the classical Black-Scholes assumptions.
129

The dynamics of the compression of a motor vehicle tyre constrained by the road.

Matsho, Stephens Kgalushi. January 2012 (has links)
M. Tech. : Mathematical Technology. / Attempts will be made to extend the elementary quarter-mass models (for instance Gillepse, 1992, [5]; Kiecke & Nielsen, 2000, [6] and Singiresu, 2004, [7]) of a motor vehicle suspension system to include the radial vibrations of a rubber tyre in the model. Tangential vibrations of the tyre surface were investigated by Bekker (2009, [8]) and the possible incorporation of such vibrations into a suspension model invites the possibility of future study.
130

Multisymplectic integration : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Mathematical Physics at Massey University, Palmerston North, New Zealand

Ryland, Brett Nicholas January 2007 (has links)
Multisymplectic integration is a relatively new addition to the field of geometric integration, which is a modern approach to the numerical integration of systems of differential equations. Multisymplectic integration is carried out by numerical integrators known as multisymplectic integrators, which preserve a discrete analogue of a multisymplectic conservation law. In recent years, it has been shown that various discretisations of a multi-Hamiltonian PDE satisfy a discrete analogue of a multisymplectic conservation law. In particular, discretisation in time and space by the popular symplectic Runge–Kutta methods has been shown to be multisymplectic. However, a multisymplectic integrator not only needs to satisfy a discrete multisymplectic conservation law, but it must also form a well-defined numerical method. One of the main questions considered in this thesis is that of when a multi-Hamiltonian PDE discretised by Runge–Kutta or partitioned Runge–Kutta methods gives rise to a well-defined multisymplectic integrator. In particular, multisymplectic integrators that are explicit are sought, since an integrator that is explicit will, in general, be well defined. The first class of discretisation methods that I consider are the popular symplectic Runge–Kutta methods. These have previously been shown to satisfy a discrete analogue of the multisymplectic conservation law. However, these previous studies typically fail to consider whether or not the system of equations resulting from such a discretisation is well defined. By considering the semi-discretisation and the full discretisation of a multi-Hamiltonian PDE by such methods, I show the following: • For Runge–Kutta (and for partitioned Runge–Kutta methods), the active variables in the spatial discretisation are the stage variables of the method, not the node variables (as is typical in the time integration of ODEs). • The equations resulting from a semi-discretisation with periodic boundary conditions are only well defined when both the number of stages in the Runge–Kutta method and the number of cells in the spatial discretisation are odd. For other types of boundary conditions, these equations are not well defined in general. • For a full discretisation, the numerical method appears to be well defined at first, but for some boundary conditions, the numerical method fails to accurately represent the PDE, while for other boundary conditions, the numerical method is highly implicit, ill-conditioned and impractical for all but the simplest of applications. An exception to this is the Preissman box scheme, whose simplicity avoids the difficulties of higher order methods. • For a multisymplectic integrator, boundary conditions are treated differently in time and in space. This breaks the symmetry between time and space that is inherent in multisymplectic geometry. The second class of discretisation methods that I consider are partitioned Runge– Kutta methods. Discretisation of a multi-Hamiltonian PDE by such methods has lead to the following two major results: 1. There is a simple set of conditions on the coefficients of a general partitioned Runge– Kutta method (which includes Runge–Kutta methods) such that a general multi- Hamiltonian PDE, discretised (either fully or partially) by such methods, satisfies a natural discrete analogue of the multisymplectic conservation law associated with that multi-Hamiltonian PDE. 2. I have defined a class of multi-Hamiltonian PDEs that, when discretised in space by a member of the Lobatto IIIA–IIIB class of partitioned Runge–Kutta methods, give rise to a system of explicit ODEs in time by means of a construction algorithm. These ODEs are well defined (since they are explicit), local, high order, multisymplectic and handle boundary conditions in a simple manner without the need for any extra requirements. Furthermore, by analysing the dispersion relation for these explicit ODEs, it is found that such spatial discretisations are stable. From these explicit ODEs in time, well-defined multisymplectic integrators can be constructed by applying an explicit discretisation in time that satisfies a fully discrete analogue of the semi-discrete multisymplectic conservation law satisfied by the ODEs. Three examples of explicit multisymplectic integrators are given for the nonlinear Schr¨odinger equation, whereby the explicit ODEs in time are discretised by the 2-stage Lobatto IIIA– IIIB, linear–nonlinear splitting and real–imaginary–nonlinear splitting methods. These are all shown to satisfy discrete analogues of the multisymplectic conservation law, however, only the discrete multisymplectic conservation laws satisfied by the first and third multisymplectic integrators are local. Since it is the stage variables that are active in a Runge–Kutta or partitioned Runge– Kutta discretisation in space of a multi-Hamiltonian PDE, the order of such a spatial discretisation is limited by the order of the stage variables. Moreover, the spatial discretisation contains an approximation of the spatial derivatives, and thus, the order of the spatial discretisation may be further limited by the order of this approximation. For the explicit ODEs resulting from an r-stage Lobatto IIIA–IIIB discretisation in space of an appropriate multi-Hamiltonian PDE, the order of this spatial discretisation is r - 1 for r = 10; this is conjectured to hold for higher values of r. For r = 3, I show that a modification to the initial conditions improves the order of this spatial discretisation. It is expected that a similar modification to the initial conditions will improve the order of such spatial discretisations for higher values of r.

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