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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.
21

Ideal Structure of Rings of Analytic Functions with non-Archimedean Metrics

Bruno, Nicholas January 2021 (has links)
No description available.
22

Strong conceptual completeness and various stability theoretic results in continuous model theory

Albert, Jean-Martin January 2010 (has links)
<p>In this thesis we prove a strong conceptual completeness result for first-order continuous logic. Strong conceptual completeness was proved in 1987 by Michael Makkai for classical first-order logic, and states that it is possible to recover a first-order theory T by looking at functors originating from the category Mod(T) of its models. </p> <p> We then give a brief account of simple theories in continuous logic, and give a proof that the characterization of simple theories using dividing holds in continuous structures. These results are a specialization of well established results for thick cats which appear in [Ben03b] and in [Ben03a].</p> <p> Finally, we turn to the study of non-archimedean Banach spaces over non-trivially valued fields. We give a natural language and axioms to describe them, and show that they admit quantifier elimination, and are N0-stable. We also show that the theory of non-archimedean Banach spaces has only one N 1-saturated model in any cardinality. </p> / Thesis / Doctor of Philosophy (PhD)
23

Densités de copules archimédiennes hiérarchiques

Pham, David 04 1900 (has links)
Les copulas archimédiennes hiérarchiques ont récemment gagné en intérêt puisqu’elles généralisent la famille de copules archimédiennes, car elles introduisent une asymétrie partielle. Des algorithmes d’échantillonnages et des méthodes ont largement été développés pour de telles copules. Néanmoins, concernant l’estimation par maximum de vraisemblance et les tests d’adéquations, il est important d’avoir à disposition la densité de ces variables aléatoires. Ce travail remplie ce manque. Après une courte introduction aux copules et aux copules archimédiennes hiérarchiques, une équation générale sur les dérivées des noeuds et générateurs internes apparaissant dans la densité des copules archimédiennes hiérarchique. sera dérivée. Il en suit une formule tractable pour la densité des copules archimédiennes hiérarchiques. Des exemples incluant les familles archimédiennes usuelles ainsi que leur transformations sont présentés. De plus, une méthode numérique efficiente pour évaluer le logarithme des densités est présentée. / Nested Archimedean copulas recently gained interest since they generalize the well-known class of Archimedean copulas to allow for partial asymmetry. Sampling algorithms and strategies have been well investigated for nested Archimedean copulas. However, for likelihood based inference such as estimation or goodness-of-fit testing it is important to have the density. The present work fills this gap. After a short introduction on copula and nested Archimedean copulas, a general formula for the derivatives of the nodes and inner generators appearing in nested Archimedean copulas is developed. This leads to a tractable formula for the density of nested Archimedean copulas. Various examples including famous Archimedean families and transformations of such are given. Furthermore, a numerically efficient way to evaluate the log-density is presented.
24

Densités de copules archimédiennes hiérarchiques

Pham, David 04 1900 (has links)
Les copulas archimédiennes hiérarchiques ont récemment gagné en intérêt puisqu’elles généralisent la famille de copules archimédiennes, car elles introduisent une asymétrie partielle. Des algorithmes d’échantillonnages et des méthodes ont largement été développés pour de telles copules. Néanmoins, concernant l’estimation par maximum de vraisemblance et les tests d’adéquations, il est important d’avoir à disposition la densité de ces variables aléatoires. Ce travail remplie ce manque. Après une courte introduction aux copules et aux copules archimédiennes hiérarchiques, une équation générale sur les dérivées des noeuds et générateurs internes apparaissant dans la densité des copules archimédiennes hiérarchique. sera dérivée. Il en suit une formule tractable pour la densité des copules archimédiennes hiérarchiques. Des exemples incluant les familles archimédiennes usuelles ainsi que leur transformations sont présentés. De plus, une méthode numérique efficiente pour évaluer le logarithme des densités est présentée. / Nested Archimedean copulas recently gained interest since they generalize the well-known class of Archimedean copulas to allow for partial asymmetry. Sampling algorithms and strategies have been well investigated for nested Archimedean copulas. However, for likelihood based inference such as estimation or goodness-of-fit testing it is important to have the density. The present work fills this gap. After a short introduction on copula and nested Archimedean copulas, a general formula for the derivatives of the nodes and inner generators appearing in nested Archimedean copulas is developed. This leads to a tractable formula for the density of nested Archimedean copulas. Various examples including famous Archimedean families and transformations of such are given. Furthermore, a numerically efficient way to evaluate the log-density is presented.
25

Design and Testing of a Motion Controlled Gait Enhancing Mobile Shoe (GEMS) for Rehabilitation

Handzic, Ismet 01 January 2011 (has links)
Persons suffering central nervous system damage, such as a stroke, coma patients, or individuals that have suffered damage to the spinal cord, brainstem, cerebellum, and motor cortex, sometimes develop an asymmetric walking pattern where one leg does not fully swing backward. This uneven gait hinders these individuals in properly and efficiently moving through everyday life. Previous research in humans and various animals has introduced a split belt treadmill to analyze possible rehabilitation, which can recreate a correct gait pattern by altering the speed of each track. Gait adaptation was achieved by having the split belt treadmill move each leg at a different velocity relative to the ground and thus forcing a symmetric gait. Test subjects‟ gait would adapt to the speeds and a normal gait pattern could be conditioned while on the split belt treadmill. However, after short trials, individuals were unable to neurologically store these feed-forward walking patterns once walking over ground. Also, test subjects would have difficulty adapting their learned walking gait over different walking environments. The gait enhancing mobile shoe (GEMS) makes it possible to adjust an asymmetric walking gait so that both legs move at a relatively symmetric speed over ground. It alters the wearers walking gait by forcing each foot backwards during the stance phase, operating solely by mechanical motion, transferring the wearer‟s downward force into a horizontal backwards motion. Recreating the split belt treadmill effect over ground by using the GEMS will potentially enable me to test the long term effects of a corrected gait, which is impossible using a split belt treadmill. A previous prototype of the GEMS [1] successfully generated a split belt treadmill walking pattern, but had various drawbacks, such as variable motion from step to step. My new design of this rehabilitation shoe promises to alter the user‟s gait as a split belt treadmill does, and to be mechanically stable operating without any external power sources. I designed and constructed a new motion controlled gait enhancing mobile shoe that improves the previous version‟s drawbacks. While mimicking the asymmetric gait motion experienced on a split-belt treadmill, this version of the GEMS has motion that is continuous, smooth, and regulated with on-board electronics. An interesting aspect of this new design is the Archimedean spiral wheel shape that redirects the wearer‟s downward force into a horizontal backward motion. The design is passive and does not utilize any motors and actuators. Its motion is only regulated by a small magnetic pthesis brake. Initial tests show the shoe operates as desired, but further experimentation is needed to evaluate the long-term after-effects.
26

[en] JOINT MODELING OF FIXED INTEREST RATES LOG-RETURNS BASED ON TAIL DEPENDENCE MEASURES / [pt] MODELAGEM DA DISTRIBUIÇÃO CONJUNTA DOS LOG-RETORNOS DE TAXAS DE JUROS PRÉ-FIXADAS A PARTIR DE MEDIDAS DE DEPENDÊNCIA DE CAUDA

ALDO FERREIRA DA SILVA 27 February 2009 (has links)
[pt] A representação e interpretação claras da estrutura de dependência presente em vetores aleatórios, em particular em vetores bivariados, podem ser feitas com o uso do conceito de cópulas. Na análise bivariada, os coeficientes de dependência homogênea e heterogênea de cauda têm por objetivo estudar uma medida de dependência quando as variáveis assumem valores extre- mos. Obtemos as expressões dos coeficientes de dependência heterogênea de cauda a partir da função de distribuição acumulada condicional e apresen- tamos a demonstração de que os coeficientes de dependência homogênea de cauda de uma distribuição normal assimétrica são iguais a zero. Com o uso do conceito de cópulas e de dependência de cauda total, estudamos a estru- tura de dependência entre as seguintes variáveis: (i) log-retornos das taxas, interpoladas, para a estrutura a termo pré-fixada de 1 ano e de 2 anos; (ii) log-retorno das taxas para a estrutura a termo pré-fixada de 1 (um) ano e log-retorno do índice do Ibovespa; e (iii) log-retorno das taxas para a estru- tura a termo pré-fixada de 1 (um) ano e log-retorno da expectativa da taxa PTAX, 6 meses a frente. / [en] Using the concepts of copula we can represent and interpret the dependence structure presented in random vectors with clarity, particularly in bivariate vectors. In bivariate analysis, the role of both heterogeneous tail-dependence coefficient and homogenous tail- dependence coefficient are to study a measure of dependence when variables reach extreme values. We find expressions for the heterogeneous tail-dependence coefficients from the conditional cumulative distribution function and prove that the homoge- neous tail-dependence coefficients of a skewed normal distribution are equal to zero. Using the concepts of copula and the total tail dependence, we study the dependence structure between the following variables: (i) log- return of interpolated rates for the 1-year and 2-year fixed term structure; (ii) log-return of interpolated rate for the 1-year and log- return for the Bo- vespa index; e (iii) log-return of interpolated rate for the 1-year fixed term structure and log-return of expected PTAX, 6 months ahead.
27

Etude expérimentale et optimisation des performances hydrauliques des vis d'Archimède utilisées dans les micro centrales hydroélectriques / Experimental study and performance optimization of Archimedean screw turbine used in micro hydroelectric plants

Dellinger, Guilhem 10 December 2015 (has links)
Le potentiel de production d'hydroélectricité à l'aide de micro centrales hydroélectriques est sous-exploité en Europe. L'exploitation de petites chutes d'eau, à l'aide des vis d'Archimède, est un moyen de production d'énergie renouvelable récent et en voie de développement. Cette thèse étudie les performances hydrauliques de ce type de turbine. Une première partie du travail a porté sur la mise en place d'un dispositif expérimental, à échelle réduite, permettant de tester pour des conditions hydrauliques et des paramètres géométriques variés les performances hydrauliques d'une vis d'Archimède. Un modèle théorique semi-analytique permettant de déterminer les performances de la vis a été développé puis validé à l'aide des résultats expérimentaux. Les écoulements complexes au sein de cette turbine sont étudiés par le biais d'une modélisation numérique 3D instationnaire, validée expérimentalement. La compréhension de la structure de l'écoulement a alors permis de développer un nouveau modèle théorique permettant de déterminer avec plus de précision le débit de fuite qui est à l'origine d'une perte significative de rendement. Ces résultats permettent d'envisager l'implémentation d'un modèle de dimensionnement industriel. / The potential for hydropower generation using micro-hydro plants is still under exploited in Europe. The Archimede Screw Generators are a growing technology convenient for low-head hydraulic sites. This thesis studies the hydraulic performance of this turbine. The first part of thiswork presents an experimental device using a laboratory screw scale. This device allows to test screw performance for various hydraulic conditions and geometrical parameters. A theoretical model predicting the screw performance has then been developed and validated with experimental results.The complex flows occurring within the screw are studied thanks to 3D and unsteady numerical simulations. The numerical results are validated experimentally. The insights provided on the flow structure permit to develop a new leakage model. These leakages are a major source of efficiency loss. Eventually, all these results will allow the implementation of an industrial dimensioning model.
28

Números p-ádicos

Gusmão, Ítalo Moraes de Melo 25 August 2015 (has links)
Submitted by ANA KARLA PEREIRA RODRIGUES (anakarla_@hotmail.com) on 2017-08-29T16:07:28Z No. of bitstreams: 1 arquivototal.pdf: 945033 bytes, checksum: cab32f76c5a55b0c6400063ed6b40ff6 (MD5) / Approved for entry into archive by Fernando Souza (fernandoafsou@gmail.com) on 2017-08-29T16:11:36Z (GMT) No. of bitstreams: 1 arquivototal.pdf: 945033 bytes, checksum: cab32f76c5a55b0c6400063ed6b40ff6 (MD5) / Made available in DSpace on 2017-08-29T16:11:36Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 945033 bytes, checksum: cab32f76c5a55b0c6400063ed6b40ff6 (MD5) Previous issue date: 2015-08-25 / We introduce and de ne the p-adics integer numbers as a result of a search for solutions, for a congruences system that derives from a variable polynomial equation with rational coe cients. We evidence that the p-adic integers set is strictly larger than the integers. We present a criterion so that a rational that holds a correspondent in a p-adic integers set. We search for the possibility to represent irrational and complex numbers as p-adics integers. Algebraically, the p-adic integers set will be an integral domain and, from this, we search for the construction of p-adic integers quotient eld so that shall form the p-adic rationals eld, from a purely algebraically point of view. In the second part, we will expose the bases for the construction of a norm that's di erent from the usual, establishing so a new metric in the rational numbers set and the construction of a non-archimedian eld. / Apresentamos e de nimos os números inteiros p-ádicos como o resultado de uma busca por soluções, para um sistema de congruências, que parte de uma equação polinomial de uma variável, com coe cientes racionais. Constatamos que o conjunto dos inteiros p-ádicos é estritamente maior que os inteiros. Mostramos um critério para que um racional possua um correspondente num conjunto de inteiros p-ádicos. Buscamos a possibilidade de representarmos números irracionais e números complexos como inteiros p-ádicos. Algebricamente, o conjunto dos inteiros p-ádicos será um domínio de integridade e, partindo disto, buscamos a construção de um corpo de frações dos inteiros p-ádicos, que formarão, assim, o corpo dos racionais p-ádicos, de um ponto de vista puramente algébrico. Na segunda parte, vamos expor os fundamentos para a construção de uma norma diferente da habitual, estabelecendo assim uma nova métrica, no conjunto dos números racionais, e a construção de um corpo não-arquimediano.
29

A study of skeleta in non-Archimedean geometry / Une étude des squelettes en géométrie non Archimédienne

Welliaveetil, John 30 June 2015 (has links)
Cette thèse s'appuie sur et reflète l'interaction entre la théorie des modèles et la géométrie de Berkovich. En utilisant les méthodes de Hrushovski et Loeser, nous montrerons que plusieurs phénomènes topologiques concernant des analytifications de variétés sont contrôlés par certains complexes simpliciaux contenus dans les analytifications. Ce travail comporte les résultats suivants. Soit $k$ un corps algébriquement clos et complet pour une valuation non-archimédienne non-triviale à valeurs réelles. 1) Soit $\phi : C' \to C$ un morphisme fini entre deux courbes projectives, lisses et irréductibles. Le morphisme $\phi$ induit un morphisme $\phi^{an} : C'^{an} \to C^{an}$ entre les deux analytifications. Nous construisons une paire de rétractions par déformations qui sont compatible pour le morphisme $\phi^{an}$. Les images des déformations $\Upsilon_{C'^{an}}$, $\Upsilon_{C^{an}$ sont des sous-espaces fermés de $C'^{an}$ and $C^{an}$ et homéomorphes à des graphes finis. Ce type de sous-espace est appelé \emph{squelette}. En outre, les espaces analytiques $C'^{an} \smallsetminus \Upsilon_{C'^{an}}$ et $C^{an} \smallsetminus \Upsilon_{C^{an}}$ se décomposent en une union disjointe de copies de disques unités de Berkovich. Un squelette $\Upsilon \subset C^{an}$ peut-être décomposé en un ensemble des sommets et un ensemble d'arêtes et on peut définir son genre $g(\Upsilon)$.Nous montrons que $g(\Upsilon)$ est un invariant bien défini de la courbe $C$. On appelle cet invariant $g^{an}(C)$. Le morphisme $\phi^{an}$ induira un morphisme $\Upsilon_{C'^{an}} \to \Upsilon_{C^{an}}$ entre les deux squelettes. Nous montrons que le genre du squelette $\Upsilon_{C'^{an}}$ peut être calculé en utilisant certains invariants associés aux points de $\Upsilon_{C^{an}}$. 2) Soit $\phi$ un endomorphisme fini de $\mathbb{P}^1_k$. Soit $x \in \mathbb{P}^1_k(k)$ et $f(x)$ le rayon de la plus grande boule de Berkovich de centre $x$, sur laquelle le morphisme $\phi^{an}$ est une fibration topologique. Nous voyons que la fonction $f : \mathbb{P}_k^1(k) \to \mathbb{R}_{\geq 0}$ est contrôlée par un graphe fini et non-vide contenu dans $\mathbb{P}^{1,an}_k$. Nous montrons que ce résultat peut être généralisé au cas d'un morphisme fini $\phi : V' \to V$ entre deux variétés intégrales, projectives avec $V$ normale. / This thesis is a reflection of the interaction between Berkovich geometry and model theory. Using the results of Hrushovski and Loeser, we show that several interesting topological phenomena that concern the analytifications of varieties are governed by certain finite simplicial complexes embedded in them. Our work consists of the following two sets of results. Let k be an algebraically closed non-Archimedean non trivially real valued field which is complete with respect to its valuation. 1) Let $\phi : C' \to C$ be a finite morphism between smooth projective irreducible $k$-curves.The morphism $\phi$ induces a morphism $\phi^{an} : C'^{an} \to C^{an}$ between the Berkovich analytifications of the curves. We construct a pair of deformation retractions of $C'^{an}$ and $C^{an}$ which are compatible with the morphism $\phi^{\mathrm{an}}$ andwhose images $\Upsilon_{C'^{an}}$, $\Upsilon_{C^{an}}$ are closed subspaces of $C'^{an}$, $C^{an}$ that are homeomorphic to finite metric graphs. We refer to such closed subspaces as skeleta.In addition, the subspaces $\Upsilon_{C'^{an}}$ and $\Upsilon_{C^{an}}$ are such that their complements in their respective analytifications decompose into the disjoint union of isomorphic copies of Berkovich open balls. The skeleta can be seen as the union of vertices and edges, thus allowing us to define their genus. The genus of a skeleton in a curve $C$ is in fact an invariant of the curve which we call $g^{an}(C)$. The pair of compatible deformation retractions forces the morphism $\phi^{an}$ to restrict to a map $\Upsilon_{C'^{an}} \to \Upsilon_{C^{an}}$. We study how the genus of $\Upsilon_{C'^{an}}$ can be calculated using the morphism $\phi^{an}_{|\Upsilon_{C'^{an}}$ and invariants defined on $\Upsilon_{C^{an}}$. 2) Let $\phi$ be a finite endomorphism of $\mathbb{P}^1_k$. Given a closed point $x \in \mathbb{P}^1_k$, we are interested in the radius $f(x)$ of the largest Berkovich open ball centered at $x$ over which the morphism $\phi^{\mathrm{an}}$ is a topological fibration. Interestingly, the function $f : \mathbb{P}_k^1(k) \to \mathbb{R}_{\geq 0}$ admits a strong tameness property in that it is controlled by a non-empty finite graph contained in $\mathbb{P}^{1,an}_k$. We show that this result can be generalized to the case of finite morphisms $\phi : V' \to V$ between integral projective $k$-varieties where $V$ is normal.
30

Parallel Coordinates Diagram Implementation in 3D Geometry

Suma, Christopher G. January 2018 (has links)
No description available.

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