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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.
31

Monodromie du problème de Cauchy ramifié et ramification autour d'un ensemble analytique

Camales, Renaud 27 June 2002 (has links) (PDF)
Dans la première partiede cette thèse, nous étudions la monodromie du problème de Cauchy ramifié pour un opérateur à caractéristiques multiples de multiplicité constante. Plus précisément, nous donnons une estimation du spectre de la monodromie. Notre méthode est basée sur le calcul de la monodromie de certains opérateurs intégro-différentiels. Dans la seconde partie, on étudie le problème de Cauchy pour certains opérateurs. Nous écrivons la solution sous forme intégrale puis nous étudions le prolongement analytique decette intégrale.
32

Spécialisation sur le cône tangent et équisingularité à la Whitney

Giles Flores, Arturo 30 September 2011 (has links) (PDF)
Cette thèse porte sur l'étude de la géométrie de l'espace de spécialisation φ : (X, 0) → (C, 0) d'un germe de singularité analytique complexe (X, 0) sur son cône tangent (CX,0 , 0) du point de vue de l'équisingularité à la Whitney. L'application φ nous donne une famille plate des germes avec section tel que pour chaque t =! 0 le germe φ−1 (t) est isomorphe à (X, 0) et la fibre spéciale est isomorphe au cône tangent. Le but est de établir des conditions sur les strates de la stratification de Whitney minimale de (X, 0) qui assurent l'équisingularité du germe et son cône tangent, generalisant ainsi le résultat de Lê et Teissier pour les hypersurfaces de C3 qui prouve que l'absence des tangentes exceptionnelles est suffisant. Dans ce travail on montre que cette condition est nécessaire et suffisante dans le cas général pour la strate de codimension zero. L'un des ingrédients clés dans la preuve est la théorie de la dépendance integrale sur des ideaux et des modules développé par Teissier, Lejeune, Gaffney, Kleiman, etc, qu'on rappelle au troisième chapitre et où l'on obtient des résultats spécifiques pour cette situation. Les deux premiers chapitres correspondent aux préliminaires, on commence par rappeller la modification de Nash et l'espace conormal d'un espace analytique plongé dans ses versions absolues et relatives à un morphisme et on donne une description explicite de la relation entre le conormal (Nash) relatif de φ : (X, 0) → (C, 0) et le conormal (Nash) de (X, 0). Dans le deuxième chapitre on définit le diagram normal/conormal, l'auréole du germe (X, 0), les cônes exceptionnelles, et on énonce les résultats principaux correspondant à l'équisingularité à la Whitney en incluant la caractérisation des conditions de Whitney en termes du diagramme normal/conormal.
33

Tests of Bivariate Stochastic Order

Liu, Yunfeng 28 September 2011 (has links)
The purpose of this thesis is to compare rank-based tests of bivariate stochastic order. Given two bivariate distributions $F$ and $G$, the general problem we are dealing with is to test $H_0: F=G$ against $H_1:F<G$, where $F$ and $G$ are independent continuous distributions on $\Re ^2$. (``$F<G$" means that $F(x)\leq G(x)~\forall x\in \Re^2$, and $\exists x\in \Re^2$ such that $F(x)< G(x)$.). In particular, we will analyze three analogues of the one-dimensional Mann-Whitney-Wilcoxon test in two dimensions. Two of the test statistics are new; we call them the Kendall and Spearman statistics. We will then show the asymptotic distributions and carry out empirical comparisons of the Kendall, Spearman and the third two-dimensional Mann-Whitney-Wilcoxon statistics.
34

Tests of Bivariate Stochastic Order

Liu, Yunfeng 28 September 2011 (has links)
The purpose of this thesis is to compare rank-based tests of bivariate stochastic order. Given two bivariate distributions $F$ and $G$, the general problem we are dealing with is to test $H_0: F=G$ against $H_1:F<G$, where $F$ and $G$ are independent continuous distributions on $\Re ^2$. (``$F<G$" means that $F(x)\leq G(x)~\forall x\in \Re^2$, and $\exists x\in \Re^2$ such that $F(x)< G(x)$.). In particular, we will analyze three analogues of the one-dimensional Mann-Whitney-Wilcoxon test in two dimensions. Two of the test statistics are new; we call them the Kendall and Spearman statistics. We will then show the asymptotic distributions and carry out empirical comparisons of the Kendall, Spearman and the third two-dimensional Mann-Whitney-Wilcoxon statistics.
35

Ungdomar, kändisar och moral : Cannabisbrukaren i svensk dagpress 2012

Ekman, Jonas, Eriksson, Tomas January 2013 (has links)
Uppsatsen undersöker diskurser om cannabis och hur bilden av ungdomar och vuxna som använder drogen presenteras i tidningarna Aftonbladet, Dagens Nyheter, Expressen och Svenska Dagbladet under år 2012. Studien är en kvalitativ diskursanalys efter Norman Faircoughs tredimensionella metod. Intresset uppkom i och med den diskussion som internationellt växt fram under året. Länder som kulturellt och politiskt stått förebild för svensk utveckling i många frågor rapporterades revidera och omformulera den egna problembilden av cannabis. För en grundläggande förståelse av hur rapporteringen om narkotika sett ut i svensk dagspress har Daniel Törnqvists avhandling “När man talar om knark” legat till grund för arbetets utformning. De medieteoriska utgångspunkterna har varit moralpanik och skiftet från socialpolitik till kriminalpolitik som skett i pressen. Under det analyserade året återkom teman för hur rapporteringen ser ut, beträffande ungdom och narkotika centraliserar samhällets rädsla för den första att komma i kontakt med den senare. Medias förhållningssätt i frågan har tydliga likheter med hur pressen internationellt förhöll sig till subkulturer decennier tillbaka. Den cannabisanvändande kvinnan belyses likaså, tillskrivs en tydlig offerroll och är ur ansvarssynpunkt överskuggad av relationer med män. Mannen är ansvarig för kvinnans missbruk och i förlängningen hennes förfall, en bild som av media presenterats under flera årtionden. Ur vårt material har vi tyckt oss främst finna två diskursiva drag, låt gå och hårdare tag, varandras motsatser.
36

Tests of Bivariate Stochastic Order

Liu, Yunfeng 28 September 2011 (has links)
The purpose of this thesis is to compare rank-based tests of bivariate stochastic order. Given two bivariate distributions $F$ and $G$, the general problem we are dealing with is to test $H_0: F=G$ against $H_1:F<G$, where $F$ and $G$ are independent continuous distributions on $\Re ^2$. (``$F<G$" means that $F(x)\leq G(x)~\forall x\in \Re^2$, and $\exists x\in \Re^2$ such that $F(x)< G(x)$.). In particular, we will analyze three analogues of the one-dimensional Mann-Whitney-Wilcoxon test in two dimensions. Two of the test statistics are new; we call them the Kendall and Spearman statistics. We will then show the asymptotic distributions and carry out empirical comparisons of the Kendall, Spearman and the third two-dimensional Mann-Whitney-Wilcoxon statistics.
37

Electrical resistivity imaging for characterizing dynamic hydrologic systems

Amidu, Sikiru Adetona. Dunbar, John A., January 2008 (has links)
Thesis (Ph.D.)--Baylor University, 2008. / Includes bibliographical references (p.109-118)
38

Involuções fixando muitas componentes e melhorias para o 5/2-Teorema de J. Boardman

Desideri, Patrícia Elaine 05 March 2012 (has links)
Made available in DSpace on 2016-06-02T20:27:39Z (GMT). No. of bitstreams: 1 4150.pdf: 1194001 bytes, checksum: afed3d1198e69a86efd9f7b69562b509 (MD5) Previous issue date: 2012-03-05 / Universidade Federal de Minas Gerais / Let (Mm; T) be a smooth involution on a closed smooth m-dimensional manifold and F = n [j=0 Fj (n < m) its fixed point set, where Fj denotes the union of those components of F having dimension j. The famous Five Halves Theorem of J. Boardman, announced in 1967, establishes that, if F is nonbounding, then m _ 5 2n; further, this estimative is best possible. In this work, we obtain improvements of this theorem, by imposing certain conditions on F. The main result of the work is in Chapter 4, where the improvements in question are obtained by taking into account the decomposability degree of the components of F. Specifically, let ! = (i1; i2; :::; it) be a non-dyadic partition of j, 2 _ j _ n, and s!(x1; x2; :::; xj) the smallest symmetric polynomial over Z2 on degree one variables x1; x2; :::; xj containing the monomial xi1 1 xi2 2 :::xit t . Write s!(Fj) 2 Hj(Fj ;Z2) for the usual cohomology class corresponding to s!(x1; x2; :::; xj). The decomposability degree of Fj , denoted by l(Fj), is the minimum length of a non-dyadic partition ! with s!(Fj) 6= 0 (here, the length of ! = (i1; i2; :::; it) is t). Suppose the fixed point set of (Mm; T) has the form F = ( j [k=0 Fk) [ Fn, where 2 _ j < n < m and Fj is nonbounding. Write n &#56256;&#56320; j = 2pq, where q _ 1 is odd and p _ 0, and set m(n &#56256;&#56320; j) = 2n + p &#56256;&#56320; q + 1 if p _ q and m(n&#56256;&#56320;j) = 2n+2p&#56256;&#56320;q if p _ q. Then we prove that m _ m(n&#56256;&#56320;j)+2j +l(Fj). In addition, given a non-dyadic partition ! = (i1; i2; : : : ; it) of j, 2 _ j < n, we develop a method to construct involutions (Mm; T) with F of the form F = ([k<j Fk)[Fj[Fn, where m = m(n &#56256;&#56320; j) + 2j + t and s![Fj ] 6= 0, for special values of n; j and !. In some special cases, this method shows that the above bound is best possible. For example, this gives the following improvement of the Five Halves Theorem: if the fixed point set F = n [j=0 Fj of (Mm; T) has Fn&#56256;&#56320;1 and Fn nonbounding, then m _ minf2n + l(Fn&#56256;&#56320;1); 2n + l(Fn)g; further, the bounds m _ 2n + l(Fn&#56256;&#56320;1) and m _ 2n + l(Fn) are separately best possible. Other consequence: if the fixed point set F = n [j=0 Fj of (Mm; T) has n = 2k, k _ 3 and vii Fn&#56256;&#56320;1 nonbounding, then m _ 5k &#56256;&#56320; 2, and this bound is best possible (the Five Halves Theorem says that m _ 5k). We also deal with the low codimension phenomenon, which is expressed by the fact that for certain F the codimension m &#56256;&#56320; n is too small; here, the advances obtained are concerned with the fact that, in the considered cases, the number of components of F is not limited as a function of n (in the literature one finds results of this nature with F having two, three or four components). For example, among the results obtained one has: if F has the form F = F3 [ ( n [j=0 j even Fj), with n _ 4 even, and all involved normal bundles are nonbounding, then m _ n + 4; further, this estimative is best possible. Finally, we also study bounds for the case F = Fn [ F4, considering that in the literature one has results involving F = Fn [ Fi for i = 0; 1; 2; 3. For example, we show that if the fixed set of (Mm; T) has the form F = Fn [ F4, n is odd and the normal bundle over F4 is not a boundary, then m _ n + 5; further, this bound is best possible. / Sejam (Mm; T) uma involução suave em uma variedade m-dimensional, fechada e suave Mm e F = n [j=0 Fj (n < m) o seu conjunto de pontos fixos, onde Fj denota a união das componentes de F com dimensão j. O famoso 5=2-Teorema de J. Boardman, anunciado em 1967, estabelece que, se F é não bordante, então m _ 5 2n; além disso, esta estimativa é a melhor possível. Neste trabalho, nós obtemos melhorias para este teorema, impondo certas condições sobre F. O resultado principal se encontra no Capítulo 4, onde as melhorias em questão são obtidas levando-se em conta o grau de decomponibilidade das componentes de F. Especificamente, seja ! = (i1; i2; :::; it) uma partição não diádica de j, 2 _ j _ n, e seja s!(x1; x2; :::; xj) a menor polinomial simétrica sobre Z2, nas variáveis de grau um x1; x2; :::; xj , contendo o monômio xi1 1 xi2 2 :::xit t . Escreva s!(Fj) 2 Hj(Fj ;Z2) para a classe usual de cohomologia correspondente a s!(x1; x2; :::; xj). O grau de decomponibilidade de Fj , denotado por l(Fj), é o menor comprimento de uma partição não diádica ! com s!(Fj) 6= 0 (aqui, o comprimento de ! = (i1; i2; :::; it) é t). Suponhamos que o conjunto de pontos fixos de (Mm; T) tem a forma F = ( j [k=0 Fk) [ Fn, onde 2 _ j < n < m e Fj é não bordante. Escreva n &#56256;&#56320; j = 2pq, onde q _ 1 é ímpar e p _ 0, e tome m(n&#56256;&#56320;j) = 2n+p&#56256;&#56320;q+1, se p _ q, e m(n&#56256;&#56320;j) = 2n+2p&#56256;&#56320;q, se p _ q. Então, provamos que m _ m(n&#56256;&#56320;j)+2j +l(Fj). Em adição, dada uma partição não diádica ! = (i1; i2; : : : ; it) de j, 2 _ j < n, desenvolvemos um método para construir involuções (Mm; T) com F da forma F = ([k<j Fk) [ Fj [ Fn, onde m = m(n &#56256;&#56320; j) + 2j + t e s![Fj ] 6= 0, para valores especiais de n, j e !. Em alguns casos específicos, este método mostra que o limitante acima é o melhor possível. Por exemplo, tal método fornece a seguinte melhoria para o 5=2-Teorema de J. Boardman: se o conjunto de pontos fixos F = n [j=0 Fj de (Mm; T) possui Fn&#56256;&#56320;1 e Fn não bordantes, então m _ minf2n+l(Fn&#56256;&#56320;1); 2n+l(Fn)g; além disso, os limitantes m _ 2n + l(Fn&#56256;&#56320;1) e m _ 2n + l(Fn) são separadamente os melhores possíveis. Outra consequência: se o conjunto de pontos fixos F = n [j=0 Fj de (Mm; T) tem n = 2k, k _ 3 e Fn&#56256;&#56320;1 não bordante, então m _ 5k &#56256;&#56320; 2, e este limitante é o melhor possível (o 5=2-Teorema diz que m _ 5k, nesse caso). Nós também trabalhamos com alguns casos envolvendo fenômenos de baixa codimensão, caracterizados pelo fato que, para específicos conjuntos de pontos fixos F, a codimensão m &#56256;&#56320; n é muito pequena; aqui, os avanços obtidos nos casos considerados relacionam-se à circunstância do número de componentes de F não ser limitado como uma função de n (na literatura, encontramos resultados dessa natureza onde F possui 2, 3 ou 4 componentes). Como exemplo dos resultados obtidos, temos o seguinte: se F tem a forma F = F3 [( n [j=0 j par Fj), com n _ 4 par, e tal que todos os fibrados normais envolvidos são não bordantes, então m _ n + 4; além disso, esta estimativa é a melhor possível. Finalmente, trabalhamos com limitantes para o caso F = Fn [F4, considerandose que na literatura atual temos alguns resultados envolvendo F = Fn [ Fi, para i = 0; 1; 2; 3. Por exemplo, nós mostramos que se o conjunto de pontos fixos de (Mm; T) tem a forma F = Fn [ F4, com n ímpar, e o fibrado normal sobre F4 é não bordante, então m _ n + 5; além disso, esse limitante é o melhor possível.
39

Fibrados, classes de Stiefel-Whitney e resultados de não imersão

Inforzato, Caio Carlevaro 24 September 2012 (has links)
Made available in DSpace on 2016-06-02T20:28:27Z (GMT). No. of bitstreams: 1 4588.pdf: 701327 bytes, checksum: 07aaf91b8be59a3db7c6c5cf38e55c59 (MD5) Previous issue date: 2012-09-24 / Financiadora de Estudos e Projetos / We present an introductory study of smooth manifolds, bundles and Stiefel- Whitney classes (of real vector bundles). We explained that, given a certain smooth m-dimensional manifold, the Stiefel- Whitney classes of its tangent bundle can be used to ensure that such a manifold does not immerse (smoothly) in certain Euclidean spaces Rj . In this sense, we consider the Grassmann manifold G2;n of the 2-subspaces of Rn+2, and we carry out a detailed study of the following non-immersion theorem, proved by V. Oproiu [Proceedings of the Edinburgh Mathematical Society, 1977]: "Let n > 1 be a natural number and consider s = 2r such that s _ 2n < 2s. If n = s - 1, then G2;n does not immerse in R2s-3; if n = s - 1, then G2;n does not immerse in R3s-3." / Apresentamos um estudo introdutório de Variedades Suaves, Fibrados e Classes de Stiefel-Whitney (de _brados vetorias reais). Explicamos que, dada uma certa variedade suave m-dimensional, as classes de Stiefel-Whitney do seu _brado tangente podem ser usadas para garantir que tal variedade não imerge (suavemente) em certos espaços Euclidianos Rj . Nesse sentido, consideramos a variedade Grassmanniana G2;n, variedade dos 2-subespaços de Rn+2, e realizamos um estudo detalhado do seguinte teorema de não imersão, provado por V. Oproiu [Proceedings of the Edinburgh Mathematical Society, 1977]: "Seja n > 1 um natural e considere s = 2r tal que s _ 2n < 2s. Se n 6= s &#1048576; 1, então G2;n não imerge em R2s-3; se n = s - 1, então G2;n não imerge em R3s-3."
40

Fibrados, classes de Stiefel-Whitney e resultados de não imersão / Fibrados, classes de Stiefel-Whitney e resultados de não imersão

Inforzato, Caio Carlevaro 24 September 2012 (has links)
Made available in DSpace on 2016-06-02T20:28:27Z (GMT). No. of bitstreams: 1 4588.pdf: 701327 bytes, checksum: 07aaf91b8be59a3db7c6c5cf38e55c59 (MD5) Previous issue date: 2012-09-24 / Financiadora de Estudos e Projetos / We present an introductory study of smooth manifolds, bundles and Stiefel- Whitney classes (of real vector bundles). We explained that, given a certain smooth m-dimensional manifold, the Stiefel- Whitney classes of its tangent bundle can be used to ensure that such a manifold does not immerse (smoothly) in certain Euclidean spaces Rj . In this sense, we consider the Grassmann manifold G2;n of the 2-subspaces of Rn+2, and we carry out a detailed study of the following non-immersion theorem, proved by V. Oproiu [Proceedings of the Edinburgh Mathematical Society, 1977]: "Let n > 1 be a natural number and consider s = 2r such that s < ou = 2n < 2s. If n different s - 1, then G2;n does not immerse in R2s-3; if n = s - 1, then G2;n does not immerse in R3s-3." / Apresentamos um estudo introdutório de Variedades Suaves, Fibrados e Classes de Stiefel-Whitney (de fibrados vetorias reais). Explicamos que, dada uma certa variedade suave m-dimensional, as classes de Stiefel-Whitney do seu fibrado tangente podem ser usadas para garantir que tal variedade não imerge (suavemente) em certos espaços Euclidianos Rj . Nesse sentido, consideramos a variedade Grassmanniana G2;n, variedade dos 2-subespaços de Rn+2, e realizamos um estudo detalhado do seguinte teorema de não imersão, provado por V. Oproiu [Proceedings of the Edinburgh Mathematical Society, 1977]: "Seja n > 1 um natural e considere s = 2r tal que s < ou = 2n < 2s. Se n for diferente de s - 1, então G2;n não imerge em R2s-3; se n = s - 1, então G2;n não imerge em R3s-3."

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