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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.
1

Divisão de distribuições temperadas por polinômios. / Division of tempered distributions by polynomials.

Garcia, Mariana Smit Vega 29 August 2008 (has links)
Este trabalho apresenta uma demonstração completa do Teorema de L. Hörmander sobre a divisão de distribuições (temperadas) por polinômios. O caso n=1 é apresentado detalhadamente e serve como motivação para as técnicas utilizadas no caso geral. Todos os pré-requisitos para a demonstração de Hörmander (os Teoremas de Seidenberg-Tarski, de Puiseux e da Extensão de Whitney) são discutidos com detalhes. Como conseqüência do Teorema, segue que todo operador diferencial parcial linear com coeficientes constantes não nulo admite solução fundamental temperada. / This dissertation presents a thorough proof of L. Hörmander\'s theorem on the division of (tempered) distributions by polynomials. The case n=1 is discussed in detail and serves as a motivation for the techniques that are utilised in the general case. All the prerequisites for Hörmander\'s proof (the Theorems of Seidenberg-Tarski, of Puiseux and Whitney\'s Extension Theorem) are discussed in detail. As a consequence of this theorem, it follows that every non zero partial diffe\\-rencial operator with constant coefficients has a tempered fundamental solution.
2

Divisão de distribuições temperadas por polinômios. / Division of tempered distributions by polynomials.

Mariana Smit Vega Garcia 29 August 2008 (has links)
Este trabalho apresenta uma demonstração completa do Teorema de L. Hörmander sobre a divisão de distribuições (temperadas) por polinômios. O caso n=1 é apresentado detalhadamente e serve como motivação para as técnicas utilizadas no caso geral. Todos os pré-requisitos para a demonstração de Hörmander (os Teoremas de Seidenberg-Tarski, de Puiseux e da Extensão de Whitney) são discutidos com detalhes. Como conseqüência do Teorema, segue que todo operador diferencial parcial linear com coeficientes constantes não nulo admite solução fundamental temperada. / This dissertation presents a thorough proof of L. Hörmander\'s theorem on the division of (tempered) distributions by polynomials. The case n=1 is discussed in detail and serves as a motivation for the techniques that are utilised in the general case. All the prerequisites for Hörmander\'s proof (the Theorems of Seidenberg-Tarski, of Puiseux and Whitney\'s Extension Theorem) are discussed in detail. As a consequence of this theorem, it follows that every non zero partial diffe\\-rencial operator with constant coefficients has a tempered fundamental solution.
3

Translation invariant Banach spaces of distributions and boundary values of integral transform / Translaciono invarijantni Banahovi prostori distribucija i granične vrednosti preko integralne transformacije

Dimovski Pavel 21 April 2015 (has links)
<p>We use common notation &lowast; for distribution (Scshwartz), (M<sub>p</sub>) (Beurling) i {M<sub>p</sub>} (Roumieu) setting. We introduce and study new (ultra) distribution spaces, the test function spaces&nbsp;<em>D<sup>&lowast;</sup><sub>E</sub></em>&nbsp; and their strong duals <em>D<sup><span style="font-size: 10px;">&#39;</span>&lowast;</sup><sub>E&rsquo;*</sub></em>.These spaces generalize the spaces <em>D<sup>&lowast;</sup><sub>L<sup>q</sup></sub> , D&#39;<sup>&lowast;</sup><sub>L<sup>p</sup></sub> , B&rsquo;*</em>&nbsp;and their weighted versions. The construction of our new (ultra)distribution &nbsp;spaces is based on the analysis of a suitable translation-invariant Banach space of (ultra)distribution <em>E</em>&nbsp;with continuous translation group, which turns out to be a convolution module over the Beurling algebra&nbsp;<em>L<sup>1</sup><sub>&omega;</sub></em>, where the weight &nbsp;&omega; is related to the translation operators on <em>E</em>.&nbsp;The&nbsp;Banach space&nbsp;<em>E</em><sup>&rsquo;</sup><sub>&lowast;</sub>&nbsp;stands for&nbsp;<em>L<sup>1</sup><sub>&omega;ˇ</sub> &lowast; E</em>&rsquo;.&nbsp;We apply our results to the study of the&nbsp;convolution of ultradistributions. The spaces of convolutors&nbsp;<em>O<span style="font-size: 12px;">&rsquo;<sup>&lowast;</sup></span><span style="font-size: 8.33333px;">C</span></em><span style="font-size: 12px;"><em>&nbsp;(</em><strong>R</strong><em><sup>n</sup>)</em>&nbsp;</span>for tempered&nbsp;ultradistributions are analyzed via the duality with respect to the test function<br />spaces<span style="font-size: 12px;">&nbsp;<em>O<sup>&lowast;</sup><sub>C</sub> (</em><strong>R</strong><em><sup>n</sup>)</em>,&nbsp;</span>introduced in this thesis. Using the properties of translationinvariant<br />Banach space of ultradistributions <em>E</em> we obtain a full characterization of<br />the general convolution of Roumieu ultradistributions via the space of integrable<br />ultradistributions is obtained. We show: The convolution of two Roumieu ultradistributions&nbsp;<span style="font-size: 12px;"><em>T, S &isin; D&rsquo;<sup>{Mp}</sup> (</em><strong>R</strong><em><sup>n</sup>)&nbsp;</em> exists if and only if&nbsp;<em>(</em></span><em>&phi;</em><span style="font-size: 12px;"><em>&nbsp;&lowast; &Scaron;) T &isin; D<sup>&rsquo;{Mp}</sup><sub>L<sup>1</sup></sub>(</em><strong>R</strong><em><sup>n</sup>)</em>&nbsp; for every </span><em>&phi;</em><span style="font-size: 12px;"><em>&nbsp;&isin; D <sup>{Mp}</sup> (</em><strong>R</strong><em><sup>n</sup>)</em>.&nbsp;</span>We study boundary values of holomorphic functions defined in tube domains. New edge of the wedge theorems are obtained. The results<br />are then applied to represent<span style="font-size: 12px;">&nbsp;<em>D&rsquo;<sub>E&rsquo;*</sub></em></span><span style="font-size: 12px;">&nbsp;&nbsp;</span>as a quotient space of holomorphic functions.<br />We also give representations of elements of<span style="font-size: 12px;">&nbsp;<em>D&rsquo;<sub>E&rsquo;*</sub></em></span><span style="font-size: 12px;">&nbsp;&nbsp;</span>via the heat kernel method.</p> / <p>Koristimo oznaku &lowast; za distribuciono (Svarcovo), (Mp) (Berlingovo) i&nbsp;{Mp} (Roumieuovo) okruženje. Uvodimo i prouavamo nove (ultra)distribucione&nbsp;prostore, &nbsp;test funkcijske prostore <em>D</em><sup>&lowast;</sup><sub>E</sub> i njihove duale <em>D<sup>&#39;</sup></em><sup>&lowast;</sup><sub><em>E&#39;*</em></sub>.&nbsp;&nbsp;Ovi prostori uop&scaron;tavaju&nbsp;<br />prostore <em>D</em><sup>&lowast;</sup><sub>Lq</sub> , <em>D</em><sup>&#39;&lowast;</sup><sub>Lp</sub> , <em>B<sup>&#39;</sup></em><sup>&lowast;</sup> i njihove težinske verzije. Konstrukcija na&scaron;ih novih&nbsp;<br />(ultra)distribucionih prostora je zasnovana na analizi odgovarajuićh translaciono&nbsp;<br />- invarijantnih Banahovih prostora (ultra)distribucija koje označavamo sa&nbsp;<em>E</em>. Ovi prostori imaju neprekidnu grupu translacija, koja je konvolucioni modul&nbsp;nad &nbsp;Beurlingovom algebrom L<sup>1</sup><sub>&omega;</sub>, gde je težina &omega; povezana sa operatorima translacije&nbsp;<br />prostora <em>E</em>. Banahov prostor <em>E<sup>&#39;</sup></em><sub>&lowast;&nbsp;</sub>označava prostor <em>L</em><sup>1</sup><sub>&omega;˅</sub> &lowast; <em>E<sup>&#39;</sup></em>. Koristeći dobijene&nbsp;<br />rezultata proučavamo konvoluciju ultradistribucija. Prostori konvolutora &nbsp;<em>O<sup>&#39;</sup></em><sup>&lowast;</sup><sub><em>C&nbsp;</em></sub>(<strong>R</strong><sup>n</sup>)&nbsp;temperiranih ultradistribucija, analizirani su pomoću dualnosti&nbsp;<br />test funkcijskih prostora <em>O</em><sup>&lowast;</sup><sub><em>C</em></sub> (<strong>R</strong><sup>n</sup>), definisanih u ovoj tezi. Koristeći svojstva&nbsp;<br />translaciono - invarijantnih Banahovih prostora temperiranih ultradistribucija,&nbsp;<br />opet označenih sa <em>E</em>, dobijamo karakterizaciju konvolucije Romuieu-ovih &nbsp;ultradistribucija,&nbsp;preko integrabilnih ultradistribucija. Dokazujemo da: konvolucija&nbsp;<br />dve Roumieu-ove ultradistribucija <em>T</em>, <em>S</em> &isin; <em>D<sup>&#39;</sup></em><sup>{Mp}&nbsp;</sup>(<strong>R</strong><sup>n</sup>) postoji ako i samo ako (&phi; &lowast; <em>S</em>ˇ)<em>T</em> &isin; <em>D<sup>&#39;</sup></em><sup>{Mp}&nbsp;</sup><sub>L<sup>1</sup></sub> (<strong>R</strong><sup>n</sup>) za svaki &phi; &isin; <em>D</em><sup>{Mp}</sup>(<strong>R</strong><sup>n</sup>). Takođe, proučavamo granične vrednosti holomorfnih funkcija definisanih na tubama. Dokazane su nove teoreme &rdquo;otrog klina&rdquo;. Rezultati se zatim koriste za prezentaciju <em>D<sup>&#39;</sup><sub>E<sup>&#39;</sup></sub></em><sub>&lowast;&nbsp;</sub>preko faktor prostora holomorfnih funkcija. Takođe, data je prezentacija elemente <em>D</em><sup>&#39;</sup><sub><em>E<sup>&#39;</sup></em>&lowast;&nbsp;</sub>koristeći heat kernel metode.</p>
4

Mathematical modelling of image processing problems : theoretical studies and applications to joint registration and segmentation / Modélisation mathématique de problèmes relatifs au traitement d'images : étude théorique et applications aux méthodes conjointes de recalage et de segmentation

Debroux, Noémie 15 March 2018 (has links)
Dans cette thèse, nous nous proposons d'étudier et de traiter conjointement plusieurs problèmes phares en traitement d'images incluant le recalage d'images qui vise à apparier deux images via une transformation, la segmentation d'images dont le but est de délimiter les contours des objets présents au sein d'une image, et la décomposition d'images intimement liée au débruitage, partitionnant une image en une version plus régulière de celle-ci et sa partie complémentaire oscillante appelée texture, par des approches variationnelles locales et non locales. Les relations étroites existant entre ces différents problèmes motivent l'introduction de modèles conjoints dans lesquels chaque tâche aide les autres, surmontant ainsi certaines difficultés inhérentes au problème isolé. Le premier modèle proposé aborde la problématique de recalage d'images guidé par des résultats intermédiaires de segmentation préservant la topologie, dans un cadre variationnel. Un second modèle de segmentation et de recalage conjoint est introduit, étudié théoriquement et numériquement puis mis à l'épreuve à travers plusieurs simulations numériques. Le dernier modèle présenté tente de répondre à un besoin précis du CEREMA (Centre d'Études et d'Expertise sur les Risques, l'Environnement, la Mobilité et l'Aménagement) à savoir la détection automatique de fissures sur des images d'enrobés bitumineux. De part la complexité des images à traiter, une méthode conjointe de décomposition et de segmentation de structures fines est mise en place, puis justifiée théoriquement et numériquement, et enfin validée sur les images fournies. / In this thesis, we study and jointly address several important image processing problems including registration that aims at aligning images through a deformation, image segmentation whose goal consists in finding the edges delineating the objects inside an image, and image decomposition closely related to image denoising, and attempting to partition an image into a smoother version of it named cartoon and its complementary oscillatory part called texture, with both local and nonlocal variational approaches. The first proposed model addresses the topology-preserving segmentation-guided registration problem in a variational framework. A second joint segmentation and registration model is introduced, theoretically and numerically studied, then tested on various numerical simulations. The last model presented in this work tries to answer a more specific need expressed by the CEREMA (Centre of analysis and expertise on risks, environment, mobility and planning), namely automatic crack recovery detection on bituminous surface images. Due to the image complexity, a joint fine structure decomposition and segmentation model is proposed to deal with this problem. It is then theoretically and numerically justified and validated on the provided images.

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