Provamos que \'C POT. 1\' genericamente difeomorfismos simpléticos ou são Anosov ou possuem entropia topológica limitada por baixo pelo supremo sobre o menor expoente de Lyapunov positivo dos pontos periódicos hiperbólicos. Usando isto exibimos exemplos de difeomorfismos conservativos sobre superfícies que não são pontos de semicontinuidade superior para a entropia topológica. Provamos também que \'C POT. 1\' genericamente difeomorfismos simpléticos não Anosov não admitem extensões simbólicas. Mudando de assunto, Hayashi estendeu um resultado de Mañé, provando que todo difeomorfismo f que possui uma \'C POT. 1\' vizinhança U, onde todos os pontos periódicos de qualquer g \'PERTENCE A\' U são hiperbólicos, é de fato um difeomorfismo Axioma A. Aqui, provamos o resultado análogo a este no caso conservativo, e a partir deste é possível exibir uma demonstração de um fato \"folclore\", a conjectura de Palis no caso conservativo / We prove that a \'C POT.1\' generic symplectic diffeomorphism is either Anosov or the topological entropy is bounded from below by the supremum over the smallest positive Lyapunov exponent of the periodic points. By means of that we give examples of area preserving diffeomorphisms which are not point of upper semicontinuity of entropy function in \'C POT. 1\' topology. We also prove that \'C POT. 1\'- generic symplectic diffeomorphisms outside the Anosov ones do not admit symbolic extension. Changing of subject, Hayashi has extended a result of Mañé, proving that every diffeomorphism f which has a \'C POT. 1\'-neighborhood U, where all periodic points of any g \'IT BELONGS\' U are hyperbolic, it is an Axiom A diffeomorphism. Here, we prove the analogous result in the volume preserving scenario, and using it we prove a \"folklore\" fact, the Palis conjecture in this context

Cette thèse présente un modèle de base de données relationnel étendu : SHIVA, conçu pour permettre la mise en ouvre de bases de connaissances centrées objets. Le modèle SHIVA a été développé dans le cadre du projet SHIRKA : des bases de connaissances centrées objets et, un interpréteur de ce modèle sera utilisé pour écrire le système de gestion de bases de connaissances du système SHIRKA.<br /><br />Le premier chapitre est une description du système SHIRKA et de la représentation des connaissances centrée objets. Dans le deuxième chapitre, les principales extensions du mode relationnel sont exposées. Enfin, le troisième chapitre est consacré au modèle SHIVA.

Le théorème fondamental de l'Arithmétique factorise tout nombre entier en produit de nombres premiers. Le théorème de Jordan-Hölder dévisse de nombreux groupes par leurs suites normales qui se raffinent en suites de composition. Le thème central de cette étude est celui de la dissociation des extensions de corps. Nous dissocions les extensions algébriques par leurs corps intermédiaires de façon à constituer une tour qui comporte le plus grand nombre possible de marches galoisiennes. Nous appelons "galtourables" les extensions admettant une tour de corps dont toutes les marches sont galoisiennes (dite "tour galoisienne"). Deux tours galoisiennes d'une même extension galtourable (finie ou infinie) admettent des raffinements équivalents. Mais il existe des extensions algébriques non galtourables. A toute extension finie est attaché un corps intermédiaire unique, son "corps d'intourabilité", au-delà duquel l'extension n'est plus galtourable. L'ultime marche d'une "tour d'élévation" d'une extension non galourable est alors dite "galsimple" et elle est non galoisienne. Le théorème final de cette thèse dissocie toute extension finie par ses tours d'élévation qui se raffinent en "tours de composition". Nous obtenons ainsi un analogue pour les extensions de corps du théorème de Jordan-Hölder pour les groupes.

L'objet de cette thèse est l'étude mathématique de familles d'espaces-temps satisfaisant aux équations d'Einstein de la Relativité Générale. Deux approches sont considérées pour cette étude. La première partie, composée des trois premiers chapitres, examine les propriétés géométriques des espaces-temps d'Emparan-Reall et de Pomeransky-Senkov, de dimension 5. Nous montrons qu'ils contiennent un trou noir, dont l'horizon des événements est à sections compactes non-homéomorphes à la sphère. Nous en construisons une extension analytique, et prouvons que cette extension est maximale, et unique dans une certaine classe d'extensions pour les espaces-temps d'Emparan-Reall. Nous établissons ensuite le diagramme de Carter-Penrose de ces extensions, puis analysons la structure de l'ergosurface des espaces-temps de Pomeransky- Senkov. La deuxième partie est consacrée à l'étude de données initiales, solutions des équations des contraintes, induites par les équations d'Einstein. Nous effectuons un recollement d'une classe de données initiales avec des données initiales d'espaces-temps de Kerr-Kottler-de Sitter, en utilisant la méthode de Corvino. Nous construisons, d'autre part, des métriques asymptotiquement hyperboliques en dimension 3, satisfaisant les hypothèses du théorème de masse positive à l'exception de la complétude, et ayant un vecteur moment-énergie de genre causal arbitraire.

<p>This thesis presents a quantitative evaluation of an operating system virtualization technology known as Solaris Containers or Solaris Zones, with a special emphasis on measuring the influence of a security technology known as Solaris Trusted Extensions. Solaris Zones is an operating system-level (OS-level) virtualization technology embedded in the Solaris OS that primarily provides containment of processes within the abstraction of a complete operating system environment. Solaris Trusted Extensions presents a specific configuration of the Solaris operating system that is designed to offer multi-level security functionality.</p><p>Firstly, we examine the scalability of the OS with respect to an increasing number of zones. Secondly, we evaluate the performance of zones in three scenarios. In the first scenario we measure - as a baseline - the performance of Solaris Zones on a 2-CPU core machine in the standard configuration that is distributed as part of the Solaris OS. In the second scenario we investigate the influence of the number of CPU cores. In the third scenario we evaluate the performance in the presence of a security configuration known as Solaris Trusted Extensions. To evaluate performance, we calculate a number of metrics using the AIM benchmark. We calculate these benchmarks for the global zone, a non-global zone, and increasing numbers of concurrently running non-global zones. We aggregate the results of the latter to compare aggregate system performance against single zone performance.</p><p>The results of this study demonstrate the scalability and performance impact of Solaris Zones in the Solaris OS. On our chosen hardware platform, Solaris Zones scales to about 110 zones within a short creation time (i.e., less than 13 minutes per zone for installation, configuration, and boot.) As the number of zones increases, the measured overhead of virtualization shows less than 2% of performance decrease for most measured benchmarks, with one exception: the benchmarks for memory and process management show that performance decreases of 5-12% (depending on the sub-benchmark) are typical. When evaluating the Trusted Extensions-based security configuration, additional small performance penalties were measured in the areas of Disk/Filesystem I/O and Inter Process Communication. Most benchmarks show that aggregate system performance is higher when distributing system load across multiple zones compared to running the same load in a single zone.</p>

Sampling theory is an active field of research that spans a variety of disciplines from communication engineering to pure mathematics. Sampling theory provides the crucial connection between continuous and discrete representations of information that enables one store continuous signals as discrete, digital data with minimal error. It is this connection that allows communication engineers to realize many of our modern digital technologies including cell phones and compact disc players. This thesis focuses on certain non-Fourier generalizations of sampling theory and their applications. In particular, non-Fourier analogues of bandlimited functions and extensions of sampling theory to functions on curved manifolds are studied. New results in bandlimited function theory, sampling theory on curved manifolds, and the theory of self-adjoint extensions of symmetric operators are presented. Besides being of mathematical interest in itself, the research contained in this thesis has applications to quantum physics on curved space and could potentially lead to more efficient information storage methods in communication engineering.

Sampling theory is an active field of research that spans a variety of disciplines from communication engineering to pure mathematics. Sampling theory provides the crucial connection between continuous and discrete representations of information that enables one store continuous signals as discrete, digital data with minimal error. It is this connection that allows communication engineers to realize many of our modern digital technologies including cell phones and compact disc players. This thesis focuses on certain non-Fourier generalizations of sampling theory and their applications. In particular, non-Fourier analogues of bandlimited functions and extensions of sampling theory to functions on curved manifolds are studied. New results in bandlimited function theory, sampling theory on curved manifolds, and the theory of self-adjoint extensions of symmetric operators are presented. Besides being of mathematical interest in itself, the research contained in this thesis has applications to quantum physics on curved space and could potentially lead to more efficient information storage methods in communication engineering.

Many firms attempt to ensure the success of new product introductions by applying an existing, well-known brand name to the product. The strategy, known as brand extension, has become commomplace. In recent years, the strategy has been used in media industry. Especially, since the Internet started gaining in popularity in the mid-1990s, the newspaper industry has started applying brand extensions to online markets. For example, United Daily News, Chinatimes, and so on has developed websites of various types. However, we doubt whether it¡¦ll affect consumers¡¦ attitude toward the parent brand. For this reason, we attempt to figure out consumers¡¦attitude toward the newspaper brand when a newspaper office has introduced extensions with good or poor fit. Besides, in this study, we also propose that three factors including ownership status, product attributes, and dominance of the parent brand will influence consumers¡¦s evaluation of the parent brand. Previous research have provided mixed evidence about the reciprocal effects of a brand extension on its parent brand and rarely studied the impact of these four factors on parent brand evaluation, especially in media industy. As a result, we select United Daily News and Appledaily as two objects of the study and find out the extensions (websites) with good and poor fit of these two newspaper brands through group discussing. After T-test analysis, we have some findings as follows: 1.There¡¦s no significant effect of fit on parent brand attitude toward United Daily News, but there¡¦s significant difference for Appledaily. 2.The consumers who think of the newspaper brand as more dominant have higher evaluation of attitude toward the parent brand than those who think of the newspaper brand as less dominant, whether extensions with good or poor fit introduced. 3.The owners of newspaper brands have higher evaluation of attitude toward the parent brand than nonowners, whether extensions with good or poor fit introduced. 4.The product attributes of newspapers brands will affect consumers¡¦s attitude toward the newspaper brands.

Cette thèse porte sur la classification des objets galoisiens d'une algèbre de Hopf. Le concept d'extension de Hopf-Galois, qui a été beaucoup étudié ces dernières années, est une généralisation du concept d'extension galoisienne de corps, mais aussi un analogue des fibrés principaux dans le cadre de la géométrie non commutative. Si $H$ est une algèbre de Hopf, une algèbre $H$-comodule $(Z,\delta: Z \to Z \otimes H)$ est une $H$-extension de Hopf-Galois d'une sous-algèbre $B\subset Z$ si l'ensemble des éléments co\"\i nvariants de $Z$ co\"\i ncide avec $B$ et si l'application canonique $\beta : Z \otimes _B Z \to Z\otimes H$ définie par <br />$$ \beta (x\otimes y ) = \delta (x) (y\otimes 1)$$ est une bijection. Les objets galoisiens forment une classe importante d'extensions de Hopf-Galois ; ce sont celles dont la sous-algèbre des co\"\i nvariants se réduit à l'anneau de base. Bien qu'une littérature abondante ait été consacrée aux extensions de Hopf-Galois, on a peu de résultats sur leur classification à isomorphisme près. Pour contourner la difficulté de classer les extensions de Hopf-Galois à isomorphisme près, Kassel a introduit et développé avec Schneider une relation d'équivalence sur les extensions de Hopf-Galois qu'il a appelée homotopie. <br /><br />Dans cette thèse nous donnons des résultats de classification à homotopie et à isomorphisme près. Notre approche de la classification des objets galoisiens tourne autour de trois axes. <br />\begin{itemize} <br />\item[a)] La construction explicite de représentants des classes d'homotopie des objets galoisiens de l'algèbre $U_q(\mathfrak{g})$ associée par Drinfeld et Jimbo à une algèbre de Lie $\mathfrak{g}$, explicitant ainsi un théorème de Kassel et Schneider. <br />\item[b)] Une étude des objets galoisiens de l'alg\` ebre quantique $O_q (SL(2))$ des fonctions sur le groupe $SL (2)$, et donc un résultat de classification en dimension infinie; nous donnons la classification à isomorphisme près et des résultats partiels pour la classification à homotopie près. <br />\item[c)] Une étude systématique de la classification à isomorphisme et à homotopie près pour les algèbres de Hopf de dimension $\leq 15$ ; nous synthétisons des résultats éparpillés dans la littérature, portant sur des familles d'algèbres de Hopf pointées ou semisimples et nous complétons ces résultats en donnant la classification des objets galoisiens d'une algèbre de Hopf de dimension $8$ qui n'est ni semisimple ni <br />pointée. <br />\end{itemize}

Um anel noetheriano S satisfaz a propriedade ( ) se todas as extens~oes essenciais c clicas de S-m odulos simples s~ao artinianas. An eis noetherianos com esta propriedade veri cam a Conjectura de Jacobson, que e um famoso problema em aberto em teoria de an eis. Neste trabalho investigamos esta propriedade em an eis de operadores diferenciais R[ ; ], onde R e um anel comutativo noetheriano e uma deriva c~ao de R. Mais especi camente, estudamos condi c~oes necess arias e su cientes para que R[ ; ] satisfa ca ( ), quando R e um anel -simples e, tamb em, no caso em que este e um anel -primitivo. Al em disso, caracterizamos os an eis de operadores diferenciais C[x; y][ ; ] que satisfazem ( ). / A Noetherian ring S satis es the property ( ) if any cyclic essential extension of simple S-modules are Artinian. Noetherian rings with this property verify Jacobson's Conjecture, which is a famous open problem in ring theory. In this work we investigate this property in di erential operators rings R[ ; ], where R is a commutative Noetherian ring and is a derivation of R. More precisely, we study necessary and su cient conditions for R[ ; ] to satisfy property ( ) whenever R is a -simple ring and also for the case where it is a -primitive ring. Furthermore, we characterize the di erential operator rings C[x; y][ ; ] satisfying ( ).