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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.
181

Supergravity duals to five-dimensional supersymmetric gauge theories

Gregory, Carolina Matté January 2017 (has links)
In this thesis we study gauge/gravity duals in the 5d/6d AdS/CFT correspondence. We start with field theories defined on squashed five-spheres with SU(3) × U(1) symmetry. These five-sphere backgrounds are continuously connected to the round sphere. We find a one-parameter family of 3/4 BPS deformations and a two-parameter family of (generically) 1/4 BPS deformations. The gravity duals are constructed in Euclidean Romans F(4) gauged supergravity in six dimensions, and uplift to massive type IIA supergravity. We holographically renormalize the Romans theory, and use our general result to compute the renormalized on-shell actions for the solutions. The results agree perfectly with the large N limit of the dual gauge theory partition function, which we compute using large N matrix model techniques. In addition we compute BPS Wilson loops in these backgrounds, both in supergravity and in the large N matrix model, again finding precise agreement. We conjecture a general formula for the partition function on any five-sphere background, which for fixed gauge theory depends only on a certain supersymmetric Killing vector. We then proceed to study Euclidean Romans supergravity in six dimensions with a non-trivial Abelian R-symmetry gauge field. We show that supersymmetric solutions are in one-to-one correspondence with solutions to a set of differential constraints on an SU(2) structure. As an application of our results we (i) show that this structure reduces at a conformal boundary to the five-dimensional rigid supersymmetric geometry previously studied, (ii) find a general expression for the holographic dual of the VEV of a BPS Wilson loop, matching an exact field theory computation, (iii) construct holographic duals to squashed Sasaki-Einstein backgrounds, again matching to a field theory computation, and (iv) find new analytic solutions to the squashed five-sphere background. We also analyse the classification of gravity duals with zero B-field.
182

Instabilities in asymptotically AdS spacetimes

Dold, Dominic Nicolas January 2018 (has links)
In recent years, more and more efforts have been expended on the study of $n$-dimensional asymptotically anti-de Sitter spacetimes $(\mathcal{M},g)$ as solutions to the Einstein vacuum equations \begin{align*} \mathrm{Ric}(g)=\frac{2}{n-2}\Lambda\, g \end{align*} with negative cosmological constant $\Lambda$. This has been motivated mainly by the conjectured instability of these solutions. The author of this thesis joins these efforts with two contributions, which are themselves independent of each other. In the first part, we are concerned with a superradiant instability for $n=4$. For any cosmological constant $\Lambda=-3/\ell^2$ and any $\alpha < 9/4$, we find a Kerr-AdS spacetime $(\mathcal{M},g_{\mathrm{KAdS}})$, in which the Klein-Gordon equation \begin{align*} \Box_g\psi+\frac{\alpha}{\ell^2}\psi=0 \end{align*} has an exponentially growing mode solution satisfying a Dirichlet boundary condition at infinity. The spacetime violates the Hawking-Reall bound $r_+^2 > |a|\ell$. We obtain an analogous result for Neumann boundary conditions if $5/4 < \alpha < 9/4$. Moreover, in the Dirichlet case, one can prove that, for any Kerr-AdS spacetime violating the Hawking-Reall bound, there exists an open family of masses $\alpha$ such that the corresponding Klein-Gordon equation permits exponentially growing mode solutions. Our result provides the first rigorous construction of a superradiant instability for a negative cosmological constant. In the second part, we study perturbations of five-dimensional Eguchi-Hanson-AdS spacetimes exhibiting biaxial Bianchi IX symmetry. Within this symmetry class, the Einstein vacuum equations are equivalent to a system of non-linear partial differential equations for the radius $r$ of the spheres, the Hawking mass $m$ and $B$, a quantity measuring the squashing of the spheres, which satisfies a non-linear wave equation. First we prove that the system is well-posed as an initial-boundary value problem around infinity $\mathcal{I}$ with $B$ satisfying a Dirichlet boundary condition. Second, we show that initial data in the biaxial Bianchi IX symmetry class around Eguchi-Hanson-AdS spacetimes cannot form horizons in the dynamical evolution.
183

Identifikace požadavků kladených na sportovní manažery v procesu náboru v České republice a Německu / Identification of sport manager's role and creation of the type position of a sport manager in the Czech Republic and Germany

Vítek, Zbyněk January 2018 (has links)
Title: Identification of sport manager's role and creation of the type position of a sport manager in the Czech Republic and Germany Objectives: The main objective of the primary survey is to examine the job-side situation of "Sports Manager" on the labour market on the Czech Republic and Germany. Compare the differences between demands for sports managers and use the results of empirical research to introduce a sports manager. The partial goals, comments and recommendations were formulated as follows: 1) Determine which knowledge and skills are relevant to HR department (human recources department) and quantify them. 2) Verify that HR department requires education and practice, and specify the type of education, length and type of practice. Methods: The theoretical part is processed in the form of a research. From professional literature and publications. A comparison method was used to fulfill the scientific research objective. We have added the findings by formulating recommendations for the implementation of the recruitment and selection process in order to obtain the most suitable candidate for the position of "sports manager". Results: From the empirical knowledge and research of recruitment insertions are distinct the identification and difference of the requirements for the professional...
184

Da fantasia à realidade, da realidade à fantasia: aspectos culturais, históricos e mercadológicos das campanhas publicitárias de games

Ayala, Michel Angelo Moia 23 April 2012 (has links)
Made available in DSpace on 2016-08-03T12:29:35Z (GMT). No. of bitstreams: 1 Michel Ayala PG 1_29.pdf: 4309536 bytes, checksum: 7493a12007c355443ec9aeb891166ca2 (MD5) Previous issue date: 2012-04-23 / A pesquisa tem como objetivo geral compreender como as empresas fabricantes de consoles de videogames da última geração (Sony, Microsoft e Nintendo) utilizam a publicidade para atingir os consumidores. O corpus de análise e interpretação delimita-se em oito peças publicitárias audiovisuais e o período de análise é de 2010 a 2011. As estratégicas metodológicas utilizadas são: quanto aos dados de pesquisa, o estudo é essencialmente qualitativo; em relação aos objetivos, a pesquisa é exploratória; quanto às fontes para obtenção de dados, a pesquisa é bibliográfica e empírica, sendo a fase empírica dividida em observação não-participante, descrição dos anúncios de games e análise de conteúdo audiovisual. Após as análises, demonstrou-se que, apesar de os games estarem na vida cotidiana e serem sonho de consumo de muitas pessoas, sua divulgação ainda é restrita a um número limitado de jogadores. Observa-se que, nas campanhas analisadas como um conjunto, há uma preocupação maior com o público adulto, o que não ocorria há cinco anos, na geração anterior de consoles. Apesar disso, os consoles ainda não são enxergados com todas as suas potencialidades tecnológicas e culturais.
185

Some aspects of abelian and nonabelian T-duality and the gauge/gravity correspondence / Alguns aspectos da dualidade T abeliana e não-abeliana e a correspondência gauge/gravidade

Araujo, Thiago Rocha [UNESP] 16 February 2016 (has links)
Submitted by THIAGO ROCHA ARAUJO (taraujo@ift.unesp.br) on 2016-02-18T13:06:31Z No. of bitstreams: 1 thesis.pdf: 2041737 bytes, checksum: e20834514f664eb4d2cf9905a1e49015 (MD5) / Approved for entry into archive by Ana Paula Grisoto (grisotoana@reitoria.unesp.br) on 2016-02-19T19:04:25Z (GMT) No. of bitstreams: 1 araujo_tr_dr_ift.pdf: 2041737 bytes, checksum: e20834514f664eb4d2cf9905a1e49015 (MD5) / Made available in DSpace on 2016-02-19T19:04:25Z (GMT). No. of bitstreams: 1 araujo_tr_dr_ift.pdf: 2041737 bytes, checksum: e20834514f664eb4d2cf9905a1e49015 (MD5) Previous issue date: 2016-02-16 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Nessa tese estudamos propriedades de soluções de supergravidade tipo II obtidas através da dualidade T abeliana e não abeliana. Também determinamos, através da conjectura gauge/gravidade, aspectos da teoria de campos dual a essas soluções obtidas por dualidade T. Consideramos três tipos distintos de soluções: duais a teorias de campos que confinam, duais a teoria de campos conformes e duais a teoria de campos não-relativistas. Concluimos essa tese com uma análise dos laços de Wilson em soluções com simetria não relativista. / In this thesis we study properties of type II supergravity solutions generated by abelian and nonabelian T-duality. Also we determine, through the gauge/gravity conjecture, some aspects of the field theory dual to the supergravity solutions obtained by T-dualization. We consider three distinct types of backgrounds solutions, namely, backgrounds that are dual to confining field theories, backgrounds dual to conformal field theories and those dual to nonrelativistic field theories. We conclude this thesis with an analysis of Wilson loops on backgrounds with nonrelativistic symmetries. / CNPq: 140588/2012-4
186

Retrato falado: o perfil dos escravos nos anúncios de jornais da Paraíba (1850-1888)

Dias, Elainne Cristina Jorge 25 March 2013 (has links)
Made available in DSpace on 2015-05-14T12:23:11Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 1463283 bytes, checksum: d2336e28ed67dce0a8c7f09a068ae981 (MD5) Previous issue date: 2013-03-25 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This work intends to analyze the advertisements for slaves contained in Brazilian periodicals that circulated in the last decades of slavery. Through the ads will be possible to understand aspects of the social condition in which lived the captives and its forms of struggle and resistance. Initially, he has been trying to discuss the role of the press in the marketing of the slaves, as well as the economic, social and political changes that occurred in Paraiba during the period in question. This is because a large number of commercial transactions involving slaves was initiated through advertisements or in the newspaper where typography was printed. Then we tried to analyze the condition of captivity in which lived the captives, such as: housing, clothing, food, hygienic conditions and, since these factors were instrumental in the development of diseases and, consequently, the health problems. Finally, it was intended to be understood, in particular, the escape of slaves, ads to draw a profile of the captives who were fleeing and presents them not as victims or rebels, but as historical subjects who thought and acted by means of negotiations, struggles, conflicts and solidarity networks to survive before the complex world that was the captivity. / Este trabalho se propõe a analisar os anúncios referentes a escravos contidos nos periódicos paraibanos que circularam nas últimas décadas da escravidão. Através dos anúncios será possível compreender aspectos da condição social em que viviam os cativos e de suas formas de luta e resistência. Inicialmente, buscou-se discutir o papel da imprensa na comercialização dos escravos, como também as mudanças econômicas, sociais e políticas que ocorreram na Paraíba no período em questão. Isto porque, grande parte das transações comerciais que envolviam escravos era iniciada por meio dos anúncios ou na tipografia onde o jornal era impresso. Em seguida, procurou-se analisar a condição de cativeiro em que viviam os cativos, como: moradia, vestimentas, alimentação, condições higiênicas e de trabalho, já que esses fatores foram determinantes para o desenvolvimento das doenças e, consequentemente, os problemas de saúde. Finalmente, pretendeu-se compreender, particularmente, os anúncios de fuga de escravos, para, assim, traçar um perfil dos cativos que fugiam e apresenta-los não como vítimas ou rebeldes, mas como sujeitos históricos que pensavam e agiam por meio de negociações, lutas, conflitos e redes de solidariedade para sobreviverem diante do complexo mundo que foi o cativeiro.
187

Buraco negros, correspond?ncia AdS/BCFT e fluido/gravidade / Black hole, AdS/BCFT and fluid/gravity correspondences

Silva, Madson Rubem Oliveira 22 May 2015 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-03-22T19:28:11Z No. of bitstreams: 1 MadsonRubemOliveiraSilva_TESE.pdf: 1495464 bytes, checksum: 0d35c3d788f1373d1f29cb97ab81c05a (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-03-23T23:12:57Z (GMT) No. of bitstreams: 1 MadsonRubemOliveiraSilva_TESE.pdf: 1495464 bytes, checksum: 0d35c3d788f1373d1f29cb97ab81c05a (MD5) / Made available in DSpace on 2016-03-23T23:12:57Z (GMT). No. of bitstreams: 1 MadsonRubemOliveiraSilva_TESE.pdf: 1495464 bytes, checksum: 0d35c3d788f1373d1f29cb97ab81c05a (MD5) Previous issue date: 2015-05-22 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / A equa??o de Einstein com constante cosmol?gica negativa gera um espa?o-tempo d + 1?dimens?es, que denominamos de espa?o anti de Sitter, AdSd+1, que nos referimos de "bulk". O principio hologr?fico afirma que a gravidade qu?ntica sobre o AdSd+1 ? codificada por uma teoria de contorno, uma CFTd. Por exemplo, uma teoria de cordas IIB sobre uma espa?o-tempo assintoticamente AdS5 ? S 5 ? dual a uma teoria de gauge de super Yang-Mills N = 4 SYM no espa?o-tempo de 4?dimens?es. Outro exemplo ? a rela- ??o entre a equa??o de Einstein no "bulk"e a equa??o hidrodin?mica descreve uma teoria efetiva no contorno, o qual denominamos de fluido/gravita??o. Uma extens?o da dualidadeAdS/CFT foi proposta por Takayanagi que denominou de correspond?ncia AdS/BCFT. O contorno do CFT extende-se para o "bulk"e restringe o AdSd+1. Quando impomos a condi??o de Neumann sobre a extens?o do contorno obtemos uma equa??o de movimento din?mica que determina a forma da extens?o. Da perspectiva da correspond?ncia fluido/gravita??o o tensor energia-momento do fluido residindo no contorno ser? a fonte da geometria do "bulk". Ampliando a proposta de Takayanagi para correspond?ncia fluido/gravita??o estudaremos a consist?ncia do AdS/BCFT a temperatura finita ou equivalentemente a geometria de BH no "bulk". / Einstein?s equations with negative cosmological constant possess the so-called anti de Sitter space, AdSd+1, as one of its solutions. We will later refer to this space as to the "bulk". The holographic principle states that quantum gravity in the AdSd+1 space can be encoded by a d?dimensional quantum field theory on the boundary of AdSd+1 space, invariant under conformal transformations, a CFTd. In the most famous example, the precise statement is the duality of the type IIB string theory in the space AdS5 ? S 5 and the 4?dimensional N = 4 supersymmetric Yang-Mills theory. Another example is provided by a relation between Einstein?s equations in the bulk and hydrodynamic equations describing the effective theory on the boundary, the so-called fluid/gravity correspondence. An extension of the "AdS/CFT duality"for the CFT?s with boundary was proposed by Takayanagi, which was dubbed the AdS/BCFT correspondence. The boundary of a CFT extends to the bulk and restricts a region of the AdSd+1. Neumann conditions imposed on the extension of the boundary yield a dynamic equation that determines the shape of the extension. From the perspective of fluid/gravity correspondence, the shape of the Neumann boundary, and the geometry of the bulk is sourced by the energy-momentum tensor T?? of a fluid residing on this boundary. Clarifying the relation of the Takayanagi?s proposal to the fluid/gravity correspondence, we will study the consistence of the AdS/BCFT with finite temperature CFT?s, or equivalently black hole geometries in the bulk.
188

Rekommendationssystem för riktad annonsering : En studie av innehållsbaserad rekommendation i system med användare, element och annonser kopplade till en gemensam uppsättning diskreta metadata / Recommender system for targeted advertising

Andersson, Andreas, Ottehall, Henrik January 2017 (has links)
Advertising in mobile apps are increasing and so is the need to show the right ad to the right user. This study was conducted in cooperation with Seekly AB, a company whose app displays a feed with upcoming events in a users immediate area. In this app, every event is associated with an interest and users can choose interests to follow in a list. Seekly wanted to use so called behavioral targeting to show ads in their feed. The solution that was developed is useful for all Seekly-like systems and consists of a content based recommender system that chooses ads based on the interests a user has selected and events and ads that the user has shown an interest in. Apps that in some way or another resembles the Seekly app are not uncommon and recommender systems for behavioral targeting suited for this kind of system are to the best of our knowledge not described in the literature. The resulting recommender system has been implemented and shown to be able to recommend ads that has been associated with interests that match the interests selected by the user and/or amplified by his or her behavior. There are also indications that the system would be able to increase the number of ad clicks compared to randomly selected ads, but no statistically significant proof was found.
189

Kommunikationsgränssnitt mot GP&amp;C transponder / Communication interface to a GP&amp;C transponder

Johansson, Anders January 2002 (has links)
Examensarbetet som beskrivs i denna rapport handlar om en ny teknik för att förbättra säkerheten för flygplan i luften och i närheten av flygplatser. Denna teknik benämns ADS-B (Automatic Dependent Surveillance Broadcast), och är tänkt att göra det möjligt för piloter att själva få information om trafik i närområdet. Nuvarande system baserar sig i huvudsak på visuella observationer från flygledare i kontrolltorn samt radarspaning omkring flygplatserna. Med det nuvarande systemet kommer det att bli både dyrt och svårt att upprätthålla en acceptabel nivå på flygsäkerheten när trafiken ökar. Arbetet har bedrivits i AerotechTelubs regi i Linköping samt med hjälp ifrån företaget Sectra Wireless Technologies AB. Huvuddelen av arbetet inriktar sig på implementerandet av C-funktioner för att hantera kommunikationen och sammankopplandet av ett tidigare skapat system, för grafikvisning, med en transponder som hanterar ADS-B (tillverkad av Sectra). Målet med detta var att göra förberedande arbete åt AerotechTelub som de förhoppningsvis kommer att kunna använda i ett eventuellt kommande projekt. Rapporten tar upp några standarder som hör till konceptet GP&amp;C (Global Positioning &amp; Communication), samt beskriver de delar som ligger till grund för programmets funktion. Examensarbetet har resulterat i ett demonstrationsprogram för att visa hur en lösning av problemet kan se ut. Det har tyvärr inte gått att säkerställa om programmet fungerar till fullo, men genom simuleringar och andra tester har huvuddelen av programmets funktioner gått att verifiera.
190

Contribution à l’étude thermodynamique du système Pb-Bi-(Hg)-Fe-(Al,Cr)-O : étude des systèmes Bi2O3–PbO–Al2O3 et Bi2O3–PbO–Fe2O3 / Contribution to the thermodynamic study of the system Pb-Bi-(Hg)-Fe-(Al,Cr)-O : Study of the Bi2O3–PbO–Al2O3 and Bi2O3–PbO–Fe2O3 systems

Oudich, Fayssal 16 December 2014 (has links)
Le présent travail de recherche s’inscrit dans un projet global, dont le but est de comprendre et résoudre un problème de corrosion d’un acier dit T91 par un mélange métallique liquide de plomb et bismuth. Il présente un intérêt pour la communauté nucléaire qui envisage de développer une nouvelle génération de réacteurs dits ADS. Ce travail est une contribution à l’étude thermodynamique d’un système plus complexe composé de plusieurs éléments : Al, Bi, Pb, Fe, Cr et l’oxygène. Plus précisément, il a été focalisé sur les systèmes à base de mélanges d’oxydes Bi2O3 + PbO + Al2O3 et Bi2O3 + PbO + Fe2O3. Un travail expérimental a été accompli, au cours duquel ces mélanges à différentes proportions ont été recuits à une température supérieure à 600 °C pendant plusieurs jours, suivi de l’analyse des échantillons par des techniques de pointe. Il a permis de découvrir les différents produits formés dans les différentes conditions de température, de compositions et atmosphères. Les résultats ont permis de faire aussi une modélisation à l’aide d’un outil informatique. Tout cela aide à mieux comprendre et anticiper la formation des produits de corrosion de l’acier par le mélange métallique liquide / This research work takes part in a global project whose aim is to understand and solve a corrosion problem of a steel called T91 caused by a liquid mixture of lead-bismuth. It presents a great interest for the nuclear community who aims to develop a new generation of reactors called ADS. This study is a contribution to the thermodynamic study of a complex system involving several elements such as Al, Bi, Pb, Fe, Cr and oxygen. More precisely, it was focused on mixtures of the following oxides Bi2O3 + PbO + Al2O3 and Bi2O3 + PbO + Fe2O3. A long experimental work had been accomplished, in which mixtures of different proportions of these oxides were prepared and heated above 600 °C for several days, followed by samples analyses by use of accurate and advanced techniques. It allowed discovering the different products formed within the different experimental conditions. The results have been modeled using a computer tool. All this allowed a better understanding and anticipating the corrosion products formation of the T91 steel by the metallic liquid

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