Orientador: Horatiu Nastase / Resumo: Nesta tese, discutimos três modelos cosmológicos que são baseados direta ou indiretamente em ideias advindas de teoria das cordas. Depois de uma revisão geral de cosmologia em teoria das cordas, um resumo de cosmologia e teoria das cordas é apresentado, com ênfase nos conceitos fundamentais e teóricos. Então descrevemos como o acoplamento camaleônico pode potencialmente afetar as predições de inflação cósmica com campo único, com tratamento cuidadoso dos modos de perturbação cosmológica adiabáticos e de entropia. Além disso uma nova abordagem para a dualidade-T em soluções cosmológicas de supergravidade bosônica é discutida no contexto de teoria dupla de campos. Por fim, propomos uma nova prescrição para o mapa holográfico em cosmologia que pode ser usado para conectar modelos fundamentais de cosmologia holográfica com outras abordagens fenomenológicas. / Doutor

<p>Researchers tend to use their own or favourite gene names in scientific literature, even though there are official names. Some names may even be used for more than one gene. This leads to problems with ambiguity when automatically mining biological literature. To disambiguate the gene names, gene normalization is used. In this thesis, we look into an existing gene normalization system, and develop a new method to find gene candidates for the ambiguous genes. For the new method a lexicon is created, using information about the gene names, symbols and synonyms from three different databases. The gene mention found in the scientific literature is used as input for a search in this lexicon, and all genes in the lexicon that match the mention are returned as gene candidates for that mention. These candidates are then used in the system's disambiguation step. Results show that the new method gives a better over all result from the system, with an increase in precision and a small decrease in recall.</p>

Thesis (Ph. D.)--University of Chicago, Dept. of Physics, June 1999. / Includes bibliographical references. Also available on the Internet.

Cette thèse intitulée « Studies of fractional D-branes in the gauge/gravity correspondence & Flavored Chern-Simons quivers for M2-branes » se place dans le cadre de la théorie des cordes, en physique théorique. Elle consiste en une introduction suivie de deux parties. Dans l'introduction sont résumés les différents outils de théorie des cordes qui seront utilisés. La première partie étudie des théories de type quiver en 3+1 dimensions et leur dual gravitationnel, qui découlent de la considération de D-branes fractionnaires vivant sur des espaces possédant des singularités en codimension complexe un. La thèse principale de cette partie est que la solution de supergravité de Bertolini et al. 2001 and Polchinski 2001 pour des branes de type N=2 a une interprétation dans la théorie des champs de type quiver duale comme un groupe de renormalisation de type cascade qui résulte d'un choix particulier sur la branche de Coulomb de la théorie. Cette compréhension nouvelle permet d'étudier des solutions de supergravité plus générales. Elle donne aussi une plus grande compréhension des branes N=2 dans des contextes avec seulement une supersymmétrie N=1. La second partie de la thèse étudie les quivers de type Chern-Simons, récemment apparus dans la littérature, décrivant des théories en dimension 2+1, qui sont conjecturé dual à des solutions de M-théorie. Il est montré que des théories plus générales que des quivers, possédant également des champs dans la représentation fondamentale des groupes de jauges, permettent la description de M2-branes sur des espaces possédant des singularités de dimension complexe deux, du moins du point de vue de la structure complexe, dans le cas où seules 4 supercharges sont préservées. La thèse principale est que la considération des operateurs monopoles diagonaux dans la théorie de champs N=2 supersymmétrique en 2+1 dimensions, plus une relation entre ces opérateurs proposée comme conjecture, permettent de reproduire l'espace des modules d'une M2-brane sur n'importe quelle géométrie torique ayant des singularités en codimension complexe deux.

Researchers tend to use their own or favourite gene names in scientific literature, even though there are official names. Some names may even be used for more than one gene. This leads to problems with ambiguity when automatically mining biological literature. To disambiguate the gene names, gene normalization is used. In this thesis, we look into an existing gene normalization system, and develop a new method to find gene candidates for the ambiguous genes. For the new method a lexicon is created, using information about the gene names, symbols and synonyms from three different databases. The gene mention found in the scientific literature is used as input for a search in this lexicon, and all genes in the lexicon that match the mention are returned as gene candidates for that mention. These candidates are then used in the system's disambiguation step. Results show that the new method gives a better over all result from the system, with an increase in precision and a small decrease in recall.

With limited road infrastructure and increasing number of vehicles on the road, an intelligent transport system is needed to increase the throughput in traffic and minimize traffic jams in highly populated areas. The purpose of this project is to design and implement a control system that is capable of driving and following the preceding vehicle autonomously in the longitude direction only. The vehicle is also equipped with a vehicle to vehicle communication unit. With this information, all vehicles on the road can communicate with each other and are able to achieve shorter distances between vehicles and damp any disturbance caused by upstream traffic. A general structure on Cooperative Adaptive Cruise Control (CACC) is created by studying the research from The Netherlands Organization for Applied Scientific Research (TNO). A string stability criterion is used to determine if the system is suitable of driving in a platoon, where a string of vehicles are following a lead vehicle. This system is then implemented in a Volvo S60 and has participated in the 2011 Grand Cooperative Driving Challenge hosted in The Netherlands. The results show that the system has ability to increase throughput and damp disturbance on the upstream traffic by communicating with the other vehicles ahead. The system is also robust and simple enough to earn the 2nd place in the competition. / Grand Cooperative Driving Challenge

Henry Cowell (1897-1965), American composer in 20th century, is the first who proposed the concept of tone clusters and placed many new techniques in his piano music. Innovative music theories and unique thoughts were displayed in his compositions and critiques. For developing both new visual and audio effects of piano music, Cowell played tone clusters with arms, palms, and fists, and also played strings inside piano to give new gesture and timbre of piano. This thesis is divided into three parts besides introduction and conclusion. The first part describes the origin and development of new piano techniques in the 20th century. The second part investigates Cowell¡¦s compositional career, compositional methods and thoughts for piano music. The third part analyzes ways of performing tone clusters and strings in Cowell¡¦s solo piano pieces with new techniques. Through analyzing these particular techniques, the compositional methods and uniqueness of Cowell¡¦s piano music could be understood. In the meanwhile, the performers will pay more attention to avoid performing injuries and damaging pianos.

The String quartet, a representative genre in the chamber music, was emerged in the Pre-Classical era, a period that the trio sonata was about at end of its development. The musical characteristics of the string quartets and trio sonatas were closely connected. The present study centers on the transitional stylistic features of the two genres in order to classify the initial stage for the development of the string quartet. This research focuses on the analysis of works of the trio sonata and the string quartet which were written during the transitional period. The thesis consists of three main chapters, in addition to the introduction and conclusion. Chapter one discusses the background of the string chamber music in Pre-Classical era. Chapter two describes the development of the trio sonata from 1720 to 1770. Chapter three concentrates on the musical characteristics of early development of the string quartets. The works of the trio sonata in mid-eighteenth century had already been characterized by the treble-dominated homophonic texture. In addition, the viola replaced the basso continuo and the chordal texture in the inner voices that led to the result in the change of the texture of trio sonata to the string quartet. The emergence of plentiful social occasions in Pre-Classical era required a large number of the chamber music. The string quartets were brought during this crucial moment. The composers at this stage tried a variety of tastes of styles and eventually, the mixed characteristics evolved into a natural, elegance, balanced, and symmetrical style and led the string quartet to its maturity.

The eigenvalue gaps and eigenvalue ratios of the Sturm-Liouville systems have been studied in many papers. Recently, Lavine proved an optimal lower estimate of first eigenvalue gaps for Schrodinger operators with convex potentials. His method uses a variational approach with detailed analysis on different integrals. In 1999, (M.J.) Huang adopted his method to study eigenvalue ratios of vibrating strings. He proved an optimal lower estimate of first eigenvalue ratios with nonnegative densities. In this thesis, we want to generalize the above optimal estimate. The work of Ashbaugh and Benguria helps in attaining our objective. They introduced an approach involving a modified Prufer substitution and a comparison theorem to study the upper bounds of Dirichlet eigenvalue ratios for Schrodinger operators with nonnegative potentials. It is interesting to see that the counterpart of their result is also valid. By Liouville substitution and an approximation theorem, the vibrating strings with concave and positive densities can be transformed to a Schrodinger operator with nonpositive potentials. Thus we have the generalization of Huang's result.

The string quartet is one of the most important genre since the Classical period, especially beginning with the works of Joseph Haydn. The abundance of quantity and internal proficiency of the string quartet reach its highest point in late period of Beethoven¡¦s work. A few composers treated the string quartets as priority genre in their entire creative life before Bart&#x00F3;k composed a series of six string quartets which included his musical thoughts and spiritual progression spreading in the different stages during his lifetime. The purpose of the study is to discuss the various characteristics in every stage creative processes and techniques of Bart&#x00F3;k¡¦s string quartets. The discussion of this thesis consists of four chapters. Chapter one the background of twentieth-century such as global influence of politics, economy, arts activity. During the wars, Bart&#x00F3;k concentrated on folk songs that is the most powerful change his career and influenced the way he composed. The discussions of the chapter two include the intergrade and combine folk songs of the Western traditional music and East Europe which occupied his great creative changes, and the differences of traditional string instruments usage. Chapter three elaborates the content of six quartets which is the manipulation of the logical and unity of Bart&#x00F3;k¡¦s use of motive, theme, melody, interval, harmony or instrumental usage. Furthermore, a popular topic called golden section is introduced from those integral elements. Chapter four concludeds the study with the discussion of which the composer was under the influence of the music development in Hungary and his contribution to the history of western music. Not only Bart&#x00F3;k¡¦s six string quartets are one of the most important works in twentieth-century string literature, but also they are continuation of Beethoven¡¦s late six string quartets. Bart&#x00F3;k devoted himself to musical materials from Western and Eastern Europe. As this point of view, Bart&#x00F3;k¡¦s six string quartets are the finest expression of his heart. No matter what composition skills he used or as a humanism, it is no doubt that B&#x00E9;la Bart&#x00F3;k made his great contribution in the field of string quartets.