This thesis addresses sound production in bowed-string instruments from two perspectives: the physics of the bowed string, and bow control in performance. Violin performance is characterized by an intimate connection between the player and the instrument, allowing for a continuous control of the sound via the main bowing parameters (bow velocity, bow force and bow-bridge distance), but imposing constraints as well. In the four included studies the focus is gradually shifted from the physics of bow-string interaction to the control exerted by the player. In the first two studies the available bowing parameter space was explored using a bowing machine, by systematically probing combinations of bow velocity, bow force and bow-bridge distance. This allowed for an empirical evaluation of the maximum and minimum bow force required for the production of a regular string tone, characterized by Helmholtz motion. Comparison of the found bow-force limits with theoretical predictions by Schelleng revealed a number of striking discrepancies, in particular regarding minimum bow force. The observations, in combination with bowed-string simulations, provided new insights in the mechanism of breakdown of Helmholtz motion at low bow forces. In the second study the influence of the main bowing parameters on aspects of sound quality was analyzed in detail. It was found that bow force was totally dominating the control of the spectral centroid, which is related to the perceived brightness of the tone. Pitch flattening could be clearly observed when approaching the upper bow-force limit, confirming its role as a practical limit in performance. The last two studies were focused on the measurement of bowing gestures in violin and viola performance. A method was developed for accurate and complete measurement of the main bowing parameters, as well as the bow angles skewness, inclination and tilt. The setup was used in a large performance study. The analyses revealed clear strategies in the use of the main bowing parameters, which could be related to the constraints imposed by the upper and lower bow-force limits and pitch flattening. Further, it was shown that two bow angles (skewness and tilt) were systematically used for controlling dynamic level; skewness played an important role in changing bow-bridge distance in crescendo and diminuendo notes, and tilt was used to control the gradation of bow force. Visualizations and animations of the collected bowing gestures revealed significant features of sophisticated bow control in complex bowing patterns. / QC 20100809

Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-06-27T14:18:22Z No. of bitstreams: 1 erichardsontaroccodeoliveira.pdf: 733385 bytes, checksum: e4cec1766829e1f89c8e40c3d6528d35 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-08-07T21:05:20Z (GMT) No. of bitstreams: 1 erichardsontaroccodeoliveira.pdf: 733385 bytes, checksum: e4cec1766829e1f89c8e40c3d6528d35 (MD5) / Made available in DSpace on 2017-08-07T21:05:20Z (GMT). No. of bitstreams: 1 erichardsontaroccodeoliveira.pdf: 733385 bytes, checksum: e4cec1766829e1f89c8e40c3d6528d35 (MD5) Previous issue date: 2010-09-14 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Como são bem conhecidos; os campos quânticos estudados na TQC satisfazem o princípio de localidade segundo pontos do espaço-tempo. A eles, referem-se como campos que possuam localização do tipo-ponto ou que são puntiformemente localizados. Nesta dissertação, será feita a construção de campos quânticos livre de Dirac, com localização "tipo-string". Em contraste aos campos usuais, que vivem em ponto do espaço-tempo, estes vivem em semi-reta que começa num certo ponto do espaço de Minkowski e se estende até o infinito numa certa direção tipo-espaço. Tal localização é permitida pelos princípios da física quântica relativística, dado que os campos admitem a construção de observáveis locais. O interesse na localização tipo-string deve-se ao fato de ser uma localização menos forte, que implica um comportamento menos singular nas altas energias, apresentado pelos campos quânticos com localização tipo-ponto. Com isso apresentarão um melhor comportamento UV. Com essa localização menos forte, pode-se, então, criar mais modelos interagentes. Campos livres com localização tipo-string já foram obtidos para várias partículas [1, 2], a partir dos quais podem se fazer modelos interagentes . Para construir modelos interagentes vindos do campo livre, deve-se fazer uma análise da função de dois pontos do campo livre correspondente. Tal análise, porém, não será feita nesse trabalho, visto que não é o objetivo do estudo em questão. Nesse trabalho foi construído o campo quântico livre de Dirac com localização tipo-string, em que foram verificadas a equação de Dirac e a relação de covariância. Definiu-se sua densidade de corrente e verificou-se que esta se conserva. Por último, definiu-se a função de dois pontos para localização tipo-string, que pode ser verificada a localidade do campo tipo-string. / As is well known, quantum fields studied in TQC satisfy the second principle of locality of space-time points. To them, refer to fields that have location-point type or that are located punctate. In this dissertation, will be the construction of free quantum fields Dirac, with location-type "string". In contrast to the usual fields, living in space-time point, they live in semi-straight line beginning at a certain point in Minkowski space and extends to infinity in a certain space-like direction. This location is permitted by the principles of relativistic quantum physics, since the fields admit the construction of local observables. The interest in location-string type is due to the fact that a location is less strong, which implies a less singular behavior at high energies, described by quantum fields with point-type location. With this present an improved UV behavior. With this location less strong, we can then create more models interacting. Free fields with location-string type have been obtained for several particles [1, 2], from which they can make interacting models. To build models from the field interacting free, one must make an analysis of the function of two points corresponding free field. This analysis, however, will not be done in this work, since it is not the objective of the study. In this work we construct a quantum field-free Dirac-string type with location, which was verified in the Dirac equation and the ratio of covariance. We defined its current density and found that it is conserved. Finally, we defined the function of two points for location-string type, which can be verified the location of the string-type field.

The efficiency of modern search engines depends on how well they present typo-corrected results to a user while typing. So-called fuzzy type-ahead search combines fuzzy string matching and search-as-you-type functionality, and creates a powerful tool for exploring indexed data. Current fuzzy type-ahead search algorithms work well on small data sets, but for big data of social networking services such as Facebook, e-commerce sites such as Amazon, or media streaming services such as YouTube, responsive fuzzy type-ahead search remains a great challenge. This thesis describes a method that enables responsive type-ahead search combined with fuzzy string matching on big data by keeping the search time optimal for human interaction at the expense of lower accuracy for less popular records when a query contains typos. This makes the method effective for e-commerce and media services where the popularity of search terms is a result of human behaviour and thus often follow a power-law distribution. / Effektiviteten hos moderna sökmotorer beror på hur väl de presenterar rättstavade resultat för en användare medan en sökning skrivs. Så kallad fuzzy type-ahead sök kombinerar approximativ strängmatchning och sök-medan-du-skriver funktionalitet, vilket skapar ett kraftfullt verktyg för att utforska data. Dagens algoritmer för fuzzy type-ahead sök fungerar väl för små mängder data, men för data i storleksordningen “big data” från t.ex sociala nätverkstjänster så som Facebook, e-handelssidor så som Amazon, eller media tjänster så som YouTube, är en responsiv fuzzy type-ahead sök ännu en stor utmaning. Denna avhandling beskriver en metod som möjliggör responsiv type-ahead sök kombinerat med approximativ strängmatchning för big data genom att hålla söktiden optimal för mänsklig interaktion på bekostnad av lägre precision för mindre populär information när en sök-förfrågan innehåller felstavningar. Detta gör metoden effektiv för e-handel och mediatjänster där populariteten av sök-termer är ett resultat av mänskligt beteende vilket ofta följer en potens-lag distribution.

We show that, for any tubular algebra, the lattice of pp-definable subgroups of the direct sum of all indecomposable pure-injective modules of slope r has m-dimension 2 if r is rational, and undefined breadth if r is irrational- and hence that there are no superdecomposable pure-injectives of rational slope, but there are superdecomposable pure-injectives of irrational slope, if the underlying field is countable.We determine the pure-injective hull of every direct sum string module over a string algebra. If A is a domestic string algebra such that the width of the lattice of pp-formulas has defined breadth, then classify "almost all" of the pure-injective indecomposable A-modules.

As a little boy, Dmitriĭ Dmitrievich Shostakovich pressed his ear against the wall to hear his neighbors play chamber music. He matured into one of the most prominent Soviet era composers. While the majority of academic interest Shostakovich centers on his symphonic works, his string quartets provide a window into a more intimate facet of Shostakovich’s life. This thesis explores first, why Shostakovich turned to the string quartet after some of the most fearful years of his life: his demise and rise after the scathing Pravda letter that all but threatened his life. Second, this thesis analyzes three of Shostakovich’s String Quartets: No. 1, No. 8, and No. 15. String Quartet No. 1, despite its simplicity, illuminates tender expressivity. Following years of intense artistic and personal scrutiny, Shostakovich sought an escape into an aural world of innocence. However, the quartet proves more complex than its surface suggests. Obscured harmonic complexities, intimate dialogue between instruments, and subtle recollection of prior movements lend the quartet a deeper meaning than its aural simplicity suggests. Decades later, amidst personal crisis, Shostakovich turned to the quartet, again. Composed in 1960, the year of his invocation into the communist party, String Quartet No. 8 demonstrates how Shostakovich utilized the string quartet as an avenue for personal self-expression. The intertwining of his musical signature with constant self-quotations and allusions confirms the deep, personal reflection the quartet provided Shostakovich. This study recounts the quotations previously uncovered by David Fanning, but goes beyond identification and relates the content of the quotations to Shostakovich’s emotional turmoil at the time of his party invocation. Finally, enduring anguishing physical pain and facing death, Shostakovich turned to the string quartet at the end of his life. String Quartet No. 15 provided Shostakovich an external outlet for his internal dialogue on death. Sentiments of meditation, fury, resistance, anguish, and resignation musically intertwine during Shostakovich’s longest and most painful string quartet. This study demonstrates how Shostakovich used the string quartet as a medium for deeper self-expression.

Dans cette thèse, nous présentons des constructions explicites de la correspondance AdS/CFT dans le contexte de la théorie des cordes de type II. Ces constructions sont visées à mieux comprendre aspects de la physique nonperturbative de théories des champs superconformes à d = 6,5,4 dimensions. Dans la première partie de la thèse nous introduisons les systèmes de NS5-Dp-D(p+2)-branes de Hanany-Witten, au moyen desquels on peut construire théories des champs avec 8 supercharges. Quand p = 6, le système de NS5-D6-D8-branes permet de construire théories des champs superconformes à 6 dimensions, caractérisées par des multiplets tenseur, vecteur et hypermultiplets de la superalgèbre chirale N = (1,0). Ces théories sont décrites par des «quivers» linéaires; nous analysons en détails leurs propriétés. Dans le cadre de la correspondance AdS/CFT, une théorie superconforme à (d - 1) dimensions décrit la même physique qu’un vide de la théorie des cordes de type II compactifiée sur un espace-temps Anti-de Sitter à d dimensions (AdSd). Par le biais de la géométrie complexe généralisée nous reformulons les équations qui doivent être résolues pour trouver ces vides AdS. La seconde partie contient les contributions originales. Nous présentons une classification exhaustive des vides de la théorie des cordes de type II compactifiée sur AdS7. En type IIB, il n’y a aucun vide; en type IIA massif, nous construisons une nouvelle classe infinie (et analytique) de vides. L’espace interne est topologiquement une 3-sphere, déformée par la présence de D6 et D8-branes. Les isométries de cet espace réalisent la symétrie R des théories superconformes N = (1,0) à 6 dimensions. Nos vides AdS7 sont les duaux holographiques de ces dernières, et peuvent être obtenus par une limite près de l’horizon des systèmes de NS5-D6-D8-branes. Le second résultat est la construction d’une classe infinie de vides analytiques AdS5 en type IIA massif. L’espace interne est le produit d’une 3-sphere par une surface de Riemann. Les isométries de cet espace réalisent la symétrie R des théories superconformes N = 1 à 4 dimensions, dont nos vides AdS5 sont les duaux holographiques. Nous décrivons une bijection entre ces derniers et les vides AdS7 susmentionnés. L’interprétation holographique indique que les théories N = 1 à 4 dimensions sont obtenues en compactifiant celles N = (1,0) à 6 dimensions sur la même surface de Riemann. Troisièmement, nous réduisons à deux equations différentielles le problème de classification des vides AdS6 en type IIB duaux à théories superconformes N = 1 à 5 dimensions. L’espace interne de ces vides contient une 2-sphere, réalisant la symétrie R des ces dernières. / In this thesis we present explicit constructions of the AdS/CFT correspondence obtained from type II string theory. These constructions are aimed at studying aspects of the nonperturbative physics of 6d, 5d, 4d SCFTs. In the first part we introduce NS5-Dp-D(p+2) Hanany--Witten brane systems, capable of engineering field theories with 8 Q supercharges. In particular, when p=6, the NS5-D6-D8 brane systems are known to engineer 6d SCFT featuring tensor, vector and hypermultiplets of the chiral N=(1,0) superalgebra. These theories can be described by linear quivers. We analyze in detail their properties. In AdS/CFT, the same physics can be equivalently described by a (d-1)-dimensional SCFT and by type II string theory compactified on a d-dimensional AdS space (AdSd), giving rise to a so-called AdSd vacuum. By using techniques derived from generalized complex geometry we reformulate the equations that need to be satisfied in order to find these AdS vacua. The second part of the thesis contains the original contributions. We present a full classification of vacua of type II string theory compactified on AdS7. In type IIB there are no such vacua; in massive type IIA, we construct a new infinite class of (analytic) vacua. The internal space is topologically a three-sphere, deformed by the presence of D6 and D8-branes. The isometries of this space realize the R-symmetry of the 6d (1,0) SCFTs. Our AdS7 vacua are the holographic duals of the latter, and can be obtained via a near-horizon limit of the NS5-D6-D8 brane systems. The second result is the construction of an infinite class of analytic AdS5 vacua of massive IIA. The internal space is a fibration of a (distorted) three-sphere over a Riemann surface. Its isometries realize the R-symmetry of putative 4d N=1 SCFTs, holographically dual to our AdS5 vacua. We describe a universal one-to-one map between the latter and the aforementioned AdS7 vacua. The natural interpretation of this is that the 4d N=1 SCFTs can be obtained by compactifying (in a twisted way) the 6d (1,0) ones on the same Riemann surface. In the third and last part, we reduce to two PDEs the classification problem of AdS6 vacua of type IIB supergravity, which should be the holographic duals to 5d N=1 SCFTs. The latter can be engineered by webs of (p,q)-fivebranes in type IIB string theory. The internal space of the AdS6 vacua is given by a fibration of a round two-sphere over a two-dimensional surface; the isometries of the fibers should realize the R-symmetry of the dual field theories. / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

Given a D-brane background in string theory (or equivalently boundary conditions in a two dimensional conformal field theory), classical solutions of open string field theory equations of motion are conjectured to describe new D-brane backgrounds (boundary conditions). In this thesis we study these solutions in the bosonic open string field theory using the level truncation approach, which is a numerical approach where the string field is truncated to a finite number of degrees of freedom. We start with a review of the theoretical background and numerical methods which are needed in the level truncation approach and then we discuss solutions in several different back- grounds. First we discuss universal solutions, which do not depend on the open string back- ground, then we analyze solutions of the free boson theory compactified on a circle or on a torus, then marginal solutions in three different approaches and finally solutions in theories which in- clude the A-series of Virasoro minimal models. In addition to known D-branes, we find so-called exotic solutions which potentially describe yet unknown boundary states. 1

String matching algorithms are the algorithms used to search through different types of text in search of a certain pattern. Many of these algorithms achieve their impressive performance by analysing the pattern and saving that information. That information is then continuously used during the searching phase to know what parts of the text can be skipped. One such algorithm is the Berry-Ravindran. The Berry-Ravindran checks the two characters past the current try for a match and sees if those characters exist in the pattern. This thesis compares the Berry-Ravindran algorithm to new versions of itself that check three and four characters instead of two, along with the Boyer-Moore algorithm. Checking more characters improves the amount of the text that can be skipped by reducing the number of attempts needed but exponentially increases the pre-processing time. The improved performance in attempts does not necessarily mean a faster run-time because of the increased pre-processing time. The variable impacting the pre-processing time the biggest is the size of the alphabet that the text uses. This is researched by testing these algorithms with patterns ranging from 4 to 100 characters long on two different data sets. Protein data which has an alphabet size of 27 and DNA data which has an alphabet size of 4.

Während das lokale Verhalten von geodätischen Kurven in Riemannschen Mannigfaltigkeiten gut verstanden ist, ist es wesentlich schwieriger das globale Verhalten dieser Kurven zu untersuchen. Die vorliegende Dissertation greift daher zwei Themen heraus, in denen globale Eigenschaften von Geodätischen mit Invarianten Riemannscher Mannigfaltigkeiten in Verbindung gebracht werden. Zum Einen wird das Koprodukt der String-Topologie untersucht. Diese auf der Homologie des freien Schleifenraumes einer geschlossenen Mannigfaltigkeit definierte Abbildung kann geometrisch verstanden werden als Operation, welche Schleifen mit Selbstschnitten in zwei Teile zerschneidet. In der vorliegenden Dissertation wird gezeigt, dass das nicht-triviale Verhalten einer Iteration des Koprodukts genutzt werden kann um die Multiplizitäten bestimmter geschlossener Geodätischer abzuschätzen. Zudem wird das Koprodukt für bestimmte Klassen von Mannigfaltigkeiten untersucht. Der freie Schleifenraum einer Lie-Gruppe ist homömorph zum Produkt der Gruppe mit ihrem Schleifenraum bezüglich eines Punktes. Dies induziert einen Isomorphismus in Homologie und es wird gezeigt, dass sich das Koprodukt unter diesem Isomorphismus gut verhält. Durch das Nutzen expliziter Zykel kann man zudem sehen, dass das Koprodukt für kompakte, einfach zusammenhängende Lie-Gruppen von höherem Rang trivial ist. Anschließend wird das Koprodukt für den komplexen und den quaternionisch projektiven Raum berechnet. Hierfür werden wieder explizite Zykel genutzt, auf die das Koprodukt in gewisser Weise zurückgezogen werden kann. Im zweiten Teil der Dissertation wird die geodätische Komplexität einer vollständigen Riemannschen Mannigfaltigkeit untersucht. Die geodätische Komplexität ist eine ganzzahlige Isometrie-Invariante von vollständigen Riemannschen Mannigfaltigkeiten, welche man als Abstraktion des Problems der geodätischen Bewegungsplanung verstehen kann. Es stellt sich heraus, dass die geodätische Komplexität stark vom Schnittort einer vollständigen Riemannschen Mannigfaltigkeit abhängt. In der vorliegenden Dissertation wird die Struktur des Schnittorts von homogenen Riemannschen Mannigfaltigkeiten genutzt um eine obere Schranke an die geodätische Komplexität solcher Räume zu erhalten. Diese Abschätzung liefert insbesondere für Lie-Gruppen gute Resultate und kann genutzt werden um die geodätische Komplexität von zweidimensionalen flachen Tori und von Berger-Sphären zu bestimmen. Eine andere obere Schranke für die geodätische Komplexität erhält man durch das Betrachten von sogenannten gefaserten Zerlegungen des Schnittorts. In der vorliegenden Dissertation werden diese Zerlegungen eingeführt und es wird gezeigt, dass die Schnittorte aller kompakten irreduziblen einfach zusammenhängenden symmetrischen Räume solch eine Zerlegung zulassen. Dieses Resultat kann dann genutzt werden um eine Abschätzung der geodätischen Komplexität dieser Räume zu erhalten. Insbesondere kann die geodätische Komplexität vom komplexen und vom quaternionisch projektiven Raum bestimmt werden. Dieser zweite Teil der Dissertation geht aus einem gemeinsamen Projekt mit Stephan Mescher hervor. / While the local behavior of geodesics in Riemannaian manifolds is well understood, it is much harder to study the global behavior of such curves. In this thesis we study two problems which connect global properties of geodesics to invariants of Riemannian manifolds. Firstly, we study the string topology coproduct. This is a map on the homology of the free loop space of a closed manifold and can be understood as an operation that cuts loops with self-intersections into two parts. It is shown in the thesis that the non-trivial behavior of an iterate of the coproduct can be used to estimate the multiplicity of certain closed geodesics. Furthermore, we study the coproduct for particular classes of manifolds. The free loop space of a Lie group is homeomorphic to the product of the group with its based loop space. This induces an isomorphism in homology and we show that the coproduct behaves well with respect to this isomorphism. By considering explicit cycles one can show that the string topology coproduct is trivial for compact simply connected Lie groups of higher rank. Moreover, the string topology coproduct is computed explicitly for complex and quaternionic projective space again by using certain explicit cycles. In the second part of the thesis we study the geodesic complexity of complete Riemannian manifolds. Geodesic complexity is a numerical isometry invariant of complete Riemannian manifolds and can be understood as an abstraction of the geodesic motion planning problem. It turns out that the geodesic complexity of a complete Riemannian manifold highly depends on the cut locus of that manifold. We use the structure of the cut loci of homogeneous Riemannian manifolds to obtain an upper bound on the geodesic complexity of these spaces. This bound turns out to work very well for Lie groups and we use it to compute the geodesic complexity of flat two-dimensional tori and of Berger spheres. Another upper bound on geodesic complexity can be obtained by considering fibered decompositions of the total cut locus. In this thesis we introduce the concept of a fibered decomposition and show that the cut loci of compact irreducible simply connected symmetric spaces admit such decompositions. This result can then be used to prove an upper bound on the geodesic complexity of these spaces. In particular we determine the geodesic complexity of complex and quaternionic projective space. This second part of the thesis is based on joint work with Stephan Mescher.

<p>The purpose of this thesis is twofold and motivated by recent developments in string theory and extra dimensional models. The first objective is to describe the development and progress in the codimension-2 brane paradigm as a potential cosmological scenario. Secondly, it presents the Antide Sitter/Conformal Field Theory (AdS/CFT) conjecture, also known as holography, as a tool for calculating physical quantities in condensed matter system and goes on to model the quantum Hall effect. We first describe the initial development of treating back-reaction in codimension-2 branes systems with a scalar and gauge field. The purpose of this is to examine the low-energy effective dynamics on the brane. Furthermore, applications are then explored for D7-branes in F-theory as well as D3-branes in large extra dimensional scenarios explored as a model for the cosmological constant problem. The result of this work is that the higher and lower dimensional scenarios are consistent with each other once brane back-reaction is considered in these models. This work led to a number of future works one of which is in relation to the cosmological constant problem. While the subsequent work is beyond the scope of this thesis, we present a picture and further references for the reader. The larger, later, portion of this thesis introduces the concept of holography, its origins, and the applicability to condensed matter systems. Furthermore, we discuss the applicability in particular to the quantum Hall effect (QHE) and present a model in the holographic language that correctly reproduces some of the physics of the QHE. This includes a paper in which we introduce the model, along with demonstration of symmetry properties and conductivity calculations, as well as a paper which examines the finite size scaling behaviour of the model. As a benefit to the reader, we present a `starter edition guide' to the AdS/CFT dictionary preceding these papers for non-experts such that this thesis is self-contained. The upshot is that these avenues of work, in particular quantum Hall-ography, have been very successful in modeling physics using tools originally developed by string theory. As such, it provides support for string theory as a model and framework, as well as providing more opportunities for future predictions of physical quantities.</p> / Doctor of Philosophy (PhD)