Through a comprehensive analysis of literary and documentary material from 1270–1500, this study offers insights into the history and significance of the late medieval string instrument known as the gittern in Western Europe. Source criticism and hermeneutics form the basis of the critical reading of the nearly hundred sources. Through these, a more refined history of the instrument is suggested, focusing on social, symbolic and musical change throughout the period. The gittern is shown to have been an instrument predominately used in noble and royal milieus for half a century before being more widely played among all ranks of society. When its popularity faded in the 15th century, it became a symbol of nostalgia. The sound and playing techniques of the gittern were well suited for the music of the late 14th century, and the decline in use was simultaneous to the developments of new genres and compositional techniques where other sounds were sought.

This thesis sets out to investigate new notation symbols, systems, and string techniques in some one hundred 20th century string quartets, selected from a variety of composers. The analysis includes compositions that have, through contemporary aesthetic ideals, extended musical and technical resources and stimulated the development of compositional methods in such a way as to influence later works in the genre. k The thesis divided into two parts : Histoiy and Research Part One is a brief history of 20th century music, and includes the development o f the string quartet from earliest times up to the mid-century. Part Two researches string techniques and notation from the turn of the century up to 1990. The historical perspective demonstrates that after World War n, with the emergence o f the electronic age and a changing social and intellectual climate, traditional concepts were being challenged. Composers facing the dilemma affecting music in general, and the string quartet in particular, had to adapt to radically developing techniques and styles. Sounds and syntax o f a different type were initially, but unsuccessfully, sought to unify the divergent thinking o f the time. Ultimately, the developmental paths took shape from the problem itself and different approaches emerged to master the multi-faceted dimensions available to composers. Part Two investigates music syntax from the viewpoint of recording new symbols, notation systems and string techniques. Quartets of the first half of the century show that both the dissolution and the extension o f traditional processes were contained, importantly, within the continued use of conventional notation. The impact and significance of these quartets within the context of 20th century development cannot be ignored. However, the quartets researched post-1960 demonstrate that composers have enlarged all parameters of the genre through the extension of traditional resources and by radical innovation. This research demonstrates that the emergence of new symbols and string techniques in the second half of the century has been largely on an arbitrary basis. Nevertheless^ broad classification of these elements is undertaken. / Art History, Visual Arts & Musicology / D.Mus. (Musicology)

This thesis sets out to investigate new notation symbols, systems, and string techniques in some one hundred 20th century string quartets, selected from a variety of composers. The analysis includes compositions that have, through contemporary aesthetic ideals, extended musical and technical resources and stimulated the development of compositional methods in such a way as to influence later works in the genre. k The thesis divided into two parts : Histoiy and Research Part One is a brief history of 20th century music, and includes the development o f the string quartet from earliest times up to the mid-century. Part Two researches string techniques and notation from the turn of the century up to 1990. The historical perspective demonstrates that after World War n, with the emergence o f the electronic age and a changing social and intellectual climate, traditional concepts were being challenged. Composers facing the dilemma affecting music in general, and the string quartet in particular, had to adapt to radically developing techniques and styles. Sounds and syntax o f a different type were initially, but unsuccessfully, sought to unify the divergent thinking o f the time. Ultimately, the developmental paths took shape from the problem itself and different approaches emerged to master the multi-faceted dimensions available to composers. Part Two investigates music syntax from the viewpoint of recording new symbols, notation systems and string techniques. Quartets of the first half of the century show that both the dissolution and the extension o f traditional processes were contained, importantly, within the continued use of conventional notation. The impact and significance of these quartets within the context of 20th century development cannot be ignored. However, the quartets researched post-1960 demonstrate that composers have enlarged all parameters of the genre through the extension of traditional resources and by radical innovation. This research demonstrates that the emergence of new symbols and string techniques in the second half of the century has been largely on an arbitrary basis. Nevertheless^ broad classification of these elements is undertaken. / Art History, Visual Arts and Musicology / D.Mus. (Musicology)

Dissertation submitted in partial compliance with the requirements for the Master’s Degree in Technology: Chiropractic, Durban University of Technology, 2010. / Background: Professional orchestral string musicians are exposed to many physical and psychological stressors due to demands placed on them from playing their instruments. The prevalence of performance-related musculoskeletal disorders (PRMD’s) in this highly skilled group of individuals has been investigated internationally, consistently showing a high injury rate. There is however, a paucity of literature documenting the prevalence of musculoskeletal injuries in South African professional orchestral string players. It is hypothesized that South African trained orchestral string musicians may be at a greater risk for PRMD development due to the unique training and performance environments encountered in this country. Objectives: This study aimed to determine the demographic and injury profile; prevalence rate of current injury and risk factors for musculoskeletal injury in South African professional orchestral string musicians. Method: The study utilized a self administered quantitative questionnaire distributed to all string players in the three professional orchestras in South African in a semi-supervised fashion. SPSS version 15.0 (SPSS Inc., Chicago, Illinois, USA) was used to analyze the data. A p value < 0.05 was considered as statistically significant. iv v Results: There were 27 respondents, with the average participant being a Caucasian, right handed, non-smoking female, 37.11 years of age, 1.5631 meters tall, with a weight of 62.96 kilograms (BMI = 25.768) who exercised regularly (primarily in the gym). A bachelors degree in Music was the most commonly awarded qualification, obtained between the years 2000 and 2009, from a University outside of the Republic of South Africa. The prevalence of PRMD’s in the sample was 63% (n = 17), with a 95% confidence interval of 42.4% to 80.6%.In this study there was a high rate of injury (6.53 PRMD’s per player over a 12 month period), equating to 111 reported injuries in a population of 27 string players. The upper back (defined as the area between the shoulder blades) was the most commonly injured part of the body (77.8%, n = 21), followed by the upper extremity, mainly the shoulder (70.4%, n = 19). No statistically significant relationships were found in determining and confirming expected risk factors in the string players. Conclusion: Professional orchestral string musicians in South Africa suffer from a high rate of injury which is comparable to international studies of the same nature

No description available.

On fait l'analyse de la dynamique nonlinéaire d'une colonne de forage avec modélisation d'incertitudes. Une colonne de forage est une structure flexible mince qui tourne et fore des roches en cherchant du pétrole. Un modèle mathématique-mécanique est développeé pour cette structure en incluant de l'interaction fluide-structure, des impact, des nonlinéarités géométriques, et de l'interaction tête de la colonne-roche. Les équations de mouvement sont déduites, puis le système est discretisé par la méthode des éléments finis, et un code numérique est développeé pour les simulations numériques avec le logiciel MATLAB. Les modes normaux de la dynamique à la configuration précontrainte sont utilisés pour construire un modèle reduit pour le système. L'approche probabiliste nonparamétrique, qui est capable de prendre en compte les incertitude des paramètres du système et aussi les incertitude de modèle, est utilisée. Les fonctions densités de probabilité liées aux variables aléatoire sont construites par la méthode du Maximum d'Entropie et la réponse stochastique du système est calculée en utilisant la méthode de Monte Carlo. Une nouvelle approche pour prendre en compte des incertitudes de modèle dans une équation constitutive nonlinéaire (interaction tête de la colonne-roche) est développeé avec l'approche probabiliste nonparamétrique. La méthode du maximum de vraisemblance et la réduction statistique dans le domaine de la fréquence (Analyse de composantes principales) sont utilisés pour identifier le modèle probabiliste de l'interaction tête de la colonne-roche. Finalement, un problème d'optimisation robuste est analysé de façon à trouver les paramètres opérationnels du système qui maximise sa performance et respectent les limites d'intégrités du système, comme fatigue et instabilitée / This thesis analyzes the nonlinear dynamics of a drill-string including uncertainty modeling. A drill-string is a slender flexible structure that rotates and digs into the rock in search of oil. A mathematical-mechanical model is developed for this structure including fluid-structure interaction, impact, geometrical nonlinearities and bit-rock interaction. After the derivation of the equations of motion, the system is discretized by means of the finite element method and a computer code is developed for the numerical computations using the software MATLAB. The normal modes of the dynamical system in the prestressed configuration are used to construct a reduced order model for the system. To take into account uncertainties, the nonparametric probabilistic approach, which is able to take into account both system-parameter and model uncertainties, is used. The probability density functions related to the random variables are constructed using the maximum entropy principle and the stochastic response of the system is calculated using the Monte Carlo method. A novel approach to take into account model uncertainties in a nonlinear constitutive equation (bit-rock interaction model) is developed using the nonparametric probabilistic approach. To identify the probabilistic model of the bit-rock interaction model, the maximum likelihood method together with a statistical reduction in the frequency domain (using the Principal Component Analysis) is applied. Finally, a robust optimization problem is performed to find the operational parameters of the system that maximizes its performance, respecting the integrity limits of the system, such as fatigue and instability

Travail réalisé en cotutelle avec l'université Paris-Diderot et le Commissariat à l'Energie Atomique sous la direction de John Harnad et Bertrand Eynard. / Cette thèse traite des aspects géométriques et d'intégrabilité associés aux modèles de matrices aléatoires. Son but est de présenter diverses applications des modèles de matrices aléatoires allant de la géométrie algébrique aux équations aux dérivées partielles des systèmes intégrables. Ces différentes applications permettent en particulier de montrer en quoi les modèles de matrices possèdent une grande richesse d'un point de vue mathématique. Ainsi, cette thèse abordera d'abord l'étude de la jonction de deux intervalles du support de la densité des valeurs propres au voisinage d'un point singulier. On montrera plus précisément en quoi ce régime limite particulier aboutit aux équations universelles de la hiérarchie de Painlevé II des systèmes intégrables. Ensuite, l'approche des polynômes (bi)-orthogonaux, introduite par Mehta pour le calcul des fonctions de partition, permettra d'énoncer des problèmes de Riemann-Hilbert et d'isomonodromies associés aux modèles de matrices, faisant ainsi le lien avec la théorie de Jimbo-Miwa-Ueno. On montrera en particulier que le cas des modèles à deux matrices hermitiens se transpose à un cas dégénéré de la théorie isomonodromique de Jimbo-Miwa-Ueno qui sera alors généralisé. La méthode des équations de boucles avec ses notions centrales de courbe spectrale et de développement topologique permettra quant à elle de faire le lien avec les invariants symplectiques de géométrie algébrique introduits récemment par Eynard et Orantin. Ce dernier point fera également l'objet d'une généralisation aux modèles de matrices non-hermitien (beta quelconque) ouvrant ainsi la voie à la ``géométrie algébrique quantique'' et à la généralisation de ces invariants symplectiques pour des courbes ``quantiques''. Enfin, une dernière partie sera consacrée aux liens étroits entre les modèles de matrices et les problèmes de combinatoire. En particulier, l'accent sera mis sur les aspects géométriques de la théorie des cordes topologiques avec la construction explicite d'un modèle de matrices aléatoires donnant le dénombrement des invariants de Gromov-Witten pour les variétés de Calabi-Yau toriques de dimension complexe trois utilisées en théorie des cordes topologiques. L'étendue des domaines abordés étant très vaste, l'objectif de la thèse est de présenter de façon la plus simple possible chacun des domaines mentionnés précédemment et d'analyser en quoi les modèles de matrices peuvent apporter une aide précieuse dans leur résolution. Le fil conducteur étant les modèles matriciels, chaque partie a été conçue pour être abordable pour un spécialiste des modèles de matrices ne connaissant pas forcément tous les domaines d'application présentés ici. / This thesis deals with the geometric and integrable aspects associated with random matrix models. Its purpose is to provide various applications of random matrix theory, from algebraic geometry to partial differential equations of integrable systems. The variety of these applications shows why matrix models are important from a mathematical point of view. First, the thesis will focus on the study of the merging of two intervals of the eigenvalues density near a singular point. Specifically, we will show why this special limit gives universal equations from the Painlevé II hierarchy of integrable systems theory. Then, following the approach of (bi) orthogonal polynomials introduced by Mehta to compute partition functions, we will find Riemann-Hilbert and isomonodromic problems connected to matrix models, making the link with the theory of Jimbo, Miwa and Ueno. In particular, we will describe how the hermitian two-matrix models provide a degenerate case of Jimbo-Miwa-Ueno's theory that we will generalize in this context. Furthermore, the loop equations method, with its central notions of spectral curve and topological expansion, will lead to the symplectic invariants of algebraic geometry recently proposed by Eynard and Orantin. This last point will be generalized to the case of non-hermitian matrix models (arbitrary beta) paving the way to ``quantum algebraic geometry'' and to the generalization of symplectic invariants to ``quantum curves''. Finally, this set up will be applied to combinatorics in the context of topological string theory, with the explicit computation of an hermitian random matrix model enumerating the Gromov-Witten invariants of a toric Calabi-Yau threefold. Since the range of the applications encountered is large, we try to present every domain in a simple way and explain how random matrix models can bring new insights to those fields. The common element of the thesis being matrix models, each part has been written so that readers unfamiliar with the domains of application but familiar with matrix models should be able to understand it.

L'adoption récente et généralisée des systèmes d'automatisation des véhicules, avec l’incorporation de la connectivité entre voitures, a encouragé l’utilisation des techniques comme le Contrôle Croisière Adaptatif Coopératif (CACC) et la conduite en convoi. Ces techniques ont prouvé l’amélioration du flux de trafic et la sécurité de la conduite, tout en réduisant la consommation d’énergie et les émissions CO_2. Néanmoins, la robustesse et la stabilité stricte du convoi, malgré les délais de communication et l’hétérogénéité des convois, restent des sujets de recherche en cours. Cette thèse a pour sujet la conception, l’analyse et validation de systèmes de contrôle pour le car-following automatisé et coopératif, en ciblant l’augmentation de ses avantages et son usage, en se concentrant sur la robustesse et la stabilité du convoi même sur des séries de véhicules hétérogènes avec des retards de communication. Une structure feedforward/feedback est développée, dont sa modularité est fondamentale pour la mise au point des approches avec des objectifs différents mais complémentaires. L’architecture permet non seulement l’adoption d’une stratégie d’espacement pour la range entière de vitesse, mais elle peut aussi être employée dans le cadre d’un CACC basé sur une machine d’état pour la conduite en convoi sur des environnements urbains avec des capacités de freinage d’urgence et de rejoint du convoi. Des différents algorithmes pour la conception de systèmes de contrôle feedback pour la régulation des distances sont présentés, pour quoi le calcul d’ordre fractionnaire démontre fournir des réponses fréquentielles de boucle fermé plus précises et satisfaire des besoins plus exigeantes. La performance est assurée malgré l’hétérogénéité avec la proposition de deux approches feedforward différents. Le premier est basé sur une topologie en considérant que le véhicule précédent dans la boucle, tandis que le deuxième inclut le véhicule leader pour améliorer la performance de suivi. Les algorithmes proposés sont validés avec des études de stabilité dans le domaine du temps et fréquence, ainsi que simulations et expérimentations réelles. / Recent widespread adoption of vehicle automation and introduction of vehicle-to-vehicle connectivity has opened the doors for techniques as Cooperative Adaptive Cruise Control (CACC) and platooning, showing promising results in terms of traffic capacity and safety improvement, while reducing fuel consumption and CO_2 emissions. However, robustness and strict string stability, despite communication delays and string heterogeneity is still an on-going research field. This thesis deals with the design, study and validation of control systems for cooperative automated car-following, with the purpose of extending their benefits and encourage their employment, focusing on robustness and string stability, despite possible V2V communication delays and string heterogeneity. A feedforward/feedback hierarchical control structure is developed, which modularity is fundamental for the proposal of approaches that target different but complementary performance objectives. The architecture not only permits the adoption of a full speed range spacing policy that target multiple criteria, but can also be employed in a state machine-based CACC framework for urban environments with emergency braking and platoon re-joining capabilities in case of pedestrian interaction. Different feedback control design algorithms are presented for the gap-regulation, for which the fractional-order calculus is demonstrated to provide more accurate closed loop frequency responses and satisfy more demanding requirements. Desired performance is ensured in spite of string heterogeneity through the proposal of two feedforward methods : one based on predecessor-only topology, while the second includes the leader vehicle information on feedforward to gain tracking capabilities. Proposed control algorithms are validated through time and frequency-domain stability studies, simulation and real platforms experiments.

We introduce slow-roll inflation in string theory on both a conceptual level and a detailed one. In order to do this we first briefly review important concepts of inflation and string theory. We then reconstruct models of string inflation in the so-called Racetrack scenario for two different cases where the difference being the number of Kähler moduli used as inflaton. Furthermore, we briefly relate our results to the more recent discussion on whether AdS/dS solutions actually exist in string theory. In this instance our results seem to indicate that uplifting is a crucial component to obtain AdS/dS solutions.

String trimmers or weed cutter or strimmer is one of the inevitable tool for a professional gardener. They are helping gardeners for maintaining the lawn and farmland. These machines have been used by human for a quite long time. Professionals normally uses the bike handle type string trimmer and the amateurs who has small gardens normally uses loop handle one. The bike handle models are more powerful and gives more comfort for long time working. While performing the trimming process users are using the handles to steer and control the machine. Handle is the main touch point of the machine and it needs to provide enough comfort and assist the functions.Cramer, a German garden tools brand owned by The Globe Group, is focusing on researching and developing Garden power tools for amateurs as well as professional users. For them it is important to satisfy the customer and improve the user experience of their products.This project is focused only on the handle of the string trimmer to improve the overall user experience. This project mainly deals with the ergonomic aspects of the handle for a larger percentile of population. It is very important to make a handle were the professional users are going to use longer period of time. Along with the comfort this project put stress on increase the user experience by giving modern, friendly and premium expression visually as well as physically. Even though the project is to develop a handle concept, it needs to go along with the overall brand language.