Le XXème siècle marque le début de l'étude musicologique sur le chant basque, concept apparu dans le courant du XIXème siècle. La plupart des recherches insistent sur les spécificités de cette pratique. A cette même époque, l'enregistrement de ce répertoire permet la constitution d'archives sonores. Pourtant, musicologues et collecteurs de sources sonores ne se rencontrent pas. Or, l'examen approfondi des études musicologiques publiées sur le chant basque amène à penser que les caractéristiques musicales attribuées à cette pratique tout au long du XXème siècle ne sont pas toutes pertinentes, que ce soit dans les termes employés ou dans la conception même de la musique. Elles renseignent parfois plus sur les auteurs et le contexte d'écriture de l'ouvrage/ article que sur la musique elle-même. Ces descriptionspeuvent de ce fait être nuancées à la lumière de nouvelles analyses. Une comparaison diachronique et synchronique de sources écrites et musicales de la fin du XIXème siècle à la fin du XXème siècle permet d'une part d'observer le lien entre ce qui est " dit " sur le sujet du point de vue musicologique et ce que nous pouvons en entendre, et d'autre part de repérer les caractéristiques musicales communes qui se dégagent de l'ensemble. Nous formulons l'hypothèse qu'il existe dans le chant basque monodique, non des caractéristiques musicales intrinsèques, mais des éléments musicaux mobiles, variés, des " indices ", notamment du point de vue de la hauteur, qui peuvent être observés grâce à des outils d'analyse modernes.

In this thesis the characteristics of pitch and roll damping coefficients of missile models are investigated by using Computational Fluid Dynamics (CFD) techniques. Experimental data of NACA0012 airfoil, Basic Finner (BF) and Modified Basic Finner (MBF) models are used for validation and verification studies. Numerical computations are performed from subsonic to supersonic flow regimes. Grid refinement and turbulence model selection studies are conducted before starting the dynamic motion simulations. Numerical method of dynamic motion simulation is validated with a 2D NACA0012 airfoil. After the validation of numerical method, forced-oscillation motion is given to the BF and MBF models. In order to get deeper understandings about the characteristics of dynamic pitching and rolling motions, parametric studies are performed. The amplitude and frequency of forced-oscillation motions are investigated one by one. The effects of angle of attacks are also investigated for both pitching and rolling motions. The results of CFD simulations are compared with experimental data obtained from different wind tunnel and free flight tests. It is seen from these comparisons that experimental and numerical results are in good agreement throughout the whole flow regime. In conclusion, the numerical method presented in this study is validated and can be used for the prediction of pitch and roll damping coefficient of any missile configurations.

La técnica de las ondas de Lamb acopladas por aire representa un importante avance en el área de los Ensayos No Destructivos (END) de materiales laminares.Sin embargo la compleja naturaleza de las vibraciones mecánicas encontradas en acústica, hacen que el análisis y el estudio de esta área del conocimiento sea un tema muy complejo. De allí que la posibilidad de contar con una herramienta de simulación de software que permita la evaluación y prueba de diferentes configuraciones de excitación y recepción acústica utilizando la flexibilidad de un modelo de computadora sea de una gran utilidad y ayuda.El objetivo de la presente tesis es proveer al área de los END con un software de simulación gratuito: The LAMB Matlab® toolbox basado en el modelo del software libre de la GNU.El software es capaz de simular el comportamiento de sistemas de END basados en ondas de Lamb acopladas por aire en láminas isótropas simples utilizando transductores tipo array.El programa se basa en un arreglo tipo C-scan de un sistema de END y está compuesto por tres bloques principales: 1) Excitación, 2) Propagación y 3) Recepción.La verificación individual del funcionamiento de dichos módulos se presenta a lo largo de la tesis mediante una serie de comparaciones entre simulaciones y datos experimentales provenientes de diferentes pruebas. Por otro lado, la validación del programa completo se llevo a cabo por medio de experimentos en láminas de cobre y aluminio; utilizando un sistema real de END por ondas de Lamb acopladas en aire mediante arrays cóncavos.La influencia negativa en el desempeño general de dicho sistema de END real basado en este tipo de transductores se comprobó efectivamente mediante el simulador desarrollado. Esto se debió fundamentalmente al efecto de directividad de los sensores individuales en los transductores y a la simetría cóncava de los arrays.Para emular este comportamiento la tesis presenta un modelo geométrico bidimensional simple de un filtro espacial, junto a las simulaciones de un nuevo tipo de array plano propuesto.El programa desarrollado comprobó así mismo la naturaleza coherente de los campos acústicos emitidos en aire por las láminas sujetas a vibraciones de Lamb. Esto se realizó mediante la implementación de un conformador de haz simple de suma y demora; constituyéndose así la etapa inicial de procesamiento de señal del bloque de recepción del programa.El objetivo principal del presente trabajo fue contribuir con un modelo operativo de simulación y prueba de nuevos diseños de arrays e implementación de estrategias de procesado de señal útiles en sistemas de END basados en ondas de Lamb acopladas por aire.Finalmente, si bien el objetivo de la calibración del programa no se pudo conseguir; si se logró efectivamente un notable grado de similitud con un sistema de END real. / Air-coupled ultrasonic Lamb waves represent an important advance in Non- Destructive Testing and Evaluation (NDT & NDE) techniques of plate materials and structures. Examples of these advances are the characterization and quality assessment of laminate materials in manufacturing processes, the location of damaged parts in aircrafts and structure monitoring in the aerospace industry.However the rich and complex nature of mechanical vibrations encountered in acoustics make the subject of analysis and study of these systems a very complex task. Therefore a simulation tool that permits the evaluation and testing of different configuration scenarios using the flexibility of a computer model is an invaluable aid and advantage.The objective of this thesis is to provide the field of NDT with free open source software i.e. the LAMB Matlabrtoolbox. The toolbox is capable of simulating the behaviour of Lamb wave based NDE systems for single ideal isotropic laminates using air-coupled ultrasonic arrays. The programme usesa pitch-catch type of a Cscan NDE arrangement and is composed of three integrated sections each individually modelling a feature in the system: 1) Excitation, 2) Propagation, and 3) Reception.For assessment of the individual modules of the toolbox the thesis presents comparisons between each section simulations and the data obtained from different acoustic experiments. The validation of the complete simulator was carried out by evaluation tests on the copper and aluminium plates by use of a real hardware prototype of a Lamb wave based NDE system with aircoupled concave arrays.The negative impact on the performance of the real air-coupled NDE systembased on concave arrays was effectively confirmed by the programme. This was produced by the inherent directivity of the individual sensors as well as their concave arrangement. To emulate this behaviour the thesis introduces a simple two-dimensional geometric model for the inclusion of the spatial filtering effect of the sensors plus a group of simulations for a new proposed air-coupled plane array transducer.The software also verified the spatial coherent nature of the Lamb wave fields emitted by a plate in air. This was demonstrated by the implementation of a delay and sum beamformer to constitute an initial signal processing stage in the reception section.

Suction piles are used for anchoring the mooring lines at the seafloor. One of the challenges of their installing is the occurrence of the heave resonance of the pile-cable system and possibly the heave induced pitch resonance during the lowering process. When the heave and/or pitch frequency of the vessel which operates the lowering of the pile matches the heave natural frequency of the pile-cable system, the heave resonance may occur, resulting in large heave oscillations of the pile and thus significantly increasing loads on the lowering cable and lowering devices. Furthermore, the large heave may resonantly induce the pitch of a pile. To predict and possibly mitigate the heave/pitch resonance of the pile-cable system during the lowering process, it is crucial to under the mechanism of heave induced pitch resonance and estimate the added-mass and damping coefficients of the pile-cable system accurately. The model tests of the forced heave excitation of pile models were first conducted to investigate the added-mass coefficient for a pile model with different opening area ratios at its top cap at the Haynes Coastal Engineering Laboratory of Texas AandM University. In the model tests, it was observed that the resonant heave may occur if the heave excitation frequency matches the related heave natural frequency and the pitch resonance may be induced by the heave resonance. The results of the following theoretical analysis and numerical simulation of the heave excitation of the pile-cable system are found to be consistent with the related measurements, which is helpful to further understand the physics of lowering a pile-cable system. The results of this study may be used to determine the magnitudes of total heave added-mass and damping coefficient of a pile and the heave natural frequency of the pile-cable system based upon its main characteristics. The heave induced resonant pitch is found to occur when 1) the pitch natural frequency is roughly equal to one half of the heave natural frequency and 2) the heave excitation frequency is approximately equal to the heave natural frequency. If only one of the two conditions is satisfied, no significant pitch resonance will occur. These results may have important implications to the operation of lowering offshore equipment to the seafloor in deep water.

In this thesis / general feature selection methods and especially the use of periodicity and aperiodicity information in speaker verification task is searched. A software system is constructed to obtain periodicity and aperiodicity information from speech. Periodicity and aperiodicity information is obtained by using a 16 channel filterbank and analyzing channel outputs frame by frame according to the pitch of that frame. Pitch value of a frame is also found by using periodicity algorithms. Parzen window (kernel density estimation) is used to represent each person&rsquo / s selected phoneme. Constructed method is tested for different phonemes in order to find out its usability in different phonemes. Periodicity features are also used with MFCC features to find out their contribution to speaker identification problem.

The objective of this thesis is to design a system that can be used to retrieve the music songs by acoustic input. The system listens to the melody or the partial song singing by the Karaoke users, and then prompts them the whole song paragraphs. Note segmentation is completed by both the magnitude of the song and the k-Nearest Neighbor technique. In order to speed up our system, the pitch period estimation algorithm is rewritten by a theory in communications. Besides, a large popular music database is built to make this system more practical.

The work grafted hymnologies, a piece for chamber orchestra, explores connections between twentieth century formalist compositional techniques and formalist techniques of pretonal music. This document, which accompanies the score for the piece, provides an analysis of the work that explains the various techniques and their application to the music. This piece is composed in five large sections. The work pairs compositional techniques associated with pre-tonal music from those of twentieth century modernist music. For example, the second section employs the Medieval idea of tropes-- each time the melody is repeated, new melodic material is added, in the style of the elaborations to the Gregorian repertory that were common as early as the tenth century. This is paired with a single pitch class drone that evolves by timbral modulation, a technique influenced in part by Schoenberg and carried out exactingly by Elliot Carter. Each section contains a similar pairings, which are explained in detail herein. That these kinds of pairings could co-exist in a single piece seems natural; certainly, the intricate formalism that appeared in some Western concert music before 1600 exhibits a certain degree of aesthetic concurrence with the formalist music of the early to mid- twentieth century. Artistically, reaching back to the past (both near and far) and creating something new is an interesting exploration of how history can inform the creative process. / text

Neurological evidence indicates that instrumental musicians experience changes in the auditory system following skill acquisition and sensory training; yet, little is known about auditory neural plasticity in formally trained vocal musicians. Furthermore, auditory pitch discrimination and laryngeal control are recognized as essential skills for vocal musicians; however, the relationship between physiological variables, perceptual abilities, and vocal production is unclear. Electrophysiologic and psychoacoustic measures were used to examine pitch production accuracy as well as pre-attentive and active pitch discrimination between nonmusicians and two classes of musicians. Participants included 40 formally trained musicians (19 vocalists/21 instrumentalists) and 21 nonmusician controls. All were right-handed young adult females with normal hearing. Stimuli were harmonic tone complexes approximating the physical characteristics of piano tones and represented the mid-frequency range of the untrained female vocal register extending from C4 to G4 (F0 = 261.63-392 Hz). Vocal pitch recordings were spectrally analyzed to determine pitch production accuracy. Difference limens for frequency (DLFs) were obtained by an adaptive psychophysical paradigm. Pre-attentive auditory discrimination was assessed by auditory evoked potentials (AEPs), including the mismatch negativity (MMN). A standard tone (G4 = 392 Hz) and three deviants differing in frequency (1.5%, 3%, and 6% below) were presented in a multi-deviant paradigm. All musicians demonstrated superior pitch perception and vocal production compared to nonmusicians. Pitch perception and production accuracy did not significantly differ between vocalists and instrumentalists; however, pitch production accuracy was most consistent within the vocalist group. Music training appears to facilitate both auditory perception and vocal production regardless of music specialty. Pitch perception and production were correlated skills only for instrumental musicians. Vocalists demonstrated minimal variability for both skills so that perception and production were not correlated. These two skills may be independent abilities between which a relationship develops with training. AEP analysis revealed an influence of musical expertise on neural responses as early as 50 ms after onset of musically relevant stimuli. MMN responses indicate that vocal musicians as well as instrumental musicians have superior sensory memory representations for acoustic parameters of harmonic stimuli and imply that auditory neural sensitivity is developed by intense music training.

This thesis describes the analysis, fabrication and testing of a rotor with extremely flexible blades, focusing on application to a micro-helicopter. The flexibility of the rotor blades is such that they can be rolled into a compact volume and stowed inside the rotor hub. Stiffening and stabilization of the rotor is enabled by centrifugal forces acting on a tip mass. Centrifugal effects such as bifilar and propeller moments are investigated and the torsional equation of motion for a blade with low torsional stiffness is derived. Criteria for the design of the tip mass are also derived and it is chosen that the center of gravity of each blade section must be located ahead of the aerodynamic center. This thesis presents the design of 18-inch diameter two-bladed rotors having untwisted circular arc airfoil profile with constant chord. A systematic experimental investigation of the effect of various blade parameters on the stability of the rotor is conducted in hover and forward flight. These parameters include blade flexibility in bending and torsion, blade planform and mass distribution. Accordingly, several sets of blades varying these parameters are constructed and tested. It is observed that rotational speed and collective pitch angles have a significant effect on rotor stability. In addition, forward flight velocity is found to increase the blade stability. Next, the performance of flexible rotors is measured. In particular, they are compared to the performance of a rotor with rigid blades having an identical planform and airfoil section. It is found that the flexible blades are highly twisted during operation, resulting in a decreased efficiency compared to the rigid rotor blades. This induced twist is attributed to an unfavorable combination of tip body design and the propeller moment acting on it. Consequently, the blade design is modified and three different approaches to passively tailor the spanwise twist distribution for improved efficiency are investigated. In a first approach, extension-torsion composite material coupling is analyzed and it is shown that the centrifugal force acting on the tip mass is not large enough to balance the nose-down twist due to the propeller moment. The second concept makes use of the propeller moment acting on the tip mass located at an index angle to produce an untwisted blade in hover. It is constructed and tested. The result is an untwisted 18-inch diameter rotor whose maximum Figure of Merit is equal to 0.51 at a blade loading of 0.14. Moreover, this rotor is found to be stable for any collective pitch angle greater than 11 degrees. Finally, in a third approach, addition of a trailing-edge flap at the tip of the flexible rotor blade is investigated. This design is found to have a lower maximum Figure of Merit than that of an identical flexible rotor without a flap. However, addition of this control surface resulted in a stable rotor for any value of collective pitch angle. Future plans for increasing the efficiency of the flexible rotor blades and for developing an analytical model are described. / text

Η διαρκώς αυξανόμενη ζήτηση ηλεκτρικής ενέργειας, στους καιρούς μας, σε συνδυασμό με τη ραγδαία κλιματική αλλαγή, οδηγούν στην ανάγκη αναζήτησης οικονομικών, άφθονων και καθαρών πηγών για την παραγωγή της. Συνεπώς η αιολική ενέργεια κερδίζει έδαφος στις επιλογές των κρατών ανά τον κόσμο. Στην παρούσα διπλωματική θα αναλυθεί μια διάταξη ανεμογεννήτριας, η οποία αποτελείται από μια σύγχρονη μηχανή μόνιμου μαγνήτη (PMSG), έναν μετατροπέα συχνότητας (back-to-back converter) και ένα φίλτρο RL από την πλευρά του δικτύου. Με την επιλογή μας να χρησιμοποιήσουμε σύγχρονη μηχανή μόνιμου μαγνήτη κερδίζουμε σε αποδοτικότητα και αξιοπιστία. Σκοπός την εργασίας αυτής είναι αφενός η μελέτη και η ανάλυση του πλήρους συστήματος στο d-q στρεφόμενο σύστημα καθέτων αξόνων μέσω του μετασχηματισμού Park και αφετέρου η εφαρμογή του κατάλληλου σχεδιασμού ελέγχου, ώστε να επιτευχθεί η μέγιστη απομάστευευση ισχύος από τον άνεμο. Αυτό θα πραγματοποιηθεί λαμβάνοντας υπόψη τους περιορισμούς που θέτουν τα κατασκευαστικά χαρακτηριστικά της γεννήτριας και οι απαιτήσεις του δικτύου. Η προσομοίωση του συνολικού συστήματος θα γίνει στο περιβάλλον του Matlab/Simulink. Μέσω της προσομοίωσης αυτής θα προκύψουν οι αποκρίσεις των βασικών μεγεθών του συστήματος, από τα οποία θα εξαχθούν συμπεράσματα σχετικά με την ποιότητα των επιλογών μας. / The increasing demand for electricity, in our times, combined with the rapid climate change, leads to the need of economical, abundant and clean sources of production. Therefore, wind energy is gaining ground around the world. In this thesis a wind turbine topology will modeled and analyzed. It consists of a permanent magnet synchronous generator (PMSG), a frequency back-to-back converter and an RL filter from the network side. By using a permanent magnet synchronous generator the model becomes efficient and reliable. The initial purpose is studying an analyzing the complete system, using d-q rotating vertical shaft system with Park transformation. Implementation of the appropriate control design will follow, in order to achieve maximum wind power extraction. Constrains, which are posed by the generator contraction characteristics and network requirements, must and will be considered. The simulation of the complete system will take place in Matlab/Simulink computing environment. The responses of the fundamental units will be presented and valuated, in order to extract conclusions regarding the quality of different control methods.