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La conception d'un système ultrasonore passif couche mince pour l'évaluation de l'état vibratoire des cordes vocales / A speaker recognition system based on vocal cords’ vibrationsIshak, Dany 19 December 2017 (has links)
Dans ce travail, une approche de reconnaissance de l’orateur en utilisant un microphone de contact est développée et présentée. L'élément passif de contact est construit à partir d'un matériau piézoélectrique. La position du transducteur piézoélectrique sur le cou de l'individu peut affecter grandement la qualité du signal recueilli et par conséquent les informations qui en sont extraites. Ainsi, le milieu multicouche dans lequel les vibrations des cordes vocales se propagent avant d'être détectées par le transducteur est modélisé. Le meilleur emplacement sur le cou de l’individu pour attacher un élément transducteur particulier est déterminé en mettant en œuvre des techniques de simulation Monte Carlo et, par conséquent, les résultats de la simulation sont vérifiés en utilisant des expériences réelles. La reconnaissance est basée sur le signal généré par les vibrations des cordes vocales lorsqu'un individu parle et non sur le signal vocal à la sortie des lèvres qui est influencé par les résonances dans le conduit vocal. Par conséquent, en raison de la nature variable du signal recueilli, l'analyse a été effectuée en appliquant la technique de transformation de Fourier à court terme pour décomposer le signal en ses composantes de fréquence. Ces fréquences représentent les vibrations des cordes vocales (50-1000 Hz). Les caractéristiques en termes d'intervalle de fréquences sont extraites du spectrogramme résultant. Ensuite, un vecteur 1-D est formé à des fins d'identification. L'identification de l’orateur est effectuée en utilisant deux critères d'évaluation qui sont la mesure de la similarité de corrélation et l'analyse en composantes principales (ACP) en conjonction avec la distance euclidienne. Les résultats montrent qu'un pourcentage élevé de reconnaissance est atteint et que la performance est bien meilleure que de nombreuses techniques existantes dans la littérature. / In this work, a speaker recognition approach using a contact microphone is developed and presented. The contact passive element is constructed from a piezoelectric material. In this context, the position of the piezoelectric transducer on the individual’s neck may greatly affect the quality of the collected signal and consequently the information extracted from it. Thus, the multilayered medium in which the sound propagates before being detected by the transducer is modeled. The best location on the individual’ neck to place a particular transducer element is determined by implementing Monte Carlo simulation techniques and consequently, the simulation results are verified using real experiments. The recognition is based on the signal generated from the vocal cords’ vibrations when an individual is speaking and not on the vocal signal at the output of the lips that is influenced by the resonances in the vocal tract. Therefore, due to the varying nature of the collected signal, the analysis was performed by applying the Short Term Fourier Transform technique to decompose the signal into its frequency components. These frequencies represent the vocal folds’ vibrations (50-1000 Hz). The features in terms of frequencies’ interval are extracted from the resulting spectrogram. Then, a 1-D vector is formed for identification purposes. The identification of the speaker is performed using two evaluation criteria, namely, the correlation similarity measure and the Principal Component Analysis (PCA) in conjunction with the Euclidean distance. The results show that a high percentage of recognition is achieved and the performance is much better than many existing techniques in the literature.
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Epidemiologic Survey of a Unique Type of Task-Specific Dystonia in Brass MusiciansWallace, Eric (Trombonist) 12 1900 (has links)
Brass musicians are known to experience a performance problem that is sometimes called valsalva maneuver or musical stuttering. This problem is known to cause difficulty starting a first note, tension in the throat, and tightness in the chest. Unfortunately, the research literature lacks sufficient details for evidence-based interventions. Therefore, the purpose of this study is to characterize and define this performance problem as experienced by brass musicians. An online epidemiologic survey was developed and deployed to collect data from brass musicians who have experienced this problem in their own playing. The survey was designed to acquire data in order to characterize and define the phenomenon through a biopsychosocial framework. The survey was also designed to assess whether this problem aligns with Altenmuller's heuristic model of motor control disruptions. A diverse group of brass musicians (n = 252) participated and offered relevant details for characterizing and defining this problem. Analysis of characteristic data suggests this problem is not a form of musical stuttering. Considering these data through Altenmuller's model suggests that this problem is experienced as a spectrum of motor disruptions that can develop into a unique type of musician's dystonia. While additional research is warranted, the results of this study are applicable to brass musicians, brass pedagogues, music educators, and performing arts health clinicians.
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