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Home > News > Ph.D. Thesis > Ph.D. Thesis 2019

Friday 29th November 2019, thesis defense of Anne BOUVET - 09h00, K118 Amphitheater, LEGI, Bergès site

Experimental and theoretical contribution to the analysis and the modelling of the vocal folds vibration.

PhD thesis under the supervision of:

- Ecole Doctorale : EEATS
- Lieu de soutenance de la thèse: LEGI, K118
- Thèse préparée au sein des laboratoires Gipsa-lab et Legi

Abstract

The production of the human voice is generated by vocal folds auto-oscillation, due to the interaction between the air flow coming from the lungs and the elastic structure of the vocal folds. The purpose of this thesis is to realise an experimental and theoretical study in order to improve the understanding and modelling of this phenomenon and some of its perturbations.
Firstly, the MSePGG algorithm is proposed for the calibration of a non-invasive device for in vivo glottal area measurements. The algorithm is validated on mechanical replicas and illustrated for measurements on a human speaker.
Secondly, the vocal folds are covered by a thin layer of liquid, essential for phonation. An experimental approach is proposed to systematically study the influence of the presence of liquid on vocal fold replicas. Water spraying is shown to alter basic voice parameters as well as their perturbation. A simplified theoretical flow model accounting for the presence of both air and water is proposed and validated.
Thirdly, the effect of vertical vocal fold angular asymmetry, as occurring in the case of unilateral vocal fold paralysis, on the fluid-structure interaction is experimentally assessed. It is found that loss of full vocal folds contact leads to important variation on phonation features and their variations.
A simple theoretical model is shown to fit the increase of auto-oscillation onset threshold pressure with asymmetry angle. For future clinical applications obtained results suggest the further development of the MSePGG device and illustrate the multiple potential causes of voice perturbation.

Jury’s members:

  • Mme Anna Barney, Professeur des Universités, University of Southampton, Rapporteur
  • M. Jorge C. Lucero, Professeur des Universités, Department of Computer Science University of Brasília, Rapporteur
  • M. Yves Laprie, Directeur de Recherche, LORIA, Examinateur
  • M. Isao T. Tokuda, Professeur des Universités, Department of Mechanical Engineering, Ritsumeikan University, Examinateur