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2 WORKSHOPS at MAVEBA 2015

Some pictures from the event can be found here.

2 WORKSHOPS at MAVEBA 2015

We are organizing 2 workshops within MAVEBA 2015 in Florence (Italy). Each workshop will have a duration of 45 min and they will be on 3 September at 14:00-14:45 (Workshop 1) and 14:45-15:30 (Workshop 2). More info at: http://pevoc-maveba.dinfo.unifi.it/september-3-2015-maveba/

WORKSHOP 1: Studying the physics of voice production using mechanical replicas
Xavier Pelorson, GIPSA-Lab, Grenoble
Stefan Becker, Friedrich Alexander-Universität, Erlangen

Making measurements on the human voice organ in vivo is invasive and difficult. Reproducibility is usually hard to achieve with living or excised tissue. For studying fundamental phenomena of the physics of voice production, it is often more convenient to resort to mechanical replicas of the various parts of the voice organ. In comparison to computer simulations, the physicality of replicas can impart a more immediate and intuitive appreciation of the structural dimensions and the mechanical and/or acoustical aspects of voice production. In some cases, a highly simplified geometry for the vocal folds or the vocal tract is useful; it facilitates the specification of parameters, and the validation by measurement of numerical simulations of the corresponding geometries. In other cases, a more realistic 3-D geometry is needed to answer the research questions; such as for the study of the influence of particular pathologies or the cause of particular voice features. Modern 3-D printers have opened up the possibility to recreate complex shapes from MRI data, recently even in soft materials.

In this workshop, we illustrate some applications of mechanical replicas in voice research. Descriptions and demonstrations will be given of

  • Vocal fold models cast in soft silicon plastic with properties close to that of human tissue.
  • Flow field measurements of the glottal jet, and the influence of the ventricular folds.
  • Creating smooth vocal tract constrictions for fricatives and plosives, with accurately specified 3-D geometry.
  • Possibilities and limitations of current 3-D printing techniques.
  • Significant results that are obtainable only using replicas.

Aims:

Having attended this workshop session, the participants will:

  • Have seen and interacted with voice-relevant mechanical replicas in action.
  • Have a greater understanding of the pros and cons of using replicas in voice research.

Questions may be addressed to Francesc Alías Pujol, falias@salleurl.edu.

WORKSHOP 2: Modelling human voice production with large-scale physics-based simulations
Oriol Guasch, La Salle Barcelona
Johan Jansson, KTH Stockholm

A complete numerical simulation of the physics of voice production is still a task so formidable as to be out of practical reach for most applications, even when using massively parallel supercomputers. However, advances in computing techniques and in our understanding of the issues involved are pushing the envelope for what can be done. Traditionally, the solid and fluid/aeroacoustic domains have been treated with separate tools and different methods. In this workshop, we showcase the state of the art in finite element methods (FEM) for simulating the biomechanical, aerodyna- mical and acoustical phenomena that are relevant to voice production, and to what extent they can be simulated in fewer steps or even in a single unified computational domain. This involves numerous issues of defining boundaries, topologies and material properties, and the reconciling of computations at vastly different scales of resolution in time and space. The endeavour brings together scientists from several disciplines, including phonetics, biomechanics, aerodynamics, acoustics and numerics. Since the total computational task for a complete direct numerical simulation remains overwhelming, several approximations and shortcuts are of crucial practical importance, including reduction from 3-D to 2-D vocal tracts, novel treatment of contact and collision, and lower-order models where appropriate.

An overview will be given of a toolset and a workflow for defining biomechanical models in 3-D to the generation of oscillation, flow and acoustic waves to the radiated sound. The tools are open software that can be used by academics for free. The workflow begins with ArtiSynth for biomechanical modeling of the vocal tract airway and vocal fold posturing. The results are used as dynamic, 3-D boundary constraints for the subsequent aerodynamic and acoustic modelling in FEMUSS and/or FEniCS.

Aims:

Having attended this workshop session, the participants will:

  • Have an appreciation of current possibilities and challenges of numerical, physics-based simulation of human voice production,
  • Have tried some interactive demos of biomechanics simulations
  • Know how to proceed further in numerical voice simulation