scholarly journals Subject-Specific Computational Modeling of Evoked Rabbit Phonation

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
Siyuan Chang ◽  
Carolyn K. Novaleski ◽  
Tsuyoshi Kojima ◽  
Masanobu Mizuta ◽  
Haoxiang Luo ◽  
...  
Keyword(s):  
Vocal Fold ◽  
Computational Models ◽  
Three Dimensional ◽  
Model Parameters ◽  
Individual Subject ◽  
Vocal Fold Vibration ◽  
Subject Specific ◽  
Vocal Fold Dynamics ◽  
1D Model

When developing high-fidelity computational model of vocal fold vibration for voice production of individuals, one would run into typical issues of unknown model parameters and model validation of individual-specific characteristics of phonation. In the current study, the evoked rabbit phonation is adopted to explore some of these issues. In particular, the mechanical properties of the rabbit's vocal fold tissue are unknown for individual subjects. In the model, we couple a 3D vocal fold model that is based on the magnetic resonance (MR) scan of the rabbit larynx and a simple one-dimensional (1D) model for the glottal airflow to perform fast simulations of the vocal fold dynamics. This hybrid three-dimensional (3D)/1D model is then used along with the experimental measurement of each individual subject for determination of the vocal fold properties. The vibration frequency and deformation amplitude from the final model are matched reasonably well for individual subjects. The modeling and validation approaches adopted here could be useful for future development of subject-specific computational models of vocal fold vibration.

Empirical Eigenfunctions and Medial Surface Dynamics of a Human Vocal Fold

2005 ◽  
Vol 44 (03) ◽  
pp. 384-391 ◽  
Author(s):  
N. Tayama ◽  
D. A. Berry ◽  
M. Döllinger
Keyword(s):  
Vocal Fold ◽  
High Speed ◽  
Computational Models ◽  
Imaging System ◽  
Vocal Folds ◽  
Sustained Oscillation ◽  
Medial Surface ◽  
Physical Mechanisms ◽  
Vocal Fold Vibration ◽  
Modes Of Vibration

Summary Objectives: The purpose of this investigation was to use an excised human larynx to substantiate physical mechanisms of sustained vocal fold oscillation over a variety of phonatory conditions. During sustained, flow-induced oscillation, dynamical data was collected from the medial surface of the vocal fold. The method of Empirical Eigenfunctions was used to analyze the data and to probe physical mechanisms of sustained oscillation. Methods: Thirty microsutures were mounted on the medial margin of a human vocal fold. Across five distinct phonatory conditions, the vocal fold was set into oscillation and imaged with a high-speed digital imaging system. The position coordinates of the sutures were extracted from the images and converted into physical coordinates. Empirical Eigenfunctions were computed from the time-varying physical coordinates, and mechanisms of sustained oscillation were explored. Results: Using the method of Empirical Eigenfunctions, physical mechanisms of sustained vocal fold oscillation were substantiated. In particular, the essential dynamics of vocal fold vibration were captured by two dominant Empirical Eigenfunctions. The largest Eigenfunction primarily captured the alternating convergent/ divergent shape of the medial surface of the vocal fold, while the second largest Eigenfunction primarily captured the lateral vibrations of the vocal fold. Conclusions: The hemi-larynx setup yielded a view of the medial surface of the vocal folds, revealing the tissue vibrations which produced sound. Through the use of Empirical Eigenfunctions, the underlying modes of vibration were computed, disclosing physical mechanisms of sustained vocal fold oscillation. The investigation substantiated previous theoretical analyses and yielded significant data to help evaluate and refine computational models of vocal fold vibration.

A Study of Vocal Fold Vibration Using a Slightly Compressible Fluid Domain

2009 ◽  
Author(s):  
D. J. Daily ◽  
S. L. Thomson
Keyword(s):  
Boundary Conditions ◽  
Incompressible Fluid ◽  
Compressible Fluid ◽  
Vocal Fold ◽  
Computational Models ◽  
Fluid Model ◽  
Vocal Folds ◽  
Moving Wall ◽  
Slightly Compressible ◽  
Vocal Fold Vibration

During human voice production, air forced from the lungs through the larynx induces vibration of the vocal folds. Computational models of this coupled fluid-solid system have traditionally utilized an incompressible fluid domain. However, studies have shown that coupling of tracheal acoustics with vocal fold dynamics is significant. Further, in the absence of compressibility, some models fail to achieve self-sustained vibration. This presentation discusses a slightly compressible airflow model, fully coupled with a vocal fold tissue model, as a possible substitute for the traditional incompressible approach. The derivation and justification of the slightly compressible fluid model are discussed. Results are reported of a study of the nature of the coupling between the fluid and vocal fold regions for both slightly compressible and incompressible fluid domains using a commercial fluid-solid finite element package. Three different types of inlet boundary conditions, including constant pressure, constant velocity, and moving wall, are explored. The incompressible and slightly compressible models with the three boundary conditions are compared with each other and with experimental data obtained using synthetic self-oscillating vocal fold models. The results are used to validate the slightly compressible flow model as well as to explore candidate boundary conditions for vocal fold vibration simulations.

Parameter Estimation of Nonlinear Biomedical Systems Using Extended Kalman Filter Algorithm

2017 ◽  
pp. 76-99 ◽  
Author(s):  
Kamalanand Krishnamurthy
Keyword(s):  
Parameter Estimation ◽  
Kalman Filter ◽  
Extended Kalman Filter ◽  
Computational Models ◽  
Three Dimensional ◽  
Model Parameters ◽  
State Variables ◽  
Three Dimensional Model ◽  
Biomedical Systems ◽  
Estimation Of Model Parameters

Parameter estimation is a central issue in mathematical modelling of biomedical systems and for the development of patient specific models. The technique of estimating parameters helps in obtaining diagnostic information from computational models of biological systems. However, in most of the biomedical systems, the estimation of model parameters is a challenging task due to the nonlinearity of mathematical models. In this chapter, the method of estimation of nonlinear model parameters from measurements of state variables, using the extended Kalman filter, is extensively explained using an example of the three-dimensional model of the HIV/AIDS system.

scholarly journals Biomechanical modeling of the three-dimensional aspects of human vocal fold dynamics

2010 ◽  
Vol 127 (2) ◽  
pp. 1014-1031 ◽  
Author(s):  
Anxiong Yang ◽  
Jörg Lohscheller ◽  
David A. Berry ◽  
Stefan Becker ◽  
Ulrich Eysholdt ◽  
...  
Keyword(s):  
Vocal Fold ◽  
Three Dimensional ◽  
Biomechanical Modeling ◽  
Vocal Fold Dynamics

Design of a Mechanical Larynx With Agarose as a Soft Tissue Substitute for Vocal Fold Applications

2010 ◽  
Vol 132 (6) ◽  
Author(s):  
J. Q. Choo ◽  
D. P. C. Lau ◽  
C. K. Chui ◽  
T. Yang ◽  
C. B. Chng ◽  
...  
Keyword(s):  
Soft Tissue ◽  
Vocal Fold ◽  
Computational Models ◽  
Wound Closure ◽  
Lateral Expansion ◽  
Wound Closure Techniques ◽  
Vocal Fold Vibration ◽  
Flow Channels ◽  
Superior Surface ◽  
Biological Soft Tissue

Mechanical and computational models consisting of flow channels with convergent and oscillating constrictions have been applied to study the dynamics of human vocal fold vibration. To the best of our knowledge, no mechanical model has been studied using a material substitute with similar physical properties to the human vocal fold for surgical experimentation. In this study, we design and develop a mechanical larynx with agarose as a vocal fold substitute, and assess its suitability for surgical experimentation. Agarose is selected as a substitute for the vocal fold as it exhibits similar nonlinear hyperelastic characteristics to biological soft tissue. Through uniaxial compression and extension tests, we determined that agarose of 0.375% concentration most closely resembles the vocal fold mucosa and ligament of a 20-year old male for small tensile strain with an R2 value of 0.9634 and root mean square error of 344.05±39.84 Pa. Incisions of 10 mm lengthwise and 3 mm in depth were created parallel to the medial edge on the superior surface of agar phantom. These were subjected to vibrations of 80, 130, and 180 Hz, at constant amplitude of 0.9 mm over a period of 10 min each in the mechanical larynx model. Lateral expansion of the incision was observed to be most significant for the lower frequency of 80 Hz. This model serves as a basis for future assessments of wound closure techniques during microsurgery to the vocal fold.

scholarly journals Determination of subject-specific model parameters for visco-elastic elements

2006 ◽  
Vol 39 (10) ◽  
pp. 1883-1890 ◽  
Author(s):  
Cassie Wilson ◽  
Mark A. King ◽  
Maurice R. Yeadon
Keyword(s):  
Specific Model ◽  
Model Parameters ◽  
Subject Specific ◽  
Elastic Elements

scholarly journals The Mechanical Origin of the Radial Shape in Distichous Phyllotaxy Grass Plants

2021 ◽  
Author(s):  
Yoshiki Tokuyama ◽  
Yohei Koide ◽  
Kazumitsu Onishi ◽  
Kiwamu Hikichi ◽  
Miku Omachi ◽  
...  
Keyword(s):  
Time Course ◽  
Computational Models ◽  
Shape Change ◽  
Kinematic Model ◽  
Elevation Angle ◽  
Three Dimensional ◽  
Oryza Rufipogon ◽  
Model Parameters ◽  
Isogenic Line ◽  
Wild Rice Species

Abstract Three-dimensional plant shapes are influenced by their phyllotaxy, which plays a significant role in their environmental adaptation. Grasses with distichous phyllotaxy have linearly aligned culms and usually have vertical fan-like shapes. Counterintuitively, some distichous phyllotaxy grasses have radial shapes. Here, we investigate the organ-level mechanism underlying radial shape development in the distichous phyllotactic wild rice species (Oryza rufipogon). Detailed time-course phenotyping and three-dimensional micro-computed tomography showed that changes in the elevation angle in the main culm and azimuth angle in the primary tillers contribute to radial shape development. To infer the mechanical basis of the shape change, we simulated the movements of culms controlled by different kinematic factors. The computational models predicted that the combination of movements, including that controlled by negative gravitropism, produces the overall radial shape. This prediction was experimentally assessed. The analysis using a near-isogenic line of the gene, PROG1 for prostrate growth and the gravitropic mutant (lazy1) showed an association between genes and our model parameters. Our findings provide a simple, yet substantial, kinematic model for how the shape in distichous phyllotaxy plants changes as part of their adaptation to the surrounding environment.

scholarly journals Manufactured solutions and the numerical verification of isothermal, nonlinear, three-dimensional Stokes ice-sheet models

2012 ◽  
Vol 6 (4) ◽  
pp. 2689-2714 ◽  
Author(s):  
W. Leng ◽  
L. Ju ◽  
M. Gunzburger ◽  
S. Price
Keyword(s):  
Computational Models ◽  
Initial Conditions ◽  
Three Dimensional ◽  
Ice Sheet ◽  
Analytic Solutions ◽  
Model Parameters ◽  
Numerical Verification ◽  
Order Partial Differential Equation ◽  
Manufactured Solutions ◽  
Manufactured Solution

Abstract. The technique of manufactured solutions is used for verification of computational models in many fields. In this paper we construct manufactured solutions for models of three-dimensional, isothermal, nonlinear Stokes flow in glaciers and ice sheets. The solution construction procedure starts with kinematic boundary conditions and is mainly based on the solution of a first-order partial differential equation for the ice velocity that satisfies the incompressibility condition. The manufactured solutions depend on the geometry of the ice sheet and other model parameters. Initial conditions are taken from the periodic geometry of a standard problem of the ISMIP-HOM benchmark tests and altered through the manufactured solution procedure to generate an analytic solution for the time-dependent flow problem. We then use this manufactured solution to verify a parallel, high-order accurate, finite element Stokes ice-sheet model. Results from the computational model show excellent agreement with the manufactured analytic solutions.

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