1,321 research outputs found
Detailed Simulation of the Cochlea: Recent Progress Using Large Shared Memory Parallel Computers
We have developed and are refining a detailed three-dimensional computational model of the human cochlea. The model uses the immersed boundary method to calculate the fluid-structure interactions produced in response to incoming sound waves. An accurate cochlear geometry obtained from physical measurements is incorporated. The model includes a detailed and realistic description of the various elastic structures present. Initially, a macro-mechanical computational model was developed for execution on a CRAY T90 at the San Diego Supercomputing Center. This code was ported to the latest generation of shared memory high performance servers from Hewlett Packard. Using compiler generated threads and OpenMP directives, we have achieved a high degree of parallelism in the executable, which has made possible to run several large scale numerical simulation experiments to study the interesting features of the cochlear system. In this paper, we outline the methods, algorithms and software tools that were used to implement and fine tune the code, and discuss some of the simulation results
A Comprehensive Three-Dimensional Model of the Cochlea
The human cochlea is a remarkable device, able to discern extremely small
amplitude sound pressure waves, and discriminate between very close
frequencies. Simulation of the cochlea is computationally challenging due to
its complex geometry, intricate construction and small physical size. We have
developed, and are continuing to refine, a detailed three-dimensional
computational model based on an accurate cochlear geometry obtained from
physical measurements. In the model, the immersed boundary method is used to
calculate the fluid-structure interactions produced in response to incoming
sound waves. The model includes a detailed and realistic description of the
various elastic structures present.
In this paper, we describe the computational model and its performance on the
latest generation of shared memory servers from Hewlett Packard. Using compiler
generated threads and OpenMP directives, we have achieved a high degree of
parallelism in the executable, which has made possible several large scale
numerical simulation experiments that study the interesting features of the
cochlear system. We show several results from these simulations, reproducing
some of the basic known characteristics of cochlear mechanics.Comment: 22 pages, 5 figure
Simulation and Visualization of Medical Application to the Inner Ear of the Guinea Pig to Reduce Animal Experiments
We present a novel approach to simulate drug application to the inner ear of the guinea pig with the goal to reduce animal experiments and to increase the accuracy of measurements. The framework is based on a tetrahedral grid representing the individual compartments of the cochlea, associated with a finite element model used to simulate medical diffusion and clearance. In a first simulation scenario, we were able to compute transfer coefficients between the inner compartments of the ear, validating experiments from the literature, and to prove the existence of clearance at the inner scala tympani. In a second scenario, the cochlea was unwound to obtain a one-dimensional model for efficient simulation-based transfer coefficient identification. These coefficients are useful to predict the impact of novel medication application systems
Computational algorithms for the segmentation of the human ear
The main goal of this project is to identify an efficient segmentation algorithm for each anatomic structure of the ear. Therefore, in this paper, it is presented and analyzed computational algorithms that have been used to segment structures in images, especially of the human ear in Computed Tomography (CT) images
Minimal basilar membrane motion in low-frequency hearing
Low-frequency hearing is critically important for speech and music perception, but no mechanical measurements have previously been available from inner ears with intact low-frequency parts. These regions of the cochlea may function in ways different from the extensively studied high-frequency regions, where the sensory outer hair cells produce force that greatly increases the sound-evoked vibrations of the basilar membrane. We used laser interferometry in vitro and optical coherence tomography in vivo to study the low-frequency part of the guinea pig cochlea, and found that sound stimulation caused motion of a minimal portion of the basilar membrane. Outside the region of peak movement, an exponential decline in motion amplitude occurred across the basilar membrane. The moving region had different dependence on stimulus frequency than the vibrations measured near the mechanosensitive stereocilia. This behavior differs substantially from the behavior found in the extensively studied high-frequency regions of the cochlea
Computational processing and analysis of ear images
Tese de mestrado. Engenharia Biomédica. Faculdade de Engenharia. Universidade do Porto. 201
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