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Hearing Protection for High-Noise Environments
Final rept. 1 Oct 2007-30 Sep 2009
MONOPOLE RESEARCH THOUSAND OAKS CA
Pagination or Media Count:
The objective of our effort was 1 to develop mathematical algorithms and high fidelity software tools which would allow identification and understanding of relevant bioacoustic and psychoacoustic mechanisms responsible for the transmission of acoustic energy through non-airborne pathways to the cochlea, and 2 to apply these tools to significantly reduce the cost of subsequent experiments. The integral-equation approach to solution of large elasto-acoustic problems, pursued in this project, offers valuable and unique advantages. The most important of these are 3 High accuracy characteristic of the integral-equation approach. 4 Applicability to problems involving high-density objects immersed in air, with an exact treatment of the infinite background medium, and with special methods for accurate description of wave penetration through the high-contrast air-tissue interface. 5 Applicability to large problems involving tens of millions of unknowns, and including fine, sub-millimeter scale, geometrical details. 6 An efficient numerical implementation involving non-lossy compression of the stiffness matrix and distributed-memory parallelization. 7 The developed code exhibits an approximately linear scaling of the computational cost with the number of unknowns, and almost perfect speedup with the number of processors. When completed, the developed code should significantly broaden the scope and improve accuracy of realistic biomedical and safety-related application, of particular importance being analysis of effects of noise on human subjects, and assessment and design of noise protection devices. Such simulations are, at present, limited because of prohibitive memory and computational requirements as well as insufficient accuracy of currently available approaches.
APPROVED FOR PUBLIC RELEASE