Archive for the ‘researches 5’ Category
Wednesday, March 19th, 2008
Predicted attenuation of sound in a rigid-porous ground from an airborne source.
An approximate analytical formula has been derived for the prediction of sound fields in a semi-infinite rigid-porous ground due to an airborne source. The method starts by expressing the sound fields in an integral ...
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Wednesday, March 19th, 2008
Thermal boundary layer effects on the acoustical impedance of enclosures and consequences for acoustical sensing devices.
Expressions are derived for the acoustical impedance of a rectangular enclosure and of a finite annular cylindrical enclosure. The derivation is valid throughout the frequency range in which all dimensions ...
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Wednesday, March 19th, 2008
Efficient absorbing boundary conditions for Biot\'s equations in time-harmonic finite element applications.
Absorbing boundary conditions for two phase media previously presented by Zerfa and Loret [Earthquake Eng. Struct. Dyn. 33, 89-110 (2004)] have been improved by considering additionally absorbing waves with auxiliary angles of incidence. These ...
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Wednesday, March 19th, 2008
Demonstration of the invariance principle for active sonar.
Active sonar systems can provide good target detection potential but are limited in shallow water environments by the high level of reverberation produced by the interaction between the acoustic signal and the ocean bottom. The nature of the ...
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Wednesday, March 19th, 2008
Waveguide invariant focusing for broadband beamforming in an oceanic waveguide.
The performance of broadband sonar array processing can degrade significantly in shallow-water environments when interference becomes angularly spread due to multipath propagation. Particularly for towed line arrays near endfire, elevation angle spreading of multipath interference often ...
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Wednesday, March 19th, 2008
Controlled and in situ target strengths of the jumbo squid Dosidicus gigas and identification of potential acoustic scattering sources.
This study presents the first target strength measurements of Dosidicus gigas, a large squid that is a key predator, a significant prey, and the target of an ...
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Wednesday, March 19th, 2008
Joint time/frequency-domain inversion of reflection data for seabed geoacoustic profiles and uncertainties.
This paper develops a joint time/frequency-domain inversion for high-resolution single-bounce reflection data, with the potential to resolve fine-scale profiles of sediment velocity, density, and attenuation over small seafloor footprints ( approximately 100 m). The ...
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Wednesday, March 19th, 2008
Passive fathometer processing.
Ocean acoustic noise can be processed efficiently to extract Green\'s function information between two receivers. By using noise array-processing techniques, it has been demonstrated that a passive array can be used as a fathometer [Siderius, et al., J. Acoust. Soc. Am. 120, 1315-1323 ...
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Wednesday, March 19th, 2008
Range-dependent waveguide scattering model calibrated for bottom reverberation in a continental shelf environment.
An analytic model is developed for scattering from random inhomogeneities in range-dependent ocean waveguides using the Rayleigh-Born approximation to Green\'s theorem. The expected scattered intensity depends on statistical moments of fractional changes in ...
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Wednesday, March 19th, 2008
Bottom profiling by correlating beam-steered noise sequences.
It has already been established that by cross-correlating ambient noise time series received on the upward and downward steered beams of a drifting vertical array one can obtain a subbottom layer profile. Strictly, the time differential of the cross ...
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Wednesday, March 19th, 2008
Low frequency wind noise contributions in measurement microphones.
In a previous paper [R. Raspet, et al., J. Acoust. Soc. Am. 119, 834-843 (2006)], a method was introduced to predict upper and lower bounds for wind noise measured in spherical wind-screens from the measured incident velocity spectra. ...
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Wednesday, March 19th, 2008
Near field Rayleigh wave on soft porous layers.
Simulations performed for a typical semi-infinite reticulated plastic foam saturated by air show that, at distances less than three Rayleigh wavelengths from the area of mechanical excitation by a circular source, the normal frame velocity is close to ...
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Wednesday, March 19th, 2008
Attenuation and scattering of axisymmetrical modes in a fluid-filled round pipe with internally rough walls.
The attenuation of axisymmetric eigenmodes in a cylindrical, elastic, fluid-filled waveguide with a statistically rough elastic wall is studied. It is shown that small perturbation theory can be used to relate ...
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Wednesday, March 19th, 2008
Comparing turbulence models for flow through a rigid glottal model.
Flow through a rigid model of the human vocal tract featuring a divergent glottis was numerically modeled using the Reynolds-averaged Navier-Stokes approach. A number of different turbulence models, available in a widely used commercial computational fluid ...
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Wednesday, March 19th, 2008
Apparatus and method for identifying an organ from an input ultrasound image signal.
Kim NC.
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Wednesday, March 19th, 2008
System and method of representing personal profile in auditory form.
Lehman B.
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Wednesday, March 19th, 2008
Corrections for wavefront aberrations in ultrasound imaging.
Angelsen BA.
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Wednesday, March 19th, 2008
Sound producing crayon.
Tsang H.
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Wednesday, March 19th, 2008
Play data editing device and method of editing play data.
Tsukamoto K.
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Wednesday, March 19th, 2008
Audio fishing lure system for attracting species specific fish.
Williams JD.
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Wednesday, March 19th, 2008
Parametric ultrasound imaging using angular compounding.
Zagzebski JA.
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Wednesday, March 19th, 2008
Ultrasonic observation system.
Ueda M.
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Wednesday, March 19th, 2008
Ultrasonograph.
Umemura S, Kawabata K.
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Wednesday, March 19th, 2008
Support of a wavetable based sound synthesis in a multiprocessor environment.
Tico M.
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Wednesday, March 19th, 2008
Previous event feedback system for electronic player piano systems.
Sant MV.
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