Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 30 for “"Acoustic Tomography"”.
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Basin-scale tidal measurements using acoustic tomography
Travel-times of acoustic signals were measured between a bottom-mounted source near Oahu and four bottom-mounted receivers located near Washington, Oregon, and California in 1988 and 1989. This paper discusses the observed tidal signals. At three out of four receivers, observed travel times at M2 …
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Acoustic tomography in the Straits of Florida
… of the Florida Current has been monitored via acoustic tomography. A reciprocal tomography experiment was conducted in the eastern half of the Florida Straits during mid October and November, 1983. A triangular array of transceivers, with leg separations of approximately 45 kilometers, was …
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Acoustic tomography in the straits of Florida
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1989.
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Acoustic Tomography and Thrust Estimation on Turbofan Engines
Acoustic sensing provides a possibility of measuring propulsion flow fields non-intrusively, and is of great interest because it may be applicable to cases that are difficult to measure with traditional methods. In this work, some of the successes and limitations of this technique are considered. …
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Estimation of sea surface wave spectra using acoustic tomography
… surface wave frequency-direction spectra using acoustic tomography. The analysis of acoustic (mode and ray) phase and travel time perturbations due to a rough sea surface is presented. Two canonical waveguides (ideal shallow water and linear squared index of refraction) are used as examples for …
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Estimation of sea surface wave spectra using acoustic tomography
Thesis (Sc. D.)--Joint Program in Oceanographic Engineering (Massachusetts Institute of Technology, Dept. of Ocean Engineering; and the Woods Hole Oceanographic Institution), 1987.
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Optimal ocean acoustic tomography and navigation with moving sources
Thesis (Sc. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1996.
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Applications of normal mode analysis to ocean acoustic tomography
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Physics, 1987
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High-frequency acoustic tomography in a high-current coastal environment
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 2000.
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Inverse methods and results from the 1981 Ocean Acoustic Tomography Experiment
Ocean acoustic tomography was proposed in 1978 by Munk and Wunsch as a possible technique for monitoring the evolution of temperature, density, and current fields over large regions. In 1981, the Ocean Tomography Group deployed four 224 Hz acoustic sources and five receivers in an array which fit …
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Cramér-Rao bounds for matched field tomography and ocean acoustic tomography
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1997.
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Inverse methods and results from the 1981 Ocean Acoustic Tomography Experiment
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth and Planetary Sciences, 1983.
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Fast acoustic tomography of costal, tidally-driven temperature and current fields
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1998.
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Estimation of planetary wave parameters from the data of the 1981 ocean acoustic tomography experiment
… fitted to the observations of the 1981 Ocean Acoustic Tomography Experiment. The experiment occupied a 300 km square area centered at 26°N, 70°W, and had a duration of ~80 days. The data set consisted of acoustic travel-time records, temperature records and CTD profiles, obtained from the …
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Measurements of a barotropic planetary vorticity mode in an eddy-resolving quasi-geostrophic model using acoustic tomography
… model to investigate whether the analysis of acoustic travel time changes can detect large-scale barotropic oscillations. Time series of sea surface elevation and upper and lower layer meridional currents are generated for comparison against a series of acoustic travel times. The spectra of …
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New Developments on Quantitative Imaging Using Ultrasonic Waves
… ultrasonic data. Two notable approaches are acoustic tomography and backscatter coefficient analysis. However, these techniques suffer from limitations that keep them from becoming widely used clinical tools. This dissertation presents several developments relevant to quantitative ultrasonic …
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Compressible Flow Characterization Using Non-Intrusive Acoustic Measurements
Non-intrusive acoustic instruments that measure fluid velocity and temperature have been restricted to low subsonic Mach number applications due to increased complexities associated with acoustic refraction, low signal-to-noise ratios, and a limited range of practical applications. In the current …
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Geographic Variations of Sound Channel Axis in the Global Ocean
… sound in various environments including ocean acoustic tomography and monitoring of global warming. In this work, sound speed and depth of the channel axis in the global ocean are characterized for their variation with the latitude, longitude, and depth.
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Inter-annual variability of acoustic ray travel times in the northeast Pacific
An acoustic tomography experiment consisting of a source near Hawaii and seven receivers along the west coast of North America was conducted from November 1987 to May 1988 and from February 1989 to July 1989. In this thesis, the acoustic ray travel times are analyzed in order to investigate …
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Study of basin scale acoustic transmissions
A basin-scale acoustic tomography experiment was conducted in the northeast Pacific from May 1987 to September 1987. In this thesis, the stability of the forward model is analyzed. There are large non-linearities in the changes in travel time between ray paths for the four seasons . I constructed a …
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