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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
121

Acoustics and fractal dimension of snapping shrimp's community in subtidal zone.

Ho, Chin-cheng 09 January 2007 (has links)
Snapping shrimp is the well-known source of biological sound in subtidal zone. Sounds were created by imploding a cavitation bubble which is generated under the tensile forces of the claw after a high-velocity water jet has been formed. The sounds of snapping shrimp is not only for attacking and defending, but also for communicating with each others. These sounds thus become the material of studying complex behavior arisen from interaction between individuals. This paper studies the change of fractal dimension of snapping shrimp¡¦s noises in different condition of environment. Sounds of snapping shrimp in Chigu lagoon and Tanshui estuary were recorded respectively. With the help of computer software to edit and calculate, the fractal dimension was taken as indicator for the complexity of communication. The behavior was assumed to be affected by many factors at the same time. Analysis of multiple regression with fractal dimension as dependent variables show that the fractal dimensions increased with night time, water temperature, and the ebb tide, but decrease with light intensity. Diurnal hour is the most significant factor in Chigu area. Analysis of Tanshui¡¦s data showed fractal dimension decrease with water depth.
122

Coherent Reflection of Acoustic Plane Wave From a Random Sea floor

Shen, Chien-Ou 09 August 2001 (has links)
The problem of coherent reflecton of an acoustic plane wave from a random seabed consisting of a randomly inhomogeneous sediment layer overlying a uniform elastic sea floor is considered in this analysis. The random perturbation in the sediment layer is attributable to the sound-speed variations, resulting in volume scattering due to medium inhomogenieties. An approach based upon perturbation theory, combining with a derived Green's function for a slab bounded above and below respectively by a fluid and an elastic half space ,is employed to obtain an analytic solution for the coherent field in the sediment layer. A linear system is then constructed to facilitate the analysis of the coherent reflection field. The results of the coherent reflection coefficient for various sediment randomness, frequency , sediment thickness, and sea floor elasticity have been numerically generated and analyzed. It was found that the higher/larger size of randomness , frequency, thickness, and shear-wave speed, the lower the coherent reflection. Physical interpretation for the characteristics of various results were provided.
123

A theoretical and experimental study on multiple scattering from bubbles, with emphasis on scattering from a bubble located close to the air-sea interface /

Kapodistrias, Georgios. January 2001 (has links)
Thesis (Ph. D.)--University of Washington, 2001. / Vita. Includes bibliographical references (leaves 75-80).
124

Tail separation and density effects on the underwater trajectory of the JDAM

Bushnell, Jillene Marie. January 2009 (has links) (PDF)
Thesis (M.S. in Meteorology and Physical Oceanography)--Naval Postgraduate School, December 2009. / Thesis Advisor(s): Chu, Peter. Second Reader: Almquist, Brian "December 2009." Description based on title screen as viewed on February 02, 2010. Author(s) subject terms: Hydrodynamic, STRIKE35, Joint Direct Attack Munition (JDAM), Mine Countermeasure (MCM), mine, improvised explosive device (IED), numerical modeling, Stand-off Assault Breaching Weapon Fuze Improvement (SOABWFI). Includes bibliographical references (p. 69-71). Also available in print.
125

Underwater acoustic backscatter from a model of Arctic ice open leads and pressure ridges

Browne, Michael Joseph. January 1987 (has links) (PDF)
Thesis (M.S. in Engineering Acoustics)--Naval Postgraduate School, June 1987. / Thesis Advisor(s): Medwin, Herman. Second Reader: Bourke, Robert H. "June 1987." Description based on title screen as viewed on March 16, 2010. DTIC Identifier(s): Mode conversion. Author(s) subject terms: Underwater Acoustics, Arctic Ice, Backscatter, Mode Conversion, Diffraction. Includes bibliographical references (p. 156-157). Also available in print.
126

Construction and testing of low noise Hydrophones /

Bakas, Konstantinos. January 2004 (has links) (PDF)
Thesis (M.S. in Applied Physics)--Naval Postgraduate School, June 2004. / Thesis advisor(s): Thomas J. Hofler, Bruce Denardo. Includes bibliographical references (p. 57). Also available online.
127

Acoustics in architectural design (an annotated bibliography on architectural acoustics)

Doelle, Leslie L. January 1965 (has links)
Thesis (M. ARCH.)--McGill University, 1965.
128

Performance bounds on matched-field methods for source localization and estimation of ocean environmental parameters /

Xu, Wen. January 1900 (has links)
Thesis (Ph. D.)--Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2001. / "Funding was provided by the Office of Naval Research under grant N00014-01-1-0257 and the WHOI Education Office." "June, 2001." Includes bibliographical references (p. 207-215).
129

Acoustic surveys of the sea floor near Hong Kong /

Chan, Yin-lui, Yinia. January 1966 (has links)
Thesis (Ph. D.)--University of Hong Kong, 1967. / 8 fold. charts in pocket. Mimeographed.
130

"Follow the leader" tracking by autonomous underwater vehicles (AUVs) using acoustic communications and ranging /

Kucik, Daniel P. January 2003 (has links) (PDF)
Thesis (M.S. in Applied Science (Robotics))--Naval Postgraduate School, September 2003. / Thesis advisor(s): Don Brutzman, Anthony Healey, Douglas P. Horner. Includes bibliographical references (p. 177-181). Also available online.

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