Today many types of communication are employed on seagoing vessels, such as radio, satellite and Wi-Fi but only one type of communication is practical for submerged vessels, the acoustic underwater modem. The "off-the-shelf" modems are sometimes difficult to update and replace, especially on a large submarine. But by separating the hardware from the signal processing and making the software modular more versatility can be achieved.   The questions that this thesis are asking are: is it possible to implement the signal processing in software? How small or large should the modules be? What kind of architecture should be used? This thesis shows that it is indeed possible to implement simple algorithms that can isolate a signal and read its content regardless of the hardware configuration. Calculations show that up to 13 kbps can be reached at a range of one kilometer. It is most practical to make the entire physical layer into one module and the size of the system could drastically change the type of architecture used.

This thesis is focused on possibility of constructing distributed underwater sonar which has an ability to increase or decrease number of sensor elements without any modification on its hardware. Each sonar module works individually. Its synchronization and communication between modules and the image processing unit are archived by using CAN protocol. This new design concept gives several advantages over conventional design.Only one prototype was made, but several modules must be combined in the actual application. The discussion about a complete system can be found in the future work section.The project composes of two main parts: design and building a prototype. The testing procedure and result of both parts are described and summarized with a conclusion.

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.

Thesis (M. Phil.)--University of Hong Kong, 2001. / Includes bibliographical references.

Thesis (Ph. D.)--University of Washington, 2001. / Vita. Includes bibliographical references (leaves 75-80).

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.

Thesis (M.S.)--Naval Postgraduate School, 2002. / Thesis advisor(s): Charles W. Therrien, Kevin B. Smith. Includes bibliographical references (p. 147-149). Also available online.

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.

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.

Thesis (M.S. in Operations Analysis)--Naval Postgraduate School, June 2004. / Thesis advisor(s): Arnold H. Buss. Includes bibliographical references (p. 123-124). Also available online.