Thesis (M.S. in Computer Science)--Naval Postgraduate School, March 2005. / Thesis Advisor(s): Su Wen, Geoffrey Xie. Includes bibliographical references (p. 167-168). Also available online.

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Presented is an analysis of the performance of a matched field and matched beam processor in localization of a shallow water source using a 63-element bottom-moored planar array. Two scenarios are considered: in the first, a stationary, submerged CW source is localized in a high SNR environment; in the second, the source is being towed in the presence of multiple ship-generated directional noise sources. Array element localization is carried out using regularized linear inversion on transients from light bulb implosions around the array. The method provides the simplest array shape solution while still fitting the data and initial hydrophone position estimates to a statistically appropriate level. Estimation of geoacoustic parameters is accomplished using a hybrid inversion algorithm producing a robust geoacoustic model which is subsequently used to produce replica acoustic fields for the full field localization methods. Localization proved highly successful for the first scenario, while increased noise and geometrical limitations led to moderate performance in the second scenario.

The traditional study of underwater explosions (UNDEX) with respect to ship damage became of interest during World War II when torpedo explosions near a ship created more damage than a direct hit. Following the war, many full scale ship shock trials were conducted that provided much of the empirical data that is used in the field today. However, one type of shock phenomena became of interest in the late 1960s that potentially could be more damaging than a typical underwater explosion; an implosion. Crude implosion experiments were conducted in the late 1960s. Although these experiments collected data on pressure waves, more emphasis was placed on the acoustical properties associated with an implosion event. Today, one of the Navy's concerns is about the potential for the implosion of a pressure vessel in close proximity to a submarine hull. A computational approach is desired that will predict the source strength of an implosion. This thesis will cover the basic principals of underwater shock phenomena, including explosions and implosions. Drawing from previous experiments and computational simulations, a detailed investigation of the implosion event will be made using, DYSMAS, a coupled Eulerian-Lagrangian solver. DYSMAS will be used to compare the characteristics of implosion and explosion events. / US Navy (USN) author.

The control of a remotely operated vehicle (ROV) for moving stably at very low speed presents several difficulties due to the nonlinear dynamics of the vehicle. Therefore, precise motion control relies on a good understanding of the vehicle response in correspondence with the input thrust of thrusters. This study developed a measurement system capable of measuring the thrust performance of a thruster. The thrust measurement system utilizes the lever principle to magnify output force and consequently increase the thrust measurement resolution. A voltage meter and a current meter are coupled to a power supply to continuously measure the voltage and current input to the thruster. The thrust measurement error resulting for friction and poor stiffness of the lever is significant. The thrust measuremnt is also disturbed by the electromagnetic interference from the thruster. Therefore, the stiffness of the lever is improved and a static preload is applied on the lever to reduce the error in thrust measurement. In addition, proper system grounding and optical isolation are designed in the measurement system for reducing electromagnetic interference in thrust measurement. To control the thruster by the ROV general purpose controller developed by the Institute of Undersea Technology, National Sun Yat-sen University, this study developed a DC motor controller. The motor controller includes a L298n motor driver and uses an ultra low power MSP430 microprocessor to control the speed and direction of a thruster. The performance of three commercial thrusters were tested by the thrust measurment system with different motor drivers. The measurement results of the thruster performance are in agreement with the data obtained from the thruster data sheets, which verifies the measurement accuracy and reliability of the thrust measurement system.

Thesis (S.M.)--Joint Program in Oceanography/Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, and the Woods Hole Oceanographic Institution), 2002. / Includes bibliographical references (p. 151-154).

Thesis (M.S.)--Naval Postgraduate School, 2002. / Thesis advisor(s): Joseph A. Rice, Kevin B. Smith. Includes bibliographical references (p. 43-44). Also available online.

Thesis (M.S. in Applied Physics)--Naval Postgraduate School, June 2004. / Thesis advisor(s): Joseph A. Rice, Thomas J. Hofler. Includes bibliographical references (p. 41). Also available online.

Thesis (M.S. in Engineering Acoustics)--Naval Postgraduate School, March 2004. / Thesis advisor(s): Thomas R. Howarth, Dehua Huang. Includes bibliographical references (p. 67-69). Also available online.

Thesis (Ph. D.)--University of Texas at Austin, 2000. / Vita. Includes bibliographical references (leaves 181-187). Available also in a digital version from Dissertation Abstracts.