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This work extends modelling of high prequency electric-acoustic transducers beyong current limiting approxilations, which is of interest to such applications as ultrasonic imaging, testing, tomography etc. / Thesis (PhD)--University of South Australia, 2001.

This work extends modelling of high frequency electric-acoustic transducers beyond current limiting approximations, which is of interest to such applications as ultrasonic imaging, testing, tomography etc. The developed methodology includes transient modelling of the acoustic potential field with dynamic Green?s functions and linear formulation of wave propagation in the moving reference frame. A finite difference model is determined to achieve fast numerical implementation. Developed is also experimental methodology for impulse response measurements, offering modifications of the inverse Wiener filter and introducing novel transducer equalisation increasing signal bandwidth. / thesis (PhD)--University of South Australia, 2001.

Thesis (Ph. D.)--University of Texas at Austin, 2008. / Vita. Includes bibliographical references.

Thesis (Ph. D.)--West Virginia University, 2008. / Title from document title page. Document formatted into pages; contains x, 97 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 84-88).

Thesis (Ph. D.)--University of California, San Diego, 1997. / Vita. Includes bibliographical references.

It is intended that this paper present an acceptable proof of the existence of a solution for the wave equation.

Observers are well known in the theory of dynamical systems. They are used to estimate the states of a system from some measurements. However, recently observers have also been developed to estimate some unknowns for systems governed by Partial differential equations. Our aim is to design an observer to solve inverse source problem for a one dimensional wave equation. Firstly, the problem is discretized in both space and time and then an adaptive observer based on partial field measurements (i.e measurements taken form the solution of the wave equation) is applied to estimate both the states and the source. We see the effectiveness of this observer in both noise-free and noisy cases. In each case, numerical simulations are provided to illustrate the effectiveness of this approach. Finally, we compare the performance of the observer approach with Tikhonov regularization approach.

No description available.

The elastic wave equation describes the propagation of elastic disturbances produced by seismic events in the Earth or vibrations in plates and beams. The acoustic wave equation governs the propagation of sound. The description of the wave fields resulting from an initial configuration or time dependent forces is a valuable tool when gaining insight into the effects of the layering of the Earth, the propagation of earthquakes or the behavior of underwater sound. In the most general case exact solutions to both the elastic wave equation and the acoustic wave equation are impossible to construct. Numerical methods that produce approximative solutions to the underlaying equations now become valuable tools. In this thesis we construct numerical solvers for the elastic and acoustic wave equations with focus on stability, high order of accuracy, boundary conditions and geometric flexibility. The numerical solvers are used to study wave boundary interactions and effects of curved geometries. We also compare the methods that we have constructed to other methods for the simulation of elastic and acoustic wave motion.