The Optimization of Inverse problems for Two-Dimensional Conductors.
博士 === 淡江大學 === 電機工程學系博士班 === 94 === The thesis presents three related aspects of computational approach to the imaging of a conducting cylinder. In the first one, an imperfect conducting cylinder of unknown shape and variable conductivity is considered. Two different cases of inverse problem in fre...
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ndltd-TW-094TKU054420032016-06-01T04:14:21Z http://ndltd.ncl.edu.tw/handle/74844233305494366084 The Optimization of Inverse problems for Two-Dimensional Conductors. 二維導體逆散射問題之最佳化研究 Wei Chien 錢威 博士 淡江大學 電機工程學系博士班 94 The thesis presents three related aspects of computational approach to the imaging of a conducting cylinder. In the first one, an imperfect conducting cylinder of unknown shape and variable conductivity is considered. Two different cases of inverse problem in free space and half space have done respectively. In the second one, cubic-spline method and trigonometric series for shape description are used and compared in several different situations (half space, partially immersed, slab medium, and periodic conductor in free space). In the third one, the inverse scattering problem is addressed to discuss the CPU time for reconstructing a perfectly conducting cylinder for two different cases (half space and slab medium). It is solved by the improved Steady State Genetic Algorithm (SSGA) and Simple Genetic Algorithm (SGA) and the consuming time in finding out the global extreme solution of the objective function is compared. Based on the boundary conditions and the measured scattered field, a set of nonlinear integral equations is derived and the imaging problem is reformulated into an III optimization problem. In the first one, the genetic algorithm is employed to find out the global extreme solution of the objective function. Numerical results demonstrate that, even when the initial guess is far away from the exact one, a good reconstruction has been obtained. In the second one, the shape of the scatterer described by using cubic-spline method can be reconstructed. In such case, Fourier series expansion will fail. Numerical results show that the shape description by using cubic-spline method is much better than that Fourier series. In the third one, it is found that the searching ability of SSGA is much powerful than that of the SGA. The consuming time for converging to a global extreme solution by using SSGA is much less than that SGA. Numerical results show that the image reconstruction problem by using SSGA is much better than by SGA in time consuming. Chien-Ching Chiu 丘建青 2005 學位論文 ; thesis 145 zh-TW |
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博士 === 淡江大學 === 電機工程學系博士班 === 94 === The thesis presents three related aspects of computational approach to
the imaging of a conducting cylinder. In the first one, an imperfect
conducting cylinder of unknown shape and variable conductivity is
considered. Two different cases of inverse problem in free space and half
space have done respectively. In the second one, cubic-spline method and
trigonometric series for shape description are used and compared in several
different situations (half space, partially immersed, slab medium, and
periodic conductor in free space). In the third one, the inverse scattering
problem is addressed to discuss the CPU time for reconstructing a perfectly
conducting cylinder for two different cases (half space and slab medium). It
is solved by the improved Steady State Genetic Algorithm (SSGA) and
Simple Genetic Algorithm (SGA) and the consuming time in finding out the
global extreme solution of the objective function is compared. Based on the
boundary conditions and the measured scattered field, a set of nonlinear
integral equations is derived and the imaging problem is reformulated into an
III
optimization problem. In the first one, the genetic algorithm is employed to
find out the global extreme solution of the objective function. Numerical
results demonstrate that, even when the initial guess is far away from the
exact one, a good reconstruction has been obtained. In the second one, the
shape of the scatterer described by using cubic-spline method can be
reconstructed. In such case, Fourier series expansion will fail. Numerical
results show that the shape description by using cubic-spline method is much
better than that Fourier series. In the third one, it is found that the searching
ability of SSGA is much powerful than that of the SGA. The consuming time
for converging to a global extreme solution by using SSGA is much less than
that SGA. Numerical results show that the image reconstruction problem by
using SSGA is much better than by SGA in time consuming.
|
author2 |
Chien-Ching Chiu |
author_facet |
Chien-Ching Chiu Wei Chien 錢威 |
author |
Wei Chien 錢威 |
spellingShingle |
Wei Chien 錢威 The Optimization of Inverse problems for Two-Dimensional Conductors. |
author_sort |
Wei Chien |
title |
The Optimization of Inverse problems for Two-Dimensional Conductors. |
title_short |
The Optimization of Inverse problems for Two-Dimensional Conductors. |
title_full |
The Optimization of Inverse problems for Two-Dimensional Conductors. |
title_fullStr |
The Optimization of Inverse problems for Two-Dimensional Conductors. |
title_full_unstemmed |
The Optimization of Inverse problems for Two-Dimensional Conductors. |
title_sort |
optimization of inverse problems for two-dimensional conductors. |
publishDate |
2005 |
url |
http://ndltd.ncl.edu.tw/handle/74844233305494366084 |
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