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Conducting Cylinder (conducting + cylinder)

Distribution by Scientific Domains

Engineering	40%

Selected Abstracts

Image reconstruction for a partially immersed imperfectly conducting cylinder by genetic algorithm

INTERNATIONAL JOURNAL OF IMAGING SYSTEMS AND TECHNOLOGY, Issue 4 2009
Wei Chien
Abstract This article presents a computational approach to the imaging of a partially immersed imperfectly conducting cylinder. An imperfectly conducting cylinder of unknown shape and conductivity scatters the incident transverse magnetic (TM) wave in free space while the scattered field is recorded outside. Based on the boundary condition and the measured scattered field, a set of nonlinear integral equations, and the inverse scattering problem are reformulated into an optimization problem. We use genetic algorithm (GA) to reconstruct the shape and the conductivity of a partially immersed imperfectly conducting cylinder. The genetic algorithm is then used to find out the global extreme solution of the cost function. Numerical results demonstrated that, even when the initial guess is far away from the exact one, good reconstruction can be obtained. In such a case, the gradient-based methods often get trapped in a local extreme. In addition, the effect of random noise on the reconstruction is investigated. © 2009 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 19, 299,305, 2009 [source]

Image reconstruction of a buried perfectly conducting cylinder illuminated by transverse electric waves

INTERNATIONAL JOURNAL OF IMAGING SYSTEMS AND TECHNOLOGY, Issue 6 2005
Yueh-Cheng Chen
Abstract This article presents a computational approach to the image reconstruction of a perfectly conducting cylinder illuminated by transverse electric waves. A perfectly conducting cylinder of unknown shape buried in one half-space and scatters the incident wave from another half-space where the scattered field is recorded. Based on the boundary condition and the measured scattered field, a set of nonlinear integral equations is derived, and the imaging problem is reformulated into an optimization problem. The steady state genetic algorithm is then employed to find out the global extreme solution of the cost function. Numerical results demonstrated that, even when the initial guess is far away from the exact one, good reconstruction can be obtained. In such a case, the gradient-based methods often get trapped in a local extreme. In addition, the effect of different noise on the reconstruction is investigated. © 2006 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 15, 261,265, 2005 [source]

Comparison of image reconstruction by using near-field and far-field data for an imperfect conductor

INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 2 2001
Chien-Ching Chiu
Abstract Image reconstruction by using near-field and far-field data for an imperfectly conducting cylinder is investigated. A conducting cylinder of unknown shape and conductivity scatters the incident wave in free space and the scattered near and far fields are measured. By using measured fields, the imaging problem is reformulated into an optimization problem and solved by the genetic algorithm. Numerical results show that the convergence speed and final reconstructed results by using near-field data are better than those obtained by using far-field data. This work provides both comparative and quantitative information. © 2001 John Wiley & Sons, Inc. Int J RF and Microwave CAE 11: 69,73, 2001. [source]

A uniform evaluation of the PO integral for 2D cylinders with arbitrary contour

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 5 2008
Felipe Vico Bondia
Abstract A new 2D fast physical optics method is presented for computing the field diffracted by a conducting cylinder with arbitrary contour. This method produces a fast solution with uniform accuracy in all frequencies and incidence/observation angles. The method is a combination of different techniques such as path deformation, Morse theory, and Fourier LS continuation. The technique presented here is also valid and uniformly accurate near the caustic singularities produced by surface points with infinite curvature radius. This method also takes into account the endpoint contributions. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1418,1423, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23364 [source]

On the estimation of scattering from convex conducting cylinders

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 3 2005
Vitaliy P. Chumachenko
Abstract A novel approach for estimating the high-frequency field scattered by a convex conducting cylinder is proposed. The theory is based on the locality property of short-wave scattering and considers the curvature of the target and the shadow-side currents. The approach is more accurate than the physical optics (PO) approximation and requires PO-comparable computational costs. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 45: 191,194, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20767 [source]

Microwave imaging of parallel perfectly conducting cylinders

INTERNATIONAL JOURNAL OF IMAGING SYSTEMS AND TECHNOLOGY, Issue 6 2000
Anyong Qing
This paper considers microwave imaging of parallel perfectly conducting cylinders using a solution of the scattering problem by the point-matching method. A cubic B-spline, real-coded genetic algorithm and an adaptive hybrid algorithm are proposed to solve the inverse problem. Previous shape functions in trigonometric series with arbitrary coefficients are nondefinite, which intensify the ill-posedness and slow the early time convergence of the algorithm. A novel shape function based on cubic B-splines is developed and the real-coded genetic algorithm is modified accordingly. Numerical simulation examples show that the early time convergence of the real-coded genetic algorithm is improved significantly. Next, the adaptive hybrid algorithm is developed to improve the late time convergence of the cubic B-spline real-coded genetic algorithm. © 2001 John Wiley & Sons, Inc. Int J Imaging Syst Technol 11, 365,371, 2000 [source]