• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2001.11a
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• pp.7-11
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• 2001

본 논문에서는 방사 적분방정식의 해를 구하기 위하여 파수영역 웨이블릿 변환개념에 기반을 둔 윈도우 그린함수를 사용하여 파수영역에서 고속으로 산란필드를 계산하는 방법을 제안하였다. 그린함수에 적용된 파수영역 웨이블릿 변환은 공간영역에서 동일한 Q를 갖는 윈도우를 사용하여 필터링함으로써 등가적으로 구현하였다. 고유함수를 이용하여 관찰점을 중심으로 전개된 그린함수를 푸리에 변환한 후 파수영역에서 방사 적분을 계산함으로써 계산효율을 얻을 수 있음을 확인하였다. 관찰영역에서만 정확한 값을 갖는 고유함수로 전개된 그린함수는 그린함수에 윈도우 함수를 씌운 형태로 방사 적분방정식의 파수영역 표현에 적용하면 기존의 고속멀티폴법과 동일한 산란필드 공식을 얻을 수 있다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.1
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• pp.153-159
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• 2001

본 논문에서는 구형 공동의 포텐셜 그린 함수를 효율적으로 계산할 수 있는 기법을 제시하였다. 일반적으로 매우 느리게 수렴하는 구형 공동 그린함수에 Ewald 합 기법을 적용함으로써 매우 빠르게 수렴하는 두 급수의 합으로 그린함수를 변환하였다. 그 결과 매우 적은 수의 계산항만 사용한 경우에도 충분히 수렴하는 정확한 결과를 얻을 수 있다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.7
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• pp.1110-1114
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• 2001

The discrete wavelet concept in the k-domain is applied to efficiently represent Green function of integral equations. Application of discrete wavelet concept to Green function in the k-domain can be implemented equivalently by using spatial domain variable-sized windows. The proposed method consists of constant Q-filtering, changing the center of coordinates, and transforming spatially filtered Green functions into those in the k-domain. A mathematical expression of Green function based on the discrete wavelet concept is derived and its characteristics are discussed.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.5
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• pp.1001-1010
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• 2001

In TLM method, Discrete Green's function ABC have been used when improved the exactness of analyzing in wide frequency band. But this technology has a complicated process to apply absorbing boundary, which means it needs additional numerical analyzing process to obtain discrete Green's function data. so, In this paper, we propose new Green's absorbing layer for simple process to apply absorbing boundary. newly proposed Green's absorbing layer is produced by applying of loss operation, loading discrete Green's function with attenuation. A state of optimum absorbing would be obtained by relation between increasing rate of loss, attenuation constant and length of green's absorbing layer. and then Analysts of waveguide BPF is carried out using Green's absorbing layer within state of optimum absorbing, then this result is in corrective agreement with the result applying traditional discrete Green's function ABC.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.7
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• pp.1122-1130
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• 2001

In this paper, by applying the spectral domain wavelet concept to Green function, a fast spectral domain calculation of scattered fields is proposed to get the solution for the radiation integral. The spectral domain wavelet transform to represent Green function is implemented equivalently in space via the constant-Q windowing technique. The radiation integral can be calculated efficiently in the spectral domain using the windowed Green function expanded by its eigen functions around the observation region. Finally, the same formulation as that of the conventional fast multipole method (FMM) is obtained through the windowed Green function and the spectral domain calculation of the radiation integral.

• The Journal of the Korea Contents Association
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• v.7 no.2
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• pp.125-131
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• 2007

An iterative Green's function method (IGFM) is introduced in order to analyze complex electromagnetic waveguide stub structures in view of a university student. The IGFM utilizes a Green's function approach and an regional iteration scheme. A physical iteration mechanism with simple mathematical equations facilitates clear formulations of the IGFM. Scattering characteristics of a standard E-plane T-junction stub in a parallel-plate waveguide are theoretically investigated in terms of the IGFM. Numerical computations illustrate the characteristics of reflection and transmission powers versus frequency.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.5
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• pp.1530-1537
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• 1991

본 연구에서는 반무한 직선 계면균열의 상하면에 임의로 분포하는 어떠한 하 중에 대해서도 그 해석이 가능한 그린함수(Green's function)를 구하고자 한다. 이 를 위하여 반무한 직선 계면균열상의 임의의 한 점에 평면 집중하중이 작용하는 문제 와 비평면 집중전단하중이 작용하는 문제를 각각 택하였고, 이때 계면균열의 선단은 열려있다고 가정하였다. 이 문제를 풀므로써 균열선단부근의 응력성분을 결정하고 이로부터 그린함수의 의미를 지니는 응력강도계수에 대한 폐형해를 얻었다.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.6 s.324
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• pp.79-86
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• 2004

In the integration of Sommerfeld type for space domain Green's function, a accurate closed-from Green's function method provides more exact solution than the typical complex image method and two-level method. The accurate closed-form Green's function method is applied to obtain the space domain Green's functions of planar structures with general sources. Please put the abstract of paper here.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.37 no.11
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• pp.23-31
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• 2000

In the layered medium, infinite Sommerfeld integral must be evaluated to calculate a space domain Green's function. The complex image method and the two-level method provide rapid calculation and accurate solutions in the near-field region. However, in the intermediate and far-field region, the solutions are inaccurate due to the deformation of the sampling contour. In this paper, we propose a method to calculate an accurate closed-form Green's function for coplanar structure by sampling data on the real axis.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.4 s.95
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• pp.418-426
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• 2005

Based upon three level approximation and the steepest descent path(SDP) method, we consider an optimum choice of approximation path for derivation of new class of closed-flrm Green's functions which can lead to the analytic evaluation of MoM(Method of Moment) matrix elements. It is observed that the present method can give more accurate evaluation of the spatial Green's functions than the previous method, even without the advance investigation of the spectral functions, over a wide frequency range. In order to check the validity of the present method, some numerical results are presented.