• Journal of the Korea Convergence Society
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• v.6 no.5
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• pp.9-14
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• 2015

In this paper, we analysis the electromagnetic scattering of an arbitrary shape dielectric cube subjected to plane wave incidence in three dimensions. MoM(Method of Moments)in which a surface of a body is divided with small triangular patches and equivalence principle are used to fuse the PMCHW(Poggio, Miller, Chang, Harrington, and Wu) Integral Equations with respect to equivalent currents on a dielectric body. Triangular patch and loop-patch basis functions that is robust in wide frequency ranges are used for MoM formulations. Proposed method is very useful to analysis the induced current of arbitrary dielectric bodies and numerical results for a dielectric cube are presented.

• Computational Structural Engineering
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• v.6 no.2
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• pp.103-114
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• 1993

An advanced time-domain finite element formulation is presented for the displacement and stress analysis of isotropic, linear viscoelastic problems of a hereditary-type constitutive law. The semidiscrete finite element method with linear time-stepping scheme and an elastic-viscoelastic correspondence principle are used in the theoretical development. An efficient treatment of hereditary integral is introduced to improve the numerical accuracy, to reduce the computation time, and to avoid the use of large memory storage. Two-dimensional numerical examples of plane strain and plane stress are solved under the assumption on the material property of being elastic in dilatation and like three-element Voigt model in distorsion, and compared with the analytical solutions and the past numerical results to show the versatility and efficiency of the proposed method.

• Journal of the Korean Institute of Telematics and Electronics
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• v.8 no.6
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• pp.17-24
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• 1971

All improved method of analysis is developed to determine the chsrateristics of a dielectric antenna of arbitrary shape. The analysis is based on scattering principles. The concept of polariaztion current and charge densities is incorporated into the Stratton-Chu formula and un integral equation is established for the electric field intensities in the dielectric. A new technique involving an equivalent spherical cell is developed to solve the integral equatioil numerically. The radiation characterstics of an omnidirectional dielectric antellna are determined based on the near field obtained by this volume cell technique.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1123-1125
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• 2005

본 논문에서는 3차원 공간에 종이와 같은 박막형 유전체가 있을 때 임의의 점에서의 전계$\vec{E}$를 구하기 위해 유전체의 분극벡터$\vec{P}$를 미지수로 하는 경계적분법(Boundary integral method)을 사용한다. 경계적분법의 사용으로 FEM 3차원 해석에 있어서의 요소분할의 난이성 및 계수 행렬의 대형화로 인한 컴퓨터 수행능력의 한계를 극복할 수 있다. 여기서 분극벡터$\vec{P}$를 구하기 위해 전하에서의 전계${ves{E}}_s$에 의한 유전체내의 분극벡터$\vec{P}$를 수식으로 정리하여 $[\vec{K}][\vec{P}]=[\vec{E}]$ 형태의 $\vec{P}$를 미지수로 하는 system matrix를 구성한다. 위의 system matrix 통해 구해진 분극벡터 $\vec{P}$를 이용하여 유전체 밖의 한 점에서의 전계세기 ${\vec{E}}_m$를 구한 후 우리가 구하고자 하는 전계$\vec{E}$를 계산한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.219-222
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• 2007

The paper deals with the rigorous analysis of three layered media structures. The dyadic Green's function for three layer medium is derived. The Green's functions belonging to the kernel of the integral equation are expressed as Sommerfeld integrals, in which surface wave effects are automatically included. We propose this integral representation as the most appropriate in the spatial domain analysis of slive structure. Also, we used extraction method for the convergence of this integral function. Finally, some numerical results are presented. These computed value show good agreement with proposed this method.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.2 s.93
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• pp.222-227
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• 2005

The permittivity profile of PCB substrate in a wide bandwidth is obtained by applying the moment method to the reflection coefficients measured by an open-ended coaxial probe. In this paper, the relation between a reflection coefficients and the corresponding permittivity is expressed into an integral form and the reflection coefficient of PCB substrates with different thickness are calculated using the dispersive FDTD method. The simulation results assure the validity of our conversion procedure within $2.015\%$ error.

• Journal of the Institute of Convergence Signal Processing
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• v.5 no.4
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• pp.317-324
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• 2004

Electromagnetically coupled coaxial dipole (ECCD) array antenna with and without short-ended termination is investigated theoretically. The integral equations are derived for the structure by use of the Fourier transform and mode expansion of radial waveguide. The integrals appearing in the integral equations are evaluated along the branch cut instead of real axis for a faster convergent integral. The effects of slots and dipoles, short-ended termination length, and dielectric coating on the radiation characteristics are presented. Radiation pattern of the structure is also investigated. The results of the present method are compared with those of the commercial EM simulator and good agreement is found.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.12
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• pp.1817-1825
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• 2021

Omnidirectional mobile robots can be mobile in any direction without changing the robot's direction, making them easy to apply in many applications and providing excellent maneuverability. Omnidirectional mobile robots have non-linear dynamic components such as friction, making them difficult to model accurately. In this paper, we linearize the mobile robot system using the mobile robot's inverse dynamics and integral sliding mode control method to remove these nonlinear components. And the position and velocity gains are optimized using a genetic algorithm to realize the optimal performance of the proposed system control method. As a result of the performance evaluation, the genetic algorithm's control method showed superior performance than the control method with an arbitrary gain. And the proposed inverse dynamic and integral sliding mode control method can be applied to other control methods. It can be beneficial for designing a linear control system.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.1 s.104
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• pp.52-59
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• 2006

To construct its complex permittivity from the reflection coefficient of a thin film such as PCB substrate measured by open-ended coaxial probe, an integral equation is formulated using modal analysis and equivalent source. The accuracy of the conversion model based on the integral equation is confirmed in both cases of converted complex permittivities calculated from numerically computed and actually measured reflection coefficients. And the maximum valid frequency of open-ended coaxial probe is limited by the size of its flange.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.10
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• pp.1096-1103
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• 2003

In this paper, we analyze the transient electromagnetic response from three-dimensional(3-D) dielectric bodies using a time-domain PMCHW(Poggio, Miller, Chang, Harrington, Wu) formulation. The solution method in this paper is based on the Galerkin's method that involves separate spatial and temporal testing procedures. Triangular patch basis functions are used for spatial expansion and testing functions for arbitrarily shaped 3-D dielectric structures. The time-domain unknown coefficients of the equivalent currents are approximated by a set of orthonormal basis functions that are derived from the Laguerre polynomials. These basis functions are also used as the temporal testing. Numerical results involving equivalent currents and far fields computed by the proposed method are presented.