• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 1999.02a
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• pp.85-88
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• 1999

The study of HTS bulk in permanent magnet applications requires the calculation of forces acting on the bulk. Currents distribution in HTS Superconducting bulk is very important to determine this forces. We have made computer program to find this current distribution and this program is applied to some simple disc-shape HTS bulk being magnetised in a uniform field. The techniques for determination of currents are FEM analysis and iteration method.

• Journal of the Korean Institute of Telematics and Electronics
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• v.4 no.2
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• pp.29-34
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• 1967

On clarifing radiations from antenna, it is necessary to consider the contribution of the current distribution on te conductive supporter. The expression has not only analized the total radiative current distribution on the dipole antenna and its conductive supporter, in case when the former was placed closely and in parallel to the latter, but also shown the results of practical experiment.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.46-48
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• 1994

In this paper, for optimum design and good efficiency, the characteristics of a induction motor is analyzed by using electromagnetic field theory, Maxwell'equation with consideration of slot-teeth shape, materials, etc.

• Proceedings of the KIEE Conference
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• 1997.07a
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• pp.155-158
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• 1997

In design of current transformer, equivalent circuit parameters is obtained by electromagnetic analysis and used circuit simulation. Precise core secton area and turns of coil can be determined by circuit analysis. Therefore exact design of current transformer is possible by field and circuit analysis.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.30A no.11
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• pp.48-57
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• 1993

The ANSI recently adopted normalized site attenuation(NSA) as a validation procedure of open area test sites. In this paper, the theoretical NSA values specified in the truth vlues of NSA were calculated for an ideal test site when tuned dipoles are used. A method of moments technique is employed to evaluate these NSA values. The calculated NSA values are more accurate than that of the ANSI.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.29A no.7
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• pp.39-47
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• 1992

This paper showed that theoretical site attenuation curves were obtained simply by the method of moments analysis for current integral equations on antennas. Since the expansion coefficients of driving and receiving points were calculated from the method of moments procedure, site attenuations were evaluated simply using these basic antenna parameters. Theoretical site attenuations were calculated with half-wave resonant dipoles connected directly to a 50 ohm receiving system and connected to a 72/50 ohm matching network, respectively. Results were compared with other theoretical studies reported so far. Also included were experimental results for site attenuations to prove the validity of theoretical analysis.

• Journal of the Speleological Society of Korea
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• no.79
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• pp.41-46
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• 2007

지구자기장의 성인에 대하여 고찰하고 기존 학설에 대한 신 모델을 제안하였다. 지자기 성인의 가장 유력한 이론적 모델은 열전류와 열화학적 전류에 의한 자기장 형성이다. 하지만, 이 모델은 매우 한정적 조건을 바탕으로 설명하고 있으며, 동시에 지자기의 분산과 세기의 상쇄 요인을 내포하고 있기 때문에 설득력이 저하된다. 그러나 본 제안의 가설에서 주장하는 이온층 전류에 의한 지자기의 성인은 그와 같은 분산 요인이 있을 수 없으며, 그 결과로 나타나는 지자기의 새기와 방향도 일정하게 형성됨이 해석 가능하기 때문에 타당성과 설득력이 높은 완벽한 이론이다. 따라서 이온층 전류에 의한 보다 안정적인 지자기성인의 전자기학적 신 모델을 제안한다.

• Proceedings of the KIPE Conference
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• 2018.11a
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• pp.205-206
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• 2018

LLC 컨버터는 1차측 스위치의 ZVS, 2차측 다이오드의 ZCS를 만족하며 높은 Power density로 인해 여러 분야에서 각광 받고 있는 시기이다. 기존의 FHA를 통해 LLC 컨버터를 해석하여 전압이득을 구하고 이를 기반으로 설계를 하지만 실제로는 기본파 성분뿐만 아니라 고조파 성분을 포함하므로 다소 오차가 존재하게 된다. 따라서 이 논문에서는 기존의 FHA에서 반영하지 않았던 출력 캐패시터의 영향을 반영함으로써 보다 정확한 LLC 컨버터의 전압이득 곡선을 제안한다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.12 s.103
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• pp.1222-1228
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• 2005

Analysis on the field uniformity inside of a reverberation chamber was done at 2.45 GHz which is an operating frequency of MWO(Microwave Oven). The Schroeder's Quadratic Residue Diffuser was designed for the chamber, and 3 different types of diffusers have been investigated using the finite-difference time-domain(FDTD) method for the field characteristics of each type. Type 2 and 3 diffusers were filled with dielectric material, and the size of these could be designed smaller than Type 1, without degradation of field characteristic. Type 3 diffuser shows better results among the three types of diffusers in view of increased test region and better field uniformity.

• Geophysics and Geophysical Exploration
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• v.20 no.3
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• pp.121-128
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• 2017

Interpretation of time-domain electromagnetic (TEM) data has been made mostly based on one-dimensional (1-D) inversion scheme in Korea. A proper interpretation of TEM data should employ 3-D TEM forward and inverse modeling algorithms. This study developed a 3-D TEM modeling algorithm using a finite difference time-domain (FDTD) method with staggered grid. In numerically solving Maxwell equations, fictitious displacement current is included based on an explicit FDTD method using a central difference approximation scheme. The developed modeling algorithm simulated a small-coil source configuration to be verified against analytic solutions for homogeneous half-space models. Further, TEM responses for a 3-D anomaly are modeled and analyzed. We expect that it will contribute greatly to the precise interpretation of TEM data.