• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.38-42
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• 2003

In this paper, a radar scattering model for forest canopies has been developed based on an empirical rough surface scattering model and the radiative transfer theory. Leaves in the forest canopy are modeled by rectangular resistive sheets, brunches and trunks are modeled by cylinder, which sizes and orientations are randomly distributed. The scattering model has been verified with the measurement data of JPL/AirSAR system.

• 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.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.1
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• pp.87-93
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• 2002

The previous RST postulates that the scattering field, within each modal partial wave, comprise of the resonance and the background components. The new RST is recently developed by the product expansion of the scattering functions in the field of acoustics. The new formulation suggests that the scattering coefficients consist of resonance, non-resonance, and their interactional portions. In the scattering problems of acoustic waves, the moduli and phase of the resonance coefficient are obtained correctly by the new RST. In our recent works the new RST was successfully applied to the scattering problem of electromagnetic waves for coated conducting cylinder and sphere. In this paper, the new RST is extended to the 2-dimensional scattering problem of electromagnetic waves for a homogeneous dielectric cylinder, and the numerical results are compared with the previous RST.

• Proceedings of the IEEK Conference
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• 2003.11a
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• pp.549-552
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• 2003

The electrical current generated by heart creates not only electric potential but also a magnetic field. We have observed electrophysiological phenomena of the heart by measuring tangential components of magnetocardiogram(MCG) using 61 channel superconducting quantum interference device(SQUD) system. In this paper, we developed a new analysis method, which is based on the theory of electromagnetic field. We show some differences of the current direction between the normal MCG and the abnormal(ischemic heart disease) MCG.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.5
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• pp.492-498
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• 2015

As the integration of circuit components increases steadily, various EMS(Electromagnetic Susceptibility) problems have emerged from integrated circuits and electrical systems. The electromagnetic susceptibility of VCOs(Voltage Controlled Oscillator) is especially critical in RF systems. Therefore, in this paper, through the phase noise theory that models electrical oscillators as linear time variant systems, the EMS characteristics of representative VCO -ring VCO and LC VCO- with 1.2 GHz of reference oscillating frequency are analyzed under the existence of the electromagnetic noise coupled in power supply. An simulation algorithm is developed to extract impulse response function based on the phase noise theory. When there is no supply noise, the magnitude of the jitter of two oscillators were similar to around 2.1 ps, but in presence of supply noise, the jitter was significantly lower in LC VCOs than ring VCOs.

• The Journal of Korean Institute for Practical Engineering Education
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• v.2 no.2
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• pp.55-60
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• 2010

We usually encounter Electro-magnetics phenomenons and only feel some part of that, but it is hard to feel it visually. Moreover understanding physically and quantitatively is not a easy work. These electrostatic field theory, magnetostatic field theory and interchange magnetic field theory combined with electromagnetic field are formulated experimentally and theoretically by James Clerk Maxwell in 1873. Electromagnetic field takes electro-magnetic phenomenons as a expansion of formula originated in Maxwell equations. Since this is based on expansion of formula, it is hard to understand for many students not only middle school and high school students learning it at the first time but also college students studying physics as a elementary class and even majors in electromagnetic field. The program is developed as a visual aid to cope with these problems, and even to deal with complex problem to estimate solution using numerical method.

• Transactions of The Korea Fluid Power Systems Society
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• v.8 no.1
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• pp.1-9
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• 2011

The main design factors which effect on operating speed of linear actuator for valve operation are mass of plunger, electromagnetic motive force, inductance, and return spring, and these factors are not independent but related with each other in view point of design and electromagnetic theory. It is impossible to increase the operating speed by only change the value of any one design factor. The change of any one value results in change of any value related it in various design factors. This paper presents a speed increasing method of linear actuator using a solenoid design method by some governing equations which are composed of electromagnetic theory and empirical knowledge and permanent magnets as assistant material, and proved the propriety by experiments.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.609-611
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• 2005

In this study electromagnetic wave fields under power lines arc derived by dipole antenna theory and electromagnetic fields under 3 phase power lines with horizontal and vertical configuration are formulated. The calculation results by those formulas were consistent with the results of reference. The formulas were applied to 345[kV] and 765[kV] transmission lines constructed in our country.

• Proceedings of the KIEE Conference
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• 2006.07c
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• pp.1595-1596
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• 2006

In this study electromagnetic fields under power lines were derived by dipole antenna theory and electric fields under high voltage power lines were discussed with dependence of power factor cos $\phi$. And also electromagnetic fields under 3 phase power lines with horizenal and vertical configurations were formulated.

• Proceedings of the Korea Society for Simulation Conference
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• 2003.11a
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• pp.181-184
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• 2003

Electromagnetic field simulator have been developed on Java 2 platform (J2SE) because provides robust solutions for applications as well as object oriented design. The simulator can be easily utilized with independent platform. Physical variables for the simulator can be controlled by the user. The numerical results are immediately displayed with graphical images in real time. Therefore, this simulator is intended to be used for education such as antenna engineering, microwave engineering, electromagnetic theory and so on.