• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.1069-1070
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• 2012

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.891-892
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• 2010

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.8
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• pp.697-703
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• 2017

A teflon ionization modeling has been conducted to predict the performance of a PPT(Pulsed Plasma Thruster). One dimensional unsteady circuit model and Teflon ablation model were implemented. The Saha equation was adapted to predict the ionization of Carbon and Fluorine gas. The lumped circuit model including a resistance and a inductance model of a plasma was adapted to predict the magnitude of a discharge current. Numerical simulation results had good agreements with pervious research. The degree of current change according to PPT operating voltage was examined.

• Proceedings of the Korea Society for Simulation Conference
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• 2001.10a
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• pp.215-219
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• 2001

The resonators made of piezoelectric crystals such as a quartz crystal are widely used. Their frequency-temperature characteristics are of primary importance for their applications to the frequency control devices. The characteristics estimation is useful for determining their design parameters. In the present paper, several types of resonators are numerically analyzed. The numerical solutions are made using 3-D Finite Element Modeling, and the results are compared with the theoretical values whenever they are available. To demonstrate the validity of the present numerical approach, the application is made to the analysis of the plates with some well-established cutting angles. For the resonator stable with temperature change, the cutting angle is important in which the temperature coefficient of the first order is chosen to be zero. The rotated Y-cut plates in thickness-shear mode are considered. The equivalent circuit representation is often used fur describing the characteristics at the electrical terminals which enables the circuit analysis including the effect of temperature change by using the circuit simulators. The equivalent circuit parameters are obtained by fitting the admittance-frequency curve from the finite element analysis.

• The Transactions of the Korean Institute of Power Electronics
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• v.3 no.4
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• pp.353-364
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• 1998

This paper presents a systematic approach to the modeling of power electronic circuits with systemlongrightarrowlevel simulation l languages. It is shown that a circuit model reduces to one of four basic types according to input/output conditions. The e elementary models for single series components and shunt components are derived which are integrated to develop a m model of given converter circuit. The constraints imposed on the model development-matching input/output conditions a and avoiding algebraic loop-are discussed in relation to the realization example of a buck converter circuit model. It is s shown that the constraints can always be fullfilled by introducing fictitious interface blocks, which is generalized to the c concept of model transformation.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.461-464
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• 2009

The conventional electro-mechanical circuit break and relay are widely used in large-sized DC power system. However, recently due to high reliability, remote controllability and small power dissipation of a RSPC (Remote Solid State Power Controller), high-friendly DC power systems have increasingly adopted the RSPC as an essential element. In this paper, we have conducted the modeling of a RSPC circuit and the simulation analysis for $I^2t$ curve, respectively.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.634-636
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• 2021

In this study, we studied the macro-modeling of an feedback field-effect transistor (FBFET) using SPICE simulation. The previously presented macro-model of the FBFET is consisting of two circuits. one is charge integration circuit, and the other is current generation circuit. The previous current generation circuit has problem that can't predict performance accurately of the circuits, due to implementing only I_DS-V_GS characteristics. To solve this problem, we presents a model that can implement not only I_DS-V_GS characteristics but alos I_DS-V_DS characteristics by adding the diode in the current generation circuit.

• Proceedings of the IEEK Conference
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• 2001.06b
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• pp.133-136
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• 2001

A new package design method to reduce resonance effect due to an IC package is represented. Frequency-variant circuit model of the power/ground plane was developed to accurately reflect the resonance. The circuit model is benchmarked with a full wave simulation, thereby verifying its accuracy. Then it was shown that the proposed technique can efficiently reduce the resonance due to the IC package.

• Journal of the Korean Society of Safety
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• v.30 no.3
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• pp.114-122
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• 2015

In a fire hazard analysis (FHA) for nuclear power plant, various electrical circuit analyses are performed in the parts of fire loading analysis, fire modeling analysis, separation criteria analysis, associated circuit analysis, and multiple spurious operation analysis. Thus, electrical circuit analyses are very important areas so that reliability of the analysis results should be assured. This study is to establish essential electrical elements for each analysis for verification of the reliability of the electrical circuit analyses in the fire hazard analysis for nuclear power plants. Applying the results derived by the study to domestic nuclear power plants, it is expected to determine the adequacy of the fire hazard analysis report and contribute to the reliability of the fire hazard analysis of those plants.

• Journal of electromagnetic engineering and science
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• v.11 no.2
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• pp.122-127
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• 2011

A general analysis of an aperture-coupled vertically mounted strip antenna is presented to examine its circuit characteristics. Based on the present analysis, an equivalent circuit model is developed, and an analytic or semi-analytic evaluation of the related circuit element values is described. The effects of structure parameters on the antenna characteristics were studied with the developed equivalent circuit, and the design curves were obtained. To check the validity of the proposed analysis and design theory, two C-band antennas (5.0 GHz and 4.5 GHz) were designed and fabricated. Their computed characteristics, derived from the proposed network analysis, were compared with the measurement and simulation results. The error of the current model in predicting the operating center frequency was less than 0.50 %. In addition, the observed bandwidth was found to be comparable to the conventional microstrip antennas. All the results fully validated the efficiency and accuracy of the proposed analysis and network model.