• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.510-511
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• 2008

Fuel cell is a modular, high efficient and environmentally energy conversion device, it has become a promising option to replace the conventional fossil fuel based electric power plants. The high temperature fuel cell has conspicuous feature and high potential in being used as an energy converter of various fuel to electricity and heat. And, The research and development for the solid oxide fuel cell have been promoted rapidly and extensively in recent years, because of their high efficiency and future potential. Therefore this paper describes the manufacturing method and characteristics of anode electrode for solid oxide fuel cell, by the way, Ni-YSZ materials are used as anode of high temperature widely. So in this experiments, we investigated the optimum content of Ni, by the impedance characteristics, overvoltage. As a result, the performance of Ni-YSZ anode(40vol%) was better excellent than the others.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.8
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• pp.1251-1255
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• 2015

The purpose of this study is to measurement the cardiac output using hand to hand impedance method to provide convenience to user when measuring SV(stroke volume) with the use of ICG(Impedance Cardiography). We suggest the optimized modified formula, which can be applied when using impedance with the use of hand to hand Impedance. To verify this formula, a SV from transthoracic approach and hand to hand approach are compared for the 36 subjects, respectively. The acquired data was analyzed by using LabVIEW 8.6, analysis was implemented by SPSS 12.0. Fine difference was shown by individual. We showed that as a result of analyzing the ICG measurement value on thoracic and hand to hand, the correlation with SV was r=0.716, thereby having indicated the results of regression model in relatively high correlation.

• Proceedings of the KIEE Conference
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• 2007.10a
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• pp.469-470
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• 2007

In this paper, we propose a simple and relative electrode contact monitoring method. By exploiting the power line interference, which is regarded as one of the worst noise sources for bio-potential measurement, the relative difference in electrode impedance can be measured without a current or voltage source. Substantial benefits, including no extra circuit components, no degradation of the body potential driving circuit, and no electrical safety problem, can be achieved using this method. Furthermore, this method can be applied to multi-channel isolated bio-potential measurement systems and home health care devices under a steady measuring environment.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.6
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• pp.841-849
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• 2014

Urban railway with rectifiers is connected by parallel circuits because substations are joined by the power rail. Thus, if an input voltage of a substation is increased, then the voltage of rectifiers is also increased, and which leads to an increase in the peak power of the substation. To solve this problem, this paper proposes a new method reducing the peak power of substations by adjusting the operation number of rectifiers. Its feasibility is exemplified by some simulations performed for Incheon subway Line 1 and GA(Genetic Algorithm) method has been applied to obtain the optimal input. Simulation results show that peak power can significantly be reduced using the method proposed in this paper.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.63 no.4
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• pp.312-316
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• 2014

In this paper, a voltage sag is analyzed in case of superconducting fault current limiter (SFCL) installed in power distribution system where replaces the main power transformer to large one to meet the power demand. First, the power system is configurated to analyze the operation characteristics of the protective relay with replacement of the main transformer and application of the SFCL. Next, the method to meet the protection coordination is analyzed with large transformer using PSCAD/EMTDC. Finally, the bus voltage is investigated according to the impedance of both main transformer and SFCL in case that the SFCL is applied into feeder.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.5
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• pp.457-463
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• 2005

This paper presents a method for analyzing irregular shaped power distribution networks. The irregular shaped metal-dielectric-metal plane is split into several piece of rectangular segments to calculate the impedance of the irregular shaped plane. Impedance matrix for each rectangular segments is calculated using the Mobius transform method to reduce the calculation time. Then the segmentation and do-segmentation method is applied to the piece of rectangular segments. Applied to the 6 inch by 5 inch size irregular shaped board, the proposed method shows 10 times faster than the electromagnetic or circuit analysis method.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.317-320
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• 1999

In this study, the piezoelectric ceramics PZT powder was synthesized by Wet-Dry combination method. And the flexible 1-3-0 type composites were fabricated with piezoceramic PZT and Eccogel polymer matrix embedded 3rd phase. Dielectric constant of 1-3-0 type composites was lower than that of single phase PZT ceramics. Thickness mode coupling factor k/sub t/ which was comparable with single phase PZT ceramics and mechanical quality factor Qm were about 0.65 and 6, respectively. These composites are considered as a good candidates for broad-band type transducer applications. The acoustic impedance of 1-3-0 type composites was lower than that of single phase PZT ceramics. Therefore, these composites would be better used for hydrophone applications.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1584-1586
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• 2000

본 논문에서는 압전 변압기의 병렬 구동에 대해 연구하였다. 병렬 구동을 함으로서 단일 구동시에 대해 $\sqrt{2}$정도의 출력 전압을 얻었다. 적외선 온도계를 이용하여 압전 변압기의 온도 상승률을 측정한 결과 단일 구동시보다 병렬 구동에 진동 손실 에너지의 감소를 얻을 수 있어 온도 상승률을 억제할 수 있었다. 또한 병렬로 구동함으로서 압전 변압기의 출력 임피던스를 감소시키므로 단일 구동시보다 최대 효율을 나타내는 부하 저항이 감소하였고 100[$k\Omega$]에서 91[%]정도를 나타내었다.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.2819-2821
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• 2000

We introduce Adaptive Fuzzy Impedance Controller for force control when robot contact with environment. Because robot and environment was always effected by nonlinear conditions. it needs to deal with parameter's uncertainty. As. it induced Fuzzy system in impedance controller. it used fuzzy inference logic that has robustness about uncertainty to tune impedance controller stiffness gain. We applied adaptive fuzzy impedance controller in One-Link Robot system and the method shows a good performance on desired position and force control with intensional contacting environment.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.2216-2218
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• 2000

This paper deals with finite element eigenvalue problem using electric field intensity to extract the even and odd impedance for a coupled-line waveguide structure. Calculations for the even-and-odd impedance of a coupled line waveguide structure are achieved based on the relative impedance concept for a waveguide with electric and magnetic wall containes.