• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.91_92
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• 2009

As the increasing integrity of VLSI, the BIST(Built-In Self Test) is used as an effective method to test chips. Generally the pseudo-random test pattern generation is used for BIST. But it requires too many test patterns when there exist random resistant faults. Therefore we propose a mixed test scheme which applies to the circuit under test, a deterministic test sequence followed by a pseudo-random one. This scheme allows the maximum fault coverage detection to be achieved, furthermore the silicon area overhead of the mixed hardware generator can be reduced.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.5
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• pp.821-828
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• 2007

This paper proposes a new algorithm to find optimal location of open switches connecting feeders in distribuion system. In order to enhance power system reliability by minimizing outage area in case of fault, the load balance among the facilities such as transformers and feeders is considered to optimize. The combination of optimal position of normal open switches can be found by moving tie along the direct path connecting two feeders related to the open switch while the whole optimization problem is separated into many small problems. The proposed algorithm is shown by case study results that, it is simple and takes short calculation time to apply to the DAS (Distribution Automation System) in KEPCO (Korea Electric Power Cooperation).

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.53 no.1
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• pp.13-21
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• 2004

In the design of superconducting cable systems, quench analysis have to be advanced for applying to a real systems. It is necessary to calculate the current, voltage and resistance during the quench. Simulation program named EMTDC was used to analyze the quench state. Normal zone evaluation and quench development with EMTDC are one of the major features of quench analysis. This paper presents the two kinds of quench control models which are the Switch Control Type and the Fortran Control Type. In case of the quench developing area, the simplicity cable model consist of resistance, inductance and capacitance. The impedance of the pipe type superconducting cable is calculated by numerical analysis method. The resistance and inductance increased during quench. However the variation have an effect on the fault current. The voltage was also developed by resistance and inductance. This paper presents the relationship between the current. voltage, resistance and inductance during quench.

• Electrical & Electronic Materials
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• v.9 no.3
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• pp.310-319
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• 1996

본 연구에서는 초전도의 전반적인 시장규모, 에너지 분야에서의 고온 초전도 연구 진척 내용, 마지막으로 저온 초전도체의 기술현황을 토대로 저온을 고온 초전도체로 대체 시 이에 따른 대체 효과를 비교 분석하고자 하였다. 하지만 고온 초전도체에 관한 기술적 문제가 아직 많은 문제로 제기되고 있어 정확한 기술적 판단에는 아직 상당히 미흡하다고 여겨진다. 또한 초전도를 이용한 에너지 응용범위가 너무 광범위하여 본고에서는 대표적 응용분야 몇 가지만 소개하고자 한다. 참고로 4K와 77K의 차이점을 평가할 때의 기준은 자기장과는 무관하게 임계전류밀도를 77K에서 $10-^5$$cm^2$으로 가정 실시한 것이다.

• Proceedings of the KIEE Conference
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• 2006.10c
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• pp.297-299
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• 2006

Searching the region of interest on the Hough transform domain is done to determine the real road boundary on the high speed way. The mathematical morphology is employed to obtain the gradient image which is utilized in Hough transform. Many possible candidates of lines could appear on the ordinary road environment and simple selection of the strongest line segments likely to be fault boundary lines. To solve such problem, the search area for the candidates of the road boundary which is called the region of interest is limited on the Hough space. The effectiveness of the proposed algorithm has been shown with experimental results.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.10
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• pp.73-80
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• 1995

In this paper, a synthesis tool using matrix operations for designing multi-level Reed Muller circuits is described which has been named as MRM (Multi-level Reed Muller Minimizer). The synthesis method which uses matrix operations has advantages in effectively minimizing chip area, delay optimization and fault detection capability. However, it uses only truth-table type maps for inputs, synthesizing only small circuits. To overcome the weakness, our method accepts two-level description of a logic function. Since the number of cubes in the two-level description is small, the input matrix becomes small and large circuits can be synthesized. To convert two-level representations into multi-level ones, different input patterns are extracted to make a map which can be fed to the matrix operation procedure. Experimental results show better performance than previous methods. The matrix operation method presented in this paper is new to the society of Reed Muller circuits synthesis and provides solid mathematical foundations.

• Progress in Superconductivity and Cryogenics
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• v.19 no.2
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• pp.1-8
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• 2017

Recently, Research and development activity of HTS (High Temperature Superconducting) power application is very progressive worldwide. Especially, HTS cable system and HTSFCL (HTS Fault current limiter) system are proceeding to practical stages. In such system and equipment, cryogenic cooling system, which makes HTS equipment cooled lower than critical temperature, is one of crucial components. In this article, cryogenic cooling system for HTS application, mainly cable, is reviewed. Cryogenic cooling system can be categorized into conduction cooling system and immersion cooling system. In practical HTS power application area, immersion cooling system with sub-cooled liquid nitrogen is preferred. The immersion cooling system is besides grouped into open cycle system and closed cycle system. Turbo-Brayton refrigerator is a key component for closed cycle system. Those two cooling systems are focused in this article. And, each design and component of the cooling system is explained.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.4
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• pp.172-177
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• 2005

The testing and evaluating shunting rates of operating substations have become difficult recently due to various factors including increased fault current, limited area of urban substations and construction of substations in mountain location. In this paper, we have analysed the computation and measurement method of shunting currents that be applied grounding system maintenance of power substations. Also, simple and detailed test methods using 70Hz current injection are explained. A computer program is developed for a study on the shunting properties such as grounding impedance and shunting rates of grounding current, and the simulation results are compared with the measurement data to prove validity and effectiveness of the program and measurement method under commercial operation of a GIS type model substation respectively.

• Proceedings of the KIEE Conference
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• 2000.11a
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• pp.232-235
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• 2000

Design and experiments of a nondestructive system to inspect deterioration of ACSR-OC (ACSR Outdoor Cross-linked Polyethylene Insulated Wire usually used in HV overhead distribution lines presented in this paper. ACSR-OC conductor built to pollutants air for a long period would be easily progress to corrode so that it may lead to the reduction of the effective cross section area of conductors. A fault diagnosis system consisting of a solenoid sensor, a constant current source with RF frequency signal processing unit and a motor driver/controller designed and implemented. This instrument can dot the sensor output variation due to deterioration corrosion, continuously. As a result, it was shown such corrosion detector can readily be utilized estimating the diameter change due to deterioration overhead distribution lines and in giving an warning or inform before severe aged conductor lead to fail.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.257-260
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• 1997

Bluetooth is the most promising network paradigm which ca open the new area in the information technology. Especially, bluetooth can link all the electrical products and PCs(Personal Computer) to cellular phone or PDA. In this paper, the data from ECU which are gathered by scanner are communicated between tow PCs using the bluethooth modules. The acquired data are ECU's self diagnosis signal and sensor output signal. Self diagnosis signals are very important to check the ECU's state and sensor output signals. Using these data, the possibility of wireless communication with ECU is developed and verified. Protocol stack of bluetooth is L2CAP through HCI and wireless communication software of ECU's signal is developed using VC++ in Windows 98 environment.