• The Transactions of the Korean Institute of Electrical Engineers P
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• v.58 no.2
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• pp.214-220
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• 2009

Battery is one of the emergency power and its reliability is a very important to keep up the minimum of building capabilities in case of interruption of electric power. This paper, a comparison was made between three different types of instrument on 30 valve regulated lead acid(VRLA) TYPE 12[V]/100[AH] batteries, and then their indicated measured values(impedance/conductance) were compared with the measured capacity of the battery. As a result, Measured value of instrument is strongly related to battery's capacity in the same group battery and Impedance/Conductance guide line for diagnosis of lead-acid battery's state of health(SOH) is a different from each battery guoup.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.570-571
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• 2011

CTMS(Compact Tower Online Monitoring System), which deals with the polymer insulation arms of new material, is the on-line monitoring system for verifying stability and reliability of a new Compact Tower. CTMS measures real time data from the installed sensors in a Compact Tower and transmission line, air craft warning lights for detecting and determining the life time and the replace cycle of these facilities. This paper introduces how develop the CTMS and proposes how it will be use.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.406-407
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• 2011

The closed-loop distribution system is more flexible and more reliable than radial system. If any type fault occurs, the reliability of system can be better by providing electrical energy through another distribution line. However, it needs protection device coordination of different type. Typically, it is available by using directional overcurrent relay (67). This paper gives a solution about loop protection relay modeling which can be used by the simulation tools.

• Journal of the Korean Society for Nondestructive Testing
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• v.18 no.4
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• pp.313-320
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• 1998

To record and evaluate the flaws which were found during pre-service/in-service inspection performance of nuclear power plants in Korea, the center line beam method described in ASME code and 6 dB drop method stated in CSA code were used. The measured through wall dimensions and lengths by these methods were compared and analyzed in this report. With the measured data analysis, the ekact understanding and use of these methods improves the reliability of flaw sizing and assures the integrity of nuclear power plant components.

• Proceedings of the KIEE Conference
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• 2008.10a
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• pp.95-96
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• 2008

We constructed an on-line PD monitoring system for the 380kV U/G Cable project at the Riyad 9012 substation in Saudi-arabia. The system will be monitoring the termination of the two 380kV XLPE Cables to prevent unexpected failure of the cable insulation. The system had been tested in the laboratory and on-site for detection of various PD signals and reliability of operation. The system distinguish the existence and nonexistence of the partial discharge and then judge the source of partial discharge using automatic PD pattern recognition software.

• Proceedings of the KIEE Conference
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• 2008.04b
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• pp.96-99
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• 2008

On-line condition monitoring is a useful tool for maintaining and extending the longevity of power transformers. An intelligent diagnostic system is desirable for operational safety and reliability. Bringing these concepts together results in a powerful support tool for engineers, reducing the volume of data to deal with, and making the data more meaningful. This paper describes how a multi-agent system for diagnosing the cause of transformer partial discharge activity was coupled with a method of UHF partial discharge monitoring, creating an on-line condition monitoring system. The challenges presented by the on-site environment are discussed, along with the implications for the complete system.

• Journal of Computing Science and Engineering
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• v.3 no.1
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• pp.59-71
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• 2009

While the average-case performance is important for general-purpose applications, worst-case performance is crucial for real-time systems to ensure schedulability and reliability. Recent work has shown that simple prefetching techniques such as the Next-N-Line prefetching can benefit both average-case and worst-case performance; however, the improvement on the worstcase execution time (WCET) is rather limited and inefficient. This paper presents two instruction prefetching approaches that are specially designed to enhance the worst-case performance, including the loop-based prefetching and WCET-oriented prefetching. Our experiments indicate that both instruction prefetching techniques can achieve better worst-case execution cycles than the Next-N-Line prefetching while having various impacts on the average-case performance.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.10a
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• pp.665-668
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• 2000

This paper presents development of a different substance monitoring system base reliable detection between the conveyer belt and hopper used lot materials transport line of steel company. Conventional detection method of a piece of iron separation system is losed the confidence, because of the place with bad surroundings of measurement so much that materials Production line are completely exposed to dust, moisture and vibration. For the solution of this problem, we developed a different substance detection system using the acoustic emittion sensor and one chip microprocessor which is available for bad surroundings and inexpensive. The reliability of the system was estimated by experiment.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.5
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• pp.1068-1073
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• 2004

5 V/500 mA transless type power module was designed by using a semiconductor switching technique for a small-sized electric power source. It used voltage drop type chopper method, and is composed of switching circuit, control circuit, voltage detect circuit, and constant voltage circuit. The switching power module which is designed in this study, showed load regulation of 0.2 V, line regulation of 0.1 V, output ripple of 85 mVp-p, switching frequency of 64.7 kHz, maximum power efficiency of 58 %, and satisfied its reliability and EMC test.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.787-790
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• 2001

Polymer bushing used for overhead line switch was designed and investigated. Requirements of electrical ratings such as partial discharge, ac withstand voltage, impulse voltage and material properties were proposed in accordance with IEEE 386 and pre-standard (PS) 151-146∼147, 170∼180 of KEPCO. The polymer bushing consists of an internal epoxy bushing and external housing made of EPDM rubber. The rubber housing was molded with mold cone. Therefore, the polymer bushing offers several advantages like light weight, good sealing properties, easy installation and excellent performance in contamination. Electric field analysis was also introduced in order to verify the reliability of the design.