• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.2418-2423
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• 2005

Hard Disk Drive (HDD) test system is the equipment for the final test of HDD product by iterative read/write/seek test. This paper proposes an expert system for the fault diagnosis of HDD test systems. The purposed expert system is composed with two cascade inference, fuzzy logic and conventional binary logic. The fuzzy logic determines the possibility of the system fault using the test history data, then, the binary logic inferences the fault location of the test system. The proposed expert system is tested in SAMSUNG HDD product line, KUMI, KOREA, and shows satisfactory results.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.2424-2429
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• 2005

Hard Disk Drive (HDD) test system is the equipment for the final test of HDD product by iterative read/write/seek test. This paper proposes an expert system for the fault diagnosis of HDD test systems. The purposed expert system is composed with two cascade inference, fuzzy logic and conventional binary logic. The fuzzy logic determines the possibility of the system fault using the test history data, then, the binary logic inferences the fault location of the test system. The proposed expert system is tested in SAMSUNG HDD product line, KUMI, KOREA, and shows satisfactory results.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.399-401
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• 2000

Recently polymer insulators are being used for outdoor high voltage applications. Polymer insulators for transmission and distribution line have significant advantages over porcelain and glass insulators, especially for ultra-high voltage(UHV) transmission lines. Their advantages are light weight, vandalism resistance and hydrophobicity. In this paper, polymer line post insulator has been designed and investigated electric field distribution by FEM. Designed LP insulators have been tested as insulator performance test, such as power frequency voltage test, lightning impulse voltage test, artificial pollution test and flexural load test.

• The Transactions of the Korean Institute of Power Electronics
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• v.28 no.1
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• pp.76-81
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• 2023

A new test circuit for an MMC-based valve HVDC power converter is proposed. The proposed scheme satisfies the required clauses from IEC-62501. The valve test current contains second harmonic component and DC offset as well as a fundamental component that is quite similar to the real operating arm current of MMC based HVDC power system. The structure of the proposed test circuit is simple compared to conventional test circuits. Furthermore, the power supply voltage rating of the proposed test circuit is reduced dramatically around 20% of the conventional scheme with the same current rating. The validity of the proposed test circuit is verified through simulation and experimental results.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.08a
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• pp.19-22
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• 2003

In the response to increasing the demands for electrical energy, much effort aimed to develop and commercialize 1MVA HTS power equipments that is supported by a grant from center for Applied Superconductivity Technology of the 21st Century Frontier R&D Program funded by the Ministry of Science and Technology is going on in Korea. For the development, the cryogenic insulation and winding insulation of it in this paper are discussed. In the first many types of dielectric insulating tests were carried out. In detail Breakdown characteristics of $LN_2$, FRP and turn insulating films, flashover characteristics along the FRP surface in $LN_2$ were verified after distinguishing insulation components in HIS windings. And then model windings were designed and insulation test was conducted. These included a AC withstand voltage test of 50kV rms and a lightning impulse test of 150kV at peak.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.11
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• pp.1651-1656
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• 2017

This paper deals with the thermal and mechanical properties of ceramic coating material for bus bars. A ceramic coated samples were prepared for the mechanical properties test. There are two types of samples. One is a square shape and the other is a busbar shape. Each sample was deteriorated for 30 days to compare the thermal and mechanical properties with the non-degraded samples. Two thermal properties tests are TGA and flammability tests, and four mechanical properties tests are drop impact test, cross cut, tensile test, and bend test. The ceramic coating material was never damaged by impact and did not separate from aluminum in the cross cut test. In the tensile test, the breakage of the insulating material did not occur until aluminum fractured, and the breakage of the insulating material did not occur until the maximum load in the bending test. The decomposition temperature (melting point) of the ceramic coating material was higher than that of other epoxy insulators. This ceramic coating material is nonflammable and it has excellent fire stability.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.3
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• pp.485-491
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• 2015

This paper shows the design improvement and test model of FAU (Frequency Analysis Unit) in PDD (Partial Discharge Diagnosis system) for 800kV GIS (Gas Insulated Switchgear). We found some problems during operation of previous FAU, such as the aging of fiber-optic converter that can cause communication error, the malfunction of signal analysis circuit etc. And then we solved those problems by design improvement and verified the performance through type test. To monitor partial discharge, the performance of UHF sensor is important but the performance of frequency analysis unit is also very important. So we solved communication error, the malfunction of signal analysis circuit and then increased the operation reliability of FAU by improving fiber-optic converter and signal analysis circuit. Accredited testing laboratory carried out the performance verification test according to performance test criteria and procedure of reliability test standards, IEC-60225, 61000 and 60068 etc. We confirmed the test results which correspond with the performance test criteria.

• The Journal of Korean Physical Therapy
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• v.16 no.3
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• pp.97-111
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• 2004

This study, adopting the pretest-post test experimental study, is designed to find out how the functional electrical stimulation makes effect on the balance of a patient with spasticity of the ankle plantarflexor muscle caused by hemiplegic after stroke. The 46 subjects for this study were randomly sampled out of the patients who were hospitalized from September 1, 2003 to November 30, 2003 in H sanitarium in Yangpyung. The patients were with spasticity of the ankle plantarflexor muscle caused by hemiplegic after stroke and able to walk without supporting implements. The purpose of the study is firstly to analyze the change of ROM, FRTof a patient with spasticity of the ankle plantarflexor muscle when the functional electrical stimulation is applied and secondly to find out how the sex, age, height, weight, part of the diagnosis, duration of pain, experience of relapse and getting hurt from a fall of a patient make effect on the change. The experimental group for the study is divided into two to compare the differences of the effect. The exercising treatment only was performed for the conrtol group, and the functional electrical stimulation to the ankle dorsiflexor muscle as well as the exercising treatment was applied to the experimental group. The ROM test was performed to check the range of motion of the ankle with a double armed universal goniometer. The test was done 3 times to take an average. FRT were performed to check the balance. The statistical test was conducted using the SPSS 10.0/PC program by means of the following methods: χ2-test and t-test for testing homogeneity between the groups; paired t-test, independent sample t-test, F-test, and two-way ANOVA for analyzing the changes before and after the treatment. The levels of statistical significance of all the data were maintained at p<.05. According to the test, ROM has more decreased in experimental group than in control group when the functional electrical stimulation was applied only to the experimental group. However, the significant statistic difference was not shown (p=.059). FRT showed remarkable differences in the experimental group compared to the control group, showing the significant statistic difference (p=.000). On the one hand, the change of ROM, FRT related with the sex, age, height, weight, part of the diagnosis, and experience relapse was a meaningless minimum value. The change of ROM related to the duration of pain and the experience of falling down was also meaningless. However, FRT showed significant statistic difference (p<.05). According to the test above, the application of functional electrical stimulation to a patient with spasticity of the ankle dorsiflexor muscle caused by hemiplegic after stroke makes significant effect on the balance of a patient, but the result has nothing with the sex, age, height, weight, part of the diagnosis, duration of pain, experience of relapse and getting hurt from a fall of a patient. However, it is regarded to give contribution to the balance improvement of a patient. Therefore, this study expects to be a valuable clinical material for a patient with spasticity.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.849-851
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• 2001

This paper presents experimental method of parameter measurement and starting characteristics of 3 phase induction motor. Equivalent circuit parameters measured by DC test, the blocked rotor test, and no load test were used as the input data for computer simulation. Starting characteristics, such as starting current and torque were analyzed through computer simulation by Matlab, and the simulation results were compared with experiment using strain gauge attached on motor shaft. We conform that experimental results are very similar to that of simulation.

• Journal of Electrical Engineering and information Science
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• v.3 no.1
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• pp.45-50
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• 1998

This paper deals with some characteristics of a nondestructive eddy current detector to measure OPGW(Composite overhead ground wire with optical fiber) corrosion. This detector is designed to automatically run on OPGW and to continuously inspect the corrosion of the line. The impedance of the eddy current coil changing by any corrosion phenomenon of OPGW is analyzed. Several performances of the detector are described and experimental procedures and test results are also given. As a result, it is shown that the implemented detector can be measured some quantitative data for crack, broken wires or severe deteriorations in OPGW. This nondestructive test method would be applied to improve the reliability and efficiency of transmission line in service.