• Proceedings of the KSR Conference
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• 2007.05a
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• pp.214-218
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• 2007

With the development of high speed railway, traction motors play a critical role in the operation of railway vehicle. This paper describes the use of 1000 pF coupler as a on-line partial discharge (PD) measurement for the assessment of railway traction motor. The PD tests are performed with developed PD analyzer and the 5 model coils such as thermal, electrical, mechanical and environmental aging respectively at various AC voltages. On-line PD tests using 1000 pF couplers show that PD patterns can be detected successfully at 2.3 kV.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.223-226
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• 2007

In the electrical railway, for the improvement of a train speed, it is necessary to study not only the dynamic behaviors of overhead catenary system but the fatigue behaviors of components for a safety assurance according to the increase of vibration level. One of the critical components in the system is a dropper. Therefore, the dynamic force acting on a dropper was measured in the Chungbuk Line and analyzed to figure out the dynamic characteristics the dropper. And in order to assure the safety of dropper clamp and cable, we proposed a test facility as well as test method based on the test results For the further study, we will measure the dynamic forces in the conventional line and high-speed line and make up the test condition, so that the safety of dropper clamps can be assured.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1918-1923
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• 2010

In electic railway, 25kV is applied to AC sections of overhead contact lines and pantographs of Korea Train eXpress(KTX) make contact at speeds of 300km/h. Thus, there is a need to utilize wireless, optic, contact-less sensors to implement condition monitoring systems. This paper is based on describing and analyzing the condition monitoring system implementation technologies for efficient catenary current ratio characteristic assessment. The conclusion of this paper should be widely applied to design, diagnosis, completion of construction, current collection status, fault diagnosis, and selection of contact wires and suspension wires.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.25-29
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• 2010

Safety of railroad is result of reliability which is received from test & evaluation of system. Railroad system is consisted of various sub system such as vehicle, supply of electric power, signal, communication, rail track construction, operation. To secure safety of railroad, evaluation about parts, assembly, sub system, whole system etc.. that compose railroad is essential. In this paper, I wish to describe for results that analyze korean tilting vehicle's derailment coefficient developed by national research achievement. Confirmed that is possible even if speed up, curved line department running speed that estimate korean tilting vehicle's running safety in curved line track of Jungang Line about 20 km/h than present operating speed.

• Journal of Fisheries and Marine Sciences Education
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• v.15 no.2
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• pp.193-205
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• 2003

In this study concerns of parents of gifted children were analyzed. More specifically, this study attempted to classify concerns of parents of gifted children into categories and prioritize concerns in terms of frequency parent indicated. Fifty-two parents whose children are gifted participated in this study and completed open-ended questionnaire. Collected data were analyzed using content analysis and frequency analysis. The results of this study revealed that concerns of parents of gifted children were classified into six categories and sixteen subcategories, and personal trait among six categories was most frequently indicated by parents. The implications of these results for educational and counseling practice were discussed with several limitations of this research and suggestions for future research were made.

• Annual Conference on Human and Language Technology
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• 1996.10a
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• pp.452-463
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• 1996

의존 문법을 사용한 의존 파싱에서 기본적인 단어(품사정보)들 사이의 의존 관계 검사에 의한 파싱 방법은 불필요한 의존 관계의 생성을 가져온다. 이러한 과생성을 해결하기 위하여 파싱 단계에서 보다 정교한 의존 파싱을 통해서 불필요한 의존 관계의 생성을 최소한으로 줄이는 방법에 대한 연구가 필요하다. 본 논문은 의존 파싱에서 최소한의 의존 관계를 생성하기 위하여 후보 의존소가 지배가능경로 상에서 술어 지배소와의 의존 관계 검사 시에 술어의 하위범주화 정보를 이용하는 효율적인 의존 파싱 방법을 제안한다. 이것은 의존 파싱의 다음 처리 단계인 의존 제약의 적용에 훨씬 부담을 덜어 줄 수 있다.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05b
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• pp.823-830
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• 1998

본 연구에서는 미국, 프랑스, 일본의 고온구조 설계지침서의 크립-피로 손상평가 방법을 살펴보고 고온하중을 받는 불연속 구조물에 대하여 범용 유한요소 해석코드인 ANSYS와 ABAQUS를 이용한 열전달 및 응력해석을 수행하여 각국의 코드 절차에 따른 크립-피로 손상 평가를 하였다. 이들 결과를 점소성 비탄성 구성식을 적용한 비탄성해석 결과와 비교평가하였다. 본 연구에서 분석한 불연속 구조물의 경우에 대한 평가 결과 미국의 ASME Subsection NH에 의한 방법이 비탄성 해석결과에 가장 가까운 결과를 주며, 일본의 BDS에 따른 평가방법은 적용성이 가장 편리함을 알 수 있었다.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05b
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• pp.837-843
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• 1998

This paper presents the thermomechanical and fracture mechanics evaluation procedure of thermal striping damage on the secondary piping of LMFR using Green's function method and standard FEM. The thermohydraulic loading conditions used in the present analysis are simplified sinusoidal thermal loads and the random type data thermal load. The thermomechainical fatigue damage was evaluated according to ASME code subsectionNH. The analysis results of fatigue for the sinusoidal and random load cases show that fatigue failure would occur at a geometrically discontinuous location during 90,000 hours of operation The fracture mechanics analysis showed that the crack would be initiated at an early stage of the operation. The fatigue crack was evaluated to propagate up to 5 ㎜ along the thickness direction during the first 944 and 1083 hours of operation for the sinusoidal and the random loading cases, respectively.

• Natural Product Sciences
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• v.8 no.1
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• pp.26-29
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• 2002

The MeOH extract of Sorbus commixta (Rosaceae) exhibited strong DPPH radical scavenging activity, and through activity-guided fractionation two antioxidant compounds were isolated and identified as $catechin-7-O-{\beta}-D-xylopyranoside$ (1) and $catechin-7-O-\;{\beta}-D-apiofuranoside$ (2) by physicochemical and spectrometric methods. To evaluate the antioxidant effect of these compounds, some in vitro tests, such as the DPPH radical scavenging activity test, the superoxide radical scavenging activity test and the lipid peroxidation inhibitory activity test, were performed. Compounds 1 and 2 showed stronger activities than both a-tocopherol and butylated hydroxy anisole (BHA) in each assay.

• Korean Journal of Pharmacognosy
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• v.17 no.2
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• pp.184-188
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• 1986

The preliminary antifertility test of Dictamnus albus(Rutaceae) showed that a methanol extract of root bark decreased fertility in rats when administered orally on days $1{\sim}10$ postcoitum. Hexane, chloroform, butanol and aqueous fractions from the methanol extract, were tested to produce the result that only the hexane fraction exhibited positive activity. The hexane fraction was subfractionated into acidic, alkaloidal and neutral subtractions and tested. Neutral subtraction showed positive activity. From the neutral subtraction, fraxinellone was isolated as an active principle. The timed-dosing experiments revealed that antifertility activity of fraxinellone appeared to be exerted after tubal exit of the ova to prevent implantations.