• 한국가스학회지
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• 제16권1호
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• pp.22-25
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• 2012

Welding and/or fusion in polyethylene(PE) system made on site is focused on the control of the welding or fusion process to follow proper procedure. The process control is important, but it is not sufficient for the long term reliability of a pipe system. To achieve the rate of failure close to zero, Non Destructive Testing(NDT) is necessary in addition to joining process control. For electrofusion joints several non-destructive testing methods are available. The ultrasonic phased array technique is possible to detect various defects including wire deviations and regions with lack of fusion. In this studies, testing was carried to detect the defect after electrofusion joining of polyethylene piping is utilized by the ultrasonic phased array technique. From testing data, ultrasonic phased array technique is recommended as a reliable non-destructive testing method.

• Journal of Information Technology Applications and Management
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• 제13권4호
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• pp.1-12
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• 2006

Many software reliability growth models(SRGM) have been proposed since the software reliability issue was raised in 1972. The technology to estimate and grow the reliability of developing S/W to target value during testing phase were developed using them. Most of these propositions assumed the S/W debugging testing efforts be constant or even did not consider them. A few papers were presented as the software reliability evaluation considering the testing effort was important afterwards. The testing effort forms which have been presented by this kind of papers were exponential, Rayleigh, Weibull, or logistic functions, and one of these 4 types was used as a testing effort function depending on the S/W developing circumstances. I propose the methology to evaluate the SRGM using least square estimator and maximum likelihood estimator for those 4 functions, and then examine parameters applying actual data adopted from real field test of developing S/W.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1987년도 한국자동제어학술회의논문집; 한국과학기술대학, 충남; 16-17 Oct. 1987
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• pp.619-624
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• 1987

A study on distribution automation system suitable to distribution system of KEPCO has started since 1984, and the field trial system for ADS will be operated for testing. This paper will describe project and planning for field trial of KEPCO.

• Geomechanics and Engineering
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• 제10권4호
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• pp.527-546
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• 2016

This paper discusses improvements of compressibility, permeability, static and liquefaction strengths of in-situ soils by grouting. Both field testing and laboratory evaluation of the on-site samples were conducted. The improvement of soils was influenced by two main factors, i.e., the grout materials and the injection mechanisms introduced by the field grouting. On-site grout mapping revealed the major mechanism was fracturing accompanied with some permeation at deeper zones of sandy soils, where long-gel time suspension grout and solution grout were applied. The study found the compressibility and swelling potential of CL soils at a 0.5 m distance to grout hole could be reduced by 25% and 50%, respectively, due to the grouting. The effect on hydraulic conductivity of the CL soils appeared insignificant. The grouting slightly improved the cohesion of the CL soils by 10~15 kPa, and the friction angle appeared unaffected. The grouting had also improved the cohesion of the on-site SM soils by 10~90 kPa, while influences on the friction angle of soils were uncertain. Liquefaction resistances could be enhanced for the sandy soils within a 2~3 m extent to the grout hole. Average improvements of 40% and 20% on the liquefaction resistance were achievable for the sandy soils for earthquake magnitudes of 6 and ${\geq}7.5$, respectively, by the grouting.

• 비파괴검사학회지
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• 제20권4호
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• pp.322-328
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• 2000

730MHz의 고정 주파수를 방사하는 3소자 안테나 방식의 GPR을 이용하여 자체 제작한 시험장 속에 매설된 다양한 시험편의 검출능력을 조사하였다. 여러 가지 상황에 대한 검출능력을 알아보기 위하여 매설물의 재질, 크기, 매설 깊이에 차이를 두어 실험을 수행하였다. 레이다파의 전파속도를 조절하여, B-scan상의 쌍곡선 패턴의 위치를 실제 매설한 깊이에 정확하게 위치하게 함으로써, 실험결과로부터 얻은 soil(dry)에서의 레이다파의 전파속도가 기존 data와 유사함을 확인하였다.

• 대한전자공학회논문지TC
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• 제40권8호
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• pp.340-348
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• 2003

본 논문에서는 시간영역 결합적분식 (combined field integral equation, CFIE)을 이용하여 도체로부터 산란되는 전자파 과도응답을 무조건적으로 안정되게 해석할 수 있는 새로운 해법을 제안한다. 이 방법은 기존의 MOT (marching-on in time) 기법을 이용하지 않고, 모멘트법으로 공간 및 시간을 분리하여 시험 내적을 적용한다. 삼차원 임의 형태의 도체 구조를 해석하기 위하여 공간영역의 전개 및 시험함수로서 삼각형 벡터 함수를 사용한다. 시간 영역의 전개함수는 지수 감쇄함수를 라게르 함수에 곱하여 정의되며, 이 함수는 시간영역의 시험함수로도 사용된다. 제안된 방법에 의하여 계산되는 도체로부터의 과도응답은 진동없이 안정되었으며, 주파수 영역의 CFIE로부터 계산된 결과와 잘 일치하였다.

• 한국자동차공학회논문집
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• 제18권4호
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• pp.84-91
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• 2010

Owing to revolutionary developments in automobile technologies, a variety of advanced vehicles - hybrid vehicle, hydrogen fuel-cell vehicle, electric vehicle, etc. - emerges recently. The safety is getting more important for developing automobiles. The electro-magnetic compatibility has to be assured, since those advanced vehicles are equipped with various new electronic systems. Electro-magnetic compatibility tests, in general, consist of an EMI(electro-magnetic interference) test and an EMS (electro-magnetic susceptibility) test. We investigated the susceptibility test method suggested in KMVSS (Korean Motor Vehicle Safety Standard) as the EMS test method. A series of experiments results that the above test method should be partially revised to comply with a Korean governmental standard method. In this paper, the some directions of modifications are presented to enhance the quality of the above EMS test method.

• Nuclear Engineering and Technology
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• 제38권5호
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• pp.437-442
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• 2006

European Material Test Reactors (MTRs) have provided essential support for nuclear power programs over the last 40 years. MTRs are now ageing in Europe and they cannot ensure the securing of experimental capability for the next decades. In this context, a new Material Testing Reactor, named Jules Horowitz Reactor -JHR-, operated as an international user-facility, is under development in Europe. The European MTRs context and the JHR objectives and status will be presented. Emphasis will be put on experiments in the field of nuclear fuels and materials irradiation which are developed in the framework of European and international collaboration.

• 비파괴검사학회지
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• 제10권2호
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• pp.43-49
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• 1990

Ultrasonic testing is one of the most useful NDT method for detection of microdefect in the opaque materials. Recently, many applications of the ultrasonic techniques have been extended widely in the new field like electron is and advanced materials. From the result of the experiment, we have hardly found out a crack in the internal parts of the resin and a delamination between chip and resin because of poor performance of the system.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2008년도 추계학술대회 논문집
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• pp.371-374
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• 2008

KEPRI has carried out IEC61850 communication conformance test about the IED trial products. This paper describes dataset conformance testing, one of the IEC 61850-10 conformance test items, and test procedures on IED. KEPRI plans to construct the testing field of IEC 61850 based substation automation system with domestic IEDs confirmed their IEC 61850 communication service including dataset.