• Journal of Electrical Engineering and Technology
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• 제4권1호
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• pp.123-130
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• 2009

The partial discharge (PD) measurement is a very effective method to assess the winding insulation condition of high-voltage machines, since most of the insulation failure processes are directly or indirectly caused by PD. On-line PD measurements, which can detect insulation defects of winding in the early stages on rotating machines in operation, have been accepted as the most important technique. The epoxy mica capacitive coupler is currently and extensively used for on-line detection of PD pulses of high-voltage rotating machines. To evaluate the feasibility of developing a capacitive coupler that is easier to manufacture at a lower cost compared to epoxy mica couplers, a 100pF capacitive coupler made of ceramic material is designed, fabricated and tested for on-line PD measurements of 23 kV electrical machines. A series of electrical tests and accelerated aging tests are performed on the ceramic coupler to evaluate the performance requirements, long-term reliability and thermal stability for in field application. The test results show that the newly developed ceramic coupler provides equal and improved performance at a lower cost compared to epoxy mica couplers, and estimated voltage life is anticipated to surpass 100 years.

• 산업경영시스템학회지
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• 제22권49호
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• pp.135-142
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• 1999

The objective of this paper is to provide an automatic color image testing system capable of synthetically testing a color element like a color tone and a luminance for a color image displayed on the screen, using a CCD camera and a microprocess. The system consists of a CCD camera, a line conveyor, a camera driving part, a remocon, a remote sensing part, a display and a PC including a color vision board and a CPU board. By applying the system to a process, reliability for a testing result can be improved and the absolute criterion to judge a part can be made.

• 한국철도학회논문집
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• 제3권3호
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• pp.154-160
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• 2000

The automatic/driverless operation which are great important techniques in metro railway are required to increase higher safety, greater reliability, and transport capacity. To satisfy such demands, we must have the system design and testing technique for the railway system operation. These techniques are related to the onboard train control and communication systems which include TCMS(Train Control and Monitoring System), ATO(Automatic Train Operation), ATC(Automatic Train Control), and TWC(Train to Wayside Communication). These sub-systems must be interfacing with not only each others but also the signal system on the ground. We tested the train control system on Test line that has been developed on the basis of the standardized type EMU for korea railway systems. This test line which is located in Sangju, have been constructed for testing 7 ＆ 8 line of Seoul Metro railway.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2000년도 춘계학술대회 논문집
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• pp.172-179
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• 2000

The automatic/driverless operation which are great important techniques in metro railway are required to increase higher safety, greater reliability, and transport capacity. To satisfy such demands, we must have the system design iかd testing technique for the railway system operation. These techniques are related to the onboard train control and communication systems which include TCMS(Train Control md Monitoring System), ATO(Automatic train Operation), ATC(Automatic train Control), and TWC(Train to wayside communication). These sub-systems must be interfacing with not only each others but also the signal system on the ground. We tested the train control system on Test line that has been developed on the basis of the standardized type EMU for korea railway systems. This test line which is located in Sangju, have been constructed for testing 7 ＆ 8 line of Seoul Metro railway.

• 비파괴검사학회지
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• 제22권6호
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• pp.637-642
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• 2002

An arc-shaped line array slit has been used for the laser generation of focused Lamb waves. The spatially expanded Nd:YAG pulse laser was illuminated through the arc-shaped line array slit on the surface of a sample plate to generate the Lamb waves of the same pattern as the slit. Then the generated Lamb waves were focused at the focal point of which distance from the slit position is dependent on the curvature of slit arc. The proposed method showed better spatial resolution than the conventional linear array slit in the detection of laser machined linear defect and drill machined circular defect on aluminum plates of 2mm thickness. Using the focused waves, we could detect the linear defect and the circular defect with the improvement of spatial resolution. The method can also be combined with the scanning mechanism to get an image just like by the scanning acoustic microscope(SAM).

• 비파괴검사학회지
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• 제26권3호
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• pp.181-189
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• 2006

A 2D finite-element numerical simulation has been developed to investigate the generation of ultrasonic waves in a homogeneous isotropic elastic slab under a line-focused laser irradiation. Discussing the physical processes involved in the thermoelastic phenomena, we describe a model for the pulsed laser generation of ultrasound in a metal slab. Addressing an analytic method, on the basis of an integral transform technique, for obtaining the solutions of the elastodynamic equation, we outline a finite element method for a numerical simulation of an ultrasonic wave propagation. We present the numerical results for the displacements and the stresses generated by a line-focused laser pulse on the surface of a stainless steel slab.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.2286-2291
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• 2011

Technology on the rolling stock is very composition and system engineering. We have to consider to many parameters on the rolling stock design. High speed train is interface between rolling stock and infra system of rail, signal, communication etc. For many years testing operation has experienced substantial growth based on various advanced new technology. Recently some problems was clearly stated on effective management, practical use and testing operation of the the rolling stock on the technology change. This paper presents some results of the study on necessary requirements of the operation testing for rolling stock technology change. We propose a general plan to suggest the operation testing and the parameters of the rolling stock on the technology change in the text.

• 대한전자공학회논문지SD
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• 제46권9호
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• pp.14-24
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• 2009

System on panel 프레임 버퍼를 위한 메모리 셀 어레이와 주변회로가 설계되었다. 또한, system on panel 공정의 낮은 yield를 극복하기 위해, 블럭 단위의 parallel test 방안이 제안되었다. 기존의 메모리 테스트 보다 빠르게 fault detection이 가능하며, 다양한 embedded memory나 일반 SRAM 테스트 분야에도 적용 가능하다. 또한 기존의 다양한 test vector pattern이 그대로 적용될 수 있어 fault coverage가 높고, 최근의 추세인 hierarchical bit line과 divided word line 구조에도 적용될 수 있다.

• Journal of Electrical Engineering and Technology
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• 제13권2호
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• pp.881-885
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• 2018

In order to develop a gas circuit breaker (GCB), the breaking performance of the short line fault (SLF) should be prioritized over that of the breaker terminal fault (BTF). In brief, it is necessary to evaluate the thermal characteristics of the insulating gas that is filled in a GCB. In the process of developing a GCB, many companies use the simplified synthetic testing facility (SSTF).In order to evaluate the SLF breaking performance of a GCB with a long minimum arcing time, a modifications to the conventional SSTF was proposed. In this study, we developed the SSTF with a modified transient recovery voltage circuit. The performance of the newly developed SSTF was verified by an $L_{90}$ breaking performance test on a rating combination of 170 kV, 50 kA, and 60 Hz.

• 전기전자학회논문지
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• 제5권1호
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• pp.43-51
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• 2001

메모리의 집적도가 올라갈수록 원치 않는 셀간의 간섭과 동시에 bit-line간의 상호 노이즈도 증가하게 된다. 그리고 높은 고장 검출율을 요구하는 고집적 메모리의 테스트는 많은 테스트 백터를 요구하게 되거나 비교적 큰 추가 테스트 회로를 요구하게 된다. 지금까지 기존의 테스트 알고리즘은 이웃 bit-line의 간섭이 아니라 이웃 셀에 중점을 두었다. 본 논문에서는 NPSFs(Neighborhood Pattern Sensitive Faults)를 기본으로 한 NBLSFs(Neighborhood Bit-Line Sensitive Faults)를 위한 새로운 테스터 알고리즘을 제안한다. 그리고 제안된 알고리즘은 부가 회로를 요구하지 않는다. 메모리 테스트를 위해 기존의 5개의 셀 레이아웃이나 9개의 셀 레이아웃을 사용하지 않고 NBLSF 검출에 최소한 크기인 3개의 셀 레이아웃을 이용하였다. 더구나 이웃 bit-line에 의한 최대의 상호잡음을 고려하기 위해 테스트 동작에 refresh 동작을 추가하였다(예 $write{\rightarrow}\;refresh{\rightarrow}\;read$). 또한 고착고장, 천이고장, 결합고장, 기존의 pattern sensitive 고장, 그리고 이웃 bit-line sensitive 고장 등도 검출될 수 있음을 보여준다.