• Proceedings of the KSR Conference
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• 2010.06a
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• pp.315-323
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• 2010

It is suggested that the service life of the continuous welded rail(CWR) is estimated by the relationship between the rail surface irregularity according to the accumulated passing tonnage and bending fatigue of welded part in CWR. In this study, it measured bending stress of rail according to the rail surface irregularity in the concrete track on the Seoul Metro. In addition, the relationship between rail surface irregularity and bending stress in concrete track is analyzed by results of the field test. Finally, this study clarified the relationship among bending stress(Y) of rail, train speed(U), rail surface irregularity(v, w) in concrete track. The result of this study is able to use the basis data to establishing the periodic replacements criterion of CWR.

• Journal of the Society of Naval Architects of Korea
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• v.33 no.4
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• pp.75-86
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• 1996

A fatigue life prediction program for multiple planar surface cracks in finite plates and T-fillet joints, based on linear elastic fracture mechanics was developed. This prediction technique include the crack coalescence, mutual interation and the stress intensity concentration effect in welded joints. Total of 44 cases were compared with lida's and Vosikovsky's experimental results and it was found that the present method was a reasonable tool for the predictioin of fatigue life.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.5
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• pp.921-927
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• 1989

One of the most important problems in recent life prediction is to introduce the degradation effects into life prediction procedure. In the present paper, the effect of the material degradation on the fatigue surface crack growth and fatigue life prediction in a 2 1/4 Cr-1Mo steel were investigated. The 2 1/4 Cr-1Mo steel has been used in a plant having operated for over 60000hours and subjected to material degradation due to temper-embitterment. A Monte-Carlo simulation was made on the basis of the data obtained in the experiment in order to determine the P-S-N diagrams of surface crack growth for the degraded and recovered steels.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.163-166
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• 2004

표면 반사파가 존재하는 무향수조 내에서 근접 음향 홀로그래피의 적용 가능성을 살펴보기 위하여 여러 변수의 변화에 따른 음장 예측 수치해석을 수행하였다. 수직 배열 센서 및 수평 배열 센서를 이용하는 경우에 대해 해석하였으며 수직 배열센서를 이용하여 한 면에서 측정하는 경우 표면 반사파에 의한 영향은 무시할 만큼 작은 것을 확인하였다. 수평 배열센서를 이용하는 경우에는 표면 반사파의 영향이 상대적으로 크게 나타나 반사파를 고려하기 위해 두개의 측정면에서의 음압값이 필요하며 직접파와 반사파를 모두 고려하는 경우 음압 예측치의 오차가 적게 나타남을 알 수 있었다.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2012.11a
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• pp.76-77
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• 2012

전기 도금 시스템에서 전산모사 해석을 이용하여 도금층 두께를 정확히 예측하기 위해서 음극 표면의 확산층이 고려된 도금 Simulator를 개발하였다. 특정 형상의 경우 도금액 교반이 원활하지 않아 불균일한 도금이 이루어지는 경우가 있기 때문에 이를 예측하기 위해서는 교반 영향을 나타내는 확산층을 고려해야 한다. 유동해석을 통해 도금액 교반 조건 및 형상에 따른 음극 표면의 유속을 결정하고 유속별 도금액 DB를 구성하여 음극의 위치별 분극곡선을 차별화하여 유동 조건에 따른 확산층 변화를 고려하는 형태로 구현하였다. 유속별 도금액 DB는 실험 데이터 및 해석 데이터를 종합하여 구축하였다. 교반의 영향을 많이 받는 시스템을 대상으로 개발된 Simulator 결과의 타당성을 검증하였고 확산층 적용에 따른 도금 결과의 차이를 확인하였다.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2003.05a
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• pp.94-97
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• 2003

본 연구에서는 반도체제조에 필수적으로 사용되는 플라즈마장비의 성능을 예측.분석하여 개발 시간 및 비용의 절감과 장비의 성능을 극대화 할 수 있도록 이론적 전산모사 환경(VIP-SEPCAD)을 개발하고 있다. VIP-SEPCAD는 플라즈마의 물리.화학적 특성을 예측하는 plasma model, 중성화학종들의 반응 및 유돈 특성을 예측하는 neutral reaction-transport model, particle의 유동 특성을 예측하는 particle transport model, particle의 생성 및 성장 특성을 예측하는 particle formation-growth model, 식각 또는 증착되는 웨이퍼 표면변화를 예측하는 surface evolution model로 구성되어 있다. 현재 개발된 VIP-SEPCAD를 이용하여 산소 플라즈마의 특성과 각종 화학성분들의 분포를 예측하고 particle의 거동에 대하여 분석하였다.

• 한국HCI학회:학술대회논문집
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• 2009.02a
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• pp.418-421
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• 2009

This paper presents a human-machine interaction based on a realtime upper limb motion prediction method using surface electromyography (sEMG). The motions were predicted using an artificial neural network algorithm and sEMG signals which are acquired from five muscles, and then a manipulator was controlled to follow after the predicted motions. Upper limb motions were restricted to 2D vertical plane with the contact condition between a user and an end-effector of manipulator. In order to demonstrate the feasibility of the proposed method, experiments using developed method and using a goniometer were performed. The results showed that the proposed real-time motion prediction method can be implemented a human-machine interaction system.

• Journal of Conservation Science
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• v.32 no.4
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• pp.491-500
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• 2016

Fog is atmospheric in which tiny drops of water vapor are suspended in the air near the ground. Its form, occurrence, etc., change according to the temperature, relative humidity, wind and geographical features of the space around it. In particular, fog tends to occur near a source of water because of temperature and relative humidity difference. These days, climate change is increasingly affecting the occurrence of fog. Therefore the purpose of this study was to investigate how fog affects materials that are part of our cultural properties through outdoor exposure tests and artificial degradation. The degradation evaluation of materials as a function of fog occurrence frequency, showed that the color of metals changed noticeably, whereas dyed silk and Dancheong showed degradation on the surface and color differences but no particular tendencies. Therefore, damage prediction by color differences as a function of fog occurrence frequency was based on metal samples, which showed constant color differences. Through a comparison of the predictive value and color difference by outdoor exposure, the accuracy and applicability of the damage prediction formula was confirmed. If a more complex damage prediction formula is created, it is expected that prediction of the degree of material damage in the field would be possible.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 1999.05a
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• pp.30-31
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• 1999

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2000.11a
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• pp.83-84
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• 2000