• 제어로봇시스템학회:학술대회논문집
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• 1993.10b
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• pp.245-250
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• 1993

In this paper we propose two feedfroward unbalance compensation algorithms, they accommodate changes of rotor dynamics including rotating speed. The first one determine the compensating signals by identifying system dynamics successively. Whereas, the second one is more primitive like PID algorithm without identifying system dynamics.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.10a
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• pp.383-384
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• 2006

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.10a
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• pp.485-491
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• 1999

A burr is formed in every corner of parts as a result of machining, which produces undesirable edge geometry and influence deeply to surface quality of workpiece. Therefore these burrs must be removed certainly. The cost of removing these burrs is directly proportional to their size. Burrs have been among the most troublesome obstruction to high productivity and automation of machining processes. The proper selection of cutting condition and tool geometry will be helpful to reduce the occurrence of burrs. In paper will observe burr formation along helix angle in end milling and certificate experimentally mechanics relation of helix angle and burr formation.

• Journal of The Korean Astronomical Society
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• v.32 no.1
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• pp.17-39
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• 1999

We investigate dynamical evolution of globular clusters with multi-mass component under the Galactic tidal field. We compare the results with our previous work which considered the cases of single-mass component m the globular clusters. We find the followings: 1) The general evolutions are similar to the cases of single-mass component. 2) There is no evidence for dependence on the orbital phase of the cluster as in the case of single-mass component. 3) The escape rate in multi-mass models is larger than that in the single-mass models. 4) The mass-function depends on radius more sensitively in anisotropic models than in isotropic models.

• Journal of Welding and Joining
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• v.20 no.4
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• pp.407-413
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• 2002

용접기술은 두 가지 재료를 효율적으로 신뢰성 있게 접합시킬 수 있기 때문에 다른 어떤 기술보다 널리 사용되고 있으며, 높은 부가가치를 가져다 준다. 용접계에서는 용접이 국내 산업에 아주 중요한 역할을 담당하고 있다고 생각하고 있으며, 이제 21세기에 접어들어서 우리 용접계의 현위치를 파악하고 새로운 장을 열어야 할 때이다. 미국에서도 이러한 준비의 일환으로 에너지성(Department of Energy)의 주도하에 Welding Vision 2020라는 명제를 걸 고 용접분야의 장래에 대한 심포지움과 토의를 하였다. 이 토의의 중심 주제는 20년 후의 용접계의 위상을 그려보며 장기적 연구 분야, 산학계의 정책 방향 등을 모색하였다 여기서 모아진 의견은, 용접계의 발전적인 진전을 위해서는 향후 2020년까지 다음과 같은 숙제들을 극복해야 된다는 것이었다 많은 산업분야에서 용접이 생산 분야의 주된 작업으로 인식시키는 것 - 용접이 용접 기능사의 재능에 의존도를 줄이고 과학적인 용접 기술 도입과 용접 기능사의 체계적 훈련 - 용접 작업환경 개선 - 용접을 과학적 고기술이라는 것으로 일반인들의 인식을 변화 시킴 - 신소재 개발연구시 용접이 같이 고려될 수 있는 환경 조성 - 훌륭한 인재 양성 및 재교육. 본고에서는 미국 용접계에서 분석한 자료들과 장래 연구되어져야 할 방향 및 분야들을 소개하고 현재 진행중인 자료 수집 및 분석의 진행 상황 및 용접계의 현 위치를 파악할 수 있는 몇 가지 자료들을 소개한다. 아울러, 용접계에서 리더쉽을 발휘해야 될 분야중의 하나이며 현재 많은 전문연구가 필요한 용접 역학(Welding Mechnics) 중의 용 접부의 안정성 평가(Integrity Assessment of Welded Joint)에 대한 과제와 연구 동향을 소개하고자 한다.

• Journal of Welding and Joining
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• v.6 no.2
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• pp.19-29
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• 1988

This paper reports on the elatic-plastic analysis and fracture behavior of cylinder with outer surface crack which is under external or internal pressure. For the studuty of crack length effects in cylinder, ratios of crack lengths to finite thickness (a/t) are dertermined 0.3, 0.4, 0.5. For the study of curvature effects in cylinders, ratios of mean diameter to finite thicknees (Rm/t) are determined 10.0, 15.0, 20.0. Analysis is conduceted using the theory of fracture mechanics and two dimensional finite element solution assuming the axi-symmetrical plane strain conditon. Main results of this study are as follows. 1) It is known from this paper that elastic-plastic strain is initiated near crack tip and enlarged between crack tip and inner side of cylinder. 2) $K_{1}$ of cylinder under external or internal pressure is evaluated memebrane stress .root..pi.* crack length. The results of this study are inclined to Lomacky's results and Kobayshi's result. 3) Distribution of stress near crack tip is looked higher than of other zone, as crack length of equal model is longer, and as diameter of cylinder is longer. 4) When other conditions are equal, displacemenet near crack tip is looked duller, as length is longer.

• Fire Science and Engineering
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• v.27 no.1
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• pp.60-65
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• 2013

From an accident at 2:00 a.m. in November 2nd, 2012 that one fire-fighter died while suppressing the E land World Inc. Fire in Bupyeong-Gu, Incheon, we concluded the problem and the improvement method of using the wireless communication (the two-way radio) that the fire safety officer and the safety crew use when identifying the safety of the fire scene. And after the investigation, we could find that the communication between the fire safety officer and the safety crew was difficult in the scene of the fire by voice because of much noise, so they could rely solely on the wireless communication. Therefore, we investigated the wireless communication and its frequency now used in Incheon Fire Safety Devision. Also, we compared with those of the military and the police. As a result, by making use of the wireless communication and its frequency currently possessed in Incheon Fire Safety Division, we found that the fire safety officer and the safety crew rescuing people at the risk of their own life in the various fire scene can communicate effectively.