• Journal of the Korea institute for structural maintenance and inspection
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• v.12 no.1
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• pp.91-100
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• 2008

Multi-stepwise Thermal Prestressing Method(TPSM) is a newly proposed prestressing method, which is combined the external prestressing method and the external bonding method. Multi-stepwise thermal prestressing force is induced by cooling process of cover-plate in the multi-stepwise temperature distribution after the cover-plate being bolted to the girder. In this study, the heating capacity test of the developed heating system for applying the multi-stepwise TPSM effectively and multi-stepwise TPSM inducing test of H-beam is performed. Also, a field test of the rhamen type temporary bridge is carried out to evaluate the effect and application of the multi-stepwise TPSM. Truck load was loaded and compared with the structure analysis results.

• Construction Engineering and Management
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• v.8 no.6
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• pp.69-73
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• 2007

• Proceedings of the Korean Nuclear Society Conference
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• 1999.05a
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• pp.404-404
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• 1999

• The Korean Journal of Applied Statistics
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• v.28 no.2
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• pp.343-351
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• 2015

We introduce how to fit random effects models via a SRC-Stat statistical package. This package has been developed to fit double hierarchical generalized linear models where mean and dispersion parameters for the variance of random effects and residual variance (overdispersion) can be modeled as random-effect models. The estimates of fixed effects, random effects and variances are calculated by a hierarchical likelihood method. We illustrate the use of our package with practical data-sets.

• Proceedings of the Korean Information Science Society Conference
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• 2001.10b
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• pp.544-546
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• 2001

움직임에 따른 변형을 실시간으로 처리하는 것은 가상 현실이나 게임 제작 분야에서 절실히 요구되고 있다. 반면에 캐릭터 등이 착용한 스커트나 바지 등과 같이, 복잡한 변형 특성을 가지는 옷감의 변혁은 캐릭터의 움직임에 따른 변형을 원하는 시간 내에 자연스럽게 생성하기가 쉽지 않다. 본 논문에서는 많은 수의 이산점을 필요로 하는 복잡한 변형을, 실시간적 처리를 고려하여 다단계로 시뮬레이션하는 방법을 제안한다. 제안하는 방법은 방향을 가진 표면 요소로 기본 frame을 구성하여 이들의 시뮬레이션 결과로 비교적 사실적인 표면 전체의 실루엣을 얻고, 이를 세분화시킴으로써 움직임에 따른 세부적인 변형을 생성한다. 기존의 시뮬레이션 중심의 계층적 방법과는 달리, 변형된 기본 프레임의 유한 요소간에 작용하는 움직임과 위상 관계를 기하학적으로 해석함으로써, 움직임에 따른 표면의 세부적인 모양을 얻어 낼 수 있다. 본 논문의 결과로 캐릭터의 돌발적인 움직임에도 안정적이면서 그럴 듯한 움직임을 생성하며, 움직임에 따른 자연스러운 모양을 실시간에 생성할 수 있다.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 1990.10a
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• pp.13-16
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• 1990

균일한 positive column의 상세한 이론이 충돌 단면적 곡선과 공진 방사 그리고 다단계 여기(multistage)와 이온화 과정을 고려하여 0.5에서 5mmHg 압력에서 수은과 희유가스(rare-gas)가 혼합되어 있는 D.C.형광 램프 방전에 대해 전개된다. 온도와 이온, 비여기원자, 여기원자의 밀도가 수치해석에 의하여 계산된다.

• Journal of the Korean Society for Railway
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• v.19 no.2
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• pp.170-186
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• 2016

This paper introduces a multi-phase fuzzy risk graph model, representing a method for determining for SIL values for railway industry systems. The purpose of this paper is to compensate for the shortcomings of qualitative determination, which are associated with input value ambiguity and the subjectivity problem of expert judgement. The multi-phase fuzzy risk graph model has two phases. The first involves the determination of the conventional risk graph input values of the consequence, exposure, avoidance and demand rates using fuzzy theory. For the first step of fuzzification this paper proposes detailed input parameters. The fuzzy inference and the defuzzification results from the first step will be utilized as input parameters for the second step of the fuzzy model. The second step is to determine the safety integrity level and tolerable hazard rate corresponding to be identified hazard in the railway industry. To validate the results of the proposed the multi-phase fuzzy risk graph, it is compared with the results of a safety analysis of a level crossing system in the CENELEC SC 9XA WG A0 report. This model will be adapted for determining safety requirements at the early concept design stages in the railway business.

• Journal of the Korean Operations Research and Management Science Society
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• v.25 no.4
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• pp.27-44
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• 2000

In this study we consider a spares provisioning problem for repairable items in which a parts inventory system is incorporated. If a machine fails, a replacement part must be obtained at the parts inventory system before the failed machine enters the repair center. The inventory policy adopted at the parts inventory system is the (S, Q) policy. Operating times of the machine before failure, ordering lead times and repair times are assumed to follow a two-stage Coxian distribution. For this system, we develop an approximation method to obtain the performance measures such as steady state probabilities of the number of machines at each station and the probability that a part will wait at the parts inventory system. For the analysis of the proposed system, we model the system as a closed queueing network and analyze it using a product-form approximation method. A recursive technique as well as an iterative procedure is used to analyze the sub-network. Numerical tests show that the approximation method provides fairly good estimation of the performance measures of interest.

• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.413-416
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• 2006

The power source of an AC-PDP fur sustainer circuit is operated in high-voltage and high frequency switching during the process required to achieve the gas discharge current to generate light in a PDP panel. Since PDP has the characteristics of a pure capacitive load, the displacement current that occurs during charge and discharge generates considerable reactive power. An auxiliary circuitry called Energy Recovery Circuit (ERC) reduces the capacitive displacement current. However, this auxiliary topology also bears high stress in its components. In this paper, a multilevel voltage wave shaping sustainer circuit with auxiliary ERC characteristics for an AC-PDP driver is proposed. A comparative analysis and experimental results are presented.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1998.06b
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• pp.19-27
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• 1998

박판금속성형공정을 통하여 컴퓨터를 이용한 계산방법으로 효율적이고 정확하게 해석할 수 있는 박판성형해석시스템인 SAIT_STAMP를 개발하였다. 또한 이를 현업문제에 적용하여 금형의 개발기간과 비용을 줄이고 성형품 품질저하 문제들을 해결하는데 이용하였다. SAIT_STAMP 는 성형해석, 성형후해석 프로그램과 전·후 처리기로 구성이 되어있다. 금형과 재료의 접촉 및 마찰을 고려한 새로운 접촉처리방법을 성형해석에 적용하여 해석속도와 해석정확도를 향상하였고 다단계성형 및 유압성형 등 박판성형에 필요한 대부분의 기능을 개발하여 적용하였다. 성형후해석은 성형해석의 결과를 토대로 스프링백해석을 수행한다. Visual C++을 사용하여 개발된 전·후 처리기는 window 95N/T 환경의 PC에서 수행된다. 개발된 프로그램을 이용하여 현업 문제에 적용 해석하였으며 상용S/W 대비 우수한 결과를 얻었다. 현재 삼성내 9개 관계사에서 설치되어 사용중이며 프로그램의 대외신뢰성확보를 위해 대학과 비경쟁업체에 프로그램을 설치하여 프로그램을 설치하여 프로그램의 시험과 성능향상을 하고 있다.