• Korean Journal of Construction Engineering and Management
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• v.8 no.3
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• pp.159-167
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• 2007

In this study, the concepts of integrated VE analysis assessment is introduced in order to achieve "Design for Deterioration performance" in design VE phase. For this purpose, a framework for fuzzy reliability based LCC and value analysis model using fuzzy logic based approach for breakwaters Projects is suggested. It is anticipated that the methodology Proposed in this paper can also be utilized in the design and maintenance phase of other facilities where decision making is made for the fuzzy reliability based life cycle cost and value analysis.

• Proceedings of the Korea Multimedia Society Conference
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• 2003.11b
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• pp.699-702
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• 2003

본 논문에서는 무선 인터넷 주요 기술로 관심을 받고 있는 분산데이터 동기화 표준인 SyncML을 이용한 개인정보관리 시스템의(PIMS) 설계 및 구현에 대한 소개하고자 한다. 객체 지향 설계 기법을 사용하여 분석, 설계하여 최적화 된 시스템을 도출하고 그것을 통해 우선인터넷상에서 경량화 된 동기화 최적의 시스템을 설계와 구현하는데도 목적이 있다. 특히 무선인터넷의 여러 제약 사항 특히 데이터의 관리에 있어서의 문제점을 동기화 기술을 통해 많은 데이터를 효과적으로 관리함으로써 대용량의 데이터 베이스와 디바이스에 상관없이 데이터 일관성을 유지하여 지연성 및 복수성에 신뢰성을 유지 할 수 있도록 시스템을 개발하였다.

• Computational Structural Engineering
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• v.6 no.1
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• pp.117-125
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• 1993

In general, the strength and stiffness of laminated composite cylindrical shells are very sensitive to the variation of slenderness parameters, some coupling-stiffness parameters, lamination angles, stacking sequence and number of layers. In this paper, the effects of these factors on the strength and buckling reliabilities of GFRP laminated cylindrical shells are investigated based on the proposed strength and buckling limit state models. As these factors have various and complicated effects on the strength and buckling reliabilities of GFRP laminated cylindrical shells, the results should be incorporated into the design formula such that optimum design technique and design code which provide uniform consistent reliability for balanced design in practice

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2006.10a
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• pp.35-38
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• 2006

디스플레이 산업에 이용되는 적층판(layered plates)의 결합공정 중 냉각공정에서 열팽창계수의 차이로 인해 잔류응력이 발생하고 심하면 적층판에 크랙(crack)이 발생한다. 본 연구에서는 적층판의 결합공정을 대상으로 현상을 분석하고 이 과정을 시뮬레이션하는 해석 프로그램을 개발하였다. 또한 이를 토대로 향후의 새로운 제품에 대해서도 크랙과 같은 문제점을 최소화 할 수 있는 신뢰성 있는 공정 셋업을 제시하기 위해 차원감소법(dimension reduction method)과 근사화 방법인 반응표면법(response surface method), 순차적 근사최적화 기법(Sequential Approximate Optimization, SAO)을 이용하여 신뢰성기반의 강건최적설계를 하였다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.753-758
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• 2004

This study is to suggest a probabilistic design determining configurations of slider air bearings with the dimensional manufacturing tolerances of the ABS. The probabilistic design problem is formulated to minimize the variation in flying height from a target value while satisfying the desired probabilities keeping the pitch and roll angles within suitable range. The proposed approach first solves the deterministic optimization problem. Then, beginning with this solution, the RBDO is continued with the probabilistic constraints affected by the random variables with a fixed standard deviation in normal distribution. The RBDO results are directly compared with the values of the initial design and the results of the deterministic optimization, respectively. The reliability analyses are performed by the descriptive sampling (DS) to show the effectiveness and accuracy of the proposed approach. It is demonstrated that the proposed RBDO approach can efficiently obtain an optimum solution satisfying all the desired probabilistic constraints.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.8
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• pp.695-701
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• 2004

This study is to suggest a Probabilistic design determining configurations of slider air bearings with the dimensional manufacturing tolerances of the ABS. The probabilistic design problem is formulated to minimize the variation in flying height from a target value while satisfying the desired probabilities keeping the pitch and roll angles within a suitable range. The proposed approach first selves the deterministic optimization problem. Then, beginning with this solution, the RBDO is continued with the probabilistic constraints affected by the random variables with a fixed standard deviation in normal distribution. The RBDO results are directly compared with the values of the initial design and the results of the deterministic optimization, respectively. The reliability analyses are performed by the descriptive sampling (DS) to show the effectiveness and accuracy of the proposed approach. It is demonstrated that the Proposed RBDO approach can efficiently obtain an optimum solution satisfying all the desired probabilistic constraints.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.809-812
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• 2008

통신 시스템에 대한 관심은 인터넷의 급격한 발전에 의해 가상공간의 출현과 유비쿼터스 컴퓨팅 환경 구축에 대한 요구가 증대됨에 따라 관련 이론 및 기술의 발전을 주도해 왔다. 이와 관련하여 가장 근간이 되는 문제들 중 하나는 최적 정보 통신 스패닝 트리 (OCST: Optimal Communication Spanning Tree) 설계 문제이다. 본 논문에서는 이러한 OCST 설계 문제를 네트워크 신뢰도를 고려하여 해결하기 위해 유전 알고리즘 (GA)를 이용한다. 본 논문에서는 유전 알고리즘을 이용함에 있어서 n개의 노드들로 구성된 네트워크 문제에서 n-2개의 숫자열로 표현 가능한 유전자 표현법을 이용하고 신뢰성 있는 OCST 설계 문제 해결을 위한 해법으로서 유전 알고리즘을 제안한다. 임의로 생성된 예제에 대한 수치 실험을 통해 통신시스템의 기본 문제 중 하나인 OCST 설계 문제의 해법으로서의 제안 알고리즘의 유용성과 효율성을 확인한다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.6A
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• pp.965-976
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• 2006

A realistic lifetime seismic-reliability based approach is unavoidable to perform Life-Cycle Cost (LCC)-effective optimum design, maintenance, and retrofitting of structures against seismic risk. So far, though a number of researchers have proposed the LCC-based seismic design and retrofitting methodologies, most researchers have only focused on the methodological point. Accordingly, in most works, they have not been quantitatively considered critical factors such as the effects of seismic retrofit, maintenance, and environmental stressors on lifetime seismic reliability assessment of deteriorating structures. Thus, in this study, a systemic lifetime seismic reliability analysis methodology is proposed and a program HPYER-DRAIN2DX-DS is developed to perform the desired lifetime seismic reliability analysis. To demonstrate the applicability of the program, it is applied to an example bridge with or without seismic retrofit and maintenance strategies. From the numerical investigation, it may be positively stated that HYPER-DRAIN2DX-DS can be utilized as a useful numerical tool for LCC-effective optimum seismic design, maintenance, and retrofitting of bridges.

• Computational Structural Engineering
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• v.10 no.4
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• pp.349-358
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• 1997

The present paper describes an investigation into the application of the genetic algorithm (GA) in the optimum design of composite laminated structure. Stochastic processes generate an initial population of designs and then apply principles of natural selection/survival of the fittest to improve the designs. The five test functions are used to verify the robustness and reliability of the GA, and as a numerical example, minimum weight of a cantilever composite laminated beam with a mix of continuous, integer and discrete design variables is obtained by using the GA with exterior penalty function method. The design problem has constraints on strength, displacements, and natural frequencies, and is formulated to a multidimensional nonlinear form. From the results, it is found that the GA search technique is very effective to find the good optimum solution as well as has higher robustness.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.11 no.6
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• pp.44-49
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• 1997

백열전구 시스템의 설계에서 스너버 회로의 설계는 백열전구의 특성을 고려하는 것이 대단히 중요하다. 특히 서지전압 유입시 백열전구의 과도특성은 설계시 보다 많은 설계사양들을 제공하게 된다. 본 논문에서는 서지전압 유입시 과도특성에 근거한 백열전구의 동작모델을 등가회로로 나타냈다. 이 모델은 제조사가 다른 백열전구에도 광범위한 적용이 가능하다. 본 논문에서 제시한 모델이 실질적으로 효용성이 있음을 나타냈으며, 스너버 회로와 리액턴스(LS) 설계시 백열전구의 서지전압 및 과도 특성에 의한 최적설계를 더욱 명확히 할 수 있다.