• 대한조선학회논문집
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• 제40권4호
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• pp.8-15
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• 2003

This paper presents the method for developing an optimum hull form with minimum wave resistance using SQP(sequential quadratic programming) as an optimization technique. The wave resistance is evaluated by a Rankine source panel method with non-linear free surface conditions and the ITTC 1957 friction line is used to predict the frictional resistance coefficient. The geometry of the hull surface is represented and modified using B-spline surface patches. The optimization method is applied to Series 60 hull and KCS(KRISO 3600 TEU Container Ship). The obtained results prove that the method is appropriate for preliminary hull form design.

• 한국생산제조학회지
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• 제9권2호
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• pp.59-65
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• 2000

In this paper the comparison of the first order approximation schemes such as SLP(sequential linear programming) CONLIN(convex linearization) MMA(method of moving asymptotes) and the second order approximation scheme SQP(sequential quadratic programming) was accomplished for optimization of nonlinear structures. It was found that MMA and SQP are the most efficient methods for optimization. But the number of function call of SQP is much more than that of MMA. Therefore when it is considered with the expense of computation MMA is more efficient than SQP. In order to examine the efficiency of MMA for complex optimization problem it was applied to the helicopter tail boom con-sidering column buckling and local wall buckling constraints. it is concluded that MMA can be a very efficient approxima-tion scheme from simple problems to complex problems.

• 한국농공학회지
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• 제37권1호
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• pp.90-99
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• 1995

In this study, the algorithm for the optimum design of cantilever retaining wall was de veloped and solved using Modified Method of Feasible Directions(MMFD), Sequential Linear Programming(SLP) and Sequential Quadratic Programming(SQP). The algorithm was applied to the optimum design of 3-different height cantilever re tairing walls. It was shown that even though the starting points and optimization strategies are dif- ferent, the objective function and optimum design variables converge to within a close range, and consequently the reliability and efficiency of the underlying optimum design algorithm can be verified. It is expected that the optimum design algorithm developed in this study can be utilized efficiently for the optimum design of any scale cantilever retaining wall. Using optimum design method, cantilever retaining wall will be designed more economi- cally and reasonably than using traditional design method.

• International Journal of Naval Architecture and Ocean Engineering
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• 제7권3호
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• pp.478-489
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• 2015

In the present study, a hydrodynamic hull-form optimization algorithm for a container ship was presented in terms of the minimum wave-making resistance. Bell-shaped modification functions were developed to modify the original hull-form and a sequential quadratic programming algorithm was used as an optimizer. The wave-making resistance as an objective function was obtained by the Rankine source panel method in which non-linear free surface conditions and the trim and sinkage of the ship were fully taken into account. Numerical computation was performed to investigate the validity and effectiveness of the proposed hull-form modification algorithm for the container carrier. The computational results were validated by comparing them with the experimental data.

• Composites Research
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• 제13권2호
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• pp.40-50
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• 2000

종횡비가 다른 적층복합재료에 경사형 구조를 도입하고, 이것이 일방향으로의 하중을 받을 때의 좌굴특성을 최대화하기 위해서 복합재료의 각 층에서의 섬유부피분율과 두께를 변수로 sequential linear programming method를 이용하여 최적화 하였다. 이로부터 좌굴특성을 최대화 할 수 있는 최적구조를 제안하였다. 적층복합재료는 종횡비의 영향이 커서 종횡비가 1보다 작은 경우는 최외각층의 섬유부피분율을 최대화하는 방향으로 최적화가 이루어졌으나 종횡비가 2인 경우는 각층에서의 섬유부피분율과 두께비가 어느 정도 균형을 이루는 형태로 최적화가 이루어 졌다. 경사형 구조는 전통적인 균일구조의 복합재료에 비해서 섬유부피와 복합재료의 무게 절감에 큰 효과를 가지는 것으로 확인되었다.

• 한국수자원학회논문집
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• 제35권1호
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• pp.51-64
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• 2002

위험도 평가기준을 발전함수를 고려하여 단일저수지에 적용한 박명기 등(2001)의 혼합정수계획법 모형을 다중저수지군 운영에 적합하도록 개선하였다. 본 모형중의 축차선형계획기법(SLP)은 목적함수중 수력발전함수의 선형화를 위하여 적용되었으며, 저수지 방류량의 합리적인 월별 방류배분을 위하여 수력발전량에 대한 가중치를 발전시간 수준별로 적용하도록 정식화요소에 반영하였다. 개선된 모형은 한강수계 5개 저수지군에 시험적용 하였으며, 수계내 연계운영을 위한 복합저수지군의 최적연계에 본 위험도 평가기준을 적용할수 있음을 확인할 수 있었다.

• Journal of Mechanical Science and Technology
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• 제17권1호
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• pp.40-47
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• 2003

In this paper, we constructed the analytic model of control valve as a function of electric and geometric parameters, and analyzed the influence of the design parameters on the dynamic characteristics. For improving the dynamic characteristics, optimal design is conducted by applying sequential quadratic programming method to the analytic model. This optimal design aims to minimize the response time and maximize force efficiency. By this procedure, control valve can be designed to have fast response in motion.

• 한국농공학회지
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• 제36권2호
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• pp.111-122
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• 1994

In this study, an algorithm which can be applied to the optimum design of simple steel plate girders was developed, and efficient optimization strategies for the solution of algorithm were found out. The optimum design algorithm consists of 3-levels of optimization. In the first and second levels of optimization, the absolute maximum bending moment and shearing force are extracted and in the third level of optimization, the optimum cross section of steel plate girder is determined. For the optimum design of cross section, the objective function is formulated as the total area of cross section and constraints are derived in consideration of the various stresses and the minimum dimension of flange and web based on the part of steel bridge in the Korea standard code of road bridge. Sequential unconstrained minimization technique using the exterior penalty function method(SUMT-EP), sequential linear programming(SLP) and sequential quadratic programming (SQP) are proved to be efficient and robust strategies for the optimum design of simple plate girder cross section. From the reliable point of view, SLP is the most efficient and robust strategy and SQP is the most efficient one from the viewpoint of converguency and computing time.

• 한국공간구조학회:학술대회논문집
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• 한국공간구조학회 2008년도 춘계 학술발표회 논문집
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• pp.101-106
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• 2008

본 연구에서는 서로 상이한 최적화기법인 유전알고리듬과 수학적 프로그래밍기법을 이용하여 지오데식 돔 구조물을 최적화하고 그 결과를 분석하였다. 본 연구에서 도입한 유전알고리즘은 유전연산자인 선택, 교배, 돌연변이 이외에도 재생기법을 도입하여 최적해의 검색성능을 높였다. 그리고 수학적인 프로그래밍기법은 유한차분법을 이용하여 목적함수의 설계민감도를 계산하였으며 세 가지의 다른 검색기법을 이용하여 돔의 크기최적화를 수행하였다. 지오데식 돔의 중앙에 작용하는 집중하중에 저항하는 돔의 각 부재의 크기패턴을 자체 개발된 $ISADO-GA{\alpha}$와 ISADO-OPT를 이용하여 최적 설계하였다. 본 연구를 통하여 제시된 최적결과는 정해가 존재하지 않는 실제 구조물의 최적 값에 대한 유용한 정보를 제공할 뿐만이 아니라 향후 대공간구조의 새로운 구조시스템 개발의 밑거름이 될 것으로 판단된다.

• 산업공학
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• 제11권1호
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• pp.183-190
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• 1998

This paper is concerned with the bicriteria vehicle routing problems with time window constraints(BVRPTW). The BVRPTW is to determine the most favorable vehicle routes that minimize the total vehicle travel time and the total customer wait time which are, more often than not, conflicting. We construct a linear goal programming (GP) model for the BVRPTW and propose a heuristic algorithm to relieve a computational burden inherent to the application of the GP model. The heuristic algorithm consists of a parallel insertion method for clustering and a sequential linear goal programming procedure for routing. The results of computational experiments showed that the proposed algorithm finds successfully more favorable solutions than the Potvin an Rousseau's method that is known as a very good heuristic for the VRPs with time window constraints, through the change of target values and the decision maker's goal priority structure.