• 한국경영과학회지
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• 제33권2호
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• pp.137-151
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• 2008

This paper deals with two shops dealing with single perishable product the fresh items are sold at a list price in the primary shop and the unsold items that have reached a certain allowed age are transferred to the secondary shop to be sold at a discounted price. It is assumed that the demand rates in two shops are Independent each other and can be expressed as a function of inventory level and price. With the objective of maximizing the profit under a Last-In-first-Out. (LIFO) issuing policy, we develop mathematical models for the following two cases : (1) opening primary shop only and (2) opening both primary shop and secondary shop. There are three decision variables, i.e., the reduced price in the secondary shop, the allowed age at the primary shop, and the order quantities at the primary shop. A solution procedure is developed based on tabu search and its validity is illustrated through a comparative study.

• 품질경영학회지
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• 제27권3호
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• pp.142-153
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• 1999

In the context of total quality management, customer satisfaction is a key factor of success. Customer needs have been in the past described with rather vague words. In order to lead in the competitive market, product designers must be willing to interpret and reflect customer perceptions of a product on the design. The objective of this research is to develop a systematic process capable of linking customer preferences on a product to the design of product elements or specifications. The design process consists of multivariate statistical analyses, semantic differentials, and multidimensional scaling techniques under the framework of a methodology known as quality function deployment which is frequently used to construct a quality design process. The process being established is expected to serve as an effective means to communicate between the customer and the designer through proper representational schemes of design elements.

• 품질경영학회지
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• 제5권1호
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• pp.23-29
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• 1977

Geometric programming is very useful for the solution of certain nonlinear programming problems in which the objective function and the constraints are posynomial expressions. By solving the dual program, it can be obtained that the solution of the primal program of Geometric programming. And, more efficient solution is to form an Augmented program possessing degree of difficult zero. A regional water-quality management problem may involve a multistage constrained optimization with many decision variables. In this problem, especially, appling that solution to it is also useful. This paper is described that : 1) the efficient solution of a water-quality management model formed by Geometric programming and 2) the algorithm developed to apply easily a real system by modifing and simplifing the solution.

• International Journal of Aeronautical and Space Sciences
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• 제17권4호
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• pp.491-500
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• 2016

This paper presents a highly efficient aeroelastic optimization method based on a surrogate model; the model is verified by considering the case of a high-aspect-ratio composite wing. Optimization frameworks using the Kriging model and genetic algorithm (GA), the Kriging model and improved particle swarm optimization (IPSO), and the back propagation neural network model (BP) and IPSO are presented. The feasibility of the method is verified, as the model can improve the optimization efficiency while also satisfying the engineering requirements. Moreover, the effects of the number of design variables and number of constraints on the optimization efficiency and objective function are analysed in detail. The accuracy of two surrogate models in aeroelastic optimization is also compared. The Kriging model is constructed more conveniently, and its predictive accuracy of the aeroelastic responses also satisfies the engineering requirements. According to the case of a high-aspect-ratio composite wing, the GA is better at global optimization.

• 한국전산유체공학회지
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• 제10권1호
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• pp.16-23
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• 2005

The objective of this research is to estimate two dimensional ablating and charring of heat shield materials in severe aero-thermal heat transfer. This estimation requires an accurate and rapid technique for its serious heat transfer with a moving boundary. Aerodynamic heating is obtained by an explicit relation which is a function of Mach number and air condition, while a fully implicit method is used for heat transfer calculations. Moving boundary is captured by FLIAR method which is a subgroup of VOF. Thickness of ablating and charring of heat shield, temperature of the moving surface and rate of radiation heat are calculated and compared with references. The results are in good agreement with other calculations.

• 대한토목학회논문집
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• 제12권1호
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• pp.197-205
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• 1992

혼성방파제단면의 최적설계를 위해, ALM-BFGS 조합알고리즘을 이용한 컴퓨터 프로그램 PROCOBRA가 개발되었다. 혼성방파제의 단면최적화를 위한 정식화의 모형이 제시되었으며 단면의 부분별 가중치가 목적함수에 도입되었다 수치예를 통하여 프로그램의 유용성이 입증되었다. 연구결과 ALM-BFGS 알고리즘이 해안구조물의 최적설계에 효율적으로 적용될 수 있으며, 경제적인 혼성방파제 설계가 가능함을 알 수 있었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 B
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• pp.567-569
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• 1992

Design sensitivity analysis is proposed for the optimal shape design of three dimensional magnetostatic problems. The direct differentiation method is introduced for design sensitivity analysis and the boundary element method with reduced magnetic scalar potential as the state variable is used to analyze the magnetic characteristics. In the direct differentiation method, the design sensitivity, defined as the total derivative of the objective function with respect to the design variables, is calculated based on the variation of the state variable with respect to the design variable. And the variation of He state variable is calculated by differentiating the both sides of the system matrix equation obtained by applying boundary element method. Through the numerical example with simple electromagnet, the usefullness is proved.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.482_483
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• 2009

This paper presents a method of finding the optimal operating point minimizing a given objective function with 3 phase power flow equations and operational constraints, called 3 phase optimal power flow. 3 phase optimal power flow can provide operation and control strategies for the distribution systems with distributed generation assets, which might be frequently in unbalanced conditions assuming that high penetration rate of renewable energy sources in the systems. As the solution technique, this paper adopts a standard particle swarm optimization (PSO).

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.658_659
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• 2009

This paper deals with the numerical implementation of the material sensitivity analysis, which is used to efficiently determine an optimal electric current distribution on a ship hull by corrosion of ship. A material sensitivity formula for the forward problem formulated in terms of the equivalent current method is analytically derived. Then, the components of the adjoint system including the electric pseudo-source are thoroughly investigated in order to obtain the first-order gradient information of an objective function with respect to the electric current. The purposed method has been successfully applied to a model ship and the predicted result on the underwater electric field due to corrosion of ship have been compared to that computed by FNREMUS software.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.159_160
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• 2009

In this paper proposes a new algorithm of efficiency outage restoration using a outage load switching to a healthy MTR a fault occurrence at a MTR. In addtion, proposed algorithm includes a outage restoration method which keeps MTR optimal capacity with reorganization of distribution network in case it can not restore outage state loads caused by shortage of healthy MTR remain capacity. In case that proposed sequence still can not complete restoration, this paper suggests a efficiency outage restoration with objective function included priority in outage loads.