• 품질경영학회지
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• 제16권1호
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• pp.32-42
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• 1988

The general n/m job-shop problem is easy to state what is required, but it is extremely difficult to make any progress whatever toward a solution. This paper was first to examine a heuristic procedure of general n/m scheduling generation focused on the procedure of MWRK (Most Work Remaining) presented by Giffler and Thompson (1960) among others. Then modified procedure was proposed to obtain better solution in light of the key measure of performance compared with that of the literature presented by Baker (1974). The modified procedure then has been extended to other example problem to test the better results and to assure the properness of application.

• Management Science and Financial Engineering
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• 제12권1호
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• pp.127-142
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• 2006

In this paper, we present a frequency reassignment problem (FRP) that arises when we add new base stations to resolve hot-spots or to expand the coverage of a code division multiple access (CDMA) network. For this problem, we develop an integer programming (IP) model along with some valid inequalities and preprocessing rules. Also, we develop an effective heuristic procedure that solves two sub-problems induced from the original problem in repetition. Computational results show that the proposed heuristic procedure finds a feasible solution of good quality within reasonable computation time. Also, the lower bound by-produced from the heuristic procedure is quite strong.

• 대한산업공학회지
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• 제5권1호
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• pp.45-51
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• 1979

This paper presents a heuristic solution procedure for the quadratic assignment problem, ranking procedure, which can handle the case where not all of the facilities have the same size of area. The ranking procedure is found more efficient than two other existing heuristic procedures from results of computational experience. Based on the out-patients flow pattern and the procedure developed, an improved layout of the three existing general hospitals is developed with the objective of minimizing the total distance travelled by patients in the central and the out-patient clinic.

• 한국경영과학회지
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• 제19권1호
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• pp.69-83
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• 1994

This paper deals with a capacitated ring-star network design problem (CRSNDP) with node capacity constraints. The CRSNDP is formulated as a mixed 0-1 integer problem, and a 2-phase heuristic solution procedure, ADD & VAM and RING, is developed, in which the CRSNDP is decomposed into two subproblems : the capacitated facility location problem (CFLP) and the traveling sales man problem (TSP). To solve the CFLP in phase I the ADD & VAM procedure selects hub nodes and their appropriate capacity from a candidate set and then assigns them user nodes under node capacity constraints. In phase II the RING procedure solves the TSP to interconnect the selected hubs to form a ring. Finally a solution of the CRSNDP can be achieved through combining two solution of phase I & II, thus a final design of the capacitated ring-star network is determined. The analysis of computational results on various random problems has shown that the 2-phase heuristic procedure produces a solution very fast even with large-scale problems.

• 산업경영시스템학회지
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• 제33권3호
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• pp.199-207
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• 2010

In this paper considered is the provisioning quantity determination problem of consumable concurrent spare parts (CSP) of a new equipment system to minimize the procurement cost under the operational availability constraint. When a part fails, repair of the failed part is impossible and the part is replaced and cannibalization is allowed. The failure of a part is assumed to follow a Poisson process and the operational availability in CSP is defined. The solution procedure consists of two parts. Firstly, a heuristic algorithm is developed under the assumption that the failure rate is constant during the CSP period. Secondly, proposed is a simulation search procedure which improves the heuristic solution to the near optimal solution in a reasonable amount of time. An illustrative example is shown to explain the solution procedure.

• 산업경영시스템학회지
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• 제20권44호
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• pp.179-184
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• 1997

A solution procedure to minimize total carousel related costs has been developed under the carousel throughput rate and total storage capacity requirements. The carousel related costs include carousel facility costs which are proportional to the number of carousels and carousel operating costs which are directly related to the moving distances of carousels. The number of carousels is dependent upon the size of a carousel and the moving distances are determined by the size of a carousel, storage item assignment to each carousel, and the item positions in a carousel. When the storage/retrieval requirements for each storage item is equal, an optimal algorithm has been developed. When the storage/retrieval requirements is unequal, a heuristic solution procedure has been developed because of the complexity of the problem.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 2003년도 추계학술대회 및 정기총회
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• pp.81-84
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• 2003

The ability to determine the optimal frequencies and offsets for independent and unrestricted ordering cycles for multiple items can be very valuable for managing storage capacity constrained facilities in a supply chain. The complexity of this problem has resulted in researchers focusing on more tractable surrogate problems that are special cases of the base problem. Murthy et al. (European Journal of Operation Research 2003) developed insights leading to solution of the original problem and present a heuristic for offsetting independent and unrestricted ordering cycles for items to minimize their joint storage requirements. However, their study cannot find optimal solution due to the Greedy Heuristic solution procedure. In this paper, we present a complete procedure to find the optimal solution for the model with a integer programming optimization approach and genetic algorithm. Numerical examples are included to compare each model with that of Murthy et at. Research of this type may prove useful in solving the more general problem of selecting order policies to minimize combined holding, ordering, and storage costs.

• 한국경영과학회지
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• 제18권1호
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• pp.29-43
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• 1993

This paper condisers a problem of determining arc capacities for a communication network with fixed-charged linear arc-cost functions, which is known to be NP-hard. For the problem, an efficient heuristic solution procedure is derived. The procedure is further shown working well for designing arc capacities of a network in a situation where the network needs to be extended by connecting its nodes to some new nodes or where the network needs to be extended by expanding its arc capacities.

• 산업경영시스템학회지
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• 제14권23호
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• pp.27-36
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• 1991

This paper considers scheduling a set of n-jobs on m-paraller identical processors in which all jobs have the common due date. The objective of the problem is to minimize the weighted mean absolute deviation of job completion times about such common due dates under the assumption that each job has a different weight. and to determine the optimal value of a common due date. We propose four heuristic solution methods based on several dominance conditions, and its solution procedure is illustrated with numerical examples. The Performance comparison is made among four heuristic scheduling procedures.

• 한국산학기술학회논문지
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• 제11권5호
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• pp.1716-1729
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• 2010

본 논문에서는 링과 메쉬 구조를 이용한 경제적인 계층형 광통신망 설계 문제를 다룬다. 계층형(hierarchical) 광통신망 설계 문제에서 고려하는 비용 요소는 링 구조의 광통신망 내부(intra-ring) 트래픽 처리를 담당하는 OADM(Optical Add-Drop Multiplexer), 메쉬 구조의 링간(inter-ring) 트래픽 처리를 담당하는 OXC(Optical Cross-Connect) 및 OADM간 케이블 비용 및 OXC간 케이블 비용이다. 이 논문에서 제시하는 계층형 광통신망 설계 문제에서는 OADM 및 OXC의 트래픽 처리 용량과 각 링의 OADM 개수 제약을 고려한다. 이 논문에서는 계층형 광통신망 설계 문제를 정수계획법(integer programming) 모형으로 모델링하며, 링의 대칭성(symmetry)을 부분적으로 제거하는 절단평면(cutting planes)을 개발한다. 또한, 우수한 품질의 해를 적절한 시간동안 찾기 위해 휴리스틱 알고리즘을 개발한다. 모의 실험을 통해 절단평면과 휴리스틱 알고리즘의 성능을 평가한 결과 크기가 작은 문제에 대해서는 이 논문에서 개발한 절단평면을 정수계획법 모형에 추가함으로서 최적해를 구하는 시간을 크게 단축시키며, 크기가 큰 문제에 대해서는 이 논문에서 개발한 휴리스틱 알고리즘이 상용 소프트웨어인 CPLEX가 찾는 휴리스틱 해보다 우수한 해를 발견함을 확인하였다.