• Journal of Korean Institute of Industrial Engineers
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• v.38 no.2
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• pp.74-79
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• 2012

An efficient separation heuristic for the rank-1 Chvatal-Gomory cuts for the binary knapsack problem is proposed. The proposed heuristic is based on the decomposition property of the separation problem for the fixedcharge 0-1 knapsack problem characterized by Park and Lee [14]. Computational tests on the benchmark instances of the generalized assignment problem show that the proposed heuristic procedure can generate strong rank-1 C-G cuts more efficiently than the exact rank-1 C-G cut separation and the exact knapsack facet generation.

• The Journal of Fisheries Business Administration
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• v.37 no.2 s.71
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• pp.19-32
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• 2006

The sea environment must be preserved for maintaining various coastal resources. In order to preserve the sea environment, this study is to find problems in the process of producing photocatalyst materials, which can purify sea pollution, and to develop the heuristic algorithm satisfying those problems. The heuristic algorithm of this paper is developed through constructing the mathematical model and analyzing the mathematical structure of variables and constraints in that model. The algorithm developed in this paper consists of the first process of initializing, the second process of lot combination and the third process of improving solutions. Some experimental results are given to verify the effectiveness of the heuristic algorithm developed in this paper.

• Journal of the Korea Society of Computer and Information
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• v.22 no.9
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• pp.81-89
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• 2017

The CRP(Container Relocation Problem) algorithms pursuing efficient container relocation of wharf container terminal can not be deterministic because of the large number of layout cases. Therefore, the CRP algorithms should adopt trial and error intuition and experimental heuristic techniques. And because the heuristic can not be best for all individual cases, it is necessary to find metrics which show excellent on average. In this study, we analyze GLAH(Greedy Look-ahead Heuristic) algorithm which is one of the recent researches in detail, and propose a heuristic metrics HOB(sum of the height differences between a badly placed container and the containers prohibited by the badly placed container) to improve the algorithm. The experimental results show that the improved algorithm, GLAH', exerts a stable performance increment of up to 3.8% in our test data, and as the layout size grows, the performance increment gap increases.

• IE interfaces
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• v.12 no.4
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• pp.617-624
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• 1999

In order to maximize an availability of machine and utilization of space, the parallel machines scheduling problem with space limit is frequently discussed in the industrial field. In this paper, we consider a scheduling problem for assembly machine in ship engine assembly shop. This paper considers the parallel machine scheduling problem in which n jobs having different release times, due dates and space limits are to be scheduled on m parallel machines. The objective function is to minimize the sum of earliness and tardiness. To solve this problem, a heuristic is developed. The proposed heuristic is divided into three modules hierarchically: job selection, machine selection and job sequencing, solution improvement. To illustrate its effectiveness, a proposed heuristic is evaluated with a large number of randomly generated test problems based on the field situation. Through the computational experiment, we determine the job selection rule that is suitable to the problem situation considered in this paper and show the effectiveness of our heuristic.

• Journal of the Korean Operations Research and Management Science Society
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• v.21 no.3
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• pp.75-88
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• 1996

This paper presents an efficient heuristic technique for minimizing the objectives related to tardiness such as total tardiness, maximum tardiness and root mean of tardiness in the job shop scheduling. The heuristic technique iteratively improves an active schedule through exploring the schedule's neighborrhood, using operation move methods. The move operatio is defined on an active chain of tardy jobs in the active schedule. To find the move operations which have a high probability of reducing tardiness, we develop move methods by exploiting the properties of active chains. Our technique is compared with the two existing heuristic techniques, that is, MEHA(Modified Exchange Heuristic Algorithm) and GSP(Global Scheduling Procedure) under the various environmental with the three levels of due date tightness and several sized problems. The experimental results show that the proposed technique outperforms the two exissting techiques in terms of solution quality and computation time.

• Journal of the Korean Operations Research and Management Science Society
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• v.39 no.4
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• pp.97-113
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• 2014

Circular shareholding refers to a situation where at least three member firms in a business group have stock in other member firms and establish a series of ownership in a circular way. Although many studies have focused on the ultimate effect of circular shareholding on firm's value and profitability, there have been few studies which address how to resolve circular shareholding from the perspective of optimization theory. This paper proposes a heuristic method for identifying shareholdings which need to be cleared in order to settle the problem of circular shareholding in a business group. The proposed heuristic tries to maximize the sum of voting rights the controlling family has in its business group firms. The applications results confirm that the heuristic provides near-optimal solutions for most of 16 Korean large business groups involving circular shareholding.

• The Journal of Information Systems
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• v.28 no.4
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• pp.175-197
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• 2019

Purpose This study develops a heuristic algorithm to solve the time-resource tradeoffs in project scheduling problems with a real basis. Design/methodology/approach Resource constrained project scheduling problem with time-resource tradeoff is well-known as one of the NP-hard problems. Previous researchers have proposed heuristic that minimize Makespan of project scheduling by deriving optimal combinations from finite combinations of time and resource. We studied to solve project scheduling problems by deriving optimal values from infinite combinations. Findings We developed heuristic algorithm named Push Algorithm that derives optimal combinations from infinite combinations of time and resources. Developed heuristic algorithm based on simulated annealing shows better improved results than genetic algorithm and further research suggestion was discussed as a project scheduling problem with multiple resources of real numbers.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.1 no.1
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• pp.6-12
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• 2001

Evolutionary algorithms(EAs) have been successfully applied to many combinatorial optimization problems of various engineering fields. Recently, some comparative studies of EAs with other stochastic search algorithms have, however, shown that they are similar to, or even are not comparable to other heuristic search. In this paper, a new hybrid evolutionary algorithm utilizing a new local heuristic search, for combinatorial optimization problems, is presented. The new intelligent local heuristic search is described, and the behavior of the hybrid search algorithm is investigated on two well-known problems: traveling salesman problems (TSPs), and quadratic assignment problems(QAPs). The results indicate that the proposed hybrid is able to produce solutions of high quality compared with some of evolutionary and simulated annealing.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2006.05a
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• pp.1740-1745
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• 2006

This paper is concerned with a novel heuristic algorithm for the multi-trip vehicle routing problem with time windows. The objective function is the minimization of total vehicle operating time, fixed cost of vehicle and the minimization of total lateness of customer. A mixed integer programming formulation and a heuristic algorithm for a practical use are suggested. A heuristic algorithm is constructed two phases such as clustering and routing. Clustering is progressed in order to assign appropriate vehicle to customer, and then vehicle trip and route are decided considering traveling distance and time window. It is shown that the suggested heuristic algorithm gives good solutions within a short computation time by experimental result.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2006.05a
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• pp.1733-1739
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• 2006

This paper is concerned with multi-objective vehicle routing problem(VRP), in which objective of this problem is to minimize the total operating time of vehicles and the total tardiness of customers. A mixed integer programming formulation and a heuristic for practical use are suggested. The heuristic is based on the route-perturbation and route-improvement method(RPRI). Performances are compared with other heuristic appeared in the previous literature using the modified bench-mark data set. It is shown that the suggested heuristic give good solution within a short computation time by computational experiment.