• Proceedings of the Korean Operations and Management Science Society Conference
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• 1993.04a
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• pp.109-118
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• 1993

This paper describes the management of knowledge base and optimization models using knowledge-assisted optimization model formulation system UNIK-OPT (UNIfied Knowledge-OPTimization). We will illustrate UNIK-OPT with the case of production scheduling in refinery.

• Korean Management Science Review
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• v.13 no.3
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• pp.1-21
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• 1996

This study aims to systematize the needs of each area for computerized production management of small- and medium-sized firms and establish the basic design background of their common database. For this purpose, we surveyed the status, needs and appliable characteristics of the firms production system by the categories of industry, size and production type. On the base of these surveys the basic design concept and contents of automatic production system for small and medium-sized firms are proposed.

• Journal of the Korean Operations Research and Management Science Society
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• v.28 no.2
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• pp.1-15
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• 2003

This paper presents a new evolutionary algorithm to solve complex multi-level integration problems, which is called multi-level symbiotic evolutionary algorithm (MEA). The MEA uses an efficient feedback mechanism to flow evolution information between and within levels, to enhance parallel search capability, and to improve convergence speed and population diversity. To show the MEA's applicability, It is applied to the integrated planning of production and distribution in supply chain management. The encoding and decoding methods are devised for the integrated problem. A set of experiments has been carried out, and the results are reported. The superiority of the algorithm's performance is demonstrated through experiments.

• Journal of the Korean Operations Research and Management Science Society
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• v.21 no.3
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• pp.143-157
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• 1996

This paper addresses the effects of an imperfect production process on the optimal production quantity and quality inspection policies. The system is assumed to deteriorate during the production process. The result are either the production of a number of defective items or the breakdown of the production meachine. A simple rule has been suggested to determine whether multiple quality in spection is workth or not. Furthermore, when multiple inspection policy is adopted, the optimal in spection schedule is shown to be equally spaced throughout the production cycle. Exact solution and approximation of the optimal production quantity and approximation of the optimal number of inspection are provided. Finally , to better understand the model of this paper, comparisons between this model and classical EMQ model are provided.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2002.05a
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• pp.476-480
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• 2002

The theory of constraints (TOC) has become a valuable system in modern operations management. Using the ideas and methods of the TOC, companies can achieve a large reduction of work-in-process and finished-goods inventories, significant improvement in scheduling performance, and substantial earnings increase. The purpose of this paper is to calculate the optimal size of the time buffer which is used to accommodate disruptions in production processes and provide maximum productivity of capacity constrained resources. After the problem formulation in terms of single server queueing model, we observed the system behavior by sensitivity analyses.

• Journal of the Korean Operations Research and Management Science Society
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• v.34 no.4
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• pp.139-151
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• 2009

Based on single-vendor single-buyer integrated production-inventory problem, a model considering freight costs discounts is suggested when the cargo capacity is constrained. With the cost function formulated, several properties of the model are derived and analyzed. An efficient algorithm to find solutions such as shipment lot size, number of shipments and number of full truckloads using properties derived is suggested. Numerical results are provided to illustrate the proposed solution procedures and to provide additional insights.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1995.04a
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• pp.99-99
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• 1995

• Journal of the Korean Operations Research and Management Science Society
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• v.18 no.1
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• pp.1-18
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• 1993

The family disaggregation model of hierarchical production planning (HPP) is the problem of (0 -1) mixed integer programming that minimizes the total sum of setup costs and inventory holding costs over the planning horizon. This problem is hard in a practical sense since optimal solution algorithms have failed to solve it within reasonable computation times. Thus effective familoy disaggregation algorithm should be developed for HPP. The family disaggregation algorithm developed in this paper consists of the first stage of finding initial solutions and the second stage of improving initial solutions. Some experimental results are given to verify the effectiveness of developed disaggregation algorithm.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1995.04a
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• pp.122-129
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• 1995

This paper presents a similarity coefficient based approach to the problem of machine-part grouping for cellular manufacturing. The method uses relevant production data such as part type, production volume, routing sequence to make machine cells and part families for cell formation. A new similarity coefficient using weighted factors is introduced and an algorithm for formation of machine cells and part families is developed. A comparative study of two similarity coefficients - Gupta and seifoddini's method and proposed method - is conducted. A software program using TURBO C has been developed to verify the implementation.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2006.05a
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• pp.133-136
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• 2006

We consider dynamic lot-sizing model with production time windows where each of n demands has earliest due date and latest due date and it must be satisfied during the given time window. For the case of nonspeculative cost structure, an O(nlog n) time procedure is developed and it is shown to run in O(n) when demands come in the order of latest due dates.