• Proceedings of the Korean Operations and Management Science Society Conference
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• 2006.11a
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• pp.161-164
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• 2006

The sales of consumer durables are composed of first time purchases and replacement purchases. Since the sales for most mature durable products are dominated by replacement sales, it is necessary to develop a model incorporating replacement component of sales in order to forecast total sales accurately. Several single product diffusion models incorporating replacement demand have been developed, but research addressing the multi-product diffusion models has not considered replacement sales. In this paper, we propose a model based on consumer choice behavior that simultaneously captures the diffusion and the replacement process for multi-product relationships. The proposed model enables the division of replacement sales into repurchase by previous users and transition purchase by users of different products. As a result, the model allows the partitioning of the total sales according to the customer groups (first-time buyers, repurchase buyers, and transition buyers), which allows companies to develop their production and marketing plans based on their customer mix. We apply the proposed model to the Korean automobile market, and compare the fitting and forecasting performance with other Bass-type multi-product models.

• Journal of the military operations research society of Korea
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• v.3 no.1
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• pp.97-107
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• 1977

This report examines several models, such as random or area bombardment, salvo fire and pattern fire, for the computation of target coverage when multiple rounds are fired at a target. Fractional kill of a fragment sensitive target by a fragmenting projectile as a function of the number of rounds fired is compared for two salvo fire models. The first is a standard salvo fire model in which N rounds are fired at the same aim point, in the second model single kill probability is computed for a fragment sensitive target and then fractional kill from the firing of N rounds is computed according to the assumption that the effects of each round are independent. Because the method of solution becomes very laborious for large patterns, this report gives a method only for the case of evaluating the effectiveness of stick and trianglar pattern fire. The need for the sophisticated and complicated target coverage models is demonstrated by the results of computations performed in this report.

• Journal of the military operations research society of Korea
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• v.26 no.2
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• pp.75-89
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• 2000

This paper deals with complex system theory to describe guerrilla warfare situation using EINSTein (Enhanced ISAAC Neural Simulation Tool) simulation model. EINSTein model is an agent-based artificial "laboratory" for exploring self-organized emergent behavior in land combat. Many studies have shown that existing Lanchester equations used in most guerrilla warfare models do not describe changes of combat units, real guerrilla warfare situation and qualitative factors in combat. Future warfare will be information warfare with various weapon system and complex combat units. We have compared and tested results with Lanchester models and EINSTein model. And the EINSTein model has been applied and analyzed to guerrilla warfare model (C4I facilities, coastal, urbanized terrain critical facilities defense). The results show that the EINSTein model has a possibility to apply and analyze guerrilla warfare more properly than Lanchester models.

• Journal of the Korean Operations Research and Management Science Society
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• v.31 no.2
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• pp.113-127
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• 2006

We consider an integrated supply chain model in which multiple suppliers replenish items for a single buyer's demand. Also the buyer specifies a basic replenishment cycle and the suppliers replenish the items only at those time intervals. Namely, we propose a model to study and analyze the benefit by coordinating supply chain inventories through the basic replenishment cycle time. The objective of this model is to minimize the total relevant annual cost of the integrated inventory model. After developing proposed coordinated models, we suggest heuristics for searching the solutions of our models. Finally, numerical and computational experiments for each policy are carried out to evaluate the benefits of those models and the compensation policy is addressed to share the benefits.

• 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.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2008.10a
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• pp.262-262
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• 2008

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1996.04a
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• pp.120-120
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• 1996

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2000.04a
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• pp.284-284
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• 2000

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2000.04a
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• pp.235-238
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• 2000

This article presents an adaptive decision tree algorithm for dynamically reasoning machine failure cause out of real-time, large-scale machine status database. On the basis of experiment using semiconductor etching machine, it has been verified that our model outperforms previously proposed decision tree models.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1992.04b
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• pp.180-186
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• 1992

A system is considered which is required to perform several tasks which arrive randomly during the fixed mission duration.