• Management Science and Financial Engineering
• /
• v.12 no.1
• /
• pp.95-112
• /
• 2006

Disassembly scheduling is the problem of determining the quantity and timing of disassembling used or end-of-life products while satisfying the demand of their parts and/or components over a planning horizon. The case of assembly product structure is considered while the resource capacity constraints are explicitly considered. A cost-based objective is considered that minimizes the sum of disassembly operation and inventory holding costs. The problem is formulated as an integer programming model, and a two-stage heuristic with construction and improvement algorithms is suggested in this paper. To test the performance of the heuristic, computational experiments are done on randomly generated problems, and the results show that the heuristic gives near optimal solutions within a very short amount of computation time.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 2005.05a
• /
• pp.715-722
• /
• 2005

Disassembly scheduling is the problem of determining the quantity and timing of disassembling used products while satisfying the demand of their parts or components over a planning horizon. The case of single product type with assembly structure is considered for the objective of minimizing the sum of disassembly operation and inventory holding costs. In particular, the resource capacity constraint is explicitly considered. The problem is formulated as an integer programming model, and a two-stage heuristic with construction and improvement algorithms is suggested in this paper. To show the performance of the heuristic, computational experiments are done on a number of randomly generated problems, and the test results show that the algorithm can give near optimal solutions within a very short amount of computation time.

• Asia-Pacific Journal of Business
• /
• v.13 no.3
• /
• pp.281-291
• /
• 2022

Purpose - We study whether the bullwhip effect is prevalent among Korean firms and how the characteristics of it differ from the ones in other countries. Design/methodology/approach - We obtained quarterly financial and operational information on KOSPI-listed firms in manufacturing, wholesale, and retail industries from 2013 to 2019. We explore the variation of the bullwhip effect across firms and validate hypotheses. Findings - First, we find that for the KOSPI-listed firms, the bullwhip effect is more prevalent compared with the production smoothing. We provide additional findings by using sub-samples of manufacturing firms, wholesaling and retailing firms, big-sized firms, small- and medium-sized firms, domestic-sales intensive firms, and export intensive firms. Second, we show that in general, the bullwhip effect of Korean firms increases with the days in inventory or the demand seasonality ratio. However, the persistence of demand shock does not affect the bullwhip effect of Korean firms. Research implications or Originality - We compare our results with those in other studies that use information on the U.S. and Chinese firms. Our findings show that factors explaining the bullwhip effect across Korean firms have similarities and differences compared with firms in the U.S. and Chinese firms.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 2000.04a
• /
• pp.61-64
• /
• 2000

This paper analyzes a dynamic lot-sizing problem, in which the order size of multiple products and a single container type are simultaneously considered. In the problem, each order (product) placed in a period is immediately shipped immediately by containers in the period and the total freight cost is proportional to the number of each container type employed. Also, it is assumed that backlogging is not allowed. The objective of this study is to determine the lot-sizes and the shipping policy that minimizes the total costs, which consist of ordering costs, inventory holding costs, and freight costs. Because this problem is NP-hard, we propose a heuristic algorithm with an adjustment mechanism, based on the optimal solution properties. The computational results from a set of simulation experiment are also presented.

• Management Science and Financial Engineering
• /
• v.1 no.1
• /
• pp.39-66
• /
• 1995

This article presents a new model called the periodic square wave(PSW) to describe the material flow of periodic processes involving an intermediate buffer. The material flows into and out of the intermediate buffer are assumed to be periodic square shaped. By using this model, It is proved that the classical economic lot size model with finite supply rate, the so-called EPQ model, can be applicable to the arbitrary periodic demand case. This new model relaxes the original assumption of the constant demand. It is shown, as a unique application example, that the explicit solution for determining both upstream and downstream economic lot size can be obtained with the aid of the PSW model. The PSW model provides more accurate information on analyzing the inventory and production system than the classical approach, without losing simplicity and increasing the computational burden.

• Journal of the Korea Safety Management & Science
• /
• v.16 no.3
• /
• pp.327-333
• /
• 2014

Changes in the business environment in which intense and sustained growth and survival must meet a variety of customer needs (Q, C, D) and business side of the enterprise for profit structure reformation is absolutely necessary for innovation activities. So far, management of innovation in method BPR, PI, OVA, 6 Sigma, Strategic Purchasing, PPM, SCM etc. are being introduced. However, they have a limit of partial optimization and improvement-oriented techniques. So this paper studied the TPI(Total Profit Innovation) application in order to derive empirical methodology to maximize profitability for the domestic S foundry factory. To this end, long-term gains through structural analysis and intensity analysis to ensure continued growth and profitability strategy are devised through management Innovation analysis. And improvement projects was presented to solve main issues of five categories(Inventory, Sales Mix, Cost, Quality Cost, Skill and Work-load) We will expect the office productivity improvement and financial performance improvement and then continually accumulate and review the results.

• Journal of Korean Institute of Industrial Engineers
• /
• v.40 no.3
• /
• pp.291-298
• /
• 2014

Demand forecasting plays a key role in overall business activities such as production planning, distribution management, and inventory management. Especially, for a fast-changing environment of the clothing industry, logical forecasting techniques are required. In this study, we propose a procedure to predict product life cycle using data mining algorithms. The proposed procedure involves three steps : extracting key variables from profiles, clustering, and classification. The effectiveness and applicability of the proposed procedure were demonstrated through a real data from a leading clothing company in Korea.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.7 no.2
• /
• pp.238-245
• /
• 2006

This study presents a design of integrated management system for manufacturing company for the purpose of reducing operation cost and speeding up flow of processes. Since common commercial management package should be well customized to reflect inherent processes of each company with great deal of effort, this study chooses a manufacturing company that produces component parts of automobile as a target company and designs management system specified for that target company. System design focuses on the minimization of the indirect cost of manufacturing reflected on the manufacturing cost price for each functional modules consisting of entire system through adding a mechanism to reduce unnecessary occurrence of process transactions. In addition, this paper considers connectivity among the functional modules so that manufacturing situations can be influenced on the system to be implemented and includes the system design with monitoring modules and data flow between functional modules.

• Journal of the Korea Safety Management & Science
• /
• v.2 no.2
• /
• pp.155-165
• /
• 2000

Many enterprises are performing the effective database applications with VAN(Value Added Network) or WAN(Web Added Network) . But it is very difficult and expensive. So we suggest low-cost database system within long distance area through personal computers. This system is very powerful for flexibility. It may be estimated it's value highly because they develop the program without high programming skill. This study would be used between company with company and/or between branch with branch, for example, customer claim information, inventory information, product order etc. It is important not importing document but importing data in document. Then end-user can accomplish analysis and decision-making with their own database. It would enhance productivity in many enterprises.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2018.10a
• /
• pp.69-71
• /
• 2018

Looking at Korea's manufacturing industry, there are many old manufacturing plants. In fact, the manufacturing process of the product inventory management and the unit price of the product are all created by using Excel, and the factory is operated by using it. Also, the operator can not predict the failure of the equipment in order to produce the product at work. Problems related to this may result in the loss of the documents during the instruction and work process between the manager and the worker, and the communication between the manager and the worker can not be properly performed, There is appear a situation in which the operation is continued by using the equipment without recognizing in the failure. In this paper, we propose a method for upgrading the aging manufacturing plant to improve the productivity and productivity of the product by predicting the efficient inventory management, unit price management, production volume, and the operator's failure prediction.