• Proceedings of the Korea Society for Industrial Systems Conference
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• 2006.05a
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• pp.235-240
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• 2006

The existing inventory managements bear a relation to forecasting or assumptions. So these methods become more complicated and more expensive systems as time goes. This paper developed a practical inventory system which is called DCC(demand control chart). DCC does not 'forecast' but 'control' the trend of demand without assumptions. According to the trend of sales, DCC adjusts an order quantity considering the capacity of shelf in a store. Specially, DCC is a useful method under FRID system. Besides, this paper introduces EPFR(Every Period Full Replenishment) policy for reducing stocks.

• IE interfaces
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• v.5 no.2
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• pp.19-27
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• 1992

The ABC analysis is a widely used inventory control technique which consists of classifying inventory items into three categories according to annual dollar usage and concentrating managerial efforts on the high value items. But its major weakness is that the classification is somewhat arbitrary and is made in the light of single criterion, the annual usage. In this paper, a modified approach using TOPSIS is proposed where 1) the inventory items are ranked, rather than classified into three categories, in the order of relative importance and 2) the latter is determined by considering the multiple criteria such as annual usage, difficulty of procurement, lead time and shelf life. A case study was performed with the field data from a company producing electronical parts. The rank order produced by TOPSIS was judged quite reasonable by the company inventory control manager.

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.4
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• pp.319-325
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• 2001

Recently. AGV systems are used to serve the raw material to each work stations automatically. There exists a trade-off between the adequate service supply and the number of purchased AGVs. Also, to reduce the overall production cost, the amount of inventory hold on the shop floor should be considered. In this paper, we present a heuristic technique for determining the number of AGVs which includes the net present fixed costs of each station, each purchased AGV, delivering cost, stock inventory cost, and safety stock inventory cost. Secondly, by using a genetic algorithm, the optimal number of AGVs and the optimal reorder quantity at each station are decided. Lastly, to verify then heuristic algorithm, we have done a computer simulation with different GA parameters.

• IE interfaces
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• v.16 no.1
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• pp.111-116
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• 2003

Business integration has been considered as one of the most critical success factors that enable the firms to gain competitive edges. Despite this trend, it has also been found among not a few companies that the activities that should be functionally tied with are performed even independently. In this study, an integrated model of production planning and inventory has been developed. Computerization of the production planning activities is proposed and implemented. We also proposed the reasonable inventory levels of each item using historic data of the items, which are composed of safety stock from the given fill-rate, operating stock from the production patterns, and reserved stock from the production planning. This study has helped the firm to have clearer job definition of the related processes, to tightly control the inventory by setting and tracing the reasonable fill rates for every product, and to quickly respond to the market changes through the computerized production planning process.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.33 no.4
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• pp.69-78
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• 2010

Multi-criteria ABC inventory classification is one of the most widely employed techniques for efficient inventory control, and it considers more than one criterion for categorizing inventory items into groups of different importance. Recently, Ramanathan (2006) proposed a weighted linear optimization (WLO) model for the problem of multi-criteria ABC inventory classification. The WLO model generates a set of criteria weights for each item and assigns a normalized score to each item for ABC analysis. Although the WLO model is considered to have many advantages, it has a limitation that many items can share the same optimal efficiency score. This limitation can hinder a precise classification of inventory items. To overcome this deficiency, we propose a context-dependent DEA based method for multi-criteria ABC inventory classification problems. In the proposed model, items are first stratified into several efficiency levels, and then the relative attractiveness of each item is measured with respect to less efficient ones. Based on this attractiveness measure, items can be further discriminated in terms of their importance. By a comparative study between the proposed model and the WLO model, we argue that the proposed model can provide a more reasonable and accurate classification of inventory items.

• Proceedings of the KSRS Conference
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• 1998.09a
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• pp.382-386
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• 1998

The objectives of this study are to reveal relationship between tree physiology and spectral reflectance on effects of artificial acid rain and to obtain basic data on optimal wave length for forest of LRC sensor on KOMPSAT-2. Three pH levels of artificial acid rain - control, pH4.5 and pH3.0 - were applied to Pinus and Quercus species. Three types of the acid rain were spraied at the amount of 500m1 in every two days. Spectral reflectance data was collected once in a month by using GER 1500 (350~2500nm) or Ll 1800(300~1100nm) Spectroradiometer. The data was measured three times in a pH level. The results of this study are as follows; in April, the spectral reflectance of Pinus species was high in order at the level of pH3.0, control and pH4.5; in May, control, pH3.0 and pH4.5; in June, control, pH4.5 and pH3.0. That of Quercus species was high in the order of control, pH4.5 and pH3.0 in May; in June, control, pH3.0 and pH4.5, especially, within infrared wave length range, control, pH4.5 and ph3.0.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.21 no.48
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• pp.37-52
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• 1998

In many distribution systems important cost reductions and/or service improvements may be achieved by adopting an efficient inventory policy and proper selection of facilities. These efficiency improvements and service enhancements clearly require an integrated approach towards various logistical planning functions. The areas of inventory control and transportation planning need to be closely coordinated. The purpose of this paper is to construct an integrated model that can minimize the total cost of the transportation and inventory systems between multiple origin and destination points, where in origin point i has the supply of commodities and in destination point j requires the commodities. In this case, demands of the destination points are assumed random variables which have a known probability distribution. Using the lot-size reorder-point policy and the safety stock level that minimize total cost we find optimal distribution centers which transport the commodities to the destination points and suggest an optimal inventory policy to the selected distribution center. We also show if a demand greater than one unit will occur at a particular time, we describe the approximate optional replenishment policy from computational results of this lot-size reorder-point policy. This model is formulated as a 0-1 nonlinear integer programming problem. To solve the problem, this paper proposes heuristic computational procedures and a computer program with UNIX C language. In the usefulness review, we show the meaning and validity of the proposed model and exhibit the results of a comparison between our approach and the traditional approach, respectively.

• Journal of Institute of Control, Robotics and Systems
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• v.3 no.5
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• pp.532-541
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• 1997

This article derives an analytic solution to determine the optimal size of multiple noncontinuous process and storage units. The total cost to be minimized consists of the setup cost of noncontinuous processing units and the inventory holding cost of feedstock/product storages. A novel approach, which is called PSW(Periodic Square Wave) model, is applied to represent the material flow among non-continuous units and storages. PSW model presumes that the material flow between unit and storage is periodic square wave shaped. The resulting optimal unit size has similar characteristics with the classical economic lot sizing model such as EOQ(Economic Order Quantity) or EPQ(Economic Production Quantity) model in a sense that the unit size is determined as the balance between setup and inventory holding cost. However, the influence of inventory holding cost of PSW model is different from that of EOQ/EPQ model. EOQ/EPQ model includes only the product inventory holding cost but PSW model includes all inventory holding costs around the non-continuous unit with proportional contribution. PSW model is suitable for analyzing interlinked process-storage system. The optimal lot size of PSW model is smaller than that of EOQ/EPQ model. This is quitea remarkable result considering that the EOQ/EPQ model has been is widely used since last half century.

• The Journal of Society for e-Business Studies
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• v.6 no.3
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• pp.1-16
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• 2001

In this paper, we introduced a POS(Point of Sale) system for a wallpaper company. We designed the database schema for the POS system, and proposed various application areas of the POS system. Especially, we discussed such application areas as inventory control, marketing, product development, and distribution channel. The quality of product management is enhanced by precise ABC inventory control and safety stock control. Marketing strategies can be more precisely established, and their effects can be measured. The development time can be shortened and new products can be developed based on the real market demands. Distributors can improve their management quality using precise sales data.

• Journal of Distribution Science
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• v.11 no.7
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• pp.23-30
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• 2013

Purpose - The study attempts to investigate the relationship between inventory management and firm performance using a multi-dimensional aspect of inventory management with respect to lean management practices across countries. Research design, data, and methodology - 1643 manufacturing firms from Japan and the US that SIC ranges from 2000 to 3999 were chosen to conduct the empirical test. This study employs hierarchical OLS regression analysis to examine the impact of control variables, ABI, EBI, and the interaction between ABI and EBI on firm performance. Results - The result indicates that in Japan high level of inventory negatively influences the accounting flows of business, while US manufactures exhibit strong positive impact of ELI on firm performance across accounting and market measures. The results show that the complementarity between the amount and the speed of inventory does exist. Except for Tobin's q, the sign of interaction term coefficient is negative, suggesting that when the amount of inventory increases and it stays longer in a firm, market values, ROS, and ROA suffers. Conclusions - The major finding of this study is that there exist some complementarities between the scope and implication of inventory management for lean strategy across countries, particularly in U.S. and Japanese firms.