• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.32 no.1
• /
• pp.1-10
• /
• 2009

Inventory Management has become a very important issue in supply chain management, because inventories may be used as a means to accomplish the certain strategic goals in company decisions. RFID(radio frequency identification) technology is used to help manage inventories. It is known that the ideal control of inventories is to replenish item by item. This paper points out several misinterpretations from the Wal-mart report presented in '07 Seoul Forum and suggests the new direction of RFID application. In this paper we consider RFID as not 'identification technology' but 'information technology.' The 'RF-Kanban' suggested here is adopted from the'Kanban'concept of TPS(Toyota Production System). The RF-Kanban system shows the easier control for replenishing various items in boxes. Lots of inventories can be reduced through RF-Kanban System. This work develops the protocol of RF-Kanban and introduces the case study for easier understanding.

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

• Journal of the Korean Operations Research and Management Science Society
• /
• v.21 no.2
• /
• pp.17-33
• /
• 1996

Automatic transfer defined as an integrated system with a number of workstations, interstation storage buffers, automatic device and a control system, play a major role in ass production systems. Due to high capital investment needed for an automatic transferline, greater care should be taken in its design so as to maximize the system performance. One may to control the system performance is to control buffer storage. To control the interstation work-in-process inventory, we propose dual limit switches which control the buffer storage with two parameters, R and r. Under the policy, proceding station is forced down when the inventory level in the buffer reaches R until the level falls to r. For the model developed, we analyze the system characteristics and find the optimal control parameters with a serach procedure.

• IE interfaces
• /
• v.10 no.1
• /
• pp.119-134
• /
• 1997

The management of blood inventory is very important within the medical care system. The efficient management of blood supplies and demands for transfusions is of great economic and social importance to both hospitals and patients. For any blood type, there is a complex interaction among the optimal inventory level, daily demand level, daily supply level, transfusion to crossmatch ratio, crossmatch release period, issuing policy and the age of arriving units that determine the shortage and outdate rate. In this paper, we develop an efficient decision rule for blood inventory management in a hospital blood bank which can support efficient hospital blood inventory management using simulation. The primary use of the efficient decision rule will be to establish minimum cost function which consists of inventory levels, period in inventory, outdate and shortage rate for whole blood and various component inventories for a hospital blood bank or a transfusion service. If the administrator compute the mean daily demand for each blood type, the mean daily supply for each blood type, the length of the crossmatch release period and the average transfusion to crossmatch ratio, then it is possible to apply the efficient decision rule to compute the optimal inventory level, inventory period, outdate and shortage rate. This rule can also be used as a decision support system that allows the blood bank administrator to do sensitivity analysis related to controllable blood inventory parameters.

• Korean Management Science Review
• /
• v.11 no.1
• /
• pp.73-90
• /
• 1994

Recently the recongnition of Logistics becomes important to enterpries as a means for improving their competition, but the Korea enterpries falls for far behind in management techniques for analyzing realities and problems in the Logistics compare to the advanced countries. Especially the function of inventory control which is most undeveloped in them should be improved in Korea. Inventory is very important in Logistics, but there exists trade-off between inventory level and customer in the service level. It is difficult to coordinate both the reduction in the inventory level and the enhancement in the service level. Its effective technique is a DRP system. In general, it deals with arborescent distribution network in which a given channel member has a single source of supply. This article aims to present a DRP system, and more a DRP system which is flexible and responsive in the multisourcing, multi-echelon distribution network. Related research issues are discussed. Finally, using a DRP system on logistics and the management performance. So we can help the physical distribution improvement of the Korean enterprises.

• Proceedings of the Society of Korea Industrial and System Engineering Conference
• /
• 2002.05a
• /
• pp.189-194
• /
• 2002

As a environment of SCM is issued recently, many enterprises are concerned about inventory control for an efficiency of operation and reliablity. The goal of them is to match up to improving of facilities and redoing of inventory cost. To put an efficiency in the operation rate of facilites, A moderate provision of spare parts for that would come into a matter. This study designs two-echelon spare parts distribution system and sees over the relationship between operating rate and inventories of spare parts. and then it determines fitting inventories and investment cost considering an operating rate.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.22 no.1
• /
• pp.59-73
• /
• 1997

This papaer analyzes a system with consists of two workstations that are separated by finite buffer storage. In this system, we assume that the processing time in each station in a random variable and each station is not vulnerable to failure. To control the in-process inventory in the serial production system we use the (R, r) policy which is similar to the (s, S) policy in the inventory theory. Under the (R, r) policy the preceding station is forced down when the inventory level in the buffer reaches R and starts operation again when the inventory level falls to r. For the model developed, we analyze the system characteristics and the system performances.

• Journal of Korean Society for Quality Management
• /
• v.18 no.2
• /
• pp.9-17
• /
• 1990

This paper deals with a FOQ( ; fixed-order quantity) model for spare-part inventory control. In a spare-part inventory problem, stock depletion arises not from external market demand but from internal demand resulting from failures of parts in use. The problem differs from the classical inventory problem in that the demand for a failed part never arises more during stockout period, since the unit remains inoperative when stockout occurs until the failed part is replaced by new one. In the problem under consideration, n identical units are operating simultaneously and failed one is replaced immediately by new one if on-hand spares remain. In order to replenish spares, an order with quantity Q is placed whenever the number of on-hand spares falls to levels. The average annual cost of operating the spare-part inventory system is derived under the assumption that both lifetime of a part and replenishment lead-time distributions are exponential.

• Industrial Engineering and Management Systems
• /
• v.15 no.4
• /
• pp.354-363
• /
• 2016

Due to uncertain environment, various parameters such as price, queuing length, warranty, and so on influence on inventory models. In this paper, an inventory-queuing-pricing problem with continuous review inventory control policy and batch arrival queuing approach, is presented. To best of our knowledge, (I) demand function is stochastic and price dependent; (II) due to the uncertainty in real-world situations, a fuzzy programming approach is applied. Therefore, the presented model with goal of maximizing total profit of system analyzes the price and order quantity decision variables. Since the proposed model belongs to NP-hard problems, Pareto-based approaches based on non-dominated ranking and sorting genetic algorithm are proposed and justified to solve the model. Several numerical illustrations are generated to demonstrate the model validity and algorithms performance. The results showed the applicability and robustness of the proposed soft-computing-based approaches to analyze the problem.

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