• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.5
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• pp.181-188
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• 2021

In preparing a aggregate production plan(APP), the transportation method generally uses a linear planning(LP) software package for TSM(transportation simplex method), which seeks initial solutions with either NCM, LCM, or VAM specialized in transportation issues and optimizes them with either SSM or MODI. On the other hand, this paper proposes a transportation method that easily, quickly, and accurately prepares a APP without software package assistance. This algorithm proposed simply assigned to least cost-first, and minimized the inventory periods. Applying the proposed algorithm to 6-benchmarking data, this algorithm can be obtained better optimal solution than VAM or LP for 4 data, and we obtain the same results for the remained 2 data.

• Korean Management Science Review
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• v.29 no.3
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• pp.107-120
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• 2012

In this paper we propose an effective genetic algorithm for solving the integrated inventory and routing problem of supply chain composed of multi-warehouses and multi-retailers. Unlike extant studies dealing with integrated inventory and routing problem of supply chain, our model incorporates more realistic aspect such as positive inventory at the multi-warehouses under the assumption of inventory policy of power of two-replenishment-cycle. The objective is to determine replenishment intervals for the retailers and warehouses as well as the vehicles routes so that the total cost of delivery and inventory cost is minimized. A notable feature of our algorithm is that the procedure for evaluating the fitness of objective function has the computational complexity closing to linear function. Computational results show effectiveness of our algorithm.

• Journal of the Korea Society for Simulation
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• v.10 no.1
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• pp.35-50
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• 2001

Managing multi-echelon inventory systems has gained importance over the last decade mainly because integrated control of supply chains consisting of several processing and distribution stages has become feasible through modern information technology. Determination of optimal inventory policy for multi-echelon supply chain is made difficult by the complex interaction between the different levels. In this paper, we investigate performance of five inventory policies (fixed quantity order policy, fixed interval order policy, compromised order policy, lead time-fixed quantity order policy, and mixed order policy) in a multi-echelon supply chain by using a simulation model constructed with AweSim simulation language. The results of the simulation study show that the mixed order policy is the best among five inventory policies in the most test problems except the case when the stockout cost per unit is much higher than the inventory holding and transportation costs per unit.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.7
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• pp.750-755
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• 2014

Product shortage which causes backordering and/or lost sales cost is very popular in chemical industries, especially in commodity polymer business. This study deals with backordering cost in the supply chain optimization model under the framework of process-inventory network. Classical economic order quantity model with backordering cost suggested optimal time delay and lot size of the final product delivery. Backordering can be compensated by advancing production/transportation of it or purchasing substitute product from third party as well as product delivery delay in supply chain network. Optimal solutions considering all means to recover shortage are more complicated than the classical one. We found three different solutions depending on parametric range and variable bounds. Optimal capacity of production/transportation processes associated with the product in backordering can be different from that when the product is not in backordering. The product shipping cycle time computed in this study was smaller than that optimized by the classical EOQ model.

• Journal of the Korea Safety Management & Science
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• v.10 no.3
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• pp.217-225
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• 2008

The inventory routing problem (IRP) is an important area of Supply Chain Management. The objective function of IRP is the sum of transportation cost and inventory cost. We propose an Artificial Immune System(AIS) to solve the IRP. AIS is one of natural computing algorithm. An hyper mutation and an vaccine operator are introduced in our research. Computation results show that the hyper mutation is useful to improve the solution quality and the vaccine is useful to reduce the calculation time.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.25 no.4
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• pp.16-21
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• 2002

This paper refer to the trade-off between delivery frequency and amount between supplier and discountstores. Discountstores prefer frequent delivery of small amount because of limited storage space, while suppliers prefer less frequent delivery of large amount in order to save transportation cost In this paper we propose a heuristic algorithm to determine the amount of order and the delivery frequency which decreases the expected length of stockout. We also evaluate various order policies for vendor managed inventory system using simulation with real data.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2007.05a
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• pp.198-208
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• 2007

Recently business enterprises have forced to face in fierce competition in today's global markets due to the short life cycles of products and the higher expectation of customers. Together with continuing advances in communications and transportation technologies, these environments have motivated the continuous evolution of the supply chain and the management techniques. This paper consider three-echelon inventory system which consist of one manufacturer, one distributor and N retailers for a single product under assumption of constant demand. This paper propose the inventory replenishment period using heuristic method and order policy through coordination of inventory replenishment period. The simulation results show that decrease the total cost of the three-echelon inventory system.

• Journal of Korean Institute of Industrial Engineers
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• v.34 no.4
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• pp.425-432
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• 2008

While the Vendor-Managed Inventory(VMI) is a convenient inventory replenishment policy for the customer company, the supplier usually bears the burden of higher inventory and urgent shipments to avoid shortage. Recently some manufacturers begin to fix the production schedule for the next few days (such as three days). Utilizing that information can improve the efficiency of the VMI. In this study, we present a myopic optimization model using a mixed inter programming; and a heuristics algorithm. We compare the performance of the two proposed methods with the existing (s, S) reorder policy. We consider the total cost as the sum of transportation cost and inventory cost at the customer's site. Numerical tests indicate that the two proposed methods significantly reduce the total cost over the (s, S) policy.

• Journal of the Korean Operations Research and Management Science Society
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• v.21 no.2
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• pp.95-109
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• 1996

In automobile industry, the depot (distribution center) system is utilized to adjust the inventory and to supply the demands to the firm timely. In case of the small lot demands of short delivery cycle and the long distance from the parts manufacturing to the firm, the depot system is very important. In this paper, a model to minimize the sum of costs of holding, inventory and transportation, is proposed to determine the optimal quantities of production and transportation in JTT system. Finally, computational results that verify the effectiveness of the proposed model are demonstrated.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.32 no.4
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• pp.45-52
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• 2009

The objective of this was to improve a transportation cost relation between Central Distribution Centers(CDCs) and Regional Distribution Centers(RDCs), to control inventory cost concerning safety stock for each service level, by reviewing distribution steps connecting CDCs and RDCs under the price discount. It was also to examine and compare operating costs for the following two alternative suggestions for setting the service standard as a counter measure for a stock-out of the distribution network system management. First, provision by dispersing the safety stock to the CDCs and RDCs; and second, exclusive provision of the safety stock only to the RDCs. The cost comparison analysis was made for each category of purchase costs, regular transportation costs, express transportation costs, and inventory holding costs.