| Summary |
Student：Chih-Shen Chen, 2006.06
Institute of Traffic and Transportation National Chiao Tung University
In the research field of bullwhip effect, most studies discussed the impact of lead time and demand forecast method to bullwhip effect under a simple two-stage supply chain structure. The purpose of this study is to analyze the influence of different supply chain strategies under a two-stage supply chain structure on the bullwhip effect, average inventory and the out of stock rate.
Four supply chain strategies are selected in this study, which include just in time strategy (JIT), continuous replenishment program strategy (CRP), simple two-stage strategy etc. In the simple two-stage supply chain, it uses moving averaging method in demand forecast, order-up-to policy in inventory strategy. In JIT strategy, the demand is divided into order demand and non-order demand. Order demand can be reflected in order quantity in advance, and the non-order demand need to be predicted. The CRP strategy just need to replenish the inventory to the upper limit of inventory. Another strategy of CRP sets a safety inventory standard, and the quantity ordered is the difference of the upper limit and the inventory at that time, whenever the inventory is under the safety standard.
Based on the models developed in this study, and results of simulation and case study, we can find the relation between the control variables of all supply chain strategies and the bullwhip effect, average inventory, out of stock rate can be analyzed. In simple two-stage supply chain and CRP strategy, damping the bullwhip effect result in the increase of inventory and the out of stock rate, only JIT can decrease the inventory and the out of stock rate at the same time when the proportion of order demand is increased. In the bullwhip effect, higher proportion of order demand, will reduce the difference of upstream and downstream supply chain.
Besides, change of lead time has absolute impact on the bullwhip effect, average inventory, out of stock rate for all the four supply chain strategies.
The longer the lead time, the higher the bullwhip effect and inventory, as well as the higher out of stock rate. |
