SupplyChainManagementIssuesandModelsLecture4.ppt

Supply Chain Management:Issues and ModelsLecture 4: Bullwhip Effect Prof. Dr. Jinxing Xie Department of Mathematical Sciences Tsinghua University, Beijing 100084, China /~jxie Email: jxie@ Voice: (86-10 Fax: (86-10Office: Rm. 1308, New Science Building 牛鞭效应（例） Amplified Demand Distortion (the Bullwhip Effects) Four sources of the bullwhip effect: Demand signal processing Rationing game  Order batching Price variation Bullwhip Effect: An Analytical Model Bullwhip effect Events in each period Variables Demand Process Results for demand signal processing Optimal order-up-to level Optimal order quantity Amplification of order variance Summary Information sharing:Value of information Basic Assumptions Leadtimes Retailer’s ordering decision process Manufacturer’s decision Retailer’s Leadtime Demand Retailer’s Leadtime Demand Retailer’s Ordering Decision For manufacturer: Manufacturer’s leadtime demand Manufacturer’s leadtime demand: No information sharing Manufacturer’s order-up-to level: No information sharing Manufacturer’s leadtime demand: information sharing Manufacturer’s order-up-to level: information sharing Benefits of information sharing Comparing (3.10) with (3.13), one can quantify the benefits of information sharing: Inventory level; Cost evaluation Similar methods can be used to * * 销售总公司 分销商 工厂 零售商 顾客 i) Barilla (意大利面条制造商) PG 批发商 3M (胶带) 零售商 信息流 物流 顾客 ii) P G Bullwhip effect exists even when the leadtime is zero Other causes of bullwhip effects: omitted here Sharing information is needed? The demand is assumed to be a simple autocorrelated AR(1) process (2.1) d 0, -1?1, and ? is i.i.d. normally distributed with mean zero and variance ?2. ? d Supplier (Manufacturer) Retailer Demand * *