供应链不匹配成本.pptVIP

The Newsvendor Model 报童模型 “Too much” and “too little” costs Co = overage cost The cost of ordering one more unit than what you would have ordered had you known demand. In other words, suppose you had left over inventory (i.e., you over ordered). Co is the increase in profit you would have enjoyed had you ordered one fewer unit. Cu = underage cost The cost of ordering one fewer unit than what you would have ordered had you known demand. In other words, suppose you had lost sales (i.e., you under ordered). Cu is the increase in profit you would have enjoyed had you ordered one more unit. Balancing the risk and benefit of ordering a unit Ordering one more unit increases the chance of overage … Expected loss on the Qth unit = Co x F(Q) F(Q) = Distribution function of demand = Prob{Demand = Q) … but the benefit/gain of ordering one more unit is the reduction in the chance of underage: Expected gain on the Qth unit = Cu x (1-F(Q)) Newsvendor expected profit maximizing order quantity To maximize expected profit order Q units so that the expected loss on the Qth unit equals the expected gain on the Qth unit: Rearrange terms in the above equation - The ratio Cu / (Co + Cu) is called the critical ratio. （临界比或关键比例） Hence, to maximize profit, choose Q such that we don’t have lost sales (i.e., demand is Q or lower) with a probability that equals the critical ratio The Newsvendor Model: Performance measures 绩效指标 Newsvendor model performance measures For any order quantity we would like to evaluate the following performance measures: Expected lost sales （期望销售损失） The average number of units demand exceeds the order quantity Expected sales （期望销售）(compared to expected demand) The average number of units sold. Expected left over inventory（期望售后剩余库存） The average number of units left over at the end of the season. Expected profit Expected fill rate （期望订单完成率） The fraction of demand that is satisfied immediately In-stock probability（存货满足概率） Probability all demand is satisf