供應(yīng)鏈不匹配成本ppt課件(已修改)
2024-11-15 17:20 本頁面
【正文】 Slide ??， The Newsvendor Model 報(bào)童模型 Slide ??， “ 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 (., 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 (., you under ordered). Cu is the increase in profit you would have enjoyed had you ordered one more unit. Slide ??， 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 (1F(Q)) 010203040506070800 800 1600 2400 3200 4000 4800 5600 6400Qth u n i t o rd e re dExpected gain or loss .E x p e c t e d g a i nE x p e c t e d l o s s? As more units are ordered, the expected benefit from ordering one unit decreases while the expected loss of ordering one more unit increases. Slide ??， 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. （臨界比或關(guān)鍵比例） ? Hence, to maximize profit, choose Q such that we don’t have lost sales (., demand is Q or lower) with a probability that equals the critical ratio ? ?? ?QFCQFC uo ???? 1)(uouCCCQF??)(Slide ??， The Newsvendor Model: Performance measures 績效指標(biāo) Slide ??， Newsvendor model performance measures ? For any order quantity we would like to evaluate the following performance measures: ? Expected lost sales （期望銷售損失） ? The average number of units demand exceeds the order quantity ? Expected sales （期望銷售） (pared to expected demand) ? The average number of units sold. ? Expected left over inventory（期望售后剩余庫存） ? The average number of units left over at the end of the season. ? Expected profit ? Expected fill rate （期望訂單完成率） ? The fraction of demand that is satisfied immediately ? Instock probability（存貨滿足概率） ? Probability all demand is satisfied ? Stockout probability（缺貨概率） ? Probability some demand is lost Slide ??， formula ? Expected sales = m Expected lost sales ? m : Expected demand ? L(z): loss function (標(biāo)準(zhǔn)正態(tài) )損失函數(shù) , ? 隨機(jī)變量超過一個(gè)固定值的期望值之和。 ? Expected Left Over Inventory = Q Expected Sales ( )E x p e c t e d l o s t s a l e s L z???? ?? ?zN o r m s d i s tzzN o r m di s tzL ??? 1*)0,1,0,()
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