第十三章--最优产品可获性水平的确定----(《供应链管理》PPT课件)

13–1Copyright©2016PearsonEducation,Inc.Copyright©2016PearsonEducation,Inc.第十三章最优产品可获性水平的确定13–2Copyright©2016PearsonEducation,Inc.Copyright©2016PearsonEducation,Inc.产品可获性水平的重要性•产品可获性水平可用周期服务水平或满足率来度量，用来衡量现有库存可以满足的顾客需求占总需求的比率。•又称顾客服务水平。•是衡量供应链响应性最主要的指标。•供应链需要在产品可获性水平和库存成本之间取得平衡：–高水平的产品可获性提升响应能力并吸引顾客，从而增加收益。–高水平的产品可获性需要大量的库存予以保证，从而又会增加供应链的成本。•最优产品可获性水平的高低，取决于公司认为怎样的产品可获性水平能使公司利润最大化。13–3Copyright©2016PearsonEducation,Inc.Copyright©2016PearsonEducation,Inc.最优产品可获性水平的影响因素•超储成本，Co•欠储成本，Cu•只有在需求不确定的情况下，确定最优产品可获性水平才是有意义的。•在过去的十年间，企业逐渐正视不确定性的存在，并开始研究包含不确定性度量方法的预测。•相比使用一致性预测方法，将不确定性纳入预测之中，并依据最优产品可获性水平进行订货决策，可以为企业增加收益。13–4Copyright©2016PearsonEducation,Inc.Copyright©2016PearsonEducation,Inc.里昂·比恩公司的例子需求Di(百件)概率pi需求小于或等于Di的概率Pi需求大于Di的概率40.010.010.9950.020.030.9760.040.070.9370.080.150.8580.090.240.7690.110.350.65100.160.510.49110.200.710.29120.110.820.18130.100.920.08140.040.960.04150.020.980.02160.010.990.01170.011.000.0013–5Copyright©2016PearsonEducation,Inc.Copyright©2016PearsonEducation,Inc.里昂·比恩公司的例子额外100件滑雪服的预期利润=5500×Prob(需求≥1100)-500×Prob(需求1100)=5500×0.49-500×0.51=2440(美元)订购1300件滑雪服的预期利润=49900+2440+1240+580=54160(美元)预期需求=∑Dipi=1026预期利润=49900(美元)13–6Copyright©2016PearsonEducation,Inc.Copyright©2016PearsonEducation,Inc.里昂·比恩公司的例子多购100件预期边际收益(美元)预期边际成本(美元)预期边际贡献(美元)第11个100件5,500x0.49=2,695500x0.51=2552,695–255=2,440第12个100件5,500x0.29=1,595500x0.71=3551,595–355=1,240第13个100件5,500x0.18=990500x0.82=410990–410=580第14个100件5,500x0.08=440500x0.92=460440–460=–20第15个100件5,500x0.04=220500x0.96=480220–480=–260第16个100件5,500x0.02=110500x0.98=490110–490=–380第17个100件5,500x0.01=55500x0.99=49555–495=–44013–7Copyright©2016PearsonEducation,Inc.Copyright©2016PearsonEducation,Inc.里昂·比恩公司的例子13–8Copyright©2016PearsonEducation,Inc.Copyright©2016PearsonEducation,Inc.季节性产品每季只进行一次订货情况下的最优周期服务水平Co:单位产品的超储成本，Co=c–sCu:单位产品的欠储成本，Cu=p–cCSL*:最优周期服务水平O*:相应的最优订货批量多订购一单位产品的预期收益=(1–CSL*)(p–c)多订购一单位产品的预期成本=CSL*(c–s)预期边际贡献=(1–CSL*)(p–c)–CSL*(c–s)13–9Copyright©2016PearsonEducation,Inc.Copyright©2016PearsonEducation,Inc.季节性产品每季只进行一次订货情况下的最优周期服务水平CSL*=Prob(Demand£O*)=p–cp–s=CuCu+Co=11+Co/Cu()O*=F–1(CSL*,m,s)=NORMINV(CSL*,m,s)Expectedprofit=(p–s)mFsO–msæèçöø÷–(p–s)sfsO–msæèçöø÷–O(c–s)F(O,m,s)+O(p–c)1–F(O,m,s)éëùû13–10Copyright©2016PearsonEducation,Inc.Copyright©2016PearsonEducation,Inc.季节性产品每季只进行一次订货情况下的最优周期服务水平Expectedprofits=(p–s)mNORMDIST(O–m)/s,0,1,1éëùû–(p–s)sNORMDIST(O–m)/s,0,1,0éëùû–O(c–s)NORMDIST(O,m,s,1)+O(p–c)1–NORMDIST(O,m,s,1éëùû13–11Copyright©2016PearsonEducation,Inc.Copyright©2016PearsonEducation,Inc.季节性产品最优周期服务水平的计算需求m=350副，s=100副，c=100美元，p=250美元季末未售出的滑雪板处理价=85美元，销售季节每副滑雪板的库存持有成本=5美元。s=85–5=80(美元)Cu=p–c=250–100=150(美元)Co=c–s=100–80=20(美元)CSL*=Prob(Demand£O*)=CuCu+Co=150150+20=0.88O*=NORMINV(CSL*,m,s)=NORMINV(0.88,350,100)=46813–12Copyright©2016PearsonEducation,Inc.Copyright©2016PearsonEducation,Inc.季节性产品最优周期服务水平的计算Expectedprofits=(p–s)mNORMDIST(O–m)/s,0,1,1éëùû–(p–s)sNORMDIST(O–m)/s,0,1,0éëùû–O(c–s)NORMDIST(O,m,s,1)+O(p–c)1–NORMDIST(O,m,s,1éëùû=59,500NORMDIST(1.18,0,1,1)–17,000NORMDIST(1.18,0,1,0)–9,360NORMDIST(468,350,100,1)+70,2001–NORMDIST(468,350,100,1)éëùû=$49,14613–13Copyright©2016PearsonEducation,Inc.Copyright©2016PearsonEducation,Inc.季节性产品最优周期服务水平的计算预期超储量=(O–m)FSO–msæèçöø÷+sfSO–msæèçöø÷预期超储量=(O–m)NORMDIST(O–m)/s,0,1,1éëùû+sNORMDIST(O–m)/s,0,1,0éëùû预期欠储量=(m–O)1–FSO–msæèçöø÷éëêùûú+sfSO–msæèçöø÷预期欠储量=(m–O)1–NORMDIST(O–m)/s,0,1,1éëùûéëùû+sNORMDIST(O–m)/s,0,1,0éëùû13–14Copyright©2016PearsonEducation,Inc.Copyright©2016PearsonEducation,Inc.计算预期超储量和欠储量μ=350,σ=100,O=450预期超储量=(O–m)NORMDIST(O–m)/s,0,1,1éëùû+sNORMDIST(O–m)/s,0,1,0éëùû=(450–350)NORMDIST(450–350)/100,0,1,1éëùû+100NORMDIST(450–350)/100,0,1,0éëùû=108预期欠储量=(m–O)1–NORMDIST(O–m)/s,0,1,1éëùûéëùû+sNORMDIST(O–m)/s,0,1,0éëùû=(350–450)1–NORMDIST(450–350)/100,0,1,1éëùûéëùû+100NORMDIST(450–350)/100,0,1,0éëùû=813–15Copyright©2016PearsonEducation,Inc.Copyright©2016PearsonEducation,Inc.数量折扣下的一次订货1.由Co=c–s和Cu=p–c，计算无折扣下的最优周期服务水平CSL*和最优订货批量O*。•计算订货批量为O*时的预期利润。2.由Co=cd–s和Cu=p–cd，计算数量折扣下的最优周期服务水平CSL*d和最优订货批量O*d。•如果O*d≥K，计算订货批量为O*d时的预期利润。•如果O*dK，计算订货批量为K时的预期利润。3.如果步骤1下的利润更高，则订货批量取O。•如果步骤2下的利润更高，若O*d≥K订货批量取O*d，若O*dK订货批量取K。13–16Copyright©2016PearsonEducation,Inc.Copyright©2016PearsonEducation,Inc.计算数量折扣下的周期服务水平•第1步，计算在正常价格c=50美元下的最优订货批量：Cu=p–c=200–50=150(美元)Co=c–s=50–0=50(美元)CSL*=Prob(Demand£O*)=CuCu+Co=150150+50=0.75O*=NORMINV(CSL*,m,s)=NORMINV(0.75,150,40)=177订购177套下的预期利润=19,958(美元)13–17Copyright©2016PearsonEducation,Inc.Copyright©2016PearsonEducation,Inc.计算数量折扣下的周期服务水平•第2步，我们考虑折扣价格cd=45美元：Cu=p–c=200–45=155(美元)Co=c–s=45–0=45(美元)CSL*=Prob(Demand£O*)=CuCu+Co=150150+45=0.775O*=NORMINV(CSL*,m,s)=NORMINV(0.775,150,40)=180订货200套下的预期利润=20,595(美元)13–18Copyright©2016PearsonEducation,Inc.Copyright©2016PearsonEducation,Inc.连续补货型产品的期望周期服务水平•有两种极端的情况必须考虑：1.产品缺货期间的全部需求积累起来，在库存得到补充之后再予以满足。2.产品缺货期间的全部需求丢失。13–19Copyright©2016PearsonEducation,Inc.Copyright©2016PearsonEducation,Inc.连续补货型产品的期望周期服务水平Q:补货批量S:订货的固定成本ROP:再订货点D:单位时间内的平均需求:单位时间内需求的标准差ss:安全库存，ss=ROP–DLCSL:周期服务水平C:单位成本h:单位时间内库存持有成本比例H:每件产品单位时间内的库存持有成本，H=h