供應鏈管理(第11、12講)

Chapter7

ManagingEconomiesofScaleintheSupplyChain:CycleInventorySupplyChainManagement10-1OutlineRoleofCycleInventoryinaSupplyChainEconomiesofScaletoExploitFixedCostsEconomiesofScaletoExploitQuantityDiscountsShort-TermDiscounting:TradePromotionsEstimatingCycleInventory-RelatedCostsinPractice2第7章獲取供應鏈規(guī)模經濟的手段：循環(huán)庫存一、循環(huán)庫存在供應鏈中的作用二、利用固定成本獲取規(guī)模經濟三、利用數(shù)量折扣獲取規(guī)模經濟四、短期折扣：商業(yè)促銷五、在實踐中估測與循環(huán)庫存相關的費用3循環(huán)庫存產生原因——規(guī)模經濟大批量生產與采購訂購與運輸數(shù)量折扣與促銷4RoleofInventoryintheSupplyChainCostAvailabilityEfficiencyResponsiveness5RoleofCycleInventory

inaSupplyChainLot,orbatchsize:quantitythatasupplychainstageeitherproducesorordersatagiventimeCycleinventory:averageinventorythatbuildsupinthesupplychainbecauseasupplychainstageeitherproducesorpurchasesinlotsthatarelargerthanthosedemandedbythecustomerQ=lotorbatchsizeofanorderD=demandperunittimeInventoryprofile:plotoftheinventorylevelovertime

(Fig.7.1)Cycleinventory=Q/2(dependsdirectlyonlotsize)Averageflowtime=Avginventory/AvgflowrateAverageflowtimefromcycleinventory=Q/(2D)6RoleofCycleInventory

inaSupplyChainQ=1000unitsD=100units/dayCycleinventory=Q/2=1000/2=500=AvginventorylevelfromcycleinventoryAvgflowtime=Q/2D=1000/(2)(100)=5daysCycleinventoryadds5daystothetimeaunitspendsinthesupplychainLowercycleinventoryisbetterbecause:AverageflowtimeislowerWorkingcapitalrequirementsarelowerLowerinventoryholdingcosts7RoleofCycleInventory

inaSupplyChainCycleinventoryisheldprimarilytotakeadvantageofeconomiesofscaleinthesupplychainSupplychaincostsinfluencedbylotsize:Materialcost=CFixedorderingcost=SHoldingcost=H=hC(h=costofholding$1ininventoryforoneyear)Primaryroleofcycleinventoryistoallowdifferentstagestopurchaseproductinlotsizesthatminimizethesumofmaterial,ordering,andholdingcostsIdeally,cycleinventorydecisionsshouldconsidercostsacrosstheentiresupplychain,butinpractice,eachstagegenerallymakesitsownsupplychaindecisions–increasestotalcycleinventoryandtotalcostsinthesupplychain8循環(huán)庫存在供應鏈中的作用循環(huán)庫存指供應鏈中建立的平均庫存量Q：訂購批量R：單位時間需求量（假設需求量不變）循環(huán)庫存＝批量庫存/2＝Q/2循環(huán)庫存平均周轉時間＝循環(huán)庫存/需求量＝Q/2R為減少市場波動，公司理想循環(huán)庫存一般較小TQ9EconomiesofScale

toExploitFixedCostsHowdoyoudecidewhethertogoshoppingataconveniencestoreoratSam’sClub?Lotsizingforasingleproduct(EOQ)10EconomiesofScale

toExploitFixedCostsAnnualdemand=DNumberofordersperyear=D/QAnnualmaterialcost=CDAnnualordercost=(D/Q)SAnnualholdingcost=(Q/2)H=(Q/2)hCTotalannualcost=TC=CD+(D/Q)S+(Q/2)hCFigure7.2showsvariationindifferentcostsfordifferentlotsizes11FixedCosts:OptimalLotSize

andReorderInterval(EOQ)

D: AnnualdemandS: SetuporOrderCostC: Costperunith: HoldingcostperyearasafractionofproductcostH: HoldingcostperunitperyearQ: LotSizeT: ReorderintervalMaterialcostisconstantandthereforeisnotconsideredinthismodel12利用固定成本獲取規(guī)模經濟單一產品批量規(guī)模Q（經濟訂購批量）R＝產品年需求量S＝每次訂購固定成本C＝單位產品購買價格成本H＝每年存儲成本年原料價格成本＝CR年訂購次數(shù)＝R/Q年訂購成本＝（R/Q）*S年存儲成本＝（Q/2）H=(Q/2)hc年總成本TC＝CR+（R/Q）*S+（Q/2）hc13年總成本TC＝CR+（R/Q）*S+（Q/2）hc等式右邊對q一階求導，等于0時，得最佳訂購批量Q*=注：h和R必須要有相同時間單位n＝R/Q*＝14批量規(guī)模成本總成本儲存成本訂購成本原材料成本Q*15Example7.1Demand,D=12,000computersperyeard=1000computers/monthUnitcost,C=$500Holdingcostfraction,h=0.2Fixedcost,S=$4,000/orderQ*=Sqrt[(2)(12000)(4000)/(0.2)(500)]=980computersCycleinventory=Q/2=490Flowtime=Q/2d=980/(2)(1000)=0.49monthReorderinterval,T=0.98month16Example7.1(continued)Annualorderingandholdingcost==(12000/980)(4000)+(980/2)(0.2)(500)=$97,980SupposelotsizeisreducedtoQ=200,whichwouldreduceflowtime:Annualorderingandholdingcost==(12000/200)(4000)+(200/2)(0.2)(500)=$250,000Tomakeiteconomicallyfeasibletoreducelotsize,thefixedcostassociatedwitheachlotwouldhavetobereduced17Example7.2Ifdesiredlotsize=Q*=200units,whatwouldShave

tobe?D=12000unitsC=$500h=0.2UseEOQequationandsolveforS:S =[hC(Q*)2]/2D=[(0.2)(500)(200)2]/(2)(12000)=$166.67Toreduceoptimallotsizebyafactorofk,thefixedordercostmustbereducedbyafactorofk2

18例：bestbuy公司采購電腦，月需求1000臺，固定成本每次4000，進價每臺500，零售商庫存成本占20％，求Q*解：年需求量R=1000*12=12000每批訂購成本S=4000單位采購成本C=500年存儲成本h＝0.2Q*=（（2*12000*4000）/（0.2*500））1/2＝980循環(huán)庫存＝Q*/2=490年訂購次數(shù)＝R/Q*=120000/980=12.24訂購和存儲成本＝（R/Q*）S+（Q*/2）hC=97980平均周轉時間＝Q*/2R=490/1200=0.041年＝0.49月19拓展：A、如果批量規(guī)模1100，而不是980，則：訂購次數(shù)＝12000/1100＝10.9總成本＝10.9*4000+1100/2*0.2*500＝43600+55000＝98600批量規(guī)模從980到1100，增加10％，總成本從97980到98600，僅增加0.6％。20B、假設月需求增加到4000每月（增長4倍），最佳規(guī)模批量和訂購次數(shù)各自增加2倍，平均周轉時間減少至1/2。Q*=年訂購次數(shù)＝R/Q*平均周轉時間＝Q*/2R結論：如果批量規(guī)模最佳，需求量增加，循環(huán)庫存周轉時間會減少。21C、如果批量規(guī)模為200，則：年庫存成本＝（R/Q）*S+(Q/2)hC＝（12*1000/200）*4000+（200/2）0.2*500=250000>>97980為了減少批量規(guī)模，只能減少固定成本。如果期望批量規(guī)模為200，則Q*=S=(hC(Q*）2)/(2*R)=0.2*500*200*200/(2*12000)=166.7<<400022KeyPointsfromEOQModelIndecidingtheoptimallotsize,thetradeoffisbetweensetup(order)costandholdingcost.Ifdemandincreasesbyafactorof4,itisoptimaltoincreasebatchsizebyafactorof2andproduce(order)twiceasoften.Cycleinventory(indaysofdemand)shoulddecreaseasdemandincreases.Iflotsizeistobereduced,onehastoreducefixedordercost.Toreducelotsizebyafactorof2,ordercosthastobereducedbyafactorof4.23EconomiesofScaleto

ExploitQuantityDiscountsAll-unitquantitydiscountsMarginalunitquantitydiscountsWhyquantitydiscounts?CoordinationinthesupplychainPricediscriminationtomaximizesupplierprofits24QuantityDiscountsLotsizebasedAllunitsMarginalunitVolumebasedHowshouldbuyerreact?Whatareappropriatediscountingschemes?25All-UnitQuantityDiscountsPricingschedulehasspecifiedquantitybreakpointsq0,q1,…,qr,whereq0=0Ifanorderisplacedthatisatleastaslargeasqibutsmallerthanqi+1,theneachunithasanaverageunitcostofCiTheunitcostgenerallydecreasesasthequantityincreases,i.e.,C0>C1>…>Cr

Theobjectiveforthecompany(aretailerinourexample)istodecideonalotsizethatwillminimizethesumofmaterial,order,andholdingcosts26All-UnitQuantityDiscountProcedure(differentfromwhatisinthetextbook)Step1:CalculatetheEOQforthelowestprice.Ifitisfeasible(i.e.,thisorderquantityisintherangeforthatprice),thenstop.Thisistheoptimallotsize.CalculateTCforthislotsize.Step2:IftheEOQisnotfeasible,calculatetheTCforthispriceandthesmallestquantityforthatprice.Step3:CalculatetheEOQforthenextlowestprice.Ifitisfeasible,stopandcalculatetheTCforthatquantityandprice.Step4:ComparetheTCforSteps2and3.ChoosethequantitycorrespondingtothelowestTC.Step5:IftheEOQinStep3isnotfeasible,repeatSteps2,3,and4untilafeasibleEOQisfound.27All-UnitQuantityDiscounts:ExampleCost/Unit$3$2.96$2.92OrderQuantity5,00010,000OrderQuantity5,00010,000TotalMaterialCost28All-UnitQuantityDiscount:ExampleOrderquantity UnitPrice0-5000 $3.005001-10000 $2.96Over10000 $2.92q0=0,q1=5000,q2=10000C0=$3.00,C1=$2.96,C2=$2.92D=120000units/year,S=$100/lot,h=0.229All-UnitQuantityDiscount:ExampleStep1:CalculateQ2*=Sqrt[(2DS)/hC2]=Sqrt[(2)(120000)(100)/(0.2)(2.92)]=6410Notfeasible(6410<10001)CalculateTC2usingC2=$2.92andq2=10001TC2=(120000/10001)(100)+(10001/2)(0.2)(2.92)+(120000)(2.92)=$354,520Step2:CalculateQ1*=Sqrt[(2DS)/hC1]=Sqrt[(2)(120000)(100)/(0.2)(2.96)]=6367Feasible(5000<6367<10000)StopTC1=(120000/6367)(100)+(6367/2)(0.2)(2.96)+(120000)(2.96)=$358,969TC2<TC1

TheoptimalorderquantityQ*isq2=1000130All-UnitQuantityDiscountsSupposefixedordercostwerereducedto$4Withoutdiscount,Q*wouldbereducedto1265unitsWithdiscount,optimallotsizewouldstillbe10001unitsWhatistheeffectofsuchadiscountschedule?RetailersareencouragedtoincreasethesizeoftheirordersAverageinventory(cycleinventory)inthesupplychainisincreasedAverageflowtimeisincreasedIsanall-unitquantitydiscountanadvantageinthesupplychain?31利用數(shù)量折扣獲取規(guī)模經濟全部單位數(shù)量折扣qi<Qi<qi+1TCi＝（R/Qi）S+(Qi/2)+RCi32月需求量1000訂購成本100儲存成本20%訂購數(shù)量單價0-500035001-100002.9610000-2.92Drugonline33解：q0＝0，q1＝5000，q2＝10000C0＝3，C1＝2.96，C2＝2.92R=120000,S=100,h＝0.2Q0*=(2RS/hC)1/2

＝(2*120000*100/3*0.2)1/2

＝6324q1＝5000時，TC0=(R/q1)S+(q1/2)hC1+RC1=120000/5000*100+5000/2*0.2*2.96+120000*2.96＝359080Q1*=(2RS/hC)1/2

＝(2*12000*100/2.96*0.2)1/2

＝6367Q1*=6367時，TC1=(R/Q1)S+(Q1/2)hC+RC1=358969Q2*=(2RS/hC)1/2

＝(2*12000*100/3*0.2)1/2

＝6410q2=10000時，TC2=(R/q2)S+(q1/2)hC+RC1=35452034WhyQuantityDiscounts?CoordinationinthesupplychainCommodityproductsProductswithdemandcurve2-parttariffsVolumediscounts35Coordinationfor

CommodityProductsD=120,000bottles/yearSR=$100,hR=0.2,CR=$3SS=$250,hS=0.2,CS=$2Retailer’soptimallotsize=6,324bottlesRetailercost=$3,795;Suppliercost=$6,009Supplychaincost=$9,80436Coordinationfor

CommodityProductsWhatcanthesupplierdotodecreasesupplychaincosts?Coordinatedlotsize:9,165;Retailercost=$4,059;Suppliercost=$5,106;Supplychaincost=$9,165EffectivepricingschemesAll-unitquantitydiscount$3forlotsbelow9,165$2.9978forlotsof9,165ormorePasssomefixedcosttoretailer(enoughthatheraisesordersizefrom6,324to9,165)37QuantityDiscountsWhen

FirmHasMarketPowerNoinventoryrelatedcostsDemandcurve 360,000-60,000pWhataretheoptimalpricesandprofitsinthefollowingsituations?ThetwostagescoordinatethepricingdecisionPrice=$4,Profit=$240,000,Demand=120,000ThetwostagesmakethepricingdecisionindependentlyPrice=$5,Profit=$180,000,Demand=60,00038Two-PartTariffsand

VolumeDiscountsDesignatwo-parttariffthatachievesthecoordinatedsolutionDesignavolumediscountschemethatachievesthecoordinatedsolutionImpactofinventorycostsPassonsomefixedcostswithabovepricing39LessonsfromDiscountingSchemesLotsizebaseddiscountsincreaselotsizeandcycleinventoryinthesupplychainLotsizebaseddiscountsarejustifiedtoachievecoordinationforcommodityproductsVolumebaseddiscountswithsomefixedcostpassedontoretaileraremoreeffectiveingeneralVolumebaseddiscountsarebetteroverrollinghorizon40為什么采取數(shù)量折扣的策略1）供應鏈的協(xié)調如果供應鏈是縱向一體化，且每一階段運作均考慮供應鏈總體利潤，則可以實現(xiàn)協(xié)調運作，但是，產權的差異，導致各階段追求各自利益最大化。41A、對最終產品數(shù)量折扣——案例Vitaminco：R＝10000，S＝100，h＝20％，Cm＝3；計算出Q*＝6324，TC＝3795制造商：S＝250，C0＝2，h＝20％。制造商訂購成本＝120000/6324*250＝4744制造商年存儲成本＝6324/2*2*0.2＝1265總成本＝4744+1265＝6009供應鏈總成本＝6009+3795＝9804如果Q*＝9165，則：供應鏈總成本＝120000/9165*100+9165/2*3*0.2+120000/9165*250+9165/2*2*0.2＝4059+5106＝9165結論：制造商會通過數(shù)量折扣讓度部分利益，實現(xiàn)總體利益最大化42引論：以批量折扣為基礎的折扣降低了供應鏈總成本，但增加了零售商采購批量，增加了供應鏈循環(huán)庫存。如果制造商致力于降低其建設成本和訂購成本時，規(guī)模折扣就會發(fā)生改變。但實際情況卻是，生產運作部門降低固定成本，營銷部門提供數(shù)量折扣？?。ㄋ伎迹?3B、對公司有市場控制權的產品實行數(shù)量折扣案例：某藥品市場需求曲線q=360000-60000p。制造商成本c0=2，批發(fā)價c1=4。r銷=（360000-60000p）p-（360000-60000p）c1r`=360000-120000p+60000c1=0P=5q=60000r銷=60000r制=120000r供=18000整合后：p=4q=120000r供=18000044協(xié)調方法：第一種、兩部分定價：制造商先索取全部利潤作為前期特許經營費，再將產品以成本出售第二種、以總量為基礎的數(shù)量折扣Q<12000,p=4；Q>12000,p=3.5注意：零售商在期末加大采購，即曲棍球現(xiàn)象。對策：將總量折扣建立在滾動水平基礎上（以過去12周或者90天銷售量為基礎）452）利用差別定價使供應鏈利潤最大化顧客剩余廠商收益需求曲線供給曲線46Short-TermDiscounting:

TradePromotionsTradepromotionsarepricediscountsforalimitedperiodoftime(alsomayrequirespecificactionsfromretailers,suchasdisplays,advertising,etc.)Keygoalsforpromotionsfromamanufacturer’sperspective:Induceretailerstousepricediscounts,displays,advertisingtoincreasesalesShiftinventoryfromthemanufacturertotheretailerandcustomerDefendabrandagainstcompetitionGoalsarenotalwaysachievedbyatradepromotionWhatistheimpactonthebehavioroftheretailerandontheperformanceofthesupplychain?Retailerhastwoprimaryoptionsinresponsetoapromotion:PassthroughsomeorallofthepromotiontocustomerstospursalesPurchaseingreaterquantityduringpromotionperiodtotakeadvantageoftemporarypricereduction,butpassthroughverylittleofsavingstocustomers47ShortTermDiscountingQ*:NormalorderquantityC:Normalunitcostd:ShorttermdiscountD:Annualdemandh:Costofholding$1peryearQd:ShorttermorderquantityForwardbuy=Qd-Q*48ShortTermDiscounts:

ForwardBuyingNormalordersize,Q*=6,324bottlesNormalcost,C=$3perbottleDiscountpertube,d=$0.15Annualdemand,D=120,000Holdingcost,h=0.2Qd=Forwardbuy=49PromotionPassThrough

toConsumersDemandcurveatretailer:300,000-60,000pNormalsupplierprice,CR=$3.00Optimalretailprice=$4.00Customerdemand=60,000Promotiondiscount=$0.15Optimalretailprice=$3.925Customerdemand=64,500Retaileronlypassesthroughhalfthepromotiondiscountanddemandincreasesbyonly7.5%50TradePromotionsWhenamanufactureroffersapromotion,thegoalforthemanufactureristotakeactions(countermeasures)todiscourageforwardbuyinginthesupplychainCountermeasuresEDLPScanbasedpromotionsCustomercoupons51短期折扣：商業(yè)促銷制造商目的：引導零售商通過價格折扣、展示或者廣告宣傳刺激銷售；制造商庫存轉移；品牌競爭經銷商選擇：將一部分或者全部促銷優(yōu)惠讓度給消費者，刺激銷售；只是讓度一小部分，大批購進，緩慢銷售。52折扣價格下的最優(yōu)訂購數(shù)量：假設：折扣僅提供一次；Qd是Q*的倍數(shù)；零售商不將優(yōu)惠讓度給顧客。Qd＝dR/（C-d）h+CQ*/(C-d)超前采購量＝Qd-Q*如果零售商知道下一個促銷時間，設為Q1，則會選擇Q1和Qd的最小值。53案例：DO公司R=120000,CM=3,h＝0.2，Q*=6324,d＝0.15，求零售商訂購數(shù)量？

Qd＝dR/（C-d）h+CQ*/(C-d)＝0.15*120000/（3-0.15）0.2+3*6324/（3-0.15）＝38236循環(huán)庫存＝19118平均周轉時間＝38236/2*1