供應(yīng)鏈管理(第11、12講)

Chapter7

ManagingEconomiesofScaleintheSupplyChain:CycleInventorySupplyChainManagement10-1OutlineRoleofCycleInventoryinaSupplyChainEconomiesofScaletoExploitFixedCostsEconomiesofScaletoExploitQuantityDiscountsShort-TermDiscounting:TradePromotionsEstimatingCycleInventory-RelatedCostsinPractice2第7章獲取供應(yīng)鏈規(guī)模經(jīng)濟的手段：循環(huán)庫存一、循環(huán)庫存在供應(yīng)鏈中的作用二、利用固定成本獲取規(guī)模經(jīng)濟三、利用數(shù)量折扣獲取規(guī)模經(jīng)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(guān)的費用3循環(huán)庫存產(chǎn)生原因——規(guī)模經(jīng)濟大批量生產(chǎn)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(yīng)鏈中的作用循環(huán)庫存指供應(yīng)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(shè)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(zhuǎn)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(jīng)濟單一產(chǎn)品批量規(guī)模Q（經(jīng)濟訂購批量）R＝產(chǎn)品年需求量S＝每次訂購固定成本C＝單位產(chǎn)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(dǎo)，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(zhuǎn)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(shè)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(zhuǎn)時間減少至1/2。Q*=年訂購次數(shù)＝R/Q*平均周轉(zhuǎn)時間＝Q*/2R結(jié)論：如果批量規(guī)模最佳，需求量增加，循環(huán)庫存周轉(zhuǎn)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(jīng)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(yīng)鏈的協(xié)調(diào)如果供應(yīng)鏈是縱向一體化，且每一階段運作均考慮供應(yīng)鏈總體利潤，則可以實現(xiàn)協(xié)調(diào)運作，但是，產(chǎn)權(quán)的差異，導(dǎo)致各階段追求各自利益最大化。41A、對最終產(chǎn)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(yīng)鏈總成本＝6009+3795＝9804如果Q*＝9165，則：供應(yīng)鏈總成本＝120000/9165*100+9165/2*3*0.2+120000/9165*250+9165/2*2*0.2＝4059+5106＝9165結(jié)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(chǔ)的折扣降低了供應(yīng)鏈總成本，但增加了零售商采購批量，增加了供應(yīng)鏈循環(huán)庫存。如果制造商致力于降低其建設(shè)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(chǎn)運作部門降低固定成本，營銷部門提供數(shù)量折扣？！（思考）43B、對公司有市場控制權(quán)的產(chǎn)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(diào)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(jīng)營費，再將產(chǎn)品以成本出售第二種、以總量為基礎(chǔ)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(chǔ)上（以過去12周或者90天銷售量為基礎(chǔ)）452）利用差別定價使供應(yīng)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(dǎo)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(zhuǎn)移；品牌競爭經(jīng)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(shè)：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(shè)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(zhuǎn)時間＝38236/2*1