财务管理与财务分析运营管理课件.ppt

财务管理与财务分析运营管理课件,Inventory Systems for Independent Demand,Basic fixed order quantity systemConstant DemandUncertain demandBasic fixed time period systemNewsvendor modelSupply chain contract,4,Purposes of Inventory,1.To maintain independence of operations2.To meet variation in product demand3.To allow flexibility in production scheduling4.To provide a safeguard for variation in raw material delivery time5.To take advantage of economic purchase-order size,Inventory Costs,Holding(or carrying)costsSetup(or production change)costsOrdering costsShortage costs.,Classifying Independent Demand Systems,Fixed-Order QuantityThe reorder point Fixed-Time Period Hybrid Systems-Both Together-Order Periodically unless we reach the reorder point.,Inventory Systems for Independent Demand,Basic fixed order quantity systemConstant DemandUncertain demandBasic fixed time period systemNewsvendor modelSupply chain contract,OPERATIONS MANAGEMENT CLASS,Fixed-Order Quantity ModelsEconomic Order Quantity(EOQ):Assumptions,Demand for the product is constant and uniform throughout the periodLead time(delivery time of the order)is constantPrice per unit of product is constant.,Fixed-Order Quantity Models Economic Order Quantity:Assumptions(contd),Inventory holding cost is based on average inventory.Ordering or setup costs are constant.All demands for the product will be satisfied(No lost sales are allowed).,EOQ:A SIMPLE MODEL,Book Store Mug SalesDemand is constant,at 20 units a weekFixed order cost of$12,no lead timeHolding cost of 25%of inventory value annuallyMugs cost$1.00,sell for$5.00QuestionHow many,when to order,EOQ Model-Basic Fixed-Order Quantity Model,R=Reorder point=L*d Q=Economic order quantityL=Lead timed=Demand per Unit of Time,Numberof unitson hand,.,Cost Minimization Goal,Annual Ordering Costs,HoldingCosts,QOPT,Order Quantity(Q),COST,Annual Cost ofItems(DC),Total Cost,.,TAHC=H*(Q/2)TAOC=S*D/QTAC=TAHC+TAOC,S:cost of placing an order or setup cost,Basic Fixed-Order Quantity Model,TC Total annual costD DemandCCost per unitQ Order quantitySCost of placing an order or setup costRReorder pointLLead timeHAnnual holding and storage cost per unit of inventory,.,Deriving the EOQ-Calculus Method,Using calculus,we take the derivative of the total cost function and set the derivative(slope)equal to zero.,Recognizing TAHC=TAOC at OptimalTAHC=H*Q/2TAOC=S*D/QH*Q/2=S*D/Q,Solving for Q Yields:,Deriving the EOQ-Graphical Method,EOQ:OPTIMAL ORDER QUANTITY,Optimal Quantity=So for our problem,the optimal quantity is 316,(2*Demand*Setup Cost)/holding cost,EOQ Example,Annual Demand=1,000 unitsDays per year considered in average daily demand=365Cost to place an order=$10Holding cost per unit per year=$2.50Lead time=7 daysCost per unit=$15,Determine the economic order quantity and the reorder point.,.,Solution,Why do we round up?,.,In-Class Exercise,Annual Demand=10,000 unitsDays per year considered in average daily demand=365Cost to place an order=$10Holding cost per unit per year=10%of cost per unitLead time=10 daysCost per unit=$15,Determine the economic order quantity and the reorder point.,Note:(Tag hidden-slide icon to project solution).,Solution,.,Inventory Systems for Independent Demand,The definition and purpose of inventoryInventory costsBasic fixed order quantity systemConstant DemandUncertain demandCustomer Service-Achieving Percent Fill RatesBasic fixed time period systemNewsvendor model,OPERATIONS MANAGEMENT CLASS,Achieving High Customer Service,Add buffer stockOrder earlier Achieve desired customer service Percent fill rate=.99=9,900/10,000 are supplied directly from stock,Fixed Order Quantity System Under Uncertainty,Adding Safety Stock to Order Earlier,Fixed Order Quantity System Under Uncertainty,R=Reorder pointQ=Economic order quantityL=Lead timeL=Standard Error of Estimate During LeadtimeB=Buffer stock set to achieve P,B=Add buffer stock in case demand during leadtime expected d*L,STRATEGIC IMPORTANCE OF%FILL(P),P is set by top management P is strategic performance measure P=99.8 is becoming more commonHow do we control inventories to achieve P?,THE VARIANCE LAW,If X and Y are two independent random variables and Z=X+Y then E(Z)=E(X)+E(Y)and Z2=X2+Y2 What if Z=X-Y?.,Forecasting demand during lead time,MEAN DEMAND=d*LWhere L is length of lead timeAssume L=3,d=standard deviation in forecasting of demandL=standard deviation during leadtime.L=dThis Assumes Demand is Normally Independently DistributedThis Allows the Use of the E(Z)Concept,STATISTICAL INVENTORY CONTROLSCIENTIFIC INVENTORY CONTROL,Set the reorder point to yield desired percent fill(P)R=dL+ZL=Mean+Buffer Stock where R=Reorder Point dL=Mean Demand During Leadtime L=Standard Error of Forecast During LT Z=Value Determined to Achieve P,(1-P)D=Number of Units Short Per YearE(Z)=Units short each order cycle when L is 1.Number of Units Short Per Year=E(Z)*L*D/Q Equating Both E(Z)*L*D/Q=(1-P)D rearranging:E(Z)=(1-P)Q/L,Determining the Value of Z:Service level E(Z)Z,Inventory Systems for Independent Demand,The definition and purpose of inventoryInventory costsBasic fixed order quantity systemConstant DemandUncertain demandCustomer Service-Achieving Percent Fill RatesBasic fixed time period systemNewsvendor model,OPERATIONS MANAGEMENT CLASS,Inventory Management Using Marginal,One-Period ModelClassically Called the Newsvendor ProblemItems Ordered Only Too many then only salvage valueToo little lost customers,Newsvendor:Exercise,An equipment repair firm wishes to order enough spare parts to keep machines running throughout a trade show.The repairman sell the parts at$95 each if needed for a repair.He pays$70 for the cost of each part.If all the parts are not needed,they may be returned to the supplier for a credit of$50 each.The demand for the parts is estimated.,Newsvendor:Exercise,Number ofFrequency parts of Need00.1010.1520.2030.3040.2050.05,Newsvendor:Exercise,Number ofFrequency parts of NeedCPn00.100.1010.150.2520.200.4530.300.7540.200.9550.051.00REV-COST/(REV-SLV)=0.555Optimum order quantity is 3,Marginal profit(MP)=marginal loss(ML),Stove until MP(IF SOLD)=ML(IF NOT)Under conditions of uncertainty E(MP)=E(ML)P1(MP)=P2(ML)where P1 Prob of Selling and P2 is Prob of Not SellingNow P2=1-P1P1(MP)=(1-P1)ML,yields:P1=ML/(MP+ML),that is,stock items until the probability of selling the last item equals P1.,NEWSVENDOR PROBLEM IS COMMON,NEWSPAPERSGREETING CARDSCALENDARSTAX GUIDESOVERBOOKING AIRLINE SEATSOTHER APPLICATIONS?,Revenue Sharing Contract:Blockbuster case,Before:Wholesale price of a type is$60,renting price is$3After:Wholesale price of a type is$9,renting price is still$3,but the retailer needs to share 50%revenue with the supplier,