供应链物流管理中科院三chapter

1、8/6/2022S. Chopra/Availability1Determining Optimal Level of Availability in a Supply Chain8/6/2022S. Chopra/Availability2OutlineDetermining optimal level of product availabilitySingle order in a seasonContinuously stocked itemsOrdering under capacity constraints Levers to improve supply chain profit

2、abilityContracts8/6/2022S. Chopra/Availability3Mattel, Inc. & Toys “R” UsMattel was hurt last year by inventory cutbacks at Toys “R” Us, and officials are also eager to avoid a repeat of the 1998 Thanksgiving weekend. Mattel had expected to ship a lot of merchandise after the weekend, but retailers,

3、 wary of excess inventory, stopped ordering from Mattel. That led the company to report a $500 million sales shortfall in the last weeks of the year . For the crucial holiday selling season this year, Mattel said it will require retailers to place their full orders before Thanksgiving. And, for the

4、first time, the company will no longer take reorders in December, Ms. Barad said. This will enable Mattel to tailor production more closely to demand and avoid building inventory for orders that dont come.- Wall Street Journal, Feb. 18, 19998/6/2022S. Chopra/Availability4Key QuestionsHow much should

5、 Toys R Us order given demand uncertainty?How much should Mattel order?Will Mattels action help or hurt profitability?What actions can improve supply chain profitability?8/6/2022S. Chopra/Availability5How much to order? Parkas at L.L. Bean8/6/2022S. Chopra/Availability6Parkas at L.L. BeanCost per pa

6、rka = $45Sale price per parka = $100Discount price per parka = $50Holding and transportation cost = $10Profit from selling parka = $100-$45 = $55Cost of overstocking = $45+$10-$50 = $58/6/2022S. Chopra/Availability7Parkas at L.L. Bean Expected demand = 10 (00) parkasExpected profit from ordering 10

7、(00) parkas = $4998/6/2022S. Chopra/Availability8Parkas at L.L. Bean8/6/2022S. Chopra/Availability9Optimal level of servicer = sale price; s = outlet or salvage price; c = purchase priceCSL = Probability that demand will be at or below reorder pointAt optimal order size,Expected Marginal Benefit fro

8、m raising order size = (1-CSL*)(r - c) = Expected Marginal Cost = CSL*(c - s).(1-CSL*)Cu = CSL* Co,CSL* = Cu / (Cu + Co)8/6/2022S. Chopra/Availability10Order Quantity for a Single OrderCo = Cost of overstocking = $5Cu = Profit from sale =Cost of understocking = $55R* = Optimal order size8/6/2022S. C

9、hopra/Availability11Optimal Order QuantityOptimal Order Quantity = 130.9178/6/2022S. Chopra/Availability12How to Estimate Demand Distribution?Historical data: Time series forecastingDependent factors: Regression, causal forecastingExpert opinion: Buying committeeKey: Forecast must include estimated

10、demand and uncertainty (standard deviation) of demand8/6/2022S. Chopra/Availability13Continuously Stocked Items: Optimal Safety Inventory LevelsFor each order cycleBenefit of increasing safety stock by one unit = (1-CSL)CuCost of increasing safety stock by one unit = HQ*/RwhereCSL = probability of n

11、ot stocking out in a cycle with current level of safety stock = Cycle Service LevelH = cost of holding one unit for one yearR = Annual demandQ* = Economic order quantity 8/6/2022S. Chopra/Availability14Optimal Safety Inventory LevelsCSL = 1-HQ*/CuRR = 100 gallons/week; R= 20; H = $0.6/gal./yearL = 2

12、 weeks; Q = 400; ROP = 300.What is the imputed cost of stocking out?8/6/2022S. Chopra/Availability15Ordering Under Capacity ConstraintsAvailable Capacity = 1,500.8/6/2022S. Chopra/Availability16Assuming No Capacity Constraints8/6/2022S. Chopra/Availability17Ordering Under Capacity ConstraintsStep 0:

13、 Set Qi = 0 for all products i.Step 1: Compute the marginal contribution for all products i.Step 2: Increase Qj, for the product j with the largest marginal contribution, by 1.Step 3: If all the capacity is not used up and there is some product with a positive marginal contribution, return to Step 1

14、, else stop.8/6/2022S. Chopra/Availability18Marginal Contribution Calculations8/6/2022S. Chopra/Availability19Ordering Under Capacity ConstraintsAssume N products for i = 1, ., N, all produced using the same capacityTotal available capacity = Bri = sale price; si = outlet or salvage price; ci = purc

15、hase price. All are for product iMarginal contribution of raising order size of product i from Qi to Qi + 1 = (1-pi)(ri - ci) - pi(ri - si) where pi is the probability that demand for product i will be Qi or less.8/6/2022S. Chopra/Availability20Levers for Increasing Supply Chain ProfitabilityIncreas

16、e salvage value or decrease margin lost from stockoutImproved forecasting to lower uncertaintyQuick response to increase number of orders per seasonPostponement of product differentiationTailored sourcing8/6/2022S. Chopra/Availability21Impact of Improving ForecastsDemand: Normally distributed with a

17、 mean of R = 350 and standard deviation of R = 100Purchase price = $100Retail price = $250Disposal value = $85Holding cost for season = $5How many units should be ordered as R changes?8/6/2022S. Chopra/Availability22Impact of Improving Forecasts8/6/2022S. Chopra/Availability23Quick Response: Multipl

18、e Orders per SeasonOrdering shawls at a department storeSelling season = 14 weeksCost per handbag = $40Sale price = $150Disposal price = $30Holding cost = $2 per weekExpected weekly demand = 20SD of weekly demand = 158/6/2022S. Chopra/Availability24Impact of Quick Response8/6/2022S. Chopra/Availabil

19、ity25Forecast Improves for Second Order (SD=3 instead of 15)8/6/2022S. Chopra/Availability26Value of Postponement: BenettonFor each colorMean demand = 1,000; SD = 500For each garmentSale price = $50Salvage value = $10Production cost using option 1 (long lead time) = $20Production cost using option 1

20、 (greige thread) = $22What is the value of postponement?Expected profit increases from $94,576 to $98,0928/6/2022S. Chopra/Availability27Value of Postponement with Dominant ProductColor with dominant demand: Mean = 3,100, SD = 800Other three colors: Mean = 300, SD = 200Expected profit without postpo

21、nement = $102,205Expected profit with postponement = $99,8728/6/2022S. Chopra/Availability28Tailored Postponement: BenettonProduce Q1 units for each color using Option 1 and QA units (aggregate) using Option 2Results: Q1 = 800 QA = 1,550Profit = $104,6038/6/2022S. Chopra/Availability29Tailored Sourc

22、ingSourcing alternativesLow cost, long lead time supplierCost = $245, Lead time = 9 weeksHigh cost, short lead time supplierCost = $250, Lead time = 1 week8/6/2022S. Chopra/Availability30Tailored Sourcing Strategies8/6/2022S. Chopra/Availability31Tailored Sourcing: Multiple Sourcing Sites8/6/2022S.

23、Chopra/Availability32Dual Sourcing Strategies8/6/2022S. Chopra/Availability33Impact of Supply Chain Contracts on Profitability: Buyback ContractsBuybacks by publishersTech Fiber produces jacket at v = $10 and charges a wholesale price of c = $100. Ski Adventure sells jacket for p = $200. Unsold jackets have no salvage value. Should