《供应链习题课》word版.doc

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1、1. Moon Micro is a small manufacturer of servers that currently builds all of its product in Santa Clara, California. As the market for servers has grown dramatically, the Santa Clara plant has reached capacity of 10,000 servers per year. Moon is considering two options to increase its capacity. The

2、 first option is to add 10,000 units of capacity to the Santa Clara plant at an annualized fixed cost of $10,000,000 plus $500 labor per server. The second option is to have Molectron, an independent assembler, manufacture servers for Moon at a cost of $2,000 for each server (excluding raw materials

3、 cost), raw materials cost $8,000 per server, and Moon sells each server for $15,000.Moon must make this decision for a two-year time horizon. During each year, demand for Moon servers has an 80 percent chance of increasing 50 percent from the year before and a 20 percent chance of remaining the sam

4、e as the year before. Molectrons prices may change as well. They are fixed for the first year but have a 50 percent chance of increasing 20 percent in the second year and a 50 percent chance of remaining where they are.Using a decision tree to determine whether Moon should add capacity to its Santa

5、Clara plant or if it should outsource to Molectron. What are some other factors that would affect this decision that we have not discussed.Assume that a discount factor is 10 percent. 注意：Moon已有设备产能为10,000，对两种方案都是一样提供该产能，所以比较增量需求利润即可。Option AYear 2Revenue2=(20,000-10,000)*15,000*0.64+(15,000-10,000)*

6、150,000*(0.16+0.16) +(10,000-10,000)*15,000*0.04Variable cost2 = (20,000-10,000)*500*0.64 +(15,000-10,000)*500*(0.16+0.16) +(10,000-10,000)*500*0.04Fixed cost2=10,000,000Total cost2= Variable cost2+ Total cost2Profit2 = Revenue2- Total cost2Year 1Revenue1=(15,000-10,000)*15,000*0.8+(10,000-10,000)*1

7、50,000*0.2Variable cost1=(15,000-10,000)*500*0.8+(10,000-10,000)*500*0.2Fixed cost1=10,000,000Total cost1= Variable cost1+ Total cost1Profit1 = Revenue1- Total cost1Base Year 0Profit0 =0Option BYear 2Revenue2=(22,500-10,000)*15,000*(0.32+0.32) +(15,000-10,000)*15,000*(0.08+0.08+0.08+0.08) +(10,000-1

8、0,000)*15,000*(0.02+0.02)Cost2 =(22,500-10,000)*(2000+8000) *0.32+(22,500-10,000)*(2400+8000) *0.32+(15,000-10,000)*(2000+8000)*(0.08+0.08)+(15,000-10,000)* (2400+8000)*(0.08+0.08) +(10,000-10,000)*(2000+8000)*0.02 +(10,000-10,000)* (2400+8000)*0.02Profit2 = Revenue2- Total Cost2同理可得Year 1 ,Year 0利润

9、，代入下式：比较NPVA, NPVB大者为最优方案！2. Weekly sales of Hot Pizza are as follows:WeekDemand ($)WeekDemand ($)WeekDemand($)11085969112211661191010231187961192412481021291Estimate demand for the next four weeks using a four-week moving average and simple exponential smoothing with =0.1. Evaluate the MAD, MAPE, M

10、SE, bias, and TS in each case. Which of the two methods do you prefer? Why?Refer to excel!3. Harley Davidson has its assembly plant in Milwaukee and its motorcycle assembly plant in Pennsylvania. Engines are transported between the two plants using trucks, with each trip costing $1000. The motorcycl

11、e plant assembles and sells 300 motorcycles each day. Each engine costs $500, and Harley incurs a holding cost of 20 percent per year. How many engines should Harley load onto each truck? What is the cycle inventory of engines at Harley?Solution:The economic order quantity is given by . In this prob

12、lem:D = 109,500 (i.e., 300 units/day multiplied by 365 days/year) S = $1000/orderH = hC =0.2*500 = $100/unit/yearSo, the EOQ value is 1480 units So the total yearly cost is $147,986.The cycle inventory value is EOQ/2 = 1480/2 =7404. Prefab, a furniture manufacturer, uses 20,000 square feet of plywoo

13、d per month. Their trucking company charges Prefab $400 per shipment, independent of the quantity purchased. The manufacturer offers an all unit quantity discount with a price of $1 per square foot for orders under 20,000 square feet, $0.98 per square foot for orders between 20,000 square feet and 4

14、0,000 square feet, and $0.96 per square foot for orders larger than 40,000 square feet. Prefab incurs a holding cost of 20 percent per year. What is the optimal lot size for Prefab? What is the annual cost of such a policy? What is the cycle inventory of plywood at Prefab? How does it compare with t

15、he cycle inventory if the manufacturer does not offer a quantity discount but sells all plywood at $0.96 per square foot?SolutionPricing:Min QtyMax QtyPrice per sq. ft. 019,999 $ 1.00 20,00040,000 $ 0.98 40,000 $ 0.96 (1) For, price = $1.00 per unitQ1= EOQ = Since Q1 19,999We select Q1= 20,000 (brea

16、k point) and evaluate the corresponding total cost, which includes purchase cost + holding cost + order costTotal Cost1= = = $ 241,960(2) For, price = $0.98 per unitQ2= EOQ = Total Cost2 = = = $241,334(3) For, price = $0.96 per unitQ3= EOQ = We select Q3= 40,000 (break point) and evaluate the corres

17、ponding total cost, which includes purchase cost + holding cost + order costTotal Cost3 = = =$236,640Total Cost3 Total Cost2 Total Cost 1So, the optimal value of Q* = 40000 and the total cost is $236,640The cycle inventory is Q*/2 = 40000/2 = 20000(b) If the manufacturer did not offer a quantity dis

18、count but sold all plywood at $0.96 per square foot then Q = 31,623 and the total cost is $ 233,4365. Weekly demand for Motorola cell phones at a Best Buy store is normally distributed, with a mean of 300 and a standard deviation of 200. Motorola takes two weeks to supply a Best Buy order. Best Buy

19、is targeting a CSL of 95% and monitors its inventory continuously. How much safety inventory of cell phones should Best Buy carry? What should its ROP be.SolutionDL = LD = 2*300 = 600 = = = 283ss = FS-1 (CSL) sL = FS-1 (0.95) 283 = 465 (where, FS-1 (0.95) = NORMSINV (0.95)=1.6431)ROP = DL + ss = 600

20、 + 465 = 10656. Assume that the Best Buy store in Exercise 1. The store manager has decided to review inventory every three weeks. Assuming a periodic review replenishment policy, evaluate the safety inventory that the store should carry to provide a CSL 95%. Evaluate the OUL for such a policy.Solut

21、ionDL = (T+L) D = (2+3)*300 = 1500 = = = 447ss = FS-1 (CSL) sL = FS-1 (0.95) 447 = 736 (where, FS-1 (0.95) = NORMSINV (0.95) =1.6431)OUL = D(T+L) + ss = 1500 + 736 = 2236Supply chain, cycle inventory, safety inventory, replenishment policy, continuous review, periodic review, product fill rate, cycl

22、e service level, economies of scale, the fixed ordering cost, holding cost, material cost, total cost, optimal lot size, average flow time, quantity discount, supply chain strategy, supply chain planning, supply chain operation, cycle view of supply chain processes, push/pull view of supply chain pr

23、ocesses, supply chain performance, strategic fit, cost-responsiveness efficient frontier, competitive strategy, level of product availability, distribution network, facility location, capacity allocation, decision tree, demand forecasting, time series forecasting methods, simple exponential smoothing, forecast error, mean squared error, aggregate planning, subcontracting, time flexibility strategy, chase strategy, marginal unit quantity discount, forward buy.