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By: Prof. Y. Peter Chiu

Chapter 7 ~ HOMEWORK ~. By: Prof. Y. Peter Chiu. 7- 4.

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By: Prof. Y. Peter Chiu

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  1. Chapter 7 ~ HOMEWORK ~ By: Prof. Y. Peter Chiu

  2. 7- 4 • The Noname Computer Company builds a computer designated modeI ICU2. It imports the motherboard of the computer from Taiwan, but the company inserts the sockets for the chips and boards in its plant in Lubbock, Texas. Each computer require a total of 90 64K DRAM (dynamic random access memory) chips. Noname sells the computers with three add-in boards and two disk drives. The company purchases both the DRAM chips and the disk drives from an outside supplier. The product structure diagram for the ICU2 computer is given in Figure 7-6. • Suppose that the forecasted demands for the computer for weeks 6 to 11 are 220, 165, 180, 120, 75, 300. The starting inventory of assembled computers in week 6 will be 75, and the production manager anticipates returns of 30 in week 8 and 10 in week 10. • Determine the MPS for the computers. • Determine the planned order release for the motherboards assuming a lot-for-lot scheduling rule. • Determine the scheduling for outside orders for the disk drives.

  3. 7- 5 • For the previous problem, suppose that Noname has 23,000 DRAM chips in inventory. It anticipates receiving a lot of 3,000 chips in week 3 from another • firm that has gone out of business. At the current time, Noname purchases the chips from two vendors, A and B. A sells the chips for less, but will not fill • an order exceeding 10,000 chips per week. • If Noname has established a policy of inventorying as few chips as possible, what order should it be placing with vendors A and B over the next six weeks? • b. Noname has found that not all the DRAM chips purchased function properly. From past experience it estimates an 8 percent failure rate for the chips purchased from vendor A and a 4 percent failure rate for the chips purchased from vendor B. • What modification in the order scheduling would you recommend to compensate for this problem?

  4. 7-6 Consider the product structure diagram given in Figure 7-3. Assume that the MPS for the end item for weeks 10 through 17 is Week 10 11 12 13 14 15 16 17 Net requirements 100 100 40 40 100 200 200 200 • Assume that lot-for-lot scheduling is used throughout. Also assume • that there is no entering inventory in period 10 and no scheduling • receipts. • Determine the planned order release for component A. • Determine the planned order release for component B. • Determine the planned order release for component C. (Hint: Note that C is • required for both A and B.)

  5. 7-9 • An end item has the product structure given in Figure 7-7. • Write the product structure diagram as an indented bill-of-materials list. • Suppose that the MPS for the end item is Week 30 31 32 33 34 35 MPS 165 180 300 220 200 240 If production is scheduling on a lot-for-lot basis, find the planned order release for component F. c. Using the data in part (b), find the planned order release for component I. d. Using the data in part (b), find the planned order release for component H.

  6. 7-14 • A single inventory item is ordered from an outside supplier. The anticipated demand for this item over the next 12 months is 6, 12, 4, 8, 15, 25, 20, 5, 10, 20 5, 12. Current inventory of this item is 4, and ending inventory should be 8. Assume a holding cost of $1 per period and a setup cost of $40. • Determine the order policy for this item based on • Silver-Meal. • Least unit cost. • Part period balancing. • Which lot-sizing method resulted in the lowest cost for the 12 periods?

  7. 7-17 The time-phased net requirements for the base assembly in a table lamp over the next six weeks are: Week 1 2 3 4 5 6 Requirements 335 200 140 440 300 200 • The setup cost for the construction of the base assembly is $200, and the holding cost is $0.30 per assembly per week. • a. What lot sizing do you obtain from theEOQ formula? • b. Determine the lot sizes using theSilver-Meal heuristic. • Determine the lot sizes using theLeast unit cost heuristic. • d. Determine the lot sizes usingPart period balancing. • e. Compare the holding and setup costs obtained over the six periods using the policies found in parts (a) through (d) with the cost of a lot-for-lot police.

  8. 7-18 • Anticipated demands for a four-period planning horizon are 23, 86, 40, and 12. The setup cost is $300 and the holding cost is h=$3 per unit per period. • Enumerate all the exact requirements policies, compute the holding and setup costs for each, and find the optimal production plan. • Solve the problem by backward dynamic programming.

  9. The End

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