Transcript 投影片 1 - 朝陽科技大學

Chapter 7
~ HOMEWORK ~
By: Prof. Y. Peter Chiu
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.
a. Determine the MPS for the computers.
b. Determine the planned order release for the motherboards
assuming a lot-for-lot scheduling rule.
c. Determine the scheduling for outside orders for the disk
drives.
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.
a. 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?
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
Net requirements 100
11
100
12
40
13
40
14
15
16
17
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.
a. Determine the planned order release for component A.
b. Determine the planned order release for component B.
c. Determine the planned order release for component C.
(Hint: Note that C is
required for both A and B.)
7-9
An end item has the product structure given in Figure 7-7.
a. Write the product structure diagram as an indented bill-of-materials list.
b. 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.
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
a.Silver-Meal.
b.Least unit cost.
c. Part period balancing.
d.Which lot-sizing method resulted in the lowest
cost for the 12 periods?
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 the EOQ formula?
b. Determine the lot sizes using the Silver-Meal heuristic.
c. Determine the lot sizes using the Least unit cost heuristic.
d. Determine the lot sizes using Part 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.
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.
a. Enumerate all the exact requirements policies,
compute the holding and setup costs for each, and
find the optimal production plan.
b. Solve the problem by backward dynamic programming.
The End