Problem 1: The following data were obtained from a study of the times required to conduct a consumer test panel study:
|
|
Crash Schedule
|
Normal Schedule
|
|
Activity
|
Time
|
Cost
|
Time
|
Cost
|
|
1-2
|
3
|
$6
|
5
|
$4
|
|
1-3
|
1
|
$5
|
5
|
$3
|
|
2-4
|
5
|
$7
|
10
|
$4
|
|
3-4
|
2
|
$6
|
7
|
$4
|
|
2-6
|
2
|
$5
|
6
|
$3
|
|
4-6
|
5
|
$9
|
11
|
$6
|
|
4-5
|
4
|
$6
|
6
|
$3
|
|
6-7
|
1
|
$4
|
5
|
$2
|
|
5-7
|
1
|
$5
|
4
|
$2
|
Note: Costs are given in thousands of dollars, time in weeks
(a) Find the all-normal schedule and cost.
(b) Find the all-crash schedule and cost.
(c) Find the total cost required to expedite all activities from all-normal (see a) to all-crash (see b).
(d) Find the least-cost plan for the all-crash time schedule. Start from the all-crash problem (see b). Assume partial crashing.
Problem 2: The network for shooting a TV commercial as shown in the table has a fixed cost of $90 per day, but money can be saved by shortening the project duration. Find the least-cost schedule.
|
|
Normal
|
Crash
|
Cost Increase
|
|
Activity
|
Time
|
Time
|
(1st, 2nd, 3rd day)
|
|
1-2
|
7
|
4
|
$30, $50, $70
|
|
2-3
|
9
|
6
|
$40, $45, $65
|
|
1-3
|
12
|
10
|
$60, $60
|
|
2-4
|
11
|
9
|
$35, $60
|
|
3-4
|
3
|
3
|
-
|
Cost/Schedule Control System Criteria
1. Calculate cost schedule and variance.
2. Interpret the cost and schedule status of case 3, 10, 11, and 12.
|
Case
|
BCWS
|
ACWP
|
BCWP
|
Cost Variance
|
Schedule Variance |
|
1
|
800
|
800
|
800
|
|
|
|
2
|
800
|
600
|
400
|
|
|
|
3
|
800
|
400
|
600
|
|
|
|
4
|
800
|
600
|
600
|
|
|
|
5
|
800
|
800
|
600
|
|
|
|
6
|
800
|
800
|
1000
|
|
|
|
7
|
800
|
1000
|
1000
|
|
|
|
S
|
800
|
600
|
800
|
|
|
|
9
|
800
|
1000
|
800
|
|
|
|
10
|
800
|
1000
|
600
|
|
|
|
11
|
800
|
600
|
1000
|
|
|
|
12
|
800
|
1200
|
1000
|
|
|
|
13
|
800
|
1100
|
1200
|
|
|
Note: Cost variance = BCWP – ACWP (negative values = overruns)
Schedule variance = BCWP – BCWS (negative values = slippage)
Imhotep, project manager for building a pyramid, is asked by the Pharaoh: "How much of the pyramid is completed?" Imhotep knows that the pyramid will use 1 million stone blocks. He also knows that 700,000 blocks have been used to date. He tells the Pharaoh that the pyramid is 70 percent complete. What is the problem with this assessment?