PROJECT I
Discuss the limitations of PERT/CPM methodology, as applied to actual projects.
PERT-CPM, like the other tools considered thus far, is not a "Swiss Army knife." It won't solve all problems. Its usefulness is limited by the nature of the project, and the state of the manager's knowledge about what the project will involve.
Here are some questions that need to be answered before deciding whether to use PERT-CPM. The list is far from exhaustive.
To what extent can the project be broken down into discrete tasks? How should that breakdown happen? Example: When building a house, is tiling the floors and the shower stalls one job, or two?
To what extent are the tasks sequentially dependent? Example: Again, when building a house, the kitchen exhaust fan should installed before the attic is insulated; but if need be, the insulation can be swept aside and the fan installed later.
How accurately are the task durations known?
How accurately are the task costs known?
Are the start date and the deadline "set in stone," or merely aspirational? ("It would be nice if we could move in before Christmas, but... well, you know, whatever.")
We're going to discuss projects we're familiar with, either because we took part in them, or observed them closely. Was PERT-CPM used? Should it have been? COULD it have been? Why or why not?
Expectations
Describe a project you're familiar with. Analyze it carefully in light of the material covered in this module. List specific factors that made it more or less suitable for the PERT-CPM planning process. Was some version of PERT-CPM used? Should it have been? Why or why not?
PROJECT II
PERT/CPM
You're expected to provide references and citations. It's recommended you use the sources listed in the Module. This Module contains all the information neede
Case Assignment
The Galaxy project consists of 8 interdependent tasks, labeled A through H. You've consulted experts, and have determined an optimistic, likely and pessimistic completion time (in days) for each of the tasks. The dependencies, and the times, are listed below.
|
Task
|
Precursor(s)
|
Optimistic
|
Likely
|
Pessimistic
|
|
A
|
(start)
|
2
|
6
|
9
|
|
B
|
A
|
18
|
19
|
20
|
|
C
|
A
|
10
|
12
|
14
|
|
D
|
A
|
12
|
18
|
24
|
|
E
|
(start)
|
13
|
14
|
16
|
|
F
|
B, C, D
|
8
|
12
|
16
|
|
G
|
D, E
|
6
|
8
|
10
|
|
H
|
F, G
|
17
|
20
|
21
|
|
(end)
|
H
|
|
|
|
1. Draw a path diagram for the project.
2. Calculate the expected length of each task. Fill in the following worksheet
|
Task
|
Optimistic (O)
|
Likely (L)
|
Pessimistic (P)
|
Expected Task
|
|
A
|
2
|
6
|
9
|
|
|
B
|
18
|
19
|
20
|
|
|
C
|
10
|
12
|
14
|
|
|
D
|
12
|
18
|
24
|
|
|
E
|
13
|
14
|
16
|
|
|
F
|
8
|
12
|
16
|
|
|
G
|
6
|
8
|
10
|
|
|
H
|
17
|
20
|
21
|
|
3. Use the following worksheet to determine the lengths of all possible paths. Determine the critical path. What is its length?
The Mojo Project consists of 14 interrelated tasks, A through N. Their estimated normal completion times, normal costs, crash times and crash costs are given below. (Times in weeks; costs in thousands of dollars.)
|
Task
|
Predecessors
|
Normal Time
|
Normal Cost
|
Crash Time
|
Crash Cost
|
|
A
|
(start)
|
3
|
4
|
2
|
5
|
|
B
|
(start)
|
5
|
6
|
4
|
7
|
|
C
|
A
|
2
|
3
|
2
|
4
|
|
D
|
A
|
4
|
8
|
3
|
10
|
|
E
|
A
|
3
|
5
|
2
|
7
|
|
F
|
B
|
9
|
14
|
7
|
16
|
|
G
|
B
|
4
|
5
|
3
|
7
|
|
H
|
C, D
|
4
|
7
|
2
|
9
|
|
I
|
D
|
6
|
2
|
5
|
3
|
|
J
|
F
|
12
|
10
|
11
|
15
|
|
K
|
H
|
4
|
6
|
3
|
7
|
|
L
|
E, I, J
|
10
|
18
|
8
|
20
|
|
M
|
K, L
|
8
|
10
|
6
|
14
|
|
N
|
G
|
7
|
5
|
6
|
8
|
Use an online application (e.g., Sporkforge, 2014) to find the critical path, using the estimated normal times. Copy the output of the app into your upload as an image.
4. Which tasks are on the critical path?
5. What is the expected completion time of the project?
Instead of being finished in 4 weeks, task D takes 8 weeks.
6. Which (if any) tasks should be crashed, to make up the lost time? Why?
7. What is the additional cost of crashing the project?
Attachment:- Work mod 3.rar