James Walters manages at Athabasca UniversityProject Crash Example
Problem Data
It is required to calculate the crash schedule of the activities in order to reduce the time of the project, according to the following data:
- Number of Activities
- 5
- Target Time
- 8
- Time Unit
- Days
- Description
- James Walters manages at Athabasca UniversityWhat is the minimum cost of crashing by four days the following project that James Walters manages at Athabasca University?
- Table of Activities
Activity Immediate Predecessor(s) Normal Time (Days) Crash Time (Days) Normal Cost ($) Crash Cost ($) A 6 5 900 1000 B 8 6 300 400 C 4 3 500 600 D A 5 3 900 1200 E C 8 5 1000 1600
Solution
The following are the calculations and detailed graphs to obtain the critical path according to the data provided:
Step 1: Proyecto con tiempos normales
Network Diagram
The following chart shows the project activities, calculated with normal times:
The activities in red represent the critical path.
Normal Project Time Table
The following table presents the times for each activity. The critical path activities are highlighted in green.| Activity | Time | Early Start (ES) | Early Finish (EF) | Late Start (LS) | Late Finish (LF) | Slack (S) |
|---|---|---|---|---|---|---|
| A | 6 | 0 | 6 | 1 | 7 | 1 |
| B | 8 | 0 | 8 | 4 | 12 | 4 |
| C | 4 | 0 | 4 | 0 | 4 | 0 |
| D | 5 | 6 | 11 | 7 | 12 | 1 |
| E | 8 | 4 | 12 | 4 | 12 | 0 |
The critical path of the project is: C → E
The total time of the project (with normal times) is 12 Days
Since the project is required to be completed within 8 Days, some activities must be crashed to meet the goal. The procedure will be detailed in the next step.
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