TABLE 21. Time and Workforce Requirements for a
Technical Project
Activity, Duration, Workers
Fig. 17 days required
0-1 4 3
1-2 7 5
2-4 10 9
2-3 3 9
3-4 2 12
4-8 3 4
1-5 8 6
5-6 3 10
6-8 4 8
5-7 2 6
7-8 1 7
Calculation Procedure:
- Compute the early and late event times
The results of these calculations, made in accordance with the previous calculation proce-
dure, are shown in Fig. 17.
- Identify the critical path
Since the critical path is the longest path through the network, Fig. 17 shows that this is O-
1-2-4-8. Note that the critical path sets a lower limit of 24 days on the duration of the
project. But the workforce limitations may lengthen the project beyond 24 days. Thus, the
objective will be to devise a schedule that fits noncritical activities into the 24-day period
while satisfying the workforce availability.
- Schedule the project, assuming unlimited workforce
As a first trial, assume that unlimited workforce is available, and schedule each activity to
start at the earliest possible date. Construct the workforce-time diagram for this condi-
tion, as shown in Fig. 18#. Study of the diagram shows that this schedule is unsatisfactory
because the workforce requirements exceed the available workers on days 12 to 15, inclu-
sive.
- Schedule the project with the latest possible start
Assume unlimited workforce again, and schedule each activity to start at the latest possi-
ble date. Construct the corresponding workforce-time diagram, Fig. 18&. Study of the dia-
gram shows that this schedule is also unsatisfactory, but it is an improvement over the
schedule instep 3.
Although both these schedules are unsatisfactory, they are useful because their work-
force-time diagrams reveal the boundaries of each activity or chain of activities based on
a project duration of 24 days. For example, the chain 5-7-8 may start at any time between
days 12 and 21, Fig. 18. This information is not explicitly supplied by the network, since
the late event time for event 5 is determined by the chain 5-6-8.
- Shift noncritical activities to obtain a suitable schedule
Using the allowable workforce limits, shift noncritical activities such that the project can
be completed in 24 days using the available workers.
