12-20 Estimating activity time is not an easy task, especially if assumptions must be made. State whether each item identified below can be accounted…

12-20 Estimating activity time is not an easy task, especially if assumptions must be made.

State whether each item identified below can be accounted for in the construction of a

PERT/CPM network:

a. Consideration of weather conditions

b. Consideration of weekend activities

c. Unleveled manpower requirements

d. Checking of resource allocations

e. Variable crew size

f. Splitting (or interrupting) of activities

g. Assignment of unused resources

h. Accounting for project priorities

12-21 Scheduling departmental manpower for a project is a very difficult task, even if slack

time is available. Many managers would prefer to supply manpower at a constant rate rather

than continually shuffle people in and out of a project.

a. Using the information shown below, construct the PERT network, identify the critical

path, and determine the slack time for each node.

Activity, Weeks, Personnel Required (full Time)

A-B, 5, 3

A-C, 3, 3

B-D, 2, 4

B-E, 3, 5

C-E, 3, 5

D-F, 3, 5

E-F, 6, 3

b. The network you have just created is a departmental PERT chart. Construct a weekly

manpower plot assuming that all activities begin as early as possible. (Note: Overtime

cannot be used to shorten the activity time.)

c. The department manager wishes to assign eight people full-time for the duration of

the project. However, if an employee is no longer needed on the project, he can be

assigned elsewhere. Using the base of eight people, identify the standby (or idle) time

and the overtime periods.

d. Determine the standby and overtime costs, assuming that each employee is paid $300

per week and overtime is paid at time and a half. During standby time the employee

draws his full salary.

e. Repeat parts c and d and try to consider slack time in order to smooth out the manpower

curve. (Hint: Some activities should begin as early as possible, while others

begin as late as possible.) Identify the optimum manpower level so as to minimize the

standby and overtime costs. Assume all employees must work full-time.

f. Would your answer to parts d and e change if the employees must remain for the full

duration of the project, even if they are no longer required?