Page 150 - DCAP601_SIMULATION_AND_MODELING

Simulation and Modelling

Notes 2. Which are the critical activities or tasks in the project which could delay the entire
project if they were not completed on time?
3. Is the project on schedule, behind schedule or ahead of schedule?
4. If the project has to be finished earlier than planned, what is the best way to do this
at the least cost?

9.2.3 The Framework for PERT and CPM

Essentially, there are six steps which are common to both the techniques. The procedure is listed
below:
1. Define the Project and all of it’s important activities or tasks. The Project (made up of
several tasks) should have only a single start activity and a single finish activity.

2. Develop the relationships amongst the activities. Decide which activities must precede
and which must follow others.
3. Draw the “Network” connecting all the activities. Each Activity should have single event
numbers. Dummy arrows are used where required to avoid giving the same numbering
to two activities.

4. Allot time and/or cost estimates to each activity
5. Compute the longest time path during the network. This is called the critical path.
6. Use the Network to help plan, schedule, monitor and control the project.
The Key Concept used by CPM/PERT is that a petite set of activities, which make up the longest
path through the activity network control the entire project. If these “critical” activities could be
identified and assigned to dependable persons, management resources could be optimally used
by concentrating on the few activities which determine the fate of the entire project.
Non-critical activities can be replanned, rescheduled and resources for them can be reallocated
flexibly, without affecting the whole project.

Task Five useful questions to ask when preparing an activity network are:
1. Is this a Start Activity?
2. Is this a Finish Activity?
3. What Activity Precedes this?
4. What Activity Follows this?

5. What Activity is Concurrent with this?

Some activities are successively linked. The second activity can begin only after the first activity
is completed. In certain cases, the activities are concurrent, because they are independent of each
other and can start simultaneously. This is particularly the case in organisations which have
supervisory resources so that work can be delegated to various departments which will be
responsible for the activities and their completion as planned.
When work is delegated like this, the need for stable feedback and co-ordination becomes an
important senior management pre-occupation.

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