Page 169 - DCAP601_SIMULATION_AND_MODELING

Unit 9: Simulation of a PERT Network (I)

Basic Stipulations Notes

Basic Vocabulary of the PERT Diagram:
1. Activity – part of the project signify by an arrow or line
2. Best Estimate(B) – earliest completion time
3. Critical path(CP) – the most time consuming path through the diagram with no slack time
4. Earliest Start Time(EST) – earliest probable time for an activity to begin
5. Network – the project shown graphically
6. Most likely estimate(M) – length of time probably needed
7. Expected Time(ET) – the average duration time
8. Event – represents the start or finish of one or more events (shown as a circle, square, or
other symbol)
9. Latest Start Time(LST) – latest time an activity can begin and still be completed before the
next activity
10. Slack Time – latest start time minus earliest start time for an activity
11. Worst estimate(W) – negative time estimate

Basic Rule

1. All the preceding activities must be completed previous to the project can begin.
2. The arrows represent the logical precedence of the project.

Procedure for Development

1. Recognize all activities and relationships among them.
2. Sketch the diagram.
3. Estimate the times for each activity, or node, in the diagram .
4. Conclude the critical path.
5. Evaluate the diagram for milestones and target dates in the overall project.

Example of Activity Network Diagram: A project is composed of a set of actions or tasks which
typically have some kind of interdependency. For example, before an axle can be turned, it must
first be designed, the metal must be purchased, etc. This type of complex system is much easier
to appreciate through the use of diagrams than through textual description, as actual
interconnections between tasks can be shown. You can draw the activity network diagram
easily with Edraw software.

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