Operation Research / CPM and PERT

Operation Research

Operation research means a mathematical technique or approach which based on past experience or hit & trial method and provides results.

Project Management

A project is a task which has a beginning and end points and constitute of various activities, which are interrelated and must be accomplished to achieve the objectives of the project. The salient features of a project are:

• A project has certain beginning and end points.
• Each project can be divided into a number of activities which will consume time and resources during their completion.
• A project is scheduled to be completed by a target date.

Network Construction 

A network is the graphical representation or arrow diagram which consists of different activities arranged in a logical sequence and maintaining the relationships among preceding and succeeding activities. Basic terms used in network construction

Activity: An activity is a part of a project, which consumes both time and resources. It is represented by an arrow connecting two points in a network diagram. The head of an arrow represents the start point and the tail of arrow represents its end point. An activity in the network can be represented by an alphabets and a number.

Event: An event represents the point from where any activity is to be started or any activity comes to end. Each event is represented by a circle in a network diagram. It does not consume any time or resource. Numbering of nodes is started with the node having all outgoing arrows and no incoming arrow and numbered as 1.

Dummy Activity: The activity which does not consume any time or resource called dummy activity. It is represented by dotted line and not represented by any alphabets.

Rules for drawing network diagram

Rule 1: Each activity is represented by one and only one arrow in the network.

Rule 2: No two activities can be identified by the same end events.

Rule 3: Precedence relationships among all activities must always be maintained.

Rule 4: Dummy activities can be used to maintain precedence relationships only when actually required. Their use should be minimized in the network diagram.

Rule 5: Looping among the activities must be avoided.

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