Activity Network Diagram and application.ppt
- 2. • Network: – A network is an arrow diagram denoting all the activities of a project taking into account the technological sequence of the activities. – Represented by Activity –On – Arrow Diagram or simply an Arrow diagram.
- 3. Project A project is usually a one time activity with a well defined set of desired end results.
- 4. Some Basic Definitions • Activity - Activity is a sub-task of a project - It usually consumes resources - An activity is represented by an arrow with a node at the beginning and a node at the end indicating the start and finish of the activity.
- 5. Some Basic Definitions Event: - Represented by a circle - Start and /or finish of an activity - Preferably called node
- 6. Some Basic Definitions Predecessor Activity: Activities that must be completed immediately prior to the start of another activity are called predecessor activities. Successor Activity: Activities that cannot be started until one or more of other activities are completed. Concurrent or Parallel Activities: Activities which can be accomplished concurrently are known as concurrent or parallel activities.
- 7. Some Basic Definitions Dummy Activity: An activity which does not consume any kind of resource but merely serves the purpose of indicating the predecessor or successor relationship clearly in network is called as a dummy activity. Merge Event: when more than one activity joins an event, such an event is known as merge event Burst Event: When more than one activity leaves an event, such an event is known as burst event Merge and Burst Event:
- 8. Some Basic Definitions • Identity Dummies – when two or more parallel independent activities have the same head and tail events, the identity of the activities, as given by the event numbers, could be lost.
- 9. Some Important Tips for Drawing A Good Network • Avoid crossing of arrows • Use straight arrows • Do not attempt to represent the duration of an activity by its arrow length • Use arrows from left to right • Use dummies where necessary • The network has only one entry point, called the start event.
- 10. Errors in a Network • Looping • Dangling