Project
A project is a series of activities directed to accomplishment of a desired objective.
Basically, CPM (Critical Path Method) and PERT (Programme Evaluation Review Technique) are project management techniques, which have been created out of the need of Western industrial and military establishments to plan, schedule and control complex projects.CPM was developed by DuPont for chemical plants, whereas PERT was developed by U.S. Navy for Polaris missile un 1950's.
PERT - Project Evaluation & Review Techniques
In PERT activities are shown as a network of precedence relationships using activity-on-arrow network construction. It is used in project management for non-repetitive jobs like research and development , where the time and cost estimates tend to be quite uncertain. This technique uses probabilistic time estimates.
Network of Events and Ativities.
Events or nodes are represented by circle with node number in it. They indicate a point in time where one or more activities start and/or finish. Activity, or a task is represented by an arrow from starting node to ending node. Activity indicates time required to complete that part of work segment.The entire project should have only a single start activity and a single finish activity.
Each event has two important times associated with it :
- Earliest time , TE , which is a calendar time when a event can occur when all the predecessor events are completed at the earliest possible times
- Latest time , TL , which is the latest time the event can occur with out delaying the subsequent events and completion of project.
Difference between the latest time and the earliest time of an event is the slack time for that event . Slack =TL-TE
Positive slack : Slack is the amount of time an event can be delayed without delaying the project completion.
Critical Path is the sequence of activities from start event to end event where there is no “slack” i.e.. Zero slack. It is the longest through a network and indicates minimum project completion time.
1. Define the Project and all of it's significant activities or tasks.
2. Develop the relationships among the activities.
3. Decide which activities must precede and which must follow others.
4. Draw the "Network" connecting all the activities.
5. Each Activity should have unique event numbers.
6. Dummy arrows are used where required to avoid giving the same numbering to two activities.
7. Assign time and/or cost estimates to each activity.
8. Compute the longest time path through the network. This is called the critical path.
A project is a series of activities directed to accomplishment of a desired objective.
Basically, CPM (Critical Path Method) and PERT (Programme Evaluation Review Technique) are project management techniques, which have been created out of the need of Western industrial and military establishments to plan, schedule and control complex projects.CPM was developed by DuPont for chemical plants, whereas PERT was developed by U.S. Navy for Polaris missile un 1950's.
PERT - Project Evaluation & Review Techniques
In PERT activities are shown as a network of precedence relationships using activity-on-arrow network construction. It is used in project management for non-repetitive jobs like research and development , where the time and cost estimates tend to be quite uncertain. This technique uses probabilistic time estimates.
Network of Events and Ativities.
Events or nodes are represented by circle with node number in it. They indicate a point in time where one or more activities start and/or finish. Activity, or a task is represented by an arrow from starting node to ending node. Activity indicates time required to complete that part of work segment.The entire project should have only a single start activity and a single finish activity.
Each event has two important times associated with it :
- Earliest time , TE , which is a calendar time when a event can occur when all the predecessor events are completed at the earliest possible times
- Latest time , TL , which is the latest time the event can occur with out delaying the subsequent events and completion of project.
Difference between the latest time and the earliest time of an event is the slack time for that event . Slack =TL-TE
Positive slack : Slack is the amount of time an event can be delayed without delaying the project completion.
Critical Path is the sequence of activities from start event to end event where there is no “slack” i.e.. Zero slack. It is the longest through a network and indicates minimum project completion time.
1. Define the Project and all of it's significant activities or tasks.
2. Develop the relationships among the activities.
3. Decide which activities must precede and which must follow others.
4. Draw the "Network" connecting all the activities.
5. Each Activity should have unique event numbers.
6. Dummy arrows are used where required to avoid giving the same numbering to two activities.
7. Assign time and/or cost estimates to each activity.
8. Compute the longest time path through the network. This is called the critical path.
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