CPM - path method critical
In 1957, DuPont join developed project to raise management method aimed the Philipe will challenge products factories of chemicals for maintenance, in restarting then once plants that ended was maintenance. The complexity given the process, they have developed he Method (CPM) criticize path for the management of such projects.
CPM following offer benefits them:
• Provides one graphical display of the project.
• Allows of predict time to complete Customized project him.
• What shows to maintain essential activities are the annex and which are not.
Models CPM them activities and events such as a project of a network. Depicted are as activities of the network and nodes indicate Post the events which will start or end of activities are like bows in Reps or lines between nodes them. Here is one example of a CPM network diagram:
CPM diagram
Stages of CPM planning project
1 Individual specify activities them.
Two. Determine the sequence of these activities.
Three. Draw one network diagram.
April. Estimated time of each activity the order.
May. Critical path identify (longest trail network through him)
June. Updating will diagram during the project CPM.
1. Clarify them individual activities
From the structure of distribution of work, you can make a list of all project activities. This list serve basis can the addition of sequence of time and information in later stages.
Two. Determine the sequence of activities
Dependent of the some completion activities of others. The list of the immediate predecessors of activity is useful for each build him CPM network diagram.
Three. Draw you network diagram
Once activities them were and their sequencing defined, we can draw diagram of the CPM him. Developed CMP was originally as an activity on node (AON) network, but some projects prefer planners specify arcs activities them.
April. Estimate the time of end of activity
The time to complete each Customized activity can be considered passed by using the experience of the people or the well informed estimates. Deterministic CPM which is a model do not reflect in variation of time execution, estimate time of number is then used one for an activity.
May. Identify the critical path
The critical path is the path of longer network through him. The Importance of the critical path is which is activities them top can be are delayed delay without him. In reason of its impact on the whole of the project, the analysis of the path critical is one important aspect of the planning of the project.
Determine the critical path can be by the identified four following parameters activity for each:
• ES - start earlier: soon the most during the activity which can start previous gives that fulfilled activities must be first.
• EF - finish early, equal to the first hour of the activity start of Customised more time for activity complete.
• LF - last hour Ending: the last time where the activity can be delayed without delaying accomplished project him.
• LS - last start time, equal to the last hour less time to finish complete necessary for the activity.
The soft for an activity is the time between her first and last hour of beginning or between first and the last time end. Soft is the amount of time that an activity can be after delayed are more earlier departure define sooner or without project delay him.
The critical path is the path through which will network in none of the margin, it is - to-say, the path and which = EF = LF LS for all activities in the path. A delay critical delay path in the draft him. Similarly, akin project to accelerate him, it is necessary of reduce the time for Total Customized activities in the critical path.
June. CPM chart update
You project progresses, order them task time real will known, and network diagram can be updated to include akin this information. Again way critical emerge and can be made can structural changes in the network if they project requirements change.
Limitations of CPM
Developed CPM was for complex projects, but with enough common uncertainty minimum achievement at the time of the project. For routine projects less there is more uncertainty achievement at the time, and this uncertainty limit usefulness of deterministic CPM model. CPM in the alternative one is the planning of PERTproject model, which allows one of od range specify each activity for.
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