Take the Earliest Expected Time of Occurrence of the Start Event as
Procudure To Find The Earliest Expected Time Of
An Event
Step 1
Take the Earliest Expected Time of Occurrence of
the Start Event as zero.
Step 2
For an event other than the Start Event, find out
all paths in the network which connect the Start node with the node
representing the event under consideration.
Step 3
In the “Forward Pass” (i.e., movement in the
network from left to right), find out the sum of the time durations of the
activities in each path identified in Step 2.
Step 4.
The path with the longest time in Step 3 gives the
Earliest Expected Time of Occurrence of the event
Working Rule for finding the earliest expected time
of an event:
For an event under consideration, locate all the
predecessor events and identify their earliest expected times. With the
earliest expected time of each event, add the time duration of the activity
connecting that event to the event under consideration. The maximum among all
these values gives the Earliest Expected Time of Occurrence of the event. Procudure To Find The
Latest Allowable Time Of An Event
We consider the “Backward Pass” (i.e., movement in
the network from right to left). The latest allowable time of occurrence of the End
Node must be the time of completion of the project. Therefore it shall be equal
to the time of the critical path of the project. Step 1 Identify the latest allowable
time of occurrence of the End Node. Step 2 For an event other than the End Event, find out all
paths in the network which connect the End node with the node representing the
event under consideration. Step 3 In the “Backward Pass” (i.e., movement in the
network from right to left), subtract the time durations of the activities
along each such path. Step 4 The Latest Allowable Time of Occurrence of the
event is determined by the path with the longest time in Step 3. In other
words, the smallest value of time obtained in Step 3 gives the Latest Allowable
Time of Occurrence of the event. Working Rule for finding the
latest allowable time of an event: For an event under consideration, locate all the
successor events and identify their latest allowable times. From the latest
allowable time of each successor event, subtract the time duration of the
activity that begins with the event under consideration. The minimum among all
these values gives the Latest Allowable Time of Occurrence of
the event.
Tags : Operations Management - Network Problems
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