# PERT and CPM – 18 Critical Path – Slacks – Floats Part 4 of 8 – Es and Ef of Events - Videos

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#Operations Research_OR
#Network Analysis
#PERT and CPM
#Project Management
#PERT Chart
#Network Diagram
#Earliest Start
#Earliest Finish
#Forward Pass Method
#Backward Pass Method

Draw Network Diagram and trace the Critical Path. Also Also find Total, Interfering, Free and Independent floats/slacks :
Activity
Name: A B C D E F G H I J K
Activity
Node: 1-2 1-3 1-4 2-5 3-5 3-6 3-7 4-6 5-7 6-8 7-8
Duration
(days): 2 7 8 3 6 10 4 6 2 5 6

Earliest Start Time (Es):
Earliest Start time of an activity is the earliest time an activity can can possibly start without affecting the project completion.

Earliest Finish Time (Ef):
Earliest Finish Time of an activity is the earliest time an activity can possibly finish without affecting the project completion.

Forward Pass Method:
In Forward Pass Method, calculation of Es and Ef begin from the initial event 1, proceed through the events in an increasing order of even numbers and end at the final event, we can say N. At each event we calculate the earliest occurrence time of the event and Earliest Start (Es) and Earliest Finish (Ef) time for each activity that begins at that event. When calculations end at the final event N, the earliest occurrence time gives the possible completion time of the entire project.

Backward Pass Method – Latest Start Time (Ls) – Latest Finish Time (Lf)

Latest Start Time (Ls):
Latest Start time of an activity is the latest possible time an activity can start without delaying the project completion.

Latest Finish Time (Lf):
Latest Finish Time of an activity is the latest time an activity must finish without delaying the project completion.

Backward Pass Method:
In Backward Pass Method, calculation of Ls and Lf begin from the final event N, proceed through the events in an decreasing order of even numbers and end at the initial event . At each event we calculate the latest occurrence time of the event and Latest Start (Ls) and Latest Finish (Lf) time for each activity that is terminating at that event and this procedure continues till the initial event.

Critical Path:
The longest network path, which consists of a set of activities that connects the “network start event” to the “network end event” is called “Critical Path”. The length of the CP determines the minimum duration in which the project can be completed.

Critical or Bottleneck Activities:
All the activities on the CP are called critical or bottleneck activities. The delay in the completion of one or more of these activities will cause delay in the completion time of the project. If, somehow, any of these activity is completed before the expected time, the entire project can also be completed before the expected time. So, such activities require special attention.

OR, Operations Management, Math, Network Analysis, PERT, CPM, Project Management, PERT Chart, Network Diagram, Earliest Start, Earliest Finish, Es, Ef, Forward Pass, Backward Pass, Slack, Float, Critical Path, Activity, Event, Merge Event, Burst Event, Predecessor, Successor, Statistics, OM, Operations Management, MBA, MCA, CA, CS, CWA, BBA BCA, BCom, MCom, GRE, GMAT, Grade 11, Grade 12, Class 11, Class 12, IAS, CAIIB, FIII, IBPS, BANK PO, UPSC, CPA, CMA

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