This document discusses network diagrams, PERT (Project Evaluation and Review Technique), and CPM (Critical Path Method) for project scheduling. It provides the history and applications of PERT/CPM, the steps involved, and compares PERT and CPM. Key points covered include defining a project, developing activity relationships, drawing the network diagram, estimating activity times, determining the critical path, and using the network to plan and control the project. Advantages and disadvantages of PERT/CPM techniques are also presented.

1. Network Diagrams,
PERT & CPM, Practice
with MS Project
Lecture (6 & 7)
Mr. Mubashir Ali
Lecturer(Dept. of Computer Science)
dr.mubashirali1@gmail.com

2. PROJECT
Combination of
interrelated activities
Executed in logical
sequence
Accomplishment of a
desired objective

3. “A project is a temporary
effort undertaken to create a
"unique" product or service”
Plan your work first…..then work
your plan

4. HISTORY OF PERT/CPM
Developed by
the US Navy
for the
planning and
control of the
Polaris missile
program
The emphasis
was on
completing
the program in
the shortest
possible time.
PERT
Developed by
Du Pont to
solve project
scheduling
problems
The emphasis
was on the
trade-off
between the
cost of the
project and its
overall
completion
time
CPM

5. Why PERT/CPM?
 Prediction of deliverables
 Planning resource requirements
 Controlling resource allocation
 Internal program review
 External program review
 Performance evaluation
 Uniform wide acceptance

6. APPLICATIONS OF PERT/CPM
TECHNIQUES
SPM
• Construction of a Dam or Canal
• Construction of a building or highway
SPM
• Maintenance of aircrafts
• Space Flights
SPM
• Designing a Prototype of a Machine
• Development of Supersonic Planes

7. Steps in PERT/CPM
4. CONTROLLING
3. ALLOCATION OF RESOURCES
2. SCHEDULING
1. PLANNING

8. Framework for PERT and CPM
 Define the Project. The Project should have only a
single start activity and a single finish activity.
 Develop the relationships among the activities.
 Draw the "Network" connecting all the activities.
 Assign time and/or cost estimates to each activity
 Compute the critical path.
 Use the Network to help plan, schedule, monitor and
control the project.

9. CPM - Critical Path Method
Drafting the design of
Program or Project
Evaluation of drafted
Program or Project
Review of evaluated
Program or Project

10. PERT - Project Evaluation &
Review Techniques
To analyze and represent the tasks
involved in completing a given project
Accommodates the variation in event
completion time
Event-oriented technique rather than
start- and completion-oriented
Commonly used in conjunction with
the critical path method

11. Basic Terms In Network
Analysis
Activity
Event
Constraints
Network Diagram
Critical Path

12. Network Diagram
Concepts
 Activity
 Precedence relationship
 Successor
 Event

13. Guidelines for network
diagram
1. Before an activity can begin, its
preceding activities must be completed.
2. Arrows indicate logical precedence.
3. Flow of the diagram is from left to right.
4. Arrows should not intersect.
5. Dangling should be avoided.

14. APPRAOCHES FOR NETWORK
DIAGRAM
ACTIVITY ON ARC(AOA):
 Uses arcs to represent activities and nodes
to represent events.
 It is Event Oriented.
1 876
54
3
2

15. DUMMY ACTIVITY
AOA approach requires the addition of a Dummy Activity to
clarify the precedence relationships between the two activities.
It is a zero time activity and consumes no resources.
Dummy Activity is used in two situations:
1. When two or more activities start and end at the same nodes.
1 3
2

16. 2) When two or more activities share the same
precedence activity but not all the precedence
are shared.
1 53
6
7
2 4
Continued..

17. Uses nodes to represent activities and arcs indicate
precedence relationships between them.
It is Activity Oriented.
ACTIVITY ON NODE(AON):

18. ESTIMATING TIME OF COMPLETION
Planning the schedule of the project
Time estimates include:
1) Total time for completion.
2) ES- Earliest start time: the earliest time at which
the activity can start given that its precedent activities
must be completed first.
3) EF-Earliest finish time: equals to the earliest start
time for the activity plus the time required to complete
the activity.
4) LF- Latest finish time: the latest time in which the
activity can be completed without delaying the project.
5) LS- Latest start time: equal to the latest finish time
minus the time required to complete the activity.

19. 6) FORWARD PASS: The early start and early finish times
are calculated by moving forward through the network and
considering the predecessor activities Considers maximum
7) BACKWARD PASS: The latest start and finish times are
calculated by moving backward through the network
Considers minimum.
8) SLACK TIME: Slack time for an activity is the difference
between its earliest and latest start time or between the
earliest and latest finish time. Critical path is the path of
activities having zero Slack time.
Continued..

20. Errors in Network Construction
 Dangling
3 4 6 8
5
7
Dangling

21. Looping
4 5 9
7
6
8
Looping

22. Redundancy
5
6
7Redundancy

23. Comparison Between PERT & CPM
Both are Quantitative Techniques
of Network Analysis
Both are used as tools for Decision
Making
Both involve drawing & analysis of
Network Diagram on various scores

24. Difference Between PERT & CPM
Probabilistic Model
Non-repetitive Jobs like
planning & scheduling of
programmes
Results calculated on basis of
Events
Related with activities of
uncertain time
Deterministic Model
Repetitive Jobs like residential
construction
Results calculated on basis of
activities
Related with activities of Well
Known time
PERT CPM

25. Advantages of PERT/CPM
Reduction in cost
• Elimination of Risk in Complex activity
Flexibility
• Optimization of Resources
Reduction of Uncertainties

26. Disadvantages of PERT/CPM
Network charts tend to be large
Lack of a timeframe on most PERT/CPM charts makes
it harder to show status
When PERT/CPM charts become unwieldy, they are
no longer used to manage the project
Planning & Implementation required skillful personnel

27. References & Assignment
• Introduction to Operations Research 7th
Edition by Hillier & Lieberman (Chapter-10)
• Install MS-Project and build your Final Year
Project structure by using ‘SOW’ and ‘WBS’.
• For better understanding of MS-Project
working, follow any tutorial from YouTube.