PROJECT NETWORK DIAGRAM
PREPARED BY :
NOR AZAH BINTI AZIZ
KOLEJ MATRIKULASI TEKNIKAL KEDAH
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OBJECTIVES
•
•
•
•
Define Network Diagram
Purpose of Network Diagram
Method : Activity On the Node (AON)
Identify ES, EF, LS, LF using Forward Pass
Calculation and Backward Pass calculation
• Identify Critical Path
• Identify Slack Time
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INTRODUCTION
• A PND is a pictorial representation of the
sequence in which the project work can be
done.
• The activities and its duration are the basic
building blocks needed to construct a graphic
picture of the project
• Its provide
- the earliest time at which work can be begin on
every activity that makes up the project
- the earliest expected completion date of the
project
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IMPORTANCE OF ND
• ND can be used for ;
i) Planning : gives a clear graphical picture of
the relationship between project activities
ii) Implementation : when updating the project
file with activity status and estimate to
completion data, the ND is then
automatically updated and can be printed
or viewed
iii) control : while updated ND will retain the
status of all activities, the best graphical
report and controlling project work will be
Gantt Chart
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METHODS
I) THE ACTIVITY ON THE NODE ( AON)
•
•
•
•
Basic unit of analysis in ND is the activity
Each activity is represented by a rectangle
( activity node)
Arrows represent the
predecessor/successor relationship
between activities
Every activity in the project will have its
own activity node ( each rectangle)
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METHODS
I) THE ACTIVITY ON THE NODE ( AON)
B
D
A
F
C
E
PDM format of a project network diagram
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METHODS
I) THE ACTIVITY ON THE NODE ( AON)
Dependencies
A dependency is simply a relationship that exists
between pairs of activities
4 types of activity dependencies
A
B
FS : A finishes, B start
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METHODS
I) THE ACTIVITY ON THE NODE ( AON)
Dependencies
A
FF : A finishes, B finish
B
A
A
SS : A start, B start
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METHODS
I) THE ACTIVITY ON THE NODE ( AON)
Dependencies
A
B
SF : A starts, B finish
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I) THE ACTIVITY ON THE NODE ( AON)
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I) THE ACTIVITY ON THE NODE ( AON)
Creating an initial project network schedule
B
Start
3
D
5
A 1
F
C 2
E
3
End
2
Forward Pass calculations
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EST, LST, EFT, LFT
• CPM uses the following times for an activity
EST
LST
EFT
LFT
- Early Start time is the earliest time the activity
can begin
- Late Start Time is the latest time the activity can begin
- still allow the project to be completed on time
- Early Finish Time is the latest time the activity can end
- Late Finish Time is the latest time the activity can end
- still allow the project to be completed on time
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Forward Pass calculations
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Backward Pass calculations
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CRITICAL PATH METHOD (CPM)
• An effective way to analyze complex projects
• Represent the critical set of activities to complete a project
• Help to focus on essential activities which are critical to run
the project
• Allows the project manager to concentrate on important
activities
• CP is the longest path on ND and the most important part
• Any delays on the CP will lead to delay of the project
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CRITICAL PATH METHOD (CPM)
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FLOAT
• Also known as slack, total float and path float
• Is computed for each task by subtracting EFT from
the LFT
( @ the early start from the late start)
• Is the amount of time the task can slip without
delaying the project finish date.
• Free float is the amount of time a task can slip
without delaying the early start of any task
that immediately follows it.
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Slack Time calculations
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EXAMPLE
1. TABLE 1 shows the activities and the durations required to complete a
construction project, including the precursor activity.
Refering to the TABLE 1:
i) draw the project network diagram.
ii) state the activities on the critical path.
iii) calculate the minimum duration of the project.
Activity
Precursor
Duration (week)
A
-
7
B
A
6
C
A
5
D
A,B
4
E
B,C
3
F
D,E
2
19
13 4 17
D
13 0 17
0
0
START
0
0
0 7 7
A
0 0 7
7 6 13
B
7 0 13
7 5 12
ES D EF
activity
C
17 2 19
14 3 16
E
F
17 0 19
19 19
END
19 19
14 1 17
9 2 14
LS F LF
project network diagram
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