Formation of Network Diagram And

8/6/2019 Formation of Network Diagram And

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FORMATION OF NETWORKDIAGRAM AND

CPM

Presentation by : Vandana TibbaniSourabh Harwani

Mamta Singh

Shrijika Jain

MBA(FA) SEM III


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NETWORK DIAGRAM

Network analysis is the general name given to certain specific

techniques which can be used for the planning, management

and control of projects

The aim of planning is to develop a sequence of activities ofthe project , so that project completion time and cost are

properly balanced and excessive demand of key resources is

avoided.

PERT AND CPM are techniques used for planning scheduling

and controlling of large complex projects .


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SITUATIONS IN WHICH PERT

AND CPM is used The project consist of well defined collection of

activities or tasks.

The activities can be started and terminatedindependently of each other .

The activities are ordered so that they can be

performed in a technological sequence.

Thus a precedence relationships exist whichpreclude the start of certain activities until others

are completed.


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Why PERT/CPM?

Prediction of deliverables

Planning resource requirements

Controlling resource allocation

Internal program review

External program review

Performance evaluation Uniform wide acceptance


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Project Network Use of nodes and arrows

Arrows An arrow leads from tail to head directionally

Indicate ACTIVITY, a time consuming effort that is required toperform a part of the work.

Nodes A node is represented by a circle

- Indicate EVENT, a point in time where one or more activities startand/or finish.

5

Activity

A task or a certain amount of work required in the project

Requires time to complete

Represented by an arrow

Dummy Activity

Indicates only precedence relationships

Does not require any time of effort


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Event Signals the beginning or ending of an activity

Designates a point in time

Represented by a circle (node) Network

Shows the sequential relationships among activitiesusing nodes and arrows

6

Activity-on-node (AON)

nodes represent activities, and arrows show precedence

relationships

Activity-on-arrow (AOA)

arrows represent activities and nodes are events for points intime

Project Network


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Basic Logic Patterns for Arrow Diagrams

i jActivity

Event

(a) Basic Activity


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Basic Logic Patterns for Arrow Diagrams (cont.)Basic Logic Patterns for Arrow Diagrams (cont.)

2A

(b) Independent Activities

4 10B

12

3A

6B

9

(c) Dependent Activities


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RULES :

Events are identified by numbers successors

event no. > preceding nos.

No duplication of events numbers in anetwork.

A network should have only one initial & one

terminal node.

The length & bearing of arrow are of no

significance.


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Basic Logic Patterns for Arrow Diagrams (cont.)Basic Logic Patterns for Arrow Diagrams (cont.)

2

A

(d) A Merge

4

6B

8

(e) A Burst

C

Activity C depends upon the completion of both Activities A & B

8

A

6

2

B

4C

Activities B and C both depend upon the completion of Activity A


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Basic Logic Patterns for Arrow Diagrams (cont.)

(f) A Cross

20

18C

16 D

14

A12

B

Activities C and D both depend upon the completion of Activities A and B


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The use of dummy to maintain unique numbering of activitiesThe use of dummy to maintain unique numbering of activities

10

8C

6D

4

A2

B

10

8C

6

4

A2

Divide node to correct

(a) Incorrect Representation

(b) Correct Representation

D5

B

Dummy


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The use of dummy to maintain unique numbering of activities (cont.)The use of dummy to maintain unique numbering of activities (cont.)

4 10

4 10

11

A

B

A

B

Divide node to correct

Dummy




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Removal ofRedundant Dummies

A

A

A

A

B

B

B

B

C C

Original Diagram Diagram after removal of

redundant dummies

(a)

(b)


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Removal of Redundant Dummies (cont.)

A

A

A

A

C

C

B

C

B B

Original Diagram Diagram after removal of

redundant dummies

(c)

(d)

B E

C

E

E E


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Combining Beginning and Ending Nodes (cont.)Combining Beginning and Ending Nodes (cont.)

2 8 12A E

4 14

6 10 16C F

B

2

10

8

16




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AOA Project Network for House

darla/smbs/vit 17

3

2 0

1

3

1 1

11 2 4 6 7

3

5

Lay foundation

Design house

and obtain

financing

Order and

receive

materials

Dummy

Finishwork

Select

carpet

Select

paint

Buildhouse

AON Project Network for House

1

3

2

2

4

3

3

1 5

1

6

1

7

1Start

Design house and

obtain financing

Order and receivematerials Select paint

Select carpet

Lay foundations Build house

Finish work


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EXAMPLE :A work consist of projects consist of twelve labeled A through L .Upon

being asked to specify the order in which the jobs had been done ,themanager laid down following steps:

And the precedence relationship between them is as follows :

Activity Immediate Predecessor

A -

B -C -

D A,B

E B

F B

G C,F

H B

I E,H

J E.H

K C,D,F ,I

l K


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AN EXAMPLE

1

4

5

A

C

6 9

E

3 7 8

B

F

2

H

I

D

G

J

K

L

Activi

ty

Immediate

Predecess

or

A -

B -

C -

D A,B

E B

F B

G C,F

H B

I E,HJ E.H

K C,D,F ,I

l K

Tasks are Arrows

Events are Circles

Critical Tasks are Thick Arrows

Dummy Tasks are Dashed Arrows


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CPM calculation

Path

A connected sequence of activities leading from

the starting event to the ending event

Critical Path

The longest path (time); determines the project

duration Critical Activities

All of the activities that make up the critical path

20


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Generate Initial CPM Diagram

Must strictly enforce all prerequisite relationships.

Number of events is initially unknown

Critical path is initially unknown

Iterative Process

Try to minimize number of Dummy Tasks


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So according to diagram seen

the critical paths will be :Activity Immediate

Predecessor

Time(DAYS)

A - 6

B - 4

C -10

D A,B 1

E B 1

F B 3

G C,F 14

H B 6

I E,H 9

J E.H 2

K C,D,F ,I 7

l K 5

PATHS LENGTH

1-3-7-8-9 19

1-2-3-7-8-9 17

1-2-4-5-7-8-9 19

1-2-5-7-8-9 24*critical

1-2-5-9 19

1-2-4-5-9 14

1-2-6-7-8-9 19

1-2-6-9 211-6-7-8-9 22

1-6-9 24*critical


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Forward Pass Earliest Start Time (ES)

earliest time an activity can start

ES = maximum EF of immediate predecessors Earliest finish time (EF)

earliest time an activity can finish earliest start time plus activity time

EF= ES + t

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Latest Start Time (LS)

Latest time an activity can start without delaying critical path time

LS= LF - t

Latest finish time (LF)

latest time an activity can be completed without delaying critical path time

LS = minimum LS of immediate predecessors

Backward Pass


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CPM analysis Draw the CPM network

Analyze the paths through the network

Determine the float for each activity

Compute the activitys float

float = LS - ES = LF - EF

Float is the maximum amount of time that this activity can

be delay in its completion before it becomes a critical

activity, i.e., delays completion of the project

Find the critical path is that the sequence of activities and

events where there is no slack i.e.. Zero slack Longest path through a network

Find the project duration is minimum project completion time

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EXAMPLE :FOR FLOATATION

1

5

7

6

8

4

3

2

F,10F,10

A,2A,2 E,6E,6

B,7B,7

C,8C,8

D,3D,3

G,4G,4

H,6H,6

J,5J,5

K,6K,6

I,2I,2


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EXAMPLE :ES- EF TIME

1

5

7

6

8

4

3

2

F,10F,10

A,2A,2

E,6E,6

B,7B,7

C,8C,8

D,3D,3

G,4G,4

H,6H,6

J,5J,5

K,6K,6

I,2I,2

20

0 7

52

137

80 148

177

117

1513

2217

2115

Projects EF =Projects EF = 2222


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EXAMPLE :CRITICAL PATH

1

5

7

6

8

4

3

2

F,10F,10

A,2A,2

E,6E,6

B,7B,7

C,8C,8

D,3D,3

G,4G,4

H,6H,6

J,5J,5

K,6K,6

I,2I,2


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DETERMINATION OF CRITICAL PATH

RULES :

1) If an activity the ES times equals LF time at the head

of the arrow and if the ES time equals the LF Time at

the tail of the arrow ,the activity is possibly a critical

activity path

1) The e difference between the ES time at the head of

the arrow and the ES time at the tail of the arrow is

equal to the duration of the activity


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We have seen that critical activities should have float

has 0 which is determined by total float whichrepresents amount of time by which it can be delayed

without delaying the project completion date

TOTAL FLOAT = LF-EF or LS ES or

LF- ES duration of activityEXAMPLE in activity 2-5 it is 14-2-3= 9 days

INTERFERING FLOAT :the part of total float which

causes a reduction in the float of the successoractivates.

EX- for activity 2-5 the the lf=14 while 5-7 is ES=13 the

interfing float is 14-13 =1


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FREE FLOAT : total float which can be used without affecting

the float of succeeding activitiesFor example: activity 2-5 total float is 9 days the free float is 8( LS

of succeeding activity 13 Ef of the activity 5)

FREE FLOAT= Total float head slack

Head slack can be defined as the difference between the earliestand latest event times (14-13=1;9-1=8)

Independent float=

ES for following activity LF for preceding activity duration of

present activity the amount of float which can be used without

affecting either head or the tail events

For example for activity 2-5 13-11-3=-1

It is taken as zero as negative not considered


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PROJECT MANAGEMENT:

THE 3 PHASES AND 10 STEPS

Step 1: Project Decomposition

Step 2: Specification of the Precedence Relationships

Step 3: Estimation of the Activity DurationsPhase I: Project Formulation

Step 4: Construction of the Project Network

Step 5: Computation of Each ActivitysEarliest Start

Time and Earliest Finish Time

Step 6: Computation of Each Activitys Latest Start Timeand Latest Finish Time

Step 7: Computation of Each Activitys Total SlackandIdentification of the Critical Path

Phase II: Planning & Scheduling

Step 8: Scheduling the ActivitiesStep 9: Monitoring of the Projects Activities

Phase III: Monitoring & Replanning Step 10: Replanning of the Remaining Portion of theProject


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THANK U

Documents

Formation of Network Diagram And