Unit II Project Planning Revised

8/11/2019 Unit II Project Planning Revised

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310-PROJECT MANAGEMENT

FACULTY:

Dr. CH. VENKATAIAH

B.Tech, MBA, PhDAssociate Professor (Operations, Quality & Project Management)


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PROJECT PLANNING

UNIT

II


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Dr. CH. VENKATAIAH

Associate Professor

310-Project Management 3

Project Planning

Resource Availability and/or LimitsDue date, late penalties, early completion

incentives

Budget

Activity Information

Identify all required activities

Estimate the resources required (time) to

complete each activity Immediate predecessor(s) to each activity needed

to create interrelationships


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Dr. CH. VENKATAIAH

Associate Professor


Project Scheduling and Control Techniques

Gantt Chart

Critical Path Method (CPM)

Program Evaluation and Review Technique

(PERT)


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Dr. CH. VENKATAIAH

Associate Professor


Graph or bar chart with a bar for each project activity that shows passage of time

Provides visual display of project schedule

Gantt Chart


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Dr. CH. VENKATAIAH

Associate Professor


History of CPM/PERT

Critical Path Method (CPM)

E I Du Pont de Nemours & Co. (1957) for construction ofnew chemical plant and maintenance shut-down

Deterministic task times

Activity-on-node network construction

Repetitive nature of jobs

Project Evaluation and Review Technique (PERT)

U S Navy (1958) for the POLARIS missile program

Multiple task time estimates (probabilistic nature)Activity-on-arrow network construction

Non-repetitive jobs (R & D work)


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Dr. CH. VENKATAIAH

Associate Professor


Project Network

Network analysis is the general name given to certain specific techniques which

can be used for the planning, management and control of projects

Use of nodes and arrowsArrows 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.

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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Dr. CH. VENKATAIAH

Associate Professor


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 activities using

nodes and arrows

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 in time

Project Network


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Dr. CH. VENKATAIAH

Associate Professor


AOA Project Network for House

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

Finish

work

Select

carpet

Select

paint

Build

house

AON Project Network for House

13

2

2

43

31 5

1

61

71Start

Design house

and obtain

financing

Order and receivematerials

Select paint

Select carpet

Lay foundations Build house

Finish work


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Dr. CH. VENKATAIAH

Associate Professor


Situations in network diagram

AB

C

A must finish before either B or C can start

A

B

C both A and B must finish before C can start

D

C

B

Aboth A and C must finish before either of B or D can

start

A

C

B

D

Dummy

A must finish before B can start

both A and C must finish before D can start


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Dr. CH. VENKATAIAH

Associate Professor


Concurrent Activities

2 3

Lay foundation

Order material

(a) Incorrect precedence

relationship

(b) Correct precedence

relationship

3

42

DummyLay

foundation

Order material

1

2 0


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Dr. CH. VENKATAIAH

Associate Professor

310-Project Management

Activity. It is a clearly defined project element, a job or atask which requires the consumption of resources includingtime. It is denoted by an arrow.

Event.An event describes the start or completion of anactivity. It is denoted by a numbered circle.

Path. A path is an unbroken chain of activities from theinitiating node to some other node, generally to the lastnode indicating the end or completion of the project.

Dummy Activity. A dummy activity is that activity which hasa logical function only and consumes no time or resources.It is denoted by a dotted arrow. There are two types ofdummies:

Identity Dummy. It helps to keep the designation of eachactivity unique or different from another.

Dependency Dummy. It helps to keep the logic correct.

Definitions

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Dr. CH. VENKATAIAH

Associate Professor310-Project Management

Activity arrows should be drawn from left to right

indicating progressive approach towards the

ultimate objective or the final event.

Crossing of activity arrows should be avoided.Arrows should be drawn as straight or bent

lines but not curved lines.

Avoid use of unnecessary dummies.

Activities are set in the order of their execution.

Events are set in the order of their occurrence.

Rules and Conventions

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Head event number should be greater than tail

event number. No event is numbered until the

tail event of each activity arrow ending into that

event has been numbered. There should be no danglers or loops. Danglers

are activities which lead no where. All activities

must be connected to events and the finishing

activities must be connected to the finish eventof the project.

Rules and Conventions

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Dr. CH. VENKATAIAH

Associate Professor310-Project Management 15

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 projectduration

Critical Activities

All of the activities that make up the critical path


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Dr. CH. VENKATAIAH


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

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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Dr. CH. VENKATAIAH


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 activitycan 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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Dr. CH. VENKATAIAH


It is used where activity duration is known withcertainty.

Activities are identified.

Dependency of activities is determinedNetwork is drawn

Earliest start times and latest finish times arecalculated

Critical path and critical activities are identified

Critical Path Method

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Dr. CH. VENKATAIAH


Rasoi Appliances wants to launch a newly

designed microwave oven.

Activities required for the launch have been

identified. Their relationship with each other

and the activity duration have also been

determined.

Example

19

Acti it Acti it Description Predecessor Time


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Dr. CH. VENKATAIAH


Activity

Symbol

Activity Description Predecessor Time

(days)

A Develop advertising plan - 6

B Develop promotion and training

materials plan

- 7

C Develop training plan - 8

D Schedule Radio,TV and print media

advertising

A 20

E Develop advertising copy A 18

F Prepare promotional material for in-store introduction

B 9

G Prepare material for training of

stores representatives

B 8

H Conduct pre-introduction advertising

campaign

D, E 7

I Select store representatives for

training

C 2

J Conduct training G, I 14

K Final in-store launch of product F, H and J 10


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Dr. CH. VENKATAIAH


8

C

A

B

6

7

Drawing a Network. We can start withactivities A, B and C as they have nopredecessors.

Consider the activities which can follow only A or B or C asthese have been completed. D and E follow A, F and Gfollow B and I follows C. Add these activities to the network.

Activity H is dependent on the completion of Activities Dand E. Activity J is dependent on completion of Activities Gand I. Add these activities to the network.

A dummy activity L has been drawn. This is an identitydummy. Add activity K which can start only when activitiesH, F and J are completed.

Start from the left and number the nodes as we move to theright of the network in the order of their appearance. If two ormore nodes are on the same line, number from top to bottom.

If the dummy L had not been put, then node 5 would havebeen eliminated and activity E also would have ended atnode 7. In that case, a reference to activity between nodes2-7 would refer to both D and E causing problems of

unique reference. D

E

F

G

I

20

18

9

8

2

L

J

H

7

14

K

101

2

3

4

5

6

7

8 9


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Dr. CH. VENKATAIAH


The earliest that the project can start is attime zero.

The earliest finish time for an activity is the

earliest start time + activity duration.The earliest start time of an activity which is

dependent on two or more activities is thetime at which all the preceding activities are

completed.

Calculating Earliest Start Time (EST)

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Dr. CH. VENKATAIAH


C

A

B

6

7

8

D

E

F

G

I

20

18

9

8

2

L

J

H

7

14

K

10

0

6

7

8

26

24

15

33 43

1

2

3

4

5

6

7

8 9

At Node 2, EST is = EST at Node 1 + Activity Duration of A

= 0 + 6 = 6

At Node 3, EST is = EST at Node 1 + Activity Duration of B

= 0 + 7 = 7

At Node 4, EST is = EST at Node 1 + Activity Duration of B

= 0 + 8 = 8

Node 7 is the starting event for activity J. Activity J can start only when

activities I and G are completed. Activity I can be completed earliest by 8 + 2

= 10, while G can end earliest on 7 + 8 = 15. Hence the earliest that J can

start is the end of 15th day.

At Node 6, EST is = EST at Node 2 + Activity Duration of D =

6 + 20 = 26, and (from Node 5 to Node 7) 24 + 0 = 24. Earliest H can start

is 26.

At Node 5, EST is = EST at Node 2 + Activity Duration of E

= 6 + 18 = 24

At Node 8, we get

From 7 to 8, 26 + 7 = 33. From 3 to 8, 7 + 9 = 16

From 6 to 8, 15 + 14 = 29. Earliest K can start is 33.

At Node 9, EST = EST at Node 8 + duration of activity K

= 33 + 10 = 43


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Dr. CH. VENKATAIAH


The project will take 43 days.

Start form Node 9 as 43 days and work

backward to find out the latest time when

the starting event of an activity must occur,

or the latest time by which all preceding

activities must finish so that the project is

not delayed

Latest Finish Time

24


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Dr. CH. VENKATAIAH


C

A

B

6

7

8

D

E

F

G

I

20

18

9

8

2

L

J

H

7

14

K

10

0

6

7

8

26

24

15

33 43

4333

26

19

26

17

0

11

6

At Node 8, LFT is = LFT at Node 9Activity Duration of K

= 4310 = 33

At Node 6, LFT is = LFT at Node 8Activity Duration of H

= 337 = 26At Node 7, LFT is = LFT at Node 8Activity Duration of J

= 3314 = 19

At Node 5, LFT is = LFT at Node 7Activity Duration of L

= 260 = 26

At Node 3, LFT is = LFT at Node 6Activity Duration of G or

LFT at Node 8Activity Duration of F

= 198 =11 or 339 = 24

If event 3 occurs at 24 then the project will get delayed. LFT is = 11

At Node 4, LFT is = LFT at Node 6Activity Duration of I

= 192 = 17At Node 2, LFT at Node 5Activity Duration of E or

LFT at Node 7Activity Duration of D.

Take the smallest value. At Node 2, LFT is = 6

At Node 1, LST = 0

1

2

3

4

5

6

7

8 9


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Dr. CH. VENKATAIAH


Spare time in an activity is called float. It isused to economise on resources withoutaffecting the overall duration of the project.

Types of floatsTotal float

Free float

Interference float

Independent float

Floats

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Total Float. It is the spare time available on any given

activity if the tail event occurred at its earliest time

and the head event at its latest time.Total Float = Time Latest at HeadTime Earliest at

TailActivity Duration.

= 3043 = 23

27

4EST 26EFT

30LST8LFT

G

3

Total Float. = 3043 = 23

Free Float. The spare time available on an activity if both the tail and thehead events occur at their earliest time. If this spare time is used up

during the execution of this activity, it will have no effect on subsequent

activities.

Free Float = Time Earliest HeadTime Earliest Tail

Activity Duration

= 2643 = 19


Free Float. = 2643 = 19

Interference Float.It is equal to total float less free float. If this float is used

up in an activity, it will interfere with the availability of floats available for

subsequent activities.

Interference Float = Total FloatFree Float

= 2319 = 4


Free Float. = 2643 = 19

Interference Float.= 2319 = 4Independent Float.The spare time available in an activity which is

neither affected by the use of float by preceding activities nor

does it affect the float available in subsequent activities.

Independent Float = Time Earliest HeadTime

Latest TailDuration.

= 2683 = 15


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Dr. CH. VENKATAIAH


PERTProgramme Evaluation andReview Techniqueis used inprobabilistic situations when the durationof activities is not known with certainty.

Three time estimates are used for activitydurationpessimistic time, optimistic timeand most likely time.

Mean time for each activity is calculated.

Network is drawn as for CPM with meantimes as activity durations

PERT Network

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Dr. CH. VENKATAIAH


Critical activities are identified.

Standard deviation on the critical path iscalculated.

Using the standard deviation and the meanand assuming normal distribution, projectduration with different levels of confidence orvice versa can be computed.

PERT Network

31


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Dr. CH. VENKATAIAH


Standard deviation cannot be added. Variance can be

added. Standard deviation on the critical path is

PERT - Network

32

4Mean Time

6

o m pt t t

Standard Deviation6

p ot t

2 2 ...A BSD SD


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Dr. CH. VENKATAIAH


PERT - Example

33

Activity Predecessor Optimistic Time

(to)

Most likely

Time (tm)

Pessimistic

Time (tp)

A - 1 2 3

B - 1 2 3

C - 1 2 3

D A 1 2 9

E A 2 3 10

F B 3 6 15

G B 2 5 14

H D, E 1 4 7

J C 4 9 20

K J, G 1 2 9

L H, F, K,

Finish

4 4 4


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Dr. CH. VENKATAIAH


Solution

34

Activity OptimisticTime (to)Mostlikely

Time (tm)

PessimisticTime (tp)MeanTime StandardDeviation

A 1 2 3 2 0.33

B 1 2 3 2 0.33

C 1 2 3 2 0.33D 1 2 9 3 1.33

E 2 3 10 4 1.33

F 3 6 15 7 2.00

G 2 5 14 6 2.00

H 1 4 7 4 1.00

J 4 9 20 10 2.67

K 1 2 9 3 1.33

L 4 4 4 4 0


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Dr. CH. VENKATAIAH


Draw the network and find critical activities

35

51

1

1 98

7

6

5

4

3

2

B

HE

D

A

LF

C

G

J K

2

3

4 4

2

6

7

2 10 3

4

1915

122

6

0

2

2

1

91

5

1

2

2

0

1

1

7

6

C, J, K and L are critical activities. Critical path is 14789

Project will be completed in 19 days or less with 50% confidence.


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Dr. CH. VENKATAIAH


Activity Optimistic

Time (to)

Most

likely

Time (tm)

Pessimistic

Time (tp)

Mean

Time

Standard

Deviation

C 1 2 3 2 0.33

J 4 9 20 10 2.67

K 1 2 9 3 1.33

L 4 4 4 4 0

2 2 2 2

2 2 2 2

S. D.

0.33 2.67 1.33 0

3

C J K LSD SD SD SD


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Dr. CH. VENKATAIAH


With 84% level of confidence how much time would theproject take?

PERT assumes that the distribution of the total projectcompletion time is normal. 84% represents Mean + 1

standard deviation. We can say with 84% level ofconfidence that the project will finish in 22 weeks.

What are the chances that the project will finish in 20weeks?

20 19 0.33

3

x

z

19 20

0.33 SD

From normal distribution tables the probability when z =0.33 is 0.6290.

There is a 63% chance that the project will finish in 20 weeks.


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Dr. CH. VENKATAIAH


PERT is a probabilistic model and is based on three timeestimates. It is used mainly for projects where the activitydurations are uncertain, like research and developmentprojects. Levels of confidence and probabilities can be

associated with the completion date of a project. CPM is based on certainty of the activity durations. It is

used for projects where there is certainty about the timethat each activity would take. The project completionduration is not probabilistic but is certain.

DifferencesPERT and CPM

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Dr. CH. VENKATAIAH

Associate Professor

Any Queries???

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Documents

Unit II Project Planning Revised