Project Management

Project is defined as a huge (mammoth) task which for convenience of management is broken down into smaller elements such that, for each of the smaller elements, one can identify the finite requirements of resources and finite requirements of time. These smaller elements are referred as activities of the project i.e. project essentially comprises of a number of activities e.g. construction of building is a project and electrical work is one of the activities of the project.

Contd…

Slide 1

Project Management

Like the electrical activity, a project will have a number of activities. The first task of the project manager is to define all the activities of the project in terms of time and other dimensions like cost etc. The second task is to establish the inter relation & interdependence of the defined activities. The following are some examples to explain small projects.

Slide 2

Example 1

Activity DescriptionImmediate

predecessorsDuration (weeks)

A Select location - 2

B Obtain speakers - 3

C Make speaker travel plans A, B 2

D Prepare and mail brochure A, B 2

E Take reservations D 3

Christine Philips is in charge of planning and coordinating next spring’s sales management training program for her company. Christine has listed following activities information for this project.

Draw the network diagram; find the critical path and the duration along the critical path.

Slide 3

Activity Description Immediate predecessors

Duration (days)

A Determine output voltages - 5

BDetermine whether to use solid state rectifiers A 7

C Choose rectifiers B 2

D Choose filter B 3

E Choose transformer C 1

F Choose chassis D 2

G Choose rectifiers mounting C 1

H Layout chassis E, F 3

I Build and test G, H 10

A research and development department is developing a new power supply for a console television set. It has broken down the job into the following form:

Draw the critical path schedule, indicate the critical path. What is the time required for completion for the project?

Example 2Slide 4

Categories of Project

The following is an illustrative list of categories of project:i. Complex projects with unknown elements for e.g.

Construction of nuclear power plants ii. Large projects with standard elements for e.g. Construction of

an automobile factory iii. Intermediate project for e.g. layout of machine, implementing

TQM programme, developing new markets etc.iv. Small projects for e.g. installing a new machine, conducting a

market survey etc.v. Turnkey project is one which starts from zero to proceed to a

finished ‘product’. Concept of turnkey is that when the project is finished one turns a key to set the facility in operation, for e.g. Reliance refinery project at Jamnagar is a turnkey project.

Slide 5

Session Objective

Given the activities, their duration and their inter relation,

our objective in this session is:

i. to represent these relation of activities in the form

of a network diagram

ii. to analyze the network diagram using CPM (Critical

Path Method)

Slide 6

Network Diagram

Network diagram is a graphical / pictorial

representation of a series or a sequence of activities in

the logical order of their performance, such that we

establish the inter relation and interdependence of one

activity on all other activities of the project.

Network Diagram comprises of two basic elements:

(i) Activity

(ii) Event (Node)

Slide 7

Elements of Network Diagram

i. Activity: An activity is denoted by an arrow

It signifies the deployment of finite resources over a finite period of time. The tail of the arrow signifies the commencement of the activity and the head signifies the completion of the activity.

ii. Events or Nodes: An event is denoted by a circle

It signifies the status of the project at a point of time. It indicates the start & completion of an activity.

i

Tail Head

where, i={1,2,3,4…. and so on}

Slide 8

A-O-A Convention (i-j convention)

i jA

tij

i < j

Activity A or Activity i-j

Tail event signifies commencement status of the activity.

Head Event signifies completion status of the activity

Arrow signifies deployment of finite resources over a finite period of time.

tij is the duration of the activity

Tail Event Head Event

Slide 9

Good practices of drawing a Network Diagrami. Drawing a network diagram is a trial and error procedureii. The starting event is always one event, irrespective of the number

of starting activities. This event signifies the commencement status of the project

iii. The completion event is always one event, irrespective of the number of final activities. This event signifies the completion status of the project.

iv. The length of the arrow is the convenience of drawing the network diagram. It is no indication of the duration of activity.

v. The arrows must be drawn in the forward direction. Avoid crossing of arrows.

vi. The numbering of events starts with the first event and progressively moves from the left to the right of the network diagram

vii. There is no uniqueness in the final picture of the network diagram.

Slide 10

Good practices of drawing a Network Diagram

These Guidelines are explained with the

following five illustrations of network

diagram:

Slide 11

Analysis of Network Diagram

There are two popular tools used for analysis of Network

Diagram

CPM (Critical Path Method)

PERT (Program Evaluation & Review Technique)

In the following slides, CPM is explained with examples.

Slide 12

Manager’s View of Critical Path Method

Inputs(What information must

be supplied to CPM)

CPM

Outputs(What information results

from CPM that provides for better project management)

1. a complete list of project activities

2. Precedence relationship among activities

3. Estimate of each activities duration

1. Estimated duration of project

2. Identification of critical activities

3. Amount of Float for each activity

Slide 13

Critical Path Method It was developed in 1956 / 1957 by Remington Rand and Du-

pont to help schedule maintenance projects in chemical plants and construction projects.

Critical Path Method is a systematic scientific method based on principle of time estimates to perform a detailed analysis of Network in an application of Project Management

Time estimates in CPM relate to estimating the time for the events of the network diagram. Since the event signifies the status of the project at a point of time, the time estimates in turn signify the status of the project at different points of time. There are two important time estimates; (i) Earliest starting time & (ii) Latest finishing time.

Slide 14

Guidelines for Earliest Start Time (EST)

Earliest Start Time (EST): It signifies the earliest that an activity can start with reference to the commencement status of the project. The following are the guidelines to obtain EST.

i. Earliest starting time for event 1 is taken as zero because event 1 signifies the commencement status of the project i.e. status of the project corresponding to time ‘t = 0’.

ii. For the calculation of EST we start from event 1 and progressively move from left to right in the network diagram (referred as forward pass)

Slide 15

i jtij

Tail Event Head Event

Ei Ej

Ej = Ei + tij

EST of the head event EST of the tail event the duration of the activity= +

iii.Consider two adjacent events

Guidelines for Earliest Start Time (EST)

Slide 16

iv. Consider a merging event (in case more than one activity is merging towards an event).

b d

c

a

Ea

Eb

Ec

Ed

tad

tbd

tcd

Ed = Ea + tad

Ed = Eb + tbd

Ed = Ec + tcd

Take the maximum value

Guidelines for Earliest Start Time (EST)

Slide 17

Latest Finish Time (LFT): It is the latest time by which an activity should finish, otherwise the project completion time will be delayed. The following are the guidelines to obtain LFT.

i. For the last event of the network diagram, LFT = EST (because the last event signifies the project completion status and both EST / LFT signify the project completion time)

ii. For the calculation of LFT, we start with the last event of the network diagram & we proceed progressively from the right to the left of the network diagram (referred as backward pass).

Guidelines for Latest Finish Time (LFT)

Slide 18

iii. For two adjacent events

i jtij

Tail Event Head Event

LiLj

Li = Lj – tij

LFT of the tail event LFT of the head event the duration of that activity= –

Guidelines for Latest Finish Time (LFT)

Slide 19

31

4

2

L2

L1

t12

t13

t14 L3

L4

L1 = L2 – t12

L1 = L3 – t13

L1 = L4 – t14

Take the minimum value

For a bursting event (If there are more than one subsequent activities busting from an event), calculate LFT for each of the head events and take the minimum value

Guidelines for Latest Finish Time (LFT)

Slide 20

Note:

Both EST and LFT for starting event (event 1 of the network diagram) are always zero

Slide 21

Total Float of an Activity

Total Float signifies the maximum permissible delay in performing the activity without delaying the project completion time. The following is the mathematical relation for Total Float

Total Float of Activity LFT (Head Event)

EST (Tail Event)

Duration of Activity= – –

i jtij

Tail Event

Head EventEi

Lj

Total Float of Activityi-j = Lj – Ei – tij

Slide 22

Free Float of an Activity

i jtij

Tail Event Head Event

Ei

Lj

Ej

Li

Free float signifies the maximum permissible delay in commencement of an activity without affecting the commencement of the succeeding activity

Head Event Float = Lj – Ej

Free Float = Total Float – Head Event Float

Slide 23

Definition of Critical Path

If total float of an activity is zero, it means there is no permissible delay in performing the activity i.e. any delay in performing the activity will result in a corresponding delay in the project completion time. Such activities are referred as critical activities.

Path of network is a continuous series or sequence of activities that joins the first event with the last event of the network diagram.

In a network one can enumerate many sequences of activities from starting event to end event. Each sequence will contain different combination of activities with different duration.

Slide 24

Definition of Critical Path

To know the possible time by which the project can be completed, we determine the critical path i.e. the sequence of activities with longest duration. It is known as critical path and any delay in activities lying on this path would cause a delay in the whole project.

Alternately, Critical Path is a continuous series or sequence of critical activities that joins the first event with the last event of the network diagram.

To quicken the process, the activities lying on the critical path should be taken first. The activity lying on non-critical path has some flexibility in their starting time and their delay in start is not likely to affect the final completion date. These are known as slack activities and should be given priority in order of their float value.

Slide 25