edp final seminar report

8/3/2019 EDP Final Seminar Report

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Group members :-

Hafsa Thasneem [6]

Sunanda [16]

Nadira [26]

Reshma [36]

Sarika [46]

Shihas [56]


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Developed in 1950s

CPM by DuPont for chemical plants

PERT by U.S. Navy for Polaris missile

PERT was developed by the US Navy for the planning and control of

the Polaris missile program and the emphasis was on completing theprogram in the shortest possible time. In addition PERT had theability to cope with uncertain activity completion times (e.g. for a

particular activity the most likely completion time is 4 weeks but it

could be anywhere between 3 weeks and 8 weeks).

CPM was developed by Du Pont and the emphasis was on thetrade-off between the cost of the project and its overall

completion time (e.g. for certain activities it may be possible

to decrease their completion times by spending more money -how does this affect the overall completion time of the

project?)


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CPM - Critical Path Method

In CPM activities are shown as a network of precedence relationships

using activity-on-node network construction

Single estimate of activity time

Deterministic activity times

USED IN : Production management - for the jobs ofrepetitive in

nature where the activity time estimates can be predicted with

considerable certainty due to the existence of past experience.


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PERT -

Project Evaluation & Review Techniques

In PERT activities are shown as a network of precedence relationships

using activity-on-arrow network construction

Multiple time estimates

Probabilistic activity times

USED IN : Project management - for non-repetitive jobs (research and

development work), where the time and cost estimates tend to be

quite uncertain. This technique uses probabilistic time estimates.


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A project is composed of a number of jobs,

activities, or tasks that are related one to the other

and all of these should be completed in order to

complete the project. An activity of a project can

start only at the completion of many other

activities. A network is a combination of activities

and events of a project.

NETWORK ANALYSIS


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Events represent instants in time when certain activities have

been started or completed.

Tail event: a tail event is the one which marks the beginning

of an activity. Head event : all the activities have an ending, marked by

an event, such an event is known as head event.

Successor events: The events that follow an event are

called successor events

Predecessor events: The events that occur before an event

are called predecessor events

EVENT


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Earliest event time (TE): The earliest occurrence time or

earliest time (TE) is the earliest at which an event can occur.

Earliest occurrence of an event say 2 is denoted by E2

Latest event time (TL): The latest allowable occurrence

time or the latest event time (TL) is a latest time by which an

event must occur to keep the project on schedule. Latest

occurrence by an event say 2 is denoted by L2

EARLIEST AND LATEST EVENT

TIMES


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Earliest start time(EST)

EST of an activity is the earliest time by which it cancommence.This is naturally equal to the earliest event timeassociated with the tail event of the activity.

The EST of an activity=earliest occurrence of the tail eventof the activity.So for the activity 2-3,EST is E2

Earliest finish time(EFT)

EFT for an activity is defined as the earliest time, by which itcan be finished. This is evidently equal to the earliest starttime plus estimated duration of the activity.

i.e EFT = E S T+ Activity duration

START AND FINISH TIMES OF AN

ACTIVITY


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Latest finish time (LFT)

The latest finish time for an activity is the latest time by

which an activity can be finished without delaying the

completion of the project.

Therefore for an activity 2-3, LFT =L3

Latest start time(LST)

LST of an activity is the latest time by which an activity can be

started without delaying the completion of the project. It should be normally equal to the latest finish time minus the

activity duration.

LST= LFT-Activity duration.

Cont..


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Critical Path Method (CPM )

CPM is a network technique which consist of

planning the sequence of activities to be performed in a

network

scheduling the time and resources to various operations

controlling theperformances so that they are not

deviating from the plan.

CPM is generally used for thoseprojects or for those projects

for which fairly accurate estimate of time for completion of activity

can be made and for which cost estimation can be made with fair

degree of accuracy.

CPM can be used effectively in productionplanning , road

system an traffic schedules, communication network etc..


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Steps in CPM

1. List allthe activities and draw a network

diagram

2. Find the Earliest event time and Latest event

time of each event and show in the networkdiagram.

3. Calculate Earliest start time, Earliest finish

time, Latest start time and Latest finish timefor each activity.

4. Determine float for each activity.

5. Identify the criticalactivities.


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Phases of Application ofCPM

technique

Planning

Scheduling

Resource allocation

Controlling


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Advantages and Disadvantages ofCPM

Advantages:

It makes better detailedplanningpossible.

Helps in ascertaining the time schedule.

Controlby management becomes easy.

Identifies most criticalelements & thus more

attention can be paid on these activities.Facilitates optimum utilization of resources


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Disadvantages:

Ignores statisticalanalysis in determining the time

estimate.

Difficult to use CPM when changes are introduced

into network.

It cannot itself solveproblem. It facilitate solution

for aproblem.


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example

Illustration of network analysis of a minor redesign of a product andits associated packaging.

The key question is: How long will it take to complete this project ?


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For clarity, this list is kept to a minimum by specifying only

immediate relationships, that is relationships involving activities

that "occur near to each other in time".


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"What activities must be finished before this activity can start"

could we complete this project in 30 weeks?

could we complete this project in 2 weeks?

One answer could be, if we first do activity 1, then activity 2, then activity 3,

...., then activity 10, then activity 11 and the project would then take the sumof the activity completion times, 30 weeks.

What is the minimum possible time in which we can complete this project ?

Before starting any of the above activity, the questions

asked would be


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We shall see below how the network analysis diagram/picture we construct

helps us to answer this question.


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CRITICAL PATH TAKES 24 WEEKS FOR THE COMPLETION OF THE PROJECT


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Packages are available to determine the shortest path and

other relevant information.

AdeptTrackeris a powerful Critical Path Analysis Software for you to analyze, schedule, andmanage projects. As a

low-price project management software product, AdepTracker 's Critical Path Analysis features enable you to trackproject, schedule project and manage project in a very convenient and effective way.


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Data entry window


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Output of the package


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PERT

Programme Evaluation ReviewTechnique


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PERT

PERT is a network technique of scheduling and

controlling the project where activity times

cannot be precisely estimated. It is a

probilistic model with a degree of uncertainity

in activity duration.


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PERT deals with the problem of

uncertain activity times

1. Optimistic time (to)

2. Pessimistic time (tp)

3. Most likely time (tm)

Expected time (te) = to+4tm+tp

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Steps in PERT

1. Activities are arranged in a logical sequence

2. Network diagram is drawn and events are

numbered

3. The expected time for each activity is calculated

4. Marked the diagram

5. SD and varience for each activity are found

6. Slack is calculated and critical path is identified

7. The total project duration is worked out


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Application ofPERT

Defence projects

Research and development projects

In construction projects In installing machinary

In maintaince ships, rockets, steel etc

In administration of the organisation In budgeting of the organisation


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Resource Leveling

Resource leveling is the project management

function of resolving project resource over-

allocation. By definition over-allocation means

that a resource has been assigned more work

than can be accomplished in the available

time as dictated by the resource's calendar

definition.


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Over-allocation

Over-allocation can occur as the result ofvarious events:

Increased work on a task that causes the finish

date to overlap with another already assignedtask.

A forecasted finish that causes a task to slip or

delaying . Full time assignments to tasks that start and

end at the same time or overlap.


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Cont

Resource leveling is the process that ensures

resource demand does not exceed resource

availability.


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Example:

if a resource (human) is assigned to work 8

hours on a project on Monday and then is

scheduled to work full time on four tasks on

Monday, the resource would need to put in

thirty-two hours of work in order to stay on

plan. Obviously it is impossible to work 32 hours

in one day so the resource is over allocated.


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ways to level resources

Delay tasks:

The delay of tasks can be assignment

delay or leveling delay.Splitting a task:

It is the process of interrupting the task

schedule. In this way, part of the task is done

when planned and the rest of it is done later

when the assigned resource has time.


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If networks are used as the primary planning method there are two

approaches

Time-limited resource considerations

emphasis is placed on completing theproject within a

specified time, which is typically determined by network analysis.Adjustments in the timing of an activity and the resources

allocated at a given time are made within the available float.

Activities on the criticalpath are not adjusted


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Resource-limited considerations

projects must be completed with the available

resources, even if that means extending the

duration of the project. If the totalresource

demand exceeds the resource availability, at

any time, then some of the activities must be

delayed untilthere is sufficient resource

availability


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edp final seminar report

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