System Development Project“A project is a series of activities directed towards

accomplishment of a desired objective.”

“A project is a temporary endeavour undertaken to create a "unique product or service”

Network analysis

Network analysis is the general name given to certain specific techniques, which can be used for the planning, management and control of projects.

CPM, PERT are the two most used techniques.

Plan your work first…..then work your plan

History

PERT was developed by the US Navy for the planning and control of the Polaris missile program and the emphasis was on completing the program in the shortest possible time. In addition PERT had the ability 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 the trade-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?)

CPM - Critical Path Method Uses Deterministic activity times

used in: Production management - for the jobs that are of repetitive nature , where the activity time estimates can be predicted with considerable certainty due to the existence of past experience.

PERT - Project Evaluation & Review TechniquesUses Probabilistic activity times

used in : Project management - for non-repetitive jobs (information system development work), where the time and cost estimates tend to be quite uncertain. This technique uses probabilistic time estimates.

CPM/PERT

o Use networks, that contain nodes and activities

o Over time CPM and PERT became one technique

o Networks indicate precedence relationships

o Can be used effectively in case of large projects

The Project Network

Use of nodes and arrows

Arrows Indicate ACTIVITY, a time consuming effort that is required to

perform a part of the work. An arrow leads from tail to head directionally

Nodes A node is represented by a circle

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

PERT/ CPMActivityTime(week) activity time1-2 4 5-6 41- 3 1 5 -7 82- 4 1 6- 8 13- 4 1 7- 8 23- 5 6 8- 9 14 -9 5 8- 10 8

9- 10 7

PERT/ CPMPERT network

1

2

3

4

1

4

5

6 8

7

9

10

1

111

11

11

61

4

1111

21

81

81

71

E1=0

E2=4

E3=1

E4=5

E5=7

E6=11

E7=15

E8=17

E9=18

E10=25

L10LL10 =25

L9 =18

L8=17

L7 =15

L6=16

L5= 7

L4 = 13

L3=1

L2 =12

L1 =0

PERT /CPMActivitytime (week) activity time1-2 2 4- 7 41- 3 2 5- 8 21- 4 2 6- 8 42- 5 4 7- 9 53- 6 5 8- 9 33- 7 8 9 -10 4

Network

1

2

3

5

6

4

8

7

9 10

2

5

42 34

8

5

2

2

4

4

PERT/ CPMActv 1-2 1-3 1-4 2-5 2-6 3-6 4-7 5-7 6-7

T(o) 5 18 26 16 15 6 7 7 3T(p) 10 22 40 20 25 12 12 9 5T(m) 8 20 33 18 20 9 10 8 4

Times are in days T(o)= Optimistic timeT(p)= pessimistic timeT(m) = most likely time

Expected time T(e)={T(o)+4T(m)+T(p)}/ 6

T(e)= 7.8 20 33 18 20 9 9.8 8 4