1. 1 Project Management Software Engineering 2004-2005

2. 2 What is a project? A piece of work that is undertaken Usually has a recognised beginning and end Usually has identifiable stages

3. 3 Software Project Traditional software development approach Definite stages Definite end point Similar to creating a building

4. 4 Open ended Software Project When does maintenance end?

5. 5 Implementation Program / module development –Each individual module developed and tested as a discrete unit Systems testing –Programs/modules combined and tested as sub-systems Conversion –Existing system converted to enable new system to operate on “live” data

6. 6 Planning is essential fo success Consists of –Estimating effort –Scheduling tasks –Monitoring their progress

7. 7 Estimating Steps –Identify the tasks –Estimate the effort required for each task –Identify total resources required –Identify minimum elapsed time for tasks

8. 8 Estimating – identifying tasks Can be like top-down design –How to get to the top of Mt Everest from Liverpool? –Break it down into steps

9. 9 Estimating – identifying tasks in a software project

10. 10 Estimating – identifying tasks in your individual project Your individual project plan will only be concerned with implementation Can you identify tasks in implementing your individual project? Clues: –Use case diagram –Class diagram Need to complete these before you can plan your project

11. 11 Estimating – effort required for each task Measured in person-days

12. 12 Factors affecting estimating effort the complexity of the processing required the number of input and output types (files, screen interaction, etc.) the number of data structures involved the programming language to be used the machine time available for development the experience of the staff involved

13. 13 Factors affecting estimating effort the development support facilities the novelty of the application the type of application ('real time' applications are notoriously more demanding than 'batch' applications) the novelty of the computer equipment and support environment the development methodology employed

14. 14 Estimating – total resources required Computer equipment System software licences– compilers etc Accommodation Secretarial support User support –Liaison –Answering technical queries

15. 15 Estimating – minimum elapsed time Writing a class may take 4 person days So 4 people could do it in 1 day? Or 40 people could finish it in 50 minutes?

16. 16 Scheduling Allocating tasks to individuals Determining appropriate start times and end times for each task

17. 17 Scheduling example

18. 18 Scheduling example Estimates

19. 19 Scheduling example

20. 20 Exercise 2 Suppose that for the development of this module, only one hour of access to the computer equipment each day is available. What effect will this have on each stage of development?

21. 21 Exercise 2 Suppose that for the development of this module, only one hour of access to the computer equipment each day is available. What effect will this have on each stage of development? 3 x 1 hour per day computer time needed 18 x 1 hour per day computer time needed

22. 22 Sitting around doing nothing time Total elapsed time is 29 days Effort required is 20.5 days Thus programmer sitting around doing nothing for 8.5 days.

23. 23 Trying to solve this problem Waste of valuable resources The notes show the complexity and pitfalls of trying to solve the problem by assigning him/her to other tasks while waiting Need to take into account the overhead required to switch intellectual tasks and the problems this can cause

24. 24 Aim of scheduling Identify when tasks can begin and when they are expected to end Can be shown in a Gantt chart

25. 25 How to make a Gantt chart Identify the estimated elapsed time for each activity Identify the dependencies –What other tasks must be completed before each task can start Derive a network diagram Use it to draw the Gantt chart

26. 26 Elapsed time and dependencies

27. 27 Network diagrams Activities represented by lines Start and end points of activities are called events – represented by circles

28. 28 Events

29. 29 Drawing a network diagram

30. 30 Entering the earliest expected times (EAT) 40 50 Two earliest times Always use the latest

31. 31 Try this

32. 32 Latest of the three is 48 so it goes into the event

33. 33

34. 34 Entering the latest allowable times (LAT) 30 20 Two latest times Always use the earliest

35. 35 Analysing the network Find maximum span for each activity Max span = LAT end – EAT start Max span = 38 - 20 = 18

36. 36 Spans and floats Total float = Maximum span – estimation duration Results in the above

37. 37 Complete the table

38. 38 Completed table

39. 39 Meaning of total float zero Any delay in a zero float activity delays the whole project Delay of 5 days in T.Util delays whole project by 5 days Delay of 5 days in Sc.E does not delay the project at all since this delay is within the available float for Sc.E

40. 40 Identifying the critical path Critical path is the list of activities with total float zero Any delay in any activities on the critical path delays the whole project

41. 41 Adding activities to the project

42. 42 A first attempt Implies Sc.E (screen entry) also depends on acquiring special stationary – not true

43. 43 Better Rep depends on Ospec and T.Util completing Sc.E only depends on T.Util completing Dotted line is a dummy activity (0 length)

44. 44 Modified max spans Critical path: Req.A, De, T.Util, Sc.E, Val, Sys.T

45. 45 Gantt Chart for last exercise For each rectangle: –Left hand edge is at earliest estimated time –Length of rectangle = estimated duration