1. Lecture 4: Software Process Management Dr Valentina Plekhanova University of Sunderland, UK http://www.cet.sunderland.ac.uk/~cs0vpl/SE-Com185.htm

2. Lecture 4Valentina Plekhanova 2 Process Models … process models Existing process models represent various projects goal(s) and this defines an ordering of project (tasks) activities.

3. Lecture 4Valentina Plekhanova 3 Project Management project management In contrast with software process models, project management deals with resources. Moreover, it is used as a means to provide planning, organisation, direction and control of resources in order to meet an organisation’s objectives by a specific date and within a well- defined budget. Project management involves the application of limited resources to the completion of tasks in the most effective and efficient manner.

4. Lecture 4Valentina Plekhanova 4 Project Scheduling A pivotal problem of project management is to find the best trade-offs among resources. project management scheduling Support for the co-ordination of people, tasks, equipment, products, time and money is provided by project management scheduling.

5. Lecture 4Valentina Plekhanova 5 Planning Phase: Estimating Duration & Cost … ??? Duration Duration … the duration of the project  Another important part is estimating the duration of the project.  However, in estimating these issues a large number of variables are involved, principally the human factor.

6. Lecture 4Valentina Plekhanova 6 Cost Estimation An accurate cost estimation is an integral part of any software project management plan. A number of approaches can be used for cost estimation. These include: Expert judgement by analogy: consultation between a number of experts to devise a cost structure based on previous similar projects he/she has worked on Bottom-up approach: breaking the target product into smaller units.

7. Lecture 4Valentina Plekhanova 7 COCOMO A number of algorithmic models have been devised. Constructive Cost Model The major one is Boehm’s Constructive Cost Model (COCOMO).

8. Lecture 4Valentina Plekhanova 8 Training Requirements Staff must be trained in new software development methods; operating systems, documentation preparation and hardware. A training plan must then be incorporated into the SPMP.

9. Lecture 4Valentina Plekhanova 9 Project Management:Metrics Project Management: Metrics Metrics can be used to measure the size of a product. These include:  Lines of code (?!)  Thousand delivered source instructions (?!)  …?

10. Lecture 4Valentina Plekhanova 10 Project Management:Metrics Project Management: Metrics However, the above metrics are dependent on the language used, whether executable or comments should be counted and not all source code is delivered to the client.

11. Lecture 4Valentina Plekhanova 11 Project Management Tools Critical Path MethodProgram Evaluation Report technique Well-known management tools are Critical Path Method (CPM) and Program Evaluation Report technique (PERT). These tools are used to assist in the planning phase. This can determine which activities are critical and may delay the project if not completed on time.

12. Lecture 4Valentina Plekhanova 12 Basic Project Management Scheduling Techniques There are different types of schedules. Gantt charts CPMPERT Some of the basic ones are Gantt charts, CPM and PERT types.

13. Lecture 4Valentina Plekhanova 13 Gantt Charts Gantt charts Gantt charts is the typical method of scheduling construction projects. The primary limitation of this technique, as is outlined in literature is its inability to direct attention to the interrelationships and interdependencies among the activities.

14. Lecture 4Valentina Plekhanova 14 Gantt Charts

15. Lecture 4Valentina Plekhanova 15 Critical Path Method CPM type CPM type is based on the Critical Path Method. This type looks for the schedule with minimum cost in a definite period of time in the case where the cost is associated with each activity. Time is a resource. The resource allocation problem is to allocate time among project tasks.

16. Lecture 4Valentina Plekhanova 16 Critical Path Method …& SE..??! A B C D E F V 10 15 20 10 10 10 5 5 15 ACDFV50 ABEV 30 ACDFV 50 ACDV 30 ADFV 45 ADEV 35

17. Lecture 4Valentina Plekhanova 17 Program Evaluation Review Techniques PERT type PERT type, which is based on the Program Evaluation Review Techniques, looks for the schedule, which minimises the objective function such as project time (total elapsed time). That is, it determines the start and completion times of each activity.

18. Lecture 4Valentina Plekhanova 18 CPM & PERT CPMPERT Both techniques CPM and PERT use network methods to assist in project management and to overcome the interrelationship limitation in Gantt charts. CPM & PERT Both these techniques CPM & PERT identify a project critical path whose activities could not be delayed, and also indicate slack activities that could be somewhat delayed without lengthening the project completion time.

19. Lecture 4Valentina Plekhanova 19 CPM & PERT: Difference CPM construction PERT research and development CPM and PERT have the underlying difference. From its origin viewpoint, the CPM technique was developed for construction projects, while PERT was elaborated for research and development projects.

20. Lecture 4Valentina Plekhanova 20 CPM construction industry In the construction industry, prior experience with similar projects can be used to predict time estimates for projects within a relatively tight range. single point estimate predictable or deterministic In the CPM method the expected activity time is a single point estimate that assumes certainty: each activity is considered of exact fixed length. That is, CPM assumes that time is predictable or deterministic.

21. Lecture 4Valentina Plekhanova 21 PERT researchdevelopment projects However, with research and development projects, a great deal of uncertainty is associated with time estimates because no previous similar experience exists and precise time estimates are not available. PERT assumes the time estimate for an activity lies within the range of earliest time and latest time.

22. Lecture 4Valentina Plekhanova 22 PERT PERT [Gray, 1981] three time estimates PERT uses three time estimates (optimistic, most likely, and pessimistic) to compute the average or expected time. random variation stochastic PERT offers a way of dealing with random variation and considers each activity stochastic in that variability is allowed in each activity.

23. Lecture 4Valentina Plekhanova 23 PERT PERT [Plekhanova, 1998; Plekhanova 2000] research development projectscognitive tasks It should be pointed out, that PERT was developed for research and development projects, which consist of cognitive tasks. However, PERT is not concerned with the specific character of cognitive tasks.

24. Lecture 4Valentina Plekhanova 24 CPM & PERT PERT&CPM have been found to be useful in project management to provide efficient resource scheduling. In particular, PERT&CPM identify the critical jobs, which control the project completion date. Moreover, the application of these tools reduces the degree of scheduling errors and, hence, increases the cost savings.

25. Lecture 4Valentina Plekhanova 25 CPM & PERT However, as mentioned in project management literature, the actual savings derived from using PERT&CPM methods are difficult to identify and measure precisely.

26. Lecture 4Valentina Plekhanova 26 Note that [Plekhanova 2000]… resource availability and utilisation existing project management scheduling tools are concerned with a problem of resource availability and utilisation, not with capability and compatibility of project resources. There is, therefore, an assumption that the quality of project resources does not have an impact on project scheduling and task performance.

27. Lecture 4Valentina Plekhanova 27 Paradox !!!! [ Paradox !!!! [Plekhanova 2000] We have a paradoxical situation, in that contemporary project management approaches (both mathematical and heuristic based) cannot be sufficiently employed in complex situations [Gray, 1981] and, yet, they are used for complex situations in practice.

28. Lecture 4Valentina Plekhanova 28 Management is a human activity ! It is important to notice that although there are many project management (scheduling) tools, use of them does not guarantee success. Management is a human activity and project success depends on the competence of management. Management is a human activity and project success depends on the competence of management.