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S/W Project Management Software Project Planning (POMA) Task Analysis.

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Presentation on theme: "S/W Project Management Software Project Planning (POMA) Task Analysis."— Presentation transcript:

1 S/W Project Management Software Project Planning (POMA) Task Analysis

2 Agenda Software Project Planning (POMA)  Task Analysis  Work Breakdown Structure (WBS)  Task Scheduling Task Analysis & Scheduling 2

3 Work Breakdown Structure Is a depiction of the project (model) in terms of the discrete pieces of work needed to complete the project and the ordering of those pieces of work. Performed by software project team. Focuses on the tasks required to produce the artifacts that are to be delivered. Task Analysis & Scheduling 3

4 Work Breakdown Structure As the details of the software development and support process are realized subtasks are identified. There are a number of tools used to support the WBS activity:  Graphical – MS Visio, Smartdraw, ArgoUML.  Scheduling – MS Project, Primavera TeamPlay Task Analysis & Scheduling 4

5 Work Breakdown Structure Steps in the WBS: 1. Examine the set of required external deliverables. 2. Identify and list the steps and tasks needed to produce the required deliverables, including intermediate deliverables. 3. Sequence the identified tasks required to produce the deliverable. 4. Estimate the effort required to perform each task. 5. Estimate the productivity of the resources that will be applied to the tasks. Task Analysis & Scheduling 5

6 Work Breakdown Structure Steps in the WBS: 6. Compute the time needed for each task by dividing the task effort estimates by the resource productivity estimates. 7. Lay out the time needed for each task and “label” each task with its task name and the assigned resources; this layout forms the initial schedule Task Analysis & Scheduling 6

7 Identify and list all deliverables For each deliverable: Identify and list the necessary tasks for completing the deliverable For each task: Compute the timeline required by dividing effort by productivity For each task: Estimate the productivity of the assigned resources For each task: Estimate the effort needed Sequence the tasks Lay out the timeline for all the ordered tasks need for each deliverable Perform task After the timelines for all tasks for all deliverable are computed Flow of WBS to schedule Task Analysis & Scheduling 7

8 WBS - Example Deliverable 1: Executable code that is installable from a CD. Deliverable 2: Help text, usage, and reference information that is installable from CD. Deliverable 1 activities:  To develop code: requirements specification, and analysis (which are already completed), design, coding, and testing.  To make code installable: requirements specification (already completed), design, coding and testing Task Analysis & Scheduling 8

9 WBS - Example Deliverable 2 activities:  Creating help text: requirements specification and analysis (already completed), design, writing, and testing.  Developing usage and reference information: requirements specification and analysis (already completed), design, writing, and testing. Task Analysis & Scheduling 9

10 WBS - Example Choice of activities and sequence depends on: 1. The size and complexity of both the problem and the solution, 2. The process and methodology that the software organization has defined and trained its people to follow, and agreed with its client to use. Sequencing the activities needed for the development of the artifacts can be a large problem for new software organizations. Task Analysis & Scheduling 10

11 WBS Task Refinement List of activities for Deliverable 1:  Activity A: Designing and documenting the design using an agreed upon notation  Activity B: Coding (in language agreed upon)  Activity C: Defining test cases and generating test scripts  Activity D: Executing test scripts  Activity E: Correcting and fixing problems found during testing  Activity F: Collecting the tested executable modules and handing them to the packaging group Task Analysis & Scheduling 11

12 WBS Task Refinement TasksDescription Task A-1Overall application, user interface (UI), and message architecture Task A-2Database and relational tables design Task A-3Application function 1 design Task A-4Application function 2 design Task A-5Application function 3 design Refinement of activity A: Table 2.1. Subtasks within the Design activity Task Analysis & Scheduling 12

13 WBS - Task Sequencing After the tasks refinement then comes the sequencing of the tasks. There are usually dependencies between tasks i.e., Task A-1 needs to be completed before Tasks A-2, A-3, A-4 and A-5 commence. There may also be overlap between tasks, i.e., Task A-2 maybe or may not be started before Task A-1 is completed. Task Analysis & Scheduling 13

14 WBS - Task Sequencing Sequence diagrams depict the start-stop relationships among the various subtasks. Sequence diagram – shows all the tasks required to complete an activity and the order in which those tasks must be performed, including the depiction of the tasks that may be performed in parallel. Task Analysis & Scheduling 14

15 WBS - Task Sequencing Task A-1 Task A-2 Task A-3 Task A-4 Task A-5 Fig. 2.2 Sequence diagram Tasks A-3, A-4, and A-5 maybe performed in parallel. Note there is no indication how task may overlap. Task Analysis & Scheduling 15

16 WBS - Task Sequencing Steps for the construction of the software project: 1. List the deliverables. 2. For each deliverable, list the activities that are required. 3. For each activity, list the set of subtasks that are required. 4. Further refine any of the subtasks by creating the next level of subtasks, if necessary. 5. Construct the sequence relationship of the subtasks 6. Depict the sequence relationship with a sequence diagram Task Analysis & Scheduling 16

17 WBS – Time and Resource Assignments What is a “satisfactory” level of refinement? Guidelines:  Each task may be assigned to one person.  The estimate of the task cost, stated not in terms of money but rather in terms of time required to complete it, does not extend beyond more than two or three project status meeting. Ensuring single person accountability makes the management and tracking of the task much easier. Task Analysis & Scheduling 17

18 WBS – Time and Resource Assignments Assume that project management meetings are conducted very often, daily, for a small project (range of weeks) and weekly if the s/w project is large (range of months < 1 year). Units of tasks management: Project team must decide on a unit of measurement, usually range from 1 hour units to a several days (< week). It is important to state hours in a day and days in a week (5 or 7) Task Analysis & Scheduling 18

19 WBS - Time and Resource Assignments Units of tasks management: Time must be allocated for non-direct-task-related activities e.g., departmental meetings, telephone interruptions etc. How to estimate time required to complete a task.  Ask experienced s/w engineers (bottom-up estimating).  Assemble a team and ask them to estimate each task in terms of some common work volume unit e.g., lines of code (LOC) per hour per day Task Analysis & Scheduling 19

20 WBS - Time and Resource Assignments TasksPossible rates Requirements elicitation2 interviews/person-day Message design15 messages/person-day Code implementation2 functions points/person-day; 40 lines of Java/person-day Test generation5 test scenarios/person-day Units of tasks management: Example of Historical Information Task Analysis & Scheduling 20

21 WBS - Time and Resource Assignments Task A-1 Task A-2 Task A-3 Task A-4 Task A-5 End 5 days 3 days 7 days 5 days 2 days Fig2.3 Subtasks with estimated times. Longest path includes A-1, A-2, and A-3 (critical path) There is no slippage along the critical path. Task Analysis & Scheduling 21

22 WBS - Time and Resource Assignments Estimates and assignments: Need to assign people to tasks. 1. Spmr need to consider skills required to perform each task, then seek people capable of performing these tasks. 2. Must consider the availability of the identified skilled people. 3. Must consider the timing of and the requirement of the identified person for another aspect of the project or another project. The above must be made in conjunction with the schedule in the time-estimated WBS. Task Analysis & Scheduling 22

23 WBS - Time and Resource Assignments Estimates and assignments cont: The dependencies of the tasks in the WBS restrict assignment of resources, it also allows for the use of additional resources. The skill of the team members may also restrict assignment. Task Analysis & Scheduling 23

24 WBS - Time and Resource Assignments SubtaskPersonSequence time-estimate A-1P1 A-2P2 A-3P3 A-4P4 A-5P5 Estimates and assignments: Subtasks with time Estimates and People Assignments 5 days 3 days 7 days 2 days 5 days Task Analysis & Scheduling 24

25 WBS - Time and Resource Assignments SubtaskPersonSequence time-estimate A-1P1 A-2P2 A-3P3 A-4P4 A-5P5 Milestones 5 days 3 days 7 days 2 days 5 days Minor MilestoneMilestone Task Analysis & Scheduling 25

26 WBS - Time and Resource Assignments Milestones: End-point of a software process activity. A significant event in a project that occurs at a specific point in time. The labeling of a milestone gives a certain amount of priority and significance to the event. Spmr may use the term “milestone” to emphasize the particular activity, as well as for the purpose of recognizing the attainment of a significant task. Task Analysis & Scheduling 26

27 WBS - Time and Resource Assignments Milestones: Depending on the size of the project the schedule might only be depicted in terms of milestones. Such a schedule may be used by higher level management. It is important for the spmr to recognize the accomplishments of milestones and publicly recognize them. The spmr should also pay attention to missed milestones. Task Analysis & Scheduling 27

28 Task Sequence and Effort representation All tasks share at least two basic characteristics  Require effort in terms of person-days required to complete each task  A specified order for processing the task Task Analysis & Scheduling 28

29 Task sequence/effort table TaskImmediate prerequisite tasks Effort (person-days) ANone9 BA5 CA7 DB,C11 ED8 Total effort required: 40 person-days Task Analysis & Scheduling 29

30 Graphical representation of tasks from previous table Task A Task B Task C Task D Task E End Critical Task Non-critical Task Critical Path Non-critical Path 9 9 5 7 118 Total project time: 35 days Task Analysis & Scheduling 30

31 Critical versus Non-Critical Paths Critical path The path that takes the most time to complete. Critical task (critical activity) A task that resides on the critical path. Non-critical path Any path that is not a critical path and thus takes less effort to complete than the critical path. Non-critical task (non-critical activity) Any activity that resides on a non-critical path and not a critical path. These tasks may accept some delay in completion. Task Analysis & Scheduling 31

32 Critical Path Method (CPM) “The critical path method analyses the precedence of activities to predict the total project duration. The method calculates which sequence activities (path) has the least amount of flexibility ”  Quality Software Project Management, Futrell et. al. Task Analysis & Scheduling 32

33 Task Scheduling Forward-pass scheduling  Early start time (ES) and early finish (EF) Backward-pass scheduling  Late start (LS) and Late finish (LF) Slack time Task Analysis & Scheduling 33

34 Forward-pass scheduling TaskTasks precedence Task lengthEarliest possible start time (ES) Earliest possible finish time (EF) ANone90 BA5 CA7 DB,C11 ED8 9 914 916 27 35 Task Analysis & Scheduling 34

35 Backward-pass scheduling TaskTasks precedence Task lengthLate start time (ES) Late finish time (EF) ANone9 BA5 CA7 DB,C11 ED8 9 16 9 27 35 0 Task Analysis & Scheduling 35

36 Slack time Total slack time of an activity  The difference in start time between a non-critical task’s late start time and its early start time or its late finish time and early finish time. Total slack time of a task = LS - ES Or Total slack time of a task = LF – EF e.g., Activity B: LS – ES (11 - 9) or LF – EF (16 - 14) => 2 Total slack time  The maximum allowable delay for all non-critical activities. Task Analysis & Scheduling 36

37 Program Evaluation and Review Technique (PERT) An estimating technique assumes each activity duration is subject to a range estimates uses weighting method to arrive at a specific duration. Task Analysis & Scheduling 37

38 Program Evaluation and Review Technique (PERT) Expected estimate (EE) = [O + P + (4 x A)] / 6 Where O = most optimistic estimate P = most pessimistic estimate A = most likely estimate Task Analysis & Scheduling 38

39 Program Evaluation and Review Technique (PERT) Expected Project time (EPT) Sum of expected estimates of the critical tasks. EPT = Σ (EE of all critical task) Task Analysis & Scheduling 39

40 CPM vs PERT Scheduling a lot of activities with 3 estimates computationally messy many people argue 3 estimates are not much more accurate than 1 estimate Most project management scheduling software use CPM Task Analysis & Scheduling 40


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