CEN 4021 4th Lecture
CEN 4021 CEN 4021 Software Engineering II Software Engineering II
Instructor: Masoud Sadjadi
http://www.cs.fiu.edu/~sadjadi/
Software Project Planning (POMA)Task Analysis
4th LectureCEN 4021: Software Engineering II
AcknowledgementsAcknowledgements
Dr. Onyeka Ezenwoye
Dr. Peter Clarke
2
4th LectureCEN 4021: Software Engineering II
AgendaAgenda
Software Project Planning (POMA)– Task Analysis
Work Breakdown Structure (WBS)
4th LectureCEN 4021: Software Engineering II
Work Breakdown Structure 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.
4th LectureCEN 4021: Software Engineering II
Work Breakdown StructureWork 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
4th LectureCEN 4021: Software Engineering II
Work Breakdown StructureWork 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.
4th LectureCEN 4021: Software Engineering II
Work Breakdown StructureWork 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
4th LectureCEN 4021: Software Engineering II
Identify and list all
deliverables
For each deliverable:Identify and list thenecessary tasks for
completing the deliverable
For each task:Compute the timelinerequired by dividingeffort 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 allthe ordered tasks need for
each deliverable
Perform task
After the timelinesfor all tasks for all
deliverable are computed
FlowFlow ofof WBSWBS toto scheduleschedule
4th LectureCEN 4021: Software Engineering II
WBS - ExampleWBS - 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
4th LectureCEN 4021: Software Engineering II
WBS - ExampleWBS - 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.
Choice of activities and sequence depends on:
1. The size and complexity of both the problem and the solution,
4th LectureCEN 4021: Software Engineering II
WBS - ExampleWBS - Example
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.
4th LectureCEN 4021: Software Engineering II
WBS Task RefinementWBS 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
4th LectureCEN 4021: Software Engineering II
WBS Task RefinementWBS Task Refinement
Refinement of activity A:
Table 2.1. Subtasks within the Design activity
Tasks Description
Task A-1 Overall application, user interface (UI), and message architecture
Task A-2 Database and relational tables design
Task A-3 Application function 1 design
Task A-4 Application function 2 design
Task A-5 Application function 3 design
4th LectureCEN 4021: Software Engineering II
WBS - Task SequencingWBS - 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.
4th LectureCEN 4021: Software Engineering II
WBS - Task SequencingWBS - 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.
4th LectureCEN 4021: Software Engineering II
WBS - Task SequencingWBS - Task Sequencing
TaskA-1
TaskA-2
TaskA-3
TaskA-4
TaskA-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.
4th LectureCEN 4021: Software Engineering II
WBS - Task SequencingWBS - 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
4th LectureCEN 4021: Software Engineering II
WBS – Time and Resource WBS – Time and Resource AssignmentsAssignments
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.
4th LectureCEN 4021: Software Engineering II
WBS – Time and Resource WBS – Time and Resource AssignmentsAssignments
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)
4th LectureCEN 4021: Software Engineering II
WBS - Time and Resource WBS - Time and Resource AssignmentsAssignments
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
4th LectureCEN 4021: Software Engineering II
WBS - Time and Resource WBS - Time and Resource AssignmentsAssignments
Units of tasks management:
Example of Historical Information
Tasks Possible rates
Requirements elicitation 2 interviews/person-day
Message design 15 messages/person-day
Code implementation 2 functions points/person-day; 40 lines of Java/person-day
Test generation 5 test scenarios/person-day
4th LectureCEN 4021: Software Engineering II
WBS - Time and Resource WBS - Time and Resource AssignmentsAssignments
TaskA-1
TaskA-2
TaskA-3
TaskA-4
TaskA-5
End
5 days
3 days
3 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.
4th LectureCEN 4021: Software Engineering II
WBS - Time and Resource WBS - Time and Resource AssignmentsAssignments
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.
4th LectureCEN 4021: Software Engineering II
WBS - Time and Resource WBS - Time and Resource AssignmentsAssignments
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.
4th LectureCEN 4021: Software Engineering II
WBS - Time and Resource WBS - Time and Resource AssignmentsAssignments
Estimates and assignments:
Subtasks with time Estimates and People Assignments
Subtask Person Sequence time-estimate
A-1 P1
A-2 P2
A-3 P3
A-4 P4
A-5 P5
5 days
3 days
7 days
2 days
5 days
4th LectureCEN 4021: Software Engineering II
WBS - Time and Resource WBS - Time and Resource AssignmentsAssignments
Milestones
Subtask Person Sequence time-estimate
A-1 P1
A-2 P2
A-3 P3
A-4 P4
A-5 P5
5 days
3 days
7 days
2 days
5 days
Minor Milestone Milestone
4th LectureCEN 4021: Software Engineering II
WBS - Time and Resource WBS - Time and Resource AssignmentsAssignments
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.
4th LectureCEN 4021: Software Engineering II
WBS - Time and Resource WBS - Time and Resource AssignmentsAssignments
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.
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