SWEN 256 Exam 2

Earned Value Tracking (how to use)

1) Establish a WBS to divide the project into parts 2) Identify the activities required for the current project 3) Allocate the effort required for each activity 4) Schedule the activities over time and resources 5) Analyze/review the schedule 6) Update the schedule by reporting activity progress 7) Enter the actual cost on the activities 8) Execute the Earned Value calculations 9) Analyze the data and make course corrections as necessary

How to Schedule

1) Identify what needs to be done (WBS) 2) Identify how much (size estimation) 3) Identify dependency between tasks (dependency graph, network diagram) 4) Estimate total duration of the work to be done (the actual schedule)

Verification

Are we building the product right?

Validation

Are we building the right product?

Estimation Methodology: Estimation by Analogy

Use past project (must be similar, find comparable attributes) Advantages: Based on actual historical data Disadvantages: Difficulty 'matching' project types. Prior data may have been mis-measured

Estimation Methodology: Expert Judgement

Use somebody who has recent experience on a similar project, "guesstimate". Accuracy depends on their "real" expertise

Tracking

Uses monitoring and tools to determine if plans, estimates, and schedules are accurate

Critical Path Method (CPM)

What is duration of the project? How much will the project be delayed if any one of the activities takes N days longer? Critical Path: Longest path in the precedence network (longest time) Critical Tasks: All tasks in the critical path

Partitioning a project

Decompose project into manageable chunks. All projects need this. Divide and Conquer. Two main causes of project failure: Forgetting something critical, ballpark estimates become targets

Errors

Defect prevention and Reduction: Human/Developer Error. In build time

Bugs

Defect prevention and Reduction: Software Defect. In build time

V&V confidence

Depends on systems purpose, user expectations, and marketing environment

Estimating

Determining the size and duration of activities

Agile Concepts

Embrace Change Frequent Delivery Simple Design Refactoring Pair Programming Retrospective Tacit Knowledge Test-Driven Development Dynamic Requirements, active customer involvement, and incremental delivery

Product WBS

Entity oriented, typically used by engineering manager

(Estimation) Effort

Expressed in man-months

Failure

Fault detection and containment: System Failure. in run time

Fault

Fault detection and containment: System fault. In run time

Work Breakdown Structure (WBS)

A checklist of the work that must be accomplished to met the project objectives, lists major project outputs and those departments or individuals responsible for their completion

Gantt Chart

A means of displaying simple activities or events plotted against time or dollars Advantages: Easy to understand, easy to change Disadvantages: Only a vague description of the project, does not always show interdependency of activities, may not show results of an early or late start of an activity

SCRUM: Story Point

A number that tells how the team how hard the story (think fibonacci sequence)

Process WBS

Activity oriented, typically used by Project Manager

Scheduling

Adds specific start and end dates, relationships, and resources

Testing

Assess and evaluate the quality of work performed at each step of the development process

Estimation Methodology: Top-down Estimation

Based on overall characteristics of project Advantages: Easy to calculate, effective early on Disadvantages: Some models are questionable or may not fit. Less accurate, doesn't look into details

Estimation Issues

Best estimates are based on past experience Overestimation issues: Project may not be funded, conservative estimates may mean 0 funding Parkenson's Law Danger of feature and scope creep Underestimation issues: Quality issues Inability to meet deadlines Morale and other team issues

(Estimation) COCOMO

COnstructive COst MOdel input: LOC, Output: man-months (effort) Cost drivers: motivation, ability of team, application experience Weakness: requires input of product size estimate in LOC

(Estimation) Code Reuse and Estimation

Code types: new modified and reused 50% modified is "new" Reused code takes 30% effort of new code Modified code takes 60% of new code Integration effort with reused code almost as expensive as with new code

Hybrid WBS

Combination of Process and Product WBS

Estimation Methodology: Bottom-up Estimation

Create WBS (work breakdown structure), identify individual tasks to be done Advantages: Works well if activities well understood Disadvantages: Specific activities not always known, more time consuming

Estimation Methodology: Wideband Delphi

Group consensus approach Advantages: Easy, inexpensive, utilizes expertise of several people. Doesn't require historical data Disadvantages: Difficult to repeat. May fail to reach consensus or reach the wrong one.

Planning

Identify activities. No specific start and end dates

Agile Manifesto

Individuals and Interactions - over process and tools Working software - over comprehensive documentation Customer collaboration - over contract negotiation Responding to change - over following a plan

Earned Value Tracking

Large tasks can/must be broken into subtasks Size tasks up to 80 man-hours; aim for 2 to 4 task completions per week

Estimation Methodology: Algorithmic Measures

Lines of Code (LOC) Function points feature points or object points

SCRUM: Velocity

Measure of the amount of work a team can tackle during a single sprint

SCRUM: Earned Value

Methodology to control a project. Provides a uniform and consistent measure for project progress Provides a basis for cost performance analysis on project

Process Methodology Spectrum

More Agile (to the left) Agile Methodologies: Scrum Crystal Lean, XP, DSDM, Feature Driven Design Less Agile (to the right) Plan Driven Methodologies: DSDM, Feature Driven Design, TSP, RUP, SW-CMM, PSP, Cleanroom, Inch-Pebble

V&V

Must be applied at each stage in the software process. Has two objectives: Discovery of defects in a system. Assessments of whether or not the system is usable in an operational situation

WBS Methodology

PM must map activities to chosen lifecycle Each lifecycle has different sets of activities Operations and maintenance phases are not normally in plan

PEST

Planning, Estimating, Scheduling, Tracking

Plan-Driven Concepts

Process Improvement Process Capability Organizational Maturity Process Group Risk Management Verification (building the product right) Validation (building the right product) System Architecture Think waterfall, but more incremental. Completeness of documentation important.

Student Syndrome

Procrastination until last minute (cram)

Quality Assurance

Software Engineering process improvement Fault tolerant software design All aspects of software verification and validation

Quality

Software Requirements: (the foundation from which quality is measured) How Software is Engineered: (specified standards define a set of criteria) Implicit Requirements: (example: good maintainability)

(Estimation) Function Points

Software size measured by number and complexity of functions it performs, more methodical than LOC. Example: House square feet = LOC # Bathrooms = function point

Quality and Testing

Testing is an aspect of quality, it is a measure of quality it does not deliver quality

WBS Techniques

Top-Down: Start at highest level and work down Bottom-Up: Start at lowest level tasks Analogy: Base WBS on similar project, use template Rolling Wave: (1st pass: go 1-3 levels deep, gather more requirements or data, add more detail later) Post-its on a wall All rely upon Expert Judgement

Software Estimation

Two types: Lucky or Lousy Created, used or refined during: Strategic planning, feasibility study and/or SOW, proposals, Vendor and sub-contractor evaluation, and project planning (iteratively) Basic Process: 1) Estimate the size of the product 2) Estimate the effort (man-months) 3) Estimate the schedule

Parkinson's Law

Work expands to take the time allowed

PERT

r --A,M,B--> S A = most optimistic time M = Most likely time B = most pessimistic time Expected time = (a + 4m + b) /6