Upload
avis-george
View
215
Download
2
Embed Size (px)
Citation preview
CSE Senior Design ICSE Senior Design I
Building a PlanBuilding a Plan
Instructor: Vassilis AthitsosInstructor: Vassilis Athitsos
Several of the slides in this module are a modification and amplification of Several of the slides in this module are a modification and amplification of slides prepared by Mr. Tom Rethard for use in a prior Senior Design Class. slides prepared by Mr. Tom Rethard for use in a prior Senior Design Class.
They were originally for use with They were originally for use with A Discipline for Software EngineeringA Discipline for Software Engineering (Watts (Watts S. Humphrey), sponsored by the U.S. Department of Defense. Original slides S. Humphrey), sponsored by the U.S. Department of Defense. Original slides
are copyright SEI; modifications are Copyright © 2002, T. Rethard. Further are copyright SEI; modifications are Copyright © 2002, T. Rethard. Further modifications by Mike O’Dell and Vassilis Athitsos. All Rights Reserved.modifications by Mike O’Dell and Vassilis Athitsos. All Rights Reserved.
1
CSE 4316 2
Why Plan?Why Plan?A plan helps you focusfocus on the goal
“Begin with the end in mind.1”A plan let’s you estimateestimate job completionA plan helps you track progresstrack progressA plan gives you milestonesmilestones that provide
a sense of accomplishment sense of accomplishment along the wayA plan helps you identify problems identify problems earlyA plan establishes commitments establishes commitments for the
team and each individual on it1 Stephen R. Covey, The Seven Habits of Highly Effective People
1
CSE 4316 3
What is a Plan?What is a Plan?
An agreement agreement by the team on the cost and schedule for a specified job
A structurestructure for organizing the workA frameworkframework for obtaining the required
resources (people, funds, etc.)A recordrecord of what was initially assumed
and committedIt’s a CONTRACTCONTRACT!
1
CSE 4316 4
Components of a PlanComponents of a PlanA LifecycleLifecycle Planning Model: The Master
Plan for the Project Order and criteria for key events Correct model for the job?
Work Estimate How big is the job (size and effort)? How long will it take, when will we finish?
Schedule and Work Breakdown When do we expect to have things done? What are we committing to?
1
CSE 4316 5
Selecting the Correct ModelSelecting the Correct Model
Discussion: Case Study 7.1 – Ineffective Lifecycle Model Selection Why was the model selected? What went wrong? What was the result? What might have been done differently?
1
CSE 4316 6
Representative Lifecycle Representative Lifecycle ModelsModels
Pure Waterfall (the old granddaddy) Code-and-Fix (and plan to fail)Spiral (new age sophistication)Modified Waterfalls (making the best of an
old standby)Evolutionary/Rapid Prototyping (design as
you go)Staged Models (show as you go)
Design to schedule
Hybrids – some combinationcombination of above
1
CSE 4316 7
Pure WaterfallPure WaterfallPhased deliverablesDocument-drivenDiscontinuous, inflexible phasesAll planning is done up frontGood for:
Well-defined, complex projectsQuality dominates cost and schedule
Not so good for:Projects where details cannot be completely specified up
frontRapid development projects
1
CSE 4316 8
Pure WaterfallPure Waterfall
RequirementsAnalysis
Concept & Planning
ArchitecturalDesign
DetailedDesign
Implementation& Debugging
SystemValidation
Pass
Fail
Pass
Pass
Pass
Pass
Fail
Fail
Fail
Fail
1
CSE 4316 9
Build (Code)-and-FixBuild (Code)-and-Fix In general, don’t do it!Process: Specify it, code-and-fix it, ship it(?)Advantages:
Low/no overhead (no planning, documentation, standards, etc.)
You can start TODAY! Requires little other than technical expertise
Disadvantages: No means of assessing progress, problems Dangerous! for other than tiny projects
1
CSE 4316 10
SpiralSpiral Risk-oriented, layered approach Process:
Break project into mini-projects, each addressing major risks, e.g. Risk of poor specifications Risk of poorly understood architecture
Iterate until risks are eliminated Six steps in each iteration
Advantages: Time and money can reduce risk
Disadvantages Complex
1
CSE 4316 11
SpiralSpiral
(Diagram from “Spiral Development: Experience, Principles and Refinements”, workshop paper by Barry Boehm)
Start
1
CSE 4316 12
Modified WaterfallsModified Waterfalls
Waterfall with Overlapping Phases (Sashimi) Like pure waterfall, but phases can overlap
Concept & Planning
RequirementsAnalysis
ArchitecturalDesign
DetailedDesign
Implementation& Debugging
SystemValidation
1
CSE 4316 13
Modified WaterfallsModified Waterfalls Waterfall with Subprojects
Begin detailed design on subprojects before overall architectural design is completeRequirements
Analysis
Concept & Planning
ArchitecturalDesign
DetailedDesign
Implementation& Debugging
SubSystemValidation System
Validation
DetailedDesign
Implementation& Debugging
SubSystemValidation
DetailedDesign
Implementation& Debugging
SubSystemValidation
DetailedDesign
Implementation& Debugging
SubSystemValidation
1
CSE 4316 14
Modified WaterfallsModified WaterfallsWaterfall with Risk Reduction
Spiral for requirements and architectural design phasesRequirements
Analysis
Concept & Planning
ArchitecturalDesign
DetailedDesign
Implementation& Debugging
SystemValidation
Generally, only for very large and complex projects
1
CSE 4316 15
Evolutionary (or Rapid) PrototypingEvolutionary (or Rapid) Prototyping
Especially useful when requirements are requirements are changing changing rapidly, or cannot be committed
Process: Design initial prototype of external/prominent
aspects Review with customer Iterate and refine until “good enough”
AdvantagesKeeps customer involved in processLow overhead
DisadvantagesImpossible to project schedule/budgetCan evolve to code-and-fix
1
CSE 4316 16
Staged Delivery ModelsStaged Delivery Models
Follow architectural design with staged design, implementation, test and delivery Staged delivery: iterate until done Design-to-schedule: iterate until scheduled
time Evolutionary delivery: Iterate with
customer feedback until done (Beta test approach)
1
CSE 4316 17
Hybrid Staged Delivery ModelHybrid Staged Delivery Model
RequirementsAnalysis
Concept & Planning
ArchitecturalDesign
Medium High Priority: Detailed design, implement and test
Medium Priority: Detailed design, implement and test
High Priority: Detailed design, implement and test
Medium Low Priority: Detailed design, implement and test
Low Priority: Detailed design, implement and test
Run out of time and money
Release
Design-to-Schedule Design-to-Schedule with risk reductionwith risk reduction((our model, approx.), approx.)
1
CSE 4316 18
Choosing the Right ModelChoosing the Right Model
Strengths and weaknesses analysis Discussion: Table 7-1
Case Study 7-2: Effective Lifecycle Model Selection Project characteristics Why was the model the right one? What was the outcome?
1
CSE 4316 19
Tools/Techniques to Help YouTools/Techniques to Help You
PERT and CPM Tools Program (or Project) Evaluation and Review
Technique Critical Path Method (from Dupont) Account for task dependencies Generally applies 3 separate estimates for
each task (shortest, nominal and longest) to calculate the expected effortIdentify longest/critical path(s)
1
CSE 4316 21
Tools/Techniques to Help YouTools/Techniques to Help You
CoCoMo (Constructive Cost Model) Estimating tool created by Barry Boehm
(Software Engineering Economics, 1981) Based on size, complexity, environment,
team composition, language, tools, etc. Method is based on a large study of varying
size significant projects.
1
CSE 4316 22
Work Breakdown StructureWork Breakdown StructureBreaks down the work to be done into
specific, product-oriented manageable unitsAllows development of a detailed plan
Basis for project cost and scheduleEnables assignment of responsibility
Provides basis for accountability of individualsDefines independent work units – minimum
interfacing with or dependency on other work units
Allows measurement of progress
1
CSE 4316 23
Work Breakdown StructureWork Breakdown Structure
WBS: Building WBS: Building a Bicyclea Bicycle
1
CSE 4316 24
Milestone Tracking - GANTTMilestone Tracking - GANTT
GANTT Chart Display Using MS Project
See Sample MS Project file on website.
1
CSE 4316 25
High Quality PlansHigh Quality Plans
Characteristics, as stated in the SEI text Complete Readily accessible, even by the customer Clear Specific Precise Accurate Measurable
1
CSE 4316 26
What’s makes a What’s makes a Good PlanGood Plan??
Complete Product SpecificationsA clear Statement of Work
Size estimate and scheduleSchedule for critical MilestonesA complete Work Breakdown StructureThe Processes/Procedures that you will
followIdentification of your Stakeholders
SRS…ADS/DDS
TIMELINE
MS PROJECT PLAN
PROJECTCHARTER
1
CSE 4316 27
What’s makes a What’s makes a Good PlanGood Plan??From the customer’s perspective:
Your commitment to deliver what is specified The quality level of the product A mechanism for participation/cooperation
Integrity and Openness
1
CSE 4316 28
Product SpecificationsProduct Specifications
Provide the details of whatwhat will be done: Requirements (SRS) Architecture (ADS) Detailed Design Documentation (more
of the howhow at this stage)Provides the basis for system testing
and acceptance
1
CSE 4316 29
MilestonesMilestonesDriven by the lifecycle model you use
Establishes start and stop dates for all key phases of project
Reinforced by your detailed schedules Use PERT/GANTT
Provides basis for measurement of progress Earned Value
Provides basis for identifying and estimating risks
Specifies critical deliverables ALL milestones have deliverables!
1
CSE 4316 30
Processes/ProceduresProcesses/Procedures
Defines howhow things will get done Provides the basis for establishing critical
milestones and deliverables Establishes entry and exit criteria for
critical phases Establishes the standards that will be used Defines the tools that are required to
complete the work