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Chapter 3Chapter 3Prescriptive Process ModelsPrescriptive Process Models

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Prescriptive ModelsPrescriptive Models

Prescriptive process models advocate an orderly approach Prescriptive process models advocate an orderly approach to software engineeringto software engineering

That leads to a few questions …That leads to a few questions … If prescriptive process models strive for structure and If prescriptive process models strive for structure and

order, order, are they inappropriate for a software world that are they inappropriate for a software world that thrives on change?thrives on change?

Yet, if we reject traditional process models (and the order Yet, if we reject traditional process models (and the order they imply) and replace them with something less they imply) and replace them with something less structured, structured, do we make it impossible to achieve do we make it impossible to achieve coordination and coherence in software work?coordination and coherence in software work?

Waterfall Waterfall ModelModel

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The Incremental The Incremental ModelModel

C o m m u n i c a t i o n

P l a n n i n g

M o d e l i n g

C o n s t r u c t i o n

D e p l o y m e n t

d e l i v e ry f e e d b a c k

analys is

des ign code

t es t

increment # 1

increment # 2

delivery of 1st increment

delivery of 2nd increment

delivery of nth increment

increment # n

project calendar time

C o m m u n i c a t i o nP l a n n i n g

M o d e l i n g

C o n s t r u c t i o n

De p l o y m e n t

d e l i v e r y

f e e d b a c k

analys is

des ign code

t es t

C o m m u n i c a t i o nP l a n n i n g

M o d e l i n g

C o n s t r u c t i o n

D e p l o y m e n t

d e l i v e r y

f e e d b a c k

analys is

des igncode t es t

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The RAD ModelThe RAD Model

Communication

Planning

Modelingbusiness modeling data modeling process modeling

Constructioncomponent reuse automatic code generation testing

Deployment

60 - 90 days

Team # 1

Modelingbusiness modeling

data modeling process modeling

Constructioncomponent reuse automatic code

generation test ing

Modelingbusiness modeling data modeling process modeling

Const ruct ioncomponent reuse automatic code generation testing

Team # 2

Team # n

integration delivery feedback

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Evolutionary Models: Evolutionary Models: PrototypingPrototyping

Communication

Quick plan

Construction of prototype

Modeling Quick design

Delivery & Feedback

Deployment

communication

Quickplan

ModelingQuick design

Constructionof prototype

Deploymentdelivery &feedback

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Evolutionary Models: The Evolutionary Models: The SpiralSpiral

communication

planning

modeling

constructiondeployment delivery feedback

start

analysis design

code test

estimation scheduling risk analysis

Spiral Model

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Evolutionary Models: ConcurrentEvolutionary Models: Concurrent

Under review

Baselined

Done

Under

revision

Awaiting

changes

Under

development

none

Modeling activity

represents the stateof a software engineeringactivity or task

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Still Other Process Still Other Process ModelsModels

Component based developmentComponent based development—the process to —the process to apply when reuse is a development objectiveapply when reuse is a development objective

Formal methodsFormal methods—emphasizes the mathematical —emphasizes the mathematical specification of requirementsspecification of requirements

AOSDAOSD—provides a process and methodological —provides a process and methodological approach for defining, specifying, designing, and approach for defining, specifying, designing, and constructing constructing aspectsaspects

Unified ProcessUnified Process—a “use-case driven, architecture-—a “use-case driven, architecture-centric, iterative and incremental” software process centric, iterative and incremental” software process closely aligned with the Unified Modeling Language closely aligned with the Unified Modeling Language (UML)(UML)

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inceptioninception

The Unified Process (UP)The Unified Process (UP)

software increment

Release

Inception

Elaboration

construction

transition

production

inception

elaboration

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UP PhasesUP Phases

Inception Elaboration Construction Transition Production

UP Phases

Workflows

Requirements

Analysis

Design

Implementation

Test

Iterations #1 #2 #n-1 #n

Support

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UP Work ProductsUP Work ProductsInception phase

Elaboration phase

Construction phase

Transition phase

Vision document Init ial use-case model Init ial project glossaryInit ial business case Init ial risk assessment. Project plan, phases and iterations. Business model, if necessary. One or more prototypes Incept io n

Use-case modelSupplementary requirements including non-functional Analysis model Software architecture Description. Executable architectural prototype. Preliminary design model Revised risk listProject plan including iteration plan adapted workflows milestones technical work products Preliminary user manual

Design modelSoftware components Integrated software increment Test plan and procedure Test cases Support documentation user manuals installat ion manuals description of current increment

Delivered software increment Beta test reports General user feedback