PROCESS MODELS.ppt

BHARATHIAR UNIVERSITY
B.Sc Computer Science
BCA
B.Sc Information Technology

1. Prepared by Dr.T.Thendral 06.07.2023

2. SDLC–SoftwareDevelopmentLifeCycle
Processmodelisaframeworkthatdescribesthe
activities,actions,tasks,milestonesandworkproducts
performedateachstageofasoftwaredevelopment
projectthatleadstoahighqualitysoftware
Prepared by Dr.T.Thendral 06.07.2023

3. Waterfall Model
Incremental process Models
◦Incremental model
◦RAD model
Evolutionary Process Models
◦Prototyping model
◦Spiral model
Object oriented process Model
Prepared by Dr.T.Thendral 06.07.2023

4. WATERFALL MODEL
Linear life cycle model orclassic life cycle model
Prepared by Dr.T.Thendral 06.07.2023

5. Prepared by Dr.T.Thendral 06.07.2023

6. Project initiation & requirement gathering
◦What is the Problem to Solve?
◦What Does Customer Need/Want?
◦Interactions Between SE and Customer
◦Identify and Document System Requirements
◦Generate User Manuals and Test Plans
•Planning
◦Prioritize the requirements
◦Plan the process
Prepared by Dr.T.Thendral 06.07.2023

7. Analysis and design
◦How is the Problem to be Solved?
◦High-Level Design
◦Determine Components/Modules
◦Transition to Detailed Design
◦Detail Functionality of Components/Modules
Coding and Testing
◦Writing Code to Meet Component/Module Design
Specifications
◦Individual Test Modules in Isolation
◦Integration of Components/Modules into Subsystems
◦Integration of Subsystems into Final Program
Prepared by Dr.T.Thendral 06.07.2023

8. Deployment
◦System Delivered to Customer/Market
◦Bug Fixes and Version Releases Over Time
Strengths
Easy to understand, easy to use
Provides structure to inexperienced staff
Milestones are well understood
Sets requirements stability
Good for management control (plan, staff, track)
Works well when quality is more important than
cost or schedule
Prepared by Dr.T.Thendral 06.07.2023

9. All projects cannot follow linear process
All requirements must be known upfront
Few business systems have stable
requirements
The customer must have patience
Aworkingversionoftheprogramwillnotbe
availableuntillateintheprojecttime-span
Leads to ‘blocking states’
Inappropriate to changes
Prepared by Dr.T.Thendral 06.07.2023

10. Requirements are very well known
Product definition is stable
Technology is understood
New version of an existing product
Porting an existing product to a new platform
Prepared by Dr.T.Thendral 06.07.2023

11. Combinestheelementsofwaterfallmodelinaniterative
fashion
Constructapartialimplementationofatotalsystem
Thenslowlyaddincreasedfunctionality
Userrequirementsareprioritisedandthehighestpriority
requirementsareincludedinearlyincrements
Eachsubsequentreleaseofthesystemaddsfunctiontothe
previousrelease,untilalldesignedfunctionalityhasbeen
implemented
Prepared by Dr.T.Thendral 06.07.2023

12. Prepared by Dr.T.Thendral
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13. Prepared by Dr.T.Thendral
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Communication, Planning,
Modeling(analysis,design),
Construction(code,test),
Deployment(delivery,feedback),

14. TheIncrementalApproachusesasetnumberofstepsand
developmentgoesfromstarttofinishinalinearpathof
progression.
TheIterativeApproachhasnosetnumberofsteps,rather
developmentisdoneincycles.
IncrementalModelisaprocessofsoftwaredevelopment
whererequirementsarebrokendownintomultiplestandalone
modulesofsoftwaredevelopmentcycle.
Incrementaldevelopmentisdoneinstepsfromanalysis
design,implementation,testing/verification,maintenance.
Prepared by Dr.T.Thendral
06.07.2023

15. Requiresgoodplanninganddesign
Requiresearlydefinitionofacompleteand
fullyfunctionalsystemtoallowforthe
definitionofincrements
Well-definedmoduleinterfacesarerequired
(somewillbedevelopedlongbeforeothers)
Totalcostofthecompletesystemisnotlower
Prepared by Dr.T.Thendral
06.07.2023

16. Whenstaffingisnotavailablebydeadline
Mostoftherequirementsareknownup-frontbutare
expectedtoevolveovertime
Whenthesoftwarecanbebrokenintoincrementsand
eachincrementrepresentasolution
Aneedtogetbasicfunctionalitytothemarketearly
Onprojectswhichhavelengthydevelopment
schedules
Onaprojectwithnewtechnology
Prepared by Dr.T.Thendral
06.07.2023

17. An incremental process model that emphasizes short
development cycle
“High-speed” adaptation of the waterfall model.
RAD approach also maps into the generic framework
activities
Prepared by Dr.T.Thendral
06.07.2023

18. Prepared by Dr.T.Thendral
06.07.2023

19. BusinessModeling-flowofinformationandthe
distributionofinformationbetweenvariousbusiness
channels.

20. TheinformationgatheredintheBusinessModeling
phaseisreviewedandanalyzedtoformsetsofdata
objectsvitalforthebusiness.
Theattributesofalldatasetsisidentifiedand
defined.
Therelationbetweenthesedataobjectsare
establishedanddefinedindetailinrelevancetothe
businessmodel.

21. ThedataobjectsetsdefinedintheDataModeling
phaseareconvertedtoestablishthebusiness
informationflowneededtoachievespecificbusiness
objectivesasperthebusinessmodel.
Theprocessmodelforanychangesorenhancements
tothedataobjectsetsisdefinedinthisphase.
Processdescriptionsforadding,deleting,retrieving
ormodifyingadataobjectaregiven.

22. Theactualsystemisbuiltandcodingisdoneby
usingautomationtoolstoconvertprocessanddata
modelsintoactualprototypes.
TestingandTurnover
TheoveralltestingtimeisreducedintheRADmodel
astheprototypesareindependentlytestedduring
everyiteration

23. Changingrequirementscanbeaccommodated
Progresscanbemeasured
IterationtimecanbeshortwithuseofpowerfulRADtools
Productivitywithfewerpeopleinashorttime
Reduceddevelopmenttime
Increasesreusabilityofcomponents
Quickinitialreviewsoccur
Encouragescustomerfeedback
Integrationfromverybeginningsolvesalotofintegration
issues

24. Requireshighlyskilleddevelopers/designers.
Highdependencyonmodelingskills.
Inapplicabletocheaperprojectsascostofmodelingand
automatedcodegenerationisveryhigh.
Managementcomplexityismore.
Suitableforsystemsthatarecomponentbasedand
scalable.
Requiresuserinvolvementthroughoutthelifecycle.
Suitableforprojectrequiringshorterdevelopmenttimes.

25. Forlargeprojects,RADrequiressufficienthuman
resourcestocreatetherightnumberofRADteams
Ifdevelopers&customersarenotcommittedto
rapid-fireactivities,RADprojectswillfail.
Ifthesystemcannotbeproperlymodularized,
buildingthecomponentswillbeproblematic
Ifhigh-performanceisanissue,RADmaynotwork.
RADmaybeinappropriatewhentechnicalrisksare
high
Prepared by Dr.T.Thendral 06.07.2023

26. Reasonably well-known requirements
User involved throughout the life cycle
Project can be time-boxed
Functionality delivered in increments
High performance not required
Low technical risks
System can be modularized
Prepared by Dr.T.Thendral
06.07.2023

27. These models produce an increasingly more
complete version of the software with each iteration
When to use
◦Tight market deadlines
◦Well defined system requirements
◦No details about system definition
Prepared by Dr.T.Thendral 06.07.2023

28. Aprototypeisapartiallydevelopedproductthat
enablescustomersanddeveloperstoexaminesome
aspectsoftheproposedsystemanddecideifitis
suitableorappropriateforthefinishedproduct
◦Startwithwhatisknownaboutrequirements
◦Doaquickdesign
◦Buildtheprototypebyfocusingonwhatwillbe
seenbytheuser
◦Usetheprototypetoshowtheuserandhelp
refiningrequirements
Prepared by Dr.T.Thendral 06.07.2023
PROTOTYPING MODEL

30. PROTOTYPING MODEL
Prepared by Dr.T.Thendral
06.07.2023

31. Step1:Requirementsgatheringandanalysis
Aprototypingmodelstartswithrequirementanalysis
Duringtheprocess,theusersofthesystemare
interviewedtoknowwhatistheirexpectationfrom
thesystem.
Step2:Quickdesign
Thesecondphaseisapreliminarydesignoraquick
design
Asimpledesignofthesystemiscreated
However,itisnotacompletedesign
Itgivesabriefideaofthesystemtotheuser
Thequickdesignhelpsindevelopingtheprototype

32. Step3:BuildaPrototype
Inthisphase,anactualprototypeisdesignedbasedonthe
informationgatheredfromquickdesign
Itisasmallworkingmodeloftherequiredsystem.
Step4:Initialuserevaluation
Inthisstage,theproposedsystemispresentedtotheclientfor
aninitialevaluation.
Ithelpstofindoutthestrengthandweaknessoftheworking
model.
Commentandsuggestionarecollectedfromthecustomerand
providedtothedeveloper.
Step5:Refiningprototype
Iftheuserisnothappywiththecurrentprototype,youneedto
refinetheprototypeaccordingtotheuser'sfeedbackand
suggestions.

33. Customerseeswhatappearstobeaworkingversionofthe
softwareandpresumesthatitisthefinalthing
Thedeveloperoftenmakesimplementationcompromisesin
ordertogetaprototypeworkingquickly
Onlyoneadvantageisactualsoftwareisengineered
withaneyetowardquality
Prepared by Dr.T.Thendral
06.07.2023

34. Itcouplestheiterativenatureofprototypingwiththe
controlledandsystematicaspectsofthewaterfallmodel
Process
Adaptedtocompletelifecycle
Processisrepresentedasaspiralratherthanasasequenceof
activitieswithbacktracking.
Eachloopinthespiralrepresentsaphaseintheprocess.
Nofixedphasessuchasspecificationordesign-loopsinthe
spiralarechosendependingonwhatisrequired.
Prepared by Dr.T.Thendral
06.07.2023

35. Prepared by Dr.T.Thendral
06.07.2023

36. Focusesattentiononreuseoptions
Focusesattentiononearlyerrorelimination
Putsqualityobjectivesupfront
Integratesdevelopmentandmaintenance
Providesaframeworkforhardware/softwareDevelopment
Prepared by Dr.T.Thendral
06.07.2023

37. Itmaybedifficulttoconvincecustomersthatthe
evolutionaryapproachiscontrollable
Itdemandsriskassessmentexpertiseandreliesonthis
expertiseforsuccess
Ifamajorriskisuncoveredandmanaged,problems
willoccur
Prepared by Dr.T.Thendral
06.07.2023

38. When creation of a prototype is appropriate
When costs and risk evaluation is important
For medium to high-risk projects
Long-term project commitment unwise because of
potential changes to economic priorities
Users are unsure of their needs
Requirements are complex
New product line
Significant changes are expected
Prepared by Dr.T.Thendral 06.07.2023