Análise de Sistemas de Informação (ASI)ngarcia/aulas/asi1213/UBI ASI 1213 aula 6.pdf · Análise...

JoãoPauloFernandes,[email protected],[email protected]

AnálisedeSistemasdeInformação(ASI)

AnoLecFvo2012/2013*1ºSemestre

MestradoemEngenhariaInformáFca

UNIVERSIDADEDABEIRAINTERIORFaculdadedeEngenhariaDepartamentodeInformáFca JoãoPauloFernandes,[email protected]

Aula6

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Previously...

Contentadaptedfrom

SystemsAnalysisandDesignwithUML,4thEdiFonInternaFonalStudentVersion

AlanDennis,BarbaraHaleyWixomandDavidTegarden,

Wiley,2012


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SystemsDevelopmentLifeCycle(SDLC)

Planning

Analysis

Design

ImplementaFon



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SDLC:TheAnalysisPhase

QuesFonstobeAnsweredWhowilluseit?

Whatshouldthesystemdoforus?

Where&whenwillitbeused?

ThelineseparaFngAnalysisandDesignisblurry:deliverablesoftheanalysisphaseareactuallythefirststepofthedesignphase



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SDLC:TheAnalysisPhase

ThesystemsdevelopmentprocesstransformstheexisFng(asis)systemintotheproposed(tobe)system

Oneoutputofplanningisasystemrequest,whichprovidesgeneralideasfortheto‐besystem,definesthe

projectscopeandprovidesaniniFalworkplan

Analysistakesthegeneralideasinthesystemrequestandrefinesthemintoadetailedrequirementsdefini6on,

funcFonalmodels,structuralmodelsandbehavioralmodelsthattogetherformthesystemproposal


TheAnalysisPhase:RequirementsDeterminaFon

Contentadaptedfrom

SystemsAnalysisandDesignwithUML,4thEdiFonInternaFonalStudentVersion

AlanDennis,BarbaraHaleyWixomandDavidTegarden,

Wiley,2012


6



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RequirementsDeterminaFon

Turnhigh‐levelbusinessrequirementsintopreciserequirementsthatcanbeusedasinputstotherestofanalysis

ThesinglemostcriFcalstepoftheenFreSDLC

Changescanbemadeeasilyinthisstage

Most(>50%)systemfailuresareduetoproblemswithrequirements

TheiteraFveprocessofOOSADiseffecFvebecause:SmallbatchesofrequirementscanbeidenFfiedandimplementedincrementallyThesystemwillevolveoverFme



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Theblindmenandtheelephant

Themostdifficultaspectofdeterminingtheactualrequirementsisanalogoustothestoryoftheblindmenandtheelephant

Moral:

Soo1enintheologicwars,

Thedisputants,Iween,

Railonu<erignorance

Ofwhateachothermean,

AnprateaboutanElephant

Notoneofthemhasseen!

‐JohnGodfreySaxe



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RequirementsDeterminaFon

Purpose:toconverthighlevelbusinessrequirements(fromthesystemrequest)intodetailedrequirementsthatcanbeusedasinputsforcreaFngmodels

Whatisarequirement?AstatementofwhatthesystemmustdooracharacterisFcitmusthaveWilllaterevolveintoatechnicaldescripFonofhowthesystemwillbeimplemented

Types:FuncFonal:relatestoaprocessordataNon‐funcFonal:relatestoperformanceorusability



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NonfuncFonalRequirements

Requirementtype Example

OperaFonal • Thesystemshouldbeabletofitinapocketorpurse• ThesystemshouldbeabletointegratewiththeexisFnginventorysystem.

Performance • AnyinteracFonbetweentheuserandthesystemshouldnotexceed2seconds.

• ThesystemshouldreceiveupdatedinventoryinformaFonevery15minutes.

Security • Onlydirectmanagerscanseepersonnelrecordsofstaff• Customerscanseetheirorderhistoryonlyduringbusinesshours.

Cultural&PoliFcal • ThesystemshouldbeabletodisFnguishbetweenUnitedStatesandEuropeancurrency

• Thesystemshallcomplywithinsuranceindustrystandards.



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IgnoringNon‐funcFonalrequirementsIonceworkedonaconsulHngprojectinwhichmymanagercreatedarequirementsdefiniHonwithoutlisHngnon‐funcHonalrequirements.TheprojectwasthenesHmatedbasedontherequirementsdefiniHonandsold to the client for $5,000.Inmymanager’smind,thesystemthatwewouldbuildfortheclientwouldbeaverysimplestand‐alonesystemrunningoncurrenttechnology.It shouldn’t take more than a week to analyze, design, and build. Unfortunately,theclientshadotherideas.Theywantedthesystemtobeusedbymanypeopleinthreedifferentdepartments,andtheywantedtheabilityforanynumberofpeopletoworkonthesystemconcurrently.ThetechnologytheyhadinplacewasanHquated;nonetheless,theywantedthesystemtoruneffecHvelyontheexisHngequipment.Becausewedidn’tsettheprojectscopeproperlybyincludingourassumpHonsaboutnon‐funcHonalrequirementsintherequirementsdefiniHon,webasicallyhadtodowhatevertheywanted.ThecapabiliHtestheywantedtookweekstodesignandprogram. The project ended up taking four monthsandthe final project cost was $250,000.Ourcompanyhadtopickupthetabforeverythingexcepttheagreed‐upon$5,000.ThiswasbyfarthemostfrustaHngprojectsituaHonIeverexperienced.

‐BarbaraWixom



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IdenFfyingRequirementsOneofthemostcommonmistakesbynewanalystsistoconfusefuncFonalandnon‐funcFonalrequirements.Pretendthatyoureceivethefollowinglistofrequirementsforasalessystem.Thesystemshould: 1.beaccessibletowebusers 2.includethecompanystandardlogoandcolorscheme 3.restrictaccesstoprofitabilityinformaFon 4.includeactualandbudgetedcostinformaFon 5.providemanagementreports 6.includesalesinformaFonthatisupdatedatleastdaily 7.havetwo‐secondmaximumresponseFmeforpredefinedqueries 8.includeinformaFonfromallcompanysubsidiaries 9.printsubsidiaryreportsintheprimarylanguageofthesubsidiary 10.providemonthlyrankingsofsalespersonperformance

A.WhichrequirementsarefuncFonal? B.Whichrequirementsarenon‐funcFonal,andofwhatkind?



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RequirementsDefiniFonNon‐func6onal,Thesystem: Func6onal,Thesystemmust:

1.Opera6onalRequirements1.1willoperateinMSWindows1.2shouldconnecttoprinterswirelessly1.3shouldautomaFcallybackupattheend

ofeachday2.PerformanceRequirements2.1willstoreanewappointmentin2seconds2.2willretrievetheschedulesin2seconds3.SecurityRequirements3.1onlydoctorscansettheiravailability3.2onlyamanagercanproduceaschedule4.Culturalandpoli6calRequirements4.1NonehasbeenanFcipated

1.ManageAppointments1.1PaFentmakesnewappointment1.2PaFentchangesappointment1.3PaFentcancelsappointment2.ProduceSchedule2.1OfficeManagerchecksdaily

schedule2.2OfficeManagerprintsdailyschedule3.RecordDoctoravailability3.1Doctorupdatesschedule



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RequirementsDefiniFon

FuncFonal&non‐funcFonalrequirementslistedinoutlineformat

MaybeprioriFzed

ProvidesinformaFonneededinsubsequentworkflows

Definesthescopeofthesystem



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DeterminingRequirements

Requirementsarebestdeterminedbysystemsanalystsandbusinesspeopletogether

StrategiesforanalyzingtherequirementsBusinessProcessAnalysis(BPA)BusinessProcessImprovement(BPI)BusinessProcessReengineering(BPR)

TechniquesforidenFfyingrequirementsInterviews,quesFonnairesand/orobservaFonJointapplicaFondevelopment(JAD)Documentanalysis



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CreaFngaRequirementsDefiniFon

DeterminethetypesoffuncFonalandnon‐funcFonalrequirementsapplicabletotheproject

Userequirements‐gatheringtechniquestocollectdetailsAnalystsworkwithuserstoverify,changeandprioriFzeeachrequirement

ConFnuethisprocessthroughanalysisworkflow,butbecarefulofscopecreep

Requirementsthatmeetaneedbutarenotwithinthecurrentscopecanbeaddedtoalistoffutureenhancements



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ProblemsinRequirementsDeterminaFon

Analystmaynothaveaccesstothecorrectusers

RequirementsspecificaFonsmaybeinadequate

Somerequirementsmaynotbeknowninthebeginning

VerifyingandvalidaFngrequirementscanbedifficult


Summary


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SDLC,Theanalysisphase:

‐RequirementsDeterminaFon:

• definingarequirement

• requirementsdefiniFon

• determiningrequirements

• creaFngarequirementsdefiniFon

• real‐worldproblemswithrequirementsdeterminaFon

Análise de Sistemas de Informação (ASI)ngarcia/aulas/asi1213/UBI ASI 1213 aula 6.pdf · Análise...

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