課件教程分析

YanTheSchoolofSoftwareandPekingUniversityNo.24JinYuanRD,Beijing1-教員信1-進(jìn)度安8:301-成績考1-分組項(xiàng)分小組進(jìn)行，討論基于WEB的 網(wǎng) 訂1-如：2012送餐系商 信息系小區(qū)門禁管理系旅游信息系未名信息終交KTV智能管理系消息推送系1-如：2013 百年講堂售票

1-如：2014資產(chǎn)管理系途汽車票銷售系高校二手交易考勤管理系基于射頻識(shí)別技術(shù)的結(jié)帳出口系移動(dòng)定位指揮調(diào)度系FlappySports辦公流程管理系1-分組項(xiàng)1、小組項(xiàng)目報(bào)告必須按小組協(xié)作完成，6～8人一組，第2次課后提各組組長和小組成 理解的基礎(chǔ)上,整理、提煉、驗(yàn)證并逐步闡述；4、文件命名規(guī)則：分組報(bào)告：Rpt-組號(hào)演示文檔：Rpt-組號(hào).ppt1-

參考KarlE.Wiegers著 Software 1-參考書

參考1.IanK.Bray著，需求工程導(dǎo)引，AnIntroductiontoRequirementsEngineering，人民郵電 2.GeriSchneiderandJasonP.Winters著,姚 1- 在“0B304軟件需求工程 中 1-LectureLecture

IntroductiontosoftwareRequirements 14-09-GoodPracticesforRequirements 14-09-LectureLectureLectureLectureLectureLectureLecture

RequirementsElicitation RequirementsSpecificationProjectandDiscussion(1)RequirementsValidation

14-09-14-10-14-10-14-10-14-11-14-11-14-11-Lecture10:ProjectandLecture11:PracticesandLecture12:

14-11-14-12-14-12-

1-LectureLecture

IntroductiontosoftwareRequirements 14-09-GoodPracticesforRequirements 14-09-LectureLectureLectureLectureLectureLectureLecture

RequirementsElicitation RequirementsSpecificationProjectandDiscussion(1)RequirementsValidation

14-09-14-10-14-10-14-10-14-11-14-11-14-11-Lecture10:ProjectandLecture11:PracticesandLecture12:

14-11-14-12-14-12-

1-Understandsomekeytermsusedinsoftwarerequirementsengineering.Distinguishrequirementsdevelopmentfromrequirementsmanagement.Bealerttosomerequirements-relatedproblemsthatcanarise.LearnseveralcharacteristicsofexcellentUnderstandSign-Offof1-軟件需求工程真的有必要嗎兩個(gè)例1-RequirementLevelsofRequirementsDevelopmentandCharacteristicsofExcellentRequirementsfromtheWhatAboutSign-1-(AnEmployee)wecan'tgetthesystemtoacceptthenamechange.Itlookslikewecanchangeanameonlyifsomeone'smaritalstatus

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1-WhathappenedintheTheproblemareasmightinformalinformationimpliederroneous municated ydefinedrequirements,acasualchange1-WhathappenedintheErrorsmadeduringtherequirementsstageaccountfor40to60percentofalldefectsfoundinasoftwareprojectDavis1993;LeffingwellThetwomostfrequentlyreportedproblemsinalargesurveyoftheEuropeansoftwareindustryconcernedspecifyingandmanagingcustomerESPITI1995(EuropeanSoftwareProcessImprovementTrainingInitiative.UserSurveyReport).1-Themythicalman-NoSilverBullet:EssenceandAccidentsofSoftwareEngineering----Frederick1-5點(diǎn)事1-5點(diǎn)事 1-5點(diǎn)事 研究從20世紀(jì)70年代起就對(duì)軟件開發(fā)技術(shù)不斷地進(jìn)行研究。他們對(duì)A—7E機(jī)上的操作49％不正確的事實(shí)，31％疏忽，l3％不一致，5％二1-5點(diǎn)事1-事實(shí)結(jié)1-Whyso 1-Nowheremorethanintherequirementsprocessdotheinterestsofallthestakeholdersinasoftwareorsystemprojectintersect.Thesestakeholdersinclude:ation

ProjectLegalManufacturingSales,marketing,fieldsupport,helpdesk,andOtherpeoplewhowillhavetoworkwiththeproductandits1-AskYourselfTheproject'svisionandscopeareneverclearlyCustomersaretoobusytospendtimeworking ystsordevelopersontherequirements.Usersurrogates,suchasproductmanagers,developmentmanagers,usermanagers,ormarketers,claimtospeakfortheusers,buttheydon'taccura yrepresentuserneeds.Requirementsexistintheheadsof"theexperts"inyourorganizationandareneverwrittendown.1-AskYourselfif?Customersclaimthatallrequirementsarecritical,sotheydon'tprioritizethem.Developersencounterambiguitiesandmissinginformationwhencoding,sotheyhavetoguess.CommunicationsbetweendevelopersandcustomersfocusonuserinterfacedisplaysandnotonwhattheusersneedtodowiththeYourcustomerssignoffontherequirementsandthenchangethemcontinuously.1-AskYourselfif?Theprojectscopeincreaseswhenyouacceptrequirementschanges,butthescheduleslipsbecausenoadditionalresourcesareprovidedandnofunctionalityisremoved.Requestedrequirementschangesgetlost,andyouandyourcustomersdon'tknowthestatusofallchangerequests.Customersrequestcertainfunctionalityanddevelopersbuildit,butnooneeverusesit.Thespecificationissatisfied,butthecustomeris1-LevelsofRequirementsDevelopmentandCharacteristicsofExcellentRequirementsfromtheWhatAboutSign-1-RequirementTheIEEEStandardGlossaryofSoftwareEngineeringTerminology(1990)definesarequirementasAconditionorcapabilityneededbyausertosolveaproblemorachieveanobjective.Aconditionorcapabilitythatmustbemetorpossessedbyasystemorsystemcomponenttosatisfyacontract,standard,specification,orotherformallyimposed edrepresentationofaconditionorcapabilityasin1or2.1-DiversityoftheThediversityofrequirementstypes(SommervilleandSawyer1997):Requirementsare…aspecificationofwhatshouldbeimplemented.Theyaredescriptionsofhowthesystemshouldbehave,orofasystempropertyorattribute.Theymaybeaconstraintonthedevelopmentprocessofthe1-RequirementDefinitionLevelsofRequirementsRequirementsDevelopmentandCharacteristicsofExcellentRequirementsfromtheWhatAboutSign-1-Levelsoftypesoftypesof(diagrams,or1-LevelsofRequirementsSoftwarerequirementsincludethreedistinctlevels—businessrequirements,userrequirements,andfunctionalInaddition,everysystemhasanassortmentofnonfunctionalrequirements.1-BusinessBusinessrequirementsrepresenthigh-levelobjectivesoftheorganizationorcustomerwhorequeststhesystem.Businessrequirementstypicallycomefromthefundingsponsorforaproject,theacquiringcustomer,themanageroftheactualusers,themarketingdepartment,oraproductvisionary.Businessrequirementsdescribewhytheorganizationisimplementingthesystem—theobjectivestheorganizationhopestoachieve.1-BusinessrequirementsThebusinessrequirementscanberecordedinavisionandscope sometimescalledaprojectcharteroramarketrequirements Definingtheprojectscopeisthefirststepincontrollingthecommonproblemofscopecreep./1-UserUserrequirementsdescribeusergoalsortasksthattheusersmustbeabletoperformwiththeValuablewaystorepresentuserrequirementsincludeusecases,scenariodescriptions,andevent-responseUserrequirementsthereforedescribewhattheuserwillbeabletodowiththesystem.Anexampleofausecaseis"MakeaReservation"usinganairline,arentalcar,orahoWebsite./1-FunctionalFunctionalrequirementsspecifythesoftwarefunctionalitythatthedevelopersmustbuildintotheproducttoenableusersto plishtheirtasks,therebysatisfyingthebusinessSometimescalledbehavioralrequirements,thesearethetraditional"shall"statements:"Thesystemshalle-mailareservationconfirmationtotheuser."Functionalrequirementsdescribewhatthedeveloperneedstoimplement./1-SystemThetermsystemrequirementsdescribesthetop-levelrequirementsforaproductthatcontainsmultiplesubsystems—thatis,asystem(IEEE1998c).Asystemcanbeallsoftwareoritcanincludebothsoftwareandhardwaresubsystems.Peopleareapartofasystem,too,socertainsystemfunctionsmightbeallocatedtohuman1-Functionalrequirementsare edinasoftwarerequirementsspecification(SRS),whichdescribesasfullyasnecessarytheexpectedbehaviorofthesoftwareTheSRSisreferredtoasa ,althoughitcanbeadatabaseorspreadsheetthatcontainstherequirements,informationstoredinacommercialrequirementsmanagementtoolorperhapsevenastackofindexcardsforasmallproject.TheSRSisusedindevelopment,testing,qualityassurance,projectmanagement,andrelatedprojectfunctions./1-NonfunctionalInadditiontothefunctionalrequirements,theSRScontainsnonfunctionalrequirements.Qualityattributesaugmentthedescriptionoftheproduct'sfunctionalitybydescribingtheproduct'scharacteristicswhichincludeusability,portability,integrity,efficiency,androbustness.Othernonfunctionalrequirementsdescribeexternalinterfacesbetweenthesystemandtheoutsideworld,anddesignandimplementationconstraints.Constraintsimposerestrictionsonthechoicesavailabletothedeveloperfordesignandconstructionoftheproduct./1-BusinessBusinessrulesincludecorporatepolicies,ernmentregulations,industrystandards,accountingpractices,andcomputationalBusinessrulesarenotthemselvessoftwarerequirementsbecausetheyexistoutsidetheboundariesofanyspecificsoftwaresystem.However,theyoftenrestrictwhocanperformcertainusecasesortheydictatethatthesystemmustcontainfunctionalitytocomplywiththepertinentrules.1-BusinessrulesSometimesbusinessrulesaretheoriginofspecificqualityattributesthatareimplementedinfunctionality.Therefore,youcantracethegenesisofcertainfunctionalrequirementsbacktoaparticularbusinessrule./1-AfeatureisasetoflogicallyrelatedfunctionalrequirementsthatprovidesacapabilitytotheuserandenablesthesatisfactionofabusinessInthecommercialsoftwarearena,afeatureisagroupofrequirementsrecognizabletoastakeholderthataidsinmakingapurchasedecision—abulletitemintheproductdescription.Acustomer'slistofdesiredproductfeaturesisnotequivalenttoadescriptionoftheuser'stask-related1-FeatureWebbrowserfavoritesorbookmarks,spellcheck,macrorecording,automobilepowerwindows,onlineupdateoftaxcodechanges, ephonespeed-dialing,andautomatic signatureupdatingareexamplesofproductfeatures.Afeaturecan passmultipleusecases,andeachusecaserequiresthatmultiplefunctionalrequirementsbeimplementedtoallowtheusertoperformthetask./1-Abusinessrequirementmightread,"Theproductwillallowuserstocorrectspellingerrorsina Theproduct'sboxcoverannouncesthataspellcheckerisincludedasafeaturethatsatisfiesthisbusinessrequirement.Correspondinguserrequirementsmightincludetasks—usecases—suchas"Findspellingerrors"and"Addwordtoglobal1-ExamplesThespellcheckerhasmanyindividualfunctionalrequirements,whichdealwithoperationssuchasfindingandhighlightingamisspelledword,displayingadialogboxwithsuggestedreplacements,andgloballyreplacingmisspelledwordswithcorrectedwords.Thequalityattributecalledusabilitywouldspecifyjustwhatismeantbytheword"efficiently"inthebusinessrequirement./1-WhodoManagersormarketingdefinethebusinessrequirementsforsoftwarethatwillhelptheirOperatemoreefficiently(forinformationsystems)Competesuccessfullyinthemarketplace(forcommercialproducts).Theuserrequirementspermittheysttoderivethebitsoffunctionalitythatwilllettheusersperformtheirtaskswiththeproduct.Alluserrequirementsmustalignwiththebusiness1-WhodoWhat?DevelopersusethefunctionalandnonfunctionalrequirementstoDesignsolutionsthatimplementthenecessaryfunctionalityandAchievethespecifiedqualityandperformanceobjectives,withinthelimitsthattheconstraints1-NoAssumedIfyoudon'twritedowneventheimplicitandassumedrequirements,don'tbesurprisedifthesoftwaredoesn'tmeetuserexpectations.Ifyoucomeacrossanassumptionduringrequirementsdiscussions,writeitdownandconfirmitsaccuracy.Ifyou'redevelo areplacementsystem,reviewtheprevioussystemfeaturestodeterminewhetherthey'rerequiredinthereplacementratherthanassumingthattheyareorarenot./1-WhatRequirementsAreRequirementsspecificationsdonotincludedesignorimplementationdetails(otherthanknownconstraints),projectplanninginformation,ortestingSeparatesuchitemsfromtherequirementssothattherequirementsactivitiescanfocusonunderstandingwhattheteamintendsto1-WhatRequirementsAreNotProjectstypicallyhaveotherkindsofrequirements,includingdevelopmentenvironmentscheduleorbudgettheneedforatutorialtohelpnewusersgetuptospeed,orrequirementsforreleasingaproductandmovingitintothesupportenvironment.1-WhatRequirementsAreNotTheseareprojectrequirementsbutnotproductrequirements;theydon'tfallwithinthescopeofwhatwe’regoingtocover./*1-RequirementLevelsofRequirementsDevelopmentandCharacteristicsofExcellentRequirementsfromtheWhatAboutSign-1-Splitthe ofsoftwarerequirementsengineeringintorequirementsdevelopmentandrequirementsmanagement1-RequirementsWecanfurthersubdividerequirementsdevelopmentintoelicitation, specification,andvalidation.Thesesubdisciplines passalltheactivitiesinvolvedwithgathering,evaluating,and ingtherequirementsforasoftwareorsoftware-containingproduct.1-Identifyingtheproduct'sexpecteduserElicitingneedsfromindividualswhorepresenteachuserclassUnderstandingusertasksandgoalsandthebusinessobjectiveswithwhichthosetasksalign1-Activities(cont’d) yzingtheinformationreceivedfromuserstodistinguishtheirtaskgoalsfromfunctionalrequirements,nonfunctionalrequirements,businessrules,suggestedsolutions,andextraneousinformationAllocatingportionsofthetop-levelrequirementstosoftwarecomponentsdefinedinthesystemUnderstandingtherelativeimportanceofquality1-Activities(cont’d)NegotiatingimplementationTranslatingthecollecteduserneedsintowrittenrequirementsspecificationsandReviewingthe edrequirementstoensureacommonunderstandingoftheusers'statedrequirementsandtocorrectanyproblemsbeforethedevelopmentgroupacceptsthem/1-RequirementsRequirementsmanagemententails"establishingandmaintaininganagreementwiththecustomerontherequirementsforthesoftwareThatagreementisembodiedinthewrittenrequirementsspecificationsandthemodels.Customeracceptanceisonlyhalftheequationneededforrequirementsapproval.Thedevelopersalsomustacceptthespecificationsandagreetobuildthemintoa1-Definingtherequirementsbaseline(asnapshotintimerepresentingthecurrentlyagreed-uponbodyofrequirementsforaspecificrelease)ReviewingproposedrequirementschangesandevaluatingthelikelyimpactofeachchangebeforeapprovingitIncorporatingapprovedrequirementschangesintotheprojectinacontrolledway projectplanscurrentwiththe1-Activities(cont’d)NegotiatingnewcommitmentsbasedontheestimatedimpactofrequirementsTracingindividualrequirementstotheircorrespondingdesigns,sourcecode,andtestcasesTrackingrequirementsstatusandchangeactivitythroughouttheproject/1-TheBetweenrequirementsdevelopmentandrequirements1-BadThemajorconsequenceofrequirementsproblemsisrework— ngoversomethingthatyouthoughtwasalreadydone.Reworkcanconsume30to50percentofyourtotaldevelopmentcostandrequirementserrorsaccountfor70to85percentofthereworkcost.1-BadRequirementsItcostsfarmoretocorrectadefectthat'sfoundlateintheprojectthantofixitshortlyafteritscreation(Grady1-RequirementsInsufficientUser UserAmbiguousGoldMinimalOverlookedUserInaccurate1-BenefitsfromaHigh-QualityRequirementsProcessFewerrequirementsReduceddevelopmentFewerunnecessaryLowerenhancementFaster ReducedscopeReducedprojectMoreaccuratesystem-testingHighercustomerandteammember1-RequirementLevelsofRequirementsDevelopmentandManagementCharacteristicsofExcellentRequirementsRequirementsfromtheWhatAboutSign-1-CharacteristicsofExcellentRequirementStatement1-CharacteristicsofExcellentRequirements(cont’d)1-Eachrequirementmustfullydescribethefunctionalitytobedelivered.Ifyouknowyou'relackingcertaininformation,useTBD(tobedetermined)asastandardflagtohighlightthesegaps.Eachrequirementmustaccura ydescribethefunctionalitytobebuilt.1-Characteristics(cont’d)ItmustbepossibletoimplementeachrequirementwithintheknowncapabilitiesandlimitationsofthesystemanditsoperatingEachrequirementshould capabilitythatthecustomersreallyneedoronethat'srequiredforconformancetoanexternalsystemrequirementorastandard.1-Characteristics(cont’d)Assignanimplementationprioritytoeachfunctionalrequirement,feature,orusecasetoindicatehowessentialitistoaparticularproductrelease.Writerequirementsinsimple,concise,straightforwardlanguageappropriatetotheuser Defineallspecializedtermsandtermsthatmightconfusereadersinaglossary.1-Characteristics(cont’d)Seewhetheryoucandeviseafewtestsoruseotherverificationapproaches,suchasinspectionordemonstration,todeterminewhethertheproductproperlyimplementseachrequirement.1-Norequirementsornecessaryinformationshouldbeabsent.Consistentrequirementsdon't otherrequirementsofthesametypeorwithhigher-levelbusiness,system,oruser1-Characteristics(cont’d)YoumustbeabletorevisetheSRSwhennecessaryandtomaintainahistoryofchangesmadetoeachrequirement.Atraceablerequirementcanbelinkedbackwardtoitsoriginandforwardtothedesignelementsandsourcecodethatimplementitandtothetestcasesthatverifytheimplementationascorrect./*1-RequirementLevelsofRequirementsDevelopmentandCharacteristicsofExcellentRequirementsRequirementsfromtheCustomer'sWhatAboutSign-1-RequirementsfromtheWhoistheInthebroadestsense,acustomerisanindividualororganizationwhoderiveseitherdirectorindirectbenefitfromaproduct.Softwarecustomersincludethoseprojectstakeholderswhorequest,payfor,select,specify,use,orreceivetheoutputgeneratedbyasoftwareBytheway,otherprojectstakeholdersinclude ysts,developers,testers,ationwriters,projectmanagers,supportstaff,legalstaff,andmarketingstaff.1-Excellentsoftwareproductsaretheresultofawell-executeddesignbasedonexcellentrequirements.High-qualityrequirementsresultfromeffectivecommunicationandcollaborationbetweendevelopersandcustomers—a1-RequirementsBillofRightsforSoftwareCustomers yststospeakyour yststolearnaboutyourbusinessandyourobjectivesforthe yststostructuretheinformationyoupresentduringrequirementselicitationintoawrittensoftwarerequirementsspecification.1-RequirementsBillofRightsforSoftwareCustomers(cont’d) ystsanddevelopersprovideideasandalternativesbothforyourrequirementsandforimplementationoftheproduct.Describecharacteristicsoftheproductthatwillmakeiteasyandenjoyabletouse. ystsanddeveloperstotreatyouwithrespectandtomaintainacollaborativeandprofessionalattitudethroughoutyour1-RequirementsBillofRightsforSoftwareCustomers(cont’d)Begivenopportunitiestoadjustyourrequirementstopermitreuseofexistingsoftwarecomponents.Receivegood-faithestimatesofthecosts,impacts,andtrade-offswhenyourequestachangeintherequirements.Receiveasystemthatmeetsyourfunctionalandqualityneeds,totheextentthatthoseneedshavebeencommunicatedtothedevelopersandagreedupon.1-RequirementsBillofResponsibilitiesforSoftwareCustomers ystsanddevelopersaboutyourbusinessanddefinebusinessSpendthetimethatittakestoproviderequirements,clarifythem,anditerativelyfleshthemout.Bespecificandprecisewhenprovidinginputaboutthesystem'srequirements.1-RequirementsBillofResponsibilitiesforSoftwareCustomers(cont’d)Maketimelydecisionsaboutrequirementswhenrequestedtodoso.Respectadeveloper'sassessmentofthecostandfeasibilityofrequirements.Incollaborationwiththedevelopers,setprioritiesforfunctionalrequirements,systemfeatures,orusecases.1-RequirementsBillofResponsibilitiesforSoftwareCustomers(cont’d)Reviewrequirements sandevaluateCommunicatechangestotherequirementsassoonasyouknowaboutthem.Followthedevelopmentorganization'sprocessforrequestingrequirementschanges.Respecttheprocessesthe ystsuseforrequirementsengineering.1-RequirementLevelsofRequirementsDevelopmentandCharacteristicsofExcellentRequirementsfromtheWhatAboutSign-1-WhatAboutSign-Reachingagreementontherequirementsfortheproductto