课件教程分析

YanTheSchoolofSoftwareandPekingUniversityNo.24JinYuanRD,Beijing1-教员信1-进度安8:301-成绩考1-分组项分小组进行，讨论基于WEB的 网 订1-如：2012送餐系商 信息系小区门禁管理系旅游信息系未名信息终交KTV智能管理系消息推送系1-如：2013 百年讲堂售票

1-如：2014资产管理系途汽车票销售系高校二手交易考勤管理系基于射频识别技术的结帐出口系移动定位指挥调度系FlappySports办公流程管理系1-分组项1、小组项目报告必须按小组协作完成，6～8人一组，第2次课后提各组组长和小组成 理解的基础上,整理、提炼、验证并逐步阐述；4、文件命名规则：分组报告：Rpt-组号演示文档：Rpt-组号.ppt1-

参考KarlE.Wiegers著 Software 1-参考书

参考1.IanK.Bray著，需求工程导引，AnIntroductiontoRequirementsEngineering，人民邮电 2.GeriSchneiderandJasonP.Winters著,姚 1- 在“0B304软件需求工程 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-软件需求工程真的有必要吗两个例1-RequirementLevelsofRequirementsDevelopmentandCharacteristicsofExcellentRequirementsfromtheWhatAboutSign-1-(AnEmployee)wecan'tgetthesystemtoacceptthenamechange.Itlookslikewecanchangeanameonlyifsomeone'smaritalstatus

Well,yeah.Idon'trememberyou lingmeaboutthispossibilitywhenwetalkedaboutthesystem.

PhoneResponse

1-WhathappenedintheTheproblemareasmightinformalinformationimpliederroneous municated ydefinedrequirements,acasualchange1-WhathappenedintheErrorsmadeduringtherequirementsstageaccountfor40to60percentofalldefectsfoundinasoftwareprojectDavis1993;LeffingwellThetwomostfrequentlyreportedproblemsinalargesurveyoftheEuropeansoftwareindustryconcernedspecifyingandmanagingcustomerESPITI1995(EuropeanSoftwareProcessImprovementTrainingInitiative.UserSurveyReport).1-Themythicalman-NoSilverBullet:EssenceandAccidentsofSoftwareEngineering----Frederick1-5点事1-5点事 1-5点事 研究从20世纪70年代起就对软件开发技术不断地进行研究。他们对A—7E机上的操作49％不正确的事实，31％疏忽，l3％不一致，5％二1-5点事1-事实结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