《高级软件工程》全册配套课件

《高级软件工程》全册配套课件Chapter0ThebriefintroductiontoAdvancedSoftwareEngineeringandTheCourseMyunderstandingaboutASE.engineeringsoftwareengineeringadvancedsoftwareengineeringThepurposeofthecourseHowtolearnthecourse?PrecedentcoursesReferenceScoreandevaluation1.MyunderstandingaboutASE

Engineering:Fiveimportantfeaturesofengineering(1)largeinthesize,

(2)involvelargeinvestment

(3)Needalotofpersonstotakepartin

(4)Needalongperiodtocomplete

(5)Needalotofauxiliaryequipments.toolsalotofcomponents,codesandstandardsEngineeringhasthousandshistory.TheGreatWallinChina(221B.C)TheGreatcanalinChina(581D.C)

ThePyramidsinEgypt(3000B.C)

TheThreeGorges

ProjectinChinaTheEiffleTowerinFrenchTheSydneyoperaHouse

inAustraliaSoftwareEngineering,NATO,1968,Forexample,largehousebuilding,bridgeEngineering,railwayengineering.LargescalewaterpowerprojectTheseprojectneedstandard，

organization,cooperation,criterion

Ifthesizeissmall,thecharactersforengineeringisnotevident,forexample,severalpeasantsbuildasmallhouse,severalmenbuiltadamonasmallstreamtomakewaterflowintoricefields.severalprogrammerscodeasmallsystem.SoftwareengineeringWhatissoftware?Softwaresystemsareprograms,usuallylargeones,runningonacomputer.Despiteseveraldecadesofconcertedeffort,thedesign,implementation,andmaintenance

ofsuchsystemsismoreofanartthanascience.Thatistosay,thedevelopmentandmaintenanceofsuchsystemsareprocessesdominatedbylooseguidelines,

heuristicprinciplesandinspirationalguesswork,ratherthanformallydefinedprinciplesandwelldefined

techniques.By:Partridge,Derek.Chicago:GlenlakePub.,Ltd.1998.SoftengineeringSoftware,codesanddocuments.Code,program,thekeyisthatitcontainknowledge,Softwareisthecrystalofknowledge,ittheknowledgewhichcanrunonthecomputer,andwecangettheanswerofaproblemeasilyandinstantly.AdvantagesofprogramItcanrunonthecomputer.Itisstrict,dealeverythingequallyandrationally,noinfluencebymoodofpeople.Softwareengineeringrequiresunderstandingandapplicationofengineeringprinciples,designskills,goodmanagementpractice,computerscienceandmathematicalformalism.Itisthetaskofsoftwareengineeringtodrawtogethertheseseparateareasofexpertiseandbringthemtobearupontherequirements,elicitation,specification,design,verification,implementation,testing,documentationandmaintenanceofcomplexandlargescalesoftwaresystems.Thesoftwareengineerthusfulfillstheroleofarchitectofacomplexsystem,takingaccountofuserrequirementsandneeds,feasibility,cost,quality,reliability,safetyandtimeconstraints.Thenecessitytobalancetherelativeimportanceofthesefactorsaccordingtothenatureofthesystemandaccordingtothenatureofthesystemandtheapplicationgivesastrongethicaldimensiontothetaskofthesoftwareengineer,onwhomthesafetyorwellbeingofothersmaydepend,andforwhom,asinmedicineorinlaw,asenseofprofessionalmoralityisarequirementofthejob.Soundengineeringjudgementisrequired.IEEreportonUndergraduateCurriculaforSoftwareengineering,June1989,London,p.13.

Softwareengineering,asciencewhichresearcheshowtomakesoftwaresystemswithhigherquality,highereffectiveness,andlowercost.SoftwarecrisesIfwedonotdealwiththeproductionofsoftwarewiththemodeofengineering,wewillsufferacriticaldamages.(1)Intheearly1980s,theUnitedStatesInternalRevenueService(IRS)hiredSperyCorporationtobuildanautomatedfederalincometaxformprocessingsystem,originalinvestmentis$103million.whentheprojectwascomplete,Itisfoundthat“thesystemhasprovedinadequatetotheworkloadandmustbereplacedsoon”In1985,anextra$90millionwasneedtoenhanced.Inaddition,becausetheIRSfromreturningrefundingtototaxpayers,wasforcedtopay$40.2millionininterest.$22.3millionwaspaidovertimewagestoitsemployees.Thereason:nomasterplan.onlyasixthousandspagetechnicaldocument.“$4billionfiascothatisfloundering”LosAngelesTime

(2)WashingtonPost,1996Pilot’sComputerErrorcitedinPlaneCrashAmericanAirlinesSaysOne-LetterCodeWasReasonJetHitMountaininColombiaThecrashkilledallbutfourofthe163peopleaboardThedestinationoftheplaneisCaliOnelettercodeforCaliisthesameastheoneforBogotaTheaviationcontrolsystemwrongtodirectthecaptaintoflytoBogota.(3)Thereisnogoodmethodtotesttoguaranteeadequatereliability.Anantiballisticmissilesystemrequireatleasttenmillionlinesofcodes.Sointhesystemteststagewerequirestotesttheenormousamountofcodes.Bythesafety-criticalstandard,thismeansthesystemcanfailnomoreoftenthanoncein109hoursofoperation.Wewouldtorunthesystemforatleast109hours,i.e.11400years!

Thefeaturesofsoftwareproductsthatisdifferentfromotherengineeringproducts,suchasbuilding,bridge,etc.(1)Itisdifficulttoreadandrevise.

Sothedocumentcompanyingprogramisveryimportant,isnecessary.(2)Thepeoplewhoattendtheengineeringarehigh

levelsoftwaredeveloper.

Sothismeanshigh

costforaproject.(3)SoftwareproductsareamentalproductsTheproductsofgeneralengineering:reformnature,offerpeopletheconvenienceoflifeandwork.Alargebuilding,alargebridge,alonghighrailway,alargedam,shaped.TheproductsSoftwareengineering:justofferonekindofproductsToolsofsubstitutionformentalactions.Problemsolvingsystem,operationsystem,managementsystem,gamesystem.Itgiveusalotofhelps,Itisshapeless.Substitutionforbrainthinking,thisistheessentialfeatureofsoftwareproductdifferentfromallotherengineeringproducts(4)Thequalityforengineeringistoohigh,Reachingexclusive（排它的）。Forsystemsoftware,ifonesystemhasveryhigh

qualityordevelopedfirstly,theothersoftwarewithsamefunctionhasnotanymeaning.Soitsinvestmentandspiritlostcompletely.ForexampleWindowsofmicrosoftandRedFlagofChineseScienceAcademy.However,inthebuildingengineeringisnotthecase.Twodevelopersbuildtwomansions,oneisbetter,otherisworse.Thetwopossesssamefunction,excepttheirquality,thesecondcanbeusedalso,

maybeitspriceislow.Fromthispoint,thequalityofsoftwareiscritical,cruel.Thetimeconstraintsareverystrict.Softwareengineerismoredifficult.(5)Applicationsystemhassevereinterferescomingfromsocialandadministration.

Forexample,Housestatisticsystem,thereisnotanydifficultiesintechnology,thedifficultiesarecomingfromadministrativeofficeorsomeprivilegesofsomepeople.

Twoexample:Jilin'sCornFuthreTradesytem,1992Developer:JiangYunfei,DongWenquan200seatsintradehall.Everyseatshasacomputer,

Localnetworks.Highspeedmainframecomputer.Theprojectisverysuccess.However,NationarrangedTheFutherTradeCenterattheZhengZhoucityofHenanprovence,ourprojectisstopped.

GuangDongProvince'sFireBrigadeOfficeSystem1998developedbyTheinstituteofComputerSoftwareofSYSUaboutlogisticsmoduleInthepersonnelmoduletherearealistofofficersandsoldiers,bythestandardofNationalArmy,everyofficerorsoldierhasdefiniteamounttosupply,sothisissimplecalculation.However,theleadersofthelogisticsdepartmentdonotagreethesimplecalculation.(6)Theproductofsoftwareismalleable.Allotherproductsofengineeringhavetimeboundahouse:70yearsabridge:100years,itsusagevalueislessenedastimeisflowing.Theproductofsoftwaremaybeverylong.Itcanbeimprovedconstantly.Itspowermaybestrongerandstronger.forexample,asystemwithlearningability.wemustconsiderthefeatureofproductofsoftware.automatedamassment

Thespecialityofsoftwareengineeringismorethanthecommonalityforothergeneralengineering.Whetherthecommonmanagementrules,principles,standardscanbeusedtosoftwareengineering?Thecommontrend:Usinganunifyingprinciplestoguidesoftwareengineering.Insum,thereareafewsimilaritiesbetweenbridgesandsoftwaresystems,buttherearemanysalientdifferences.Sowhythisgeneralexhortationtotrytobuildand

designprogramsinthemouldsuccessfullyusedforbridges?Isitamisguidedcampaignfuelledbylittlemorethandesperation?Whatthesoftwarepeoplereallyhopetoimportintotheirdisciplineisproductreliability?Butarebridges,buildings,andsteamenginesreliablebecausethetechnologyiswellunderstood,inthesenseofwelldefined,orbecausetheartefactsareproducedasaresultofrigidadherencetoacompleteandprecisespecificationofdesiredbehavior.Couldthesoftwareengineeringtodosimilarly?Theanswerisnotclearly.Book:“Artificialintelligenceandsoftwareengineering”TheremaybeleadtosomemistakesNeglecttherequirements.Neglectthenecessarydeclaration.Neglectthetestandmaintenance.Learningsoftwareengineeringandtodoaqualifiedsoftwareengineer:youmusthaveyourownthinking.youcannotconfineyourselfinCodesandRulesofbooks.youcannotlearnthecourseinthestudioorinivorytower.Youshouldlearnthecoursebypractice.youshouldbeshrewd3.advancedInnovation,thenewideas,thenewtechnology,thenewmethods,thenewdevelopingprocessthenewtoolsforsoftwaredeveloping,thenewtestmethod,maintainmethods.

Forexample,softwareandAI,UseAItechniquetosoftwareengineering,InJilinBuildingBudgetSystem-85,useAIrotelearningtechnique,solvethebuildingstandardsStoreproblem.PresentAssembleDevelopingmethodsUsemodel-baseddiagnosestosoftwaresystem.Thenewtechnology:Thenewdevelopmentofcomputerpresentsnewproblem,promotethenewtechniquesinsoftwaredevelopingForexample,internetanddatabasepromotethedevelopingBasedmiddleware.Practiceistheonlystandardtotesttheideas.5.ThepurposeofthecourseGrasptheadvancedknowledgeandtechnology,preparetoattendindevelopingsoftwaresystem.Doresearchworkinthesoftwarearea.Presentnewideasnewview,newtechnology.Getthetraininginthedevelopingsoftwaresystem.6.Howtolearnthecourse?Takelesson,think,discuss.Readbook,papers.Takepartindeveloping."TheSunZi'sArtofWar"孙子兵法

全世界的军事院校几乎都学孙子兵法，学过孙子兵法的军人有几十万，可是世界著名的常胜将军却寥寥数人。Sopracticeisveryimportant.Youshouldcombinethetheoryinthebookandthespecificcasethatyouface.7.PrecedentcoursesDiscretemathematicsDatastructureSoftwareengineeringjava8.Reference1.SoftwareengineeringtheoryandpracticeShariLawrencePfleeger,JoanneM.Atlee2.FrontiersinArtificialIntelligenceandApplications:NewTrendsinSoftwareMethodologies,ToolsandTechniquesFujita,H.Gavrilova,T.9.Scoreandevaluation1.QandA,Discussion,Test,20%2.ReadpaperandNote,20%3.Takingparttraining,20%4.Termexamination,40%Thechallengeraisedbynetenvironment

communicationproblemofsoftwaresdifferenttypesofresourceslocationproblemofresoucesinnetSoundnessofwholesystemsecurityproblemmaintainanceproblrminternetagentChapter0习题什么是软件工程?与其他工程的产品比较,软件工程产品有什么特点?软件开发的步骤有哪些?ThankYouTheendofChapter0

Chapter1SoftwareandSoftwareDeveloping

1.1Software1.2ThePresentSituationofSoftwareDeveloping

1.3ThefeaturesforSoftwareDeveloping1.4InfluencesbroughtbyNet1.5Wasserman’sDisciplineofSoftwareEngineering

1.1Software1、Whatissoftware?2、ThePresentSituationofSoftwareDeveloping3、ThefeaturesofSoftwareDeveloping4、TheEssentialFeatureofSoftware

1、Whatissoftware?Software=Program+DocumentProgram:TheSoftwareSystemsdescribedincomputerlanguage,Canrunonthecomputerandgiveresult.Document:Theauxiliarydeclarationforsoftwaredescribedinnatural

language.Softwareisthecrystalofhumanknowledgeandexperiences,representedaccurately,isaproductmadebybrainofknowledge.Thecarrierofsoftware:paper,disk,tape,U-plateOfcourse,thecarrierisnotimportant,thecontentstoredincarriers,knowledgeisimportant.Softwareistheknowledge,whichcanrundirectly.Theformulainwhichwecansolvetheunitaryquadraticequation

isknowledge,touseitthestudentmustfirstlearn,howeverifwewriteitinprogram,wecansolveequationusetheequationdirectly.Softwareismysteriousartifact!Thefeaturesofsoftwareasknowledgeproductsadvantage：Itisstrictandaccurate.Itscosttocopyislow.Itiscanbeimprovedconstantly Itiseasytopropagate,inheritItsapplicationsisverywide.NearlyallfieldsofnationaleconomySoftwarebringhugechangetoourlife,study,societyandindustry,Statedefence.

ThefeaturesofsoftwareasknowledgeproductDisadvantages:Essentially,thesoftwareiscomprisedofbinarycodes,

andbuiltlevelbylevel,soitisverycomplicatedItisnoteasytounderstand.Itiseasytomakewrong.Itishardtofindthefaultsinit,anditisalsohardtorevisefaultsinit. Innetenvironment,itssoundnessandsecurityisalargeproblem.

1.2

ThePresentSituationofSoftwareDevelopingNowtherearealotofsoftware,whichruninthefieldssuchasfinancial,Communication,aeronauticsandspaceaviation(2)Theapplicationfieldsofsoftwarearewidenedconstantly,extendedto

thecommerce,trafficsandelectricalproductsforhome.(3)Thesizeandcomplexityofsoftwareisincreasingconstantly.(4)Therequirementsforsoftwarestandardsappear(5)Crossandcombinationwithothercomputerfieldsisgoingon.(6)Theautomationandintelligentitionofsoftware

TheRoleofArtificialIntelligenceinSoftwareEngineeringMarkHarmanCRESTCentre,UniversityCollegeLondon,MaletPlace,London,WC1E6BT,UK.Abstract—TherehasbeenarecentsurgeininterestintheapplicationofArtificialIntelligence(AI)techniquestoSoftwareEngineering(SE)problems.TheworkistypifiedbyrecentadvancesinSearchBasedSoftwareEngineering,butalsobylongestablishedworkinProbabilisticreasoningandmachinelearningforSoftwareEngineering.Thispaperexploressomeoftherelationshipsbetweenthesestrandsofcloselyrelatedwork,arguingthattheyhavemuchincommonandsetsoutsomefuturechallengesintheareaofAIforSE.TheessentialfeatureofsoftwareSubstitutionfeatureforthemindofbrain

对脑力思维的替代性SoftwarecansubstitutethebrainmindofhumanbeingsBeforetheappearanceofcomputer,allmechanical,electricalandelectronicproductscanonlysubstitutethephysicallaborsofmankind

Softwareisacrystalofknowledge,wemustrecognizethispoint,andpayattentiontothat,absorbtheexperiencesofspecialistsindifferentfields.Forexample,InthedevelopingofJilinBuildingbudget-85.

(2)Constructionalfeature构造性 Nootherengineeringfieldshasstrongerconstructionalfeaturethansoftwarefield,especiallyrecentyear,inordertodevelopanewsoftware,you mustspendalotoftimetosearchforagoodschemes,tools,objectstoIntegrateasystem,(3)Evolutionalfeature演化性，Theproductsinotherfields,arearestableinsizestructure,performance,etc.anditsperformanceisworsealongwiththetime,tillitcannotused.

Butthesoftwarecanbeimprovedconstantly.ForexampleWindowsandWords。Andbetterandbetter.Mechanicalandelectronicalproductsdonotpossessthefeature.(4)Rapidnessfeatureofpropagationofsoftware

软件传播的迅速性。Ifasoftwaredevelopingissuccess,youneednottodevelopinganothersamesoftware.Thesoftwarecanpropagaterapidly.

1.3ThefeaturesforSoftwareDeveloping

（1）Thescopeofapplicationofsoftwareisincreasingcontinually,softwareisgoingtobecomethebasisofthemodernsociety.

（2）Theremainingsoftwarewillcontinuetoplayitsrole.needtofurthertoimprove

（3）Thesoundnessandsecurityofsoftwareisbecomingmoreimportant.软件的可靠性与安全性日趋重要

(4)Thesoftwareinthenetenvironmentiscriticalfordeveloping.

ThequalityofsoftwareHowtoevaluateasoftwareCorrectness(2)Reliability(3)Efficiency(4)Integrity(5)Usability(6)Maintainability(7)Testability(8)Flexibility(9)Portability(10)Reusability(11)Interoperability1.4InfluencesbroughtbyNet(1)Thenetterminals(computers,movablephones)entereverycornersoftheworld.Presentnewrequirementsforsoftware.electricalcommerce,sendordersonnet.numeralhome.Officeonnet,etc(2)Theperson,whoworkinthefieldofcomputer,mustdealwithhissoftwareprojectfromsinglecomputertonetenvironment.Thesoftwareismuchmorecomplicated.(3)Thereoccursomeimportantcriticalproblems,suchassoundnessandsecurity.1.5Wasserman’sDisciplineofSoftwareEngineeringThefieldsofSE.(1)AbstractionAnabstractionisadescriptionofaproblematsomelevelofgeneralizationthatallowsustoconcentrateonthekeyaspectoftheproblemwithoutgettingmiredinthedetails.(2)AnalysisandDesignMethodsandNotationsToobtainawholedesign,thedesignersmustcommunicatetheirideaeachotherandusers.Thenotationsarethelanguagesinwhichtheydocommunication,forexample,blueprintforbuilding,flowchartforcomputer.Analysisanddesignofferusmorethanacommunicationmedium,Theyallowustobuildmodelsandcheckthem.(3)UserInterfacePrototypingUserInterfaceisthemosteffectiveanddirectmodetointeracttousersBuildingasmallversionofasystemforusers,demonstratefeasibilityandpartialfunctions.helptheuseridentifythekeyrequirementsacquiretheimprovementideasfromusers.(4)SoftwareArchitectureHowtobuildasoftware.ModulardecompositionData-orienteddecompositionEvent-orienteddecompositionOutside-indesignObject-orienteddesign(5)SoftwareprocessTheprocessofdevelopingsoftwareDifferenttypesofsoftwareneeddifferentprocessesForsmallormedium-sizedsystem,wecanuserapidapplicationdevelopment.Usetoolsandsmalldatabase.Forlargecomplexsystem,weshouldusecontrolleddevelopment.Needmorestructure,checkandbalance.(6)Reusereusingitemsfrompreviousdevelopment.Reuseisanexclusivecharacterforsoftwaredeveloping,Itcanraisethequalityandefficiencystrikingly.However,weshouldbediscreettoreuse.Theproblemsneededtoconsiderwhenreusingacomponentofsoftware

Isitfastertobuildasmallcomponentthantosearchforoneinarepositoryofreusablecomponents?Howtoguaranteethecorrectnessandsafety?forreusablecomponents?Howtowritedocuments?Howtotestareusablecomponents?Howtoestimatethehighcostofmaintenance?itisimpossibletoreadcodetosearchforalocationoffaults.theadvantagesofreuseareevident,thetroublesbroughtbyreusearealsoexplicit.(7)MeasurementMeasurementplayveryimportantroleinengineering.Itgivesanobjectivequantitivemeasuresandevaluationaboutsize,rateofadvance,materials,costaboutaproject.Makeaprojectunderpreciseplancontrol.Howeveritisdifficulttomeasureasoftware.Itisaproductofmentalaction.Itisdifficulttomeasureinquantity.Itissimilartoevaluateateachersbynumberofpapers(8)ToolsandIntegratedEnvironmentsToolscanraisetheefficiencyandquantityinengineering.Thetoolsinsoftwareengineeringincludeplatforms,designtools,testtools.

Chapter1.问题

谈谈目前软件开发所面临的形势.在软件开发中应注意哪些问题?网络对软件开发有哪些影响?评价软件产品的质量应从哪些方面考虑？

ThankYouTheendofChapter1

Chapter2PlanningofSoftwareEngineering

2.1Thestepsforsoftwaredeveloping2.2Asoftwareapplicationsystem2.3TheTrendofSoftware2.4Somechangesinsoftwaredevelopingneededtopayattention

2.1ThestepsforSoftwareDeveloping1、CapturingtheRequirements2、Designingthesystem3、Consideringtheobjects4、writingtheprograms5、Testingtheprograms6、Testingthesystem7、Deliveringthesystem8、maintainingthesystem9、Otherproblemsneededtoconsider2.1ThestepsforSoftwareDeveloping1、CapturingtheRequirementsWhatisofrequirementacquirementTheimportanceofrequirementacquirementTheadvicesofrequirementacquirementTheverificationofrequirementacquirementTheprocessofsystemrequirementProblemanalysisProblemdescriptionPrototypeAndcheckdocumentverificationelicitationRequirementspecificationTheprocessofcapturingrequirementisveryimportant.Thehardsinglepartofbuildingasoftwaresystemisdecidingwhattobuild,Nootherpartsoftheconceptualworkisasdifficultasestablishingthedetailedtechnicalrequirements,includingalltheinterfacetopeople,tomachinesandtoothersoftwaresystems.Nootherpartsoftheworksocripplestheresultingsystemifdonewrong.Nootherpartismoredifficulttorectifylater.Brooks1987RodneyAllenBrooks(bornDecember30,1954)isanAustralianroboticist,FellowoftheAustralianAcademyofScience,author,androboticsentrepreneur,mostknownforpopularizingtheactionistapproachtorobotics.HewasaPanasonicProfessorofRoboticsattheMassachusettsInstituteofTechnologyandformerdirectoroftheMITComputerScienceandArtificialIntelligenceLaboratory.HeisafounderandformerChiefTechnicalOfficerofiRobot[1]andco-Founder,ChairmanandChiefTechnicalOfficerofRethinkRobotics(formerlyHeartlandRobotics).OutsidethescientificcommunityBrooksisalsoknownforhisappearanceinafilmfeaturinghimandhiswork,Fast,Cheap&OutofControl软件系统是计算机界的艺术品,软件系统是知识的表达方式,是知识的结晶.软件系统是知识产品.要想做好一个软件系统,软件工程师首先要学习,然后需要创造,要像画家创作一幅优秀的绘画作品,作曲家创作大众喜欢的歌曲那样醉心自己的软件作品的制作.

姜云飞

关于《建筑预算系统85》的工作总结

Whyistheprocessofcapturingrequirementdifficult.Theaimoftheprocessistogiveagoalofsoftwaresystem,whichtheuseroftenisnotclear.inbridgebuildingandhousebuildingthegoalisgenerallydefiniteandexplicit.2.Thegapbetweensoftwareengineersandusersofotherfields，especiallytheknowledgetheypossessareradicaldifference.3.Therearesomeimportantreforms,whichareaccompaniedbyusingsoftwaresystemforapplicationfield,suchasworkflow,formatofdata.Tasksanddutiesofpeople.4.Therearesomeinfluencecomingfromsocietyandgovernmentoffice.Analyzingrequirementsinvolvesmuchmorethanmerelywritingdownthecustomerwants.WeneedtodiscusswiththecustomersrepeatedlyBeforethediscussionyoushouldcontemplatetheproject,havingyourselfidea.Youneedtoheartheother’ssuggestions.especiallythecriticalopinionsTheusefuladviceoftenmakesyoudiscomfortable,

butItbenefitstoyou.Theeulogy,assoundingamelodioussongonlygiveyourheartpleasant.CannotgiveyoupracticalguidesThesesayingsarecommon,beyondtheSE.ContentsofrequirementacquisitionRequirementelicitationRequirementspecificationRequirementverificationRequirementrevisionRequirementdocumentRequirementsignatureRequirementisablueprintofsoftwaresystemHowtodorequirementacquisition?ThereisnoCodeasHouseBuildingDomainshave.ThereareonlysomesuggestionsgivenbyrelevantbooksTherearelessconfined,sothereareimaginationandcreativespace.

Myexperience,andadvices1.Payhighattentionrequirementacquisition.2.Donothurry,qualityisfarmoreimportantthanspeed.Ifyourushtodothesoftwarerequirement,andpushthelaterstepsofthedevelopment,beforelongyouwillfoundyoufallintoamireyoumusttoreturnthestartpointandbeginagain.Notonlythisdoingagainwastealargeamountofmoneyandtime,butalsoitgiveblowtoyou,makesyoudiscourage.3.Musthaveusersattend4.Mustlearnfromusers,communicateandcooperatewiththem.Youshouldbeaqualifiedprofessionalinthespecificdomain.youshouldbereallymodestandhumble,notinsurface.5.Satisfytheuser’srationalrequirementasmuch