软件工程教学大纲.docx

软件工程教学大纲.docx

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软件工程教学大纲

Chapter1AnIntroductiontoSoftwareEngineering

1.WhatisSoftware?

Softwareisbothalogicalandaphysicalsystemelement.Softwareisasetofitemsorobjectsthatforma“configuration”thatincludesprograms,documents,dataandotherrelateditems。

2.SoftwareCharacteristics：

⏹Softwareisdevelopedorengineered,itisnotmanufactured。

⏹Softwaredevelopmentpresentsajob-shopenvironment。

⏹Timeandeffortforsoftwaredevelopmentarehardtoestimate.

⏹Userrequirementsareoftennotconceivedwellenough;thereforeapieceofsoftwareundergoesmanymodificationsbeforeitisimplementedsatisfactorily.

⏹Therearevirtuallynoobjectivestandardsormeasuresbywhichtoevaluatetheprogressofsoftwaredevelopment.

⏹Testingasoftwareisextremelydifficult,becauseevenamodest-sizedprogram（<5,000executablestatements）cancontainenoughexecutablepaths（i.e.,waystogetfromthebeginningoftheprogramtotheend）,sothattheprocessoftestingeachpaththoughtheprogramcanbeprohibitivelyexpensive

3.4bigchallengesfacingsoftwareengineering

⏹Time:

Whydoesittakesolongtogetsoftwarefinished?

⏹Measurement:

Whydowehavedifficultyinmeasuringprogressassoftwareisbeingdeveloped?

⏹Cost:

Whyaredevelopmentcostssohigh?

⏹Errors/Quality:

Whycan’twefindalltheerrorsbeforewegivethesoftwaretocustomers?

4.Softwarecrisis

“Softwarecrisiswasatermusedintheearlydaysofcomputingscience.Thetermwasusedtodescribetheimpactofrapidincreasesincomputerpowerandthecomplexityoftheproblemswhichcouldbetackled.Inessence,itreferstothedifficultyofwritingcorrect,understandable,andverifiablecomputerprograms.Therootsofthesoftwarecrisisarecomplexity,expectations,andchange.

5.Whatissoftwareengineering?

6.SevenPrinciplesforSoftwareEngineering

⏹Manageusingaphasedlife-cycleplan

⏹Performcontinuousvalidation

⏹Maintaindisciplinedproductcontrol

⏹Usemodernprogramming/engineeringpractices

⏹Maintainclearaccountabilityforresults

⏹Usebetterandfewerpeople

⏹Maintainacommitmenttoimprovetheprocess

Chapter2ProcessModels

1.TheCMMI—5levels

⏹Initial:

Thesoftwareprocessischaotic.Fewprocessesaredefined,andsuccessdependsonindividualeffort.

⏹Repeatable:

thenecessaryprocessdisciplineisinplacetorepeatearliersuccessesonprojectswithsimilarapplications.

⏹Defined.Thesoftwareprocessforbothmanagementandengineeringactivitiesisdocumented,standardized,andintegratedintoanorganizationwidesoftwareprocess.

⏹Managed.Detailedmeasuresofthesoftwareprocessandproductqualityarecollected.

⏹Optimizing.Continuousprocessimprovementisenabledbyquantitativefeedbackfromtheprocessandfromtestinginnovativeideasandtechnologies

2.WaterfallModel

⏹Strength：

1）.theoldestandmostwidelyused;

2）.betterthanrandom.

⏹Weaknesses:

1）.Notfollowsequentialflow

2）.Difficultytostateallrequirements

3）.Customerswaiting/patience

3.EvolutionaryModel

⏹CombineselementsofLSM（appliedrepetitively）withtheiterativephilosophyofprototyping

⏹--prototyping

⏹--concurrentdevelopmentmodel

4.Components-basedModel

⏹Requirements:

It’ssameasothermodels.

⏹Componentsanalysis:

Giventherequirementsspecification,asearchismadeforcomponentstoimplementthatspecification.

⏹Systemdesign:

Thisdesignhassomedifferenceswithothermodels,becausethisdesignisbasedonreuse.

⏹Developmentandintegration:

Inthisstage,thecomponentsshouldbeintegratedintoacompletesystem.

5.IncrementalProcessModels

⏹Theincrementalmodelcombinesthebasicelementsandtheiterationcharacteristicoftheprototypingmodel,itadoptsthelinersequencesalongthetime,eachlinersequenceproduces“increments”ofthesoftware.

⏹--Incrementalmodel

⏹--RADmodel

⏹--Spiralmodel

6.Howtochooseprocessmodels

⏹Itdepends.Differentprocessmodelshavedifferentstrengthsandweaknesses,basedontherequirementsofaproject,suitableprocessmodelcanbechose.

⏹Sometimes,acombinationofdifferentmodelsmaybeagoodoption

Chapter3SystemEngineeringandRequirementEngineering

1.DefiningObjectivesandGoals

⏹Objective—generalstatementofdirection

⏹Goal—definesmeasurableobjective:

“reducemanufacturedcostofourproduct”

⏹Subgoals:

⏹decreaserejectrateby20%infirst6months

⏹gain10%priceconcessionsfromsuppliers

⏹re-engineer30%ofcomponentsforeaseofmanufactureduringfirstyear

⏹Objectivestendtobestrategicwhilegoalstendtobetactical（achievable）

2.SoftwareRequirementsFundamentals

⏹DefinitionofaSoftwareRequirement

⏹ProductandProcessRequirements

⏹FunctionalandNon-functional

⏹QuantifiableRequirements

⏹SystemRequirementsandSoftwareRequirements

3.FunctionalandNon-functional

⏹Functionalrequirementsdescribethefunctionsthatthesoftwareistoexecute;e.g.,formattingsometextormodulatingasignal.Theyaresometimesknownascapabilities.

⏹Non-functionalrequirementsaretheonesthatacttoconstrainthesolution.Non-functionalrequirementsaresometimesknownasconstraintsorqualityrequirements

4.SystemRequirementsandSoftwareRequirements

⏹systemmeans‘aninteractingcombinationofelementstoaccomplishadefinedobjective.Theseincludehardware,software,firmware,people,information,techniques,facilities,services,andothersupportelements,’asdefinedbytheInternationalCouncilonSystemsEngineering.

⏹Systemrequirementsaretherequirementsforthesystemasawhole.

⏹Inasystemcontainingsoftwarecomponents,softwarerequirementsarederivedfromsystemrequirements.

5.RequirementsAnalysis

theprocessofanalyzingrequirementsto:

⏹detectandresolveconflictsbetweenrequirements

⏹discovertheboundsofthesoftwareandhowitmustinteractwithitsenvironment

⏹elaboratesystemrequirementstoderivesoftwarerequirements

6.ConceptualModeling

7.ArchitecturalDesignandRequirementsAllocation

Chapter4DesignEngineering

1.3CharacteristicsofaGoodDesign

⏹[MCG91]Thedesignmustimplementsall（explicitandimplicit）requirements

⏹Thedesignmustbereadable,understandableguideforpractitioners

⏹Shouldprovideacompletepicture（biganddetailed）

⏹“Writingacleverpieceofcodethatworksisonething;designingsomethingthatcansupportalong-lastingbusinessisquiteanother.”–C.Ferguson

2.EvolutionaryofSWDesign

3.8DesignGuidelines

⏹exhibitanarchitectureofthewholesystem

⏹bemodular（canbepartitionedintosubsystems）

⏹containdistinctrepresentationofdata,architecture,interfaces,andcomponents

⏹Leadtodatastructures

⏹leadtocomponents;

⏹leadtointerfaces

⏹bederivedusingarepeatablemethod

⏹berepresentedusinganeasycommunicationnotation

4.7DesignPrinciples

⏹Betraceabletotherequirementanalysismodel,avoidconceptual（semantic）errors

⏹Notreinventthewheelbutusingexistingpatterns

⏹Mimicthestructureofproblemdomain

⏹Today:

SoftwareArchitectureanddesignpatterns

⏹Exhibituniformityandintegration

⏹Structuredtoaccommodatechanges

⏹Designisnotcodingorviceversa（Today）

5.InformationHiding

⏹Information（procedureanddata）containedwithinamoduleisinaccessibletoothermodulesthathavenosuchinformation

⏹Abstraction:

definestheprocedural（informational）entitiesthatmakeuptheSW.

⏹Hiding:

enforcesconstraintstobothexternal（procedural）andlocaldatastructure

⏹GreatBenefit:

whenmodificationduringtestingandmaintenance,constrainterrorpropagatetootherlocations

6.SoftwareArchitecture

⏹Learntfromarchitectureofbuildings

⏹Itincludes:

overallshapeofphysicalstructure;

⏹fittingintoenvironments;feelingofart…

⏹Definition:

isthestructureofthesystem,whichcomprisessoftwarecomponents,theexternallyvisiblepropertiesofthosecomponents,andtherelationshipsamongthem

⏹Isnottheoperationalsoftware

⏹ButastructuralrepresentationenablesSEtodo

⏹

（1）analyzetheeffectivenessofthedesigninmeetingrequirements

⏹

（2）considerarchitecturalalternativesatastagewhenmakingdesignchangesrelativelyeasy

⏹（3）reducingtherisksassociatedwiththeconstructionofthesoftware

7.DataDesign（architecture）

⏹Datamodeling

⏹Datastructures

⏹Databases

⏹DataWarehouse:

independentdatabaseencompassessome（notall）ofthedataindatabasesthatservethesetofapplications

⏹eg.Biology,Internet-scale

⏹Dataminingorknowledgediscoveryindatabase（KDD）

⏹Datadesignatthecomponentlevel

8.EvaluationofArchitecturein6steps

⏹Howdoyouknowwhicharchitectureisgoodforyourproject?

⏹SoftwareEngineeringInstitute（SEI）:

Architecturetrade-offanalysismethod（ATAMorATM）,aniterativeprocess

⏹1）.Collectscenarios;2）.Elicitrequirements,constraints;3）.Describethearchitecturalstyles/patternsbasedon1）and2）;4）.Evaluatequalityattributes[reliability,performance,security,maintainability,flexibility,testabilityetc]separately5）sensitivityevaluation:

asmallchangetothesystemtoseehowotherqualityattributeswillbeaffected.Sensitivitypointsforsignificantlyaffectedattribute

Chap5SoftwareProductivityandEffortMetrics

1.DefinitionofSoftwareProductmetrics

⏹Softwareproductmetricsarequantitativemeasuresthatenablepeopletogaininsightintotheefficacyofthesoftwareprojects.

⏹TheIEEEStandardGlossaryofSoftwareEngineeringTerms[IEE93]definesmetricas“aquantitativemeasureofthedegreetowhichasystem,component,orprocesspossessesagivenattribute.”

2.Size-basedMetrics

3.Function-Base