Change Management in Families of Safety-Critical E

ChangeManagementinFamiliesofSafety-CriticalEmbeddedSystemsZo¨eRachaelStephensonThisthesisissubmittedinpartialfulfilmentoftherequirementsforthedegreeofDoctorofPhilosophy.UniversityofYorkYorkYO105DDUKDepartmentofComputerScienceMarch2002AbstractThisthesisaddressestheproblemofunderstandingchangeandreducingtheworkneededtoestimateandrespondtochangeinfamiliesofsafety-criticalembeddedsystems.Explicitfam-ilyfeaturemodellingtechniquesaredevelopedthatrecordthecontextwithinwhichafeatureisvalidforeachfamilymember.Thesefeaturesarecombinedwithadescriptionoftheirallowedvariationamongdifferentmembers,toprovideacompletefamilyfeaturemodel.Thesetech-niquesareusedtocreateafamilyfeaturemodelforanumberofindustrialprojects.Compar-isonsaremadebetweentheabilityofthefamilymodelandtheprojectprocessestoaccuratelyestimatechangeimpact.Resultsshowthatthefamilymodelprovidesmoreaccuratechangeimpactestimationthantheexistingprojectprocesses.Italsoprovidesanunderstandingoftheroleofdomainknowledgeinimpactestimation,amethodbywhichdifferenttypesofspeci-ficationmaybetracedtooneanotherthroughoutthedevelopmentprocess,andaprocessbywhichindividualfeaturedescriptionsaretransformedintosinglefamilydescriptions.2ContentsAbstract2Acknowledgement12Declaration131Introduction151.1EmbeddedSystems................................151.2OperatingConstraints...............................191.3Safety-relatedSoftware..............................201.4Families......................................211.5ChangeCharacteristics..............................221.6Hypothesis....................................232LiteratureReview252.1DesignProcess..................................252.1.1DevelopmentLifecycleModels.....................252.1.2Automation................................322.1.3Traceability................................342.1.4RationaleDescription...........................352.2FamiliesandDomains..............................472.3ChangeImpact..................................522.3.1SoftwareChangeImpact.........................542.3.2Non-softwareChange..........................562.4Summary.....................................583FeatureRepresentation593CONTENTSCONTENTS3.1AnalysisModel..................................603.1.1KeyConcepts...............................613.1.2Objectivesgraphs.............................633.1.3IBIS....................................633.1.4REMAP..................................653.1.5OSCS...................................663.1.6Redux...................................673.1.7DRCS...................................683.1.8Summary.................................703.2RepresentationAssessment............................703.2.1Goals...................................703.2.2Decisions.................................743.2.3Results..................................753.2.4ContextandAssumptions........................773.2.5Summary.................................803.3RepresentationSynthesis.............................813.3.1Goal....................................833.3.2Decision.................................833.3.3Solution..................................843.3.4Property..................................843.3.5Assertions.................................853.4DecisionTraces..................................853.4.1Notation.................................853.4.2TraceSheets...............................903.4.3AnalysisandArgumentation.......................933.5Summary.....................................954FamilyRepresentation974.1Introduction....................................974.2Review......................................984.2.1DesignRationaleApproaches......................984.2.2Product-lineApproaches.........................1024CONTENTSCONTENTS4.3ModelDevelopment...............................1034.3.1FeatureAssociation............................1054.3.2ChoiceandChoiceConstraints......................1064.3.3FeatureDependencies..........................1104.4TraceSheets....................................1154.5Summary.....................................1175FamilyFeatureModel1215.1Analysis......................................1215.1.1Scoping..................................1215.1.2Sources..................................1215.1.3AnalysisResults.............................1225.2Modelling.....................................1245.3IndustrialProjectData..............................1255.4Summary.....................................1276FeatureOrderingandResolution1286.1Introduction....................................1286.2Resolution.....................................1296.3Representation..................................1316.4Motivation.....................................1356.4.1SingleModelRationale.........................1356.4.2ProcessRationale.............................1366.5SpecificResolutionGuidelines..........................1376.5.1Correspondence..............................1376.5.2Elaborate.................................1406.5.3Constraint.................................1436.5.4Option..................................1436.5.5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