Formal Methods of Argumentation as Models of Engineering Design Decisions and Processes

253 Pages·2016·1.46 MB·English

by  Jann Müller

Formal Methods of Argumentation as
Models of Engineering Design
Decisions and Processes
Jann Mu¨ller
Adissertationsubmittedinpartialfulfillment
oftherequirementsforthedegreeof
DoctorofPhilosophy
of
UniversityCollegeLondon.
DepartmentofComputerScience
UniversityCollegeLondon
December4,2016
2
I, Jann Mu¨ller, confirm that the work presented in this thesis is my own. Where
informationhasbeenderivedfromothersources,Iconfirmthatthishasbeenindicated
inthework.
Abstract
Complex engineering projects comprise many individual design decisions. As these
decisionsaremadeoverthecourseofmonths,evenyears,andacrossdifferentteamsof
engineers,itiscommonforthemtobebasedondifferent,possiblyconflictingassump-
tions. The longer these inconsistencies go undetected, the costlier they are to resolve.
Therefore it is important to spot them as early as possible. There is currently no soft-
wareaimedexplicitlyatdetectinginconsistenciesininterrelateddesigndecisions.
This thesis is a step towards the development of such tools. We use formal meth-
ods of argumentation, a branch of artificial intelligence, as the foundation of a logical
model of design decisions capable of handling inconsistency. It has three parts. First,
argumentationisusedtomodeltheprosandconsofindividualdecisionsandtoreason
aboutthepossibleworldsinwhichtheseargumentsarejustified. Inthesecondpartwe
study sequences of interrelated decisions. We identify cases where the arguments in
one decision invalidate the justification for another decision, and develop a measure of
the impact that choosing a specific option has on the consistency of the overall design.
Thefinalpartofthethesisisconcernedwithnon-deductivearguments,whichareused
in design debates, for example to draw analogies between past and current problems.
Ourmodelintegratesdeductiveandnon-deductiveargumentsside-by-side.
This work is supported by our collaboration with the engineering department of
Queen’s University Belfast and an industrial partner. The thesis contains two case
studies of realistic problems and parts of it were implemented as software prototypes.
Wealsogivetheoreticalresultsdemonstratingtheinternalconsistencyofourmodel.
Acknowledgements
Thereareanumberofpeoplewho,invariousways,arejustasresponsibleforthesuc-
cessful completion of this project as I am. I would like to extend my sincere gratitude
toeveryonewhohassupportedmyworkonthisprojectoverthelastfewyears.
First I would like to thank Prof. Anthony Hunter who supervised my thesis at
UCL. Besides being the most knowledgeable mentor he has always shown enthusiasm
andwillingnesstodiscussnewideas,aswellasagreatdealofpatience. Hewasalways
willing to dedicate time to this project, both in personal meetings and when reviewing
thelatestdrafts. Idonotthinktherecouldbeabettersupervisor.
Then I would like to thank my wife Mary-Anne, who thought I would submit “a
coupleofmonths”afterwefirstmet. Shetoohasbeenverypatientwiththisthesis,and
her encouragement (and help with the children) greatly contributed to its successful
completion.
I want to thank my former coworkers at SAP: Phil, Alan, Fergal, Mary, and our
friendsfromEastGermany,forcreatingastimulatingenvironmentformyresearch,and
for being good colleagues all around. Further I want to thank David Payne at QUB for
sharing the results of his experiments, and Fiona Browne for good advice throughout
the project. With my old friend Christian Hoffmann I had many conversations that
helpedshapedbothourviewsonuncertaintyandIthankhimforthat. Iamalsograteful
to my second supervisor Prof. John Dowell for his insights on engineering design, and
toTobiasTrappforworkingwithmeonaninterestingapplicationofthetheory.
Finally I want to thank Pat and Carmel for support and proof-reading, and my
parentsforsupportingmeinmyacademicendeavours.
ThisworkissupportedbySAPAGandtheInvestNICollaborativeGrantforR&D
-RD1208002.
Contents
1 Introduction 12
1.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
1.2 DecisionProcesses . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
1.2.1 DecisionsinContext: MotivatingExamples . . . . . . . . . . . 12
1.2.2 RequirementsforaFormalModelofDecisionProcesses . . . . 14
1.2.3 DecisionModels . . . . . . . . . . . . . . . . . . . . . . . . . 16
1.2.4 FormalMethodsofArgumentation . . . . . . . . . . . . . . . . 18
1.3 ThesisOverview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
1.4 Contributions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
1.5 Publications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
1.5.1 Mainauthorship . . . . . . . . . . . . . . . . . . . . . . . . . 21
1.5.2 Co-authorship . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
2 Background 23
2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
2.2 AbstractArgumentation . . . . . . . . . . . . . . . . . . . . . . . . . . 24
2.3 Aspic+ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
2.3.1 FormalDefinitionofAspic+ . . . . . . . . . . . . . . . . . . . 28
2.3.2 ASPIC+ Conventions . . . . . . . . . . . . . . . . . . . . . . . 32
2.3.3 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
2.4 AdditionalDefinitions . . . . . . . . . . . . . . . . . . . . . . . . . . 36
2.5 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
2.5.1 GroundedandPreferredSemantics . . . . . . . . . . . . . . . 40
2.5.2 Alternativesto ASPIC+ . . . . . . . . . . . . . . . . . . . . . . 41
Contents 6
3 Argument-BasedDecisionMaking 43
3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
3.2 TwoModelsofDecisionMaking . . . . . . . . . . . . . . . . . . . . . 45
3.2.1 Multi-CriteriaDecisionMaking . . . . . . . . . . . . . . . . . 45
3.2.2 DecisionMakingunderUncertainty . . . . . . . . . . . . . . . 47
3.2.3 DocumentationofDecisions . . . . . . . . . . . . . . . . . . . 49
3.2.4 ProblemswithCurrentApproach . . . . . . . . . . . . . . . . 50
3.3 Argument-BasedDecisionFramework(ADF) . . . . . . . . . . . . . . 52
3.3.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
3.3.2 DecisionFrames . . . . . . . . . . . . . . . . . . . . . . . . . 53
3.3.3 Multi-CriteriaDecisionMaking . . . . . . . . . . . . . . . . . 57
3.3.4 DecisionMakingWithUncertainty . . . . . . . . . . . . . . . 62
3.3.5 DecisionRules . . . . . . . . . . . . . . . . . . . . . . . . . . 69
3.4 AcceptingaDecision . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
3.4.1 OntheDeactivationofRulesin ASPIC+ . . . . . . . . . . . . . 81
3.4.2 ResultsonDeactivatingRules . . . . . . . . . . . . . . . . . . 88
3.4.3 EnforcingaPointofView . . . . . . . . . . . . . . . . . . . . 94
3.4.4 AcceptingaDecision . . . . . . . . . . . . . . . . . . . . . . . 95
3.5 RelatedWork . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
3.5.1 Multi-CriteriaDecisionMaking . . . . . . . . . . . . . . . . . 98
3.5.2 DecisionMakingWithUncertainty . . . . . . . . . . . . . . . 100
3.5.3 QualitativeDecisionTheory . . . . . . . . . . . . . . . . . . . 103
3.5.4 Enforcement . . . . . . . . . . . . . . . . . . . . . . . . . . . 104
3.6 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
3.6.1 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
3.6.2 FutureWork . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
4 Argument-basedDecisionProcess 108
4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108
4.2 UseCase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
4.2.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
4.2.2 Stage1: PreliminaryDesign . . . . . . . . . . . . . . . . . . . 110
Contents 7
4.2.3 Stage2: DetailedDesign . . . . . . . . . . . . . . . . . . . . . 111
4.2.4 Stage3: PreliminaryDesignRevisited . . . . . . . . . . . . . . 112
4.2.5 Stage4: AnotherProcessRunninginParallel . . . . . . . . . . 112
4.2.6 Stage5: JoiningtheTwoProcesses . . . . . . . . . . . . . . . 113
4.2.7 ConclusionsDrawnfromUseCase . . . . . . . . . . . . . . . 113
4.3 AModelofDecisionProcesses . . . . . . . . . . . . . . . . . . . . . . 113
4.3.1 OutcomeofDecisionStage . . . . . . . . . . . . . . . . . . . 115
4.3.2 EmbeddingDecisionsResults . . . . . . . . . . . . . . . . . . 118
4.3.3 EmbedandExtract . . . . . . . . . . . . . . . . . . . . . . . . 123
4.4 ImpactAnalysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
4.4.1 ImpactAnalysisBasedonArgumentStrength . . . . . . . . . . 130
4.4.2 ImpactAnalysisBasedonKnowledgeAddedorRemoved . . . 137
4.4.3 ImpactAnalysisforDecisionSequences . . . . . . . . . . . . . 140
4.4.4 ProgressinDecisionSequences . . . . . . . . . . . . . . . . . 149
4.4.5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153
4.5 PracticalImplications . . . . . . . . . . . . . . . . . . . . . . . . . . . 154
4.5.1 DecisionOutcomesRepresentDesignDocuments . . . . . . . . 154
4.5.2 ImpactAnalysis . . . . . . . . . . . . . . . . . . . . . . . . . 155
4.5.3 VisualisingDecisionProcesses . . . . . . . . . . . . . . . . . . 155
4.6 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158
4.6.1 RelatedWork . . . . . . . . . . . . . . . . . . . . . . . . . . . 158
5 ArgumentSchemes 165
5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165
5.2 Non-DeductiveArguments . . . . . . . . . . . . . . . . . . . . . . . . 166
5.2.1 ArgumentSchemes . . . . . . . . . . . . . . . . . . . . . . . . 167
5.2.2 InterpretingExperimentalData . . . . . . . . . . . . . . . . . . 173
5.2.3 CriticalQuestions . . . . . . . . . . . . . . . . . . . . . . . . 175
5.2.4 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176
5.3 Meta-ASPIC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176
5.3.1 DefinitionofMeta-ASPIC . . . . . . . . . . . . . . . . . . . . 178
5.3.2 Object-andMeta-LevelArguments . . . . . . . . . . . . . . . 188
Contents 8
5.4 CaseStudy: ChoosingaDrillingTechnique . . . . . . . . . . . . . . . 198
5.4.1 ConventionalorOrbitalDrilling? . . . . . . . . . . . . . . . . 199
5.4.2 ExperimentResults . . . . . . . . . . . . . . . . . . . . . . . . 199
5.4.3 InterpretingExperimentalDataUsingMeta-ASPIC . . . . . . . 200
5.4.4 SoftwarePrototype . . . . . . . . . . . . . . . . . . . . . . . . 204
5.4.5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 217
5.5 RelatedWork . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218
5.5.1 ArgumentSchemes . . . . . . . . . . . . . . . . . . . . . . . . 218
5.5.2 Meta-Argumentation . . . . . . . . . . . . . . . . . . . . . . . 219
5.5.3 BipolarArgumentation . . . . . . . . . . . . . . . . . . . . . . 221
5.5.4 Evidence-BasedArgumentation . . . . . . . . . . . . . . . . . 222
5.6 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226
6 Discussion 228
6.1 FutureWork . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 228
6.2 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229
Appendices 232
A Functions&Symbols 232
Bibliography 234
List of Figures
2.1 GraphforExample1 . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
2.2 Extensionsemantics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
3.1 JoiningTwoStructures . . . . . . . . . . . . . . . . . . . . . . . . . . 52
3.2 ArgumentgraphforExample11. . . . . . . . . . . . . . . . . . . . . . 53
3.3 ArgumentgraphforExample13. . . . . . . . . . . . . . . . . . . . . . 57
3.4 ArgumentgraphforExample16. . . . . . . . . . . . . . . . . . . . . . 64
3.5 ArgumentgraphforExample26 . . . . . . . . . . . . . . . . . . . . . 84
3.6 ArgumentgraphsforExample28. . . . . . . . . . . . . . . . . . . . . 87
3.7 ArgumentgraphforExample29. . . . . . . . . . . . . . . . . . . . . . 87
3.8 ArgumentgraphforExample29,partII. . . . . . . . . . . . . . . . . . 88
3.9 Applicationofdeactivate(cid:48) forExample29 . . . . . . . . . . . . . . . . 89
3.10 ProofofPropage19 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
3.11 Argumentgraphforreactivation,seeExample30 . . . . . . . . . . . . 94
4.1 Conceptualrelationshipofdecisionprocessesandoutcomes . . . . . . 127
4.2 Conflictsafteradecisionwaschanged(Example37) . . . . . . . . . . 129
4.3 ImpactofchangingfromS toS(cid:48) –page143 . . . . . . . . . . . . . . . 145
4.4 DEEPFLOW: Visualisationofasetofdesigndocuments. . . . . . . . . 155
4.5 Visualisationofexampleprocess. . . . . . . . . . . . . . . . . . . . . . 157
5.1 Reifiedgraphofthemeta-ASPIC systemfromFigure5.2onpage185 . 182
5.2 Meta-ASPIC graphwithargumentschemes . . . . . . . . . . . . . . . 185
5.3 Reifiedgraphofmeta-ASPIC systemwithargumentschemes. . . . . . . 186
5.4 ArgumentgraphsforExample57 . . . . . . . . . . . . . . . . . . . . . 193
5.5 ArgumentgraphsforExample58 . . . . . . . . . . . . . . . . . . . . . 194
ListofFigures 10
5.6 RulepartsandruletypesinHaskell . . . . . . . . . . . . . . . . . . . 205
5.7 GeneratedSQLqueryforpublication(X,Y) . . . . . . . . . . . . . . 207
5.8 GeneratedSQLqueryforCOUNT(publication(X,Y)≤3) . . . . . . . 207
5.9 RelationshipofD+,DandD(cid:48) inTheorem7 . . . . . . . . . . . . . . . 217