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Based on Computational Social Choice and

Argumentation

Nikos Karanikolas, , Patrice Buche, Christos Kaklamanis, Rallou

Thomopoulos

To cite this version:

Nikos Karanikolas, , Patrice Buche, Christos Kaklamanis, Rallou Thomopoulos. A Decision Support Tool for Agricultural Applications Based on Computational Social Choice and Argumentation. In-ternational Journal of Agricultural and Environmental Information Systems, IGI Global, 2018, 9 (3), pp.54-73. �10.4018/IJAEIS.2018070104�. �lirmm-01893516�

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DOI: 10.4018/IJAEIS.2018070104



Copyright©2018,IGIGlobal.CopyingordistributinginprintorelectronicformswithoutwrittenpermissionofIGIGlobalisprohibited.

A Decision Support Tool for Agricultural

Applications Based on Computational

Social Choice and Argumentation

Nikos Karanikolas, Department of Computer Engineering and Informatics, University of Patras, Patras, Greece Pierre Bisquert, IATE, University Montpellier, INRA, CIRAD, Montpellier SupAgro, Montpellier, France & INRIA GraphIK, LIRMM, Montpellier, France

Patrice Buche, IATE, University Montpellier, INRA, CIRAD, Montpellier SupAgro, Montpellier, France & INRIA GraphIK, LIRMM, Montpellier, France

Christos Kaklamanis, Department of Computer Engineering and Informatics, University of Patras, Patras, Greece & CTI - Computer Technology Institute and Press “Diophantus”, Patras, Greece

Rallou Thomopoulos, IATE, University Montpellier, INRA, CIRAD, Montpellier SupAgro, Montpellier, France & INRIA GraphIK, LIRMM, Montpellier, France

ABSTRACT Inthecurrentarticle,theauthorsdescribeanappliedproceduretosupportcollectivedecision makingforapplicationsinagriculture.Anextended2-pageabstractofthispaperhasbeen acceptedbytheEFITAWCCAcongressandthismanuscriptisanextendedversionofthis submission.Theproblemtheauthorsarefacinginthispaperishowtoreachthebestdecision regardingissuescomingfromagriculturalengineeringwiththeaidofComputationalSocial Choice (CSC) and Argumentation Framework (AF). In the literature of decision-making, severalapproachesfromthedomainsofCSCandAFhavebeenusedautonomouslytosupport decisions.Itisourbeliefthatwiththecombinationofthesetwofieldstheauthorscanpropose sociallyfairdecisionswhichtakeintoaccountboth(1)theinvolvedagents’preferencesand (2)thejustificationsbehindthesepreferences.Therefore,thisarticleimplementsasoftware toolfordecision-makingwhichiscomposedoftwomainsystems,i.e.,thesocialchoicesystem andthedeliberationsystem.Inthisarticle,theauthorsdescribethoroughlythesocialchoice systemofourtoolandhowitcanbeappliedtodifferentalternativesonthevalorizationof materialscomingfromagriculture.Asanexample,thatisdemonstratedanapplicationofour toolinthecontextofEcobiocapEuropeanprojectwhereseveraldecisionproblemsaretobe addressed.Thesedecisionproblemsconsistinfindingthebestsolutionsforquestionsregarding foodpackagingandend-of-lifemanagement. KEywoRDS

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1. INTRoDUCTIoN Collectivedecision-makingandpreferenceaggregationarewidelyusedinmodernsocieties.The mostwell-knownexampleofcollectivedecision-makingispoliticalelectionsbutitisnottheonly onesincethereareanumberofsituationswheretheaggregationoftheindividualpreferencesis neededtotakeadecision.Considerforexamplesituationssuchasagroupoffriendschoosingwhere tohavedinneroracommitteeboardchoosingwhatisthebeststrategyforthecompany.Inallthese caseswhatweareseekingisawaytofairlyaggregatethepreferencesoftheindividualagentsinto acollectivepreferenceandthusobtainadecisionwhichsatisfiesthegroupasatotal.Thissetting canbedirectlyappliedalsointhedecision-makingforagriculturalproblems.Suchanexampleisa problemwherethedecisionlaysinevaluatingtheinterestandpotentialofmarketingnewgeneration packagingmadeofagro-wastematerials.Here,theconsumersareaskedtoexpresspreferencesamong differentpackaging. Wearestudyingtheclassicalcollectivedecision-makingproblem,wherewehaveasetof alternativeoptionsandasetofagentsandeachagentiscalledtoexpressherpreferenceoverthe alternativesbyproducingalinearorderonthem.Inmostofthesecollectivedecision-makingproblems thepreferenceaggregationisdonebyusingsimpleaggregationmethods,suchastheplurality votingrule,andthetoolsthatareusedaresimpleandnotevenintendedtoservethispurpose.For example,doodleisonesuchunsuitabletoolthatisusedforpreferenceaggregationwhileitsoriginal functionalitywasforschedulingjointactivities.Therefore,weproposeaprocedureforsupporting morecomplexcollectivedecision-makingproblems,whichcanbedirectlyappliedinthecontextof agriculturalapplications.Ourobjectiveistoexpandthisclassicalcollectivedecision-makingproblem byaskingtheagentstoconsiderthereasoningbehindthelinearorderingofthealternatives.Hence, thegoalofthisworkistobuild,i.e.,designandimplement,asoftwaretoolfordecision-making thattakesintoaccounttheoreticalinsightsfromsocialchoiceandargumentationinordertopropose socialfairdecisionsthattakeintoaccountthepreferencesoftheagentsandthereasoningbehind thesepreferences. 1.1. Related work TheapplicationofArgumentationFrameworkandSocialChoicehavingasagoalthesupportof DecisionAnalysisisarelativelynewfield;howevertherehasbeensignificantresearchtowards decision-makingonbothofthesefieldsindependently. Multi-CriteriaDecisionAnalysis(MCDA)hasfirststartedevolvinginthe60swhenBenayoun, Roy,andSussman(1966,1968)introducedtheclassofELECTREmethodsforaggregatingpreferences expressedonmultiplecriteria.TheELECTREmethodssetthefoundationsforthe“outranking” methods(Ostanello,1985;Roy,1991)whichwasthefirststepofintegratingnotionsofsocial choiceintodecision-making.MCDAandCSCaretwocloselycorrelatedfieldswhoseobjectiveis toaggregatethepartialpreferencesintoacollectivepreference.ArrowandRaynaud(1986)were thefirstthatpresentedageneralexplorationofthelinksbetweenCSCandMCDA.Votingmethods fromsocialchoicetheoryhavebeenintegratedintheanalysisofsomepopularaggregationmethods inmulti-criteriadecision-aiding.Letusmention,forexample,theCondorcetmethod,onwhichthe ordinalmethodsinmulticriteriaanalysis,e.g.,(Roy,1991;Roy&Bouyssou,1993)arebasedand theBordamethodonwhichthecardinalones,e.g.,(VonWinterfeldt&Edwards,1986;Keeney& Raiffa,1993)arebased. SeveralresearchershaveproposedtheuseofArgumentationindecision-makinganalysis.The workofFoxandParsons(1997)isoneofthefirstworksthattriedtodeployanargumentativeapproach todecision-makingstatingthedifferencebetweenargumentationforactionsandargumentationfor beliefs.Theobjectiveofmostoftheargumentation-basedapproaches(Karacapilidis&Papadias, 1998;Morge&Mancarella,2007)istoselectthebestsolution(alternativeoption)comparedto decisionanalysis,wheretheobjectivecanhaveseveraldifferentproblemstatements,i.e.,choosing,

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rejecting,ranking,classifyingthesetofalternatives.Regardingtheaggregation,severalapproaches (Amgoudetal.,2005;Bonnefon&Fargier,2006)usedproceduresbasedonlyonthenumberorthe strengthofarguments,whileindecisionanalysismanyaggregationprocedureshavebeenproposed. Anotherseminalworktowardstheusageofargumentationframeworksindecision-makingistheone by(Amgoud&Prade,2009)whichproposesanabstractargumentation-basedframeworkfordecision-making.Themodelfollowsa2-stepprocedurewhereatfirsttheargumentsforbeliefsandoptionsare builtandatthesecondstepwehavepairwisecomparisonsoftheoptionsusingdecisionprinciples. Also,ourteamadoptedargumentationframeworkindecision-makingregardingapplicationsfrom theagriculturaldomain(Tamanietal.,2015)and(Yunetal.,2016). Recently,significantresearchontheapplicativesideofCSChasbeendeployed.Forinstance, someweb-basedtoolsforpreferenceaggregationthatallowuserstocreatetheirownpollsandconduct votinghavebeencreated.Theobjectiveofthesewebapplicationsistohelpcollectivedecision-making byfacilitatingthevoting’sprocedureforthenon-experts.Amongthem,thethreemostindicativeones arePnyx(Brandtetal.,2015),Robovote(Merlobetal.,2016),andWhale(Bouveret,2010).Observe thatthesepolltoolsarepurelysocialchoiceorientedandareusedforobtainingacollectivedecision inasinglepoll.Incontrast,ourtoolisadecision-makingtoolthatallowstoderivedecisions,based onpreferencesandjustifications,formultipledecisionproblems. 1.2. our work Ourresultsincludethedesignandtheimplementationofadecision-makingtool,thatwillbeused foragriculturalmaterialvalorization.Ourgoalistodesignasophisticatedtoolthatisadaptedtothe needsofsurveysconductedforagriculturalproblemsandproducesdecisionsbasedonthejustified preferencesoftheagents.Therefore,wedividethetoolintotwomainsystems,i.e.,thesocialchoice systemandthedeliberationsystem.Thesesystemscanactindependentlyorcanbecombinedto supportadecision.ThesocialchoicesystemreliesonCSCtechniquesandallowsforthecomputation ofa“sociallyfair”globalrankingofalternativesthankstotheaggregationofelicitedindividuals’ rankings.Thedeliberationsystemwillprovidetheargumentationframeworkwhichwillallowfor thecomputationofjustificationsontheseindividuals’rankings.Itaimsatallowingthe“correction” of misinformed or incomplete information by using justifications coming from the different agents.Therefore,withtheimplementationofthesetwosystemsweadaptsocialchoicetheoryand argumentationinordertohavebetterdecisions,inthesenseofhavingjustifiedpreferencesandtheir faircollectiveaggregation.Inordertodemonstratethefunctionalityofourtool,wewillapplythe softwareprocedureonadecisionproblemextractedfromanexistinguse-casethatwasconductedfor theneedsoftheEcobiocapproject.Theuse-caseobjectiveistoevaluatetheinterestofconsumersin new-generationpackaging.However,notethat,thisuse-caseisnotrestrictiveontheapplicativeusage ofthesoftwareasweareconsideringamoregeneralframeworkforotherfuturepossibleapplications andhence,thetoolallowsformultipledecisionproblems. 2. PRoBLEM DESCRIPTIoN Weareconsideringtheproblemoftakingadecisionregardingvalorizationoptionsforagricultural materialswiththeaidofCSCandAF.Therefore,theproblemisformulatedasfollows.Asinput, wehaveasetofalternativeoptionsAwhichwillbecalledalternativesandasetofagentsN,that willelicitjustifiedpreferencesonthealternativeoptions.Weareconsideringthecasewherethe agents’preferencesareexpressedbyjustifiedrankings,i.e.,eachagentprovidesatotalorderonthe alternativesandajustificationforthistotalorder.Thecollectionofthelinearordersforalltheagents iscalledthepreferenceprofile.Intheclassicalsocialchoicetheory,theaggregationofthepreferences iscomputedbyavotingrule,i.e.,thepreferenceprofileisreportedtoavotingrule(method),which thensinglesoutthewinningalternativeandtherankingoftheremainingonesorasetofwinners.

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Theagents’preferencesandthejustificationsareusedtobuildtheargumentsandtheargumentation frameworkAF,whoseroleistohelpuselicitthejustifiedpreferences.

Oneshouldnotethatanevaluationgivenbytheagentoverasetofcriteriaforthealternatives canserveasjustificationsfortheagent’stotalorder.Takingthatintoconsiderationwecanseethat criteria-basedjustificationcanserveasaspecialcaseofthemulti-criteriadecision-makingproblem.

3. GENERAL ARCHITECTURE oF THE DECISIoN SUPPoRT SoFTwARE

Inthissectionwearepresentingthegeneralarchitectureofthedecisionsupportsoftware.Ourproposal includesthedesignandtheimplementationofadecision-makingtool,whichissplitintotwomain systems,i.e.,thesocialchoicesystemandthedeliberationsystem.Eachoneofthesystemscanact asastand-alonedecisiontoolbuttheycanalsobelinkedtogetherinordertoprovideadecision.Our tooliscomposedofthefollowingfoursubsystems:thedatacollecting,thevoting,theargumentation andthedecisionsubsystems.

3.1. Data Collecting Subsystem

Thetaskofthissubsystemistoyieldthedataneededasaninputforthevotingsubsystemandthe argumentationsubsystem.Themostcommonwayforagentstorevealtheirpreferencesisthrough surveys.Hence,thissubsystemtakesasinputthesurvey’s“raw”data,i.e.,thepreferencesofthe agentsinanabstractformat,aswellasthejustificationsbehindthesepreferences.Notethatweare consideringdifferentuse-caseswhichhavedifferentformsofsurveysandthereforethissubsystemis survey-orientedandthemethodusedtocomputetheoutputisadaptedeachtimetothesurveyformat. Theoutputofthesubsystemisstructuredinformationwhichcontainsatotalorder(ranking)ofthe alternativesforeachagentwithpotentialjustificationssupportingeachpreference. 3.2. Voting Subsystem Thissubsystem’sfunctionistoprovidemethodsforelectingthe“best”alternatives(and/orcriteria). Usingtheterm“best”,wemeanthealternatives/criteriathatcorrespondtothesociallyfairestoutcome andthatbestreflectthepreferencesoftheagents.Toachievethat,weconsideravotingsettingwhere wefairlyaggregatethesetofagents’preferencesandproducearankingofthealternativesorafixed-sizedsetofequallywinningalternatives.WerefertoCSCtechniques,e.g.,votingrules,inorderto aggregatetheagents’individualpreferences.Manyvotingruleshavebeenproposedinthesocial choiceliteraturewhichtrytosatisfyprominentandfundamentalfairnesscriteria.However,dueto theimpossibilityresultsbyArrow(1950)andGibbard-Satterthwaite(Gibbard,1973;Satterthwaite, 1975)thereisnohopeoffindingavotingrulethatcanbe“perfect”,becauseduetotheseresults somevitalcriteriacannotbesatisfiedallatthesametime.Hence,weproposevariousvotingrules sothatthedecisionmakerwillbeabletoselectamongthem. Insocialchoiceliteraturethesingle-winnervotingrulescanbecategorizedintothescoring methods,e.g.,Borda,whicharebasedonscoringprotocolsandtheCondorcetconsistentrules,e.g., Copeland,whicharebasedonpairwisecomparisons.Condorcetisconsideredasthefoundingfather ofsocialchoicetheoryandproposedthefollowingrule.Analternativexissaidtobeatalternativey inapairwisecomparisonifthemajorityoftheagentspreferxtoy,i.e.,rankxabovey.Analternative thatbeatseveryotheralternativeinapairwisecomparisonistheCondorcetwinner. Thesocial’schoicesystemprojectedarchitectureallowsthedecisionmakertochooseifshe wantstheoutcometobeafullrankingofthealternativesorasetof“best”alternatives.Usinga classicvotingmethodcanhandleonlythecaseofaggregatingtheindividualpreferencestoafull rankingbutdoesnotcoverthecaseoffindingthesetofequallywinningalternatives,i.e.,the“best” alternatives.Hence,werefertomulti-winnervotingrulesthatpermitthefairaggregationofthe individualpreferenceswhenselectingcommittees.Acommitteeisafixed-sizesubsetofalternatives whoareequallywinners.Thegoaloftheserulesisthateveryagentisrepresentedbyacommittee

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memberandthusthesemethodsareappropriateforelectingthebestkalternatives,whenkisthe numberofalternativesinthecommittee.Contrarytothedatacollectingsubsystemwhichisspecific foreachsurvey,thevotingsubsystemisgenerictoolwhichcanbeusedforalltheuse-cases. 3.3. Argumentation Subsystem Theroleofthissubsystemistoprovidethesetofcoherentandcompletepointsofview.Inorderto achievethatweusethejustificationsoftherankingsonalternatives/criteriaofthedifferentagentsand eliminatethroughlogicalargumentationtheinconsistenciesbetweentheagents’preferences.Hence, adeliberationphaseinteractswiththevotingandtheambiguouspreferencesareeliminatedfromthe preferencesoftheagents.Followingthisprocedure,webuildthejustifiedpreferenceprofile,which canserveasinputtothevotingsubsystem. 3.4. Decision Subsystem Theroleofthissubsystemistoprovidearecommendationforthedecisionmakeronthegiven decisionproblemwhichisthefinaloutputofoursoftware.Therecommendationweprovideisthe parameterized(bythedecisionmaker)outcomeofthevotingand/ortheargumentationsubsystem. Figure1showsthearchitectureofthedecisionsupportsoftwareinhighlevel.

4. SoCIAL CHoICE SySTEM

Thesocialchoicesystemisoneofthetwosystemsthatcomposethedecision-makingtoolandcan actindependentlyorincombinationwiththedeliberationsystem.Thesystem’sroleistoprovidea recommendationthatreflectsthesociallyfairestsolution.Thesystemprovidesaquantitativeapproach andselectsthebestalternativeswithregardtotheaggregationoftheindividualpreferences,butifthe decisionmakerdemandsamorequalitativeapproachthenshehastotakeintoaccountthedeliberation phase,hencethedesignofthedeliberationsystemwhichcomplementsthisone.Thesocialchoice systemiscomposedofanimplementationofthefollowingthreesubsystems:thedatacollecting, thevotingandthedecisionsubsystems.Thegeneralarchitectureofourdesigndefinesthatthe communicationbetweenthedatacollectingandvotingsubsystemsisbasedonfilessinceastructured jsonfileistheinputforthevotingsubsystem.Onthecontrary,thevotinganddecisionsubsystems communicateinternallybetweentheJavacode.Inthissectionwepresentourimplementationand

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thefunctionalityofthesocialchoicesystem.ThetoolisimplementedinJavaandweusetheSwing toolkitforcreatingthegraphicalinterface.

4.1. Implementation of the Data Collecting Subsystem

Theroleofthedatacollectingsubsystemisto“transform”therawdatawhichisextractedfrom differentsurveysintothesuitableinput’sformatforthevotingsubsystem,i.e.,structuredinformation foreachoneofthequestions/decisionproblemsofthesurvey.Recallthateachsurveyprovidesus datawhichisrelatedtothepreferencesoftheagentsinanabstractformat.Therefore,themandatory structuredinformationincludesthelistofthealternativesandtheagents’rankingsonthem.Inorder tofixthestructuredinformation,weconstructastructured“json”fileformatwithspecificattributes thatreflectstheformatofthesurveyandhencethevotingsubsystemcanprocessthisfileasinput. Rememberthatrawdatacanhavedifferentformatsdependingontheformatofthesurveys.Hence, weimplementinourcodeseveralfunctionsthatcanhandleseveraldifferentexportformatsofraw datacomingfromLimeSurvey(LimeSurveyGmbH,2003).Theirfunctionalityistotransformthe differentformatsintoauniquestructureddataformat,andhencetothestructuredjsonfile.Weare implementingthetransformationfromLimeSurvey,sinceitisapopularwebserver-basedsoftware whichenablesuserstodevelopandpublishon-linesurveysandcollectresponses,usingauser-friendlywebinterface.Thestructuredjsonfileisdesignedinawaytocorrespondtothestructured dataoftheinputofthevotingsubsystemandincludesalltheinformationofthesurveys.Tothisend, westandardizetheformatoftheinputofthevotingsubsystem(andhencethejsonfile)incaseof futureadditionofnewdatainput.Thestructuredformofthevotinginputpermitstheimplementation ofadditionalfunctionstransformingfromdifferentsurveysformatstothejsonfile.Therefore,the designandtheimplementationofthedatacollectingsubsystemallowsthesocialchoicesystemto havethecapabilityofincludingnewinputformatsaslongasclassesandfunctionsareimplemented thatcanhandlethetransformationofdifferentfileformatstothejsonstandardizedinput.Wehave alsoimplementedadirectcommunicationbetweenthedatacollectingandvotingsubsystems.This extrafeatureisdirectlyimplementedinthedatacollectingsubsystemandthetransformationfrom thecsvfiletothevoting’ssubsysteminputisdoneinternally.Oneshouldnotethatthisisnotour generalapproachbutisincludedinordertofacilitatetheuserandprocessdirectlytheLimeSurvey’s csvfile.Figure2showstheactivitydiagramofthedatacollectingsubsystem.

4.2. Implementation of the Voting Subsystem

Thebasicfunctionalityofthevotingsubsystemistoaggregateagents’preferencesandcomputethe sociallyfairestalternatives.ToachievethatwecreateaJavaclasswhichimplementsthesubsystem’s features.Wedescribetheminthereminderofthissection. 4.2.1. Input Type Therearetwoinputtypesforthevotingsubsystem.Thedefaultfileinput’sformatisastructured jsonfilecontaininginformationaboutthedifferentdecisionproblemsandtheagents’individual preferences.Asinglejsonfilecansupportmorethanonedecisionproblem.Adecisionproblemis definedbythetopicthedecisionmakerdesignates.Hence,eachdecisionproblemcorrespondstoa questionthatdefinesapoll.Therefore,weimplementthejsonfiletoincludeseveraldecisionproblems whenmultiplequestionsonthesamesetofagentsareincludedinthesurvey.Foreachquestionwe includeinthejsonfilethefollowinginformation: • “Questionid”:Auniquenumberforidentifyingbetweenthedifferentdecisionproblems. • “Poll’sQuestion”:Containstheformulationofthedecisionprobleminaninterrogativeformas itisimposedbythedecisionmaker. • “Alternatives”:Thelistofthealternativesthatcorrespondtothespecificdecisionproblem.

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• “Agentscharacteristics”:Containsthecategoriesonwhichtheagentscanbeclassifiedto.The setofagentscanbeclassifiedintodifferentcategoriesaccordingtotheircharacteristics.Inthis fieldthedecisionmakerdefinesallthecharacteristicsthatshewantstobetakenintoaccount forclassifyingtheagents.E.g.,onecategorycanbe“age”. • “Categoriesofagents”:Containsthesub-categoriesoftheabovecategoriesonwhichtheagents canbeclassifiedto,e.g.,forcategory“age”,wecanhavethefollowingsub-categories:“18-25”,”26-35”,”36-49”,”>50”. Foreachagentthefollowinginformationisstoredinthejsonfile: • “Agentid”:Anumberforidentifyingbetweenthedifferentagents. • “ValuesforagentscharacteristicsforQuestionidx”:Containsthepersonalinformation(values) foreachagentcorrespondingtothecategoriesdefinedinthedecisionproblemx. • “Alternativesrankingforquestionidx”:Containsthetotalorderofthealternativesaccording totheagentforproblemx.

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• “Justificationforalternativesrankingforquestionidx”:Containsthereasoningbehindthe individualpreferencesoftheagentoverthealternativesforproblemx. ThesecondinputfileformatisacsvfilederivedfromLimeSurveycontainingtheabovesame informationindifferentformat.Thefirstlineofthecsvfileiscomposedoftheinformationabout thedecisionproblemsandthenthereisalineforeachagentwhichrepresentsthepreferencesand theinformationofthisagent.

4.2.2. Aggregation of Individual Preferences

Thecorefunctionalityofthevotingsubsystemistheaggregationoftheagents’individualpreferences toacollectivepreference.Oursoftwareproposestocomputetheoutputaggregatedrankingusingthe followingvotingruleskeepinginmindtocoverthewholespectrumoftheliterature:Borda,Kemeny-Young,k-approval,ExtendedTideman’ssimplifiedDodgsonandMulti-winnerSTV.Therefore,we implementBordarule(Borda,1781)asanexampleofascoringruleandtheCopeland’smethod (Copeland,1951)asarepresentativeofCondorcet-consistentrules.Wealsoimplementk-Approval (Brams&Fishburn,1978)becausewewanttocoverthecasewherethepreferencesoftheagents includeasetofequally“accepted”setofalternativesinsteadofatotalorderonthem.Wealso implementtheExtendedTideman’ssimplifiedDodgsonrule(Caragiannisetal.,2014)fromthenew generationofrulesthatweredeployedrecentlyintheCSCliteraturetoovercomethecomputational complexityissuesoftheotherrules.Thisrulehastheadvantageofbeingpolynomialtimeandthus canbecomputedonanyinputsize.Inaddition,weproposeamulti-winnervotingrule,i.e.,the multi-winnerSTV,inordertoaggregatetheagents’individualpreferencestoasetofequallywinning alternatives.Adefinitionoftheimplementedrulesfollows. • Borda’s Count:Itisascoring-basedvotingrule.Itisoneofthesimplestandmostintuitive scoringrules,whereeachalternativereceivesfrom0tom-1pointsfromeachagent,wherem isthetotalnumberofalternatives.Theprotocolisthatthealternativewhichisrankedinthek-th positionbyagentireceivesm-kpointsfromthisagent.ThetotalBordascoreofeachalternative istheaccumulationofallthepointsreceivedfromtheagents.Thealternativewiththehighest accumulatedscorewinsandtherestofthealternativesarerankedaccordingtotheirscore. • k-Approval:Eachagent“approves”(i.e.,selects)koutofmalternativesandeachoneofthem gets1point.Theapprovalscoreofanalternativethenisthecumulativenumberofthepointsshe receivesfromalltheagents.Inallapprovalrules(includingpluralityandveto)thealternative withthehighestscorewinsandtherestofthealternativesfollowaccordingtotheirscore.For k=1weobtainthePluralityrule,whichisoneofthesimplestandmostfundamentalrulesin thehistoryofSocialChoice.Also,fork=m-1weobtainVetowhereeachagentapprovesallbut onealternative.Theintuitionisthateachagentposesherdisapproval(veto)ononealternative. • Copeland:InCopeland’srulealternativesarecomparedpairwise.Whenanalternativeispreferred bythemajorityoftheagentsshereceivesonepointandtheotheralternativereceiveszeropoints. Incaseofatie,intheclassicalversionofCopeland’srulebothreceive0.5points.Thesumover thepointsiscalledtheCopelandscore.Winner(s)arethealternativeswithmaximumCopeland scoreandtherestfollowaccordingtotheirscore.

• Extended Tideman’s Simplified Dodgson Rule:Thisruledependsalsoonpairwisecomparisons betweenalternativesandisbasedonthewell-knownvotingruleofDodgson(Black,1958).Since Dodgson’sruleishardtocomputewechoosethisrulebecauseitisaDodgson’sapproximation algorithmwhichcanbeefficientlycomputed.ThisruleisanextensionofTideman’sruleandthe scoreofeachalternativexisdefinedasfollows.IfanalternativeisawinnerundertheCondorcet methodthenherscoreis0,otherwiseherscoreiscomputedbythefollowingformula:

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sc(x)=m∙sctd(x)+m(logm+1), wheremisthetotalnumberofthealternativesand sctd(x)= y alts x k l

{ } −

{

}

.\ max ,0 . wherekisthenumberofagentsthatpreferyoverxandlisthenumberofagentsthatpreferxover y.Thealternativewiththeminimumscorewinsandtherestofthealternativesarerankedaccording totheirscore. • Multi-Winner STV:Thisrulebelongstomulti-winnervotingruleswhicharedesignedfor selectingafixedk-sizedcommitteeofalternatives,i.e.,thesetofk-winningalternatives.Hence, multi-winnerSTVisthemostappropriateruletobeusedwhentheoutputselectionissettok-top alternatives.TheSingleTransferableVoterule(STV)executesaseriesofiterations,untilitfinds kwinners.Asingleiterationoperatesasfollows:IfthereisatleastonecandidatewithPlurality scoreatleastq=⌊n/(k+1)⌋+1,thenanalternativewiththehighestPluralityscoreisaddedto thecommittee;thenqvotersthatrankherfirstareremovedfromtheelection(arandomizedtie-breakingplaysanimportantrolehere),andtheselectedalternativeisremovedfromallvoters’ preferenceorders.Ifthereisnosuchalternative,thenanalternativewiththelowestPlurality scoreisremovedfromtheelection(again,tiesarebrokenuniformlyatrandom).ThePlurality scoresarethenrecomputed. Asnotedpreviously,thereisno“best”votingruleandonthesameinput,i.e.,thepreference profileoftheagents,differentvotingrulescancomputedifferentaggregatedrankingsasoutput, leadingtotheneed,forthedecisionmaker,tobeabletochoosethevotingruleusedforcomputation. Inthefollowingexampleweareshowingthatphenomenon. • Example.Letusconsiderthefollowingindividualpreferencesfortheagents.Wehave55agents withthefollowingrankings.Weshouldnoteherethatx>yindicatesthatanagentprefersxtoy. • 18agents:A>D>E>C>B • 12agents:B>E>D>C>A • 10agents:C>B>E>D>A • 9agents:D>C>E>B>A • 4agents:E>B>D>C>A • 2agents:E>C>D>B>A Wearenowapplyingthefollowingdifferentvotingrulesandobtainthecorrespondingresults. • Borda:AlternativeDwinswith(18x3)+(12x2)+(10x1)+(9x4)+(4x2)+(2x2)=136points.A gets72,B101,C107andE134. • 1-Approval (Plurality):Here,Awins,with18votes.AlternativesBtoEhavescore12,10,9 and6respectively. • ForTideman’sandCopeland’srulesweobservethataCondorcetwinnerexistssosheisalso thewinnerundertheserules.AlternativeEistheCondorcetwinnersinceshebeatseachofthe otherfouroptionsinpairwisecomparisons,i.e.,EbeatsA37-to-18,B33-to-22,C36-to-19, andD28-to-27.

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• ForMulti-WinnerSTVsupposethatwewantthebest3alternatives,sowefixk=3.Ahasplurality scoreof18whichisatleast⌊55/(3+1)⌋+1=14,soAisincludedinthewinningalternativesand the18votersthatrankAfirstareremovedfromtheelection,andalsoAisremovedfromall voters’preferenceorders.Bhaspluralityscoreof12whichisatleast⌊37/(3+1)⌋+1=10,soB isalsoincludedinthewinningalternativesandthe12votersthatrankBfirstareremovedfrom theelection,andalsoBisremovedfromallvoters’preferenceorders.Chaspluralityscoreof 10whichisatleast⌊25/(3+1)⌋+1=7,soCisalsoincludedinthewinningalternatives.Hence, A,BandCarethewinners.

• Incomplete (Truncated) Preferences:Itisthecasewhereagentsdonotprovideacomplete rankingofthealternatives.Thiscanhappenwheneachagentislikelytoknowwhohermostfavorite alternativesarebutsheisunwillingtoputtheeffortintorankingtheremainingones.Then,itissafe toassumethatshelikesthemlessthantherankedonesbutamongtheunrankedonesthereisno differenceinpreference.Weusethisassumptionwhencomputingthecollectivepreferencesunder incompletepreferences.Therefore,thetypicalvotingrules,liketheabovementioned,havetobe adjustedtocoverthiscase.Forexample,forBorda,wecouldassumethateachunrankedalternative receives0pointsfromagivenvote(amethodusedinSlovenia,whichiscalledpessimisticscoring model).AnothermethodforBordaistheoptimisticscoringmodel,whereiftherearemalternatives butavoteranksonlykofthem,thentherankedalternativesgetm−1, . . ., m−kpoints(depending ontheirpositionintheranking)andeachunrankedalternativegetsm−k−1points.Wewillusethe pessimisticmodelinourcomputationforBordabecauseitismorewidelyused.Fork-approvalif thepreferencesoftheagentsareincompletebutmorethankalternativesarerankedthenthereis nodifferenceandonthecontrarywhenlessthankalternativesarerankedbytheagent,thenall getonepoint.Fortherulesbasedonthepairwisecomparisonsweassumethatifanalternativeis rankedandtheotherisnot,thenthewinneristheonerankedandwhenbothareunrankedwedo nottakeintoaccountthiscomparison.Figure3showstheactivitydiagramofthevotingsubsystem andFigure4showsthediagramofthedecisionsubsystem.

4.3. Implementation of the Decision Subsystem

Theobjectiveforthedecisionsubsystemistoprovidearecommendationforthedecisionmaker. Theoutput(decision)willbebasedontheaggregationoftheindividualpreferencesbutmaycontain differentresultsaccordingtotheparametersthatareimposedbythedecisionmaker.Toachievethat wecreateaJavaclasswhichimplementsdifferentfeatures,whichwecalldecision-aidingfeatures. Thereisalinkintheimplementationofvotinganddecisionsubsystemssincedecision-aidingand votingfeaturesinteract.Thedecisionmakercanchooseamongstdecision-aidingfeaturesthatcanbe classifiedinto3categoriesaccordingtothecomputationphaseinwhichtheybelongto. 4.3.1. Voting Phase Thefirstparameteronwhichthedecisionmakercanbaseherdecisionisthechoiceoftheappropriate votingrule.Thedecisionmakercanthereforechooseoneormoreoftheabovementionedrule(s) accordingtoherneedsandobtaindifferentdecisions,sincedifferentrulesonthesamepreference profilecanleadtodifferentcollectiverankings. 4.3.2. Aggregation Phase Duringthedecision-makingprocedurechoosingtherightvotingruleisnottheonlycrucialmatter inordertosupportadecision.Thedecisionmakerisprovidedwithdifferentaggregationprocedures thatcanhelphertakeabetterdecisionaccordingtotheneedsoftheproblembyeithertakingasubset oftheagentspreferencesor/andincreasingtheweightoftheopinionofsomeagents.Thepreference profilecanbepartitionedindifferentsubsetswhenagentssharecommoncharacteristics.When agentsbelongtothesamesubsetwesaythattheybelongtoaspecificcategory,e.g.,agentscanbe

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partitionedaccordingtosexandhencewehavetwocategories,i.e.,maleandfemale.Itisthereforethe preferenceprofilewhichistakenastheinputtheonethatdifferentiatestheaggregationprocedures. Thedecisionmakercanalsocombinecategoriesinordertogetthepreferenceprofilefortheinput (combinationofcategories).E.g.,thedecisionmakercanchooseherinputtobemenaged18-35.To getthedesiredinput,thesoftwareallowstheoptiontocombinecategories“Sex:male”and“Age: 18-35”.Therefore,weproposethefollowingdecision-aidingaggregationprocedures. • Total Aggregation:Thedecisioniscomputedtakingintoaccountallagents’preferences. • Aggregation per category:Inthisproceduretheagentsareforminggroups(subsets)according

totheirclassificationondifferentcategories.Therefore,weapplyavotingrulehavingasinput thepreferenceprofilethatcorrespondstoagentsbelongingonlyonthespecified,bythedecision maker,category(orcombinationofcategories). • 2-Phase Aggregation:Also,inthisproceduretheagentsareforminggroupsaccordingtotheir category.Inthefirstphasearankingforeachoneoftheagents’categories(subsets)iscomputed byapplyingavotingrule.Inthesecondphasethedecisionisthecollectivepreferencecomputed

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bytheaggregationoftherankingsproducedduringthefirstphase.Forbothstepsweareusing thesamerule.Weconsiderthateachoneoftheagents’typeshasequalsay(i.e.,weight)tothe collectivepreference.

• 2-Phase Aggregation with Weights:Itissimilartotheaboveprocedurebutinthiscasewedo notconsiderthateachoneoftheagents’typeshasequalsaytothefinalcollectivepreference. Insteadweprovidethedecision-makertheabilitytodefinetheweightsforthedifferentcategories accordingtotheneedsofthedecisionproblem.Thefinalrankingiscomputedbytheproportional, accordingtotheweights,aggregationofthevotesofeachcategory. 4.3.3. Output Phase Duringthisphasethedecisionmakercanbaseherdecisionondifferenttypesofoutput.Theoutput producedbythetoolcanhavethefollowingforms. • Single Winner:Therecommendationthatisprovidedtothedecisionmakeristhewinning alternativeaccordingtothespecifiedrule.Incaseofatiewecanhavemultiplewinners.

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• k-Top Alternatives (Committee Size):Therecommendationisacommitteeofsizek,which correspondstothesetofthebestkalternatives.Amulti-winnervotingruleisused.

• Rank:Therecommendationisprovidedintheformofacompleterankingoverthealternatives.

4.4. Graphical User Interface

Thegoalofourdecisionsupportsoftwareistobeusedbydecision-makerswhicharenon-voting experts.Takingthisgoalintoaccount,weimplementagraphicaluserinterface(GUI)which correspondstothefunctionalitiesdescribedinthesubsystems.WebelievethattheGUIisuser-friendly andpermitsthedecisionmakertoexploreallthefunctionalitiesintermsofpreferenceaggregation andachieveadecisionbasedonherneeds.AscreenshotoftheGUIisshowninFigure5. Theusageofthetoolcanbeseenthroughthelayoutoftheinterfacewhichisthefollowing.On theupperpartoftheapplicationwedepictthedatacollectingsubsystemwheretheusercanload thesurvey’sfile(csv)orthevotinginputfile(json).Rightbeneathisthetranslatorwhereonecan transformthesurveycsvfileintothejsonfileformatwhichisappropriateforinputtothevoting subsystem.InthemiddlepartoftheGUIthevotingsubsystemisbeingvisualizedwherethedecision makercanchoosethevotingrulethatisgoingtobeusedfortheaggregationofthepreferenceprofile.

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Thedecisionmakerhastheoptiontochooseamongdifferentrulesandmayobtaindifferentresults. Theninthelowertwopanelsthedecisionsubsystemisbeingshown,wherethedecisionmakercan choosetheaggregationandoutputtypes.Inordertoselecttheaggregationtypesanewwindow appears(Figure6).Inthisexamplethedecisionmakertakesintoaccountonlytheagentsaged26-35. Theoutputofthecomputationisdepictedinatextform.Thedecisionmakercanchoosethrough theinterfacetheparametersshewantstoimposeandhenceobtainthecorrespondingresults.The subpartoftheinterfacefortheresultsisdepictedinFigure7.Wealsoprovidetheoptiontosavethe resultsinatextfile.

5. EXAMPLES oN REAL DATA: PACKAGING CHoICE DECISIoNS FoR ECoBIoCAP AND oPINIoN ANALySIS

Inordertodemonstratetheusabilityofourtoolandvalidatethepresentedmethodologywestudy real-datadecisionproblemsonfoodpackagingselection.Thestudieddecisionproblemaimsat recommendingrelevantalternatefoodpackagingbasedonmultiplecriteria.Onecriticalfactorin recommendingnewpackagingistheopinionoftheconsumers.Therefore,weapplyourtooltothis problemandobtainthepreferencesoftheagentsfromacasestudywhichisextractedfromasurvey thatwasconductedinanationallevelforFrancefortheneedsoftheEcobiocap(ECOefficient BIOdegradable Composite Advanced Packaging) project. This survey is related to different functionalitiesregardingfoodpackagingwhere235citizenshelpedbyansweringthequestions. Therefore,weusethissurveyforcollectingthedata,i.e.,thecitizens(agents)preferencesandthe justifications,andansweringinthenextstepthedecisionproblem.Oneshouldobservethatusingour appliedprocedureontheseexamplesisnotrestrictiveontheapplicativeusageofoursoftwaresinceit isdesignedasamoregeneralframeworkwhichcansupportfuturepossibleapplicationsandproblems.

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Thefirstcategoryofproblemsincludedinthissurveyconsistsinfindingthebestalternativesfor foodpackagingondifferentkindsoffoods.Hence,thecitizenswereaskedtogivetheirpreferences ondifferentquestionsregardingcheese,fruits&vegetablesandsandwichpackaging.Thesequestions correspondtodifferentdecisionproblems(foreachtypeoffood)astheagentsevaluatedandranked thealternativesforeachquestionseparately.Thealternativeoptionsgiventoberankedbyeachagent weretransparent,translucentandopaque. Theseconddecisionproblemonwhichtheagentswereaskedtogivetheiropinionconcerns thetypeofthematerialforfoodpackaging.Therefore,eachagentgaveherpreferenceonthetype ofthematerialsheprefersforproducingthefoodpackaging.Theagentshadtochoosebetweentwo alternativesforthisproblem,i.e.,bio-source(inparticular,usingagriculturalby-productstoproduce thepackaging)andpetro-source. Forthenextdecisionproblemeachagenthadtoanswerifsheapprovestheusageofclay nanoparticlesforthecompositionofthefoodpackaging.Theagentshadtochoosebetweenyesandno. Thelastdecisionproblemisrelatedtotheend-of-lifemanagementofthefoodpackaging.The agentsgavetheirpreferencesonthetypeoftheend-of-lifetheypreferforthepackagings.Forthis problemthesetofalternativeswere:recycling,composting,biodegradationandincineration.Figure 8showsmulti-criteriadecisionsupportresultsinterface.

5.1. Preference Aggregation for Ecobiocap’s MCDSS

Inthisapplication,thesocialchoicesystemcomputedaggregatedpreferencesassociatedwithdifferent populationsforspecificfoodpackagingcharacteristics.Then,thoseaggregatedpreferenceshavebeen usedasinputparametersforamulti-criteriadecisionsupportsystem-calledMCDSS(Destercke etal.,2011;Guillardetal.,2015)whichretrievesthemostrelevantpackagingforagivenfood.In thefollowing,wepresenttheresultsobtainedforcheesepackagingregardingtransparency.Using individualpreferencesexpressedby235citizensintheEcobiocapsurvey,ourtoolhascomputedthe followingaggregatedpreferences:

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• Case 1:Frenchpopulationasawhole(235votes):transparent>translucent>opaque • Case 2:peoplelivinginIledeFrance(46votes):translucent>transparent>opaque TheMCDSShasbeenusedtwicetoretrievethemostrelevantpackagingtopackasoftcheese fromrawewe’smilk(250grams,shelflifeof14days,storageatambienttemperature)using preferencesassociatedwithpopulationsofcases1and2.ForCase1,thebestpackagingisaMC(L) PolysaccharideasforCase2,thebestoneisaHPC/LipidsPolysaccharide.Thecompletelistofmost preferredpackagingforCase2ispresentedinthe“Packagingranking”windowinthelowerpartof Figure8.Thoseresultshavebeenpresentedtostakeholdersofthefoodpackagingchainduringthe CIAGconference(Bucheetal.,2017).

5.2. opinion Analysis as A Powerful Tool for Decision-Making

Anotherpossibleuseofthesystemistoproviderecommendationstothedecisionmakerfordesigning potentialfoodpackagingstakingintoaccountthecitizensopinion.

Theresultsrevealedthatforthetypeofpackagingthecitizenspreferforcheese,fruits&vegetables andsandwichthetransparentisrankedhigherthantranslucentwhileopaqueisthelastoneinall butthepluralityrule.Inthecaseof2ormorealternativespluralityisnotconsideredanappropriate

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methodbysocialchoicetheorists.Hence,therecommendationprovidedtothedecisionmakeristhan citizensprefertransparenttotranslucenttoopaque. Regardingtheseconddecisionproblem,theresultsrevealedthatinthecollectivepreferenceof thecitizensforthetypeofthematerialtheypreferforproducingthefoodpackagingthebio-source isrankedhigherthanpetro-source.Thesameresultappearedwhenallthevotingruleswereusedfor theaggregationoftheirindividualpreferences.Hence,therecommendationprovidedtothedecision makeristhancitizenspreferbio-sourcetopetro-source. Forthedecisionproblemconcerningtheusageofclaynanoparticlesforthecompositionoffood packaging,weusedpluralityandtherecommendationprovidedtothedecisionmakeristhancitizens donotprefertheusageofclaynanoparticles. Theresultsforthelastdecisionproblem,whichcorrespondstotheend-of-lifeforpackaging, revealedthefollowingsamerankingfortherulesofBorda,Tideman’sandCopeland:recycling, composting,biodegradationandincineration.Usingpluralityweobtainedaslightdifferentranking: recycling,biodegradation,composting,andincinerationbutobservethatthewinnerisstillthesame underallvotingrules.Inthiscasewehavefouralternativessowewillnotusetherankingprovided bypluralityandhence,therecommendationprovidedtothedecisionmakeristhancitizensprefer recyclingtocompostingtobiodegradationtoincinerationfortheend-of-lifeforfoodpackaging. Summinguptheresultsofalltheabovedecisionproblemsthedecisionprovidedbythecollective preferencesofthecitizensisthattheypreferafoodpackagingthatsatisfiesthefollowingfeatures.It shouldbetransparent,madeofbio-sourcematerialswithouttheuseofclaynanoparticlesandshould alsoberecyclable. Also,basedonthedecisionmakerparametersthefollowinginterestinginsightsappearedwhen usingdifferentvotingrulesandaggregationtypesfortheaggregationoftheindividualpreferences. Thefirstcategoryoftheobservedinsightsinrealdataexamplesconcernsthediscrepanciesforthe samepreferenceprofilewhenadifferentvotingmethodwasused.Forexample,asalreadymentioned thecaseofpluralitycomparedtotheothervotingrules.Thesecondcategoryofinsightsobservedare theonesrelatedtotheaggregationwhendifferentsubsetsofcitizens(i.e.,partitionsofthepreference profile)weretakenintoaccount.Wemakethefollowinginterestingobservations.Notethatallthe remarksthatwemakebelowrefertocomputationunderthesamevotingrule. • Observation 1:Fortheproblemoftheend-of-life,thecollectiverankingaccordingtodifferent sexisdifferentwhenmenarecomparedtowomen.Thecollectivepreferenceofthe91men includedinthesurveyis:recycling,biodegradation,compostingandincineration.Ontheother hand,143womenvotedforthesurveyandtheircollectiverankingis:composting,recycling, biodegradationandincineration. • Observation 2:Forthesameproblemdifferentresultsarealsoobtainedifwechangethecategory ofaggregationtoage.Alltheagegroupsexcepttheonesover50,i.e.,“18-25”,“26-35”,“36-49”, havethesameranking:recycling,composting,biodegradationandincinerationwhilepeopleover 50havecomposting,biodegradation,recyclingandincineration. • Observation 3:Theend-of-lifeproblemisnottheonlyonewithinterestinginsights.For theproblemofcheesepackagingwealsoobtaindifferentrankingswhendifferentsubsetsof thepreferenceprofileareused.Forexample,citizenslivingintheHeraultdepartmenthave thefollowingpreference:transparent,translucent,opaquewhilepeoplelivinginParishave: translucent,transparent,opaque. Therefore,wecanseeinpracticethatcollectivepreferenceschangeaccordingtoapartitionofthe preferenceprofileusedastheinput.Therefore,weprovidethepartitioningofthepreferenceprofileas animportanttooltothedecisionmakerinordertosupportherdecisionwhenthenatureofthedecision problemisdrivenbydifferentconstraints.Forexample,ifthedecisionmakerisonlyinterestedfor producingacheesepackagingthatwillonlybesoldinParisthensheshouldrelyherdecisiononly

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onthepreferencesoftheagentsthatliveinParis(observation3).Webelievealsothatthe2-phase aggregationisareallyimportanttoolforthedecisionmakeraswestateinthenextobservation. • Observation 4:Fortheend-of-lifeproblemwecanseethatpeoplelivinginHeraulthave differentpreferencesfrompeoplelivinginParis.PeoplefromHeraultpreferrecycling> composting>biodegradation>incinerationwhilepeoplefromParisequallyprefercomposting andbiodegradationtorecyclingandincineration.Thetotalofaggregationofthealltheagents producesthecollectiveranking:recycling>composting>biodegradation>incinerationwhich isthesameastheHerault’scollectiveranking.Thisisduetotheratioofthestatisticalsample whichisnotproportionaltotherealpopulationratiobecauseinthesurveywehad137agents votingfromHeraultand14fromParis.However,ifthedecisionmakerwantsafairestsolution accordingtothepopulationratioshecanadjusttheweightsofthevoterslivingindifferentregions. Hence,ifweassumeweightof12toPariscomparedto1forHerault(12millioninhabitants versus1million)thenthefollowingcollectiverankingiscomputed:composting>biodegradation >recycling>incineration.Notethat,wealsoassignzeroweighttotheotherdepartmentssince thestatisticalsampleissmallforthem.

6. CoNCLUSIoN AND FUTURE woRK

Inthispaper,wehaveproposedasoftwaretoolfordecision-makingforissuescomingfromagricultural engineeringwiththeaidofComputationalSocialChoiceandArgumentationFramework.Wedescribe thoroughlythesocialchoicesystemofthedecisionsupportsoftwareanddemonstrateditsapplication onareal-dataexampleinthecontextofEcobiocapprojectwheretheobjectiveistofindthebestfood packagingintermsofmaterial,visibilityandend-of-life. Asfuturework,wewanttofurtherextendourresearchtowardstheintegrationofArgumentation andSocialChoicefor“better”decisions.Hence,ourgoalistodesignandimplementthedeliberation systemwhichwillcompletethedecisionsupportsoftware. ACKNowLEDGMENT WethankMadalinaCroitoruforhercontributioninthegeneraldesignofthedecisiontoolandfor herhelpindrawingFigure1.TheresearchleadingtotheseresultsispartofNoAWprojectthathas receivedfundingfromtheEuropeanUnion’sHorizon2020researchandinnovationprogrammeunder grantagreementNo688338.TheresearchwaspartiallyimplementedwithascholarshipfromIKY fundedbytheaction``SupportofPostdoctoralResearchers’’fromtheresourcesoftheEP“Human ResourcesDevelopment,EducationandLifelongLearning”withpriorityaxes6,8,9andisandco-fundedbytheEuropeanSocialFund-ESFandtheGreekstate.

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Amgoud,L.,&Prade,H.(2009).‘Usingargumentsformakingandexplainingdecisions’.Artificial Intelligence, 173(3-4),413–436.doi:10.1016/j.artint.2008.11.006

Arrow,K.,&Raynaud,H.(1986).Social choice and multicriterion decision making.Cambridge:MITPress. Arrow,K.J.(1950).Adifficultyintheconceptofsocialwelfare.Journal of Political Economy,58(4),328–346. doi:10.1086/256963

Benayoun,R.,Roy,B.,&Sussman,B.(1966).ELECTRE: une méthode pour guider le choix en présence des points de vue multiples(technicalreport).SEMA-METRAInternational.

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Bonnefon,J.F.,&Fargier,H.(2006).Comparingsetsofpositiveandnegativearguments:Empiricalassessment ofsevenqualitativerules.Frontiers In Artificial Intelligence And Applications,141,16.

Borda,J.-C.d.(1781).Mémoire sur les élections au scrutin.Histoiredel’AcademieRoyaledesSciences. Bouveret,S.(2010).Whale4:Whichalternativeiselected.Retrievedfromhttp://strokes.imag.fr/whale4

Brams,S.J.,&Fishburn,P.C.(1978).Approvalvoting.American Political Science Review,72(3):831–847,009. Brandt,F.,Chabin,G.,&Geist,C.(2015).Pnyx:APowerfulandUser-friendlyToolforPreferenceAggregation. InProceedings of the 2015 International Conference on Autonomous Agents and Multiagent Systems(pp.1915-1916).InternationalFoundationforAutonomousAgentsandMultiagentSystems.

Buche,P.,Gontard,N.,Guillard,V.,Guillaume,C.,&Menut,L.(2017).Outild’aideàlasélectiond’emballages alimentairespourlaconservationsousatmosphèremodifiéedesproduitsfrais.Innovations Agronomiques, 58, 81-91.Retrievedfromhttps://prodinra.inra.fr/record/416054

Caragiannis,I.,Kaklamanis,C.,Karanikolas,N.,&Procaccia,A.D.(2014).Sociallydesirableapproximations forDodgson’svotingrule.ACM Transactions on Algorithms,10(2),1–28.doi:10.1145/2556950

Copeland,A.(1951).A“reasonable”socialwelfarefunction.Seminar on applications of mathematics to social sciences. Destercke,S.,Buche,P.,&Guillard,V.(2011).Aflexiblebipolarqueryingapproachwithimprecisedataand guaranteedresults.Fuzzy Sets and Systems,169(1),51–64.doi:10.1016/j.fss.2010.12.014

Fox,J.,&Parsons,S.(1997).Onusingargumentsforreasoningaboutactionsandvalues.InProceedings of the AAAI Spring Symposium on Qualitative Preferences in Deliberation and Practical Reasoning(pp.55–63).AAAIPress. Gibbard,A.(1973).Manipulationofvotingschemes:Ageneralresult.Econometrica,41(4),587–601. doi:10.2307/1914083

Guillard,V.,Buche,P.,Destercke,S.,Menut,L.,Guillaume,C.,&Gontard,N.(2015).ADecisionSupport Systemfordesigningbiodegradablepackagingforfreshproduce.Computers and Electronics in Agriculture, 111,131–139.doi:10.1016/j.compag.2014.12.010

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Figure

Figure 1. The architecture of the decision support software in high-level
Figure 2. The activity diagram of the data collecting subsystem
Figure 3. Activity diagram of the voting subsystem
Figure 4. Activity diagram of the decision subsystem
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