From Organisational Structure to

1FromOrganisationalStructuretoOrganisationalBehaviourFormalisation*CatholijnM.JonkerandJanTreur1VrijeUniversiteitAmsterdam,DepartmentofArtificialIntelligenceDeBoelelaan1081a,NL-1081HVAmsterdam,TheNetherlandsEmail:{jonker,treur}@cs.vu.nlURL:~{jonker,treur}AbstractTounderstandhowanorganisationalstructurerelatestoorganisationalbehaviourisaninterestingfundamentalchallengeintheareaoforganisationmodelling.Specificationsoforganisationalstructureusuallyhaveadiagrammaticformthatabstractsfrommoredetaileddynamics.Dynamicpropertiesofagentsystems,ontheotherhand,areoftenspecifiedintheformofasetoflogicalformulaeinsometemporallanguage.Thispaperaddressesthequestionhowthesetwoperspectivescanbecombinedinoneframework.Itisshownhowfordifferentaggregationlevelsandotherelementswithinanorganisationstructure,setsofdynamicpropertiescanbespecified.Organisationalstructureprovidesastructureof(interlevel)relationshipsbetweenthesemultiplesetsofdynamicproperties.Thusorganisationalstructureisreflectedinformalisationofthedynamicsoforganisationalbehaviour.Asanillustration,fortheAGRorganisationmodellingapproachitisshownhowaformalfoundationcanbeobtainedforintegratedspecificationofbothstructureandbehaviourofanorganisation.1IntroductionSocietiesarecharacterisedbycomplexdynamicsinvolvinginteractionbetweenlargenumbersofactorsandgroupsofactors.Ifsuchcomplexdynamicstakesplaceinancompletelyunstructured,incoherentmanner,anyactorinvolvedhasnotmuchtorelyontodoprediction,andisnotabletofunctioninaknowledgeablemanner.Thishasseriousdisadvantages,whichisareasonwhyinhistorywithinhumansocietiesorganisationalstructurehasbeendevelopedasameanstomanagecomplexdynamics.Organisationalstructureprovidesco-ordinationoftheprocessesinsuchamannerthataprocessoragentinvolvedcanfunctioninamoreadequatemanner.Thedynamicsshownbyagivenorganisationalstructurearemuchmoredependablethaninanentirelyunstructuredsituation.Itisassumedthattheorganisationalstructureitselfisrelativelystable,i.e.,thestructuremaychange,butthefrequencyandscaleofchangeareassumedlowcomparedtothemorestandarddynamicsthroughthestructure.WithinthefieldofOrganisationTheorysuchorganisationalstructuresregulatingsocietaldynamicsarestudied;e.g.,[29],[37].Insummary,organisationalstructureisusedtoobtaindynamics(ororganisationalbehaviour)ofadesiredtype.Forfurtheranalysisacrucialissuehereishowexactlyaformalisationoforganisationalstructureisabletoaffectformalisationoforganisationaldynamics.Thisimpliesinparticularthatasafoundationforanappropriateapproachtoorganisationmodelling,boththestructuralaspectsandthedynamicaspectsandtheirrelationhavetobe*Apreliminary,shorterversionofthisworkwaspresentedattheThirdInternationalWorkshoponMulti-AgentBasedSimulation,MABS'02.2formalisedinanappropriatemanner.Multi-agentororganisationmodellingapproacheshavebeendevelopedinthreemanners.Firstly,informalorsemi-formalgraphicalrepresentationsoftheorganisationalstructurehavebeendeveloped;i.e.,pictureswithboxesandarrows;e.g.,[37].Suchorganisationmodels,althoughtheyprovideadetailedaccountoftheorganisationstructure,remainonaratherabstractlevel.Inparticulartheydonotgiveindicationshowthemoredetaileddynamicstakesplace;itdoesnotspecifyhowthesestructuresrelatetodynamics.Secondly,withintheareaofComputationalOrganisationTheoryandArtificialIntelligence,anumberoforganisationmodellingapproacheshavebeendevelopedtosimulateandanalysedynamicswithinorganisationsinsociety;e.g.,[39],[32],[38],[12],[16],[23],[26].Someoftheseapproachesexplicitlyfocusonmodellingorganisationalstructure,abstractingfromthedetaileddynamics.Otherapproachesputlessemphasisonorganisationalstructurebutfocusonthedynamicsinthesenseofimplementingandexperimentingwithsimulationmodels.Oftenthesesimulationmodelsarebasedonsomeimplementationenvironmentandnotspecifiedinanimplementation-independentmannerusingaformallydefinedconceptuallanguage.TheStrictlyDeclarativeModellingLanguageSDML[38](seealso[9]),andtheuseoftheagent-orientedmodellingapproachDESIREinsocialsimulationaspresentedin[8]aresomeofthefewexceptions.Bothmodellingapproachesfocusonspecificationandsimulation;however,theydonotofferdedicatedsupportforaspecifictypeoforganisationalstructure.Moreover,simulationofdynamicsisthemainpurpose;notmuchformallydefinedsupportisofferedforanalysisofdynamics,suchascheckingwhetheragivensimulationorempiricaltracesatisfiesagivendynamicproperty.Thirdly,temporalmodellingisoneofthedominantapproachesforspecificationandanalysisofdynamicpropertiesinagentsystemsingeneral;e.g.,[1],[9],[15],[16],[17],[28],[33],[35],[38];seealso[18],[19]foranoverview.Oneofthestrongpointsinthisareaofresearchisthedeclarativemodellingofsimulationmodels,forexamplebasedontheparadigmofExecutableTemporalLogic[1].Alsoformalanalysis(verification)canbesupportedusingthistypeofformalisation;e.g.,[9],[16],[33],[35].However,thetemporallanguagesorlogicsusuallyadopteddonothavemeanstoexplicitlyreflectorganisationalstructureinanorganisationalbehaviourspecification.TheAgent/Group/Role(AGR)approach(previouslycalledAalaadin)introducedin[12]isanexample