The RETSINA Multiagent System: Towards Integrating Planning, Execution and Information Gathering Anandeep S. Pannu The Robotics Institute Carnegie-Mellon University Pittsburgh, PA 15213
[email protected],(412) 268 7598
Katia Sycara The Robotics Institute Carnegie-Mellon University Pittsburgh, PA 15213
[email protected],(412) 268 8825 1 ABSTRACT
2 INTRODUCTION
This videopresentationdescribesthe RETSINA (Reusable Task StructureBasedIntelligent Network Agents)framework, explicatesthe unifying organizationaland architecturalideasanddemonstrates theirapplicabilityto variousdynamicdomains(e.g. FinancialPortfolioManagement,DistributedCalendarScheduling,SatelliteVisibility Tracking). The architectureof a singleagentas well as the coordination strategiesthat the agentsuseare presentedin somedetail , RETSINAis a flexibleframeworkthat enablesagents to dynamicallyform agentteams“on-demand”to solve a problem,takinginto considerationandadaptingto-the user, taskand situation,For example,REISINA agentsmonitor sourcesof stockinformation,financialnews,historicaldata, EDGARdata(EDGARis thedatabasethatkeepsannualand quarterlycompanyearningsreports)and notify the userof relevantchanges,In addition,the agentscollaborateto integratedata from thesedifferent sources. Moreover,they provideadviceto the userregardingprospectivestocksand act on a user’sbehalfperformingstockbuying and selling transactions, The RETSINA group believesthat the next generation of agenttechnologywill heavilyreIy on multiple adaptive coordinatingagentsthat supportusersnot only in gatbering informationbut alsoin makingdecisions,thusproviding advantages far beyondconventionalagenttechnology.This videopresentsthe lessonslearnedin a wide varietyof domains,
The voluminousand readily availableinformationon the Internet has given rise to explorationof Intelligent Agent technoIogyfor accessing,filtering, evamatingand integrating information. In contrastto most currentresearchthat hasinvestigatedsingle-agentapproaches, we aredeveloping a collectionof multiple agentsthat teamup on demanddependingon the user,task, and situation-to access,filter andintegrateinformation,andin additionprovideadviceto usersregardingusertasks.We are investigatingtechniques for developingdistributedadaptivecollectionsof information agentsthat coordinateto retrieve,filter andfuseinformationreIevantto.the user, task and situation,as we11as anticipateuser’sinformationneeds. Our intra-agentarchitectureandinter-agentorganization is basedon theRETSINAmultiagentreusableinfrastructure that we aredeveloping.The RETSINAframeworkis being usedto developdistributedcollectionsof intelligentsoftware agentsthat cooperateasynchronouslyto performplanning, executionand goal-directedinformationretrieval,information monitoringand integrationin supportof performinga varietyof decisionmakingtasks.A collectionof RETSINA agentsform anopensocietyof reusabIeagentsthatselforganize andcooperatein responseto taskrequirements.In particular,we focuson threecrucialcharacteristics of the overall frameworkthat differentiateour work from others.First, RETSINA is an openmulti-agentsystemwherethe agents operateasynchronouslyandcollaboratewith eachotherand their user(s).Agents,informationsourcesandcommunication links mayappearanddisappearunpredictably.Second, the agentsadaptat both the individual level and the organizationalIeveI.Third, informationgatheringis seamlessly integratedwith planning,executionof plannedactionsand informationgathering. EachRETSINA agent’sarchitectureconsistsof: a communicatorthat receivesandparsesmessages, a plannerthat performsdomainspecificproblemsolving,a schedulerthat schedulesexecutableactions,and an executionmonitorthat
1.1 Keywords Agent architectures,multi-agentcommunication,informa-
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monitorsexecutionandinitiatesre-planning.Dueto theuncertaintyand the opennessof the environment,RETSINA agentsfindoneanotherthroughmiddle agents to whomthey advertisetheircapabilities,or sendrequests. 3 RETSINA APPLICATIONS UsingtheRETSINAarchitecturewe havedevelopedseveral applications,PLEZADES is an intelligentagentsystemfor personalproductivityand organizationalintegration.WARREN is a collectionof intelligentagentsfor financialportfolio management, THALES is a satellitevisibility forecasting system, The PLEIADESsystemconsistsof a CalendarApprentiCCD~Cnt(SCChttr,://~~~~.cn.cmu.edu/’softagents/pleiades)
which learnsusers’schedulingpreferences,a Visitor Hoster Agent which helpsschedulevisitorsfor meetingswith faculty at CarnegieMellon Universitywho shareresearchinterests,and a PersonnelInformationAgent which provides informationaboutspecificindividualsand their jobs. The Visitor Hesteragentis an intelligentagentaimedat helping a humansecretaryorganizea visit in an academicenvironment, The task of hostinga visitor involvesarrangingthe visitor’sschedulewith faculty that matchthe intereststhat the visitorhasexpressedin his/hervisit request.The Visitor Honteragentutilizesvariousinformationagentsto retrieve task-relatedinformationfrom severalreal-world heterogeneousdataresources,suchas intemet-basedfinger,on-line electroniclibrary,etc. The WARRENmulti-agentsystemperformsthe taskof providinganintegratedfinancialpicturefor managinganinvestmentportfolioovertime,usingtheinformationresources alreadyavailableover the Internet. This task environment has many interestingfeatures,including 1) the enormous amountof dynamic,uncertainand unorganizedinformation relevantto the task,2) informationtimelinessandcriticality featuresthatpresentthe agentswith hardandsoft real-time deadlinesfor certaintasks,3) resourceandcostconstraints, 4) relativelywell-structuredevaluationcriteria and experimentallyverifiabletest-bedwhere decisionssupportedby the systemcanbe evaluatedusingreal world dataandfeedback, WARREN, currentlyconsistsof a matchmaker, 3 taskagents, 6 informationagentsand(for eachuser)onePortfolioInterfaceagent.Usinga Javabasedinterface,the Portfolioagent displaysthe standardinformationabout a user’sportfolio, allowsthe userto (simulate)buyingandsellingshares,and displaysrecentpricing and newsinformation. It alsoprovidesaccessto the reportsproducedby the two taskagents, eithercontinuouslyupdatedor on demand. The systemprovides1) monitoringover time of stock prices,2) adviseon the managementof a user’sportfolio basedon a profile of the user, 3) graphicalintegrationof
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stockpricesandrelevantnewsstoriesovertimeand4)a simple fundamentalanalysisof a stock with respectto its historicalsalesandearningsdata,alongwith an accompanying graph. The THAIJZSsystemtrackssatellitesandadvisesa user on whetherthesatellitewill bevisiblefor a timeof theuser’s choosing.To do this it hasto integrateinformationaboutthe geographicalcoordinatesof thecity in whichtheuserwishes to view the city, the identity of the satellitethat the user wishesto view, the trajectoryof the satelliteand weather information.It thenadvisesthe useron whetherthesatellite is on a viewabletrajectoryandwhethertheforecastweather permitsviewing of the satellite. It also displaysthe trajectory of the satellitesuperimposedover a map. The system consistsof five informationagentsand a SatelliteVisibility Interfaceagent(for eachuser). 4 WHITHER RETSINA? The RRTSINA group believesthat the next generationof agenttechnologywill heavilyrely on multipleadaptivecoordinatingagentsthatsupportusersnot only in gatheringinformationbut alsoin makingdecisions,thusprovidingadvantagesfar beyondconventionalagenttechnology.To evaluate our domainindependentagentcontrol,organization,coordinationand architecturalschemes,we continueto refineour understandingof the current applicationsand are activeIy pursuingnewapplicationsto testour system.Thereferences below andthe web pagehttg:/~~.~~~.cs.cPlu.edul’softag~ts providefurtherdetails. References [l] K. Decker,K. Sycam,and M. Williamson. Middleagentsfor the internet. In Proceeding of IJCAI-97, Nagoya,Japan,1997.To appear. [2] K. Decker,M. Williamson,and K. Sycara.Matchmaking andbrokering. In Proceedings ofthe Second International Conference on Multiagent Systems, 1996. [3] K. Sycara,K. Decker,A. Pannu,and M. Williamson. Designingbehaviorsfor informationagents.In Proceeding ofAgents-97, pages404-412,Los Angeles,1997. [4] K. Sycam,K. Decker,A. Pannu,M. Williamson,and D. Zeng. Distributedintelligentagents. IEEE Expert, pages36-46, December1996.
