9/10/98USC-ISI / ASTT IPR1 Flexible Group Behavior Randall Hill, USC-ISI Jonathan Gratch, USC-ISI...

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Transcript of 9/10/98USC-ISI / ASTT IPR1 Flexible Group Behavior Randall Hill, USC-ISI Jonathan Gratch, USC-ISI...

  • Flexible Group BehaviorRandall Hill, USC-ISIJonathan Gratch, USC-ISIASTT Interim Progress ReviewSeptember 10, 1998

    USC-ISI / ASTT IPR

  • HypothesesThe key to flexible behavior is handling situation interruptsUnderstand the nature of the situation and adjust behavior appropriatelyAchieve goals in spite of unexpected obstaclesFlexible group behavior requires the ability to:Understand behavior of groups of other agentsMaintain situation awareness of friendly and adversarial groupsRecognize when a situation does not match expectationsPlan a mission for groups against groupsCollaborate with peers and superiorsPerform adversarial reasoningExecute mission plan in a coordinated mannerReact to situation interrupts, as a teamRepair plans, when necessary, and continue executing mission

    USC-ISI / ASTT IPR

  • Hypotheses (2)Flexible group behavior interleaves the processes of situation awareness, planning, and executionRequires concurrent, continuous integration of each processSpans individuals, groups, and echelonsAffects how plans are generated and repaired Need methods for integrating the component processesGroup behavior requires a theory of multi-agent interactionProvides a framework for understanding others behaviorAddresses issues of authority & autonomyEnables collaborative & adversarial reasoningProvides protocol for coordination and communication

    USC-ISI / ASTT IPR

  • Towards Flexible Group BehaviorBattalionCompanyEntity

    USC-ISI / ASTT IPR

  • State of the ArtCurrent research on flexible group behavior is fragmentedGroup Understanding & ExecutionTeamwork modelDeveloped for RWA-Soar and participated in STOW-97 ACTDAttack Helicopter Company + Command entityMarine transport / Marine escort teamsExecutes plans with reactive behaviorUnderstands own teams roles, activities, and goalsProvides coordination and communication protocol during executionLimitations of teamwork modelDoes not understand other groups behaviorDoes not perform deliberative planningDoes not reason about task dependencies when resolving conflicts

    USC-ISI / ASTT IPR

  • State of the ArtAI planning systemsHierarchical task network / partial order planners (IPEM,X11,DPLAN)Generate, execute, repair plansExample: Soar-CFOR RWA company command entityNot designed for multi-agent, collaborative planningMulti-agent planningJoint Intentions / Shared Plans (Cohen & Levesque; Grosz & Kraus)Focuses on collaboration and reasoning about intentionsLacks situation awareness, execution, repair, authority, adversarial planning.Generalized Partial Global Planner (Lesser & Decker)Focuses on coordination strategies and collaborative schedulingLacks notion of authority, adversarial planning

    USC-ISI / ASTT IPR

  • ApproachBuild on Soar-CFOR model of planning, execution & repairNeed more flexibility in responding to situation interruptsNeed to extend model to higher echelonsDevelop more situation awarenessDetailed awareness of commanders intentDetailed awareness of other friendly activitiesDetailed awareness of enemy situationConstant tracking and updates of friendly and adversarial forces

    USC-ISI / ASTT IPR

  • Approach (2)Develop a more flexible approach to planningTake advantage of enhanced situation awarenessEnable multi-agent reasoningCollaborationAuthorityAdversarial reasoningImplement as a meta-reasoning capability on top of standard plannerDont re-invent technologyUses a standard planning paradigmBuilds on existing systems (RWA-Soar and Soar-CFOR)The meta-reasoning layer integrates fragments of related research

    USC-ISI / ASTT IPR

  • Technology and R&DArchitectureSituation AwarenessPlanningSituation Interrupts and PlanningMulti-agent Planning

    USC-ISI / ASTT IPR

  • System ArchitectureBattalion CommanderCompany ACommanderCompany XCommanderCompany APilotHelicopterPilotHelicopterPilotHelicopterModSAFCompany XPilotHelicopterPilotHelicopterPilotHelicopter..Operations Order(plan)Operations Order(plan)Operations Order(plan)Situation Report(understanding)Situation Report(understanding)Situation Report(understanding)PerceptsActionsPerceptsActions

    USC-ISI / ASTT IPR

  • Command Agent ArchitectureUnderstandingPerceive and report groups of enemy entitiesUnderstand plans from superiors/subordinatesMonitor execution of plans by subordinatesPlanningGenerate plans (collaboratively) at battalion and company levelsBattalion commander resolves conflicts in company plansExecutionBattalion executes plansRepair plans when situation interrupt occurs

    USC-ISI / ASTT IPR

  • Command Agent ArchitecturePlansEnvironmentCurrent SituationDomainTheoryPlannerSituation AwarenessRadio VisionRadio Platform CommandsExpectations

    USC-ISI / ASTT IPR

  • Situation AwarenessHide information gathering details from PlannerDerives consolidated picture of current situation from:Radio reports (via 16 CCSIL message types)OpOrders, SitReps, Status Reps, Replacement Reqs, Flight Advisory, BDA, Request Passage Coordination, etc...Vehicle Sensors (via MITRE CFOR platform services)Expectationsexpected enemy contact (derived from OpOrder)frequency of subordinate Status RepsRule-based reasoningCan perform limited sensing actionse.g.. Request situation reports

    USC-ISI / ASTT IPR

  • Situation Awareness OutputList of facts currently true in the world16B11 at holding_area ha1116B14 presumed deadEnemy ADA platoon threatening battle_position bp141Target in EA nelson has been attrittedIve communicated order76 to 16C11Ive received new orders from my commanderFacts are echelon and unit type specificBattalion tracks different information than companyCSS unit tracks different information than RWA unit Determined by domain theory

    USC-ISI / ASTT IPR

  • Planner

    Implements basic command and control functionsGenerates plansControls execution and coordination of subordinatesRecognizes Situation Interrupts and makes repairsGIVEN: Domain theory (tasks, plan fragments, assets)Mission objectives, friendly/enemy plans (from OPORDER)Existing plansCurrent situation (from Situation Awareness)

    USC-ISI / ASTT IPR

  • What are Plans?Plans are partially ordered sequences of tasksPlans capture assumptionsColumn movement assumes enemy contact unlikelyPlans capture dependencies between task Move_to_Holding_Area results in unit being at the HA, which is a precondition to moving to the Battle_PositionEnemy and Company must be at the Engagement_area at the same timeDifferent plans associated with different groupsBattalion plan, company plan, enemy plans

    USC-ISI / ASTT IPR

  • Planning BasicsPlan generationSketch basic structure via decompositionFill in details with causal-link planningPlan executionExplicitly initiate and terminate tasksInitiate tasks whose preconditions unify with the current world Terminate tasks whose effects unify with the current world

    USC-ISI / ASTT IPR

  • Example of Plan GenerationDestroyed(Enemy)Attack(A, Enemy)Move(A,BP)Engage(A,Enemy)at(A,BP)at(A,FARP)at(Enemy,EA)at(A,BP)Destroyed(Enemy)Destroyed(Enemy)at(A,FARP)at(Enemy,EA)Current World. . .init

    USC-ISI / ASTT IPR

  • Situation Interrupts Happen!What if the world changes unexpectedly?Agents exist for extended time periodsPlans and goals may change over timeActions have duration and may failEnvironment may change unexpectedlyOther agent may take unanticipated actionTo the planner this meansEffect of an action in the plan is deleted even though no task deletes itEffect of an action is added even though no task adds itNeed method for handling situation interrupts

    USC-ISI / ASTT IPR

  • Exampledestroyed(Enemy)Attack(A, Enemy)Move(A,BP)Engage(A,Enemy)at(A,BP)at(A,FARP)at(A,BP)destroyed(Enemy)destroyed(Enemy)at(A,FARP)at(Enemy,EA)Current Worldactive(A).initUnexpected Event-active(A)active(A)active(A)

    USC-ISI / ASTT IPR

  • Reacting to Situation InterruptSituation interrupt may force retraction of plan decisionsExample:Bn commander generates plan sending Company A to engage enemy tanksCompany A is destroyed on way to the battle position Movement tasks of Company A are now invalid and must be retracted.Plan dependencies capture the ramifications of interruptsRepair plans in response to ramificationsRetract stepsAdd new stepsAdd additional constraints

    USC-ISI / ASTT IPR

  • Multi-Agent PlanningWant to plan in context of other agentsWant to explicitly reason about their plans Want to plan in a socially appropriate mannerTreat my friends with respect (collaborate or avoid negative interactions)Treat my enemies with contemptUnderstand what I am required to doUnderstand where I have discretion to make decisionUnderstand who I have authority to command

    USC-ISI / ASTT IPR

  • Multi-Agent PlanningMust represent goals and activities of other agentsMust reason about interactions / conflicts across agentsCannot treat all plans equallyMust understand your relationship to other agents during planningModulate behavior of planner based on these relationships

    USC-ISI / ASTT IPR

  • Interaction ExampleMove(A,BP)Engage(A,Y)Dead(Y)Move(CSS,HQ)at(CSS,HQ)at(CSS,FAA)at(gas,FAA)at(gas,HQ)at(A,BP)at(A,FAA)at(A,BP)at(gas,FAA)Initial StateCombat Service Support PlanAttack Helicopter Company Planresupplied(HQ)

    USC-ISI / ASTT IPR

  • Planning StancesAuthoritative: modify/generate other agents plans Tell CSS to abandon re-supply operationSubordinate: use others plan to defer to their actionsFind a way to work around re-supply activitydo I have time to do the engagement first?Collaborative: use others plan to reach mutual solution Consult to see if some other resource could achieve the resupplyAdversarial: use others plan against t