designing agent societies

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Designing Agent Societies. Volha Bryl PhD student ICT, DIT [email protected] … …. … …. … …. … …. Agent Society. + collaboration (through delegation). - competitive goals. Agent. Goals Capabilities. - PowerPoint PPT Presentation


  • Designing Agent SocietiesVolha BrylPhD studentICT, [email protected]

  • Agent SocietyAgentGoals Capabilities+ collaboration (through delegation)- competitive goalsSociety members objective: use others capabilities to achieve personal goals

  • Problem

    Find optimal assignments:

    satisfy all goals of all agentsorreach an compromise?

  • Formalization (1)Two types: Actors and Goals

    Goals: an actor wants a goal to be satisfied

    Capabilities: an actor can satisfy a goal

    Communication: an actor can pass (or delegate) a goal to another actor

  • Formalization (2)Goals can be decomposed into subgoals

    Only one possible decomposition

    Goal is satisfied iff all its subgoals are satisfied

    Decomposition can be performed by any actor

    Decomposition is actor-independent

  • Formalization (3)Three basic actions:an actor satisfies a goalan actor passes (or delegates) a goal to another actoran actor decomposes a goal into subgoals

    Solution is a list of actions that should be executed to satisfy all initial goals of all actors (or to reach an equilibrium)

  • IdeaLets look at


    which is in AI the problem of finding a sequence of primitive actions to achieve some goal

  • Planning problemwe need to formalize actions

    an action has precondition and effect

    precondition and effect can be represented as conjunction or disjunction (for precondition only) of predicates or their negations

  • Planning problem. PredicatesActors capabilitiescan_satisfy (a actor, g goal)can_depend_on (a1 actor, a2 actor)Actors initial desireswants (a actor, g goal)Possible decomposition of goalscan_be_decomposed (g goal, g1 goal, g2 goal, )

  • Planning problem. Actions1) Satisfies (a actor, g goal)precondition (and can_satisfy (a, g) wants (a, g) ) effect (and done (g)* not (wants(a,g) )

    * done (g goal) is an additional predicate which means goal g is satisfied, no one wants it anymore

  • Planning problem. Actions2) Decomposes* (a actor, g goal, g1 goal, g2 goal)precondition (and can_be_decomposed (g, g1, g2) wants (a, g) ) effect (and wants(a,g1) wants(a,g2) not (wants(a,g) )

    * can be extended to more than two actions

  • Planning problem. Actions3) Passes (a1 actor, g goal, a1 actor)precondition (and can_depend_on (a1, a2) wants (a1, g) ) effect (and wants(a2, g) not (wants(a1, g) )

  • Planning problem. Intuition (1)wants (A, G)Decomposes (A, G, G1, G2)wants (A, G1)wants (A, G2)wants are propagated through the graph and then eliminated become done

  • Planning problem. Intuition (2)wants (A, G)done (G)Satisfies (A, G)wants are propagated through the graph and then eliminated become donewants (A, G)wants (B, G)Passes (G, A, B)

  • Example. Informal formulationI can buy a ticketI want to go to the conferenceto go there means: buy a ticket and get reimbursementProfessorAccounting officeI can ask accounting office for helpWe can help to get the reimbursement

  • Example. PDDL formulation(define (problem example) (:domain tropos-domain) (:objects Professor Accounting_office - t_actor Go_to_conference Get_reimbursement Buy_ticket - t_goal ) (:goal (and (done Go_to_conference) ) ) (:init (can_do Accounting_office Get_reimbursement ) (can_do Professor Buy_ticket ) (can_depend_on Professor Accounting_office ) (wants Professor Go_to_conference ) (and_subgoal2 Go_to_conference Buy_ticket Get_reimbursement ) )

  • Example. Using the tool

  • Example. Using the tool

  • Example. Solutiondecomposes [professor, go-to-conference, buy-ticket, get-reimbursement] performs [professor, buy-ticket]pass [professor, get-reimbursement, accounting-office]performs [accounting-office, get-reimbursement]

  • Big example. DescriptionI need to write a letter to the UK embassyI know EnglishI can use printerI have an official stampI can only sign lettersBoss1st Secretary2nd Secretary3rd Secretaryto write a letter means: type, print and certify it with stamp and bosss signature

  • Big example. Solutiondecomposes [boss, write-letter, send-letter, type-letter-in-english] decomposes [boss, send-letter, certify-letter, print-letter] pass [boss, type-letter-in-english, secretary-1] pass [boss, print-letter, secretary-1] performs [secretary-1, type-letter-in-english] decomposes [boss, certify-letter, stamp-letter, sign-letter] pass [boss, stamp-letter, secretary-1] performs [boss, sign-letter] pass [secretary-1, print-letter, secretary-2] performs [secretary-2, print-letter] pass [secretary-1, stamp-letter, secretary-2] pass [secretary-2, stamp-letter, secretary-3] performs [secretary-3, stamp-letter] combines [certify-letter, stamp-letter, sign-letter] combines [send-letter, certify-letter, print-letter] combines [write-letter, send-letter, type-letter-in-english]

  • Big example. Solution

  • Summing up two views

    We have different views on the problemCooperation in multi-agent communities (strategic games)Analyzing requirements

    These views might be though as different application areas of the proposed solution

  • Summing up or what we do not haveWe need iterative solution building (iteration by imposing constraints on next solution)

    We need partial solution (compromise or equilibrium) and its evaluation

    We need the possibility of introducing new actors during the solution building