Collectively Cognitive Agents in Cooperative Teams Jacek Brzeziński, Piotr Dunin-Kęplicz Institute...
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Transcript of Collectively Cognitive Agents in Cooperative Teams Jacek Brzeziński, Piotr Dunin-Kęplicz Institute...
Collectively Cognitive Agents Collectively Cognitive Agents in Cooperative Teamsin Cooperative Teams
Jacek Brzeziński, Piotr Dunin-KępliczInstitute of Computer Science, Polish Academy of Sciences
Barbara Dunin-KępliczInstitute of Computer Science, Polish Academy of Sciences
Institute of Informatics, Warsaw University
GoalsGoals
Simulator– Collective Commitment Theory (B. Dunin-Kęplicz, Verbrugge)
– Theory of Trust (Castelfranchi, Falcone)
Research of some BDI systems propertieswhen different definitions of collective commitments are used:– are agents willing to cooperate?– does the system evolve? – quality of teamwork?– how much information is needed for agents to
cooperate productively?– how to calculate the degree of trust?
OverviewOverview
Collective Commitments theorySimulator:– agents– interaction scenario– different CC models w.r.t. trust
Test resultsFuture work
Collective commitmentsCollective commitments
Tuning machine allows to select collective commitment type w.r.t.:– group awareness about social plan– group awareness about distribution of
bilateral commitments– existence of collective intention
Different models of organizations
Examples of collective commitmentExamples of collective commitment
Robust collective commitment
Weak collective commitment
Distributed commitment
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Roles of agentsRoles of agents
Managers– generate tasks (sets of actions) to be
performed by Workers for a specific salary– do not execute actions– delegate actions (or sets of actions) to other
agents (Workers)
Workers– perform actions– cannot delegate actions
Properties of agentsProperties of agents
Beliefs– believes(A, f) - agent A believes f
Intentions– intends(A, a) - agent A intends to perform action a
Abilities– able(A, a, n) - agent A is able to perform action a
(n - probability of success)
Trust– trusts(A, B, a, n) - agent A trusts in agent B to do a in degree of n
– trust values base on direct experience.
– Workers & Manager trust in Workers to execute specific actions.
– Workers trust in Manager to do proper team selection.
Four levels of CPSFour levels of CPSManager has a task (set of actions) to perform:1. Potential recognition
Manager recognizes potential for cooperative action in order to complete the task
2. Team formationManager attempts to establish group of agents that can collectively fulfil the goal (collective intention)
3. Plan generationSocial plan of achieving the goal is built and the collective commitment is formed
4. Team actionAgents involved do their tasks and eventually achieve the main goal
Potential recognitionPotential recognition
M sends CFP to all the Workers in the system (content = (O - set of actions))
Workers respond with their bids M chooses the best group G that can
perform the task collectively w.r.t.:– trust in Workers in the group– prices proposed by Workers – risk factor describing preferences of M
Team formation & plan generation 1Team formation & plan generation 1
M broadcasts relevant information to all Workers in G:– an offer to form a group– an offer to participate in task– an allocation of actions– division of task O into subtasks– an offer to perform action(s) for price x
Team formation & plan generation 2Team formation & plan generation 2
Agents decide whether to join the group Task result estimation function takes into account following factors:• trust in the manager M• trust in other members of the group• ability to perform delegated actions
If all Workers agree, then collective commitment is constructed.
Team actionTeam action
Workers perform actions and tell M about results
If all actions have succeeded, the task also succeeds and all Workers collect their payments
Results of actions are propagated to group members, depending on team awareness level
Agents modify their degrees of trust in other group members (basing on direct experience)
Robust collective commitmentRobust collective commitment
Information sent to Workers– an offer to create a group G with intention to realize
task O– an allocation of sets of actions– an offer to perform a set of actions for a price of x
Task result estimation function
Result propagation– All the information about successes and failures
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Weak collective commitmentWeak collective commitment
Information sent to Workers– an offer to create a group G with intention to realize
task O– a division of task O into subtasks S– an offer to perform a set of actions for a price of x
Task result estimation function
Result propagation– only failure information: agent, failed action, subset of O
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Distributed commitmentDistributed commitment
Information sent to Workers– an offer to perform a set of actions for a price
of x Task result estimation function
Result propagation– only the team action result
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TestsTests
Configuration• 16 Workers, 1 Manager• 100,000 tasks• 4 actions in every task• abilities set randomly between 0.5 and 1• starting trust value = 1
Parameters• number of successful/failed contracts• efficiency• difference between trust values and real abilities
Test ResultsTest Results
Strong models of CC:– efficient–moderate number of contracts– agents learning from experience– costly (comm. resources)
Weak models– unstable–many contracts, mostly failing
Robust Collective CommitmentRobust Collective Commitment
Distributed CommitmentDistributed Commitment
Future workFuture work
Complex organization model– more managers– more detailed trust model– more complex commitment structure– institutional restrictions
Reconfiguration– role of trust
Dynamic commitment model evolution