Multi-Agent Systems Lecture IV
• Dr. Nestor Velasco Bermeo,
• Researcher CONSUS (Crop OptimisatioN through
Sensing, Understanding & viSualisation), • School of Computer Science
• University College Dublin (UCD)
Beliefs, Desires and Intentions
• Let us consider these three mental attitudes:
• Beliefs • Desires • Intents
•Beliefs: represent environment characteristics, which are updated accordingly after the perception of each action.
Beliefs, Desires and Intentions
•Desires: Store information of; goals, properties and costs associated.
•Intentions: current action plan chosen. Captures the deliberative component of the system.
Practical Reasoning in a BDI agent
Practical reasoning in a BDI agent
•Belief revision function; takes a perceptual input and the agent’s current beliefs, and on the basis of these, determines a new set of beliefs;
•Beliefs (current); represent information about its current environment;
•Option Generation Function; determines available options, on the basis of its current beliefs about its environment and its current intentions.
Practical reasoning in a BDI agent
•Filter; (function) agent’s deliberation process, determines intentions based on the current BDIs;
•Set of current options; representing possible courses of actions.
•Intentions (Set); agent’s current focus
•Action selection function; determines an action to perform on the basis of current intentions.
Early Multi-Agent Environments
❑ ABE (Erman et al 1988)
❑ ARCHON (Wittig 1989)
❑ CooperA (Sommaruga et al 1989) ❑ MACE (Gasser et al 1987)
❑ MADE (Wooldridge & O’Hare 1990) ❑ Agent Factory (O’Hare 1992)
❑ MCS (Doran et al 1991)
❑ GBB (Hayes-Roth et al 1988)
Classes of Commitment Strategies
• Several degrees of commitment may be exhibited by agents.
• Rao and Georgeff identified three discrete points on this commitment continuum:
❑ Blind Commitment
❑ Single-Minded Commitment ❑ Open-Minded Commitment
Blind Commitment
Blind commitment is defined as the adherence to a commitment until such time as the agent believes it has achieved the commitment.
Single-Minded Commitment
• Single-minded commitment represents a relaxation of blind commitment in that the agent will not drop its commitments unless it believes that they are no longer achievable.
• The computational overhead of ascertaining whether a given goal is achievable can be considerable.
• Rao and Georgeff suggest that this can be achieved by permitting belief revision but not goal revision.
Open-Minded Commitment
•Open-minded commitment offers a further relaxation in that an agent is willing to revise its goals and beliefs, retaining commitments that are still compatible with its goals.
Coordination through Communication…
• Coordination represents the problem or activity of reconciling the actions of the individual agent with those of the group or indeed organisation.
• Since agents actions are derived from their goals and since agents are frequently benevolant there will inevitably be conflict.
• Such interference can only be reconciled through communication.