Goal generation with relevant and trusted beliefs

ABSTRACT

A rational agent adopts (or changes) its goals when new information (beliefs) becomes available or its desires (e.g., tasks it is supposed to carry out) change. In conventional approaches to goal generation in which a goal is considered as a "particular" desire, a goal is adopted if and only if all conditions leading to its generation are satisfied. It is then supposed that all beliefs are equally relevant and their sources completely trusted.

However, that is not a realistic setting. In fact, depending on the agent's trust in the source of a piece of information, an agent may decide how strongly it takes into consideration such piece of information in goal generation. On the other hand, not all beliefs are equally relevant to the adoption of a given goal, and a given belief may not be equally relevant to the adoption of different goals.

We propose an approach which takes into account both the relevance of beliefs and the trust degree of the source from which the corresponding piece of information comes, in desire/goal generation. Two algorithms for updating the mental state of an agent in this new setting and three ways for comparing the resulting fuzzy set of desires have been given. Finally, two fundamental postulates any rational goal election function should obey have been stated.

REFERENCES

• 1: C. E. Alchourrón, P. Gärdenfors, and D. Makinson. On the logic of theory change: Partial meet contraction and revision functions. J. Symb. Log., 50(2):510--530, 1985.
• 2: John Bell , Zhisheng Huang, Dynamic Goal Hierarchies, Proceedings from the Workshop on Intelligent Agent Systems, Theoretical and Practical Issues, p.88-103, August 26-30, 1996
• 3: J. Broersen, M. Dastani, J. Hulstijn, and L. van der Torre. Goal generation in the BOID architecture. Cognitive Science Quarterly Journal, 2(3--4):428--447, 2002.
• 4: Cristiano Castelfranchi , Rino Falcone , Giovanni Pezzulo, Trust in information sources as a source for trust: a fuzzy approach, Proceedings of the second international joint conference on Autonomous agents and multiagent systems, July 14-18, 2003, Melbourne, Australia [doi>10.1145/860575.860590]
• 5: Philip R. Cohen , Hector J. Levesque, Intention is choice with commitment, Artificial Intelligence, v.42 n.2-3, p.213-261, March 1990 [doi>10.1016/0004-3702(90)90055-5]
• 6: C. da Costa Pereira, F. Garcia, J. Lang, and R. Martin-Clouaire. Planning with graded nondeterministic actions: a possibilistic approach. International Journal of Intelligent Systems, 12:935--962, 1997.
• 7: C. da Costa Pereira and A. Tettamanzi. Towards a framework for goal revision. In Proceedings of BNAIC'06, pages 99--106, 2006.
• 8: F. Dignum, D. N. Kinny, and E. A. Sonenberg. From desires, obligations and norms to goals. Cognitive Science Quarterly., 2(3--4):407--427, 2002.
• 9: D. Dubois and H. Prade. Possibility theory as a basis for qualitative decision theory. In Proceedings of IJCAI'95, pages 19--25, 1995.
• 10: Rino Falcone , Cristiano Castelfranchi, Social trust: a cognitive approach, Trust and deception in virtual societies, Kluwer Academic Publishers, Norwell, MA, 2001
• 11: Rino Falcone , Cristiano Castelfranchi, Trust Dynamics: How Trust Is Influenced by Direct Experiences and by Trust Itself, Proceedings of the Third International Joint Conference on Autonomous Agents and Multiagent Systems, p.740-747, July 19-23, 2004, New York, New York [doi>10.1109/AAMAS.2004.286]
• 12: Felipe Rech Meneguzzi , Avelino Francisco Zorzo , Michael da Costa Móra, Propositional planning in BDI agents, Proceedings of the 2004 ACM symposium on Applied computing, March 14-17, 2004, Nicosia, Cyprus [doi>10.1145/967900.967916]
• 13: J. V. Neumann and O. Morgenstern. Theory of Games and Economic Behavior. Princeton University Press, 1944.
• 14: Iyad Rahwan , Leila Amgoud, An argumentation based approach for practical reasoning, Proceedings of the fifth international joint conference on Autonomous agents and multiagent systems, May 08-12, 2006, Hakodate, Japan [doi>10.1145/1160633.1160696]
• 15: S. Shapiro, Y. Lespérance, and H. J. Levesque. Goal change. In Proceedings of IJCAI'05, pages 582--588, 2005.
• 16: John Thangarajah , Lin Padgham , James Harland, Representation and reasoning for goals in BDI agents, Proceedings of the twenty-fifth Australasian conference on Computer science, p.259-265, January 01, 2002, Melbourne, Victoria, Australia
• 17: R. H. Thomason. Desires and defaults: A framework for planning with inferred goals. In Proceedings of KR'00, pages 702--713, 2000.
• 18: M. B. van Riemsdijk. Cognitive Agent Programming: A Semantic Approach. PhD thesis, University of Utrecht, 2006.
• 19: R. Witte. Fuzzy belief revision. In Proceedings of NMR'02, pages 311--320, 2002.
• 20: R. Yager. An approach to ordinal decision making. International Journal of Approximate Reasoning, 12:237--261, 1995.
• 21: L. A. Zadeh. Fuzzy sets. Information and Control, 8:338--353, 1965.
• 22: L. A. Zadeh, Fuzzy sets as a basis for a theory of possibility, Fuzzy Sets and Systems, v.100 n.supp., p.9-34, 1999

INDEX TERMS

Primary Classification:
  I. Computing Methodologies
  I.2 ARTIFICIAL INTELLIGENCE
      I.2.3 Deduction and Theorem Proving
          Subjects: Nonmonotonic reasoning and belief revision

General Terms:
Theory

Keywords:
beliefs and desires, fuzzy logic, goal generation