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Description

In a recent paper [1] we provided the theoretical foundation for the realization of a knowledge-based system based on the logic ES [2,3], a modal variant of the Situation Calculus [4,5]. The main advantages over existing approaches [6] is that it allows a more powerful query language, including nested belief operators and quantifying-in, and does not have to rely on meta-theoretic mechanisms to represent the agent's lack of knowledge.

The goal of this thesis is to implement and practically evaluate these results. For that purpose, an existing agent framework [7] based on the action language IndiGolog [8,9,10] is to be extended appropriately. Queries (i.e. test conditions) need to be first transformed as described in [1] and then checked against the agent's knowledge base. To avoid the loss in expressiveness that comes with the often used technique of propositionalization (e.g. [6]), the latter is to be done using a full FOL theorem prover (such as Vampire, Otter or Paradox, see also [11]) that needs to be embedded accordingly in IndiGolog. In the evaluation, the new system's performance and practicality is to be compared to the original IndiGolog in the context of the Wumpus domain [12]. Additionally, a new example domain (e.g. an extension of the Wumpus world) is to be created.

Requirements

• lecture "Introduction to Artifical Intelligence"
• lecture "Introduction to Knowledge Representation" (strongly recommended)
• lecture "The Logic of Knowledge Bases" (recommended)
• skills in Prolog programming (plus a bit Java and Linux Shell)

References

[1] Claßen, Jens; Lakemeyer, Gerhard. Foundations for Knowledge-Based Programs using ES. 10th Conf. on Principles of Knowledge Representation and Reasoning (KR2006), (2006) [PDF]

[2] Lakemeyer, Gerhard; Levesque, Hector. Situations, si! Situation Terms, no! 9th Conf. on Principles of Knowledge Representation and Reasoning (KR2004), (2004) [PDF]

[3] Lakemeyer, Gerhard; Levesque, Hector. Semantics for a useful fragment of the situation calculus. Proc. IJCAI-05, (2005) [PDF]

[4] Hector J. Levesque, Fiora Pirri, Raymond Reiter: Foundations for the Situation Calculus. Electron. Trans. Artif. Intell. 2: 159-178 (1998) [PS]

[5] Pirri, F., and Reiter, R. Some Contributions to the Metatheory of the Situation Calculus. 1999.
Journal of the ACM, 46(3):261--325. [PDF]

[6] Reiter, R. On Knowledge-Based Programming with Sensing in the Situation Calculus. 2001. ACM Transactions on Computational Logic (TOCL), 2(4):433--457, October. [PDF]

[7] The IndiGolog Framework [Link], [Link]

[8] Levesque, H, Reiter R., Lesperance, Y., Lin F., and Scherl R. GOLOG: A logic programming language for dynamic domains. Journal of Logic Programming, 31, 1997, 59-84. [PDF]

[9] De Giacomo, G.; Lespérance, Y.; and Levesque, H. ConGolog, A Concurrent Programming Language Based on the Situation Calculus. 2000. Artificial Intelligence, 121(1--2):109--169. [PDF]

[10] Sebastian Sardiña, Giuseppe De Giacomo, Yves Lespérance, Hector J. Levesque: On the Semantics of Deliberation in Indigolog - from Theory to Implementation. Ann. Math. Artif. Intell. 41(2-4): 259-299 (2004)

[11] CASC Competition [Link]

[12] Sebastian Sardina and Stavros Vassos. The Wumpus World in IndiGolog: A Preliminary Report. Proceedings of the Nonmonotonic Reasoning, Action and Change Workshop at IJCAI (NRAC-05), pages 90-95, Edinburgh, Scotland, 2005. [PDF]

Contact

Jens Claßen