The talk was based on the following workshop paper I presented at AIIDE-2011: The SimpleFPS Planning Domain: A PDDL Benchmark for Proactive NPCs.

The details of the talk can be found here. The slides of my presentation can be found here.

Abstract:
In this paper we study the progression of situation calculus action theories that are able to handle a class of actions that, while extremely simple conceptually and common in many settings, cannot be handled by previous approaches. Specifically, based on the notion of safe-range queries from database theory and just-in-time action histories, we present a new type of action theories that ensures that actions have bounded effects over a restricted range of objects. Such theories may represent incomplete information and can be progressed by directly updating the knowledge base in an algorithmic manner.

Bibtex:

@inbook{vassos11hectorfest,
author = {Vassos, Stavros and Sardina, Sebastian},
booktitle = {Knowing, Reasoning, and Acting: Essays in Honour of Hector J. Levesque},
editor = {Lakemeyer, Gerhard and McIlraith, Sheila},
publisher = {College Publications},
title = {A Database-type Approach for Progressing Action Theories with Bounded Effects},
year = {2011}
}

Bibtex:

@inproceedings{vassos11simplefps,
author = {Vassos, Stavros and Papakonstantinou, Michail},
booktitle = {AIIDE 2011 Workshop on Non Player Character AI},
location = {Stanford, California, USA},
month = oct,
title = {The {SimpleFPS} Planning Domain: A {PDDL} Benchmark for Proactive {NPCs}},
year = {2011}
}

Bibtex:

@inproceedings{vassos09rangerestricted,
address = {Toronto, Canada},
author = {Vassos, Stavros and Sardina, Stavros and Levesque, Hector},
booktitle = {Proceedings of the Ninth International Symposium on Logical Formalizations of Commonsense Reasoning (CS-09)},
editor = {Lakemeyer, Gerhard and Morgenstern, Leora and Williams, Mary-Anne},
pages = {135–140},
publisher = {UTSePress},
title = {Progressing basic action theories with non-local effect actions},
year = {2009}
}

Bibtex:

@inproceedings{vassos09localeffect,
address = {Sydney, Australia},
author = {Vassos, Stavros and Lakemeyer, Gerhard and Levesque, Hector},
booktitle = {Proceedings of 11th International Conference on Principles of Knowledge Representation and Reasoning (KR-08)},
editor = {Brewka, Gerhard and Lang, J{\’{e}}r{\^{o}}me},
pages = {662–672},
publisher = {AAAI Press},
title = {First-Order Strong Progression for Local-Effect Basic Action Theories},
year = {2009}
}

This paper was selected for the “Outstanding Paper Honorable Mention Award” in the Twenty-Third AAAI Conference on Artificial Intelligence!
Click here for more details about the award.

Abstract:
In a seminal paper, Lin and Reiter introduced a model-theoretic definition for the progression of the initial knowledge base of a basic action theory. This definition comes with a strong negative result, namely that for certain kinds of action theories, first-order logic is not expressive enough to correctly characterize this form of progression, and second-order axioms are necessary. However, Lin and Reiter also considered an alternative definition for progression which is always first-order definable. They conjectured that this alternative definition is incorrect in the sense that the progressed theory is too weak and may sometimes lose information. This conjecture, and the status of first-order definable progression, has remained open since then. In this paper we present two significant results about this alternative definition of progression. First, we prove the Lin and Reiter conjecture by presenting a case where the progressed theory indeed does lose information. Second, we prove that the alternative definition is nonetheless correct for reasoning about a large class of sentences, including some that quantify over situations. In this case the alternative definition is a preferred option due to its simplicity and the fact that it is always first-order.

Bibtex:

@inproceedings{vassos08conjecture,
author = {Vassos, Stavros and Levesque, Hector},
booktitle = {Proceedings of the Twenty-Third AAAI Conference on Artificial Intelligence (AAAI-08)},
location = {Chicago, Illinois, USA},
month = {July},
pages = {1004–1009},
title = {On the Progression of Situation Calculus Basic Action Theories: Resolving a 10-year-old Conjecture},
year = {2008}
}

Dear Stavros and Hector,

On behalf of the Association for the Advancement of Artificial Intelligence and the AAAI-08 Program Committee, we are pleased to inform you that your paper, entitled “On the Progression of Situation Calculus Basic Action Theories: Resolving a 10-year-old Conjecture,” has been selected for Honorable Mention at AAAI-08.

Each year AAAI’s Conference on Artificial Intelligence honors papers that exemplify high standards in technical contribution and exposition. Papers were recommended for this status by members of the Program Committee during the blind review process. The winning papers were selected by the Program Chairs with the help of some members of the Senior Program Committee.

In recognition of your achievement, you and your coauthors will be presented with certificates by the AAAI-08 Program Cochairs, Dieter Fox and Carla Gomes, during their opening remarks on Tuesday, July 15, at 8:30 am. There will also be an announcement of this honor in the front matter of the AAAI-08 Proceedings.
[...]

More on the paper here and more on the award here.

Abstract:

In this paper, we propose a new progression mechanism for a restricted form of incomplete knowledge formulated as a basic action theory in the situation calculus. Specifically, we focus on functional fluents and deal directly with the possible values these fluents may have and how these values are affected by both physical and sensing actions. The method we propose is logically complete and can be calculated efficiently using database techniques under certain reasonable assumptions.

Bibtex:

@inproceedings{vassos07progression,
title = {Progression of Situation Calculus Action Theories with Incomplete Information},
author = {Vassos, Stavros and Levesque, Hector },
booktitle = {Proceedings of the 20th International Joint Conference on Artificial Intelligence},
editor = {Veloso, Manuela M. },
pages = {2024–2029},
address = {Hyderabad, India},
citeulike-article-id = {1923630},
keywords = {ai, progression, reasoning_about_action, situation_calculus},
month = {January},
year = {2007}
}

Abstract:

This paper describes an implementation of the the Wumpus World in IndiGolog with the objective of showing the applicability of this interleaved agent programming language for modeling agent behavior in realistic domains. We briefly go over the IndiGolog architecture, explain how we can reason about the Wumpus World domain, and show how to express agent behavior using high-level agent programs. Finally, we discuss initial empirical results obtained as well as challenging issues to be resolved.

Bibtex:

@inproceedings{sardina05wumpus,
title = {The {W}umpus {W}orld in {I}ndi{G}olog: {A} {P}reliminary {R}eport},
author = {Sardina, Sebastian and Vassos, Stavros },
booktitle = {In Proceedings the Nonmonotonic Reasoning,
Action and Change Workshop at IJCAI (NRAC-05)},
address = {Edinburgh, Scotland},
pages = {90–95},
citeulike-article-id = {381288},
keywords = {agent, ai, cogrobo, games, golog, incomplete_knowledge, logic, reasoning_about_action, situation_calculus, system, wumpus},
year = {2005}
}