My PhD Thesis

Front cover
    Title: Using Multiple Models of Reality. On Agents who Know how to Play Safer.
    Author: Wojciech Jamroga, Parlevink Group, University of Twente.
    The "wise men committee": Anton Nijholt (promotor), Wiebe van der Hoek (co-promotor), Job Zwiers (assistant promotor) and Mannes Poel.

    Thesis defended on the 1st of July 2004 at the University of Twente in Enschede, the Netherlands.

    The defense committee: Job van Amerongen (chairman, University of Twente), Marek Bednarczyk (Polish Academy of Science), Ed Brinksma (University of Twente), Anton Nijholt (University of Twente), Valentin Goranko (Rand Afrikaans University), Wiebe van der Hoek (University of Liverpool), Theo Huibers (University of Twente), John-Jules Meyer (Utrecht University), Job Zwiers (University of Twente).

Abstract: This thesis considers some aspects of multi-agent systems, seen as a metaphor for reasoning about the world, and providing a conceptual machinery that can be used to model and analyze the reality in which an agent is embedded. First, we study several modal logics for multi-agent systems; in particular, Alternating-time Temporal Logic (ATL) is studied in various contexts. Then, a concept of multi-level modeling of reality and multi-level decision making is proposed in the second part of the thesis.

The formal investigation of ATL yields equivalence results for several different semantics of this language, as well as a thorough comparison of ATL and Coalition Logic -- another recent logic of strategic ability. We also study an epistemic extension of ATL, show a satisfiability preserving interpretation of the extension into the ``pure'' ATL, and demonstrate its similarities to the well known BDI logic of beliefs, desires and intentions. After that, we point out some counterintuitive features of this particular extension, and propose how it can be recovered. The extension can be also seen as a generic scheme of enriching game theory-based logics with other concepts and dimensions. To support this, we propose how ATL can be extended with the deontic notion of obligation. Apart of investigating cooperation modalities and their semantics as the formal counterpart of the decision making process, we devise efficient procedures for multi-agent planning to achieve goals that can be expressed with formulae of \lan{ATL} and some of its extensions.

In the second part of the thesis, a concept of multi-level modeling of reality is proposed, where various models of the same environment can be combined to improve decision making. Our main motivation is to endow agents with some way of using secure game theory-based models together with adaptive models obtained through machine learning. We try several confidence measures, and verify the whole idea through experiments with simple software agents in an e-banking scenario.


The whole thesis can be downloaded here (PDF file, 1.8M).

You can also have a look at my slides from the "general public introduction" I gave before my defense (Power Point presentation, 700K).

There is a bunch of photos from the defense, courtesy of Maciek Zwierzycki, who turned them into a hilarious reportage from the event. The reportage is available here.

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Computational Intelligence Group @ Clausthal University of Technology Last modified 2010-03-17