IT & Engineering

Recently there has been considerable interest in change operators for theory bases, rather than entire theories. Especially since such operators could support computer-based implementations of revision systems. However, a perceived problem associated with theory base change operators is their sensitivity to the syntax of the theory base used. Although it has been argued that this sensitivity should reflect a higher level of commitment to formulae in the theory base than formulae derivable from the theory base. In this paper we develop a logic of theory base change, using constructions based on ensconcements. We show whenever two theory bases have equivalent ensconcements, the logical closure of their theory base revisions are identical. Moreover, we give explicit relationships associating theory base revision and theory base contraction, and provide explicit relationships between theory base change and theory change operations. We claim that these relationships show that our theory base revision and theory base contraction operators exhibit desirable behaviour.

Belief Revision is a ubiquitous process under-lying many forms of intelligent behaviour. The AGM paradigm is a powerful framework for modeling and implementing belief revision sys-tems based on the principle of Minimal Change; it provides a rich and rigorous foundation for ...

Page 1. Rea soning Grigoris Antoniou Page 2. Page 3. Page 4. 'onmonotonic Reasoning Grigoris Antoniou Nonmonotonic reasoning provides formal methods that enable intelligent systems to operate adequately when faced with incomplete or changing information. ...

The aim of this paper is to describe the algorithmic foundations of the part of the program Exten responsible for the computation of extensions in Constrained Default Logic. Exten is a system that computes extensions for various default logics. The efficiency of the system is increased by pruning techniques for the search tree. We motivate and present these techniques, and demonstrate that they can cut down the size of the search tree significantly. Quite importantly, they complement well the recently developed stratification method. This technique has to be modified to work properly with Constrained Default Logic, and we show how this can be done. Exten supports experimentation with default logic, allowing the user to set various parameters. Also it has been designed to be open to future enhancements, which are supported by its object-oriented design. Exten is part of our long-term effort to develop an integrated toolkit for intelligent information management based on nonmonotonic reasoning and belief revision methods.

Robots interacting with other agents in dynamic environments require robust knowledge management capabilities if they are to communicate, learn and exhibit intelligent behaviour. Symbol grounding involves creating, and maintaining, the linkages between internal symbols used for decision making with the real world phenomena to which those symbols refer. We implement grounding using ontologies designed for the Semantic Web. We use SONY AIBO robots and the robot soccer domain to illustrate our approach. Ontologies can provide an important bridge between the perceptual level and the symbolic level and in so doing they can be used to ground sensory information. A major advantage of using ontologies to ground sensory and symbolic information is that they enhance interoperability, knowledge sharing, knowledge reuse and communication between agents. Once objects are grounded in ontologies, Semantic Web technologies can be used to access, build, derive, and manage robot knowledge.

Yan Bai, University of Washington, USA Feng Bao, Institute for Infocomm Research, Singapore Ken Barker, University of Calgary, Canada Jianneng Cao, Purdue University, USA Mauro Conti, University of Padua, Italy Bruno Crispo, University of Trento, Italy Dipankar Dasgupta, University of Memphis, USA Boi Faltings, Swiss Federal Institute of Technology, Switzerland Elena Ferrari, University of Insubria, Italy Simone Fischer-Huebner, Karlstad University, Sweden Michael Franz, University of California–Irvine, USA Gabriel Ghinita, University of ...

Robot Soccer involves planning at many levels, and in this paper we develop high level planning strategies for robots playing in the RoboCup Four-Legged League using case based reasoning. We develop a framework for developing and choosing game plays. Game plays are widely used in many team sports e.g. soccer, hockey, polo, and rugby. One of the current challenges for robots playing in the RoboCup Four-Legged League is choosing the right behaviour in any game situation. We argue that a flexible theoretical model for using case based reasoning for game plays will prove useful in robot soccer. Our model supports game play selection in key game situations which should in turn significantly advantage the team.