Representation of default knowledge in frame-based description language

Abstract

Most of the formalized frame-based description languages employed in KLONEstyle hybrid systems give up expressing default knowledge, instead concentrate on only definitional properties. In this thesis, we enhance the expressive power of a frame-based description language by representing default relations between concepts, and formalize the enhanced language and its extended terminological resoning. It is also shown that this enhancement preserves all of the definitional advantages, and does not cause the reasoning to become intractable. In addition, we investigate how default knowledge can be considered when the enhanced language is integrated with a fact language within hybrid systems.