A Proposal for a Layered Architecture for a Hybrid Object-Based Representation System

In this position paper, we present a proposal for a layered architecture for a hybrid object-based representation system, relying on two kinds of representation formalisms, namely description logics and frame knowledge representation systems or framebased systems I. In description logics, concepts, roles and individuals represent real-world concepts, their properties and their instances. The subsumption relation is used to organize concepts and roles in hierarchies. The subsumption relation is the basis of the two main reasoning mechanisms, classification and instantiation. By contrast, in a frame-based system, real-world knowledge is represented by frames -or classesand instances. A frame has an identity, a state and a behavior, and it is used to generate a set of instances. Frames are organized in a hierarchy relying on the specialization relation, where the inheritance mechanism is used for information retrieval and for default reasoning. Moreover, the behavior of frames, i.e. methods, can be activated by message passing. The layered architecture described in the following is a first practical framework for integrating multiple representation and programming formalisms, namely constructions and knowledge units of frame-based systems and description logics. This architecture has been inspired by knowledge repre-