Knowledge representation models based on conceptual graphs in intelligent educational systems

Intelligent educational systems are knowledge-based systems (KBS) they can be developed by a generic knowledge-based system development methodology. The KBS development is essentially a modeling activity, that yields a series of models at different levels of abstraction. Explicit representation of domain knowledge (in the subject being taught) and pedagogical knowledge (how to teach this material) are the two most intensive and complex tasks in building an educational system. In this paper, we present an ontology-based approach for formalising different knowledge types. The formalism is based upon conceptual graphs. Conceptual graphs (CG), with their formal structures and operations, appear to be a suitable formalism for constructing domain ontology and pedagogical ontology and for reasoning. For implementation, we use the CoGITaNT environment (Conceptual Graphs Integrated Tools allowing Nested Typed graphs), a library of C++ classes (open-sources, developed by LIRMM CNRS, France) allowing the development of applications based on the CG knowledge representation scheme.