In this paper a computational model has been presented which express the Activity Theory in terms of a CSCL ontology. This ontology offers a conceptual knowledge level representation for describing collaborative learning systems. It is based upon the structure and the knowledge contained in previous ontologies together with knowledge which was not explicitly represented in other collaborative learning ontologies. This ontology has been designed to be reusable by different tools in many collaborative learning scenarios due to the combination of the theoretical AT framework with an underlying XML-based representation.
One of the theoretical concept of this paper is to use actions as a unit of analysis as the needed structure to make context of a situation explicit. This choice is therefore discussed over a number of other studies which made other decisions privileging more communication models or problem solving methods or learning goals. The structure of these ontology is explained, where the concepts are expressed in two different nodes: Source of information (which is itself divided into two nodes: a statistical node and an interpreted node) and Analysis method, containing three types of node (Interaction-based, Action based, Interaction-Action-Stage based). The authors, finally sketch three possible usage for this ontology: the definition and authoring of cscl environments; the analysis and identification of collaborative features and finally the guide and coach of cscl activities.