Taking advantage of the Semantics of a Lesson Graph based on Learning Objects

Lesson graphs are composed of Learning Objects (LOs) and include a valuable amount of information about the content and usage of the LOs, described by the LO metadata. Graphs also make explicit the links between the LOs (i.e. the graph semantics). This article proposes a conceptual model for taking advantage of this information. This model is based on an original diffusion process that copes with the problem of lesson graphs where some metadatas are missing. Two applications of the model are described and were implemented over a previously developed lesson authoring tool whose goal is to facilitate the lesson authoring process.