Integrating Learning Object Repositories Using a Mediator Architecture

We propose a mediator architecture that allows a learning system to retrieve learning objects from heterogeneous repositories. A mediating component accepts queries formulated in a uniform query language, translates them into repository specific queries and passes them to each connected repository. For the translation of queries, a novel ontology-based query-rewriting method has been developed. The architecture has been realized in the Web-based, user-adaptive and interactive e-learning environment ActiveMath. Currently, it enables the ActiveMath’s course planner to access four heterogeneous learning object repositories.