Personalized cluster-based semantically enriched web search for e-learning

Abstract

We present an approach for personalized search in an e-learning platform, that takes advantage of semantic Web standards (RDF and OWL) to represent the content and the user profiles. Personalizing the finding of needed information in an e-learning environment based on context requires intelligent methods for representing and matching the learning needs and the variety of learning contexts. Our framework consists of the following phases: (1) building the semantic e-learning domain using the known college and course information as concepts and sub-concepts in a lecture ontology, (2) generating the semantic learner's profile as an ontology from navigation logs that record which lectures have been accessed, (3) clustering the documents to discover more refined sub-concepts (top terms in each cluster) than provided by the available college and course taxonomy, (4) re-ranking the learner's search results based on the matching concepts in the learning content and the user profile, and (5) providing the learner with semantic recommendations during the search process, in the form of terms from the closest matching clusters of their profile. One important aspect of our approach is the combination of an authoritatively supplied taxonomy by the colleges, with the data driven extraction (via clustering) of a taxonomy from the documents themselves, thus making it easier to adapt to different learning platforms, and making it easier to evolve with the document/lecture collection. Our experimental results show that the learner's context can be effectively used for improving the precision and recall in e-learning search, particularly by re-ranking the search results based on the learner's past activities.