A 2-tiers p2p architecture to navigate the learning objects sea

Learning object repositories (LORs) are a strategic asset for e-learning. In a quite short period the scenario of use quickly changed from an initial scarcity of learning objects (LOs) to an overabundance disorienting users. To address this problem, we present a conceptual model which leverages on the creation and sharing of comments about the use of LOs as experimented by learners. These comments originate a superstructure on interrelated and distributed LOs in the form of an annotated graph-of-comments. By relying on the graph structure, an ordering feature and a mechanism for extracting personalized views are provided. Observing that both LORs and users are expected to belong to different communities, we propose a two-tiers architecture based on hybrid peer-to-peer technology efficiently realizing navigation on LORs.