Representing Contextualized Information in the NSDL
  The NSDL (National Science Digital Library) is funded by the National Science Foundation to advance science and match education. The inital product was a metadata-based digital library providing search and access to distributed resources. Our recent work recognizes the importance of context - relations, metadata, annotations - for the pedagogical value of a digital library. This new architecture uses Fedora, a tool for representing complex content, data, metadata, web-based services, and semantic relationships, as the basis of an information network overlay (INO). The INO provides an extensible knowl-edge base for an expanding suite of digital library services. 
Carl Lagoze, Dean Krafft, Tim Cornwell, Dean Eckstrom, Susan Jesuroga,   Chris Wilper