  NCore is an open source architecture and software platform for creating
flexible, collaborative digital libraries. NCore was developed by the National
Science Digital Library (NSDL) project, and it serves as the central technical
infrastructure for NSDL. NCore consists of a central Fedora-based digital
repository, a specific data model, an API, and a set of backend services and
frontend tools that create a new model for collaborative, contributory digital
libraries. This paper describes NCore, presents and analyzes its architecture,
tools and services; and reports on the experience of NSDL in building and
operating a major digital library on it over the past year and the experience
of the Digital Library for Earth Systems Education in porting their existing
digital library and tools to the NCore platform.
