Sidewalk is an exploration into the use of superimposed information over digital library contents in an educational setting. We're researching tools over concept maps and strand maps.
As a part of the Sidewalk project, we are building several superimposed applications. Though these applications have different goals and use different information models, they all allow users to refer to sub-document selections in heterogeneous documents (stored in digital libraries). They also allow users to revisit those selections, and to retrieve excerpts and other related information from the selections. The superimposed applications provide these facilities with the help of the Superimposed Pluggable Architecture for Contexts and Excerpts (SPARCE), a middleware architecture and implementation.