Herbert Van de Sompel
Technical Staff Member, Research Library
Los Alamos National Laboratory
For the past year, the Digital Library Research and Prototyping Team of the Los Alamos National Laboratory has architectured and created an initial implementation of a repository infrastructure aimed at ingesting, storing, and disseminating a vast collection of locally held digital scholarly materials. In the architecture, complex digital objects are represented using an XML wrapper structure that is compliant with a profile of the MPEG-21 Digital Item Description Language. Each batch of ingested digital objects is stored as an individual OAI-PMH repository. An OAI-PMH Federator is introduced as a single point of access to the multitude of OAI-PMH repositories. Downstream applications can access the OAI-PMH Federator to obtain feeds of DIDL objects, and use those, for example, to build discovery services based on contained items. The OAI-PMH Federator disseminates DIDL objects either as stored or with transformations applied to them. For the dissemination of an individual item contained in a DIDL object, the architecture builds on the extended expressivness offered by the upcoming NISO OpenURL Framework Standard. Through an OpenURL Resolver, an individual item contained in a DIDL object, or a transformation thereof, can be requested. Dissemination of the item can be handled in a context-sensitive manner, e.g. different requesters can receive different disseminations of the same item.
Although the architecture has been defined for deployement within the context of the Los Alamos National Laboratory, its core properties seem to offer some potential for the creation of a context-sensitive infrastructure to access items stored in distributed digital libraries.