Librarians sources and select content from their libraries and other institutions in their countries that is considered important and makes it available digitally within their digital repository systems (Local ADHL Nodes). Where content is in print format, it is digitized and described before making it available. While content is available within their own digital repository systems, it is also important that this content is made easily accessible via a central outlet and the ADHL Aggregation service makes this possible.
The ADHL Aggregation Service harvests content that has been curated by the librarians and hosted in their digital repositories into a single data set that can be searched centrally, and content accessed through it. The aggregation service therefore hosts content from all the participating Institutions ADHL repositories together to allow users to easily search and discover it from a single place.
The Aggregation Service uses a DSpace repository software manage the harvesting, discovery and access. The harvesting utilizes OAI-PMH (Open Archives Initiative’s Protocol for Metadata Harvesting) and OAI-ORE (Open Archives Initiative’s Object Reuse and Exchange) where possible so that references to the full text are also made available for users to access directly without going to the institution’s repository. Below is the architecture of the Aggregation service.