The registry automatically generates crosswalks between namespaces based on relationships with the underlying semantic layer which is currently based on BSR.
BSR includes a mapping to Dublin Core (assumed to be DC 1.0). A mapping from ROADS/IAFA elements to Dublin Core (also DC 1.0) is also available (from http://www.ukoln.ac.uk/metadata/interoperability/dc_iafa.html).
The relationships between DC 1.0 elements and the BSR semantic units were registered. Rather than registering relationships between DC 1.0 elements and ROADS elements, relationships between ROADS elements and the semantic units were deduced.
A crosswalk from ROADS to DC 1.0 can now be generated based on relationships with the semantic layer.