http://www.well.com/%7Edoctorow/metacrap.htm

RDF schema and XML schema

We propose that both metadata diversity and interoperability can more easily be accommodated across the WWW if each metadata domain defines both an RDF Schema and an XML Schema for their domain in their registered namespace. The RDF Schema file will define the domain-specific semantic knowledge by specifying type hierarchies and definitions - based on the ISO/IEC 11179 standard for the description of data elements. The XML Schema file will specify recommended encodings of metadata elements and descriptions by defining types and elements, and their content models, structures, occurrence constraints and datatypes. In addition, the XML Schema will contain links to the corresponding semantic definitions in the RDF Schema file in the same namespace.

http://archive.dstc.edu.au/RDU/staff/jane-hunter/www10/paper.html