April 5, 2007 11:51 AM
Generality & precision in RDF vocabulary
RDF language design goal as suggested in W3C specifications is to provide:
Generality - expression for the most propositions about any 'thing'
Precision - to provide accurate expression
RDF language does not provide meaning of a 'thing' in all contexts, it only provides a formal notion for representing a meaning in a particular context. Therefore a particular triple <subject, predicate, object> of a 'thing' may apply to one set of inference rules and not to another. It is difficult to write a RDF vocabulary that is complete and can be applied to all decidable inference systems. As new 'thing' is identified the triples are added to the vocabulary.
| subject=thing | predicate=property | object=value |
|---|---|---|
| speed | bitrate | Kbps |
| vehicle speed | km/hr | |
| narration speed | words/sec | |
| ... | ... |
RDF Application:
RDF Gateway from Intellidimension is a RDF application that can integrate RDF databases from different sources and provide results to user queries. The advantage of using RDF based systems as compared to relational databases is that access to the relational database is based on pre-defined keys whereas RDF provides a schema that does not require fixed keys. Intellidimension presents this RDF Gateway as a semantic web platform, the Data Service Interface provides an API that maps the external data source to a RDF triple data source. An SQL like query language RDFQL (RDF Query Language) is used to query the RDF database.
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