RDF necessary to SW? - was Issues with XML and Semantic Web ?
On Tue, 09 Nov 2004 20:29:44 -0800, Tim Bray <tbray@t...> wrote: > On Nov 9, 2004, at 9:18 AM, DuCharme, Bob (LNG-CHO) wrote: > > the amount of practical, usable RDF data still seems > > remarkably small. > > Just a reminder that the RDF.net challenge is still open: see > http://www.tbray.org/ongoing/When/200x/2003/05/21/RDFNet FWIW, my recent epiphany that the Semantic Web  stuff is not as wacky as I once thought came partly through the possibly heretical thought that there is no need to convert much actual data, and perhaps not much metadata, into RDF. The powerful Semantic Web idea for me is the notion of an ontology -- meta-metadata if you will -- that relates concepts and relationships in real-world metadata (service definitions, XML schemas, data dictionaries, etc.) to one another in a way that supports automated inference. DAML-OIL and OWL are RDF under the covers, I guess, but that doesn't strike me as any more interesting than the fact that they are serialized as XML. The power AND the challenge comes from the modeling exercise of defining a network of resource-predicate-value assertions that can be navigated to automate useful tasks. RDF, then, is simply the mechanism that popular ontology languages employ for describing RPV assertions, or so my thinking goes. Of course, one logically could build the Semantic Web from the bottom up by making the actual information out there on the web, in databases, etc. RDF-compatible so that generic reasoners could follow the chain of resource definitions back to something that an application understands. I'm just predicting that it is far more likely, and far more practical in real enterprise projects, for applications to gradually migrate the logic for finding and relating data and metadata from being hard coded to being inferences over an ontology. That has a couple of advantages: the extreme ugliness of RDF syntax is not a problem for very many people, and there is a plausible evolutionary path from the world of today to the vision for tomorrow. After all, any domain that is well defined and stable enough to be even plausibly managed with hard coded relationships is obviously well defined and stable enough to be modeled with an ontology. Using semantic technology improves the ability to accommodate change and diversity, using an explicit model in a single language rather than multiple implicit models in various programming and database languages. Furthermore, one can use conventional RDBMS and XML technology (and conventional application code) to manage all the data and existing metadata, the only information that potentially would be managed with exotic triple stores and new query languages is the ontology itself. Anyone want to point out flaws in this assessment?  Apropos John Loutzenhiser's comments in the parent thread, I'm talking about applying the technologies that come out of the Semantic Web activity to relatively constrained and static domains for which a top-down formal semantics approach is appropriate. I agree that applying them to the Web as a whole will be a "bloated, brittle, bitter disappointment".
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