Re: [xml-dev] The Semantic Web: An Introduction

[James Strachan <james_strachan@yahoo.co.uk>]

----- Original Message -----
From: "Bullard, Claude L (Len)" <clbullar@ingr.com>
> One should not confuse "data on the web" as
> a purely Semantic Web notion.

Agreed. XML data on the web is a Good Thing (tm) for many reasons.

Also alot of semantics exist outside of RDF. There are many standard XML
schemas with well defined semantics, few (if any) of which have an RDF
'transformation' or adornment. e.g. RSS, NASDAQ-DTD, SwiftML, fixML, fpML,
MathML etc.

What I was trying to say was there will be a huge amount of data available
as XML with well defined semantics available somewhere, but probably not in
RDF any time soon. Are the SW people trying to tackle this?


> Providing a
> semantic cue and a structure to data is
> markup in its most basic form and most
> other databases as well.  Ontologies as
> such, are classification systems and not
> novel.   So far, the distinguishing charcteristic
> of the Semantic Web effort is to add the
> well-known but non-interoperable technologies
> of inferencing engines to the web architectures.

Agreed. I'm just wondering aloud how the RDF world works with the XPath,
XSLT, XML Schema, XLink, XPointer worlds. There seems much overlap or
avenues of possible collaboration. e.g. rules could be written using XPath
expressions.

I guess I've never truly grokked RDF, probably as I don't actively use
inference engines. Do other people use RDF other than for inference engines?


> A cursory review suggests that RDF is well
> suited to inference-capable databases (eg,
> expert system types with chaining, a la
> prolog).  Given that XML is only a syntax
> for creating languages, it is the responsibility
> of the application developer to determine
> the suitability and applicability of any
> given XML-conformant language.  A pure RDF
> web is very unlikely.

Agreed - though it should be possible to bind well defined XML languages
into an inference engine via (say) XSLT. The requirement is well defined
semantics of the XML language, not an RDF document per se.


> How data strutured with an
> XML Schema and systems using RDF classifications
> are to interoperate is a good question that
> should be explored by this list.

Agreed. It might be useful to be able to make assertions about arbitrary XML
Schema documents in an RDF-like way (in a seperate document) and then apply
them to XML instance documents.

James



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