Re: RDF vs. just XML

> Tim Berners-Lee answer is at
> http://www.w3.org/DesignIssues/RDF-XML.html

Just one of a series of great pages about RDF...

> Now, the devil's advocate position would be: "the
> expressions are hidden from the end user anyway
> and maybe ADL will be so utterly simple that this
> consideration is minor"

I very much doubt it! The list of requirements that you have listed for ADL
points to something altogether very complex and extreme: an ADL language is
by definition going to be about complex logical and semantic processing.
Quoth TimBL:-

"Resource Description Framework (RDF) is a foundation for processing
metadata; it provides interoperability between applications that exchange
machine-understandable information on the Web. RDF emphasizes facilities to
enable automated processing of Web resources and serves as the foundation
for the "Semantic Web." [...] RDF [...] will enable the Web of the future."

This means RDF gives us a great deal of processing power in its framework
"RDF emphasizes facilities to enable automated processing of Web resources",
and that offers distinct advantages over XML IMO.

> So one of the things we'll want to look for is potential
> real-life assertions and queries that will indeed be far
> simpler to implement in RDF than in XML.

I think the point that Mr. Berners-Lee was trying to make is that it isn't
possible in XML without going to great lengths.  XML simply wasn't set up
for making assertions and for querying, whereas that is exactly the intent
of RDF. Note that Mr. Berners-Lee also said:-
"If you haven't gone to the trouble of making a semantic model, then you may
not have a well defined one. [...] I'll end this with some examples of the
last problem [SBP: see http://www.w3.org/DesignIssues/RDF-XML.html]. Clearly
they can be avoided by good design even in an XML system which does not use
RDF. Using RDF makes things easier." - ibid.

Summary: RDF is clearly for the Web of the future (the Semantic Web), but we
have to decide if that future starts here and now with ADL, or if we are
just going to use other technologies until such as time as more of an
infrastructure has been laid down.
In the defence of RDF, there are already a lot of RDF parsers we could use
and convert (not withstanding Schematron), see
http://www.w3.org/RDF/#developers under RDF Parsers. We could "adapt" some
of these for use with ADL couldn't we?

Kindest Regards,
Sean B. Palmer
http://xhtml.waptechinfo.com/swr/
http://www.w3.org/WAI/ER/
http://www.w3.org/WAI/GL/
"Perhaps, but let's not get bogged down in semantics."
   - Homer J. Simpson, BABF07.

Received on Monday, 27 November 2000 16:55:01 UTC