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RE: XML Schema vs DAML/RDF/RDFS

From: by way of <DSkvortsov@SonicFoundry.com>
Date: Fri, 19 Apr 2002 07:00:17 -0400
Message-Id: <200204191149.HAA30657@tux.w3.org>
To: www-rdf-interest@w3.org
[freed from spam trap -rrs]

Date: Thu, 18 Apr 2002 19:57:39 -0400 (EDT)
Message-ID: <93482DE01BC3614A8B9D48C7111F38030DDA6F@kenny.sonicfoundry.com>
From: Dima Skvortsov <DSkvortsov@SonicFoundry.com>
To: "'R.V.Guha '" <guha@guha.com>,
        "'www-rdf-interest@w3.org '" <www-rdf-interest@w3.org>


Just to elaborate this "distributed extensibility" issue that was pointed
out before.

XML provides a syntax and a set of tools for serialization. It can be used
to transmit RDF or pretty much anything else. It is how you use it that
makes a difference. In many cases XML is used just as a better recordset.
All the semantics is hardcoded in the application. The advantage of this
approach is its simplicity and performance. I do not see a reason why
someone working on say number crunching application that takes data from
proprietary XML would consider switching to RDF model.

The compelling value of RDF is its data model which is first a directed
labeled graph, second comprises a common understanding ;-) that graph's
nodes can represent resources all over the world and third is cumulative.
It's a perfect model for metadata. Looking deeper it's a very good model for
linking different things together. Through RDF this linking becomes
explicitly defined information which may be processed in a moreorless
standard fashion later on. RDFS/DAML allow to effeciently constrain RDF
statements so that mistakes/inconsistencies are avoided.

I do not feel that there is a lot of semantics within RDF itself. Rather RDF
explicitly adds semantics to resources it describes. Inference is
essentially side effect of RDF's graph data model. To be relevant inference
has to add value to the original resources.

With respect to your friend's work - I bet they are using RDF data model
without realizing it somewhere in their application. They should consider
making it real RDF if they want to be able to integrate with tools from
other domains. Indexing and search are probably the most obvious examples
here.

Best regards,
  Dima

P.S. Article (http://www.cetis.ac.uk/content/20010927172953) looks
interesting as description of where RDF turned out to be advantageous over
general XML in E-Learning.


-----Original Message-----
From: R.V.Guha
To: www-rdf-interest@w3.org
Sent: 4/17/2002 3:23 PM
Subject: XML Schema vs DAML/RDF/RDFS


I was talking yesterday to a friend whose is working with
some geologists who want to share data. They are of
course planning on using xml and are in the process
of writing up their xml schemas.

They have applications that do all kinds of sophisticated analysis
on this data. They have no need of doing the kinds of inferences
that rdfs/daml enables. Their apps do computations that are far
more complex and it would be easy for them to modify their
apps to make it do the few (if any) inferential facilities rdfs/daml
offers, if the need arises.

I tried to make a case for  rdf/rdfs/daml, but given the
substantially more tools available for xml/xml schema and their
lack of interest in simple inferences, I couldn't in good faith push
too hard for rdf/rdfs/daml.

So, should they be using rdfs/daml? Why?

guha
Received on Friday, 19 April 2002 07:49:18 GMT

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