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Re: On the integration of Topic Maps and RDF

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Wed, 22 Aug 2001 10:35:30 -0400
To: andrei@derpi.tuwien.ac.at
Cc: lobrst@mitre.org, lacher@db.stanford.edu, gdm@empolis.co.uk, www-rdf-interest@w3.org
Message-Id: <20010822103530V.pfps@research.bell-labs.com>
Agreed, the information can be regenerated from the transformed RDF.
However, the regeneration cannot be performed in RDF, as some external
information is needed, whether in the form of some unspecified rules
language or in the form of informal side-agreements.

My view is that semantic transformations should not require any of this
extra information.


From: "Andrei S. Lopatenko" <andrei@derpi.tuwien.ac.at>
Subject: Re: On the integration of Topic Maps and RDF
Date: Wed, 22 Aug 2001 15:50:32 +0200

> I completely agree that semantic information must not be lost in
> transformation.
> But really it was not lost in "object layer" mapping suggested in the
> article.
> Semantic information about meaning of RDF resources transformed from XTM is
> implicitly declared in RDF  graph of resourses
> and could be extracted by inference engine. In F-Logic query example
> semantic of element is extracted in a such way (roleLabel condition).

I would not state that the extra information is implicit in the RDF.  It
requires extra information, such as inference rules, to be recovered.

> So there are several possible ways to map TM into RDF
> 
> 1 The one is preserving explicit semantic
>     XTM ->  RDF Resource graph +  RDF Schema (or DAML+ OIL, OIL)
> For example, such classes as country, natural-resource should be defined in
> the schema
> And then query should be asked using that new terms
> ...
> natural-resource -> pertoleum;
> ...
> 2 Another is "object layer"  mapping which just encode XTM graph as a RDF
> graph   and semantic is stored implicitly in that graph.
> The query should contain statements for extracting semantic information
> such in F-Logic  in the article
> ...
> tms:roleLabel->natural-resource;
> ...
> or semantic should be provided by inference engine
> 
> But from the point of view of the article  - to develop query engine which
> can also include XTM resources into  RDF
> both ways are suitable. The difference is only in queries. Information is
> not lost.

Not lost to a fully capable reasoner, such as a human.  However, it is lost
to an RDF (only)-capable agent.

> Maybe, for other applications it is neccesity to have explicitly declared
> semantic, bot not for this?
> 
> Best regards
> MSc Andrei S. Lopatenko
> Researcher
> Vienna University of Technology
> Extension Centre
> http://derpi.tuwien.ac.at/~andrei/

Peter F. Patel-Schneider
Bell Labs Research
Received on Wednesday, 22 August 2001 10:37:31 GMT

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