On the integration of Topic Maps and RDF from Peter F. Patel-Schneider on 2001-08-22 (www-rdf-interest@w3.org from August 2001) (original) (raw)

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 UTC