W3C home > Mailing lists > Public > public-semweb-lifesci@w3.org > August 2006

Re: [BIONT] Teleconference 22nd August, 2006 - All times are US Eastern!

From: John Barkley <jbarkley@nist.gov>
Date: Tue, 22 Aug 2006 10:05:17 -0400
Message-ID: <195901c6c5f3$ff596010$8a3a0681@ncsl.nist.gov>
To: "Ivan Herman" <ivan@w3.org>, "Matthias Samwald" <samwald@gmx.at>
Cc: <public-semweb-lifesci@w3.org>, <jbarkley@nist.gov>

Mathias, Ivan,

>just a small datapoint to what you say. Although I essentially agree, we
>should not forget that even OWL-Lite requires a Description Logic
>reasoning engine (if one wants to use reasoning, that is).

I also think we should consider a recommended practice of using OWL Lite or
DL where possible (i.e., when the knowledge base can be expressed in no more
than DL).

With regard to the point "if one wants to use reasoning", unfortunately,
those who are only interested in querying must be aware of reasoning. For
example, the property "sameAs" is symmetric. Thus, if your knowledge base
has "A sameAs B", one would fully expect the query "?x sameAs A" to return
"B". However, query engines without reasoners won't. Therefore, one must put
"A sameAs B" and "B sameAs A" into their knowledge base in order to get the
expected results.

jb


----- Original Message ----- 
From: "Ivan Herman" <ivan@w3.org>
To: "Matthias Samwald" <samwald@gmx.at>
Cc: <public-semweb-lifesci@w3.org>
Sent: Tuesday, August 22, 2006 7:39 AM
Subject: Re: [BIONT] Teleconference 22nd August, 2006 - All times are US
Eastern!

Matthias,

just a small datapoint to what you say. Although I essentially agree, we
should not forget that even OWL-Lite requires a Description Logic
reasoning engine (if one wants to use reasoning, that is). For many,
even OWL Lite is too complicated for that. On the other hand, making a
simple (ie, unsophisticated but working) RDFS reasoning engine is
relatively simple and many programming environments already have that.

By the way, there is a line of R&D which tries to find a layer between
RDFS and OWL Lite (Ugly acronyms like pD*, RDFS++, OWL Feather appear
here and there.) The goal would be to extend RDFS with just some
additional features (usually inspired by OWL) but keeping the semantics
and the reasoning simple and essentially using the same model theoretic
approach as RDFS. A good example Herman ter Horst's paper:

Completeness, decidability and complexity of entailment for RDF Schema
and a semantic extension involving the OWL vocabulary, Herman J. ter
Horst, Journal of Web Semantics, (2005) 79-115.

regards,

Ivan

Matthias Samwald wrote:
> On Mon, 21 Aug 2006 19:08:36 -0400, Kashyap, Vipul wrote:
>
>
>> Discuss tasks for discussion at F2F in Amsterdam. Some examples
>> are: 1. OWL vs RDF (John Barkley?)
>
>
> I wonder what it is that makes people choose between RDFS or OWL. It seems
that people seem to think that RDFS is of better use for more technical,
'sloppy' representation of data, while OWL is of better use for more
ontological, concise representation of information. This might have some
advantage, as it would allow us to separate these two different grades of
ontological consistency. So when we are seeing an ontology formulated in
RDFS we expect less ontological commitment than we do with an ontology
formulated with RDFS. However, I am not sure if such a separation does
really exist (there are quite sloppy OWL ontologies and pretty clean RDF
schemas).
>
> I do not see many reasons for using RDFS instead of OWL lite or OWL DL
when creating new ontologies. First of all, merging an RDFS ontology with an
OWL lite/DL ontology always results in an ontology that is OWL Full -- 
something that most developers of OWL ontologies want to avoid. A little bit
of RDFS in a large ontology that otherwise is valid OWL DL will turn the
whole ontology into OWL Full.
> Therefore I would suggest that every new ontology should be developed as
OWL lite or OWL DL where possible. Even if we do not want to use reasoning,
OWL lite and DL have the advantage that they are less complex than OWL Full
and less prone to inconsistencies than RDFS -- and they do not ruin other
OWL lite/DL ontologies when they are merged.
>
> kind regards,
> Matthias Samwald
>
>
>

-- 

Ivan Herman, W3C Semantic Web Activity Lead
URL: http://www.w3.org/People/Ivan/
PGP Key: http://www.cwi.nl/%7Eivan/AboutMe/pgpkey.html
FOAF: http://www.ivan-herman.net/foaf.rdf#Me
Received on Tuesday, 22 August 2006 14:08:13 GMT

This archive was generated by hypermail 2.3.1 : Tuesday, 26 March 2013 18:00:44 GMT