W3C home > Mailing lists > Public > semantic-web@w3.org > May 2008

Re: Managing Co-reference (Was: A Semantic Elephant?)

From: Michael F Uschold <uschold@gmail.com>
Date: Wed, 14 May 2008 16:25:07 -0700
Message-ID: <406b38b50805141625lda252bah1741b55cfb8eeec0@mail.gmail.com>
To: "Aldo Gangemi" <aldo.gangemi@cnr.it>
Cc: "Tim Berners-Lee" <timbl@w3.org>, "Sören Auer" <auer@informatik.uni-leipzig.de>, "Semantic Web Interest Group" <semantic-web@w3.org>, "Chris Bizer" <chris@bizer.de>, "Frank van Harmelen" <Frank.van.Harmelen@cs.vu.nl>, "Kingsley Idehen" <kidehen@openlinksw.com>, "Fabian M. Suchanek" <f.m.suchanek@gmail.com>, "Tim Berners-Lee" <timbl@csail.mit.edu>, "Jim Hendler" <hendler@cs.rpi.edu>, "Mark Greaves" <markg@vulcan.com>, georgi.kobilarov@gmx.de, "Jens Lehmann" <lehmann@informatik.uni-leipzig.de>, "Richard Cyganiak" <richard@cyganiak.de>, "Frederick Giasson" <fred@fgiasson.com>, "Michael Bergman" <mike@mkbergman.com>, "Conor Shankey" <cshankey@reinvent.com>, "Kira Oujonkova" <koujonkova@reinvent.com>, a.o.jaffri@ecs.soton.ac.uk, hg@ecs.soton.ac.uk, icm@ecs.soton.ac.uk
Aldo notes the problems with using owl:sameAs to mean similarity. Such uses
are often incorrect, and Aldo suggests using something like rdfs:seeAlso,
skos:related, instead. These relations are too weak, unfortunately.

There is an interesting proposal for managing URI snyonyms that attempts to
have a middle ground, weaker than owl:sameAs, but much stronger than
rdfs:seeAlso or skos:related.   They suggest an infrastructural approach
[apparently] outside the logic for managing URI synonyms. It is a quite
clever approach, but still has some challenges.  Here are portions of a note
I just sent the authors of a paper, which relates to this question.

Afraz, Hugh and Ian:

I just read your workshop paper:
Managing URI Synonymity to Enable Consistent Reference on the Semantic
Web<http://eprints.ecs.soton.ac.uk/15614/1/camera-ready.pdf>


   1. I wholeheartedly agree that owl:SameAs is too strong in many cases. A
   weaker relation is needed. However, you don't offer  weaker relation and
   give it semantics. Instead, you do a kind of sleight of hand and remove it
   from the logic.  Without  a semantics, what is a system developer to do with
   the fact that two URIs are in the same bundle?  What are the inferential
   impliciations?

   Example: IMHO it is a bad idea to say that Spain the political entity is
   the same as Spain the geopolicial region. This ontological distinction has
   been clear documented in DOLCE, for example. They are different, and should
   have different URIs.  Conflating them will cause problems.  Of course,
   making this and many other ontologically 'sound' distinctions can cause its
   own problems, by adding complexity -- a tradeoff. Without any semantics of
   inCRS_Bundle, there is no way to tell if it is semantically correct.
   2. Do you have any idea of the scalability of this approach?

Michael



On Wed, May 14, 2008 at 2:24 PM, Aldo Gangemi <aldo.gangemi@cnr.it> wrote:

>        • Problem 2) even if you can find the links, prolific use of
>> owl:sameAs will create computational problems.
>>
>>
>
> Michael,
>
> there is an item related to Problem 2), already discussed on LOD and
> elsewhere last year, i.e. the use of
> owl:sameAs, which is a formal relation of identity, to denote generic
> "similarity", or even "relatedness"
> between two entities.
>
> owl:sameAs is great to co-reference persons, places, etc. It is buggy when
> used to relate e.g. foaf:Person
> instances to persons' homepages, or a city as from Cyc to a wikipedia
> article of that city (as done in DBpedia).
>
> In previous discussions, besides some weak good practices [1], I found no
> attempt to discourage its use for similarity.
> This use is not needed. We can use e.g. rdfs:seeAlso, skos:related, or any
> other local relation instead.
>
> It is reasonable, as Richard Cyganiak wrote at the time, that we have to
> work around the quirks [2],
> nonetheless, if there is no real need, why should we work around the quirks
> caused by a pointless identity
> assumption?
>
> Notice that ignoring owl:sameAs is not a good solution. We need some
> trade-off between simplicity
> and formality. A basic similarity relation is perfect, and then those
> triples can be worked out automatically,
> by means of appropriate metamodels, e.g. as proposed in [3].
>
> Aldo
>
> [1] Bernard Vatant suggested some good practice of mutual linking:
>
> http://universimmedia.blogspot.com/2007/07/using-owlsameas-in-linked-data.html
>
> [2] Cyganiak quote:
>
>> People who want to re-use your data will learn to work around its quirks
>> and idiosyncrasies.
>> Dealing with the quirks is a part of re-using data, it always was, and it
>> always will be.
>>
>>
> [3] http://www.ibiblio.org/hhalpin/irw2006/vpresutti.pdf from IRW
> workshop: http://www.ibiblio.org/hhalpin/irw2006/
>
>
> _________________________________
>
> Aldo Gangemi
>
> Senior Researcher
> Laboratory for Applied Ontology
> Institute for Cognitive Sciences and Technology
> National Research Council (ISTC-CNR)
> Via Nomentana 56, 00161, Roma, Italy
> Tel: +390644161535
> Fax: +390644161513
> aldo.gangemi@cnr.it
>
> http://www.loa-cnr.it/gangemi.html
>
> icq# 108370336
>
> skype aldogangemi
>
>
>
Received on Wednesday, 14 May 2008 23:25:49 GMT

This archive was generated by hypermail 2.3.1 : Tuesday, 26 March 2013 21:45:22 GMT