on using owl:sameAs - can you use skos:exactMatch instead?

106 views
Skip to first unread message

msksys

unread,
Oct 30, 2009, 12:42:19 PM10/30/09
to The New York Times Linked Open Data Community
Hi:

Thanks for the 'data' contribution to Semantic Web.

The following comment in your blog article on releasing the first
batch of links between NYT and linked data

http://open.blogs.nytimes.com/2009/10/29/first-5000-tags-released-to-the-linked-data-cloud/#comment-23941

identified the issue of using owl:sameAs and its implication to
rightsHolder.

Can you use skos:exactMatch?

This has the same meaning while does not result in the inference
owl:sameAs provides. In most cases this data is linking/matching
instances and not class concepts.


- Srikanth

Evan Sandhaus <sandhes@nytimes.com>

unread,
Oct 30, 2009, 12:51:36 PM10/30/09
to The New York Times Linked Open Data Community
Srikanth,

I like this suggestion, but I've also been urged to consider attaching
a skos:conceptScheme to the records and applying the license to that
scheme.

What do you think is the right approach?

~Evan


On Oct 30, 12:42 pm, msksys <msk...@gmail.com> wrote:
> Hi:
>
> Thanks for the 'data' contribution to Semantic Web.
>
> The following comment in your blog article on releasing the first
> batch of links between NYT and linked data
>
> http://open.blogs.nytimes.com/2009/10/29/first-5000-tags-released-to-...

msksys

unread,
Oct 30, 2009, 1:52:56 PM10/30/09
to The New York Times Linked Open Data Community
Evan:

I don't known the implications of associating license to the data as I
am not sure how it is be used in applications.

If I understand correctly, the combination of owl:sameAs and
rightsHolder and what it entails was the main issue.

I don't think it will be a problem if you keep dcterms:rightsHolder at
concept level and use skos:exactMatch instead of owl:sameAs.

- Srikanth


On Oct 30, 9:51 am, "Evan Sandhaus <sand...@nytimes.com>"
> > - Srikanth- Hide quoted text -
>
> - Show quoted text -

Hugh Glaser

unread,
Nov 3, 2009, 4:58:49 AM11/3/09
to The New York Times Linked Open Data Community
Interesting question.
Actually, when I went looking for the links (for sameAs.org) I had
expected to find skos:exactMatch and skos:closeMatch, as Evan had said
that they used skos, and was a little surprised to find owl:sameAs.
I would have accepted skos:exactMatch as equivalence links for
sameAs.org, by the way, and might even have taken skos:closeMatch if
they looked right.
So from my point of view, skos:exactMatch would be fine, and I think
you might avoid quite a bit of hassle by doing that? :-)
Mind you, to do it properly, I think you need to make sure that the
doamin and range are skos concepts.

Dan Brickley

unread,
Nov 3, 2009, 5:28:00 AM11/3/09
to nyt_linked...@googlegroups.com

I think there's a lack of clarity on whether there are any classes
that skos:Concept is truely disjoint with.

I have seen idioms in SKOS data (though I don't encourage it) where eg
a place or person concept also carries properties of that individual
(eg. age, location). Also sometimes people try to mix in OWL so a SKOS
concept for 'Dog' might also be an RDFS/OWL class. These are natural
explorations as the worlds of traditional thesauri and classification
systems blend into the more data-oriented RDFy stuff, but it makes it
hard to know quite what to recommend re skos:closeMatch...

Dan

Evan Sandhaus

unread,
Nov 3, 2009, 11:07:01 AM11/3/09
to The New York Times Linked Open Data Community
The domain and range of skos:broader, skos:narrower, skos:closeMatch,
skos:exactMatch and other skos:semanticRelation(s) is skos:concept and
the resources I'm currently mapping to ( at dbpedia and freebase) are
not of rdf:type skos:concept. Thus in these instances, as Hugh
suggested, it is inappropriate for us to link to resources that are
not of type skos:concept using skos:semanticRelation(s) predicates.

As a consequence, I seem to be left with two options, only one of
which seems good to me. Option 1 (the good one), restructure my RDF
to resolve the licensing and metadata issues and continue to use
owl:sameAs (and perhaps rdf:seeAlso where appropriate). Or option 2
( the bad one), coin my own predicates for describing the links from
my data to external resources. I am strongly disinclined to pursue
option 2, so I will continue to investigate option 1.

That being said, I can imagine instances where the
skos:semanticRelations(s) are appropriate (e.g. when linking to LOC
subject headings). So I am not entirely ruling out their future use,
just necessarily restricting it.

Thoughts?

Evan

============
Evan Sandhaus
Semantic Technologist
New York Times Research + Development

Kingsley Idehen

unread,
Nov 3, 2009, 11:47:26 AM11/3/09
to nyt_linked...@googlegroups.com
Evan Sandhaus wrote:
> The domain and range of skos:broader, skos:narrower, skos:closeMatch,
> skos:exactMatch and other skos:semanticRelation(s) is skos:concept and
> the resources I'm currently mapping to ( at dbpedia and freebase) are
> not of rdf:type skos:concept. Thus in these instances, as Hugh
> suggested, it is inappropriate for us to link to resources that are
> not of type skos:concept using skos:semanticRelation(s) predicates.
>
> As a consequence, I seem to be left with two options, only one of
> which seems good to me. Option 1 (the good one), restructure my RDF
> to resolve the licensing and metadata issues and continue to use
> owl:sameAs (and perhaps rdf:seeAlso where appropriate).
Yes, Please!

If you are talking about the same thing that has a known (and even
strong) identifier elsewhere, and the entity types are the same, please
use owl:sameAs. It your data space, and your claim to make.

Always remember the great "nearly pregnant" analogy in Pat Hayes Blogic
presentation.

The URI for owl:sameAs [1] is a live demonstration of why namespaces and
de-referencable URIs matter. You can de-reference [2] exactly what it
means :-) Note, it isn't symmetrical or transitive etc.. It is as
described, just a way of indicating, that from your vantage point (your
Linked Data Space): Entities X & Y refer to the same thing i.e.,
co-reference.


Links:

1. http://www.w3.org/2002/07/owl#sameAs
2.
http://linkeddata.uriburner.com/about/html/http/www.w3.org/2002/07/owl%01sameAs


--


Regards,

Kingsley Idehen Weblog: http://www.openlinksw.com/blog/~kidehen
President & CEO
OpenLink Software Web: http://www.openlinksw.com


Reply all
Reply to author
Forward
0 new messages