Re: Modeling change in and between schemes using SKOS - the problem of persistent URIs

Hi Danny:

On 30-Aug-06, at 2:07 AM, Danny Ayers wrote:

> (Oops, after typing this I noticed the posts that followed - apologies
> if there are points already made I missed)
>
> On 8/28/06, Joseph Tennis <jtennis@interchange.ubc.ca> wrote:
>
>> 1. SKOS postulates a concept exists independent of a scheme
> Ok.
>
>> 2. This means that a concept can exist in many schemes (further  
>> demonstrated
>> by SKOS's inScheme)
> Ok.
>
>> 3. However, each scheme delimits the meaning of a concept by its
>> relationships with other concepts in the scheme.
>
> Does the scheme do the delimiting, or the set of other concepts?
> (which as stated in 1. exist independent of a scheme).

Interesting question.  What's the difference between Scheme and Set  
of Other Concepts?

>
>> 4. Change notes, as properties of concepts, are not linked to the  
>> scheme in
>> which the change applies.
>
> Ok, this seems to be the nub...
>
>> 5. We are left to ask: how do we model scheme specific changes to  
>> concepts
>> without signaling a new URI?
>
> - so why is this a problem?
>
>> You can see an illustration of the problem at:
>> http://www.ischool.washington.edu/sasutton/skos/ 
>> Concept_History_New.html
>
> An excellent illustration, although a little more info on the
> motivation - the kind of case which leads to this problem - would be
> helpful.

DDC has evolved over the 19th into the 21st century.  During that  
time concepts are represented in various ways with various  
relationships (as seen to some degree in Notation and See Also  
references).

In DDC in 1911 we have the concept of Eugenics as a Science.  It has  
changed.  How do we model such changes in SKOS?

>
>> You can also see how we are trying to solve the problem: by  
>> introducing an
>> ConceptInstance as well as a Concept.  This too can be seen at the  
>> above
>> URL.
>
>
> With ConceptInstance it does seem like you're still in effect minting
> new Concepts...I'm not entirely clear on why doing this directly would
> be a problem.

The proliferation of less-than-meaningful URIs is something we want  
to avoid in the semantic web right?  We want to interoperate via URI  
(among other things), so we want our URI's to be meaningful yes?

>
> My naive impression is that this could cause problems later, as it's
> modifying (/adding to) the Concept part, when (if I understand
> correctly) the problem is actually with the modelling of scheme
> changes. This looks like an n-ary relation tying together a specific
> scheme, specific change note and (common) concept.
>
> A change note which applied to both to a concept and a scheme might
> help, but there's a snag in that changeNote/historyNote are
> properties. I wonder if you made a class Note this might help:
>
> Concept
>    historyNote
>           Note
>                associatedWithScheme
>                    ConceptScheme
>
>
> Or maybe you could maybe start from the scheme, with a subclass
> AnnotatedScheme which could include a collection of change notes.
>

Right!  So that's the issue!  How can SKOS handle this elegantly?  We  
don't want a clumsy solution to something that every scheme that goes  
through versions is going to have to deal with.

Thanks for thinking about this!
joe


> Cheers,
> Danny.
>
>
>
> -- 
>
> http://dannyayers.com



Joseph T. Tennis, PhD
Assistant Professor
Coordinator for the MAS and MLIS First Nations Concentration
School of Library, Archival and Information Studies
The University of British Columbia
301 - 6190 Agronomy Road
Vancouver, BC V6T 1Z3
CANADA
phone: 1.604.822.2431
fax: 1.604.822.6006
jtennis@interchange.ubc.ca
http://www.slais.ubc.ca/PEOPLE/faculty/tennis-p/index.htm

Received on Friday, 1 September 2006 17:01:16 UTC