W3C home > Mailing lists > Public > public-vocabs@w3.org > December 2011

Re: using web-scale identifiers in microdata

From: Gregg Kellogg <gregg@kellogg-assoc.com>
Date: Wed, 21 Dec 2011 15:51:56 -0500
To: Jason Ronallo <jronallo@gmail.com>
CC: Thad Guidry <thadguidry@gmail.com>, public-vocabs <public-vocabs@w3.org>
Message-ID: <21B6868E-0E81-4EA4-ABEA-77DD9DD52864@kellogg-assoc.com>
On Dec 21, 2011, at 11:19 AM, Jason Ronallo wrote:

> On Wed, Dec 21, 2011 at 1:15 PM, Thad Guidry <thadguidry@gmail.com> wrote:
>> Identifiers (realist perspective identifiers) are really what you need.
>>  Oregano means different things to different folks in different parts of the
>> world.  A Thing With Many Names with 1 identifier is a good approach.  I am
>> not sure how a web developer from Puerto Rico designing a culinary site
>> would do this in microdata either.
>> Your example of Oregano, the ingredient from a realist perspective "The
>> dried leaves of the plant species Origanum vulgare" is not the same as
>> Oregano, the ingredient from a realist perspective "The dried leaves of the
>> plant species Plectranthus amboinicus, that is also commonly called
>> 'Orégano' or 'Orégano Brujo' or 'Cuban Oregano' if you live in Cuba, Puerto
>> Rico, etc."  Microdata deals with generalist views very easily, but I have
>> yet to see Microdata deal with things specifically within a realist
>> perspective, which seems straightforward with RDFa.
> Thad, could you give the basic example rewritten in RDFa? That might
> help me understand the point you're trying to make (which I'm not
> certain is what I really am concerned with).
> If I have a subject heading like "Oregano" which describes a book or
> photograph and I have an identifier like
> http://id.loc.gov/authorities/sh96005072#concept for that subject
> heading, is there a simple way in microdata to say that when I use the
> term "Oregano" as the value of an @itemprop that I mean
> http://id.loc.gov/authorities/sh96005072#concept (or
> info:lc/authorities/sh96005072)? I was just trying to use the recipe
> example, since it had been given before when discussing what I thought
> was a similar issue with using external identifiers for terms.

In RDFa, you could create a vocabulary and declare owl:equivalentProperty or owl:equivalentClass to map something like "Oregano" defined within that vocabulary to something else, but that doesn't really work for things that aren't Class or Property. Of course, OWL allows for an owl:sameAs association between something like http://my.vocabulary/Oregano to http://id.loc.gov/authorities/sh96005072#concept, but there is no way defined within RDFa to make this association. You'd need to perform OWL rule entailment to create this equivalence association (actually, owl:seeAlso might be more appropriate).

When using @vocab in RDFa, this does create a triple (<> rdfa:usesVocabulary <http://my.vocabulary/>) in the output graph that can be used to find vocabularies against which to perform entailment. It would be reasonable to do this for microdata as well, when we detect that a given vocabulary is used within a document based on the @itemtype values, but this has not been defined. Doing the actual OWL reasoning would be up to the application.


> Jason
Received on Wednesday, 21 December 2011 20:52:44 UTC

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