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On linking vocabularies (Was: SKOS for schema.org proposal for discussion)

From: Niklas Lindström <lindstream@gmail.com>
Date: Thu, 10 Oct 2013 01:10:36 +0200
Message-ID: <CADjV5jc=EWXVxRotWSSYpgsdKMDEKCEzfFEZHtNAxB1gnXDxHA@mail.gmail.com>
To: Martin Hepp <martin.hepp@ebusiness-unibw.org>
Cc: jean delahousse <delahousse.jean@gmail.com>, Ed Summers <ehs@pobox.com>, Guha <guha@google.com>, Thad Guidry <thadguidry@gmail.com>, Aaron Bradley <aaranged@gmail.com>, Bernard Vatant <bernard.vatant@mondeca.com>, PublicVocabs <public-vocabs@w3.org>, Dan Brickley <danbri@google.com>
Topic change (pun unintended)..

On Wed, Oct 9, 2013 at 6:20 PM, Martin Hepp <martin.hepp@ebusiness-unibw.org
> wrote:

> Hi all:
>
> The new element in schema.org and a few properties taken from SKOS would
> not prevent anybody from publishing a thesaurus in a proper Linked Data
> way, fully based on SKOS, with just the schema.org classes and properties
> attached in parallel.
>
> There is no either or, and we should keep in mind that the goals of
> advancing the idea of the "Semantic Web" or "Linked Data" and the goals of
> schema.org and its supporters are related, yet not identical.
>

Indeed. Though I think there is enormous value to gain from convergence in
technical approaches.

As I mentioned a while back, I share concerns similar to Ed's in principle:
using SKOS and only SKOS for this *should* be enough , logically. It is
only because of the convenience that I find any "importing" into
schema.orgviable at all. Thankfully, for the fans of formal logic and
such, by using
RDFS or better yet OWL, both points of view can be satisfied.

The key point is that there will quite likely be semantic drift unless the
schema.org class and properties are explicitly linked to their SKOS
counterparts. And I don't mean this in the "my OWL system will break" way –
I mean in a pure, social contract kind of way. This can be avoided with the
added level of precision that a:

    sdo:EnumConcept owl:equivalentClass skos:Concept .

statement brings (giving very little room for misinterpretation). I was
very glad to see that the Dataset configuration that Dan provided [1]
contains similar data. (It'd be great to have that incorporated into the
relevant term pages.) And I strongly support Dan's excellent points,
like: "Saying
they're the same is much simpler".

Following from this comes an important question: could the major consumers
of schema.org data (i.e. the big search engines) consider it feasible to
also use this mapping information as a way of declaring that the equivalent
terms – here skos:Concept – have equal standing in consumed data? By which
I mean that existing SKOS data, published in some schema.org approved
syntax such as RDFa, can be used as is, without any *need* to sprinkle in
these equivalent things? If that would be feasible, it would represent a
controlled, limited, but still formally giant leap forward in linking
vocabularies.

(The schema.org "aliases" would provide a very low barrier to entry, and do
fine for web developers doing some structured SEO. Further on, those
looking enhance the Knowledge Graph can use them too. But they'd explicitly
link further, in this case to SKOS, for those finding that particular venue
valuable (e.g. libraries) in *both* this and their own contexts.)

(With this, other parts of well-known vocabularies, like DC and FOAF, could
be explicitly mapped to lessen the need for choice or redundancy in certain
cases. And in a more distant future, perhaps this "vocabulary aliasing"
practice could be extended to take other equivalencies than the ones
schema.org itself declares into account. E.g. using a pattern like the one
we defined in RDFa 1.1, called "Vocabulary Expansion" [2].)

Cheers,
Niklas

[1]:
https://dvcs.w3.org/hg/webschema/file/3879206aa3f7/schema.org/ext/dataset.html
[2]: http://www.w3.org/TR/rdfa-syntax/#s_vocab_expansion



> Martin
>
> On Oct 9, 2013, at 6:16 PM, jean delahousse wrote:
>
> > Hello,
> >
> > In the use cases I know about thesaurus or taxonomy publishing, you want
> several publication supports:
> > - xml/skos file to be downloaded
> > - sparql endpoint to query the controlled vocabulary
> > - html version for search engine and human navigation
> >
> > For each publication you want to provide all the semantic information in
> the most reusable way. It seems the best way to provide the semantic of a
> controlled vocabulary publish in html pages would be to use schema.org if
> you could find the proper class and properties.
> >
> > Find here a data.bnf.fr page about a concept belonging to the Rameau
> thesaurus, it has no schema.org annotations, as there is no such
> properties avalaible today in schema.org, but for the related pages about
> works and persons it was possible to map part of the frbr properties into
> schema.org properties and then to publish more semantic in the html page.
> > concept : http://data.bnf.fr/13319064/science_politique/
> > person classified with the concept :
> http://data.bnf.fr/12085503/thomas_jefferson/
> >
> > "Science_politique" deserve the same chance to be well described in a
> web page as cookie recipe or a song.
> >
> > As you see in the data.bnf.fr it, there is no more complexity for a
> user to understand a page about a person, a work or a concept.
> >
> > data.bnf.fr also publish the rameau thesaurus as xml/skos files as it
> publishes the works as xml/rdf files using a bnf ontology mainly based on
> frbr.
> >
> > Jean
> >
> > 2013/10/9 Ed Summers <ehs@pobox.com>
> > On Wed, Oct 9, 2013 at 8:24 AM, jean delahousse
> > <delahousse.jean@gmail.com> wrote:
> > > About use cases, a very simple one is the publication of a thesaurus,
> for
> > > example FAO or Eurovoc in the web, with one page for each concept
> showing
> > > its pref-label and alt-labels in various languages, definition,
> > > exactMatch...
> >
> > Thanks for responding Jean. Can you describe why you would prefer to
> > publish this structured data in your HTML using schema.org rather than
> > using SKOS directly?
> >
> > //Ed
> >
> >
> >
> > --
> > Jean Delahousse
> > JDC
> >
> ----------------------------------------------------------------------------------------------------
> > delahousse.jean@gmail.com - +33 6 01 22 48 55
> http://jean-delahousse.net/
> >
> >
>
> --------------------------------------------------------
> martin hepp
> e-business & web science research group
> universitaet der bundeswehr muenchen
>
> e-mail:  hepp@ebusiness-unibw.org
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>
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Received on Wednesday, 9 October 2013 23:11:34 UTC

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