W3C home > Mailing lists > Public > public-vocabs@w3.org > January 2013

Re: Should we adopt SKOS?

From: Bernard Vatant <bernard.vatant@mondeca.com>
Date: Fri, 11 Jan 2013 00:05:05 +0100
Message-ID: <CAK4ZFVHZiG1M+n+Q7-3dbQOGV5BeLUaa+GzV6ok1YhR0FpQHDA@mail.gmail.com>
To: Martin Hepp <martin.hepp@ebusiness-unibw.org>
Cc: public-vocabs@w3.org, Pierre-Yves Vandenbussche <py.vandenbussche@gmail.com>
Hello all

I'm both glad to see those issues being open, and at the same time puzzled
that they come so late in the history of vocabularies :)

Just browse the Linked Open Vocabularies cloud following dependency links
to figure that every vocabulary relies on average upon 5 other vocabularies
in the cloud, half are used for proper semantic extension through
rdfs:subClassOf, rdfs:subPropertyOf, owl:equivalentClass,
owl:equivalentProperty, rdfs:range, rdfs:domain or more complex OW
constructions (restrictions), half are used to represent metadata. And of
course each of of those 5 relies on 5 other ones and so on. Basically it's
a small world where any change somewhere can impact a great part of the
cloud.

But who actually cares? There is indeed absolutely no proven mechanism,
either technical or social, allowing to track those changes and take them
into account.

#1 If my vocabulary V2 relies on V1, how do I know that V1 has changed?

#2 If my vocabulary V1 is used by V2, how do I know, and should I ping the
responsible of V2 if I make changes in V1? And should I consider how my
vocabulary is re-used by V2 before making any change? Suppose Dan Brickley
decides for some reason that the class foaf:Person is deprecated. What
happens next? (of course he won't do that, but you get the point)

#1 is the simplest to address. Tools like the "LOV-Bot" developed by
Pierre-Yves, mentioned earlier today in another thread, can track changes
in published vocabularies by scanning them on a daily basis.

Addressing #2 directly is more tricky. A good social practice would be for
the creator of V2 to ping the owner of V1 saying hello, your vocabulary V1
is cool, I've used it in V2 which is published here. Do you think I
interpreted it correctly? I made extensions that you light consider
including etc etc. Sort of starting a social relationship, that is. But who
is actually doing that now? I've heard many vocabulary creators complaining
their excellent vocabularies are mostly ignored. But have they started by
making this?
This of course supposes that every published vocabulary have some
responsible and visible curator. For some of them it's quite obvious to
find, and they gladly respond when asked (Hi Martin).
But even if they do now, what will happen next year, and ten years from
now? Who will inherit FOAF, GoodRelations, Geonames Ontology ... and many
more.

Dublin Core conference in September will be exactly about this. How do we
Link to the Future? That seems a good target for those wanting to work on
those issues seriously.
http://dcevents.dublincore.org/index.php/IntConf/dc-2013

Best

Bernard


2013/1/10 Martin Hepp <martin.hepp@ebusiness-unibw.org>

> Hi Ivan, all:
>
> FYI: For GoodRelations, we will provide a formal, OWL/RDFS-based mapping
> in the next GR service update, i.e. for an RDF client who can handle
> owl:sameAs, rdfs:subClassOf, rdfs:subPropertyOf, owl:equivalentProperty,
> and owl:equivalentClass (in a moderate, pragmatic way - no need for full
> OWL reasoning), it will not matter whether GoodRelations is used in the
> original namespace or in the schema.org namespace.
>
> E.g.
>
> @prefix schema: <http://schema.org/> .
> @prefix gr: <http://purl.org/goodrelations/v1#>.
>
> schema:ParcelService a owl:Class ;
>         owl:equivalentClass gr:DeliveryModeParcelService .
>
> By that, we can also easily bridge the slight differences in naming
> conventions between the two namespaces, as documented in [1]
>
> For the near future, I think that defining such a thing as a "best
> practice" should be sufficient. We could then put the actual task on the
> shoulders of the maintainers of the original vocabulary.
>
> However, should schema.org evolve beyond ca. 1000 types and include
> components from more than ca. 10 vocabularies that are not fully stable, we
> will need a more flexible and scalable approach.
>
> Ideally, we would already sketch the architecture for this future now
> (nice PhD or research paper topic) while we muddle through with the
> pragmatic approach sketched above.
>
> Martin
>
> [1]
> http://wiki.goodrelations-vocabulary.org/Cookbook/Schema.org#Naming_Differences
>
>
> On Jan 10, 2013, at 11:00 AM, Ivan Herman wrote:
>
> > Exactly...
> >
> > I think it would worthwhile to have some general discussion on how to
> maintain equivalence between what you call 'adopted' vocabularies and their
> original. We do not want to disenfranchise users who happen to use (or have
> used) the original namespace/terms.
> >
> > Putting my RDF hat on, it would/could be possible to set up some machine
> readable files defining the equivalences although, I am afraid, a simple
> owl:sameAs, owl:samePropertyAs, etc, may not work in all cases. There is
> also an issue of who would manage those equivalences: is it the job of
> schema.org? The 'authors/owners' of the original vocabularies? This group
> as a community? I honestly do not know. And I am also not 100% whether this
> is the right approach.
> >
> > At the moment we have two 'adopted' vocabularies (GoodRelations and
> rNews); out of those GR has a significant adoption already in its original
> namespace, I am not sure about the rNews figures. LRMI, afaik, does not
> have a non-schema version, so that is not an issue. But if we begin to
> discuss SKOS, SIOC and the others, then it is worthwhile having this
> discussion before it gets out of hand...
> >
> > Whether it is a workshop or simply a discussion on this list: I do not
> know. I would certainly like to hear the opinions on this list.
> >
> > Thanks Martin, for raising this.
> >
> > Ivan
> >
> > On Jan 9, 2013, at 19:28 , Martin Hepp <martin.hepp@ebusiness-unibw.org>
> wrote:
> >
> >> I would like to add at this point that I see schema.org first and
> foremost as an effort to provide ex ante schema alignment under a common,
> easily accessible umbrella, following a "schema alignment before data
> publication" paradigm.
> >> This makes authoring markup easier (no namespace traversals) and
> reduces the complexity for consuming clients.
> >>
> >> This having said, I would also rather suggest to import a pragmatic
> subset of SKOS into schema.org, in a fashion similar to the external
> enumerations pattern in use now and the additionalType property solution
> for external type systems.
> >>
> >> An general open question is how we maintain the alignment of the
> original vocabularies (LRMI, GoodRelations, maybe SKOS, SIOC, ...) with
> their conceptually equivalent elements in schema.org.
> >>
> >> In GoodRelations, we will simply try to keep both in sync manual, which
> seems reasonable given that the conceptual model is pretty stable.
> >>
> >> In the long run, however, we will need to find a solution that combines
> the centralized schema.org approach with distributed contributions from
> various domains.
> >>
> >> Maybe that is an interesting topic for a new schema.org workshop in
> 2013?
> >>
> >> Best
> >>
> >> Martin
> >>
> >>
> >>
> >> On Jan 9, 2013, at 7:00 PM, Dan Brickley wrote:
> >>
> >>> +Cc: Jamie
> >>>
> >>> On 9 January 2013 16:29, Richard Wallis <richard.wallis@oclc.org>
> wrote:
> >>>> Coming from the bibliographic world, specifically chairing  the
> Schema Bib
> >>>> Extend Group[1] (who are building a consensus around a group of
> proposals
> >>>> for Schema.org extensions for bibliographic resources, before
> submitting
> >>>> them to this group), I am identifying situations where being able to
> model
> >>>> things as SKOS[2] Concepts held in ConceptSchemes would make a great
> deal of
> >>>> sense.
> >>>>
> >>>> Working with colleagues we were finding ourselves almost reinventing
> the
> >>>> SKOS model in [proposed] Schema.org vocabulary.
> >>>>
> >>>> The introduction of External Enumerations[2] provided the ability to
> link to
> >>>> lists of things controlled by external authorities.  An approach used
> widely
> >>>> in the bibliographic and other domains – Library of Congress Subject
> >>>> Headings[4] for example.  Many of these authorities are modelled
> using SKOS
> >>>> (Concepts within ConceptSchemes) which introduces a consistent
> structured
> >>>> way to describe relationships (broader/narrower), language specific
> >>>> preferred labels, etc.
> >>>>
> >>>> Sub-typing Intangible for Concept and ConceptScheme, it would be
> >>>> comparatively easy to introduce SKOS into Schema.  The benefits I
> believe
> >>>> being to add even more value to External Enumeration; providing a
> flexible
> >>>> simple-ish yet standard pattern for marking up lists of concepts and
> their
> >>>> interrelationships; provide a very easy way for already published
> >>>> authoritative lists of concepts to adopt Schema.org and provide
> valuable
> >>>> resources for all to connect with.
> >>>>
> >>>> For instance VIAF[4] the Virtual International Authority File, a well
> used
> >>>> source of URIs and authoritative names for people and organisations
> >>>> (compiled and managed by the bibliographic community but used widely)
> is
> >>>> already in SKOS.  SKOS is also used in many other domains.
> >>>>
> >>>> I could see this adding value without significant impact on the rest
> of
> >>>> Schema.
> >>>>
> >>>> What do others think?
> >>>
> >>> I've been thinking in this direction too (and had brief discussion
> >>> with Jamie, cc:'d, w.r.t. Freebase's approach).
> >>>
> >>> SKOS has done well and a great many controlled vocabularies in the
> >>> thesauri, subject classification and code list tradition are expressed
> >>> using it. SKOS handles various cases where 'class/object/property'
> >>> models don't capture things well. I'd like to have a way of reflecting
> >>> SKOS-oriented data into schema.org descriptions without going
> >>> 'multi-namespace'. There are also already various corners of
> >>> schema.org where different loose notions of 'category' are slipping
> >>> in.
> >>>
> >>> My current preference would be to call a new type "Topic" or perhaps
> >>> "Category" rather than the more esoteric / vague "Concept", even while
> >>> borrowing most structure and terminology from SKOS.
> >>>
> >>> Do you have a strawman list of what you'd hope to include, from a
> >>> bibliographic perspective?
> >>>
> >>> Dan
> >>>
> >>>> ~Richard
> >>>>
> >>>> --
> >>>> Richard Wallis
> >>>> Technology Evangelist
> >>>> OCLC
> >>>>
> >>>>
> >>>>
> >>>> [1] http://www.w3.org/community/schemabibex/
> >>>> [2] http://www.w3.org/TR/skos-reference/
> >>>> [3] http://www.w3.org/wiki/WebSchemas/ExternalEnumerations
> >>>> [4] http://id.loc.gov/authorities/subjects.html
> >>>>
> >>>
> >>
> >> --------------------------------------------------------
> >> martin hepp
> >> e-business & web science research group
> >> universitaet der bundeswehr muenchen
> >>
> >> e-mail:  hepp@ebusiness-unibw.org
> >> phone:   +49-(0)89-6004-4217
> >> fax:     +49-(0)89-6004-4620
> >> www:     http://www.unibw.de/ebusiness/ (group)
> >>        http://www.heppnetz.de/ (personal)
> >> skype:   mfhepp
> >> twitter: mfhepp
> >>
> >> Check out GoodRelations for E-Commerce on the Web of Linked Data!
> >> =================================================================
> >> * Project Main Page: http://purl.org/goodrelations/
> >>
> >>
> >>
> >>
> >
> >
> > ----
> > Ivan Herman, W3C Semantic Web Activity Lead
> > Home: http://www.w3.org/People/Ivan/
> > mobile: +31-641044153
> > FOAF: http://www.ivan-herman.net/foaf.rdf
> >
> >
> >
> >
> >
>
> --------------------------------------------------------
> martin hepp
> e-business & web science research group
> universitaet der bundeswehr muenchen
>
> e-mail:  hepp@ebusiness-unibw.org
> phone:   +49-(0)89-6004-4217
> fax:     +49-(0)89-6004-4620
> www:     http://www.unibw.de/ebusiness/ (group)
>          http://www.heppnetz.de/ (personal)
> skype:   mfhepp
> twitter: mfhepp
>
> Check out GoodRelations for E-Commerce on the Web of Linked Data!
> =================================================================
> * Project Main Page: http://purl.org/goodrelations/
>
>
>
>
>


-- 
*Bernard Vatant
*
Vocabularies & Data Engineering
Tel :  + 33 (0)9 71 48 84 59
Skype : bernard.vatant
Blog : the wheel and the hub <http://blog.hubjects.com/>

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Received on Thursday, 10 January 2013 23:05:55 GMT

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