- From: Osma Suominen <osma.suominen@helsinki.fi>
- Date: Wed, 16 Sep 2015 21:13:22 +0300
- To: public-esw-thes@w3.org
Dear Juan,
I am very sorry for my unclear brief comments. I didn't mean that you
wanted to introduce changes to SKOS, and certainly didn't intend to
restrict you from creating and publishing UNESKOS. Rather, my thoughts
are along these lines:
1. Having an inverse property for {skos:inScheme,skos:member} has
nothing to do with the *content* of the UNESCO Thesaurus. In my
impression, the content in the UNESCO Thesaurus very closely follows
standards and best practices. The only slightly special aspect in UNESCO
Thesaurus that I'm aware of is the use of microthesauri, but that is not
relevant for this discussion, at least not for the above mentioned SKOS
properties.
2. Thus, if there is a good reason for introducing such properties, that
reason should equally apply to all SKOS datasets, or at least many of them.
3. Therefore, if such properties are introduced, a good place to define
them would be SKOS itself, or a general purpose SKOS extension similar
to iso-thes or perhaps the GVP extensions to SKOS. Not a
thesaurus-specific vocabulary such as UNESKOS.
Armando already explained that there may be good reasons why such
properties were not defined by SKOS itself. In some cases it simply
makes sense to keep the model simpler by not introducing many
properties. There are also practical concerns like Armando mentioned -
for example, DESCRIBE queries returning way too much data, or having to
generate RDFa markup for tens of thousands of concepts on the HTML page
of the concept scheme. These may or may not apply in your specific case.
Perhaps the benefit of forward direction properties outweighs the
potential pitfalls.
You mentioned that getting from the ConceptScheme to, e.g.,
microthesauri represented by ConceptGroup, is impossible, because of the
inverse property between these. But this assumes that you can only
follow properties from subject to object. Why this restriction?
Obviously CBD is defined in such a way, but Linked Data representations
can equally well serve Symmetric Concise Bounded Descriptions (and often
do), or use another subset definition that includes statements also in
the inverse direction.
As I said you are of course free to define and use your own properties
as you like and, as you noted, your usage is fully compliant with SKOS
and users may simply ignore your extensions and still get all the
information from the SKOS properties. By the way, it is excellent that
you have made such good documentation for UNESKOS, so that it is
possible to have this discussion!
Also, congratulations on the new release of the UNESCO Thesaurus! I've
played with the earlier version, and also put it up on the Skosmos demo
site here: http://skosmos.dev.finto.fi/unesco/en/
(I expect to update the demo installation to the upcoming Skosmos 1.2
release in the near future, then the microthesauri/groups could also be
displayed and browsed!)
The UNESCO Thesaurus has been exemplary in itse use of SKOS and RDF. In
my previous research I've looked at the data quality of many SKOS
datasets, and the UNESCO Thesaurus was one of the very best!
Best regards
Osma
16.09.2015, 15:28, Juan Antonio Pastor Sánchez kirjoitti:
> Dears Armando and Osma
>
> Thank you very much for your observations.
>
> Osma, sorry, but we don't want to change anything about SKOS. We don't
> require any SKOS changes. I don't know the reason why you say that. Can
> you explain me? The UNESKOS vocabulary refers to an vocabulary for and
> specific case that can be used for others thant find useful our work.
> *Your affirmation that we want to change SKOS is absolutely false.* Our
> work complements SKOS, but doesn't replace it. SKOS should continue as
> is to remain SIMPLE as you think.
>
> I think that define a specific vocabulary that *complements* SKOS and
> ISO-THES is not forbidden (as far as I remember) and this restriction is
> a kind of dogmatism that goes against the very essence of the Semantic
> Web. And I don't like it.
>
> UNESKOS is designed to complement SKOS and ISO-THES. It isn't an
> alternative. If fact, if you get the SKOS dataset for the UNESCO
> Thesaurus and ignore all the statements that have any UNESKOS property
> the SKOS representations is acording to SKOS and ISO-THES. Certainly,
> the dataset have been tested with Skosify.
>
> The question is: Really, it's necessary a vocabulary that define
> inverses for several SKOS properties?
>
> In my opinion, we must not forget that Linked Data remains the Web and I
> think that the Information Architecture principles for SKOS dataset are
> applicable (and useful). Please, as we note in the reference document:
> don't think that a SPARQL Endpoint it's always avalaible.
>
> Think in the home page of a web site that no have links to continue the
> navigation to the inside contents. The lack the properties from the
> Concept Schemes to the Concept Groups (that are intended for represent
> micro-thesaurus) is the same.
>
> Please take a wider view and *don't think only in terms of SPARQL*,
> think in terms of information architecture of the dataset so that it can
> be reused in other ways to increase interoperability.
>
> So, please, think about a scenario in which you don't have an SPARQL
> Endpoint to query the dataset. An example for this: the HTML version of
> a vocabulary with RDFa markup that include the RDF statements of the
> SKOS dataset into the HTML markup. The Concise Bound Description doesn't
> useful in this case because implies needless and artificial HTML code.
>
> One case: From a iso-thes:ConceptGroup (or micro-thesaurus): How can we
> reach to the top concepts without using SPARQL and applying the
> SKOS/ISO-THES properties only?
>
> In one word: impossible. So this is the meaning of
> uneskos:hasMainConcept and uneskos:mainConceptOf: Access points to
> continue (or start) to navigate the hierarchical structure of the thesaurus.
>
> Even more: How can we reach from skos:ConceptScheme to
> iso-thes:ConcepGroup. Impossible, because iso-thes:microThesaurusOf goes
> on inverse way. So this is the meaning of uneskos:hasMicroThesaurus.
>
> The uneskos:memberOf solves the discovery of the Collection/ConceptGroup
> to which a concept belong without use SPARQL.
>
> Repect uneskos:contains. Well, with a depply reading of the reference
> document you can find:
>
> NOTE: It is not necessary the inclusion of uneskos:contains property
> between the Concept Schemes and the Concepts in the SKOS dataset. In the
> context of a well designed KOS, it is possible to find a path to any
> Concept of the KOS starting from the Concept Scheme and the Top
> Concepts. However, SKOS does not provide any element to discover (i.e.)
> the Collections of a KOS from the Concept Scheme. The property
> uneskos:contains covers this need.
>
> This is because the first SKOS version of the UNESCO Thesaurus includes
> statement like this:
>
> <Collection> skos:inScheme <Concept_Scheme>
>
> And the uneskos:contains property is intended for:
>
> <Concept_Scheme> skos:contains <Collection>
>
> Best regards,
> Juan
>
>
> 2015-09-16 13:36 GMT+02:00 Osma Suominen <osma.suominen@helsinki.fi
> <mailto:osma.suominen@helsinki.fi>>:
>
> Hi Juan!
>
> My first reaction was the same as Armando's 2nd point, i.e. some of
> your extensions (namely unesco:contains and unesco:memberOf) are
> extensions of core SKOS with no inherent relationship to the UNESCO
> Thesaurus.
>
> There are certainly arguments about whether properties should be
> defined in both directions or not. In this case SKOS has decided to
> make only one way relationships (at least in these two cases,
> skos:inScheme and skos:member) and you now want to change that by
> introducing the inverse properties as well. You can certainly do
> that for your own thesaurus but I think that sticking to the SKOS
> properties would be simpler for everyone. In SPARQL and most RDF
> toolkits it is not very difficult to follow property paths in either
> direction.
>
> -Osma
>
>
>
> On 16/09/15 11:57, Armando Stellato wrote:
>
> Dear Juan,
>
> just a couple of notes.
>
> 1.Why the word “main” adopted in some property names? I don’t
> find any
> rationale for the use of “main” as the concepts do not seem to
> be “main”
> at all for the related schemes/collections.
>
> 2.Some properties, more than being targeted at a special domain
> (e.g.
> UNESCO), seems plain extensions of the core SKOS, aiming at
> filling some
> gaps left by it. However in some cases I feel like these gaps
> were left
> by purpose. E.g. the uneskos:contains provides an inverse
> property for
> skos:inScheme. Think about a 30.000 concepts thesaurus (for
> which there
> exists at least a scheme containing all concepts). If you were
> using the
> UNESKOS vocabulary, you surely would try a SPARQL DESCRIBE on
> this main
> scheme? ;-)
>
> a.Use of SPARQL (or -1 expressions in DL) does not strictly
> require for
> the presence of named inverse properties for everything. So, why
> do they
> exist? Because when you get the description (for example by a
> DESCRIBE,
> but not limited to that) of a resource, they can provide nice
> “resumes”
> for it. The kind of path you want to realize (see the description of
> hasMainConcept) can be performed without the strict need of the
> property. It is up to SKOS browsing tools to allow for that
> visualization/traversal options.
>
> Just my two cents on that,
>
> Best regards,
>
> Armando
>
> *Da:*Juan Antonio Pastor Sánchez [mailto:pastor@um.es
> <mailto:pastor@um.es>]
> *Inviato:* mercoledì 16 settembre 2015 02:21
> *A:* public-esw-thes@w3.org <mailto:public-esw-thes@w3.org>
> *Oggetto:* UNESKOS Vocabulary and 2nd SKOS version of UNESCO
> Thesaurus
>
> Dear all,
>
> I want to communicate the publication Vocabulary UNESKOS that
> complements certain aspects of SKOS [1] and ISO-THES [2]. This
> vocabulary is designed in the context of the proposed UNESKOS, more
> specifically for the SKOS representation of the UNESCO Thesaurus.
>
> The document describing the vocabulary is available at:
>
> * http://skos.um.es/TR/uneskos
>
> The RDF vocabulary is available for download and use from the
> UNESKOS
> namespace:
>
> * http://purl.org/umu/uneskos# <http://purl.org/umu/uneskos>
>
> Likewise, the 2nd SKOS version of the UNESCO Thesaurus is
> available at:
>
> * http://skos.um.es/unescothes
>
> Includes following features:
>
> * Persistent and Dereferenceable URIs.
> * Turtle and RDF/XML Datasets avalaible for download.
> * RDFa markup.
> * SPARQL Endpoint.
> * Content negotiation avalaible in N3, JSON-LD, etc...
>
> This second version makes use of SKOS, ISO-THES and UNESKOS.
> Along the
> coming weeks new features navigation within the HTML version
> will be added.
>
> Please, for any suggestion or correction you can contact me.
>
> Best regards,
>
> Juan
>
> --
>
> Juan Antonio Pastor Sánchez, Ph.D.
> Dep. of Information and Documentation
> Faculty of Communication and Documentation
> University of Murcia
> phone: +34 868 88 7252 <tel:%2B34%20868%2088%207252>
> http://webs.um.es/pastor
> pastor@um.es <mailto:pastor@um.es> <mailto:pastor@um.es
> <mailto:pastor@um.es>>
>
>
>
> --
> Osma Suominen
> D.Sc. (Tech), Information Systems Specialist
> National Library of Finland
> P.O. Box 26 (Kaikukatu 4)
> 00014 HELSINGIN YLIOPISTO
> Tel. +358 50 3199529 <tel:%2B358%2050%203199529>
> osma.suominen@helsinki.fi <mailto:osma.suominen@helsinki.fi>
> http://www.nationallibrary.fi
>
>
>
>
> --
> Dr. Juan Antonio Pastor Sánchez
> Dep. de Información y Documentación
> Facultad de Comunicación y Documentación
> Universidad de Murcia
> Tel: +34 868 88 7252
> http://webs.um.es/pastor
> pastor@um.es <mailto:pastor@um.es>
>
> Juan Antonio Pastor Sánchez, Ph.D.
> Dep. of Information and Documentation
> Faculty of Communication and Documentation
> University of Murcia
> phone: +34 868 88 7252
> http://webs.um.es/pastor
> pastor@um.es <mailto:pastor@um.es>
--
Osma Suominen
D.Sc. (Tech), Information Systems Specialist
National Library of Finland
P.O. Box 26 (Kaikukatu 4)
00014 HELSINGIN YLIOPISTO
Tel. +358 50 3199529
osma.suominen@helsinki.fi
http://www.nationallibrary.fi
Received on Wednesday, 16 September 2015 18:13:57 UTC