RE: comment: WD 10 May 2005

John

I've no bandwidth now to address the details of your message below. I'm sure the SKOS
editors, Alistair and Dan, who seem to be in some kind of vacation right now, will jump in
the thread as soon are they are available again.

I just want to stress the historical and community background of SKOS.

"SKOS is an area of work developing specifications and standards to support the use of
knowledge organisation systems (KOS) such as thesauri, classification schemes, subject
heading lists, taxonomies, terminologies, glossaries and other types of controlled
vocabulary within the framework of the semantic web."

SKOS does not come out of the blue. It leverages the legacy of a community of librarians,
vocabulary managers, etc. who have developed over years their own terminology, ways of
working and thinking. Their own paradigm, if you like big words. People in this area don't
use, and are not familiar at all with, formal logic and AI legacy which underlies the SW
RDF/RDFS/OWL family of standards. Speaking about classes, instances and properties make
those people uneasy, the same way the way they deal with concepts, subjects, descriptors,
terms, broader-narrower relationships and the like seems to make you uneasy.

All the point of SKOS is to make this legacy usable in the SW framework, without loss of
its specificity, and without forcing, so to speak, librarians and thesaurus folks to give
up their paradigm and tools. There is no reason why they should do so anyway. Formal logic
legacy/community and librarian legacy/community (and many more, like linguistics,
psychology, cognitive science, unameit) have to live together and enrich each other, not
to go at war to try to impose their paradigm on each other, as we have unfortunately seen
so many times in the past (and still see).

Seems to me that SKOS makes a good job in that respect, in the sense that the editors have
make a good deal of efforts to understand the legacy, and the legacy folks have brought
very useful insights on the development of the specification. I've always been very
appreciative of the quality of this difficult but always constructive dialogue between
communities in this forum. The current state of SKOS is the result of this process, seems
to me it's a very good consensus. And as a consensus, it contains bits and pieces some
people are particularly happy with, because it's their stuff, and some pieces they have
not completely adopted yet.

Making a standard is 10% engineering, 90% diplomacy :))

Regards

----------------------------------
Bernard Vatant
Mondeca Knowledge Engineering
bernard.vatant@mondeca.com
(+33) 0871 488 459

http://www.mondeca.com
http://universimmedia.blogspot.com
----------------------------------

> -----Message d'origine-----
> De : public-esw-thes-request@w3.org
> [mailto:public-esw-thes-request@w3.org]De la part de John McClure
> Envoyé : jeudi 21 juillet 2005 02:11
> À : Bernard Vatant; public-esw-thes@w3.org
> Objet : RE: comment: WD 10 May 2005
>
>
>
> Bernard,
> Thank you for the reply. I don't deny the need for a class like Concept. I guess
> that I'm disturbed by your implementation. One use case I think of categorizes
> resources by the terms defined within an ontology. Under SKOS, the whole
> ontology seems duplicated so that each resource's <dc:Subject> value can
> reference an instance of Concept rather than directly referencing a class
> defined in the ontology.
>
> CONCEPT DEFINITION. What is "a term in a controlled vocabulary" (your words) if
> not an rdfs:Class -- this is not asked rhetorically at all. Perhaps your
> definition of a Concept is revealed when you say with regard to FreedomOfSpeech
> that "I am quite reluctant to consider this concept as a class, because I wonder
> what the instances would be" -- this suggest your definition is that anything
> that is difficult to envision as an instance, is therefore a Concept. [BTW,
> consider a "FreedomOfSpeech" resource as an item in an inventory of rights had
> by an individual.]
>
> My alternative view is that a 'concept' is a document-related class of resources
> distinguishable by a Reasoner from the classes of terms defined within an
> ontology being used by or specified within the document. Resources can be
> categorized as being 'of' a concept either by a property, eg <dc:Subject>, or by
> an <rdf:type> element which specifies the Concept instance. Conversely, the
> 'isSubjectOf' property should most definitely be applicable to instances of
> owl:Class (and to its subclass, Concept), referring to those resources
> categorized as being 'of' the concept.
>
> TOPIC RELATION. I see no conceptual semantic difference, and little has been
> offered, between a concept and a topic. My view is that every concept IS a
> topic; every topic is a concept. A topic (or concept) refers conceptually either
> to (a) a set of generic or specific instances or (b) a specific instance, about
> which statements are made or, said another way, which are the subject matter of
> ensuing statements. Due to (a), I claim that topics are normally plural terms;
> those infrequent times they are singular, means that the topic of the text unit
> is a specific resource.
>
> An ontology class can be referenced in a ConceptSchema as a Concept that is
> either a reified statement about the class, or one whose subject is the ontology
> class. In this way class instances can be referenced in a topic map as easily as
> new topics (or concepts) can be defined. Likewise, a topic or concept that is
> about another topic or concept, is a reified statement or (if you prefer) one
> whose subject is the other topic or concept.
>
> Lastly, and perhaps this is better left for later, I see little difference
> between a 'category' and a concept, topic, or class -- in my own ontology I use
> the metaclass 'Category' because it seems more user-friendly. Its Word Net
> definition is "A general concept that marks divisions or coordinations in a
> conceptual scheme. A collection of things sharing a common attribute."
>
> OTHER SKOS CLASSES. I see no problem making skos:ConceptSchema (or TopicMap) a
> subclass of Ontology. A skos:Collection looks all the world like an anonymous
> class (which can have its own rdfs:label BTW) and which is composed of a unionOf
> (with its parseType =Collection incidentally) with its sub-concepts (or
> sub-topics or sub-classes) then listed. Can OrderedCollection be accommodated by
> a different parseType?
>
> SKOS PROPERTIES. If a Concept is a metaclass (that is, whose instances are also
> instances of owl:Class), there are implications for the properties defined for
> Concept. For instance, while the 'broader' property appears directly equivalent
> to rdfs:subClassOf, the 'narrower' property is not formally accommodated. Child
> concept/topic resources certainly are narrowed concepts/topics in accordance to
> the definition of a 'subclass'.
>
> I haven't time now to analyze other SKOS properties... Bottom-line, the SKOS
> data model remains ambiguous to me so I would much appreciate it if SKOS could
> make a rigorous distinction between a class, topic, concept, subject, and
> category -- to help practitioners like myself understand best practices on the
> Semantic Web.
>
> Oh, as for "table of contents" -- I can't find it now! Thought it was there....
> sorry for the noise about that.
>
> Best regards,
> John McClure
>
>

Received on Thursday, 21 July 2005 08:25:38 UTC