Re: Importing SKOS model in ontology editors : clash with annotation properties

Hi Johannes

Your viewpoint is indeed very interesting.  Maybe the "semantic 
skeleton" you are asking for is defined at
http://www.w3.org/2006/07/SWD/SKOS/reference/20081001/skos-dl.rdf
I discovered it while browsing this list archive, but surprisingly 
enough, even the SKOS editors themeselves do not seem to be quite clear 
about the satus of this model, which is, as the URI suggests, OWL-DL.
See e.g., Antoine Isaac answer to Thomas Baker about it at
http://lists.w3.org/Archives/Public/public-swd-wg/2009Mar/0054.html

As an aside, I had a similar issue with the Geonames ontology. In the 
first version of it, I wanted to stick to OWL-DL and even OWL-Lite, but  
some people including Tim Berners-Lee himself insisted that the labeling 
attributes such as geonames:name, geonames:alternateName and 
geonames:officialName should be subproperties of rdfs:label, in order 
for RDF tools such as Tabulator to use them for display purposes. The 
solution adopted (I can't remember the original author of this proposal 
now, unfortunately) was to have an OWL-Lite version without this 
subproperties assertions, and an OWL-Full version importing the OWL-Lite 
version and just adding the subproperties assertions.
See http://www.geonames.org/ontology/ontology_v2.0_Full.rdf

Seems to me that could be done for SKOS model in asimilar way, making 
everybody happy. The subproperties assertions have to be there for 
search engines such as Sindice, RDF browsers such as Tabulator, while 
reasoners could get rid of them and stick to the DL model, being more 
interested in semantic relationships between concepts.

Bernard

> Dear SKOS editors,
>
>
> (my personal view:)
>
> I'm working at a little company, which provides a nice and fast 
> ontology language (called F-logic, which is sort of a enhanced 
> datalog). We also have an own OWL reasoner implementation (which does 
> OWL DL A-Box inferencing pretty fast). And of course we have an 
> ontolog engineering environment (called OntoStudio) which allows for 
> an (as far this is possible) integrated view on F-logic and OWL.
>
> The industrial customers of our semantic technologies want to be sure 
> that we provide inferencing which is sound and complete. They 
> explicitely require that we do not apply "semantic heuristics" which 
> are not well defined. This means that from a contractual point of view 
> we are not allowed to prune a 3rd party OWL full ontology into an OWL 
> DL (or OWL2 EL, OWL2 R etc) ontology.
>
> After long discussions we have decided *not* to support even *loading* 
> OWL full ontologies into our systems. Why? While we of course often 
> can *guess* which parts of an OWL full ontology are there mainly in 
> order to communicate the understanding of an ontology (as opposed to 
> do inferencing with it) we do not *know* that for sure. I.e. we cannot 
> prove that a specific semantic model for our customer is at least 
> correct when there was an OWL full ontology in the chain.
>
> As a result we cannot use the skos2008 version as it is. As long as 
> there is only an OWL full version of SKOS this standard remains 
> academic. We simply stick to skos2004 until things get better.
>
> I understand that things will become much better when OWL2 is 
> finished. (But please give us some time and resources to implement 
> OWL2 then; it's pretty complex).
>
> For the time being I'd like to ask whether it is possible for you to 
> provide a "semantic skeleton" of skos2008, which has to be sound and 
> complete, but neverttheless equivalent to your intended semantics of 
> skos 2008.
>
> This is something which has to be done by the authors themself, 
> because we are speaking here of standards and intentions. This also 
> would help to communicate the very core of the skos idea in a simple way.
>
>
> yours
> Johannes
>
>
> PS: Using skos 2008 (i.e. integrating it with other ontolgies) 
> additionally would be even more interesting if the semantic skeleton 
> of skos2008 would prove to be OWL1 ultralite, OWL2 EL, OWL2 RL or any 
> other *fast and simple* OWL2 profile. (Even OWL DL ist to complex to 
> allow for large scale inferencing.) Then skos would in faxt remain a 
> simple KOS, which could in fact act as a very nice, lightweight and 
> powerful (1) stand alone starting point and (2) extension to many 
> other ontology projects.
>
>
>
> Bernard Vatant wrote:
>> Hello
>>
>> I'm not sure SKOS editors were aware of the behavior of various OWL 
>> ontology editors regarding the handling of the annotation properties 
>> (labels and documentation) in the current SKOS model.
>> To declare rdfs:subPropertyOf relationships between annotation 
>> properties is definitely a OWL-Full feature at least in OWL 1.0. I 
>> can read in the reference document that this feature "makes SKOS more 
>> usable with the OWL 2 specification currently in development". Not 
>> sure about what will come out of OWL 2.0, but when using OWL 1.0 
>> ontology editors, this situation leads to various inconsistent 
>> behaviours. Basically they do not support this kind of construction, 
>> and they get rid of it in different ways.
>>
>> Examples:
>>
>> SWOOP 2.3 latest (and last) release - I know this one is a bit old 
>> and no more under development, but I keep using it default of better 
>> free lightweight tool.
>> The rdfs:subProperty relationships between annotation properties are 
>> simply ignored, and if you save the model, they are definitely off.
>>
>> Protégé 4.0 decides that "pure" annotation properties can't be the 
>> subject of assertions, so it considers all the annotation properties 
>> participating in the subproperty statements are object properties 
>> (but still annotation properties), which seems weird to me. There 
>> again, if the model is saved, properties are saved this way.
>>
>> Remarkably enough, none of those tools signal any error or trigger 
>> any warning when loading the file. Which is unfortunate indeed.
>> It's been a daily routine in Mondeca to merge the SKOS model into 
>> wider customer ontologies we manage with the above editors.
>> And I guess we are not alone in this case.
>>
>> I have no solid proposal to deal with that issue, but just wondering 
>> if others have stumbled on it.
>>
>> Cheers
>>
>> Bernard
>>
>
>


-- 

*Bernard Vatant
*Senior Consultant
Vocabulary & Data Engineering
Tel:       +33 (0) 971 488 459
Mail:     bernard.vatant@mondeca.com <mailto:bernard.vatant@mondeca.com>
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Received on Wednesday, 25 March 2009 08:54:43 UTC