W3C home > Mailing lists > Public > public-vocabs@w3.org > June 2014

RE: How do you flag a resource which is not available anymore?

From: Young,Jeff (OR) <jyoung@oclc.org>
Date: Mon, 2 Jun 2014 14:29:43 +0000
To: Bernard Vatant <bernard.vatant@mondeca.com>, Quentin Reul <Quentin.H.Reul@gmail.com>
CC: Simon Spero <sesuncedu@gmail.com>, "public-vocabs@w3.org" <public-vocabs@w3.org>
Message-ID: <2c5286767c3342d3b72f7fa71e7b8fb3@BY2PR06MB204.namprd06.prod.outlook.com>
As I understood owl:deprecated, OWL (2004) originally defined defind owl:DeprecatedClass and owl:DeprecatedProperty, which as Bernard suggest are limited to vocabulary terms. The typical case was to use owl:equivalentClass or owl:equivalentProperty (rather than dcterms:isReplacedBy) to map the deprecated terms to their replacement(s), if any:

http://www.w3.org/TR/owl-ref/#Deprecation


The owl:deprecation property appears to have been added in OWL 2 (2012):

http://www.w3.org/TR/owl2-quick-reference/#Additional_Vocabulary_in_OWL_2_RDF_Syntax


Unlike the OWL 2004 terms, the rdfs:domain on owl:deprecated is rdfs:Resource implies that the deprecation concept could be broadened to apply to any resource, not just classes and properties.

It’s never been clear to me, though, whether this means the IRI is deprecated (e.g. as in the sense of using owl:sameAs to point at a more stable URI) or whether it is the entity that is being deprecated (in the sense of being marked obsolete or mistaken):


·         IRI is deprecated?: http://www.w3.org/TR/2012/REC-owl2-syntax-20121211/#a_deprecated


o   “An annotation with the owl:deprecated annotation property and the value equal to "true"^^xsd:boolean can be used to specify that an IRI is deprecated.”

·         Entity is deprecated?: http://www.w3.org/2002/07/owl#deprecated:


o   owl:deprecated a owl:AnnotationProperty ;
     rdfs:label "deprecated" ;
     rdfs:comment "The annotation property that indicates that a given entity has been deprecated." ;
     rdfs:domain rdfs:Resource ;
     rdfs:isDefinedBy <http://www.w3.org/2002/07/owl#> ;
     rdfs:range rdfs:Resource .

I’m guessing it’s the IRI that’s deprecated. The reason for deprecating it could be explained in an rdfs:comment.

Jeff

From: Bernard Vatant [mailto:bernard.vatant@mondeca.com]
Sent: Monday, June 02, 2014 9:22 AM
To: Quentin Reul
Cc: Simon Spero; public-vocabs@w3.org
Subject: Re: How do you flag a resource which is not available anymore?

Hi Quentin
The way I understood it, owl:deprecated is more designed to mark elements in a vocabulary as deprecated, but not the entire vocabulary. Moreover, owl:deprecated should be used in a controlled versioning workflow, by the vocabulary publisher herself, and in the best of worlds, it goes with a dcterms:isReplacedBy (but as said above, this is not unfortunately a very frequent practice).
Here we deal with URIs which just disappear "puff" in a smoke like URIs do, by neglect of their owner, hosting not paid, site reorganization whatever.
And we have to make this observation and declaration from outside : the resource we are speaking about used to live at this URI, but for some non documented reason it's not there anymore.

2014-06-02 14:45 GMT+02:00 Quentin Reul <Quentin.H.Reul@gmail.com<mailto:Quentin.H.Reul@gmail.com>>:
Hi all,

It may be a bit too simplistic, but OWL2 defines a property (owl:deprecated [1]) to mark any entities (classes, properties and instances) as deprecated. The range of the property is xsd:boolean. Would this not be sufficient for your needs?

Kind regards,

Quentin Reul

[1] http://www.w3.org/TR/2012/REC-owl2-syntax-20121211/#a_deprecated


On 2 June 2014 03:17, Bernard Vatant <bernard.vatant@mondeca.com<mailto:bernard.vatant@mondeca.com>> wrote:
Simon
Thanks for the reference, not yet looked into it in details, but as answered to Ed, we're not looking for an overkill solution :)

2014-05-30 23:13 GMT+02:00 Simon Spero <sesuncedu@gmail.com<mailto:sesuncedu@gmail.com>>:

This paper is generally relevant to the semantics, though it doesn't solve the specific problem:

Representing and Querying Validity Time in RDF and OWL: A Logic-Based Approach✩
Boris Motik, Oxford University Computing Laboratory, Oxford, UK

 http://www.cs.ox.ac.uk/boris.motik/pubs/m12validity-time.pdf


PROV-O can handle the use case, but has the downside of being PROV-O, and requiring a few blank nodes (validity is a bit fuzzy).

http://www.w3.org/TR/2013/REC-prov-o-20130430/#invalidatedAtTime

http://www.w3.org/TR/2013/REC-prov-o-20130430/#Revision


Also, note that the ontology named by a version IRI is fixed;  if the IRI becomes impossible to dereference, the cached content should always be valid;  however, this may not be the case if the base IRI is used.

Indeed! But the use of versionIRI in LOV vocabularies is not a general practice, far from it : See http://bit.ly/1nH1vlq

Less than 10% of vocabularies have a owl:versionIRI declaration, and those who use it don't always do it correctly :(
More generally the versioning policy is globally a mess ... See http://bit.ly/RWoZUu

Very often there is no version number or date whatsoever, or they are not consistent between the documentation and RDF files (you can have one date in the html, another in the RDF/XML file, and yet another one in the Turtle ...

The contents of the LOV-back-machine is as valid as it ever was.
 It is possible that an unversioned ontology  might have changed between the last capture and the 404

This should not happen if the LOV-Bot, which is tracking changes on a daily basis, does its job properly. But due to content negotiation issues and dozens of other reasons, it is not always the case. And very small changes like corrections of typos can induce the LOV-Bot into uploading of a new version, althogh the formal version information has not changed.
But those are known issues that I would not want to blur the simple question at hand : simply providing the information that this URI used to be dereferenceable, but is currently no more, so if you use this vocabulary in your data, the semantics will not be found through the vocabulary URI, but through some version backup etc. We are in terra incognita there ...
Bernard


On Fri, May 30, 2014 at 5:09 AM, Bernard Vatant <bernard.vatant@mondeca.com<mailto:bernard.vatant@mondeca.com>> wrote:
Hi vocabulers
We have more and more records in LOV of which URIs are 404, unfortunately, with no replacing resource whatsoever.
See e.g., http://lov.okfn.org/dataset/lov/details/vocabulary_dir.html etc
We want to keep the record in LOV, along with backup versions, such as
http://lov.okfn.org/dataset/lov/agg/archives/dir_dir/file_dir_2006-06-27.n3

We want to flag the URI some way, such as some "offlineSince" or "validUntil" property, with value a xsd:date. This property would be added to the VOAF vocabulary, unless someone knows about an existing property to express that. There are various "valid" properties in DC terms and other vocabularies, but not sure they capture the expected semantics.
Thanks for any suggestion.

--
Bernard Vatant
Vocabularies & Data Engineering
Tel :  + 33 (0)9 71 48 84 59
Skype : bernard.vatant
http://google.com/+BernardVatant

--------------------------------------------------------
Mondeca
35 boulevard de Strasbourg 75010 Paris
www.mondeca.com<http://www.mondeca.com/>
Follow us on Twitter : @mondecanews<http://twitter.com/#%21/mondecanews>
----------------------------------------------------------




--
Bernard Vatant
Vocabularies & Data Engineering
Tel :  + 33 (0)9 71 48 84 59
Skype : bernard.vatant
http://google.com/+BernardVatant

--------------------------------------------------------
Mondeca
35 boulevard de Strasbourg 75010 Paris
www.mondeca.com<http://www.mondeca.com/>
Follow us on Twitter : @mondecanews<http://twitter.com/#%21/mondecanews>
----------------------------------------------------------




--
Bernard Vatant
Vocabularies & Data Engineering
Tel :  + 33 (0)9 71 48 84 59
Skype : bernard.vatant
http://google.com/+BernardVatant

--------------------------------------------------------
Mondeca
35 boulevard de Strasbourg 75010 Paris
www.mondeca.com<http://www.mondeca.com/>
Follow us on Twitter : @mondecanews<http://twitter.com/#%21/mondecanews>
----------------------------------------------------------
Received on Monday, 2 June 2014 14:40:51 UTC

This archive was generated by hypermail 2.3.1 : Tuesday, 6 January 2015 21:29:42 UTC