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RE: [Proposal] SKOS-Core Schema Management and Evolution

From: Miles, AJ (Alistair) <A.J.Miles@rl.ac.uk>
Date: Mon, 26 Jul 2004 17:13:21 +0100
Message-ID: <350DC7048372D31197F200902773DF4C05E50B45@exchange11.rl.ac.uk>
To: 'Dan Brickley' <danbri@w3.org>
Cc: "'public-esw-thes@w3.org'" <public-esw-thes@w3.org>

Thanks Dan, I was hoping you would chip in on this one, given your wisdom on
the subject :)

In section 3, perhaps I should have used ...

         <owl:DeprecatedClass rdf:ID="ExampleOldClass">
			<owl:versionInfo>This class is now deprecated.  Use
the 'ExampleNewClass' class instead.</owl:versionInfo> 
         </owl:DeprecatedClass> 

... as an example of how I propose to handle deprecation.

Dan, your comment ...

> Hmm, depends if Concepts are Classes, though?

... was this a comment on the general way of doing deprecation using OWL, or
on the specific (hypothetical) deprecation that was used as an example?

Al.

---
Alistair Miles
Research Associate
CCLRC - Rutherford Appleton Laboratory
Building R1 Room 1.60
Fermi Avenue
Chilton
Didcot
Oxfordshire OX11 0QX
United Kingdom
Email:        a.j.miles@rl.ac.uk
Tel: +44 (0)1235 445440



> -----Original Message-----
> From: public-esw-thes-request@w3.org
> [mailto:public-esw-thes-request@w3.org]On Behalf Of Dan Brickley
> Sent: 26 July 2004 16:51
> To: Miles, AJ (Alistair) 
> Cc: 'public-esw-thes@w3.org'
> Subject: Re: [Proposal] SKOS-Core Schema Management and Evolution
> 
> 
> 
> * Miles, AJ (Alistair)  <A.J.Miles@rl.ac.uk> [2004-07-26 16:40+0100]
> > 
> > To cope with evolution and change of the SKOS-Core RDF 
> schema over both the
> > current development iteration and the longer term, I 
> propose the following:
> > 
> > [N.B. these proposals are a copy of the
> > http://esw.w3.org/topic/SkosDev_2fSchemaManagement wiki 
> page as it stood at
> > the time of writing].
> > 
> > 
> > 1: Namespace Management
> > 
> > Currently the SKOS-Core RDF schema resides under the namespace
> > <http://www.w3.org/2004/02/skos/core#>. 
> > 
> > It is proposed that there be no short or medium term 
> versioning of this
> > schema using different namespaces ... i.e. the terms of the 
> schema will be
> > maintained under the current namespace for the forseeable future. 
> 
> +1 (keeping a common namespace and evolving it in place, when 
> done with
> care, imho works better than changing (based on Dublin Core and FOAF
> experience))
> > 
> > 
> > 2: Term Status Management
> > 
> > To manage the status of SKOS-Core RDF schema it is proposed 
> that the Vocab
> > Status RDF schema 
> <http://www.w3.org/2003/06/sw-vocab-status/ns#> is used.
> > ... This involves assigning every SKOS class and property a 
> 'term_status'
> > value, which is formally expressed as part of the schema. 
> > 
> > For example ... 
> > 
> >         <rdfs:Class rdf:ID="ConceptScheme"> 
> >                 <rdfs:label>Concept Scheme</rdfs:label> 
> >                 <rdfs:comment>A concept scheme is a collection of
> > concepts.</rdfs:comment> 
> >                 <ts:term_status>stable</ts:term_status> 
> >         </rdfs:Class> 
> > 
> > The 'term_status' property may take one of three values: 'unstable'
> > 'testing' or 'stable'. 
> > 
> > These values correspond to the 'alpha' 'beta' and 'stable' 
> values given to
> > software releases. However, it is not entirely clear what 
> these values
> > should imply for RDF schema terms. 
> 
> Yeah, I based it on the terminology from Debian Linux. 
> 
> > I suggest the following definitions, as a starting point 
> ... to be clarified
> > and refined: 
> > 
> > unstable ... this term has been newly added, and no testing 
> has been carried
> > out. Implementations using this term should realise that 
> its meaning may be
> > expected to change, or it may be removed at any time. 
> 
> I think the 2nd part is key. Something could be unstable for months
> ('newly' is vague; do we read it as days, months, years...?). 
> It is all
> about whether 3rd parties should build mission critical things that
> depend on its current form. The 'unstable' flag is a way of 
> saying 'this
> might change', 'might be poorly defined', 'feedback welcomed'.
> 
> > testing ... this term is currently undergoing testing and 
> evaluation. This
> > means that it will probably persist, although its exact 
> meaning may change. 
> 
> Yep, 'seems to be firming up.', 'gone beyond the raw proposal stage,
> might still change of course but that's life', 'we'll bear in mind the
> cost to early implementors when considering changes, but 
> won't be overly
> bound by such concerns if wider interop / long term stability is at
> stake', etc.
> 
> > stable ... this term is stable and has been subjected to testing and
> > evaluation. Implementers can expect this term to persist, 
> and for its
> > meaning to remain unchanged. 
> 
> stable means 'No substantive (meaning changing) alterations planned',
> 'time to get a tattoo!', ...
> 
> > All status changes within SKOS RDF schemas will be reported 
> on the SKOS
> > change log 
<http://esw.w3.org/mt/esw/archives/cat_skos_changelog.html>. 

A good plan!

> 3: Deprecation and Replacement of Terms
> 
> To manage the deprecation and replacement of terms within the schema, I
> propose the use of the owl:DeprecatedClass and owl:DeprecatedProperty
> classes. ... the owl:versionInfo property is then used to indicate what
> class or property should now be used instead. 

Neat
> 
> For example ... 
> 
>         <owl:DeprecatedClass rdf:ID="TopConcept"> 
>                 <rdfs:label>Top Concept</rdfs:label> 
>                 <rdfs:comment>A concept that sits at the top of the
concept
> hierarchy.</rdfs:comment> 
>                 <owl:versionInfo>This class is now deprecated.  To
indicate
> the top concepts for a particular scheme, use the new skos:hasTopConcept
> property instead.</owl:versionInfo> 
>         </owl:DeprecatedClass> 

Hmm, depends if Concepts are Classes, though?

Dan 
> 
> Yours,
> 
> Alistair.
> 
> ---
> Alistair Miles
> Research Associate
> CCLRC - Rutherford Appleton Laboratory
> Building R1 Room 1.60
> Fermi Avenue
> Chilton
> Didcot
> Oxfordshire OX11 0QX
> United Kingdom
> Email:        a.j.miles@rl.ac.uk
> Tel: +44 (0)1235 445440
> 
Received on Monday, 26 July 2004 12:16:03 GMT

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