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[VM] VM Task Force update

From: Thomas Baker <tbaker@tbaker.de>
Date: Tue, 25 Oct 2005 12:33:42 +0200
To: SW Best Practices <public-swbp-wg@w3.org>
Message-ID: <20051025103342.GA1356@baker>

SWBPD VM Task Force - update

The most recent telecon was on 27 September [1].

The problem: What is returned when the URI of a vocabulary term
is dereferenced?   SKOS, FOAF, and DC handle this differently,
and the existing solutions are not optimal, but we are close
to agreement on a common approach.

Where we stand:

-- We agree that the solution should lie with content
   negotiation [2].  (Other options considered were embedded
   RDF (XHMTL 2.0) and RDF/A syntax, which however does not
   address deployed tools.)

-- Alistair has described how SKOS currently handles
   dereferencing URIs and proposed some changes to the current
   policy [3, 4, and attached below].

-- Tom has described how DCMI currently handles dereferencing
   [5] and endorses the requirements articulated by Alistair (see

-- Dan is working on a description and position with regard
   to FOAF.

I propose that by the end of the year, we:

-- Agree on the requirements (see below).

-- Agree on a "recipe" for implementation in Apache (e.g., below).

-- Wrap that recipe in a simple note describing the
   philosophy of, and a context for, this approach.


[1] http://www.w3.org/2005/09/27-vmtf-minutes.html
[2] http://www.w3.org/TR/webarch/#def-coneg
[3] http://lists.w3.org/Archives/Public/public-swbp-wg/2005Sep/0116.html
[4] http://lists.w3.org/Archives/Public/public-swbp-wg/2005Oct/0024.html
[5] http://lists.w3.org/Archives/Public/public-swbp-wg/2005Jul/0002.html

Date: Mon, 3 Oct 2005 17:44:10 +0100
From: Alistair Miles <A.J.Miles@rl.ac.uk>

Requirements for URI dereferencing of RDF(S) classes and props:

(1) If a person tries to dereference the URI of a class or
    property (i.e. via a web browser), they end up at the relevant
    bit of human-readable documentation.

(2) If a machine tries to dereference the URI of a class
    or property, they end up with a serialisation of a set of
    RDF statements describing that class or property, with
    a provenance that allows differentiation of different
    'versions' of an RDF schema/ontology.

(3) The whole thing complies with TAG resolution on httpRange-14.

E.g. Implementation with Apache 1.3 (probably works for 2.0 too although 
I haven't checked)for 'hash' namespace 

In directory corresponding to URL /2004/02/skos/ there is a type-map 
file (e.g. 'core.var') containing the following...

URI: core

URI: core-latest-rdf
Content-type: application/rdf+xml

URI: core-latest-html
Content-type: text/html

URI: core-latest-html
Content-type: text/xml

URI: core-latest-html
Content-type: application/xml

URI: core-latest-html
Content-type: application/xhtml+xml

... and in directory corresponding to URL /2004/02/skos/ there is a 
.htaccess file containing the following...
Options -MultiViews
RewriteEngine On
RewriteRule ^core$ core.var
RewriteRule ^core-latest-rdf$ /2004/02/skos/core/history/2005-03-31 
RewriteRule ^core-latest-html$ /TR/2005/WD-swbp-skos-core-spec-20050510 

N.B. this is not actually implemented for 
http://www.w3.org/2004/02/skos/core although it is proposed to do so.  
It is implemented for the dummy resource 
http://www.w3.org/2004/02/skos/bar to test that it works.

Dr. Thomas Baker                      baker@sub.uni-goettingen.de
SUB - Goettingen State                            +49-551-39-3883
and University Library                           +49-30-8109-9027
Papendiek 14, 37073 Göttingen
Received on Tuesday, 25 October 2005 10:33:53 UTC

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