RE: ODRL RDF expression

Hi Stuart and Mo,

The code at
http://lodscope.parthenon.org.uk/index.xmp?uri=http%3A%2F%2Fptah.bencrannich
.net%2F2013%2FUNSTABLE%2Fvocab isn't really XMP - it has the XMP wrapper,
but everything inside <rdf:RDF> does not comply with the XMP specs.
The biggest drawback of XMP is that it is very weak in using a Subject (of
an RDF triple) which is not "this asset" (the image, the PDF document, the
...), therefore it is actually impossible to define an ODRL policy in an XMP
packet and to make assertions about this policy. My conclusion: it is
impossible to express ODRL in native XMP.

Therefore we discussed IPTC-internally the linking to an ODRL policy
document which is e.g. on a central "policy server" = what you, Mo,
proposed.
But not everybody is happy with this approach, the main contra is: a user
cannot read the policy without internet access and a working policy server.
And some are still behind the approach: embedded metadata define "this
metadata belong to this content" in the most obvious and reliable way.
For that approach we were discussing to embed ODRL serialized as XML or JSON
into a XMP field of data type Text.

That's a summary of our discussion inside IPTC. 

Best,
Michael

Michael Steidl
Managing Director of the IPTC [mdirector@iptc.org]
International Press Telecommunications Council 
Web: www.iptc.org - on Twitter @IPTC
Business office address: 
25 Southampton Buildings, London WC2A 1AL, United Kingdom
Registered in England, company no 101096

> -----Original Message-----
> From: Mo McRoberts [mailto:Mo.McRoberts@bbc.co.uk]
> Sent: Thursday, April 04, 2013 10:57 AM
> To: Myles, Stuart
> Cc: public-odrl@w3.org
> Subject: Re: ODRL RDF expression
> 
> Hi Stuart,
> 
> On Wed 2013-Apr-03, at 21:50, "Myles, Stuart" <SMyles@ap.org> wrote:
> 
> > Thanks for sending this, Mo.
> >
> > If wonder if it might be a good idea to host this kind of discussion
> somewhere on the ODRL website? http://www.w3.org/community/odrl/
> You might get a bit more engagement that way? (Lots of people on this
email
> list will be experts in ODRL, but may not be experts in RDF...).
> 
> Renato beat me to it, but yes -- more than happy for it to be spread
further
> and wider. I'll run it past some folks on #swig IRC too.
> 
> > One of the reasons that I was interested in ODRL in RDF is because I
want
> to be able to embed rights expressions for news content within binaries
> (such as photos). So, I had hoped that I could use an ODRL-in-RDF
> representation to embed within XMP
> http://en.wikipedia.org/wiki/Extensible_Metadata_Platform which is a
> subset of the RDF/XML syntax. As part of the IPTC's RightsML work
> http://dev.iptc.org/RightsML (to express permissions and restrictions for
the
> news industry using ODRL) we experimented with embedding RDF within
> XMP. We concluded that it wasn't possible to embed arbitrary RDF within
> XMP. So, it caught my eye that the lodscope link that you sent offers to
> represent your Turtle as XMP:
> >
> >
> http://lodscope.parthenon.org.uk/index.xmp?uri=http%3A%2F%2Fptah.ben
> crannich.net%2F2013%2FUNSTABLE%2Fvocab
> >
> > So, maybe that ODRL in XMP isn't a dead end after all? Do you know how
> the lodscope is creating the XMP (or how I could find out more)?
> 
> So XMP is extensible insofar as new vocabulary terms can be introduced
> without incident, but expressing ODRL meaningfully in XMP is difficult
> because its grammar is quite limited.
> 
> While it might be possible to define processing rules for ODRL-in-XMP, it
> might be a lot easier to either:
> 
> 1) embed a de-referencable identifier within the image, which when
> resolved returns data which includes ODRL
> 
> 2) define/adopt an XMP vocab term (maybe dc:license) which links directly
to
> an ODRL Policy document
> 
> I've implemented a variant of (1) using CC terms...
> 
> - The sample asset can be obtained here: http://sample2.acropolis.org.uk/
> 
> - A look-up tool which operates on it is here:
> http://rightstool.parthenon.org.uk/
> 
> At the moment it uses the 'dc:source' property within the XMP to express
> the de-referenceable identifier for the asset, but that's not intended to
be
> permanent.
> 
> (Once we're all happy with the RDF expression of ODRL, I intend to update
> both the sample and the tool to use it).
> 
> > Meanwhile, we've started to think that maybe ODRL in JSON might be a
> good way forward. Although JSON and RDF are not particularly similar
> syntaxes, it would be good to see if we can keep the two ODRL
> representation efforts loosely
> > aligned.
> 
> I'd suggest looking at JSON-LD: http://json-ld.org/ -- this lets you
express
> "full-fat" RDF in a form of JSON which doesn't scare away people who
aren't
> or don't want to be RDF-savvy (with the aid of a couple of pre-defined
> attributes with special meaning).
> 
> All the best,
> 
> M.
> 
> --
> Mo McRoberts - Analyst - BBC Archive Development,
> Zone 1.08, BBC Scotland, 40 Pacific Quay, Glasgow G51 1DA,
> MC3 D4, Media Centre, 201 Wood Lane, London W12 7TQ,
> 0141 422 6036 (Internal: 01-26036) - PGP key CEBCF03E
> 
> 
> 
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Received on Friday, 5 April 2013 14:48:35 UTC