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Re: AW: [Dbpedia-discussion] Fwd: Your message to Dbpedia-discussion awaits moderator approval

From: Hugh Glaser <hg@ecs.soton.ac.uk>
Date: Wed, 12 Aug 2009 01:56:15 +0100
To: Peter Ansell <ansell.peter@gmail.com>
CC: "public-lod@w3.org" <public-lod@w3.org>, "dbpedia-discussion@lists.sourceforge.net" <dbpedia-discussion@lists.sourceforge.net>
Message-ID: <EMEW3|87b601b5d7a95f19ae339e64099c7a20l7B1uQ02hg|ecs.soton.ac.uk|CC86%hg@ecs.soton.ac.uk>
Dear Peter,
Thank you for your comments, which I think raise the main issues.

On 12/08/2009 01:11, "Peter Ansell" <ansell.peter@gmail.com> wrote:

> 2009/8/12 Hugh Glaser <hg@ecs.soton.ac.uk>:
>> Are you saying that the only way to access Linked Data is via SPARQL?
> 
> That is going a bit far, but in the end if you want to allow people to
> extend the model it has to be done using SPARQL. If the extension is
> taken well by users then it could be included in what is resolved for
> the URI but that doesn't mean it is not Linked Data up until the point
> it is included.
My view is that if you need to extend (I would say "step outside") the
model, then something is broken. Or at least it is broken until the model
includes the extension, as you suggest. So we need to work out how to
include such extensions in the model, if such a thing is desirable.

Did I go too far?
I'm not sure. I have a sense that the suggested solution to any problem I
raise is "Oh don't worry, just use a Named Graph".
But "How to Publish Linked Data on the Web"
(http://www4.wiwiss.fu-berlin.de/bizer/pub/LinkedDataTutorial/),
which really is an excellent description of what I think should be
happening, makes no real mention of the idea that a SPARQL endpoint might be
associated with Linked Data.
In fact, it says that if you have a SPARQL endpoint (for example using D2R),
you might use Pubby "as a Linked Data interface in front of your SPARQL
endpoint."
And pubby says:
"Pubby makes it easy to turn a SPARQL endpoint into a Linked Data server."
I infer from this that SPARQL endpoints are optional extras when publishing
Linked Data. So any solutions to problems must work simply by resolving
URIs.
> 
> I for one loved the recent addition of the Page Links set in a
> separate Named Graph, and I don't see how this is different.
That's great.
I'd be interested to know how you make use of them?
We find it very hard to make use of Named Graph data.
All we start with is a URI for a NIR; so all we can do is resolve it.
We cache the resulting RDF and then use it for analysis and fresnel
rendering.
It is pretty hard to build in anything that takes any notice of Named Graphs
at arbitrary Linked Data sites. We would need to be able to find the SPARQL
endpoint from a URI so that we can do the DESCRIBE, and then also be able to
specify a Named Graph to go with it. In fact, how would I do that from
http://dbpedia.org/resource/London ?

I'm afraid I find Linked Data (by resolving URIs) really beautiful, and
think I can understand how I and others might use it. So when it is
suggested that the way to solve an issue with how it works is to step
outside the RDFramework, I think it needs to be challenged or brought into
the Framework.
> 
> Cheers,
> 
> Peter
> 
Cheers Peter.
Hope that helps to show where I come from.
Best
Hugh
Received on Wednesday, 12 August 2009 00:58:52 UTC

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