W3C home > Mailing lists > Public > public-lod@w3.org > March 2012

Re: What would break? Re: httpRange-14

From: Kingsley Idehen <kidehen@openlinksw.com>
Date: Tue, 27 Mar 2012 16:55:45 -0400
Message-ID: <4F722951.70309@openlinksw.com>
To: public-lod@w3.org
On 3/27/12 3:39 PM, David Wood wrote:
> Hi all,
>
> Maybe we've been going about this backward.
>
> Most Web pages aren't "about" anything other than their contents.

Correct!

They bear content that at best (in most cases) mention things in loose ways.

>   They are IRs, in the old terminology that we daren't use anymore :)  Some Web pages are representative of other things, like Danny's dog or a person or an organization.

Some may actually bear structured content that explicitly describes a 
subject. The subject may or may not be unambiguously named.

>    For those (and for those only) we want some way of identifying both the Web page (its URL) and the thing itself (a new URI).

You want to separate the document from the subject it describes, when 
said document is of kind: descriptor. Of course, there are times (as a 
consumer) where you seek to apply inference (not talking OWL here)  to 
the content and produce a more structured alternative. In addition, you 
may want embellish you actions with provenance oriented annotations.
>
> So, why not provide a standard way for those Web resources that are representative of real-world things (or concepts) to advertise the additional URI for the thing that they provide information about?

That happens implicitly with hash URIs. Alternatively, this occurs 
explicitly via the contentious 303 redirection heuristic, if the 
description subject is named / identified using a hashless URI. As 
you've already indicated, there are two *things* i.e, a descriptor 
document and its unambiguously named subject. Both need to be 
unambiguously named / identified when making an effective/useful 
description.

>
> For example, these two Web pages are both about me:
>    http://3roundstones.com/about-us/leadership-team/david-wood/
>    http://www.w3.org/2011/rdf-wg/wiki/User:Dwood4
> Wouldn't it be nice if the HTML representation that came back from both of them with a 200 also provided a header with the same unambiguous URI identifying me?  We could then safely use that new URI as the subject of RDF statements that are about me.

If you have an RDF profile document, why not simply expose it via 
<link/> relation in the <head/> section of: 
http://3roundstones.com/about-us/leadership-team/david-wood/, which you 
more than likely have CRUD privileges over?

As per my comment to Jeni, also ensure your RDF document includes a 
relation that connects it to what it describes. You will be set. No 
content negotiation required, no 303, your URI will be part of the Web 
for Linked Data.

Links:

1. http://goo.gl/DRvQM -- see the diagrams in this post, I have 
illustrations for hash and slash URIs for description document subjects.



Kingsley
>
>
> Regards,
> Dave
>
>
>
>
> On Mar 27, 2012, at 04:44, Jeni Tennison wrote:
>
>> On 27 Mar 2012, at 06:45, Pat Hayes wrote:
>>> On Mar 26, 2012, at 12:27 PM, Tim Berners-Lee wrote:
>>>> The SWAP project, CWM has that built in -- the URI of the document
>>>> something was read from is kept in the quad store as provenance
>>>> for every triple read in.
>>> OK, but that does not mean that this URI actually denotes that document in RDF. Maybe the semantics of the fourth field in a quad store is different from that of fields in an RDF triple. (In fact, I think we are goingto *have* to assume it is different in order to give any kind of coherent semantics for quad stores.)
>>>
>>> The acid test would be whether you use this URI *inside an RDF triple* with this 'document provenance' meaning.
>>
>> I was thinking something similar. Using the URI of the resource from which you gleaned some RDF as the identifier for a graph in a quad store is at best a convenient fiction. If you were to ever add statements about that graph to actually record things such as when you retrieved it, which user agent string you used, which Accept header you used, what processing you put it through which which version of your software and so on -- vital statements about the provenance of the RDF that you've gleaned, I would have thought -- then really you would have to use a separate identifier for the graph than for the resource on the web.
>>
>> But, just like using a URI to refer to a Person or Organisation, reusing the URI of a resource for a graph is a convenient thing to do. In my opinion, we need to recognise that people will do the convenient thing and (a) have a protocol that is flexible enough to cope when they do so (call this error recovery if you like) and (b) provide understandable routes from the convenient path to a more rigorous one.
>>
>> Cheers,
>>
>> Jeni
>> -- 
>> Jeni Tennison
>> http://www.jenitennison.com
>>
>>
>
>


-- 

Regards,

Kingsley Idehen	
Founder&  CEO
OpenLink Software
Company Web: http://www.openlinksw.com
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Received on Tuesday, 27 March 2012 20:56:05 UTC

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