Re: PROV-ISSUE-1 (define-resource): Definition for concept 'Resource' [Provenance Terminology]

Some comment interleaved, Jun

On 05/25/2011 11:56 AM, Jun Zhao wrote:
> Hi Luc,
> Some comments to your example inline ...
>> The challenge is to deal with dynamic contents.
> First of all, I think it might make sense to add some time information 
> in your examples, which is exactly what I did below.
>> Illustration inspired by the example.
>> - government (gov) converts data (d1) to RDF file (f1) at time (t1)
>> using xlst transform
>> - government (gov) uploads RDF data (f1) into a triple store, exposed
>> as  Web resource (r1)
>> - analyst (alice) downloads a turtle serialization (lcp1) of the
>> resource (r1) from government portal
>> Illustrations:
>> - r1: is a resource: it's the triple store, its a container, its content
>> can vary over time
> Is r1 a resource or a resource state? IMO, r1 accessed by gov at time 
> t1 should be a different resource state from that r1 accessed by alice 
> at time t2.

I think that, in the Web architecture, it is possible that multiple GET 
operations can retrieve representations of a same resource state (if the 
resource is not updated in between GET operations).

So r1 is the container, and remains a container all the time. It's a 
resource for me.

When government uploads the contents of f1 in the container, a new state 
is created.  If there is no more update to the container,
then the resource state representation retrieved by alice is the r-text 
of this state.
>> - lcp1: is a r-text (turtle serialization) of a given snapshot (created
>> by, or available at the time of, download)
> That even convinced me more that r1 is a resource snapshot.

No, I see r1 as the container.
>> - f1 is a local file: it can be seen as a stateless anonymous resource,
>> with a single r-text.
> If f1 is a file, then it is a representation of a resource, not a 
> resource any more, right?

I think the file has become is itself a new resource. If we don't update 
the file, it has a single state.
And also, it has a single representation.

>> If in addition:
>> - analyst (alice) downloads a rdf/xml serialization (lcp2) of the
>> resource (r1)
>> If the content of r1 has not changed, then lcp2 and lcp1 are both
>> r-texts of a same r-snapshot.
> Again, what is r-snapshot here now? And lcp2 and lcp1 shouldn't be 
> r-texts of the /*same*/ r-snapshot, because they were retrieved at 
> different time stamp, right?

Maybe time is confusing the issue here.  The time you seem to refer to 
is the "reading time". And indeed, we have two separate reading times
t1 and t2.

If the read operation is a pure read and does not update the container, 
than the state of the container has not changed (assuming no other 
updates). So, we would have the same state, i.e. same r-snapshot.


> cheers,
> Jun
>> Note that this is not limited to RDF (as Graham mentioned)
>> - newspaper (news), uses a CMS to publish the incidence map (map1),
>> chart (c1) and
>>     the image (img1) within a document (art1) written by (joe) using
>>     license (li2)
>> - newspaper (news), updates art1, adding a correction following a
>> complaint from a reader
>> Illustrations:
>> - art1 is a also resource, with two r-snapshots (before and after
>> correction)
>> - with language negotiation, an http client can download  html and xhtml
>> representations (i.e., r-texts) of the article
>> What do you think?
>> Cheers,
>> Luc
>> On 05/25/2011 06:49 AM, Paul Groth wrote:
>>> Hi,
>>> To throw out some, perhaps simpler, definitions into the mix that I
>>> think follow along the lines of what's being discussed.
>>> Resource - something that can be identified
>>> Snapshot - the state of a resource at particular point in time
>>> In the Data Journalism Scenario: a 'resource' would be the web page. a
>>> 'snapshot' would be the web page before publication.
>>> cheers,
>>> Paul
>>> Note: Similar concepts are found within many provenance models that I
>>> know of....if it's helpful I can list those out

Professor Luc Moreau
Electronics and Computer Science   tel:   +44 23 8059 4487
University of Southampton          fax:   +44 23 8059 2865
Southampton SO17 1BJ               email:
United Kingdom           

Received on Wednesday, 25 May 2011 11:21:44 UTC