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Re: A proposed provenance wg draft charter

From: Simon Miles <drsimonmiles@gmail.com>
Date: Mon, 25 Oct 2010 20:36:47 +0100
Message-ID: <AANLkTi=qJ1L9LX77QUz3dZsvSNSf7bVqJGTe+5+CXU_-@mail.gmail.com>
To: Daniel Garijo <dgarijo@delicias.dia.fi.upm.es>
Cc: public-xg-prov@w3.org
Hi Daniel, (all)

Agreed with your point below.  I would just like to (shamelessly :-))
say that this issue was one which I needed to address as part of
mapping OPM to Dublin Core in the accepted journal article whose
pre-print is linked below.  In summary, one can describe mutable
resource changes in OPM given some common vocabulary for annotations
(whether part of OPM or a profile on top of it) allowing us to state
all of: "artifact X is an instance of resource R", "artifact Y is an
instance of resource R", and "artifact X derives from artifact Y in
being a later instance of the same resource".  There will, of course,
be other ways to address the gap.  It seems an important issue but
maybe not a substantial problem given the way OPM already allows



On 25 October 2010 20:06, Daniel Garijo <dgarijo@delicias.dia.fi.upm.es> wrote:
> Hi Paolo, all.
> In the OPM, artifacts are defined as "inmutable pieces of state", so if a
> resource changes in any way(it changes its state),  wouldn't that led to a
> new artifact derived from the original one? I think that that's what Olaf
> means when he says that we can not track the provenance of a resource, only
> the provenance of the "snapshots" or "representations" from that resource
> (please correct me if I'm wrong).
> Versioning is one of the aspects that is not well captured by OPM according
> to the conclusions of the Provenance Vocabulary Mappings, so it should be
> one of the "refinements" to be done to the model in order to build a
> standard.
> Best,
> Daniel
> 2010/10/25 Paolo Missier <pmissier@acm.org>
>> Olaf,
>>>> why wouldn't resources have provenance?
>>> The problem is that a Web resource may change; it may have a different
>>> state at
>>> a different point in time. What would the provenance of such a changing
>>> thing
>>> be?
>> well, if a resource changes its state, I would assume that its provenance
>> will actually account for those state changes? isn't that within the scope
>> of its model?
>>> A specific representation of a Web resource cannot change. That's why I
>>> find it
>>> much easier to talk about the provenance of such representations rather
>>> than
>>> the Web resource itself.
>>> That's probably also why artifacts in OPM are immutable pieces of state.
>> ok, but in my mind artifacts (in the OPM sense, for example) stand for
>> resources, rather than their representations.
>> maybe I don't quite understand what you mean by a representation of a
>> resource, here. If a resource changes its state, wouldn't its representation
>> (whatever it is) change as well?
>> I would find it natural to talk about data versioning (accounting for
>> state changes) along with data dependencies (amongst specific versions of a
>> set of resources), within the same provenance framework.
>>>> just like a piece of data in a database.
>>> In the case of a database I would also prefer to associate provenance
>>> with
>>> manifestations of the data. For instance, given a table, I would not
>>> associate
>>> provenance with the table per se but with a specific version / state of
>>> the
>>> table. Same with a cell in such a table: I would associate provenance
>>> with a
>>> specific attribute value thats in the cell rather than with the cell
>>> itself.
>> sure, although these two are not the same example: the former is
>> associating provenance to a version, which is pretty much what I was
>> implying above, while the latter is a matter of granularity within the same
>> state -- but I agree that both should be there
>>>> I see it the opposite way: isn't the provenance of a
>>>> manifestation of a resource is just (some view of) the provenance of the
>>>> resource itself?
>>> I wouldn't say so. What you say would mean that multiple different
>>> manifestations of the same (state of the same) Web resource have the same
>>> provenance (even if different views on it). Shouldn't they have different
>>> provenance (even if several pieces of their provenance are overlapping)?
>>> Let's say, both of us retrieve a representation of a Web resource; we do
>>> it at
>>> the same point in time; so, if we are lucky, we have two representations
>>> that
>>> represent the Web resource in the same state. Nonetheless, I think these
>>> two
>>> representations have different provenance.
>> ok, but isn't their difference "only" in the last, retrieval step? they
>> effectively represent the same resource, under the retrieval conditions you
>> describe, only the last access step changes, and it's not clear to me that
>> that is part of the resource's provenance
>> interesting thread, anyway -- not sure it will have an impact on the
>> proposed charter though :-)
>> -Paolo
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Dr Simon Miles
Lecturer, Department of Computer Science
Kings College London, WC2R 2LS, UK
+44 (0)20 7848 1166
Received on Monday, 25 October 2010 19:37:21 UTC

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