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Re: ISSUE-385: hasProvenanceIn: finding a solution

From: Jun Zhao <jun.zhao@zoo.ox.ac.uk>
Date: Sat, 2 Jun 2012 22:36:39 +0100
To: Paul Groth <p.t.groth@vu.nl>
Message-Id: <2695B88A-131B-4E10-A395-5E9E076A0174@zoo.ox.ac.uk>
Cc: Luc Moreau <L.Moreau@ecs.soton.ac.uk>, "public-prov-wg@w3.org" <public-prov-wg@w3.org>
Paul,

At first sight, I loved your proposal. But after reading into it, I got less sure.

This property is to allow locating the bundle in which the provenance of an entity is described. To qualify this, would it mean that, e.g, there is a time period during which you can find provenance of that entity in the bundle and after that you can't? 

Although the pattern you propose makes sense, I can't see when people need to qualify this relation. If you have a more concrete example in mind, I am ready to be convinced!

Cheers,

Jun

Sent from my iPad (sorry for the brevity)

On 1 Jun 2012, at 17:03, Paul Groth <p.t.groth@vu.nl> wrote:

> Hi All,
> 
> It seems that a one approach would be to define an extensible version
> of hasProvenanceIn and leave it at that.
> 
> hasProvenanceIn(id, entity, bundle, attrs).
> 
> Like all our extensible relations, we would also have the straight
> binary version
> 
> hasProvenanceIn(entity,bundle)
> 
> This would allow for the extensibility to cater for Luc's use case but
> also for other use cases where extension is nice. For example, I can
> imagine a system wanting to put a time constraint on the applicability
> of provenance in a bundle to an entity.
> 
> This would leave it up to people to define specialization, alternate
> and derivation relations between entities as they want.
> 
> Would this be acceptable to the group?
> 
> Thanks
> Paul
> 
> 
> 
> On Fri, Jun 1, 2012 at 5:33 PM, Luc Moreau <L.Moreau@ecs.soton.ac.uk> wrote:
>> Hi Simon,
>> 
>> Thanks for your message. I feel you don't directly respond to the points
>> that I raised,
>> and therefore all my comments stand.
>> 
>> I respond to your points below.
>> 
>> On 06/01/2012 03:39 PM, Miles, Simon wrote:
>>> Hi Luc,
>>> 
>>> I will try to articulate the points which I think back up the binary relations proposal.
>>> 
>>> 1. As I understood, there is currently no semantics to a bundle. A querier can choose to consider the descriptions in the bundle or not (based on the bundle's provenance), but whether there are one or many bundles, the querier just has a set of PROV descriptions. The bundles need to be found and known to be relevant, which is why hasProvenanceIn (or isTopicOf) is needed. After that, which bundle a description is in is irrelevant and the bundling can be ignored. A specific extension of PROV may change this by adding semantics to bundles, but this is not in the current specification.
>>> 
>>> 
>> 
>> A close notion to bundle in prior provenance art is opm:Account, and
>> there is plenty of evidence
>> that merging accounts may lead to contradictions.  PROV, rightly so,
>> does not define a union operator
>> over bundles, and is silent about merging or not bundles.
>> 
>> Therefore,  there is nothing in PROV that backs this statement "which
>> bundle a description is in is
>> irrelevant and the bundling can be ignored".
>> 
>> You are suggesting that an extension of PROV may add semantics to
>> bundles: that's exactly what you
>> have done, by implying they are mergeable.
>> 
>>> Taking the statements from the three bundles below, a querier would end up with:
>>> 
>>>  activity(ex:a1, 2011-11-16T16:00:00,2011-11-16T17:0:00)
>>>  wasAssociatedWith(ex:a1,ex:Bob,[prov:role="controller"])
>>>  activity(ex:a2, 2011-11-17T10:00:00,2011-11-17T17:0:00)
>>>  wasAssociatedWith(ex:a2,ex:Bob,[prov:role="controller"])
>>>  agent(tool:Bob1, [perf:rating="good"])
>>>  agent(tool:Bob2, [perf:rating="bad"])
>>> 
>>> I can see nothing in the current specification to suggest this means anything different to when these descriptions are separated into multiple bundles. Do you agree?
>>> 
>>> 
>> 
>> PROV does not specify whether they mean something different or not.
>> 
>>> 2. If there are two entity identifiers relating to the same thing/entity, we need to say how they are connected: either alternateOf, specializationOf, or possibly some external relation such as owl:sameAs. While the example below happens to imply a specialisation relation between tool:Bob1 and ex:Bob, there is no reason to believe this is true in all cases: alternateOf is just as possible. So, hasProvenanceIn cannot imply or be a sub-type of either specializationOf or alternateOf, the appropriate one must be asserted separately.
>>> 
>> 
>> I agree that being able to assert subtypes for hasProvenanceIn is
>> important: that why I am
>> in favour of having hasProvenanceIn a n-ary relation that includes
>> attributes so that prov:type can be
>> used for what you suggest.
>>> 3. The same thing described from different perspectives has multiple identifiers regardless of bundles, i.e. at least one for each entity. When a bundle is newly read by a querier interested in the provenance of entity E, they should consider every entity E is a specialisation of, and look for those identifiers as well. If they don't, they will miss information about the provenance of E described at a coarser granularity.
>>> 
>>> For example, ex:Bob may be a specialisation of ex:GeneralBob, and bundle ex:run1 might describe something about ex:GeneralBob's provenance. This makes "hasProvenanceIn(tool:Bob1, ex:run1, ex:Bob)" strange, because it is not only ex:Bob that is relevant to look for in ex:run1.
>>> 
>>> Separating concerns, I'd argue it is preferable to say:
>>>  hasProvenanceIn(tool:Bob1, ex:run1)
>>>  specializationOf(tool:Bob1, ex:Bob)
>>>  specializationOf(tool:Bob, ex:GeneralBob)
>>> 
>> But this latter statement would belong to the ex:run1 bundle I assume.
>> It is not going to be known to be relevant to me until I have correctly
>> been able to link tool:Bob1 to ex:Bob in run1.
>> 
>> 
>>> and let the que
Received on Saturday, 2 June 2012 21:37:13 UTC

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