W3C home > Mailing lists > Public > public-prov-wg@w3.org > April 2012

Re: actions related to collections

From: Paolo Missier <Paolo.Missier@ncl.ac.uk>
Date: Fri, 20 Apr 2012 13:49:47 +0100
Message-ID: <4F915B6B.6070105@ncl.ac.uk>
To: Provenance Working Group <public-prov-wg@w3.org>

on the question of whether or not part-of relations (in general) belong in the DM:

To be honest, I don't mind either way. I know I need to extend Derivation with the specific relations for expressing state change in 
part-of relations, because they have a more specific meaning, so I would just use these. If they are not part of a recommendation, 
then another set may emerge to achieve a similar effect. That's fine, as long as we can still interoperate. Perhaps this is a part 
of the W3C process I don't understand: to what extent can you still pursue interop with some chance of success, in areas that are 
not covered by a recommendation. Is a Note the right way? If so, why not.

And another (genuine!) question: what's the rationale for having Collections in RDFs, in fact there's rdf:Bag, rdf:Set, rdf:Seq, and 
rdf:List.  I imagine, because those are data structures that one naturally wants to map to RDF graphs. So the question is, is it 
legitimate to transpose this argument to the provenance space?


On 4/19/12 9:45 PM, Timothy Lebo wrote:
> On Apr 19, 2012, at 10:56 AM, Miles, Simon wrote:
>> Hello Curt,
>> I don't have a particular problem with collections being described in a separate document from the DM.
>> However, I would still argue that they are special for provenance and it is not merely about the prevalance or importance of collections across domains where provenance is used.
> +1. Dictionaries provide a much richer notion of provenance that is not immediately available in the "fundamental" constructs.
> It should be in the Recommendation to establish this important second layer. The fact that it also uses the "fundamental" constructs is an eloquent side benefit, not a case to argue that it is superfluous.
> -Tim
>> In particular:
>> 1. Almost everything has parts, and the provenance of something is partly the provenance of its parts. If I ask for the provenance of a webpage, I don't just want to know who designed the page as a whole, but also where the images came from, what license they were published under etc. The latter provenance descriptions concern the images, but the question is about the page, so the relation between them is directly relevant to provenance.
>> 2. Because of the first point above, knowing when parts are inserted or removed is also important to understanding something's provenance. What happened to an image after it was removed is not relevant to the provenance of the page that contained the image. What happened to the image before it was inserted did not affect the page until it was inserted, while every change to the image after insertion affects the page at the same time.
>> I'd therefore argue that collections, including membership, insertion and deletion, are vital to understanding provenance, not just coincidentally prevalent.
>> thanks,
>> Simon
>> Dr Simon Miles
>> Senior Lecturer, Department of Informatics
>> Kings College London, WC2R 2LS, UK
>> +44 (0)20 7848 1166
>> Automatically Adapting Source Code to Document Provenance:
>> http://eprints.dcs.kcl.ac.uk/1397/
>> ________________________________________
>> From: Curt Tilmes [Curt.Tilmes@nasa.gov]
>> Sent: 19 April 2012 15:35
>> To: public-prov-wg@w3.org
>> Subject: Re: actions related to collections
>> On 04/12/2012 05:06 PM, Luc Moreau wrote:
>>> Hi Jun and Satya,
>>> Following today's call, ACTION-76 [1] and ACTION-77 [2] were raised
>>> against you, as we agreed.
>>> [1] https://www.w3.org/2011/prov/track/actions/76
>>> [2] https://www.w3.org/2011/prov/track/actions/77
>> I've been going over the "collections" traffic.
>> I mentioned this briefly on the call last week, but I'll state it
>> once more for the record, then keep my peace.
>> The bulk of PROV-DM is describing what I'll call core or fundamental
>> concepts for describing provenance.
>> You have a general 'entity', it gets 'used' by an 'activity' and
>> 'generates' a new 'entity'.  Those concepts are all necessary to the
>> data model, and it doesn't hold together without them.
>> Collections, IMHO, don't fall into that category.
>> They should be a layer on top of the DM, not a set of fundamental
>> concepts beside the others or integrated with them.
>> A collection is simply another type of entity, it changes in several
>> ways, the previous instance of it getting used by various activities,
>> resulting in the generation of a new entity.
>> We should model that just like any other entity that gets changed in
>> any number of ways.  Insertion/Removal are just like any other
>> activities.  They use one entity (the previous collection), make some
>> changes, and generate a new entity (the next version of the
>> collection).  They aren't 'special' enough to include in PROV-DM.
>> One could argue (several of you have) that collections are very
>> important, since they cross so many domains. I could buy that, but
>> there are also many different types of collections (touched on by the
>> discussion) and the types of representations and changes that happen
>> to the collections, and importance of various aspects of provenance of
>> those changes are different for each of them.
>> Take what we have here, make it a Collection Provenance Model or
>> something like that, and propose it separately as a middle layer on
>> top of PROV, below all the "Provenance of XXX"s that will be needed
>> for various domains, but leave it out of PROV-DM.
>> My 2 cents,
>> Curt

-----------  ~oo~  --------------
Paolo Missier - Paolo.Missier@newcastle.ac.uk, pmissier@acm.org
School of Computing Science, Newcastle University,  UK
Received on Friday, 20 April 2012 12:50:20 UTC

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