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RE: proposed response to public comment (deadline Tuesday noon GMT)

From: Miles, Simon <simon.miles@kcl.ac.uk>
Date: Fri, 2 Nov 2012 14:59:46 +0000
To: "public-prov-wg@w3.org" <public-prov-wg@w3.org>
Message-ID: <830EEE5C741ED54EAB28EBACFFC77984EEBA804508@KCL-MAIL04.kclad.ds.kcl.ac.uk>
Hi Luc,

+1

I find mentionOf unintuitive and am not convinced it will be useful (for reasons that the group as gone over plenty in previous discussions), but I've no problem with the response and am in favour of the strategy of testing the concept's usefulness through implementation at CR stage.

thanks,
Simon

Dr Simon Miles
Senior Lecturer, Department of Informatics
Kings College London, WC2R 2LS, UK
+44 (0)20 7848 1166

Efficient Multi-Granularity Service Composition:
http://eprints.dcs.kcl.ac.uk/1396/

________________________________
From: Luc Moreau [l.moreau@ecs.soton.ac.uk]
Sent: 01 November 2012 16:33
To: public-prov-wg@w3.org
Subject: proposed response to public comment (deadline Tuesday noon GMT)


Dear all,

At http://www.w3.org/2011/prov/wiki/ResponsesToPublicComments#PROV-DM_.28Under_Review.29
you will find proposed answers to the ISSUE-475. It is copied below for your convenience.

It will become the group response unless we hear objections by Tuesday November 6th, noon GMT.

Best regards,
Luc

ISSUE-475 (Mention)

 *   Original email: http://lists.w3.org/Archives/Public/public-prov-comments/2012Aug/0001.html
 *   Tracker: http://www.w3.org/2011/prov/track/issues/475
 *   Group Response:
    *   The reviewer suggests that the work to describe contextualized provenance should be deferred so that it can be aligned with ongoing W3C work on RDF datasets and their semantics. Since ISSUE-475 was submitted, the RDF working group has decided that it will not provide a formal semantics for RDF Datasets. This RDF resolution ensures that any semantics for bundle and/or mention is guaranteed not to be in conflict with the RDF semantics.
    *   As PROV-Constraints section 6.2 clearly indicates, PROV-bundles validity is determined by examining bundles in isolation of each other. Our response to issue-482 also indicates that PROV itself does not set any constraints on how a given ID is being used across multiple bundles. Given this, mentionOf is a general relation which allows an entity to be linked to another entity described in another bundle.
    *   The reviewer suggests that

   mentionOf(infra, supra, b)


could simply be expressed as

  specializationOf(infra, supra)
  entity(infra, [mentionedIn=b])


 *
    *   This design was considered and rejected by the Working Group:
       *   By design, relations between PROV objects are expressed by PROV relations (usage, generation, etc, mention), and are not expressed as PROV attributes. The suggested additional attribute mentionedIn would relate the entity infra with bundle b, and would go against this prov-dm design.
       *   The interpretation of the attribute-value pair mentionedIn=b is somewhat difficult, because infra is not itself described in bundle b: supra is the entity described in bundle b. So, syntactically, mentionedIn=b may look like an attribute-value pair, but in reality, it can only be understood in the presence of specializationOf(infra, supra). Hence, the reason for introducing the ternary relation mentionOf.
    *   The Working Group left it unspecified which new attributes could be inferred for infra, and in general what constraints apply to mentionOf. The reviewer is critical of this decision, arguing that nothing new can be inferred from mentionOf, and therefore mentionOf can be replaced by specializationOf. 'Under-specification' is a feature of PROV: what can be inferred from relations such as usage, derivation, alternate? The group recently acknowledged this for alternateOf and added a clarifiying note in the text. This observation is applicable to further PROV concepts, such as Quotation, PrimarySource, SoftwareAgent, etc. which do not allow us to infer more than their parent concept would (Derivation, Agent). We are in a same situation with mentionOf. Further inferences are left to be specified by applications.
    *   The reviewer's suggestion to address the use of Example 45 is to copy part of the referred bundle. By copying statements from the original context to the new context, we have lost the original context in which they occur (... their provenance!), and we have no way of expressing that wasAssociatedWith(ex:a1, ...) in the new context is a "kind of specialization" of wasAssociatedWith(ex:a1,...) in the original context, ... which is why mentionOf was introduced in the first place.
    *   The reviewer also comments on the lack of information about 'Fixed aspects'. We refer to our response to ISSUE-462, and recent associated changes to the document.
    *   The Working Group identified 'mention' as a feature at risk, because it was seeking experience from implementers. The Working Group will keep this feature marked at risk as it enters the CR phase, and will reassess its suitability based on implementers feedback.
 *   References:
    *   RDF resolution: http://www.w3.org/2011/rdf-wg/meeting/2012-10-03#resolution_1
    *   Email discussion on mention: http://lists.w3.org/Archives/Public/public-prov-wg/2012Jun/0400.html
    *   alternateOf: http://dvcs.w3.org/hg/prov/diff/60b6ee097555/model/prov-dm.html#l1.8
    *   Response to ISSUE-482: http://www.w3.org/2011/prov/wiki/ResponsesToPublicComments#ISSUE-482_.28Bundles_and_IDs.29
    *   Prov constraints section 6.2: http://www.w3.org/TR/prov-constraints/#bundle-constraints
    *   Response to ISSUE-462: http://www.w3.org/2011/prov/wiki/ResponsesToPublicComments#ISSUE-462_.28Definition_of_Entity.29
 *   Changes to the document:
 *   Original author's acknowledgement:

[edit<http://www.w3.org/2011/prov/wiki/index.php?title=ResponsesToPublicComments&action=edit&section=46>]



--
Professor Luc Moreau
Electronics and Computer Science   tel:   +44 23 8059 4487
University of Southampton          fax:   +44 23 8059 2865
Southampton SO17 1BJ               email: l.moreau@ecs.soton.ac.uk<mailto:l.moreau@ecs.soton.ac.uk>
United Kingdom                     http://www.ecs.soton.ac.uk/~lavm
Received on Friday, 2 November 2012 15:00:43 GMT

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