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Re: PROV-ISSUE-186: Section 5.2.1 (PROV-DM as on Nov 28) [prov-dm]

From: Luc Moreau <L.Moreau@ecs.soton.ac.uk>
Date: Mon, 13 Feb 2012 07:49:07 +0000
Message-ID: <EMEW3|45aeeeb85b5d0c445321a3c12c46dee5o1C7nB08L.Moreau|ecs.soton.ac.uk|4F38C073.4070808@ecs.soton.ac.uk>
To: Satya Sahoo <satya.sahoo@case.edu>
CC: public-prov-wg@w3.org
Thanks Satya, it's now closed.
Luc

On 02/11/2012 12:59 AM, Satya Sahoo wrote:
> Hi Luc,
> As you mentioned, this issue has been superseded and I am fine with 
> closing this issue.
>
> Thanks.
>
> Best,
> Satya
>
> On Wed, Dec 7, 2011 at 6:08 AM, Luc Moreau <L.Moreau@ecs.soton.ac.uk 
> <mailto:L.Moreau@ecs.soton.ac.uk>> wrote:
>
>     Hi Satya,
>
>     This discussion about identifier is now the remit of
>     PROV-ISSUE-183.  Once PROV-ISSUE-183 is resolved,
>     I think this one is also resolved.
>
>     Further responses interleaved.
>
>     On 12/07/2011 01:50 AM, Provenance Working Group Issue Tracker wrote:
>
>         PROV-ISSUE-186: Section 5.2.1 (PROV-DM as on Nov 28) [prov-dm]
>
>         http://www.w3.org/2011/prov/track/issues/186
>
>         Raised by: Satya Sahoo
>         On product: prov-dm
>
>         Hi,
>         The following are my comments on Section 5.2.1 of the PROV-DM
>         as on Nov 28:
>
>         Section 5.2.1:
>         1. "entity record is a representation of an entity."
>
>         Comment: So, we make provenance assertions about the entity or
>         the entity record? How is a provenance assertion about the
>         entity differentiated from an entity record?
>
>
>     The entity is the thing and its situation in the world, the entity
>     record is what we hold in a provenance record.
>     We're making assertions about entities.
>
>         For example, is there is a difference between:
>         a) entity(e0, [ prov:type="File", ex:path="/shared/crime.txt",
>         ex:creator="Alice" ])
>         and
>         b) e0 has size 10KB on disk - this assertion clearly does not
>         mean that the entity record "entity(e0, [ prov:type="File",
>         ex:path="/shared/crime.txt", ex:creator="Alice" ])" has size
>         10KB! The entity record, with about 80 characters, may have
>         size 1KB on disk.
>         e0 is a representation of the entity (located at
>         /shared/crime.txt and created by Alice). In any knowledge
>         representation approach and in information systems, we always
>         work with representation of the real world thing and refer to
>         these representations by an identifier. Clearly entity and its
>         records are two distinct information resources. How is fusing
>         entity and its record into single identifier relevant for
>         modeling provenance of entities?
>
>         2. "id: an identifier id identifying an entity; the identifier
>         of the entity record is defined to be the same as the
>         identifier of the entity; "
>
>
>         Comment: If the id of entity and entity record are the same,
>         then how can two distinct set of assertions about the same
>         entity exist?
>         If we use wasComplementOf Approach: We will create a new
>         identifier everytime we want to make an assertion about the
>         same entity?
>         E.g. Harvard University was established in the 17th century.
>              Harvard University was established in the year 1636.
>         will require two distinct identifiers for Harvard University?
>         Using wasComplementOf does not solve the problem since if
>         there are 100,000 assertions about Harvard University we will
>         end creating 100,000 identifiers and will have to link them
>         together using 100,000 wasComplementOf properties. This is
>         clearly an overly complicated modeling approach. More
>         importantly, this goes against the Web architecture approach
>         of re-use identifiers instead of minting new ones (in this
>         case clearly avoidable):
>         > From the AWWW [1] :
>         a. Good practice: Avoiding URI aliases - "A URI owner SHOULD
>         NOT associate arbitrarily different URIs with the same resource."
>
>         [1] http://www.w3.org/TR/2004/REC-webarch-20041215/#uri-aliases
>
>
>     I don't think we do, do we?
>
>         3. "If an asserter wishes to characterize an entity with the
>         same attribute-value pairs over several intervals, then they
>         are required to assert multiple entity records, each with its
>         own identifier (so as to allow potential dependencies between
>         the various entity records to be expressed)."
>
>         Comment: If the entity has to be characterized with different
>         attribute-value pairs over same intervals, do they create
>         distinct identifiers?
>
>
>     An example illustrating this case is covered in section 8 of the
>     document.
>
>     Luc
>
>         Thanks.
>
>         Best,
>         Satya
>
>
>
>
>
>     -- 
>     Professor Luc Moreau
>     Electronics and Computer Science   tel: +44 23 8059 4487
>     <tel:%2B44%2023%208059%204487>
>     University of Southampton          fax: +44 23 8059 2865
>     <tel:%2B44%2023%208059%202865>
>     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
>     <http://www.ecs.soton.ac.uk/%7Elavm>
>
>
>

-- 
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
United Kingdom                     http://www.ecs.soton.ac.uk/~lavm
Received on Monday, 13 February 2012 07:49:39 GMT

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