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Re: PROV-ISSUE-200: Section 6.3 (PROV-DM as on Dec 5) [prov-dm]

From: Satya Sahoo <satya.sahoo@case.edu>
Date: Tue, 14 Feb 2012 17:54:53 -0500
Message-ID: <CAOMwk6xpN01kgupSL-Z=ayAngGKe97aw=SAszOptyCppqvoWYw@mail.gmail.com>
To: Luc Moreau <L.Moreau@ecs.soton.ac.uk>
Cc: public-prov-wg@w3.org
Hi Luc,
I am fine with closing this particular issue (I will be raising issues
against the TPWD separately).

Thanks.

Best,
Satya

On Thu, Dec 8, 2011 at 6:04 AM, Luc Moreau <L.Moreau@ecs.soton.ac.uk> wrote:

> Hi Satya,
>
> This is again *very frustrating*. This PROV-ISSUE-50, and your last
> communication on this dates back from October 2nd!!!!
>
> http://lists.w3.org/Archives/**Public/public-prov-wg/2011Oct/**0007.html<http://lists.w3.org/Archives/Public/public-prov-wg/2011Oct/0007.html>
>
> You have not responded to my message on Oct 3rd
> http://lists.w3.org/Archives/**Public/public-prov-wg/2011Oct/**0009.html<http://lists.w3.org/Archives/Public/public-prov-wg/2011Oct/0009.html>
> and November 30th
> http://lists.w3.org/Archives/**Public/public-prov-wg/2011Nov/**0419.html<http://lists.w3.org/Archives/Public/public-prov-wg/2011Nov/0419.html>
>
> Further comments below.
>
> On 12/07/2011 02:22 AM, Provenance Working Group Issue Tracker wrote:
>
>> PROV-ISSUE-200: Section 6.3 (PROV-DM as on Dec 5) [prov-dm]
>>
>> http://www.w3.org/2011/prov/**track/issues/200<http://www.w3.org/2011/prov/track/issues/200>
>>
>> Raised by: Satya Sahoo
>> On product: prov-dm
>>
>> Hi,
>> The following are my comments for Section 6.3 of the PROV-DM (as on Dec
>> 5):
>>
>> Section 6.3
>> 1. Given:
>>
>> "An information flow ordering record is a representation that an entity
>> was generated by an activity, before it was used by another activity."
>>
>> How does the constraint:
>>
>> "Given two activity records denoted by a1 and a2, if the record
>> wasInformedBy(a2,a1) holds, then the following temporal constraint holds:
>> the start event of the activity record denoted by a1 precedes the end event
>> of the activity record denoted by a2."
>>
>> make sense?
>>
>> Detailed comment: Let us consider the scenario: "a chemical reagent r1
>> was generated by activity a1 in September 2011" and "r1 was used by
>> researcher in experiment activity a2 in December 2011". From a provenance
>> perspective, we simply state r1 was generated before it was used - where is
>> the relevance of activity ordering in above scenario (entity was generated
>> before it was used)?
>>
>>
> you will note that the above constraint is a necessary condition and not a
> sufficient condition!
>
> The point about information flow ordering is that the entity does not have
> to be explicitly mentioned.  It's an existential quantifier over an entity.
>
> If you activity a1 had started after the end of a2, it would have been
> impossible to have this entity r1 generated by a1 and used by a2.
>
>  Further, activity ordering is important in provenance from a very
>> different perspective - "analyzing provenance of bank transactions to
>> justify penalty fee for customer c1 - the $100.00 deposit activity da1 took
>> place before or after $80.00 withdrawal activity wa1 happened in account
>> with starting balance of $5.00". So, if da1 happened before wa1 there
>> should not be any penalty fee, otherwise customer has to pay fee for
>> withdrawing more money than was available in the account.
>>
>>
>
> This example is handled by having various account entities for the various
> balances.
> I don't think we need an explicit activity ordering here.
>
>  Clearly, the informedBy property does not address the requirement of
>> activity ordering for provenance. In addition, the current definition of
>> informedBy for representing whether entity was generated before it was used
>> does not need activity information - it can be asserted either in terms of
>> event ordering or temporal ordering. I believe we should remove
>> wasInformedBy or move it out of activity ordering section.
>>
>>
>>
> What do you mean by *clearly*?
> How can we assert this by event/temporal ordering ?
> 1. The relations precedes/follows do not belong to the data model (they
> are used in interpretation)
> 2. The interpretation over wasInformedBy is a necessary condition, not a
> sufficient condition.
>           There needs to be an entity used and generated between these
> activities, though we dont have to assert it.
>
>
>  2. "The relationship wasInformedBy is not transitive. Indeed, consider
>> the records wasInformedBy(a2,a1) and wasInformedBy(a3,a2), the record
>> wasInformedBy(a3,a1), may not necessarily hold, as illustrated by the
>> following event line."
>>
>> Comment: It is not clear from the description and the figure, why
>> wasInformedBy is not transitive? It is difficult to interpret the figure
>> without additional description.
>>
>>
>
> Tim mentioned this. THis will be dealt with.
>
>> 3. "Given two activity records identified by a1 and a2, the record
>> wasStartedBy(a2,a1) holds if and only if there exist an entity record
>> identified by e and some attributes gAttr and sAttr, such that
>> wasGeneratedBy(e,a1,gAttr) and wasStartedBy(a2,e,sAttr) hold."
>>
>> Comment: The above definition and related example for wasStartedBy are
>> not clear at all. What is meant by the statement that "spawn-request" was
>> generated by a1 and "spawn-request" is in a wasStartedBy relation with a2,
>> hence a1 and a2 also have a wasStartedBy relation? Is "spawn-request"
>> supposed to represent control message exchanged between a1 and a2 or
>> something else?
>>
>>
>
> There were problems in the text. I hopefully fixed them. Can you check?
>
> Luc
>
>> Thanks.
>>
>> Best,
>> Satya
>>
>>
>>
>>
>>
>
> --
> 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<http://www.ecs.soton.ac.uk/~lavm>
>
>
>
Received on Tuesday, 14 February 2012 22:55:22 GMT

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