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Re: PROV-ISSUE-43 (derivation-time): Deriviation should have associated time [Conceptual Model]

From: Khalid Belhajjame <Khalid.Belhajjame@cs.man.ac.uk>
Date: Wed, 27 Jul 2011 19:55:25 +0100
Message-ID: <4E305F1D.3060301@cs.man.ac.uk>
To: Satya Sahoo <satya.sahoo@case.edu>
CC: Luc Moreau <L.Moreau@ecs.soton.ac.uk>, public-prov-wg@w3.org
Hi Satya,

On 27/07/2011 18:24, Satya Sahoo wrote:
> Hi Khalid,
> >I don't think that such a rule was suggested to infer new 
> information. It was merely used to clarify what the time t >refers to 
> in the assertion isDerivedFrom(b1,b2,t), i.e., whether t refers to the 
> time in which the process execution >that generates b2 use b1, or the 
> time at which the process in question generates b2.
> I am not sure we can infer anything about the time at which a process 
> uses b1 from isDerivedFrom(b1, b2, t) - one explanation of the 
> assertion isDerivedFrom(b1, b2, t) can be that b1 "starts existing" at 
> t and we know that b1 was derived from b2, hence we can say that b1 
> was derived from b2 at t. Extending this interpretation, we may in 
> some cases, where we know about the process that generated b1, that 
> process generated b1 at t.
>
> The above explanation can be stated as the following rule:
> if isDerivedFrom (b1, b2, t) and isGeneratedBy(b1, pe) then 
> isGeneratedBy(b1, pe, t).

Agreed, assuming that t in isDerivedFrom (b1, b2, t) refers to the time 
at which b1 was created.

Khalid

>
> Thanks.
>
> Best,
> Satya
>
> On Wed, Jul 27, 2011 at 4:11 AM, Khalid Belhajjame 
> <Khalid.Belhajjame@cs.man.ac.uk 
> <mailto:Khalid.Belhajjame@cs.man.ac.uk>> wrote:
>
>
>     Hi Satya,
>
>
>     On 26/07/2011 19:26, Satya Sahoo wrote:
>>     Hi Khalid,
>>     >  No information about the process pe is inferred. The above
>>     merely specifies that there exists a process >execution, (which
>>     we don't know), such that isGeneratedBy(e1,pe,r1) and use(pe,e0,r0)
>>     If we do not know about pe, then what new knowledge is being
>>     added to the provenance store using the above rule?
>>
>
>     I don't think that such a rule was suggested to infer new
>     information. It was merely used to clarify what the time t refers
>     to in the assertion isDerivedFrom(b1,b2,t), i.e., whether t refers
>     to the time in which the process execution that generates b2 use
>     b1, or the time at which the process in question generates b2.
>
>     Thanks, khalid
>
>
>>     The information that a pe may exist anyway follows from our 'open
>>     world assumption'.
>>
>>     > IMO, we cannot make this inference. The process execution pe
>>     may well generate e1 without using e0, even if >e0 is an input of
>>     that process execution.
>>     I agree with your point - there may be an indirect dependency
>>     between e1 and e0 (if pe cannot be executed without e0 being
>>     present). But, defining the indirect dependency as
>>     the isGeneratedBy property may be inaccurate.
>>
>>     Thanks.
>>
>>     Best,
>>     Satya
>>
>>
>>     On Tue, Jul 26, 2011 at 4:26 AM, Khalid Belhajjame
>>     <Khalid.Belhajjame@cs.man.ac.uk
>>     <mailto:Khalid.Belhajjame@cs.man.ac.uk>> wrote:
>>
>>
>>         Hi Satya,
>>
>>         On 26/07/2011 02:33, Satya Sahoo wrote:
>>>         Hi Luc,
>>>         >  I think there is a missing "inference" in the specification.
>>>         >If there isDerivedFrom(e1,e0) holds, then there exists a
>>>         process execution pe, and roles r0,r1, such that:
>>>         >isGeneratedBy(e1,pe,r1) and use(pe,e0,r0)
>>>
>>>         I am not sure how can we infer additional information (pe,
>>>         r0, r1) from limited information (e1, e0)? Did you mean, we
>>>         have the information about pe, r0, r1, and the link between
>>>         them and (e1, e0) already stored somewhere?
>>
>>         No information about the process pe is inferred. The above
>>         merely specifies that there exists a process execution,
>>         (which we don't know), such that isGeneratedBy(e1,pe,r1) and
>>         use(pe,e0,r0)
>>
>>
>>>
>>>         As an alternate, I think we can define the inference rule in
>>>         the opposite direction:
>>>         if there exists: isGeneratedBy(e1,pe,r1) and use(pe,e0,r0)
>>>         then: isDerivedFrom(e1,e0) holds true?
>>
>>         IMO, we cannot make this inference. The process execution pe
>>         may well generate e1 without using e0, even if e0 is an input
>>         of that process execution.
>>
>>         Thanks, khalid
>>
>>
>>>
>>>         Also, if we consider the above alternate version of the
>>>         rule, we need to define whether isDerivedFrom "existentially
>>>         dependent" on "isGeneratedBy" and "use" properties, in other
>>>         words only if isGeneratedBy(e1,pe,r1) AND use(pe,e0,r0)
>>>         already exist can we have isDerivedFrom(e1,e0)? Or,
>>>         isDerivedFrom can be independently asserted?
>>>
>>>         Best,
>>>         Satya
>>>
>>>         On Mon, Jul 25, 2011 at 4:21 AM, Luc Moreau
>>>         <L.Moreau@ecs.soton.ac.uk <mailto:L.Moreau@ecs.soton.ac.uk>>
>>>         wrote:
>>>
>>>
>>>
>>>             I'd like to refer to the missing inference I mentioned
>>>             in a separate thread:
>>>
>>>             I think there is a missing "inference" in the specification.
>>>
>>>             If there isDerivedFrom(e1,e0) holds, then there exists a
>>>             process execution pe, and roles r0,r1,
>>>             such that:
>>>              isGeneratedBy(e1,pe,r1) and use(pe,e0,r0)
>>>
>>>
>>>             So, given isDerivedFrom(e1,e0), I would argue that there
>>>             are potentially four
>>>             notions of time associated with this derivation:
>>>             - beginning of pe
>>>             - end of pe
>>>             - use of e0
>>>             - generation of e1
>>>
>>>             Paul, in your proposal, were you referring to any of
>>>             these 4 instants, or
>>>             did you have another notion of time not captured yet?
>>>
>>>
>>>             Luc
>>>
>>>
>>>
>>>             On 07/24/2011 09:12 PM, Paul Groth wrote:
>>>
>>>                 Something like that...I need to look at the exact
>>>                 definition of derived from.
>>>
>>>                 Paul
>>>
>>>                 On Jul 24, 2011, at 20:43, Khalid
>>>                 Belhajjame<Khalid.Belhajjame@cs.man.ac.uk
>>>                 <mailto:Khalid.Belhajjame@cs.man.ac.uk>>  wrote:
>>>
>>>
>>>
>>>                     Ok, I must admit I didn't understand that. Just
>>>                     to clarify, when one say
>>>                     isDerivedFrom(b1,b2,t), does that means that b2
>>>                     was created at t?
>>>
>>>                     Thanks, khalid
>>>
>>>
>>>                     On 24/07/2011 18:33, Paul Groth wrote:
>>>
>>>                         Hi Khalid,
>>>
>>>                         I don't think this is what I mean.
>>>
>>>                         It's not when the assertion was made. It's
>>>                         when the derivation occurred according to
>>>                         the asserter.
>>>
>>>                         Just as with use and generation. It's the
>>>                         time at which these events occur according
>>>                         to the asserter.
>>>
>>>                         Thanks
>>>                         Paul
>>>
>>>                         On Jul 24, 2011, at 18:08, Khalid
>>>                         Belhajjame<Khalid.Belhajjame@cs.man.ac.uk
>>>                         <mailto:Khalid.Belhajjame@cs.man.ac.uk>>  
>>>                         wrote:
>>>
>>>
>>>                             On 24/07/2011 15:35, Myers, Jim wrote:
>>>
>>>                                 (The time is not the interval over
>>>                                 which the derivation relation is
>>>                                 valid - in the same way the time on
>>>                                 USED is not the time when that
>>>                                 relation is valid (it would be if
>>>                                 the semantics were 'in use during
>>>                                 interval t') - both just describe
>>>                                 the time when an enduring relationship
>>>                                 was first formed.)
>>>
>>>                             Agreed, that what I was hinting to in my
>>>                             last response email to Paul.
>>>                             The time I was referring to in my email
>>>                             was the validity, but Paul, I
>>>                             think, was talking about the time where
>>>                             the derivation was formed.
>>>
>>>                             Which leads me to a new proposal.
>>>                             Instead of having the time as argument
>>>                             to USE, GENERATION and derivation, e.g.,
>>>                             isDerivedFrom(b1,b2,t). Would
>>>                             it be sensible to assume, instead, that
>>>                             every assertion may be
>>>                             associated with a time in which it was
>>>                             formed?
>>>
>>>                             Thanks, Khalid
>>>
>>>
>>>                                  Jim
>>>
>>>
>>>                                     -----Original Message-----
>>>                                     From:
>>>                                     public-prov-wg-request@w3.org
>>>                                     <mailto:public-prov-wg-request@w3.org>
>>>                                     [mailto:public-prov-wg-
>>>                                     <mailto:public-prov-wg->
>>>                                     request@w3.org
>>>                                     <mailto:request@w3.org>] On
>>>                                     Behalf Of Khalid Belhajjame
>>>                                     Sent: Sunday, July 24, 2011 8:27 AM
>>>                                     To: Paul Groth
>>>                                     Cc: Provenance Working Group WG;
>>>                                     Provenance Working Group Issue
>>>
>>>                                 Tracker
>>>
>>>                                     Subject: Re: PROV-ISSUE-43
>>>                                     (derivation-time): Deriviation
>>>                                     should have
>>>                                     associated time [Conceptual Model]
>>>
>>>
>>>                                     Hi Paul,
>>>
>>>                                     On 24/07/2011 13:13, Paul Groth
>>>                                     wrote:
>>>
>>>                                         Hi Khalid
>>>                                         But why can't I say that a
>>>                                         newspaper article is derived
>>>                                         from a
>>>
>>>                                 picture at a
>>>
>>>                                     particular time? Or for that
>>>                                     matter over a period of time.
>>>
>>>                                     The way I see it, is that there
>>>                                     will be a bob representing the
>>>
>>>                                 newspaper article
>>>
>>>                                     and another representing the
>>>                                     picture. If there is evidence
>>>                                     that the
>>>
>>>                                 latter is
>>>
>>>                                     derived from the former, then
>>>                                     the derivation will always hold
>>>                                     between
>>>
>>>                                 those
>>>
>>>                                     two bobs.
>>>
>>>                                     Now, that I am writing this
>>>                                     email, I am wondering whether we are
>>>
>>>                                 referring to
>>>
>>>                                     the same notion of time. In your
>>>                                     statement, isDerivedFrom(b1,b2,t), I
>>>
>>>                                 think you
>>>
>>>                                     mean t is used to refers to the
>>>                                     time in which the derivation
>>>                                     assertion
>>>
>>>                                 was
>>>
>>>                                     made, whereas what I was
>>>                                     thinking of is the (period of)
>>>                                     time in which
>>>
>>>                                 the
>>>
>>>                                     derivation holds. Is that the case?
>>>
>>>                                     Thanks, khalid
>>>
>>>                                         The time is when the
>>>                                         derivation occurred not when
>>>                                         it applies.
>>>
>>>                                         Thanks
>>>                                         Paul
>>>
>>>                                         On Jul 24, 2011, at 13:06,
>>>                                         Khalid
>>>
>>>                                     Belhajjame<Khalid.Belhajjame@cs.man.ac.uk
>>>                                     <mailto:Khalid.Belhajjame@cs.man.ac.uk>>
>>>                                         wrote:
>>>
>>>                                             Hi Paul,
>>>
>>>                                             I think that "Use" and
>>>                                             "Generation" should be
>>>                                             associated with time.
>>>                                             However, I don't think
>>>                                             we should associate time
>>>                                             to derivation.
>>>                                             I would argue that
>>>                                             isDerivedFrom(b1,b2)
>>>                                             holds all time. Although b1
>>>                                             and
>>>                                             b2 may no longer exist,
>>>                                             isDerivedFrom(b1,b2) is
>>>                                             still valid.
>>>
>>>                                             Thanks, khalid
>>>
>>>
>>>                                             On 23/07/2011 16:46,
>>>                                             Provenance Working Group
>>>                                             Issue Tracker wrote:
>>>
>>>                                                 PROV-ISSUE-43
>>>                                                 (derivation-time):
>>>                                                 Deriviation should have
>>>
>>>                                 associated
>>>
>>>                                                 time [Conceptual Model]
>>>
>>>                                                 http://www.w3.org/2011/prov/track/issues/43
>>>
>>>                                                 Raised by: Paul Groth
>>>                                                 On product:
>>>                                                 Conceptual Model
>>>
>>>                                                 Other relationships
>>>                                                 have time associated
>>>                                                 with them (e.g. use,
>>>                                                 generation, control)
>>>
>>>                                                 There is no optional
>>>                                                 time associated with
>>>                                                 derivation.
>>>
>>>                                                 Suggested resolution
>>>                                                 is to add the
>>>                                                 following to the
>>>                                                 definition of
>>>
>>>                                     isDerivedFrom:
>>>
>>>                                                 -  May contain a
>>>                                                 "derived from time"
>>>                                                 t, the time or time
>>>                                                 intervals
>>>                                                 when b1 was derived
>>>                                                 from b2
>>>
>>>                                                 Example:
>>>                                                 isDerivedFrom(b1,b2, t)
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>             -- 
>>>             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>
>>>
>>>
>>>
>>
>>
>
>
Received on Wednesday, 27 July 2011 18:56:03 GMT

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