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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 09:11:16 +0100
Message-ID: <4E2FC824.1050105@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 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 08:12:06 GMT

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