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RE: PROV-ISSUE-26 (uses and generates questions): How can one figure out the provenance of a given entity?

From: Myers, Jim <MYERSJ4@rpi.edu>
Date: Thu, 4 Aug 2011 20:42:27 -0400
Message-ID: <B7376F3FB29F7E42A510EB5026D99EF20552A7FE@troy-be-ex2.win.rpi.edu>
To: <reza.bfar@oracle.com>, <public-prov-wg@w3.org>
I assume (always a bad idea :-)) that Luc means replay as in starting from the same input and running the same PE and checking to see if you get the same output. A lossy process would not be a problem since you have the original input, assuming you still have access. If the PE changes the image by rewriting the file, you’d at least have Bobs representing the file before and after and would know that you need access to the before-content to do replay. (Whether you have that version/back-up copy is out of scope).

Another interesting replay question is if the PE is random/stochastic - a replay would not give the same result, but many replays would have some statistical relationship to each other. In either case, I think the provenance role is just to point to the Bobs and the PE so if you have access to the Bobs and understand what the PE is doing, you could try to replay. Going beyond that is probably out of scope...

 Jim

> -----Original Message-----
> From: public-prov-wg-request@w3.org [mailto:public-prov-wg-
> request@w3.org] On Behalf Of Reza B'Far
> Sent: Thursday, August 04, 2011 7:40 PM
> To: public-prov-wg@w3.org
> Subject: Re: PROV-ISSUE-26 (uses and generates questions): How can one figure
> out the provenance of a given entity?
> 
> Luc -
> 
> You mention "you may want to replay the execution...".  Question (and I hope
> I'm not missing this conversation on a different thread) -
> 
> Is Process Execution always lossless and linear in time? In other words, is replay
> always possible? (for example, can image compression be a process execution
> since the compression may be lossy?)  Either way, I think this is important to
> articulate since it'll have ramifications on how inference engines decide
> whether it's possible to "replay" and if the "replay" is exact or approximate.
> 
> Hope the question is not nonsensical.
> 
> On 8/4/11 4:16 PM, Luc Moreau wrote:
> > Hi Paulo,
> >
> > Using the notation we have introduced in the provenance model, this is
> > writen
> >
> >
> > uses(pe, a, r_a)
> > uses(pe, b, r_b)
> > isGeneratedBy(c,pe,r_c)
> > isDerivedFrom(c,a)
> >
> > where a,b,c are entities, pe a process execution and r_a, r_b, r_c roles.
> >
> > To try and answer your questions:
> > - if something is wrong about c, you may want to inspect pe, and hopefully
> >    there are assertions about pe (not in this excerpt) which may be
> > useful
> >
> > - you may want to replay the execution, and so having a and b, and knowing
> which
> >    process definition underping pe, may help you verify the result.
> >
> > - I assume you mean can we infer that c was derived by the process
> > execution
> >
> >    Yes, this is explained in the document, and further refine in the
> > soon-to-be-released new version.
> >     Only one pe can generate c (in one account).
> >     And from a derivation from c to a, one can infer the existence of
> > a pe which generated c and  used a.
> >
> > I hope it helps,
> > Cheers,
> > Luc
> >
> > On 07/07/11 15:50, Provenance Working Group Issue Tracker wrote:
> >> PROV-ISSUE-26 (uses and generates questions): How can one figure out
> >> the provenance of a given entity?
> >>
> >> http://www.w3.org/2011/prov/track/issues/26

> >>
> >> Raised by: Paulo Pinheiro da Silva
> >> On product:
> >>
> >> Context:
> >> 1. P uses A
> >> 2. P uses B
> >> 3. P generates C
> >> 4. C derived from A
> >>
> >> If the provenance of C is the concern of a user of C (as opposed to
> >> the provenance of a process that generates C), one may have the following
> questions:
> >>
> >> 1) What the “uses” and “generates” relationships are adding to one’s
> >> understanding of C if something is wrong with C?
> >> 2) Can we infer that A was derived by the execution of process P? How?
> >>
> >>
> >>
> >>
> >

Received on Friday, 5 August 2011 00:42:59 UTC

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