- From: Khalid Belhajjame <Khalid.Belhajjame@cs.man.ac.uk>
- Date: Wed, 27 Jul 2011 09:11:16 +0100
- To: Satya Sahoo <satya.sahoo@case.edu>
- CC: Luc Moreau <L.Moreau@ecs.soton.ac.uk>, public-prov-wg@w3.org
- Message-ID: <4E2FC824.1050105@cs.man.ac.uk>
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 UTC