- From: Khalid Belhajjame <Khalid.Belhajjame@cs.man.ac.uk>
- Date: Tue, 26 Jul 2011 09:26:22 +0100
- To: Satya Sahoo <satya.sahoo@case.edu>
- CC: Luc Moreau <L.Moreau@ecs.soton.ac.uk>, public-prov-wg@w3.org
- Message-ID: <4E2E7A2E.9000905@cs.man.ac.uk>
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 Tuesday, 26 July 2011 08:26:57 UTC