- From: Luc Moreau <L.Moreau@ecs.soton.ac.uk>
- Date: Tue, 17 Jan 2012 11:24:23 +0000
- To: public-prov-wg@w3.org
Hi Paul, Still trying to tackle this outstanding issue. what are your views on this last message? Thanks, Luc On 11/30/2011 02:39 PM, Luc Moreau wrote: > Hi Paul, > > Trying to come back to this issue, now that we have revised the notion > of derivation. > > While I am sympathetic to the idea of "short-cuts" to facilitate life > of asserters, > I am also keen to stick to some (unwritten) design principles. > > 1. There should be one and only one place where a given piece of > information can > be placed in the data model. Failing to do so, then, asserters > won't know where to > assert information. Furthermore, the data model will have to > specify what it means > when places for a given piece of information contain different values. > > In this case, derivation time(=generation time) could be placed in > a derivation and in > a generation record. > > 2. Uniformity. If we make this time optional in derivation, we should > also make it on > "specializations" of derivation such as wasSummaryOf etc. > We don't do it. > > Ultimately, writing a derivation time (=generation time) requires > precision. > We shouldn't do it with an imprecise record. In the new terminology, > were you suggesting > to do have this option in imprecise-1 records? imprecise-n? > > Luc > > On 11/11/2011 04:26 PM, Luc Moreau wrote: >> Hi Paul, >> Remember that the activity may have been a long running service, >> which started well before the entity was used, >> and vice-versa, it could have ended well after the other entity was >> generated. >> >> Let us know what event you choose, and we'll encode this. >> Luc >> >> On 11/11/2011 15:52, Paul Groth wrote: >>> Hi Luc, >>> >>> Ok, I see what your asking. I think we can reuse the events. My >>> general thought is that (at 10 am) applies to the activity (e.g. the >>> anonymous activity that used the report). So that would map to >>> either the start or end of the activity or both? >>> >>> I'm not sure what's nicest. >>> >>> Thanks, >>> Paul >>> >>> Luc Moreau wrote: >>>> Hi Paul, >>>> >>>> Comments interleaved. >>>> >>>> On 11/09/2011 08:53 AM, Paul Groth wrote: >>>>> Hi Luc, >>>>> >>>>> For me this is about, saying the following: >>>>> >>>>> blogpost wasDerivedFrom Report at 10am Thursday >>>> >>>> What do you mean by this: blogpost was generated at 10am? >>>> >>>>> Sure there is some process there, there may be an interval. But I >>>>> just >>>>> don't want to assert all that information. >>>> >>>> I understand, but ultimately, I am trying to determine whether >>>> there is >>>> a new special event 'derivation' to which >>>> time is associated with, or whether we can reuse generation/use events >>>> or start/end events. >>>> >>>>> Again, my fundamental thing is that I want to assert derivation >>>>> chains >>>>> without (knowingly) asserting anything about process. >>>>> >>>>> Maybe the point is I'm looking for a shortcut such that if I assert a >>>>> time it automagically infers that the e2, and e1 are on the same time >>>>> line using the same clock and are the same time? >>>> >>>> Inferring time line and same clock would be no good. >>>> >>>>> Does that make sense? >>>>> >>>> >>>> I still need you to clarify the intended semantics, specifically, what >>>> notion of time you refer to. >>>> Then, when it's decided, we can express the short cut. >>>> >>>> My take on it, in the above example, you refer to the blogpost >>>> generation time. >>>> >>>>> Paul >>>> >>>> Luc >>>>> Luc Moreau wrote: >>>>>> Hi Paul, >>>>>> >>>>>> I'd like to come back to this issue, and see how we can solve it. >>>>>> >>>>>> The fully expanded notion of derivation, written >>>>>> wasDerivedFrom(e2,e1,pe,q2,q1), >>>>>> refers to the generation event for e2, and the use event for e1. >>>>>> So, they form an "interval". If we have time information for >>>>>> each of these events (and assuming a same clock), we can compute the >>>>>> duration >>>>>> of this interval. >>>>>> >>>>>> So, the question is, do you really have a use case, where you >>>>>> don't want >>>>>> to assert the use/generation events (qualified usage/generation) but >>>>>> want >>>>>> to express time? Can you explain it? >>>>>> >>>>>> My concern is that we are at risk of introducing two placeholders >>>>>> for >>>>>> the same time information >>>>>> (in derivation or use/generation events). Two placeholders for >>>>>> time may >>>>>> result in inconsistent >>>>>> information. >>>>>> >>>>>> Luc >>>>>> >>>>>> >>>>>> On 07/23/2011 04:46 PM, 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 University of Southampton fax: +44 23 8059 2865 Southampton SO17 1BJ email: l.moreau@ecs.soton.ac.uk United Kingdom http://www.ecs.soton.ac.uk/~lavm
Received on Tuesday, 17 January 2012 11:24:59 UTC