- From: James Cheney <jcheney@inf.ed.ac.uk>
- Date: Thu, 9 Aug 2012 10:59:00 +0100
- To: Stian Soiland-Reyes <soiland-reyes@cs.manchester.ac.uk>
- Cc: Luc Moreau <l.moreau@ecs.soton.ac.uk>, public-prov-wg@w3.org
Sounds good to me. To be clear, is it correct to say that the options are: 1. [status quo] - allow expanding the trigger parameter to an existential variable denoting an unknown (but definite) trigger entity 2. change the trigger parameter to be non-expandable, so that "-" means "absent trigger", as with plan and other non-expandables. So we'll resolve this issue by taking whichever of the above has the stronger consensus? --James On Aug 9, 2012, at 10:55 AM, Stian Soiland-Reyes wrote: > I've given this a thought over night, I think that for the purpose of > LC, we can close this issue, if we just do a strawman poll in today's > meeting over whether it is OK to require activity start/end to have > triggers. (which I would vote 0 for) > > > On Wed, Aug 8, 2012 at 10:54 AM, Stian Soiland-Reyes > <soiland-reyes@cs.manchester.ac.uk> wrote: >> On Wed, Aug 8, 2012 at 9:51 AM, Luc Moreau <l.moreau@ecs.soton.ac.uk> wrote: >> >>> Can you explain what you mean by activities that just 'are'? >>> Do you mean they have no cause? Or don't know the cause? >> >> An activity in PROV might be a description of an observed process, >> rather than a record of a pre-planned activity which is already >> understood. What I interpret as a process depend on my assumptions of >> what constitutes the system, etc. So if I observe that a flock of >> birds start flying together as a single swarm, I can say that >> swarmFlying started at 11:58 and ended at 12:04. >> >> However, swarm flying is not 'caused' by anything, it is just an >> observed pattern where we see multiple birds moving in unison. Forcing >> this to have triggers means we have to invent trigger entities like >> "coherentProximitiesBetweenBirds" and "avoidanceRules" which we then >> need to explain the origin of. But any provenance trace is limited by >> its selected boundaries of assumptions, observations and view of the >> world; hence there would be statements which we don't make, which >> would go 'beyond' the chosen scope. For instance in the provenance for >> the Olympics world records, we might not include the position of the >> moon, although it would have affected the particular tide level in the >> river during the rowing event. >> >> Similarly, a shop keeper might see 10 customers in a row buy the same >> chocolate. What triggered this :chocolateBuying activity? Was there a >> commercial for this chocolate? Did the shop put up a nice poster? We >> humans are insisting on finding justifications for everything, but >> sometimes it might just be random behaviour - this particular day, 10 >> people, choosing independently for different reasons, just happened to >> all chose the same chocolate. So your activity is 'triggered' by your >> own definition of it. >> >> (I know this is dangerous waters, because this argument applies to >> entities as well; it might just be the observers particular >> characterisation that 'forms' a particular entity, and no activity for >> wasGeneratedBy can be found). >> >> >>> I am concerned about suddenly making triggers non-expandable >>> (i.e. not replaceable by existential variables) because we don't know >>> the implications of that change. >> >> I understand that. I am not giving a blank -1 to requiring triggers, >> but I wonder if the WG has agreed on them being required to exist >> (although they might not be stated). If we find another solution to my >> infinite loop, I can reluctantly let them stay, although I must admit >> I find them quite artificial in some circumstances. >> >> >> It is a worry that as we moved 'all the difficult bits' from PROV-DM >> into PROV-Constraints, many of the issues that earlier caused heated >> discussion has been silenced away, to be decided by two editors in >> private discussions. I am not trying to reheat those kind of >> discussions, but I am just concerned if those have been cut short >> rather than been settled and agreed. >> >> -- >> Stian Soiland-Reyes, myGrid team >> School of Computer Science >> The University of Manchester > > > > -- > Stian Soiland-Reyes, myGrid team > School of Computer Science > The University of Manchester > > -- The University of Edinburgh is a charitable body, registered in Scotland, with registration number SC005336.
Received on Thursday, 9 August 2012 09:59:51 UTC