RE: PROV-ISSUE-66 (is-execution-a-bob): Why is process execution not defined as a characterised entity? [Conceptual Model]

While I suspect that the potential symmetry that Simon is identifying is
'there', I would argue against making PE = Bob (or making them
subclasses of a common ancestor) from two angles:

The most compelling to me is just that I cannot see how we're going to
explain the model if we argue that what people typically think of as
objects and what they typical call processes are really not so
distinguishable. As I'll suggest below, I think we have ways to address
Simon's use cases if we have IVPof (and maybe participates) and I'm
hopeful we can argue for them without resorting to endurant/perdurant
arguments. (If we did make them the same, or subclasses of the same
thing (and we can find the Bob and PE that correspond via some
relation(s) in the model) , we would be adding a duplicate mechanism to
model their provenance...).


For those who want to do that, here's my take on the mapping: I think we
primarily have an endurant(Bob) - perdurant (PE) model - that's the
used/generatedby core of the model. In the spirit of "The Water Falls
But The Waterfall Does Not Fall", by Galton and Mizoguchi, though, pil
recognizes that things we think of as endurants can also have a
perdurant aspect when we consider other processes. An endurant egg that
goes into a cake baking process (endurant in the sense that at each
instant in time, it is indeed an egg), is also participating in a
'warming egg' process (perdurant in the sense that at no point in time
is the egg actually warming, participates implying that the endurant egg
is part of the substrate for the perdurant process). To model this, we
have IVPof which allows us to model the warming egg by talking about the
cold egg (endurant), the heating process (perdurant), and the warm egg
(endurant). What we don't have in the model is the 'warming egg'
directly - no way to say energy went into a 'warming egg' without
identifying the 'heating process' separately and saying energy and the
'cold egg' were inputs.

Philosophy aside, I think it is true that IVPof and participates (in the
sense used here - not sure where the group debate has settled on
pil:participates) allows us to cover all of the use cases where you
might want to talk about the perdurant aspects of an endurant Bob or the
endurant aspects of a perdurant PE. A PE's provenance would be complete
if one described the provenance of all inputs (used) and the provenance
of all Bobs that 'participate in'/are the substrate for the PE. A Bob's
provenance would be complete if one described the PE that generated it
and all of the PEs it had "participated in".

So - hopefully the discussion here helps. If not, my basic sense is that



> -----Original Message-----
> From: public-prov-wg-request@w3.org [mailto:public-prov-wg-
> request@w3.org] On Behalf Of Luc Moreau
> Sent: Monday, August 01, 2011 6:50 AM
> To: public-prov-wg@w3.org
> Subject: Re: PROV-ISSUE-66 (is-execution-a-bob): Why is process
execution
> not defined as a characterised entity? [Conceptual Model]
> 
> Hi Simon,
> 
> While I mentioned, endurant/perdurant, I was using them for intuition,
and
> didn't mean to formally introduce them in the definition.
> You may be right, a BOB with temperature changing constantly, may not
fit
> the endurant/perdurant distinction. But I am not expert in this
ontology.
> 
> But, I don't see why this makes a case for PE=BOB. What use case do
you try
> to resolve by merging the two concepts?  Its major downside is the
unknown
> meaning of using/generating a process execution.  It seems also to mix
> use/generation/start/end.
> 
> I see a process execution as a set of events using/generating BOBs,
and
> temporally delimited by a start and end event.  This set of event is
said  by
> an asserter to be an identifiable activity.
> This activity has an "effect" on the world, by all the BOBs it
generates.
> 
> So can you identify an example that we can't model with  PE<>BOB but
can
> with PE=BOB?
> 
> Luc
> 
> On 08/01/2011 11:09 AM, Simon Miles wrote:
> > Hi Luc,
> >
> > OK, I believe I understand your intuition, but would argue:
> >
> > 1. A process execution currently fits the definition of a BOB, as it
> > has assertable characteristics, is identifiable, and is an entity,
> > i.e. bounded.
> >
> > 2. I was not clear we wanted to restrict BOBs to endurants. For
> > example, at the F2F1, Tim raised the case of expressing that
something
> > changed temperature by 10 degrees (and why), without asserting what
> > the start and end temperatures were. If I remember correctly, you
and
> > I argued that the temperature change could be seen as an (invariant)
> > attribute of a BOB, because BOBs are not necessarily instantaneous.
> > And if I understand endurants and perdurants correctly, I think the
> > change is a perdurant because at any moment, the change itself is
not
> > apparent.
> >
> > Intuitively, it seems reasonable that a process execution is
something
> > you can ask the provenance of ("why did this execution occur as it
> > did?"). This might or might not be fully answered by saying what the
> > execution used, who it was controlled by, when it started, and what
> > recipe it followed.
> >
> > I recognise that it makes things complicated, in that a process
> > execution (as a BOB) could be "generated" or "used" by another
> > execution, but perhaps this is what we mean by the "ordering of
> > processes" concept anyway. The existing definition "Generation
> > represents the creation of a new characterized entity by an
activity.
> > This characterized entity did not exist before creation." seems to
fit
> > the notion of one process starting another one quite nicely.
> >
> > To be more constructive, here's my counter-proposal.
> >
> > * We add "characterized entity" to the process execution definition,
> > e.g. "A process execution represents an activity which performs a
> > piece of work. An activity is a kind of identifiable characterized
> > entity."
> >
> > No other change seems necessary, though some explanation of the
> > consequences may be needed. We might then have also covered
"ordering
> > of processes", at least in a causal sense (temporal ordering is
> > different).
> >
> > Thanks,
> > Simon
> >
> > On 1 August 2011 09:14, Luc Moreau<L.Moreau@ecs.soton.ac.uk>  wrote:
> >
> >> Hi Simon,
> >>
> >> To me, process executions are the "verbs", whereas BOBs are the
> >> "nouns", and therefore belong to different categories.
> >>
> >> Several people have also mentioned they relate to
perdurant/endurant
> >> in formal ontologies.
> >>
> >> Being identifiable is therefore not the key characteristic!
> >>
> >> Regards,
> >> Luc
> >>
> >>
> >> PS. In a separate thread, you mentioned that IVPof could be used
for
> >> process executions.
> >>     This may make sense, but in that case we simply need to change
> >> the signature of IVP of:
> >>          BOB x BOB   U   PE x PE
> >>
> >>
> >>
> >> On 07/29/2011 05:22 PM, Provenance Working Group Issue Tracker
> wrote:
> >>
> >>> PROV-ISSUE-66 (is-execution-a-bob): Why is process execution not
> >>> defined as a characterised entity? [Conceptual Model]
> >>>
> >>> http://www.w3.org/2011/prov/track/issues/66
> >>>
> >>> Raised by: Simon Miles
> >>> On product: Conceptual Model
> >>>
> >>> This was mentioned by Satya in the call, but I can't see it having
been
> raised as an issue yet.
> >>>
> >>> As process executions are identified and may have attributes,
including
> start and end time, are they kinds of characterised entities,
similarly to
> agent? If not, why not?
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>
> >> --
> >> 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
> >>
> >>
> >>
> >>
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> >>
> >
> >
> >
> 
> --
> 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 Monday, 1 August 2011 15:38:15 UTC