- From: Luc Moreau <L.Moreau@ecs.soton.ac.uk>
- Date: Tue, 02 Aug 2011 00:13:14 +0100
- To: public-prov-wg@w3.org
Hi Simon,
Response interleaved.
On 01/08/11 17:18, Simon Miles wrote:
> Hi Luc, Jim,
>
> Luc:
>
>> We still haven't defined process ordering, and I would argue that
>> ... We haven't had time to define this in spec. Sorry.
>>
> OK. I'm not certain having a signal from one execution to another is
> the same as one creating another, but am happy to leave this debate if
> you think it is not for this draft.
>
>
Hopefully, we'll write something by end of the week.
This said, I have looked at starting/ending process execution
as control, rather than process ordering (a la opm:wasTriggeredBy).
> But surely there still needs to be some resolution to the issue
> itself? The model implies (or is at least very easy to read as
> implying) that a PE is a kind of BOB, by the fact that a PE as defined
> fits the definition of a BOB. But if this is not intended, then what
> should the OWL file contain to reflect the model accurately? Again, I
> believe this was Satya's point, but he should probably clarify
> himself.
>
Why not simply: BOB owl:isDisjointWith ProcessExecution?
Luc
> [ To justify the importance of clarifying this in the model, I was
> working with someone last week who was using OPM and had expressed
> things in their application as artifacts that I would intuitively
> considered processes. They saw the final report on each process as
> their only knowledge of it, and those reports are static, so the
> processes were modelled as artifacts but with the names and reported
> characteristics of the processes. ]
>
> Jim, if I understand your argument correctly, you are saying that:
> - we should redefine PE/BOB to ensure a PE is not a BOB
> - we should define a relation from a PE to its 'substrate(s)', which are BOBs
> - describing the provenance of these substrates (along with
> everything else PIL can already say) completes the description of the
> provenance of a PE
>
> Is that correct? If so, I can buy that, but I'm not yet clear what
> that would look like in the model document, or if you are saying it is
> already as such in the document.
>
> Thanks,
> Simon
>
> On 1 August 2011 16:38, Myers, Jim<MYERSJ4@rpi.edu> wrote:
>
>> 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
>>>
>>>
>>
>>
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>
>
>
Received on Monday, 1 August 2011 23:13:51 UTC