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

Hi Luc,

To clarify, I (and Satya, I believe) was not suggesting PE=BOB, just
that PE is a subclass of BOB.

> 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.

I can see no problem with all the above.

> Its major downside is
> the unknown meaning of using/generating a process execution.  It seems
> also to mix use/generation/start/end.

I think it is just that "use" and "generation" make sense when we are
thinking of a PE as a general BOB, while start/end make sense when we
are looking at it specifically as a PE. Same as for agent, where
"controlled" only makes sense when seeing it as an agent specifically.

Interpreting generation at least, seems clear enough. "Generation
represents the creation of a new characterized entity by an activity.
This characterized entity did not exist before creation." If the "new
charactized entity" happens to be a actviity, then it means one
activity has created another activity. That suggests that the
action/event of generation = the start of the created execution.

Use may be harder, as I'm not sure what "consumption" of a process
execution would denote from the definition "Use represents the
consumption of a characterized entity by an activity." However, I'm
not clear what the implications of "consuming" a document are either.
I think this just requires clarifying what "consuming a BOB" is
intending to mean (a separate issue).

> So can you identify an example that we can't model with  PE<>BOB
> but can with PE=BOB?

I give it a go below, but even if this doesn't convince you and my
counter-proposal was rejected, I still think the issue needs
addressing somehow.

To extend the File Scenario, we want to express the provenance of the
first "copy" process execution, pe2.
  processExecution(pe2,copy,t+2)

Why did it come about? This seems not the same as saying what data it
used or who "controlled" it, it is because Charles typed some text
into a console at pressed return, which we can express as:
  processExecution(pe7,command-typed,t+1.8)

By my proposal, this would automatically imply (as is already done for
"agent(x)"):
  bob(e7)

Now we can express that pe2, as a BOB, owes its existence to pe7.
  isGeneratedBy(pe7,pe2,out)

Why would we want to consider expressing the above? Perhaps we want to
assert that Charles was typing the  commands on a small mobile device,
which is why the email address was mistyped and the document (e4)
failed to reach its intended recipient.

Thanks,
Simon

On 1 August 2011 11:50, Luc Moreau <L.Moreau@ecs.soton.ac.uk> wrote:
> 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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>



-- 
Dr Simon Miles
Lecturer, Department of Informatics
Kings College London, WC2R 2LS, UK
+44 (0)20 7848 1166

Received on Monday, 1 August 2011 11:40:25 UTC