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Re: PROV-ISSUE-26 (uses and generates questions): How can one figure out the provenance of a given entity?

From: Paulo Pinheiro da Silva <paulo@utep.edu>
Date: Fri, 5 Aug 2011 01:03:47 -0600
Message-ID: <4E3B95D3.3030609@utep.edu>
To: <public-prov-wg@w3.org>
Hi Luc,

I would say that the thing that is deterministic or not is the recipe of 
the process and neither the process execution or the process itself. For 
example, a recipe can be deductive or inductive.

It is a dangerous proposition to allowing process executions to be 
labeled as deterministic or non-deterministic. For instance, let say 
that one process is defined by a deductive recipe. This means that every 
execution of this process needs to be deterministic. However, we cannot 
prevent one execution of a process A to be deterministic and another 
execution of A to be non-deterministic if we allow the representation to 
accommodate such inconsistencies.

Many thanks,
Paulo.


On 8/5/2011 12:42 AM, Luc Moreau wrote:
>
> Hi Jim and Reza,
>
> Jim's assumption is right.
> I am happy to mention (non)-determinism for PEs.
>
> Regards,
> Luc
>
> On 05/08/11 01:51, Reza B'Far wrote:
>> Makes sense.
>>
>> So, I suggest that we at least document that PE can be deterministic
>> or non-deterministic (both) so that it's not assumed that it is
>> deterministic... unless the majority here think this is obviated.
>>
>> On 8/4/11 5:42 PM, Myers, Jim wrote:
>>> I assume (always a bad idea :-)) that Luc means replay as in starting
>>> from the same input and running the same PE and checking to see if
>>> you get the same output. A lossy process would not be a problem since
>>> you have the original input, assuming you still have access. If the
>>> PE changes the image by rewriting the file, you’d at least have Bobs
>>> representing the file before and after and would know that you need
>>> access to the before-content to do replay. (Whether you have that
>>> version/back-up copy is out of scope).
>>>
>>> Another interesting replay question is if the PE is random/stochastic
>>> - a replay would not give the same result, but many replays would
>>> have some statistical relationship to each other. In either case, I
>>> think the provenance role is just to point to the Bobs and the PE so
>>> if you have access to the Bobs and understand what the PE is doing,
>>> you could try to replay. Going beyond that is probably out of scope...
>>>
>>>    Jim
>>>
>>>> -----Original Message-----
>>>> From: public-prov-wg-request@w3.org [mailto:public-prov-wg-
>>>> request@w3.org] On Behalf Of Reza B'Far
>>>> Sent: Thursday, August 04, 2011 7:40 PM
>>>> To: public-prov-wg@w3.org
>>>> Subject: Re: PROV-ISSUE-26 (uses and generates questions): How can
>>>> one figure
>>>> out the provenance of a given entity?
>>>>
>>>> Luc -
>>>>
>>>> You mention "you may want to replay the execution...".  Question
>>>> (and I hope
>>>> I'm not missing this conversation on a different thread) -
>>>>
>>>> Is Process Execution always lossless and linear in time? In other
>>>> words, is replay
>>>> always possible? (for example, can image compression be a process
>>>> execution
>>>> since the compression may be lossy?)  Either way, I think this is
>>>> important to
>>>> articulate since it'll have ramifications on how inference engines
>>>> decide
>>>> whether it's possible to "replay" and if the "replay" is exact or
>>>> approximate.
>>>>
>>>> Hope the question is not nonsensical.
>>>>
>>>> On 8/4/11 4:16 PM, Luc Moreau wrote:
>>>>> Hi Paulo,
>>>>>
>>>>> Using the notation we have introduced in the provenance model, this is
>>>>> writen
>>>>>
>>>>>
>>>>> uses(pe, a, r_a)
>>>>> uses(pe, b, r_b)
>>>>> isGeneratedBy(c,pe,r_c)
>>>>> isDerivedFrom(c,a)
>>>>>
>>>>> where a,b,c are entities, pe a process execution and r_a, r_b, r_c
>>>>> roles.
>>>>>
>>>>> To try and answer your questions:
>>>>> - if something is wrong about c, you may want to inspect pe, and
>>>>> hopefully
>>>>>      there are assertions about pe (not in this excerpt) which may be
>>>>> useful
>>>>>
>>>>> - you may want to replay the execution, and so having a and b, and
>>>>> knowing
>>>> which
>>>>>      process definition underping pe, may help you verify the result.
>>>>>
>>>>> - I assume you mean can we infer that c was derived by the process
>>>>> execution
>>>>>
>>>>>      Yes, this is explained in the document, and further refine in the
>>>>> soon-to-be-released new version.
>>>>>       Only one pe can generate c (in one account).
>>>>>       And from a derivation from c to a, one can infer the existence of
>>>>> a pe which generated c and  used a.
>>>>>
>>>>> I hope it helps,
>>>>> Cheers,
>>>>> Luc
>>>>>
>>>>> On 07/07/11 15:50, Provenance Working Group Issue Tracker wrote:
>>>>>> PROV-ISSUE-26 (uses and generates questions): How can one figure out
>>>>>> the provenance of a given entity?
>>>>>>
>>>>>> http://www.w3.org/2011/prov/track/issues/26
>>>>>>
>>>>>> Raised by: Paulo Pinheiro da Silva
>>>>>> On product:
>>>>>>
>>>>>> Context:
>>>>>> 1. P uses A
>>>>>> 2. P uses B
>>>>>> 3. P generates C
>>>>>> 4. C derived from A
>>>>>>
>>>>>> If the provenance of C is the concern of a user of C (as opposed to
>>>>>> the provenance of a process that generates C), one may have the
>>>>>> following
>>>> questions:
>>>>>> 1) What the “uses” and “generates” relationships are adding to one’s
>>>>>> understanding of C if something is wrong with C?
>>>>>> 2) Can we infer that A was derived by the execution of process P?
>>>>>> How?
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>
>
Received on Friday, 5 August 2011 07:04:04 UTC

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