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

From: Graham Klyne <GK@ninebynine.org>
Date: Fri, 05 Aug 2011 08:12:12 +0100
Message-ID: <4E3B97CC.3050008@ninebynine.org>
To: Paulo Pinheiro da Silva <paulo@utep.edu>
CC: public-prov-wg@w3.org
Good point here, I think.  Given that a process execution *has happened* or *has 
been observed* in some context...


Paulo Pinheiro da Silva wrote:
> 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 07:13:01 UTC

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