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

From: Luc Moreau <L.Moreau@ecs.soton.ac.uk>
Date: Fri, 05 Aug 2011 07:42:08 +0100
Message-ID: <EMEW3|57d2f6a91becfb7b6d1d8ca5939cdad0n747gF08L.Moreau|ecs.soton.ac.uk|4E3B90C0.5030601@ecs.soton.ac.uk>
To: public-prov-wg@w3.org

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 06:42:55 UTC

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