- From: Luc Moreau <L.Moreau@ecs.soton.ac.uk>
- Date: Fri, 05 Aug 2011 07:42:08 +0100
- 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