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Re: PROV-ISSUE-150: question on formal semantics of role in wasGeneratedBy relation [Formal Semantics]

From: Stephan Zednik <zednis@rpi.edu>
Date: Wed, 21 Dec 2011 11:12:46 -0700
Cc: Provenance Working Group WG <public-prov-wg@w3.org>
Message-Id: <BB004E62-4D8C-42C4-8AD7-D4DC127F4572@rpi.edu>
To: Simon Miles <simon.miles@kcl.ac.uk>
Hi Simon, Luc,

I believe that Tim and I are in agreement on this issue.  

I raised the issue because there was some discussion about Activities having roles in a PROV-O telecon (this was several weeks ago) and that conflicted with the existing definition of role.  I was also curious if there would be any objection to the assertion that a generated entity has a function in the activity that generates it.

Time's responses, and the lack of any further responses has led me to believe that:

1) The general understanding of the usage of roles in a qualified wasGeneratedBy fits the existing definition for roles, and I have not seen any further discussion of activities having roles.

2) There is general agreement (based on the lack of objections) that a generated entity can play a part/function in the activity that generates it.

I believe this issue can be closed.

--Stephan

On Dec 21, 2011, at 4:13 AM, Simon Miles wrote:

> Hi Stephan, Tim,
> It seems this discussion has different aspects relating to PROV-O,
> PROV-DM and the primer.
> 
> Could one of you raise the proposed changes to the primer with
> rationale as a separate issue specifically for that document? The
> "outputAggregatedDataset" naming suggestion makes sense to me and
> seems a good idea, but I'm not clear on the rationale behind the
> typing suggestion, so would be good if you can spell it out.
> 
> Thanks,
> Simon
> On 21 December 2011 10:42, Luc Moreau <L.Moreau@ecs.soton.ac.uk> wrote:
>> Hi Stephan and Tim,
>> 
>> Have we converged on this issue? Is there something that needs to be
>> addressed in the
>> prov-dm document?
>> 
>> If yes, can you clarify? If not, then I propose we close the issue.
>> 
>> Regards,
>> Luc
>> 
>> 
>> On 11/22/2011 04:25 PM, Timothy Lebo wrote:
>> 
>> 
>> On Nov 14, 2011, at 5:23 PM, Provenance Working Group Issue Tracker wrote:
>> 
>> 
>> PROV-ISSUE-150: question on formal semantics of role in wasGeneratedBy
>> relation [Formal Semantics]
>> 
>> http://www.w3.org/2011/prov/track/issues/150
>> 
>> Raised by: Stephan Zednik
>> On product: Formal Semantics
>> 
>> I am slightly confused about the formal semantics of the role qualifier in a
>> wasGeneratedBy relation.
>> 
>> from http://www.w3.org/TR/prov-dm/#prov-dm-overview
>> 
>> "Qualifiers can be associated to relations, namely use and wasGeneratedBy,
>> in order to further characterize their nature. Role is a pre-defined
>> qualifier."
>> 
>> and from http://www.w3.org/TR/prov-dm/#expression-qualifier
>> 
>> "The PROV data model introduces the qualifier role in the PROV-DM namespace
>> to denote the function of a characterized thing with respect to an activity,
>> in the context of a use/generation/control relation. The value associated
>> with a role attribute must be conformant with Literal."
>> 
>> I have sensed confusion in the prov-o discussions as to whether the role in
>> a generation is played by the process execution or the generated entity.
>> 
>> 
>> 
>> I don't think many people have misinterpreted the prov:hadRole's value to be
>> the role of an Activity; it is the role of the Entity, as you cite from the
>> DM above.
>> 
>> 
>>  Can a generated entity play a role in the activity that generates it?
>> 
>> 
>> Absolutely
>> 
>>  Can a process execution play a role, that is be the characterized thing
>> that has a function in an activity?
>> 
>> 
>> 
>> The Activity is self-roling. It's existence establishes its characterization
>> and can be modeled explicitly by specializing Activity.
>> 
>> 
>>  Does the definition of role need to be changed?
>> 
>> 
>> I don't think so.
>> 
>> 
>> I know discussion of role has taken up a lot of time, this sure has turned
>> out to be a tricky issue, but I think getting qualifiers right is worth it.
>> 
>> There is an example in the primer,
>> http://dvcs.w3.org/hg/prov/raw-file/default/primer/Primer.html#roles-1,
>> 
>> 
>> 
>> 1) The name  ex1:aggregated seems a bit odd, since it sounds like it is the
>> output and not the activity itself.
>> 
>> 2) I'd suggest adding types for Activities in the examples.
>> 
>> but I am not sure if it is representative of the intent for role on a
>> generation relation.
>> 
>> ex1:aggregated
>>   prov:hadQualifiedGeneration [ a prov:Generation ;
>>       prov:hadQualifiedEntity ex1:aggregate1 ;
>>       prov:hadRole ex1:aggregatedData
>>   ] .
>> 
>> 
>> 
>> Perhaps the example
>> from http://www.w3.org/2011/prov/wiki/Qualifed_Involvements_in_PROV-O#Qualified_Generation_with_Roles
>> would make roles of generated entities more clear:
>> 
>> :pe
>>    a prov:ProcessExecution;
>> 
>>    prov:generated :output;
>>    prov:hadQualifiedGeneration [
>>       a prov:Generation;
>>       prov:hadQualifiedEntity         :output;
>>       prov:hadRole            workflow:output;
>>    ];
>> 
>>    prov:generated :metadata;
>>    prov:hadQualifiedGeneration [
>>       a prov:Generation;
>>       prov:hadQualifiedEntity         :metadata;
>>       prov:hadRole            workflow:metadata-of-output-with-log;
>>    ];
>> .
>> 
>> 
>> 
>> 
>> -Tim
>> 
>> 
>> 
>> 
>> 
>> --Stephan
>> 
>> 
>> 
>> 
>> 
>> 
>> --
>> 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
> 
> 
> 
> -- 
> Dr Simon Miles
> Lecturer, Department of Informatics
> Kings College London, WC2R 2LS, UK
> +44 (0)20 7848 1166
> 
> Provenance: The Bridge Between Experiments and Data:
> http://eprints.dcs.kcl.ac.uk/1372/
> 
> 
Received on Wednesday, 21 December 2011 18:13:29 GMT

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