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

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