- From: Luc Moreau <L.Moreau@ecs.soton.ac.uk>
- Date: Wed, 27 Jul 2011 15:39:33 +0100
- To: public-prov-wg@w3.org
Hi, The latest version of the document contains a proposal [1] to address this issue. The text is copied here for convenience: Use, Generation, and Control assertions must contain a role. Roles are mandatory since they allow for uniform data structures. To facilitate the writing of these assertions when a role is unknown by the asserter, syntactic notations may allow these to be written without a role. In such a case, a default, uniquely named role from the set 'unspecified role' will be assumed. A countable set of unique labels can be used to denote unspecified roles, as in: unspecified0, unspecified1, unspecified2, .... What do you think? Paolo and Luc [1] http://dvcs.w3.org/hg/prov/raw-file/default/model/ProvenanceModel.html#concept-Role On 07/25/2011 11:05 AM, Luc Moreau wrote: > > > On 07/25/2011 10:52 AM, Paul Groth wrote: >> Ok... and the justification for this is that it makes the data >> structure uniform....? > Yes >> >> It seems that this unspecified role will have some kind of special >> semantics, no? >> > It's a default role for asserters who don't assert a specific role. > > Luc > >> Paul >> >> Luc Moreau wrote: >>> Remember that I suggested concrete representations have the >>> opportunity to >>> offer role-less convenience syntax (as a kind of "macro" that expands >>> into a construct >>> with a role "unspecified"). >>> >>> Using the notation in the spec: >>> use(pe,e) expands to use(pe,e,unspecifiedRole) >>> where unspecifiedRole is a distinguished role. >>> >>> Isn't your requirement about "easy writing"? I believe an appropriate >>> choice of syntax addresses this requirement. >>> >>> Luc >>> >>> >>> On 07/25/2011 10:35 AM, Paul Groth wrote: >>>> I'm using the definitions in [1], which are used in W3C specs. The >>>> definitions for MUST and SHOULD are: >>>> >>>> - MUST This word, or the terms "REQUIRED" or "SHALL", mean that the >>>> definition is an absolute requirement of the specification. >>>> >>>> - SHOULD This word, or the adjective "RECOMMENDED", mean that there >>>> may exist valid reasons in particular circumstances to ignore a >>>> particular item, but the full implications must be understood and >>>> carefully weighed before choosing a different course. >>>> >>>> >>>> The justification for using SHOULD is that it allows me some >>>> flexibility in writing down provenance that is compatible with the >>>> spec. If I don't know the roles and I won't break anything but I might >>>> not get the full functionality of the spec (maybe?). So I think that >>>> there are valid reasons not to write down roles but probably I should >>>> think before not doing it. >>>> >>>> cheers, >>>> Paul >>>> >>>> >>>> [1] http://www.ietf.org/rfc/rfc2119.txt >>>> >>>> Luc Moreau wrote: >>>>> It would be good to have advise on the choice MUST/SHOULD. >>>>> >>>>> I would have thought that to promote interoperability we should go >>>>> for >>>>> the stronger requirements, >>>>> when possible. >>>>> >>>>> I can turn your comment around. I'm missing a justification for a >>>>> SHOULD >>>>> here. >>>>> >>>>> Luc >>>>> >>>>> >>>>> PS. I don't think it's a hack to have unspecified role. Mandating >>>>> a role >>>>> guarantees a uniform data structure. >>>>> It facilitates the writing of queries/searches. I guess >>>>> that's my >>>>> justification for MUST. >>>>> >>>>> >>>>> On 07/25/2011 10:22 AM, Paul Groth wrote: >>>>>> It seems like unspecified is a hack to let you get around not >>>>>> saying a >>>>>> role. >>>>>> >>>>>> Again, I think I'm missing a justification of the MUST verses just >>>>>> making it a strong recommendation (i.e. SHOULD). >>>>>> >>>>>> I think you have some inferences in mind based around roles.... >>>>>> but I >>>>>> think it just means that you won't be able to make those >>>>>> inferences if >>>>>> you don't provide roles. >>>>>> >>>>>> thanks, >>>>>> Paul >>>>>> >>>>>> Luc Moreau wrote: >>>>>>> I believe there is a difference between a conceptual model and its >>>>>>> encoding in >>>>>>> a specific data/knowledge format. >>>>>>> >>>>>>> In my view, it is reasonable to require the presence of a role in a >>>>>>> conceptual model. >>>>>>> A given notation, say RDF, may provide "abbreviations", which allow >>>>>>> for >>>>>>> the role not >>>>>>> to be expressed. This notation will have an explanation that >>>>>>> absence of >>>>>>> a role corresponds >>>>>>> to the role "unspecified". >>>>>>> >>>>>>> So, I believe that the conceptual model should define distinguished >>>>>>> roles, e.g. unspecified. >>>>>>> >>>>>>> BTW, the file note.txt in the repository also suggested other roles >>>>>>> >>>>>>> Luc >>>>>>> >>>>>>> >>>>>>> >>>>>>> On 07/23/2011 03:14 PM, Provenance Working Group Issue Tracker >>>>>>> wrote: >>>>>>>> PROV-ISSUE-40 (recommended-roles): Roles should not be SHOULD and >>>>>>>> not MUST [Conceptual Model] >>>>>>>> >>>>>>>> http://www.w3.org/2011/prov/track/issues/40 >>>>>>>> >>>>>>>> Raised by: Paul Groth >>>>>>>> On product: Conceptual Model >>>>>>>> >>>>>>>> Currently, roles are required for Generation, Use, and >>>>>>>> isControlledby. >>>>>>>> >>>>>>>> Specifically the following sentence is given: >>>>>>>> >>>>>>>> "Use, Generation, and Control assertions must contain a role." >>>>>>>> >>>>>>>> It is not clear why roles must always be there. In some cases, >>>>>>>> I may >>>>>>>> not want to assert the role that something played with respect >>>>>>>> to a >>>>>>>> process. >>>>>>>> >>>>>>>> Suggested resolution is to replace MUST with SHOULD. >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>> >> > -- 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
Received on Wednesday, 27 July 2011 14:40:04 UTC