- From: Dave Reynolds <dave.e.reynolds@gmail.com>
- Date: Thu, 29 Nov 2012 15:17:22 +0000
- To: Jun Zhao <jun.zhao@zoo.ox.ac.uk>
- CC: public-gld-comments@w3.org, Provenance Working Group WG <public-prov-wg@w3.org>
Jun, Thank you very much for your detailed review comments on ORG and particularly ORG's use of PROV-O. The working group will examine these comments and respond formally later once we have determine how to address them. Best wishes, Dave On 25/11/12 09:43, Jun Zhao wrote: > Dear Organization Ontology Editors, > > The PROV WG reviewed the part of the document about extension to PROV. > Generally speaking we agree with your following extensions: > > - org:originalOrganization as a subproperty of prov:used, > - org:resultedFrom as a subproperty of prov:wasGeneratedBy > - org:ChangeEvent as a subclass of prov:Activity > > In addition, we would like to draw your attention to the concept of > derivation [1] in PROV, which refers to a transformation of an entity > into another, an update of an entity resulting in a new one, or the > construction of a new entity based on a pre-existing entity. Based on > some general knowledge, one might expect that a new organization should > be a derivation of the old one, by some sort of transformation or update > or simply setting up a new entity. But does this indeed make sense with > the use cases that you consider? > > This is a strong albeit useful assertion, enabling you to trace the > history of an organization. However, the semantics of the PROV model > does not let you infer this relationship by the combination of > generation and usage, i.e., from the following triples: > > ex:o2 org:resultedFrom ex:a1 > ex:a1 org:originalOrganization ex:o1 > > The PROV model regards ex:o1 and ex:o2 as totally unrelated, unless > their relationship is explicitly stated otherwise. If the definition of > derivation does fit your use case, making use of this relationship in > your ontology will make it much more in line with the upcoming > provenance recommendation. So it is a matter to have a think about what > you intend to achieve by using the prov:used and prov:wasGeneratedBy > properties. If you want to include derivation in your ontology, then we > make the following to suggestions: > > 1. We RECOMMEND that ex:o2 prov:wasDerivedFrom ex:o1 be explicitly > asserted. (or a subproperty in the org: namespace) > 2. Alternatively, you could add a property chain > org:resultedFrom followed by org:originalOrganization => > prov:WasDerivedFrom > > > The second point is that the PROV model comes with a set of implicit > semantics constraints (in its constraint document [2]). Although these > constraints are not reflected in the PROV-O, we expect that a provenance > validator, compliant with this document, will validate provenance > statements on the Web. Therefore, it might be worthwhile to take a pause > and think whether the intention behind your ontology might lead to any > violation to relevant constraints. > > For example, the generation-precedes-usage constraint [3] requires that > the event when a new organization was generated must precede the event > when the same organization was used in the process of generating another > organization. > > > Finally, we would also like to bring your attention to the concept of > invalidation. In the PROV data model we say that an entity can have a > lifetime. And the invalidation is the start of the destruction, > cessation, or expiry of an existing entity by an activity [4]. > > If this concept is adopted in the Organization Ontology, then you will > be able to specify more precisely that the cease-to-exist of the old > organization when a new organization was built up. Might this be helpful > to your use cases? > > Please be aware that by using this concept, there are several related > constraints to bear in mind. An example is the > usage-precedes-invalidation constraint [5], which means that the event > when an old organization ceased to exist must follow the event when it > was used in the org:ChangeEvent activity. > > We, the WG as a whole, will be happy to help you with any other issue > related to PROV. > > Hope this helps. > > Jun, on behalf of the PROV WG > > [1] http://www.w3.org/TR/prov-dm/#term-Derivation > [2] http://www.w3.org/TR/2012/WD-prov-constraints-20120911/ > [3] > http://www.w3.org/TR/2012/WD-prov-constraints-20120911/#generation-precedes-usage > > [4] http://www.w3.org/TR/prov-dm/#term-Invalidation > [5] > http://www.w3.org/TR/2012/WD-prov-constraints-20120911/#usage-precedes-invalidation > >
Received on Thursday, 29 November 2012 15:17:59 UTC