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Re: Feedback to the LC of the Organization Ontology from the Prov WG

From: Dave Reynolds <dave.e.reynolds@gmail.com>
Date: Thu, 21 Feb 2013 16:17:26 +0000
Message-ID: <51264896.1020805@gmail.com>
To: Jun Zhao <jun.zhao@zoo.ox.ac.uk>
CC: public-gld-comments@w3.org, Provenance Working Group WG <public-prov-wg@w3.org>
Dear Jun and Provenance Working group,

Thank you again for your helpful and thoughtful comments on the 
Organization Ontology and its use of PROV-O terms.

You offered three comments:
  1. that prov:wasDerivedFrom should be explicitly or implicitly
     asserted
  2. that we should check that our intended use of PROV-O would not
     lead to any violation of the PROV semantic constraints [1]
  3. that we might consider use of PROV invalidation terms

1. prov:wasDerivedFrom

We agree with your recommendation that a prov:wasDerivedFrom
relationship should exist between the org:originalOrganization and
org:resultedFrom Organization of an org:changeEvent. We have adopted
your suggestion of expressing this by means of a property chain axiom
and have added this axiom to the ontology and added an explanatory
example as part of informative section [2].

2. Semantic Constraints

We have examined the semantic constraints expressed in [1]. We see no
conflict between those and intended usage of ORG. For those terms in
ORG which relate to PROV-O terms we see no semantic constraints which
would limit usage of the ORG terms themselves. Applications of ORG
which make direct use of additional PROV-O terms (e.g. to describe the
time period of a change event) should naturally take the semantic
constraints on those terms into account. We have included a mention of
this in the informative section [2].

3. PROV invalidation terms

Thank you for bringing this part of PROV to our attention. There may
well be applications of ORG which also wish to express such
invalidation information in which case they should be, and are, free
to use the relevant PROV-O terms. However, we do not have particular
use cases in this area and feel the existing references to PROV-O are
sufficient to allow ORG users to decide whether additional parts of
PROV-O, like this, are relevant to their usage.

We would be grateful if you could confirm if you are content with
these responses.

Thanks again for your feedback, much appreciated.

Dave Reynolds (on behalf of GLD working group)

[1] http://www.w3.org/TR/2012/WD-prov-constraints-20120911/
[2]
https://dvcs.w3.org/hg/gld/raw-file/default/org/index.html#organizational_history 


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, 21 February 2013 16:17:56 GMT

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