Dear Matthew and William, (01)
Before saying anything further about the details, I want to emphasize
that Mathew West's HQDM ontology is actually quite good of its kind.
He worked at Shell in using the EXPRESS notations to develop an upper
level ontology that was successfully used in wide range of applications.
For a brief summary of EXPRESS, see (02)
http://en.wikipedia.org/wiki/EXPRESS_(data_modeling_language) (03)
EXPRESS is a text notation. The graphic subset (EXPRESS-G) represents
type-subtype and Entity-Relationship diagrams. To support full FOL,
the text form adds a WHERE-clause that can state arbitrary constraints. (04)
In principle, this is a very good combination. The WHERE-clause in
EXPRESS is far more readable than the UML Object Constraint Language.
For ontology, this combination of diagrams + text is more flexible
and readable than OWL 2. I recommend it for OWL 3. (05)
I apologize for extracting an excerpt from a note by Matthew and
posting it in a comment to this forum without giving enough context.
But William's reactions illustrate the point that a better choice
of terminology would be desirable. (06)
WF
> these examples seem to be so contrived and unnatural that I wonder
> about the enterprise they are related to. (07)
Following is another excerpt from a note by Matthew: (08)
MW
> I am more than 4 years out of Shell now, and the Downstream Data Model
> was certainly Shell Confidential. However, my book "Developing High Quality
> Data Models" http://store.elsevier.com/product.jsp?isbn=9780123751065
> provides a further development of some parts of that work. The data model
> (but not the explanation) from that is also available on the web at:
> http://homepages.rya-online.net/matthew-west/hqdm_framework/ (09)
Click on the last link and then click on HQDM Framework. That will show
229 links for entity types. Click on any of them for more detail, which
is stated in the EXPRESS text notation. (010)
HQDM
> kind_of_activity
> A class_of_activity all of whose members are of the same kind. (011)
JFS
> Much simpler:
> kind_of_activity: a one-place relation that is true of every activity
> of the same kind. (012)
WF
> I agree with JS, vis-a-vis predicates vs. 'classes'
> But what seems to me to be most fundamentally wrong in this discussion
> is the notion that there is a good reason to define 'kind of activity'
> separately from 'kind of stone' or kind of hope'. (013)
Yes. The word 'class' is useless baggage that creates more confusion
than it's worth. (014)
MW
> I might not choose class if I had my time again, but in ISO 15926 that
> is history now, and changing it would be more confusing than leaving
> it the same. (015)
Unfortunately, the people who defined ISO 15926 made a poor choice.
But the EXPRESS notation does not require the word 'class'. Avoiding
that word should not violate ISO 15926. (016)
MW
> The principle purpose of an upper ontology is that you relate the
> terms of domain experts and SMEs to that upper ontology together,
> thereby bringing together similar concepts, and distinguishing
> different uses of the same terms. You can then also apply templates
> from the upper ontology to the domain terms and improve the
> consistency of the ontology at the domain level. (017)
I agree that the mid-level terms used by the Shell engineers must be
supported by the upper ontology. That requirement is non-negotiable. (018)
But the Shell engineers don't use the word 'class'. I don't know how
ISO 15926, the EXPRESS and EXPRESS-G notations, and the terminology
of the Shell engineers are interrelated. But I suspect that there
should be some way to simplify the definitions to eliminate that word. (019)
John (020)
PS: Happy New Year. (021)
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