Re: XG W3pm Scope

David Leal wrote:
> Dear All,
>
> Michel's three top items seem to be a good starting point. (Another minor
> procedural point - I would like to suggest using N3 rather than XML for RDF
> examples wherever possible.)
>
>   
I'm not particularly fond of N3 personally.  It is compact and easier to 
write, but
I find it harder to read.
> I have some initial thoughts on quantities and units, as follows:
Can we try to make the email subject match the topic covered?  If we are 
going to talk about
a units model let's say that in the subject line.

With respect to your suggested units model:
Generally, I agree with a units model based on Systems Of Quantities 
(such as the ISQ defined
in ISO 80000) which define Quantity Dimensions (which is what *I* might 
have called a
PhysicalQuantitySpace) used in a corresponding System Of Units (such as 
SI).  I don't agree
with the terms that you use or the way that you are modeling them.  Here 
I am using
terminology from VIM (International Vocabulary of Metrology).  There are 
also some
short-comings to this kind of system though.  It loses information for 
ratios, doesn't distinguish
discrete amounts (counts or "number of entities"), and the dimensions 
for derived
units/quantityTypes (aka Kinds of Quantity) don't uniquely identify the 
type of the quantity being
described.  Any OWL model for units and quantities should provide some 
means to provide or
derive this information.

The following triple raises a more fundamental question:

> :PhysicalQuantitySpace    rdfs:subClassOf owl:Class .

How is the Product Modeling XG planning on using the Semantic Web 
languages?  The above
triple messes with the OWL vocabulary.  Do you care if you stay in OWL 
DL or do you intend
your OWL/RDFS model for these things to be merely a schema for data in 
RDF form?

-Evan

Evan K. Wallace
Manufacturing Systems Integration Division
NIST

Received on Friday, 30 May 2008 14:30:29 UTC