Re: quantities as units

Hi Brian,

You might look at the SysML specification [1] for additional guidance.  
There is an annex in the document called Quantities, Units, Dimensions, 
and Values (QUDV), that may have motivated the TQ work, at least in 
part.  The document may have more suggestions with respect to derived 
units than I've seen in the online documentation for the ontology.

There is also work going on at OMG in parallel to develop a standard 
ontology for the QUDV part of SysML, which JPL has been spearheading, 
but I am not aware of anything publicly available at this point.   This 
effort will include a number of examples on how to create/use derived 
units, but I don't know when you should expect to see anything come out 
of the process.

Yet another parallel OMG effort, focused on dates and times in 
particular, will be published as a result of the OMG technical meeting 
coming up next week.  The first iteration will be an SBVR vocabulary, 
with equivalent statements in Common Logic and OCL, but several of us 
have been working on an OWL subset which will be published as an annex 
to the specification over the coming months, and freely available from 
the OMG site.  The dates and times vocabulary diverges slightly from the 
QUDV specification at present (we're still working to determine whether 
or not some subtle differences can be resolved), but only addresses 
units, including derived units, required for representation of time.  
Many standards were used as input to this, including de facto ontologies 
such as OWL Time, and it's a thoughtful, pragmatic, and comprehensive 
piece of work.

Best regards,

Elisa

[1] http://www.omg.org/spec/SysML/1.2/ -- see Annex C: Non-normative 
Extensions, section C.5.


On 3/15/2011 7:56 AM, Brian McBride wrote:
> I'm looking to represent some data in which I have units that are, 
> loosely speaking, quantities of something, e.g. equivalent to Kg of 
> CO2 as a unit for global warming potential.  The environmental 
> community measure a  number of things in terms of units like this.   
> I'm thinking of using qudt [1] as the quantities/units ontology.
>
> I could just define a new Kind (GWP) and a new unit (Kg of CO2 equiv) 
> (or maybe someone else has done that already).  It seems like it would 
> be better to express this unit in terms of the already defined unit 
> Kg.   I can't see how to do this with qudt.
>
> I was wondering if anyone had done something like this before.
>
> Brian
>
>
> [1] http://www.qudt.org/
>
>

Received on Tuesday, 15 March 2011 16:17:13 UTC