OWL ontology for unit

[Sebastien Derriere]

Ed Shaya wrote:
> 
>     As an example, I used the Protege Ontology Builder (
> http://protege.stanford.edu/ ) and the OWL pluggin (
> http://protege.stanford.edu/plugins/owl/ ) to create an ontology for
> describing the various physical units in such a way that they can be
> decomposed to baseUnits in SI (gram, meter, second, kelvin, etc).

  Hello,

  This reminds me of the work by Gruber and Olsen, about the EngMath
ontology. You can find their 1994 paper here:
http://www-ksl.stanford.edu/knowledge-sharing/papers/engmath.html
  They give a rather complete and coherent description of mathematical
expressions in an ontology context. But it is based on LISP, not OWL.

  They give descriptions of UNIT-OF-MEASURE
http://www-ksl.stanford.edu/knowledge-sharing/ontologies/html/physical-quantities/UNIT-OF-MEASURE.html

  and also of STANDARD-UNITS
http://www-ksl.stanford.edu/knowledge-sharing/ontologies/html/standard-units/index.html

>     This all should prove really useful if we get to the stage where we
> want to automatically merge columns of
> data or quantity objects and we need an automated way to check if the
> two streams of data have the same
> physical units and then, if they are, determine what is the constant
> factor between them.

  I think that ontologies can prove very useful to describe some
semantic links between concepts. However, I think that they are
not the proper way to describe mathematical relationships. I have
not been able to find any single application of an ontology to
interpreting mathematical relations, except the theoretical paper
from Gruber and Olsen, 1994. 
  I think that ontologies are not meant for this.

  You have very simple ways of parsing units without ontologies:
in recent linux distributions, just look at the 'units' command.

  By the way, the base SI unit is kg, not gram.

Cheers,

Sebastien.


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