On Aug 11, 2009, at 5:51 AM, ingvar_johansson wrote: (01)
> John Sowa wrote,
>
>> It is true that the latest and greatest science and technology was
>> necessary to define the units of measure to the current degree of
>> precision. However, we must remember that the same words were
>> used for those units in the 19th century. The values used then
>> differ from the current values by much less than 1%.
>
>> The UoM ontology should be little more than a compendium of the
>> values of the units and the relations among them. The details
>> of how they were derived is not necessary for using them.
>
> Not contesting what John here says, I would like to add that I think
> that
> it is good for UoM ontology constructors to be aware of the
> following four
> facts:
>
> 1. Ratio scales, interval scales, and ordinal scales require different
> formalisms. (02)
Surely not. We plan to produce an ontology all written in one formalism. (03)
Let me test my understanding of these terms.
A scale is a set of items used to represent measurements.
An ordinal scale is a scale with a total order on its elements.
An interval scale is a scale with a difference function from pairs of
scale items to ... (what? Real numbers? Some other scale? Could there
be an interval scale in which differences were restricted to natural
numbers, for example?).
A ratio scale is a scale which has a zero element and a multiplication
operation by rational numbers. (04)
(My source for this is
http://www.stat.sfu.ca/~cschwarz/Stat-301/Handouts/node5.html
, by the way, found through google) (05)
>
> 2. Out of every ratio scale an interval scale can be constructed,
> and out
> of every interval scale an ordinal scale can be constructed, but not
> conversely.
>
> 3. In the late nineteenth century, physics was able to replace the
> existing interval scales for temperature with a ratio scale for
> temperature (the Kelvin scale).
>
> 4. There is no axiom or theorem to the effect that science can turn
> all
> ordinal scales into interval scales, and all interval scales into
> ratio
> scales. (06)
Right, all those make perfect sense. (07)
Pat (08)
>
> Ingvar J
>
>
> _________________________________________________________________
> Message Archives: http://ontolog.cim3.net/forum/uom-ontology-std/
> Subscribe: mailto:uom-ontology-std-join@xxxxxxxxxxxxxxxx
> Config/Unsubscribe: http://ontolog.cim3.net/mailman/listinfo/uom-ontology-std/
> Shared Files: http://ontolog.cim3.net/file/work/UoM/
> Wiki: http://ontolog.cim3.net/cgi-bin/wiki.pl?UoM_Ontology_Standard
>
> (09)
------------------------------------------------------------
IHMC (850)434 8903 or (650)494 3973
40 South Alcaniz St. (850)202 4416 office
Pensacola (850)202 4440 fax
FL 32502 (850)291 0667 mobile
phayesAT-SIGNihmc.us http://www.ihmc.us/users/phayes (010)
_________________________________________________________________
Message Archives: http://ontolog.cim3.net/forum/uom-ontology-std/
Subscribe: mailto:uom-ontology-std-join@xxxxxxxxxxxxxxxx
Config/Unsubscribe: http://ontolog.cim3.net/mailman/listinfo/uom-ontology-std/
Shared Files: http://ontolog.cim3.net/file/work/UoM/
Wiki: http://ontolog.cim3.net/cgi-bin/wiki.pl?UoM_Ontology_Standard (011)
|