Hi Tom It's a strange concept for sure. The real question here is whether UCUM and PQ/DV_QUANTITY are for real measurements, or whether they for quantitative notions.
There's general agreement that things like "tablet" etc are not UCUM units - because they're not quantitative. Now we have a different issue - these are quantitative, but not real. I can see the grounds for keeping them out of UCUM. In addition, I'd have to recode my ucum library for this, and it's an odd challenge for such a strange notion. On the other hand, why not let scientists how measure things measure them how they want, as long as the units are meaningful - to them. Grahame On Fri, Apr 29, 2011 at 7:14 PM, Thomas Beale <thomas.beale at oceaninformatics.com> wrote: > > it is a pretty weird unit, since it is partway between 2-d and 3-d space, > and therefore partway between the concept of 'area' and that of 'volume'. So > whether it is acceptable depends on whether we think that such concepts are > meaningful in the activity we call 'measurement' in the physical world. > Probably there are weird units like this in quantum mechanics, or other > esoteric mathematical spaces, so then it comes down to scope of UCUM - > presumably not all of science, just physical measurement? > > Changing openEHR or HL7 to handle it probably would not be hard, but it > might open up a can of worms, and also just plain annoyances, by allowing > fractional dimensions (i.e. as soon as you start using floating point > numbers for values that are almost always integers, computers struggle to > get it right...). > > - thomas > > On 29/04/2011 01:48, Grahame Grieve wrote: > > Hi Leo > > Gunther says that these units are not proper units. > > http://www.xkaw.com/Education_Reference/Science_Mathematics.asp?id=2276318 > > There's a possible question of scope alignment here. It's kind of tantamount > to > saying that a measure like that is not a proper measurement. I don't think > I agree with that. > > To pursue the UCUM issue, you need to make at ticket at > http://www.unitsofmeasure.org/ > > I think that there's a tension here between the notion of purity from UCUMs > point of view, and the use of UCUM in the measurement data types (PQ in > HL7 v3 and DV_QUANTITY in openEHR - both have the same scope and the > same usage of UCUM) > > Also see http://www.unitsofmeasure.org/wiki/ProcedureDefinedUnits > > Grahame > > > > > _______________________________________________ > openEHR-technical mailing list > openEHR-technical at openehr.org > http://lists.chime.ucl.ac.uk/mailman/listinfo/openehr-technical > > -- ----- http://www.healthintersections.com.au / grahame at healthintersections.com.au / +61 411 867 065
