Hi Gerard,
they actually could be, but whenever this discussion comes up, no-one
proposes it. I'm not sure if I would either, because these arbitrary
units are still not computable in general, but 'dose units' can be made
computable but only with some extra data fields, i.e. you need both the
quantity of dose in 1 tablet/capsule etc, and also number of
tablet/capsule etc. So the structural model is different anyway.
I think the other problem with using UCUM arbitrary units is that people
/ orgs want to control the names of medicinal delivery products
('tablet' etc) in a terminology, which is reasonable, but doesn't fit so
well with UCUM.
- thomas
On 19/05/2016 08:11, "Gerard Freriks (privé)" wrote:
Thomas,
All are Units of a different kind.
SI defines: Units of Measure, and Units of Quantity in the scientific
domain.
There are also Units of Time: minute, hour, etc.
When I think of tablets, capsule, etc. we will call these Units of
Medicinal Product Dose.
Isn’t in UCUM this an example of Arbitrary Units?
3.2
ARBITRARY UNITS
*§24 arbitrary units* *^ ■1 * Arbitrary or procedure defined units are
units whose meaning entirely depends on the measurement procedure
(assay). These units have no general meaning in relation with any
other unit in the SI. Therefore those arbitrary semantic entities are
called /arbitrary units/, as opposed to /proper units/. The set of
arbitrary units is denoted /A/, where /A/∩ /U/ = {}. *^ ■2 * An
arbitrary unit has no further definition in the semantic framework of
/The Unified Code for Units of Measure/ *^ ■3 * Arbitrary units are
not “of any specific dimension” and are not “commensurable with” any
other unit.
Until version 1.6 /The Unified Code for Units of Measure/ has dealt
with arbitrary units as dimensionless, but as an effect the semantics
of /The Unified Code for Units of Measure/ made all arbitrary units
commensurable. Since version 1.7 of /The Unified Code for Units of
Measure/ it is no longer possible to convert or compare arbitrary
units with any other arbitrary unit.
*§25 operations on arbitrary units* *^ ■1 * Any term involving
arbitrary units, is itself an arbitrary unit and is not comparable
with any other arbitrary unit or term.
*§26 definition of arbitrary units* *^ ■1 * Arbitrary units are marked
in the definition tables for unit atoms by a bullet (‘•’) in the
column titled “value” and a bullet in the column titled “definition”.
Gerard Freriks
+31 620347088
[email protected] <mailto:[email protected]>
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