(j3.2006) (SC22WG5.5829) WG5: Harmonizing terminology in N2113 with ISO 80000-1

David Muxworthy d.muxworthy
Thu Dec 22 13:19:33 EST 2016

The following message from a non-member was rejected by the WG5 mail server and has only just come to my attention.  It is forwarded in case it is of interest.  The table, originally in html, has been reformatted into plain text.  I trust it is legible.

From: Marcus Foster <marcus.foster at outlook.com>
To: "sc22wg5 at open-std.org" <sc22wg5 at open-std.org>
Subject: WG5: Harmonizing terminology in N2113 with ISO 80000-1
Date: Tue, 6 Dec 2016 02:19:30 +0000

Dear members of WG5
I congratulate you on articulating the importance of unit-of-measure checking in scientific programs and preparing a draft TS (N2113). To quote an Australian political slogan of 1972, "It's time".

Permit me to comment on the terminology used in that draft TS, as it is inconsistent with ISO 80000-1 Quantities and units - general, the ISO standard which underpins scientific measurement.

A brief history: the language of science (quantities, units, dimensions etc) has been used differently by different disciplines. Following Dimensional Analysis (Bridgeman, 1922), engineers described the cgs and MKS as three-dimensional systems of units. The first edition of the SI Brochure (BIPM, 1970) lists quantities and units, but not dimensions and so on. In my experience, the computer-science literature tends to use these terms loosely and consequently can blur these concepts.

The Joint Committee on Metrology (JCGM) set 'quantity' as the primary concept in systems of units, and published the International Vocabulary of Measurement (VIM) in 1978, and VIM3 in 2012. ISO 80000-1 is based on VIM3. It defines and gives synonyms and commentary for terms related to measurement. The terms of interest here are 'quantity' (no synonyms), 'base quantity', 'quantity dimension' ('dimension of a quantity', 'dimension'), and 'unit of measurement' ('measurement unit', 'unit').

Here are some changes that can be made to N2113 to harmonize it with ISO notation and scientific practice. In particular, the terms on the first two columns of the table in Shortcomings 1 are reversed; and the term 'fundamental' is not used as a qualifier in the BIPM SI brochures nor ISO 80000

Location		N2113 term			ISO 80000 term

Title and elsewhere	numerical quantities		quantities

P.v, shortcomings 1,	exponents of fundamental	exponents of base
line 4			dimensions			quantities

P.v, shortcomings 1,	exponents for the fundamental	exponents for the SI
line 7			SI units or dimensions		base units or dimensions

P.v, shortcomings 1,	Fundamental SI unit		SI base quantity	

P.v shortcomings 1,	Fundamental SI dimension	SI base unit

P.vi, shortcomings 2,	ISO fundamental units		SI base quantities
line 1

P.vi, shortcomings 2,	non-physical dimensions		Non-physical quantities
line 6

P.vi, shortcomings 2,	Dimensions that are not		quantities that are not 
line 6			described using exponents of	described using exponents 
			fundamental dimensions		of base quantities

P.vi, shortcomings 4,	distinguish units		distinguish quantities
line 1			(e.g., length from time)	(e.g., length from time
			but not dimensions or measures	but not units (e.g., pounds
			(e.g., pounds from kilograms).	from kilograms).

P.vi, shortcomings 5,	different type for each		different type for each
line 1			measure				unit

P.1 line 6		Fundamental SI units		SI base quantities

P.1 line 11		fundamental SI dimensions	Si base units

P.9, 5.1 third dot	distinguish different measures	distinguish different
point			of the same fundamental		units of the same
			quantity,			quantity,

Marcus Foster
Torquay, Australia

https://scholar.google.com.au/citations?hl=en&user=jPZcPiwAAAAJ&view_op=list_works&sortby=pubdate" id="LPlnk451350" previewremoved="true"


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