Based on my experiences, I fully agree that intervals often come from measurements for which we only know the upper bound D on the measurement inaccuracy, and thus, after receiving the measured value X, the only information that we have about the actual (unknown) value x of the measured quantity is that this quantity belongs to the interval [X-D,X+D].
I do not think anyone disagrees with this. Arnold's main point is that while this is a good point for representing initial intervals, in many cases, the best way to process these intervals is to transform them into what people on the list call min-max representation. At the end, it may be a good idea to represent the resulting interval [y,Y] not by its bounds, but in the form y0 + d+ - d- (e.g., 1.0 + 0.1 - 0.05) meaning that the deviations from the nominal values are within the interval [-d-,d+].
-----Original Message-----
From: stds-1788@xxxxxxxx [mailto:stds-1788@xxxxxxxx] On Behalf Of Nate Hayes
Sent: Tuesday, May 11, 2010 8:27 AM
To: John Pryce; P1788
Subject: Re: mid-rad, inf-sup, a caution...
John Pryce wrote:
A.
I note that Baker originally wrote
... warrant standardizing separate *interchange* formats ...
That may be relatively easy - easier than making mid-rad a
first-class companion to inf-sup. I should appreciate mid-rad experts
clarifying some points about the specification that would be needed
if it's ONLY interchange format we talk about:
- Who will benefit? Who wants to exchange interval data between
systems, based on mid-rad formats?
Has anyone in this forum ever worked with a mechanical engineer or
architect, or seen the computer software tools they use? In those
applications and domains, tolerancing of parts is almost always done in
mid-rad, e.g.,
http://www.youtube.com/watch?v=H7f5cjspuAs&feature=related
we should be so lucky that some of the largest and most successful software
companies in the world, such as Autodesk, Dassault Systems, Parametric
Technology, etc. would some day use our P1788 standard. Having at least an
interchange format for mid-rad with standardized conversion rules I suspect
would be a minimal requirement.
I would also point out that at least in this sense, mid-rad as an
"interchange format" is already a global, multi-billion dollar industry.
Something that can't be said for inf-sup.