Matthew,
(01)
I wrote:
(02)
> Humans often exchange these curves as graphs, but software isn’t good at
>turning PNG images into quantitative performance estimations.
> I know for a fact that this last problem is not solved in 15926,
(03)
Matthew wrote:
(04)
> MW: There is something called multidimensional_property_space which was
>intended to handle things like pump curves. Were you aware of that, or have
>you tried it and found it wanting? I’d be interested in your experience. The
>idea would be to specify sufficient points from the curve that you were happy
>to interpolate between them.
(05)
I understand this thing to be a sequence of points in n-space, where each
dimension is a property. The ontological problem is that that is not a curve
-- it is a sequence of points. In the STEP models, for example, there are
B-spline curves that are defined by a series of inflection points, and that
series defines a unique curve. The series is defined to be the representation
of a B-spline, with that interpretation of the points. If I specify a set of
points and require a particular fit algorithm for a particular kind of
parametrized function, that is the definition of a curve. I suppose there
should be specializations of the general multidimensional_property that would
clarify this, but the idea that it is a sequence of points in n-space doesn’t
mean much by itself. (I would say this is an ontology of a representation and
not of the concept.)
(06)
That said, the sad fact is that a pump curve really is just someone's fit to a
set of actually measured values for particular inputs, and the real data is
just the pairs (input, measured behavior). The fit is indeed in the eye of the
sender, and if the receiver uses a different algorithm and gets a different
curve, neither of them is necessarily "right" (they are just the products of
different engineering intuitions or skills), and the proof of the pudding will
come in the pump test. That is, the multidimensional_property really is just a
set of observations. The pump curve is not the same kind of thing as a spline
curve specification for an airfoil, where that shape is what will have the
desired aerodynamic properties.
(07)
-Ed
(08)
--
Edward J. Barkmeyer Email: edbark@xxxxxxxx
National Institute of Standards & Technology
Systems Integration Division
100 Bureau Drive, Stop 8263 Work: +1 301-975-3528
Gaithersburg, MD 20899-8263 Mobile: +1 240-672-5800
(09)
"The opinions expressed above do not reflect consensus of NIST,
and have not been reviewed by any Government authority."
(010)
From: ontology-summit-bounces@xxxxxxxxxxxxxxxx
[mailto:ontology-summit-bounces@xxxxxxxxxxxxxxxx] On Behalf Of Matthew West
Sent: Tuesday, March 12, 2013 4:12 PM
To: 'Ontology Summit 2013 discussion'
Subject: Re: [ontology-summit] Hackathon: BACnet Ontology
(011)
Dear Ed,
(012)
I have to disagree. Only some measurement data is easy to exchange, and even
then one must be careful that both the sender and the receiver have a common
understanding of the nature and purpose of the measurement. This includes
simple common sense ideas like agreeing on (and documenting) the units to be
used, or explicitly exchanging units with the numeric measurements. It also
includes agreement on rounding values or stating uncertainties.
(013)
MW: I agree. I meant to say “basic measurement data”. The rest of what you
say is precisely why I said: “By the way, measurements look easy from the
outside, but once you lift the lid, you find all kinds of interesting things
there you can easily get tripped up by.”
(014)
But there is a lot more to the context of a measurement than just the units and
the uncertainty. There are standard sizes that have the same name but temporal
differences in tolerances, and there are considerations like operational state
and ambient temperature and pressure that affect values of the same measurement
of the same thing. And finally, like parametrics, there are measurement values
that are plugged into functions and equations to produce other measurement
values, and it is very important to agree on what those mathematical formulae
are. In the particular case of chemical processes, semiconductor fabrication,
and plastic and metal molding, for example, a group of reference measurements
is used to specify an observed performance curve, while the actual process
depends on accurate depiction of performance at other points on that curves.
Humans often exchange these curves as graphs, but software isn’t good at
turning PNG images into quantitative performance estimations.
(015)
I know for a fact that this last problem is not solved in 15926,
(016)
MW: There is something called multidimensional_property_space which was
intended to handle things like pump curves. Were you aware of that, or have you
tried it and found it wanting? I’d be interested in your experience. The idea
would be to specify sufficient points from the curve that you were happy to
interpolate between them.
Regards
Matthew
(017)
and you don’t want to open the Pandora’s box that is the relationship
between control parameters and performance parameters. This is not, in
general, a solved problem. There are known standard solutions to specific
known problems. The best guidance is to characterize the measurement
information you want to exchange in the context of use and look to see whether
that problem has already been acceptably solved in industry.
(018)
The important ideas in the VIM are (a) that every quantity (in a use) has a
‘quantity kind’ that identifies what quantities it can be compared with,
(b) that no quantity can be known exactly, measurements are comparisons against
reference quantities of the same kind, (c) that units are associated with
quantity kinds and are reference quantities for comparisons. The rest is about
what measurement you made, how you made it, and how accurate you know your
technique to be in that situation.
(019)
There are many cases in which most of these details don’t matter, because
both parties to the exchange understand the intent and typical quality of the
measurement. But there are also many cases in which some of these details do
matter, because the parties to the exchange have different backgrounds and
mental models of the situation. The designer of an airflow system and the
designer of the fans do not have the same model of the problem space. They do
have models that can be aligned for the purpose of their interaction, but they
have to be cognizant of the need for that alignment in their exchanges.
(020)
-Ed
(021)
--
Edward J. Barkmeyer Email: edbark@xxxxxxxx
National Institute of Standards & Technology
Systems Integration Division
100 Bureau Drive, Stop 8263 Work: +1 301-975-3528
Gaithersburg, MD 20899-8263 Mobile: +1 240-672-5800
(022)
"The opinions expressed above do not reflect consensus of NIST,
and have not been reviewed by any Government authority."
(023)
From: ontology-summit-bounces@xxxxxxxxxxxxxxxx
[mailto:ontology-summit-bounces@xxxxxxxxxxxxxxxx] On Behalf Of Matthew West
Sent: Tuesday, March 12, 2013 7:11 AM
To: 'Ontology Summit 2013 discussion'
Subject: Re: [ontology-summit] Hackathon: BACnet Ontology
(024)
Dear Deborah,
Well if you are trying to exchange measurement data, that is relatively easy,
and pointing to parametric design examples as having problems for standards
based exchange, therefore meaning that standards based exchange of measurement
data is difficult is just plain misleading. You can easily exchange measurement
data using ISO 15926 for example, or a number of other standards, usually
labelled SCADA (supervisory control and data acquisition). What is not needed
is another standard for doing this, there are already too many.
By the way, measurements look easy from the outside, but once you lift the lid,
you find all kinds of interesting things there you can easily get tripped up by
– another reason for not reinventing.
(025)
Regards
(026)
Matthew West
Information Junction
Tel: +44 1489 880185
Mobile: +44 750 3385279
Skype: dr.matthew.west
matthew.west@xxxxxxxxxxxxxxxxxxxxxxxxx
http://www.informationjunction.co.uk/
http://www.matthew-west.org.uk/
(027)
This email originates from Information Junction Ltd. Registered in England and
Wales No. 6632177.
Registered office: 2 Brookside, Meadow Way, Letchworth Garden City,
Hertfordshire, SG6 3JE.
(028)
From: ontology-summit-bounces@xxxxxxxxxxxxxxxx
[mailto:ontology-summit-bounces@xxxxxxxxxxxxxxxx] On Behalf Of Deborah
MacPherson
Sent: 12 March 2013 10:11
To: Ontology Summit 2013 discussion
Cc: Ontology Summit 2013 discussion
Subject: Re: [ontology-summit] Hackathon: BACnet Ontology
(029)
Thanks for the response Matthew. You are probably right on target. The thing is
some problems and opportunities should not wait. Creating modular solutions to
keep some information in sets as its transferred would help.
(030)
Toby and I have been talking about "lighter" versions of our standards that are
made for heavy monolithic models. What I like about BACnet as an angle on this
is the transactional nature of collecting and reporting temperatures, tasking
sensors and so forth that are only one small set of information at a time.
(031)
Deborah
(032)
Sent from my iPhone
(033)
On Mar 12, 2013, at 4:46 AM, "Matthew West" <dr.matthew.west@xxxxxxxxx> wrote:
Dear Deborah,
I think the problem, in this case at least, is not quite as you describe.
My understanding is that the issue here was around parametrically defined
objects, where different CAD systems use different parametric functions to
generate objects from their parametric definition. Because of the different
functions, to round trip you would have to wrap the parametric description so
it can be sent to the receiving system, and sent back later. Actually, I think
it would be smarter just to send an identifier that told you the original
object when it came back, but even that does not help you with changes that
have been made to the object in the receiving system with an incompatible
parametric system. The problems are just harder than you would think at a
surface level.
Now this is just an inevitable stage of development. In the early stages, a
thousand flowers bloom, but the vast majority fade. Eventually a few remain,
and it becomes more important (now these are the survivors) that they can
interoperate, than that they retain competitive advantage, so interoperation is
achieved, or a standard developed that customers require them to conform to.
You can see that the state you are pointing to is in the middle of this
process. Eventual completion of the process is pretty much inevitable. The bad
news is that from what I have seen and experienced there is relatively little
you can do to speed the process up (or slow it down) significantly and the
time-scale for the process is decades (or more in some cases), not months or
years.
So the smart thing to do is to recognise where you are, try to encourage
progress through the process, and adopt strategies that recognise the reality
of where you are in the process.
(034)
Regards
(035)
Matthew West
Information Junction
Tel: +44 1489 880185
Mobile: +44 750 3385279
Skype: dr.matthew.west
matthew.west@xxxxxxxxxxxxxxxxxxxxxxxxx
http://www.informationjunction.co.uk/
http://www.matthew-west.org.uk/
(036)
This email originates from Information Junction Ltd. Registered in England and
Wales No. 6632177.
Registered office: 2 Brookside, Meadow Way, Letchworth Garden City,
Hertfordshire, SG6 3JE.
(037)
From: ontology-summit-bounces@xxxxxxxxxxxxxxxx
[mailto:ontology-summit-bounces@xxxxxxxxxxxxxxxx] On Behalf Of MacPherson,
Deborah
Sent: 11 March 2013 21:56
To: Ontology Summit 2013 discussion
Subject: Re: [ontology-summit] Hackathon: BACnet Ontology
(038)
Somewhere in this discussion is a problem that is the essence of what has been
holding up progress in the facilities domain.
(039)
There are ways to publish technical requirements or test for conformance online
for free, and pay (even substantially) to participate in the working groups or
have voting privileges. For example OGC, W3C.
(040)
I can even see being able to own a part name or number within a larger
communication machine that could be mapped to a generic form for broader
exchange purposes. For example “13-57 13 15 Dining and Drinking Spaces”
versus “The Sand Bar and Grille”
(041)
Depending on the domain, or need for cross disciplinary discussion, many on the
IP-protected side have no interest in supporting, or will even actively stops
progress, on a common model. There is also the problem of failed common models
that do not work, will not accommodate different object definitions - from
software to software or industry model to industry model - without loss of data
or functionality. Bentley systems has stepped forward in this white paper on
the IFC model to say actually – the emperor has no clothes on. See pages 6
and 7 “Round Tripping”
(042)
For some reason I think ontologies might be a way these IP-With-Open problems
might be fixed but maybe I am wrong or wishing for too much.
(043)
DEBORAH MACPHERSON
Specifications and Research
(044)
Cannon Design
3030 Clarendon Blvd.
Suite 500
Arlington, VA 22201
(045)
Phone: 703.907.2353
Direct Dial: 2353
(046)
dmacpherson@xxxxxxxxxxxxxxxx
Cannondesign.com
Skype debmacp
(047)
From: ontology-summit-bounces@xxxxxxxxxxxxxxxx
[mailto:ontology-summit-bounces@xxxxxxxxxxxxxxxx] On Behalf Of Simon Spero
Sent: Monday, March 11, 2013 5:25 PM
To: Ontology Summit 2013 discussion
Subject: Re: [ontology-summit] Hackathon: BACnet Ontology
(048)
On Mon, Mar 11, 2013 at 11:53 AM, Peter R. Benson <Peter.Benson@xxxxxxxxx>
wrote:
Deborah, IP is a real issue. We designed the eOTD to try to resolve some of
these issues. In a dictionary the IP resides in the representation but also
in the identifiers or codes as these are always copyright.
(049)
That is not entirely clear; see e.g. SOUTHCO, INC v. KANEBRIDGE CORPORATION (
http://www.ca3.uscourts.gov/opinarch/021243pe.pdf ), where part numbers were
found to be not protected (but see also how Alito takes care to distinguish
Delta Dental )
(050)
Simon
(051)
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