Yes – all of that –in the manufacturing process tolerances are very precise, less than the width of a human hair. I’ve seen structural engineer’s be very concerned over a 2 mm creep in a survey. Many purposes of exchanging measurable, modeled, design or production information versus results in the real world, as built, do need to be very precise. Both in the models and in the executed results.
However, similar to geospatial being able to zoom in and out apparently seamlessly, sometimes using vectors, sometimes using faceted curves and points to just look enough like a curve - BIM and mechanical-electrical-plumbing systems inside real buildings (which might be specified and conform to BACnet), need a way to exchange basic geometries with looser tolerances. Just getting a fire fighter to the right room is enough, someone renting a studio apartment at XX sq.ft. is not going to get out a laser measure the way a GSA leasing agent might.
GSA does have some rules about “…..agreement on rounding values or stating uncertainties”. 95% of all other lifecycle exchange partners probably could not care less about precision, or even know why a stated uncertainty might matter to them outside of the telephone game problem where each next retelling changes just a little more and more.
To align, up to, 10 models for interaction that would take a building layout from a digital fire panel, “enlivened” by sensor data, put into a message on the wire, and displayed on a mobile data computer – is going to need to be very generalized curves. That is why the background IE last known configuration of a building needs to be static, a PDF or JPG, only the location of sensor information needs to be dynamic, messages being transported over wires only need a “hint” of this measured, modeled, building.
DEBORAH MACPHERSON
Specifications and Research
Cannon Design
3030 Clarendon Blvd.
Suite 500
Arlington, VA 22201
Phone: 703.907.2353
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From: ontology-summit-bounces@xxxxxxxxxxxxxxxx [mailto:ontology-summit-bounces@xxxxxxxxxxxxxxxx] On Behalf Of Barkmeyer, Edward J
Sent: Tuesday, March 12, 2013 2:45 PM
To: Ontology Summit 2013 discussion
Subject: Re: [ontology-summit] Hackathon: BACnet Ontology
Matthew,
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.
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.
I know for a fact that this last problem is not solved in 15926, 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.
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.
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.
-Ed
--
Edward J. Barkmeyer Email: edbark@xxxxxxxx
National Institute of Standards & Technology
Systems Integration Division
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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.
Regards
Matthew West
Information Junction
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This email originates from Information Junction Ltd. Registered in England and Wales No. 6632177.
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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.
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.
Deborah
Sent from my iPhone
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.
Regards
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/
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.
Somewhere in this discussion is a problem that is the essence of what has been holding up progress in the facilities domain.
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.
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”
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”
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.
DEBORAH MACPHERSON
Specifications and Research
Cannon Design
3030 Clarendon Blvd.
Suite 500
Arlington, VA 22201
Phone: 703.907.2353
Direct Dial: 2353
dmacpherson@xxxxxxxxxxxxxxxx
Cannondesign.com
Skype debmacp
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
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.
That is not entirely clear; see e.g. SOUTHCO, INC v. KANEBRIDGE CORPORATION (