TR: [protege-owl] Re: [Fwd: Units ontology]

For what it's worth, some ideas about units ontology, forwarded from Protégé list

Bernard

-----Message d'origine-----
De : Bernard Vatant [mailto:bernard.vatant@mondeca.com]
Envoyé : lundi 27 décembre 2004 10:14
À : protege-owl@SMI.Stanford.EDU
Objet : RE: [protege-owl] Re: [Fwd: Units ontology]


Hello Michel

Some ideas concerning the questions at the end of your message, although I agree with
Natasha in her answer that harmonization is a job for W3C SWBP group.

You write

> Instead of say: class door has height 2.10, you want to be able to say class
> door has height 2.10 metres.

Sure, and maybe many more in an industrial environment, such as :
- Measurement error (or fabrication tolerance) is +/- 5 mm
- Measurement or fabrication device used to obtain this
- Conditions of the measurement, if you want to track why this door does not close
properly : where, who, when, physical conditions of measurement (temperature, stress,
humidity level ...) etc ...

In short, a measure is certainly better off represented in OWL as an object
(owl:Individual) of generic class "ex:Measure" or one of its subclasses like "ex:Height",
to which you can further attach all this variety of information : unit, value, error,
date, device, physical conditions (themselves a set of measures) ...

And the relation between the measured object and its measure will then be represented as
an ObjectProperty.

Of course, in the "simple" situation of your example, it might be that only unit and value
are relevant or known, although not taking other ones into account might result in a door
not closing or opening properly when the weather gets too hot or wet :))

So certainly what we need is a simple ontology of measurement, that can afterwards be
extended to specific fields of applications, which often need a very small set of

Hope that helps

Bernard

**********************************************************************************

Bernard Vatant
Senior Consultant
Knowledge Engineering
bernard.vatant@mondeca.com

"Making Sense of Content" :  http://www.mondeca.com
"Everything is a Subject" :  http://universimmedia.blogspot.com

**********************************************************************************

> -----Message d'origine-----
> De : protege-owl-bounce@crg-gw.Stanford.EDU
> [mailto:protege-owl-bounce@crg-gw.Stanford.EDU]De la part de Bohms,
> Michel
> Envoyé : mercredi 22 décembre 2004 08:54
> À : protege-owl@SMI.Stanford.EDU
> Objet : [protege-owl] Re: [Fwd: Units ontology]
>
>
> It's good to see such interest in harmonising semantics for measures/units.
> Units and decomposition are IMHU the two top priorities you have to add to
> plain owl to get more a priori interoperable and usefull ontologies.
>
> So, I would be in favour of a place where this is harmonized. Personally I
> hoped that this place would be W3C phase 2 of the semantic web activity since
> you could consider it as a kind of 'best practices' harmonization. However its
> not there...so I think a good second option would be the protégé community...
>
> There is one thing that worries me a bit when looking at earlier
> proposals...they are so complex ! Especially for all eBusiness/eCommerce
> related applications, I think we should try to find the most simple but still
> usefull way to specify a unit. When trying to stay as owl-compliant as possible
> you end up with a requirement that most of the time you want to say something
> about a datatype property.
>
> Instead of say: class door has height 2.10, you want to be able to say class
> door has height 2.10 metres.
>
> We now use ourselves annotation properties (on datatype properties) to do this
> but clearly (see earlier threads) this has disadvantages since those ann.
> properties cannot be assumed interpreted.
>
> Clearly practical simple solutions like:
> - Class door has height-in-metres of 2.10, or
> - Class door has height of '2.10 metre' (ie string datatype that need
> beyond-owl parsing to be understood)
>
> Are also far from ideal, to put it mildly.
>
> But having a complex one (like the unitDIM.owl with 60 classes) migth be a bit
> too much...maybe I just wrong here...does someone has an unitDIM.owl example
> involving one class and one property with a certain unit ? (like my trivial
> door example). The point is I am often not interested what are all allowed
> units for a cerain quantity but in the first place' what is the actual choosen
> unit for my property).
>
> Looking forward to comments on this but even more on some harmonized way of
> handling units pref. as simple as possible but clearly not TOO simple.
>
> Cheers Michel Bohms
>
>
>
>
>
> H.M. (Michel) Böhms
> TNO Building and Construction Research
> Email:  M.Bohms@bouw.tno.nl
> Phone:  +31 15 276 3107
> Fax:    +31 15 276 3024
>
>
> Visiting Address:
> Van Mourik Broekmanweg 6
> 2628 XE Delft
> The Netherlands
>
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>
>
> The disclaimer that applies to e-mail from TNO Building and Construction
> Research can be found on http://www.tno.nl/disclaimer/email.html
>
> -----Original Message-----
> From: Sven Schade [mailto:AbovetheRim@gmx.de]
> Sent: Tuesday, December 21, 2004 2:01 PM
> To: protege-owl@SMI.Stanford.EDU
> Subject: [protege-owl] Re: [Fwd: Units ontology]
>
> I work on formalisations of Measurement Theory for quite a while. Apart from
> kinds of measurement scales and restrictions on operation-calls allowed on
> available data sets, unit systems play a major role.
> Up to now I checked the web for existing ontologies in this area and found a
> huge amount of ontologies about units. The already mentioned SUMO is a good
> example, but there are some alternatives around, e.g. a SEEK ontology
> (http://cvs.ecoinformatics.org/cvs/cvsweb.cgi/seek/projects/kr-sms/OWLOntologies
/Units.owl).


So far, I have a few remarks:

- I am not sure, if they are a good example for standardisation efforts,
because it leaks applications where different projects use the same
ontology. If people can agree on a shared ontology before exchanging
measurement data, fine. But what if two data sources are related to varying
unit-ontologies?

- The use of transformations between units will also become important in
order to maximize automatisation in data integration and in service
compositions.

- I would appreciate to have a discussion platform on ontologies (especially
on those related to observations and measurements).

Cheers,
Sven

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Received on Monday, 27 December 2004 09:20:43 UTC