The NIST ontology defines 4 basic classes that are great:
_qudt:QuantityKind [11]_, _qudt:Quantity [12]_, _qudt:QuantityValue [13]_, _qudt:Unit [14]_ but the properties set leaves me a bit thirsty. Take "Area" as an example. I'd like to reference properties named .ft2 and .m2 so that, for instance, an annotation might be [[Leasable area.ft2::12345]]. To state the precision applicable to that measurement, might be [[Leasable area.ft2:fractionDigits :: 0]] to indicate say, rounding. However, in the NIST ontology, there is no "ft2" property at all -- this is an SI unit though, so it seems identifying first the system of measurement units, and then the specific measurement unit is not a great idea because these notations are then divorced from the property name itself, a scenario guaranteed to cause more user errors & omissions I think. Someone's mentioned uncertainty facets, so I suggest these from the qudt ontology: Property: .anyType:relativeStandardUncertainty Property: .anyType:standardUncertainty Other facets noted might include Property: .anyType:abbreviation Property: .anyType:description Property: .anyType:symbol -john On 19.12.2012 08:10, Herman Bruyninckx wrote: > On Wed, 19 Dec 2012, Denny Vrandečić wrote: > >> Martynas, could you please let me know where RDF or any of the W3C standards covers topics like units, uncertainty, and their conversion. I would be very much interested in that. > > NIST has created a standard in OWL: "QUDT - Quantities, Units, Dimensions and Data Types in OWL and XML": > <http://www.qudt.org/qudt/owl/1.0.0/index.html [5]> > > I fully share Martynas' concerns: most of the problems that are being > discussed in this thread (and that are very relevant and interesting) > should not be solved with an "object oriented" approach (that is, via > properties of objects, and "inheritance") but by semantic modelling (that > is, "composition" of knowledge). For example, one single data base > representation of a unit can have multiple "displays" depending on who > wants to see the unit, and in which context; the viewer and the context are > rather simple to add via semantic primitives. For example, the "Topic Map" > semantic standard would fit here very well, in my opinion: > <http://en.wikipedia.org/wiki/Topic_map [6]>. > >> Cheers, Denny > > Herman > http://people.mech.kuleuven.be/~bruyninc> Tel: +32 16 328056 Vice-President Research euRobotics <http://www.eu-robotics.net [7]> Open RObot COntrol Software <http://www.orocos.org [8]> Associate Editor JOSER <http://www.joser.org [9]>, IJRR <http://www.ijrr.org [10]> > > _______________________________________________ > Wikidata-l mailing list > Wikidata-l@lists.wikimedia.org > https://lists.wikimedia.org/mailman/listinfo/wikidata-l [1] Links: ------ [1] https://lists.wikimedia.org/mailman/listinfo/wikidata-l [2] http://www.mail-archive.com/wikidata-l@lists.wikimedia.org/msg00056.html [3] http://www.mail-archive.com/wikidata-l@lists.wikimedia.org/msg00750.html [4] http://wikimedia.de [5] http://www.qudt.org/qudt/owl/1.0.0/index.html [6] http://en.wikipedia.org/wiki/Topic_map [7] http://www.eu-robotics.net [8] http://www.orocos.org [9] http://www.joser.org [10] http://www.ijrr.org [11] http://www.qudt.org/qudt/owl/1.0.0/qudt/index.html#QuantityKind [12] http://www.qudt.org/qudt/owl/1.0.0/qudt/index.html#Quantity [13] http://www.qudt.org/qudt/owl/1.0.0/qudt/index.html#QuantityValue [14] http://www.qudt.org/qudt/owl/1.0.0/qudt/index.html#Unit
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