- From: Hans Teijgeler <hans.teijgeler@quicknet.nl>
- Date: Fri, 13 Oct 2006 07:37:32 +0200
- To: "'Pierre-Antoine Champin'" <swlists-040405@champin.net>
- Cc: <semantic-web@w3.org>, "'Joshua Tauberer'" <jt@occams.info>
Hi Pierre-Antoine, We use n-ary relations (we call them 'templates') such as: <oim:ST-VESSEL-3401-002 rdf:ID="ME03_ST-267634"> <rdfs:label>vessel V-6060 has a design pressure of 100 barg</rdfs:label> <part7:possessor rdf:resource="#ME03_347621-20060306T1357Z"/> <part7:propertyType rdf:resource="http://www.15926.org/2006/02/part4#DesignPressure"/> <part7:numericalValue rdf:resource="#XSFL_100"/> <part7:unitOfMeasure rdf:resource="http://www.15926.org/2006/02/part4#Barg"/> </oim:ST-VESSEL-3401-002> <part4:XmlSchemaFloat rdf:ID="XSFL_100"> <part2:content rdf:datatype="http://www.w3.org/2001/XMLSchema#float">100</part2:content> </part4:XmlSchemaFloat> For each template class we define, in OWL, the Restrictions on its properties. The 'possessor' is a "temporal part" of ME03_347621 (that temporal part has been declared separately). 'DesignPressure' and 'Barg' are defined in our Reference Data vocabulary, as per ISO 15926-4. The numericalValue is an instance of XmlSchemaFloat, with a 'content' property expressed in the XML Schema float datatype. In forementioned Reference Data vocabulary we also have defined the relationship between Pressure and the Scale, and between that Scale and its NumberSpace (here: -1 to +infinity). So our software can validate whether or not the value of 100 falls in that instance of NumberSpace. You, and other readers and contributors of this forum may think this is too complex. But this is only a simple problem :-) Try to represent a specification for a centrifugal compressor or the like, in such a way that the computer system of a supplier at the other end of the world, who doesn't know you, can extract exactly what you mean. And 20 years later some engineering outfit, handling a revamp of the plant, still can understand what you meant. Text and pictures are a lot simpler (for humans), we still can understand what Shakespeare wrote or Rembrandt painted.The main problem is that today's computer systems are still rather unintelligent (as compared to the capabilities of the human brains). The problem with data is that they are almost always implicit, i.e. we leave out a lot of information because we assume that the (human) recipient can fill in the relationships between the data based on the context (e.g. it is on the same document) and on domain expertise. OWLites will say that we have reasoners for that, but I don't believe that any manager will be willing to rely on their outcome. So we (the process industries) decided, almost 20 years ago, to make our exchange information as explicit as is reasonably possible in order to make it more understandable for computers, and to allow for integration of lifetime information about an entire plant, its components, and its streams. All of that in a neutral format that is vendor-independent. The Semantic Web, with its RDF and OWL (Full!), SPARQL, and SOAP, has come in our world at the right time. We love it! But if N years from now the IT industry has totally forgotten these technologies (remember COBOL?) our lifetime data can easily be migrated to whatever gizmo's are then the utter wisdom. Because we rigorously modelled them. I'll get off that soapbox :-) Regards, Hans PS to ISO 15926 insiders: the above example has been amended somewhat for editorial reasons. ____________________ OntoConsult Hans Teijgeler ISO 15926 specialist Netherlands +31-72-509 2005 www.InfowebML.ws hans.teijgeler@quicknet.nl -----Original Message----- From: semantic-web-request@w3.org [mailto:semantic-web-request@w3.org] On Behalf Of Pierre-Antoine Champin Sent: Thursday, October 12, 2006 11:27 To: Joshua Tauberer Cc: semantic-web@w3.org Subject: Re: ontology for units of measurement and/or physical quantities Joshua Tauberer a écrit : > The big drawback is that dealing with these literals requires a > special parser, but it saves creating a new bnode for each measure (i.e. > mysphere mass [ grams 1000 ] ) and I think is a little easier to > understand compared to having a bnode that represents the notion of > the mass itself independent of its measure. There is indeed a tradeoff to find between encoding things in "complex" literals and making them explicit in resources. Note that checking the consistency of measurements as blank nodes requires ad-hoc implementation as well : it is not possible to state that any resource with :grams "1000" must have :kg "1"... An the problem of rounding remains... pa -- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.0.408 / Virus Database: 268.13.2/472 - Release Date: 11-Oct-06 -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.0.408 / Virus Database: 268.13.2/472 - Release Date: 11-Oct-06
Received on Friday, 13 October 2006 05:38:12 UTC