OWL and Reference data

[<mats.nilsson@fmv.se>]

Title: OWL and Reference data

  Hi all,

I'd like to restart a discussion about reference data which if possible should result in a meeting session in Valencia (yes, I'm going there) dedicated to reference data.

The main reason for bringing this topic up again is the need at FMV and the Swedish Defence to create/refresh a dictionary describing military and other common concepts. I've managed to make a number of the largest current projects interested in using OWL as the basic representation of the concepts/terms instead of creating an (e.g. Access based) application or using a simple (Word) document. The presentation to users would be in HTML created by XSL from the OWL-file (just like DEXlib or STEPmod). I believe you all can see some of the benefits this could lead to for us.

Therefore, I'd like to hear your comments on the following issues:
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1.   Label v.s. ID
I feel that the rdf:ID tag must be a unique identifier (within 10303?) which identifies the concept regardless of language. The rdfs:label tag should be used as the human interpreted way to distinguish between different concepts. This could be one way of handeling the 'homonym' problem, e.g. to separate "stone" (a primitive tool/resource for hammering…) from "stone" (a measurement for weight).

<owl:Class rdf:ID="plcs00001">
   <rdfs subClassOf rdf:resource="nnnn" />
   <rdfs:label xml:lang="en">identifier</rdfs:label>
   <rdfs:label xml:lang="se">identifierare</rdfs:label>
   ...
</owl:Class>

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2. Minimum tag definition
We should agree on which of all possible tags and attributes should/must be populated in order for the reference data definition to be complete. This might not be a big task, but it might be an important checklist in the review process.

I guess these should be included;
<dcterms:created rdf:datatype="http://www.w3.org/2001/XMLSchema#string">2005-03-11</dcterms:created>
<dc:creator rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Mats Nilsson, FMV, Sweden</dc:creator>
<dc:source rdf:datatype="http://www.w3.org/2001/XMLSchema#string">DEF-STAN 00-60</dc:source>

… and probably a few others describing version, status (proposed, defined, obsolete..) a.s.o.

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3. Descriptions in different languages
I feel there should be a possibility to include a Swedish descriptive text (the rdfs:comment tag in OWL) to a concept defined e.g. in the PLCS core RDL, e.g. the concept 'Identifier'. This is important for the dictionary functionality described in the introduction above. How can we handle translations of the description? I believe there could also be a need for a Norweigan description, and a German, and…

There is no (as far as I've seen) implemented functionality in Protegé for descriptions in multiple languages. But it might be possible to use the rdfs:comment tag with an xml:lang attribute?! Is this allowed in OWL? Can there be multible rdfs:comment tags according to the schema?

In that case a possible solution is this;

<rdfs:comment rdf:datatype="http://www.w3.org/2001/XMLSchema#string" xml:lang="en">
   Specifies the number of weeks needed.
</rdfs:comment>
<rdfs:comment rdf:datatype="http://www.w3.org/2001/XMLSchema#string" xml:lang="se">
   Anger antal veckor som åtgår.
</rdfs:comment>

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4. 'about'/'ID' issue
Leif discovered in an OWL-file that the concept name sometimes appered in the rdf:ID tag and sometimes in the rdf:about tag. We need to figure ouf if this is a Protegé error or something else. Leif can probably explain this better.

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5. Additional OWL tags
Can additional non OWL tags be used without messing up RDL functionality, e.g. for the versioning of descriptions of concepts and for other 'non standard' meta data regarding concepts. Or is perhaps everything already there?!

Looking forward to hear your comments/suggestions/questions…, and to see you in Valencia!

Regards,
  Mats
..............................................................................
Mats Nilsson – KC Logistik
FMV - Försvarets materielverk
Swedish Defense Materiel Administration
S-115 88 Stockholm, Sweden
tel: +46 8 782 47 24     mobile: +46 70 267 47 24
fax: +46 8 782 65 64     e-mail: mats.nilsson@fmv.se