SIOC/Ontology/UpdateSpring2008

by Sergio Fernández (CTIC), Uldis Bojārs (DERI), Stéphane Corlosquet (DERI) and Thomas Schandl (DERI)

Disclaimer: this document is NOT official and must not be considered as such.

There are many open points that we need to study in order to update the ontology.

General issues

Specification

• there is a new version of SpecGen: SpecGen5
• consider to merge it with Uldis' version
• some new features to improve the specification, mainly its accessibility

Namespaces

• there are many namespaces that are not used
• probably when we moved some classes/properties to types module
• review and clean it

Publishing

mod_rewrite approach

• using mod_rewrite Apache module
• W3C document: Best Practices Recipes for Publishing RDF Vocabularies
• we need to use recipe3
• now we only serve application/rdf+xml
• but must be something like:
  • request over http://rdfs.org/sioc/ns#Forum, Accept: application/rdf+xml
    1. GET /sioc/ns
    2. 303
       Location: /sioc/ns.rdf
    3. GET /sioc/ns.rdf
    4. 200
       Content-type: application/rdf+xml
  • request over http://rdfs.org/sioc/ns#Forum, Accept: text/html
    1. GET /sioc/ns
    2. 303
       Location: /sioc/spec/
    3. GET /sioc/spec/
    4. 200
       Content-type: text/html
• be careful how to implement content negotiation, recipes are not perfect
• Vapour could help to debug it (view actual report)

mod_mime approach

• Richard also suggest that we could use mod_mime Apache module
• we have more information here

Versioning

• it could be good maintain published old versions of the ontology/specification
• like W3C does: this version and last version
• Vit Novacek is working on a document about that
• also use some annotation properties, such as dct:issued, dct:modified, vs:term_status or skos:changeNote

Authors

The authors are missing in the ontology. We can use dc:creator in this way:

http://rdfs.org/sioc/ns# rdf:type owl:Ontology ;
  dc:creator "John Breslin" ;
  dc:creator "Uldis Bojars" ;
  dc:contributor "..." .

Ontology

• allow a broader use of some properties such as sioc:note, sioc:content, sioc:sibling and sioc:num_replies by extending them to sioc:Item (they are currently restricted to sioc:Post) see http://tuukka.iki.fi/tmp/sioc-2008-02-29.html#10:42:56
• also drop the domain of sioc:has_administrator and the range of sioc:administrator_of as they are currently set to sioc:Site but e.g. Yuki needs them also for sioc:Forum

Follow up from last discussion

• Need for earliest_item property linking Container and Item.
• "OWL-ify" SIOC
• Give recommendations on argumentative discussion terms to use from SALT / IBIS / TDL.
• Need for "embeds_knowledge" property to link WikiArticle to a named graph with relevant triples extracted.
• Add properties for Post / Item "status" (private, draft, public, etc.) and for User password
• Look at description for next_by_date as a "given Container" may vary under different circumstances (is it a Thread or a Forum?).

Domains/Ranges

sioc:Role

We need to discuss how to use this class / make it more useful - maybe define a set of right in sioc types?

Related Ontologies

Probaly we need to update classes/properties that use external ontologies. And there is also a document that we need to review and updated.

Dublin Core

After the major updated of last January, it's important to review the relation between SIOC and DC. In summary, all the RDF stuff has been moved to dct, with formal domain/ranges of properties.

sioc:topic

• now (v1.27) we have: #topic rdfs:subPropertyOf dc:subject
• but with new version of DC must be: #topic rdfs:subPropertyOf dct:subject
• or: #topic rdfs:subPropertyOf skos:subject
• or probably the union of dct:subject and skos:subject
• or deprecate it such we did with sioc:title and others

others

The status of dct:created, dct:modified, dct:hasPart and dct:isPartOf didn't change.

FOAF

Nothing important has changed. Probably it could be nice to update and improve the example.

MOAT

• What is the relation between MOAT and our class Tag (sioct:Tag)?

Translations

We want to translate the ontology (rdfs:label and rdfs:comment, probably only in the core) into another languages (Spanish, German, French, Italian, etc.) to make it more accessible.

The idea is include the new triples in the same file:

• split the ontology by languages is not consider a good practice
• there isn't any problem while we maintain the ontology size under 1MB
• if it grows more, we will need to split it by terms (classes and property)

Other issues

Best practices publishing SIOC

• with this update will appear many interesting things
• take all the ideas for this future document
• such as:
  • dct:created/dct:modified issue
  • RDFa section
  • ...