On Freitag, 14. März 2008, Peter Ansell wrote: > On 14/03/2008, S Page <[EMAIL PROTECTED]> wrote: > > Peter Ansell wrote: > > > 1. Why does the semantic mediawiki ontology not use dublin core to > > > subclass its essential properties? > > > > I'm not sure what you mean. SMW doesn't impose a particular ontology on > > annotations (except for its representation of MediaWiki categories). > > However, you can "import" dc terms and tie SMW properties to them so > > that when exported as RDF they use the dc ontology. E.g. an article > > about a research paper that says [[Has author:John Doe]] can export RDF > > <dc:creator ...>John Doe</dc:creator> > > instead of > > <property:creator ...>John Doe</property:Last_page> > > I wouldn't say that dc elements is imposing a particular ontology onto > anyone, it has no side effects, only extra possibilities that are > useful for querying. Just wondering why one would not want to use it, > instead making up a basic vocabulary based on Subjects and Wikipages > when both have been described by skos and dublin core elements/terms > respectively.
I assume you refer to the SWiVT vocabulary that SMW uses (which is, as S rightly said, the only built-in vocabulary that SMW utilises). We are of course happy to reuse existing vocabularies to improve compatibility with other tools. It would be easy enough to import an OWL version of the DC vocabulary. But -- correct me if I am wrong -- I fear that there is no single normative declaration for DC terms in OWL (What is the value range of dc:creator? Is it an AnnotationProperty or a DatatypeProperty? ...). But we certainly welcome concrete proposals on what exactly to import and in which way, we just want to maintain basic compatibility to other semweb tools. Importing other classes would be one option. Would you like to make a list of SWiVT terms that you believe should better derive from SKOS or DC? We can then check what is required in each case. > > Wikipage isn't really an annotation anyway, its a basic part of the > document metadata. What do you mean by "Wikipage"? Do you refer to the property "swivt:page"? SMW usually uses the term "annotation" to refer to things that the user enters, i.e. swivt:page is no annotation in this sense. It is, of course, an owl:AnnotationProperty, but that does not preclude it from being part of the document metadata. Do you refer to some other sense of "annotation" that swivt:page should rather not be? > I would say the subject has a wikipage, which can > have dublin core metadata from the system. It seems that each subject in SMW does "have" a swivt:page already, doesn't it? So do I understand you correctly that you would like to be able to add DC data to that page? Or would you like us to export wiki-metadata about wikipages using DC? > I am not referring to > something that you could create an annotation about easily. Just > wondering whether there were any efforts to exploit the fact that > semantic mediawiki is a wiki, and has the basic document > revision/provenance/contributor/creator metadata elements that can be > best described by the system. We have thought about providing machine-processable exports for existing wiki page metadata as well, but we did not get down to implementing it yet. If you feel like approaching that, we are happy to assist as time permits. > > > > 2. What is being done to make revision histories integrate with the > > > wikipage metadata? Use of FOAF in this area maybe? > > > > SMW annotations are not about the wiki article, they're about the thing > > described by the article. See > > http://semantic-mediawiki.org/swivt/1.0#Subject > > > > There's already MediaWiki code to export article information, see > > http://meta.wikimedia.org/wiki/RDF_metadata > > http://www.mediawiki.org/wiki/Extension:RDF > > However, this code seems disabled in most installations, e.g. > > http://ontoworld.org/wiki.phtml?title=Berlin&action=dublincore > > > > I'm no expert on this stuff, please clarify. > > It would be interesting to utilise MwRdfDcmes from Rdf.php as a part > of the actual annotation that semantic mediawiki outputs, with the > option to turn it off with __NODCMES__ or something similar if the > page author did not want the information publicised. > > It could also be possible if one wanted to dissociate the subject of > the page from the metadata about the page to have these in two > different forms, but it would still be wise to link to them from both > places, ie, say where the document metadata can be found in the > semantic subject stuff and say where the subject of the page can be > found on the document metadata. Yes, exactly. We also though about having different export services for page metadata, so that one could obtain RDF for SMW-data and for wiki-metadata separately (but interlinked). It would even be possible to implement simple content negotiation such that wiki page URLs would directly supply their RDF metadata on request. Of course, one would want separate URIs for all revisions (also to not have to include data about all revisions into each metadata export). This is all not too difficult conceptually, but it requires some work on the technical side that we currently cannot find time for. > > Just some thoughts. Might get in and hack something up when I get a chance. Yes, that would be great. A separate Special page for metadata export could be developed quite independently, and we could then easily integrate it into the system. I have recently extended the OWL/RDF export code to allow easier access outside the current Special:ExportRDF code. We now have an internal OWL/RDF-ish data format that is just serialised by Special:ExportRDF. So in principle it is already enough to create internal RDF data objects, and to leave the serialisation to the existing code (which could be moved to be usable by two special pages). See SVN's special/Export and includes/export for related code. Markus > > Peter > > ------------------------------------------------------------------------- > This SF.net email is sponsored by: Microsoft > Defy all challenges. Microsoft(R) Visual Studio 2008. > http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ > _______________________________________________ > Semediawiki-devel mailing list > Semediawiki-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/semediawiki-devel -- Markus Krötzsch Institut AIFB, Universität Karlsruhe (TH), 76128 Karlsruhe phone +49 (0)721 608 7362 fax +49 (0)721 608 5998 [EMAIL PROTECTED] www http://korrekt.org
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