Enabling cross-wikis integration by extending the SIOC ontology

Enabling cross-wikis integration by extending the SIOC ontology SemWiki 2009 – ESWC Fabrizio Orlandi1 (June 1, 2009) Alexandre Passant2 1 Università di Modena e Reggio Emilia 2 Digital Enterprise Research Institute, Galway

Interlinking wikis All wikis share a wide common knowledge, but they have different structures and implementations, platform dependent. TWiki DokuWiki MoinMoin There are lots of wikis and they are all disconnected...

Many isolated communities of users and their data Wikis are also disconnected with other social media websites * Source: Pidgin Technologies, www.pidgintech.com

Interlinking wikis Several semantic models have been implemented and used within specific semantic wiki platforms e.g.: Semantic MediaWiki as well as efforts to create generic ontology models: •WikiOnt ontology (DERI) •WIF (Wiki Interchange Format) ontology (Max Völkel et al.) ) But they are all specific to wikis and not open to other social websites

SIOC Semantically- Semantically-Interlinked Online Communities • A project developed by DERI to semantically describe the content and structure of community sites • In particular the SIOC ontology is not specific to wikis and is widely used on the Web • It aims to create new connections between online discussion posts and items, forums, blogs... and wikis. • Adopted in a framework of more than 50 applications, deployed on over 400 sites http://sioc- http://sioc-project.org

Extending the SIOC ontology We decided to extend the SIOC ontology to make it compliant with wikis and make wikis interoperable and linkable to other social objects. objects. First we considered the typical and relevant features of wikis in terms of structure and social interactions. interactions. Modeling these features using SIOC would have other advantages: advantages: • Integration with existing SIOC data, as well as interlinking with other RDF data for advanced querying purposes; purposes; •Ability to run the same SPARQL query to find items on a particular wiki site or on a weblog or a forum. forum.

Relevant wiki features • Multi-authoring: multiple users edit the same content simultaneously. Multi- simultaneously. Feature modeled using the class sioc:User (subclass of foaf:OnlineAccount as foaf:OnlineAccount) object of sioc:has_creator that describes a user account in an online community site. In this way a foaf:Person can be linked to several sioc:User belonging to different wiki sites.

Relevant wiki features • Categories: Categories: sets of articles on related topics which are hierarchically organized. organized. A solution is provided by the SKOS vocabulary, as it offers a way to model hierarchical structures between various categories, as instances of skos:Concept. skos:Concept. Hence we defined the sioct:Category class as a subclass of skos:Concept. sioct: skos:Concept.

Relevant wiki features • Social Tagging: non-organized but dynamic organization process. Tagging: non- process. The properties sioc:topic (using URIs) and dc:subject (using keywords) can be sioc: dc: used to represent tags related to a particular wiki page. page. http://wiki.../The_Clash sioc:topic http://wiki.../punk_rock dc:subject tag:hasTag Punk rock

Relevant wiki features • Discussions: pages where people can discuss about the article subject. Discussions: subject. We added a new sioc:has_discussion property, with domain sioc:Item and open range (to make this property reusable).

Relevant wiki features • Backlinks: (or “what links here”) wiki internal links pointing to the same Backlinks: here”) wiki article. article. We modeled this feature using the already existing sioc:links_to property sioc: (subproperty of dcterms:references). dcterms:references)

Relevant wiki features • Pages Versioning: each page has an associated page history. In order to define an essential and lightweight model we: • Added a sioc:latest_version property; • Added 2 transitive properties: sioc:earlier_version & sioc:later_version;; • Defined sioc:later_version as inverse property of sioc:earlier_version;; • Defined sioc:next(previous)_version as subproperty of sioc:later(earlier)_version. .

SIOC- SIOC-MediaWiki Exporter An exporter from a popular wiki platform to expose data in RDF using our proposed model. model. A webservice, written in PHP, that exports a MediaWiki article in RDF, publicly available at: at: http://ws.sioc- http://ws.sioc-project.org/mediawiki/

Browsing the generated data RDF data extracted from a wiki page is browsable with tools such as The Tabulator To offer a better browsing experience and ease the process of crawling SIOC exports of MediaWiki instances, the webservice automatically produces instances, rdfs:seeAlso links between wiki pages, following the Linked Data practices; rdfs: pages, practices; Link to the corresponding Dbpedia resource added automatically, if the article is from the Wikipedia [English] (with foaf:primaryTopic) foaf:primaryTopic) A RDF crawler can easily follow all the seeAlso links found on every document and continue to crawl, so it is possible to crawl an entire wiki site starting from a single URI.

Advanced querying process To evaluate our proposal, we exported and crawled different MediaWiki proposal, instances: instances: 4 wikis have been crawled, collecting more than 1GB of RDF data. crawled, RDF data loaded in a triple-store: Sesame + OWLIM triple-store: SPARQL queries for a single wiki: wiki: ”what are the collaborating users that worked alternatively on the same wiki article?” article?” SELECT DISTINCT ?wikiArt ?Contrib_a ?Contrib_b WHERE { ?x sioc:latest_version ?wikiArt . ?wikiArt sioc:earlier_version ?VersA . ?VersA sioc:earlier_version ?VersB ; dc:contributor ?Contrib_a . ?VersB sioc:earlier_version ?VersC ; dc:contributor ?Contrib_b . ?VersC dc:contributor ?Contrib_a . FILTER (?Contrib_a != ?Contrib_b ) . }

Advanced querying process SPARQL cross-wikis querying cross- ”Identify pages created by the same user between different wikis”: SELECT DISTINCT ?creator1 ?page1 ?page2 ?wiki1 ?wiki2 WHERE { ?page1 sioc:has_container ?wiki1 ; dc:contributor ?creator1 . ?page2 sioc:has_container ?wiki2 ; dc:contributor ?creator2 . FILTER ( str ( ?creator1 ) == str ( ?creator2 ) ) . FILTER ( str ( ?wiki1 ) != str ( ?wiki2 ) ) . } ”Cross-sites querying by combining FOAF and SIOC”: Cross- SELECT DISTINCT ?content WHERE { <http://example.org/js#me> foaf:holdsAccount ?account . ?account rdf:type sioc:User . ?content sioc:has_creator ?account . }

Conclusion Overview: Presented how the SIOC ontology and lightweight semantics can be used and extended to represent the structure of wikis in an unified way; Described how we designed a webservice to translate any MediaWiki page into SIOC data, following the Linked Data best principles; Provided examples on how this data could be efficiently used for querying purposes. What's next? Further developments may include exporters and plug-in for other plug- platforms to enable better cross-wikis integration; cross- To extend the pages versioning system defined in SIOC regarding wikis to other user-generated content; user- The modeling of a wiki page might be improved adding more details about the content of the article itself.

Thank you! Any questions?

Enabling cross-wikis integration by extending the SIOC ontology

by Fabrizio Orlandi on Jun 06, 2009

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Enabling cross-wikis integration by extending the SIOC ontology — Presentation Transcript