COMPUTER SUPPORTED COLLABORATIVE KNOWLEDGE

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1 COMPUTER SUPPORTED COLLABORATIVE KNOWLEDGE BUILDING : P2P SEMANTIC WIKIS APPROACH Hala Skaf-Molli ECOO Team Associate Professor Nancy-University skaf@loria.fr

2 AGENDA General Introduction to CSCW Collaborative knowledge building process Collaborative knowledge building tools Wikis Semantic Wikis P2P Semantic Wikis Conclusion

3 WIKIS Wikis are the most popular collaborative knowledge building editors Web-based content management systems Ward Cunningham et al. The Wiki Way: Quick Collaboration on the Web Wikis are Social software Everyone can participate in building global knowledge Quality is the result of social filtering, discussion, negotiation

4 WIKIS Wiki are simple to use No technical skills Wikipedia: 10 million articles 6.8 million of registered users In the Top 10 of Web sites

5 EDITING WIKI PAGE Simplified markup language, sometimes known as "wikitext» "WYSIWYG" ("What You See Is What You Get") Source:

6 LINKING AND CREATING PAGES Links are created using a specific syntax, the socalled "link pattern» Link pattern : CURIE Page name and link CamelCase : pretty rendering "free linking" using brackets, and some disable CamelCase by default.

7 EDITING CONFLICT Comparison of Optimistic Approaches to Collaborative Editing of Wiki Pages. Claudia Ignat, Gérald Oster, Pascal Molli, et al. CollaborateCom2007

8 EDITING CONFLICT

9 SCENARIO WITH MEDIA WIKI

10 VERSION Version Changes are logged Every version of a page is stored Revert: mistake or vandalisme

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12 NAVIGATION Hypertext links to other pages Non-linear navigation Facilate navigation Category and tags Backlink (incoming link) : dispaly all pages that link to a given page In wikipedia Page Category: as a directory to structure articles organize and structure the content of the wiki update automatic with bot In the article page: [[Category:Wiki]]

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14 WIKIS DRAWBACKS Search and reuse: Not easy to find information Not reusable by machine Many pages are maintained by humans but it can be generated by computers (matrix pages, lists pages) Centralized architecture: Content is unavailable in case of failure Scalability Performances Collaborative editing No Off-line work, mobile editing No transactional changes: no atomic changes across multiple pages

15 WIKIS EVOLUTIONS

16 SEMANTIC WIKIS Objective Structure the Wikis for better search and navigation How? Machine accessible Efficient data search Reusable knowledge Adding formal structures to wikis By using Semantic Web technologies : RDF, SPARQL Integrate RDF requests in wiki pages to generate content.

17 WHAT IS RDF? RDF (Resource Description Framework) is a general data model to represent knowledge in a distributed world It allows to represent any type of knowledge By decomposing it into small pieces (triple), with some rules about the semantics, or meaning, of those pieces. A fact is expressed as a triple (statment) of the form (Subject, Predicate, Object) I own my_appartment More detail: rdfabout.com

18 URI Names for subjects, predicates, and objects must be Uniform Resource Identifiers (URIs)

19 RDF GRAPH

20 SPARQL SPARQL is a query language for RDF Four types of queries: SELECT, ASK, DESCRIBE, and CONSTRUCT.

21 QUESTION

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24 Buffa et al. SweetWiki: A Semantic Wiki. Journal of Web Semantic, 6(1), 2008.

25 THE USE OF ONTOLOGIES FOR WIKIS Require existing ontology to be loaded Each page has a type Special interface to edit and visualize semantic data Examples: IkeWiki, SweetWiki Schaffert. IkeWiki: A Semantic Wiki for Collaborative Knowledge Management. WETICE, IEEE. Buffa et Al. SweetWiki: A Semantic Wiki. Journal of Web Semantic,6(1),2008.

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27 IKEWIKI Too rigid for emergent domains No established ontologies

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29 THE USE OF WIKIS FOR ONTOLOGIES No predefined ontology Annotations are embedded in wiki text One subject for one page Semantic Media Wiki (SMW) Extension of MediaWiki [[predicat::objet]] Vôlkel et al. Semantic Wikipedia. 15th International Conference on World Wide Web, (WWW), ACM.

30 '''London''' is the capital of [[capital of::england]] and of the [[capital of::united Kingdom UK]]. As of [[2005]], the total resident population of London was estimated [[population:=7,421,328]]. Greater London covers an area of [[area:=609 square miles ]]. It is in [[located in::england]] in the [[situated in::europe]]. [[Category:City]]

31 SEMANTIC MEDIAWIKI Annotations in context Human readable annotations Machines accessible annotations Enable the emergence of Ontology

32 SEMANTIC WIKIS Better search and navigation Machine accessible knowledge But still centralized Performance for semantic queries Availability, Scalability No Off-line work No transactional changes : atomic changes across multiple pages.