Using Ontologies to Strengthen Folksonomies and Enrich Information Retrieval in Weblogs

October 24, 2009 Using Ontologies To Strenghten Folksonomies and Enrich Information Retrieval in Weblogs - ICWSM 2007 1

Using Ontologies to Strengthen Folksonomies and Enrich Information Retrieval in Weblogs

Alexandre Passant EDF, Recherche & Développement, Clamart, France Université Paris 4, Laboratoire LaLICC, Paris, France


1 Corporate Blogging


Classical (old-school) information systems

•  Features: •  Workflows •  Access Control •  Templates •  Archives

•  Designed to store: •  Project reports •  Internal notes •  Hierarchical information

•  But, what about informal and unstructured content: •  Short news •  E-mails •  Coffee-break discussions


A new vision: Enterprise 2.0

•  Web 2.0 concepts in a corporate environment

•  Write and share any knowledge:

•  Blogs •  Comments, trackbacks

•  Re-use and capitalize knowledge:

•  Wikis •  Open structure and cooperation

•  Be informed:

•  RSS feeds •  Shared subscriptions


EDF R&D Experiment

•  EDF R&D: •  2000 researchers •  3 research centers

•  Our platform: •  RSS subscription system •  Blogs •  Group wikis

•  Experiment (1 1/2 year): •  1500 feeds, 8000 blog posts •  80 bloggers, 600 readers / subscribers


2 Weblogs Indexing and Folksonomies


Indexing blog posts

•  Meta-data about the container:

•  Automatically-created metadata: •  Author, creation date, title

•  DublinCore standards •  Meta-data about blog post content:

•  Previously-defined: •  Ontologies, taxonomies

•  User-defined: •  Free keywords and folksonomies

•  Folksonomies: •  Easy to adopt •  Build from scratch


Folksonomies limits

•  Tags variation: •  Different tags for the same meaning:

•  Synonymy, Abbreviation, Acronyms … •  Typos

•  Tag ambiguity: •  Different meanings for the same tag:

•  Acronyms, Homonymy …

•  Flat organisation: •  No way to suggest related tags

•  Paris / France •  blog / socialsoftware


Ambiguity example from del.icio.us


Some tools to reduce variation and explosion

•  Tag completion: •  Forward and “backward” completion •  AJAX

•  Tag suggestion: •  Based on blog post content •  Suggesting existing tags •  But also new ones using named entites extraction •  AJAX


3 The Semantic Web


A Few Words About the Semantic Web

•  Semantic Web

•  Extending the current Web •  Unified description of resources

•  Ontologies

•  Representation of a domain •  Common vocabulary

•  Languages

•  Modeling: RDF(S), OWL … •  Querying: SPARQL …


Weblogging and the Semantic Web

•  Tools: •  Snippet Manager [Cayzer & al. 2005] •  semiBlog [Möller & al. 2006]

•  Folksonomies: •  Tag ontology to represent connections between tags [Newman 2005] •  Tagging model [Gruber 2005]

•  Vocabularies:

•  RSS 1.0 based on RDF, can be extended with other vocabularies •  SIOC: Semantically-Interlinked Online Communities [Breslin & al. 2005]

•  State of The Art: •  « What next for Semantic Blogging » [Cayzer 2006]


4 Strengthening Folksonomies


A mix of Folksonomies and Ontologies

•  Mixing both approaches •  Keep the open spirit of folksonomies •  Use an ontology layer as a formal way to represent data •  Remove ambiguity and add meaning to tags to enhance search experience

•  How ? •  Link tags to domain ontology concepts (classes / instances) •  Create links between posts and ontology concepts using SIOC

•  First steps •  Analyse the folksonomy and most popular tags •  Create a core ontology (based on PROTON) and its instances •  300 classes, 600 instances, mainly named entities


A simple way to link tags to ontology instances


From Tags to Ontology (1/5)

1)  Create and tag post




2)  Link tag to ontology





3)  Link post to ontology






4)  Create new post






4)  Create new post

5)  Infer related post


Dealing with ambiguity and maintaining instances

•  User interface to remove ambiguity when adding a new post

•  Ability to browse the ontology to link to other class / instance for new / different meaning tags

•  Restricted back office to create new instances


5 Enhanced Information Retrieval


A Semantic Search Engine

•  Decentralized data:

•  Ontologies •  Blog posts w/ RDF description •  A central 3store w/ SPARQL

•  Using tags / ontology links to:

•  Deal with tags variations •  Remove ambiguity


Suggesting related tags and posts

•  Goal:

•  Offer suggestions to users based on their current tag search •  Let users discover potential interesting posts •  Different approaches, use both tagging and ontologies:

•  Using instances co-occurrence •  Using instances type •  Defining specific rules

•  Run on the fly and suggest results, using SPARQL


Using instances co-occurrence

•  Basic approach:

–  Posts sharing concepts

–  Ontology to remove ambiguity


Using instances types

•  Suggesting instances of the same class:

–  Programming languages

–  Energy companies


Defining specific rules

•  Rule(s) for each class

•  Location / {sub|top}locations •  Company / companies working

in the same area


Rule example

•  RDF rule {! :x rdf:type sioc:post .! :y rdf:type sioc:post .! :x sioc:topic :a .! :y sioc:topic :b .! :a rdf:type ptop:Agent .! :b rdf:type ptop:Agent .! :a company:expertiseIn :d .! :b company:expertiseIn :d !} => {! :x sioc:related_to :y !} .

•  Reformulated w/ SPARQL SELECT ?post ?topic ?domain!WHERE {! <$uri> [! rdf:type ptop:Agent ;! company:expertiseIn ?domain! ] .! ?post sioc:topic ?topic .! ?topic [! rdf:type ptop:Agent ;! company:expertiseIn ?domain! ] !}


Running and Displaying results

•  SPARQL queries on the triplestore

•  Offering different tagclouds to split results in clusters:

•  Instances •  Specific rules •  Co-occurrence

•  Let users know why they should have a look to related posts


6 Conclusion


Conclusion

•  Mixing folksonomies and ontologies •  Keep simplicity of free tagging •  Ontologies to reduce limits of free tagging •  Infer related posts / topics •  A mix of top-down and bottom-up approach

•  A real use-case •  Adapt model and interfaces to users needs

•  Future works •  Knowledge extraction from weblogs •  Use wikis to add properties to ontology instances •  New ways to browse and query blog posts


Thank you !

Technology

Using Ontologies to Strengthen Folksonomies and Enrich Information Retrieval in Weblogs