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

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

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

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

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

2
Weblogs Indexing and Folksonomies
6 October 24, 2009 Using Ontologies To Strenghten Folksonomies and Enrich Information Retrieval in Weblogs - ICWSM 2007

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

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

Ambiguity example from del.icio.us
9 October 24, 2009 Using Ontologies To Strenghten Folksonomies and Enrich Information Retrieval in Weblogs - ICWSM 2007

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

3
The Semantic Web
11 October 24, 2009 Using Ontologies To Strenghten Folksonomies and Enrich Information Retrieval in Weblogs - ICWSM 2007

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

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

4
Strengthening Folksonomies
14 October 24, 2009 Using Ontologies To Strenghten Folksonomies and Enrich Information Retrieval in Weblogs - ICWSM 2007

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

A simple way to link tags to ontology instances
16 October 24, 2009 Using Ontologies To Strenghten Folksonomies and Enrich Information Retrieval in Weblogs - ICWSM 2007

From Tags to Ontology (1/5)
1) Create and tag post
17 October 24, 2009 Using Ontologies To Strenghten Folksonomies and Enrich Information Retrieval in Weblogs - ICWSM 2007

From Tags to Ontology (2/5)
1) Create and tag post
2) Link tag to ontology
18 October 24, 2009 Using Ontologies To Strenghten Folksonomies and Enrich Information Retrieval in Weblogs - ICWSM 2007

From Tags to Ontology (3/5)
1) Create and tag post
2) Link tag to ontology
3) Link post to ontology
19 October 24, 2009 Using Ontologies To Strenghten Folksonomies and Enrich Information Retrieval in Weblogs - ICWSM 2007

From Tags to Ontology (4/5)
1) Create and tag post
2) Link tag to ontology
3) Link post to ontology
4) Create new post
20 October 24, 2009 Using Ontologies To Strenghten Folksonomies and Enrich Information Retrieval in Weblogs - ICWSM 2007

From Tags to Ontology (5/5)
1) Create and tag post
2) Link tag to ontology
3) Link post to ontology
4) Create new post
5) Infer related post
21 October 24, 2009 Using Ontologies To Strenghten Folksonomies and Enrich Information Retrieval in Weblogs - ICWSM 2007

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

5
Enhanced Information Retrieval
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A Semantic Search Engine
• Decentralized data: • Using tags / ontology links to:
• Ontologies • Deal with tags variations
• Blog posts w/ RDF description • Remove ambiguity
• A central 3store w/ SPARQL
24 October 24, 2009 Using Ontologies To Strenghten Folksonomies and Enrich Information Retrieval in Weblogs - ICWSM 2007

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

Using instances co-occurrence
• Basic approach:
– Posts sharing concepts
– Ontology to remove ambiguity
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Using instances types
• Suggesting instances of the same
class:
– Programming languages
– Energy companies
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Defining specific rules
• Rule(s) for each class
• Location / {sub|top}locations
• Company / companies working
in the same area
28 October 24, 2009 Using Ontologies To Strenghten Folksonomies and Enrich Information Retrieval in Weblogs - ICWSM 2007

Rule example
• RDF rule • Reformulated w/ SPARQL
{! SELECT ?post ?topic ?domain!
:x rdf:type sioc:post .! WHERE {!
:y rdf:type sioc:post .! <$uri> [!
:x sioc:topic :a .! rdf:type ptop:Agent ;!
:y sioc:topic :b .! company:expertiseIn ?
domain!
:a rdf:type ptop:Agent .!
] .!
:b rdf:type ptop:Agent .!
?post sioc:topic ?topic .!
:a company:expertiseIn :d .!
?topic [!
:b company:expertiseIn :d !
rdf:type ptop:Agent ;!
} => {!
company:expertiseIn ?
:x sioc:related_to :y ! domain!
} . ] !
}
29 October 24, 2009 Using Ontologies To Strenghten Folksonomies and Enrich Information Retrieval in Weblogs - ICWSM 2007

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

6
Conclusion
31 October 24, 2009 Using Ontologies To Strenghten Folksonomies and Enrich Information Retrieval in Weblogs - ICWSM 2007

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

Thank you !
33 October 24, 2009 Using Ontologies To Strenghten Folksonomies and Enrich Information Retrieval in Weblogs - ICWSM 2007