2. Agenda
Digital Enterprise Research Institute www.deri.ie
Microblogging: current state and issues
Requirements to enhance microblogging
SMOB – Semantic MicroBLogging
An ontology stack for Social Semantic Web applications
Distributed hubs and communication protocols
Integration with the Linking Open Data (LOD) cloud
Browsing, discovering and querying
Integrated capabilities (end-user interface, SPARQL, maps)
External indexes and components
Future Work
Conclusion
3. Microblogging
Digital Enterprise Research Institute www.deri.ie
Short status update, generally < 140 chars
Real-time information management / Citizen-sensing
Popular on the Web (Twitter) and in the enterprise (Yammer)
4. Limits of current systems
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And of Web 2.0 systems in general
Walled-garden systems / Lack of portability
Data belongs to the service used to publish it
Lack of structure / semantics
– Recent work on OpenGraph and Twitter Annotations
« A Bill of Rights for Users of the Social Web »
Most research on microblogging focuses on
communication patterns and social behaviours
But what about engineering issues ?
5. Requirements
Digital Enterprise Research Institute www.deri.ie
Machine-readable metadata (R1)
Making microblogging systems more interoperable
Focus on microblog posts, content and authors
Distributed architecture and open data (R2)
Solving the walled garden and data portability issues
Letting users own and control their data
Data reuse and interlinking (R3)
Interlinking microblog posts with other initiatives
Reusing existing data to make more sense of microblogging
6. SMOB – Semantic MicrOBlogging
Digital Enterprise Research Institute www.deri.ie
Our proposal
A framework for open, distributed and semantic
microblogging
Based on state-of-the-art Semantic Web technologies (RDF(S)/
OWL, RDFa, SPARQL) and Linked Data principles to provide
the previous requirements
SMOB - http://smob.me:
Open-source framework (GPL)
Started mid-2008, completely re-designed end-2009
– Distributed architecture, LOD-integration, etc.
7. The Semantic Web and Linked Data
Digital Enterprise Research Institute www.deri.ie
Semantic Web
From documents to structured data
Annotations (RDF), ontologies (RDFS/OWL), queries (SPARQL)
Linked Data
A set of principles for publishing data on the Web
Linking Open Data project – interlinking datasets on the Web
using the LD principles
8. SMOB and our initial requirements
Digital Enterprise Research Institute www.deri.ie
Machine-readable metadata (R1)
An ontology stack for microblogging
Representation of posts in RDFa, SPARQL endpoint
Distributed architecture and open data (R2)
Distributed hubs spread over the Web
Interacting via HTTP + SPARQL/Update
Data reuse and interlinking (R3)
Interlinking microblog (and their posts) with other systems
Reusing existing data when available
9. Ontologies for microblogging (R1)
Digital Enterprise Research Institute www.deri.ie
Different needs
Users and Profiles (Personal information and Social Networks)
Presence (Geolocation, current activity, etc.)
Data (microblog containers and microblog posts)
Topics (#tags)
Our approach
Integrating and extending existing lightweight ontologies to
focus on modularity and reusability of components
Providing a complete ontology stack for Semantic
Microblogging, and more broadly for any Social Semantic
Web application
10. FOAF – People and Social Networks
Digital Enterprise Research Institute www.deri.ie
FOAF – Friend Of A Friend
http://foaf-project.org
An ontology to describe people and their relationships
Can be integrated with any other SW vocabularies
FOAF on the Web
hi5, LiveJournal, Drupal 7, etc. and exporters for popular
services
11. FOAF – Distributed user-profiles
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Ability to reuse existing profiles
Such as RDFa-enabled documents (e.g. Drupal 7)
No need to duplicate personal data
foaf:depiction in RDFa
http://apassant.net
http://example.org
12. SIOC – Profiles and data
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SIOC – Semantically-Interlinked Online Communities
http://sioc-project.org
Representing online communities and their content
W3C Member Submission
A types module for finer-grained content-types
13. SIOC – Profiles and data
Digital Enterprise Research Institute www.deri.ie
SIOC extensions
Current state of SIOC cannot caputure all the properties of
microblogging
New Classes
sioct:MicroBlog : Microblog container
sioct:MicroblogPost : Microblog post
New properties
sioc:follows : following / followers (directed graph model)
sioc:addressed_to : @reply patterns
14. OPO – Presence Information
Digital Enterprise Research Institute www.deri.ie
OPO – Online Presence Ontology
http://online-presence.net
Representing rich presence information using semantics
Geolocation, current activity (project, etc.) …
Integration with SIOC to map content to the one’s presence
15. MOAT – Semantic Tagging
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MOAT – Meaning Of A Tag
http://moat-project.org
A model to provide semantic tagging capabilities
Linking #tags to their meanings (defined as URIs)
Provides integration with the Linking Open Data cloud
Tag Ontology
tag:RestrictedTagging
rdf:type http://example.org/tag/
apple
tag:associatedTag
http://example.org/
tagging1
tag:taggedBy tag:taggedResource
moat:tagMeaning
http://example.org/ http://dbpedia.org/
moat:taggedWith resource/Apple_Inc.
post/1
foaf:maker dct:title
Nouvel iPhone rdf:type MOAT + DBpedia
http://apassant.net/alex/
disponible
sioct:BlogPost
FOAF
SIOC + DC
16. The SMOB Ontology Stack
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Integration of the previous components
Plus a smob:Hub class to represent user’s hubs
Can be reused in various Social Semantic Web contexts
Makes Social Web applications part of the LOD cloud
17. Representation
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Each microblog post is represented in RDF using the
aforementionned ontology stack
Dereferenceable URI for each post
Subset directly in XHTML pages using RDFa (/page)
Complete representation also available using Turtle (/data)
18. Distributed architecture (R2)
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Personal SMOB hubs spread all over the Web
No central server / no dependency to 3rd-party services
Ensure data ownership and privacy
Each hub simply requires LAMP settings (based on ARC2)
and provides a SPARQL endpoint
Can be used as read-write Twitter clients
Following / follower registration
Ability to get « remote followers », represented internally
(in both the follower and followee hub) in RDF
:user_a sioc:follows :user_b .!
19. Communication between hubs
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Replication / notification between peers
Broadcasting data to followers when new content is created
Using SPARQL/Update via HTTP POST (Checking access rights)
Simple HTTP POST to Twitter API
20. Integration with the LOD cloud (R3)
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Semantic tagging
URIs being suggested on runtime when typing #tags
Integration of microblogging within the LOD cloud
(Dbpedia lookup, Sindice)
Plug-in system to add new service (e.g. enterprise KB)
21. Geolocation
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Geolocation features
Run-time geolocation lookup using GeoNames.org
Modelled as part of the user’s presence
22. Interlinking benefits
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Benefits of LOD interlinking
Can re-use backgound knowledge when querying data
– E.g. Microblog posts about any city in Italy (will retrieve #Torino)
Microblog content becomes more discoverable
23. Browsing, discovering and querying
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End-user interface
Genuine microblogging interface, on top of RDF data
Map view
Geolocation capabilities provided thanks to GeoNames
Integration with Sindice
Third-party service for identifying SMOB hubs and content
SPARQL endpoint
Direct queries and pluggable components via HTTP
24. End-user interface
Digital Enterprise Research Institute www.deri.ie
Genuine microblogging interface
Generated using SPARQL queries
Integration of Twitter posts (also stored in RDF)
RDFa markup for each post and user
25. Map view
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Geolocation features
Benefits of the GeoNames lookup integration
Reusing coordinates provided by the GeoNames KB (in RDF)
26. Integration with Sindice
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Sindice – the Semantic Web index
http://sindice.com
SMOB hubs can ping Sindice when new content is created
Retrieving distributed SMOB data from a single entry point
Transversal SPARQL querying to discover microblog posts
27. SPARQL endpoint
Digital Enterprise Research Institute www.deri.ie
Each hub provides its own endpoint
Using SPARQL, no need to learn a new API
Direct queries sent via HTTP / answers as JSON/XML
Ability to plug-in external components (e.g. Explorator)
28. Future Work
Digital Enterprise Research Institute www.deri.ie
Scalability
PubSubHubbub integration (cf. recent work on sparqlPuSH)
Cache system for rendering SPARQL-based pages
Modelling
Full-RDFa / content-negociation
Interlinking and data generation
Nanosyntaxes (generating RDF data about updates’ content)
Uptake
Spread the word to enrich the number of SMOB hubs
deployed on the Web !
29. Conclusion
Digital Enterprise Research Institute www.deri.ie
Contributions
An Ontology stack for Social Semantic Web applications
A distributed architecture for microblogging
Integration of microblogging with the LOD cloud
Deployed in SMOB – http://smob.me
Take-home message
There are opportunities for a distributed Social Semantic Web
SMOB can be just a part of this ecosystem, it’s up to you !
Semantic Web and Linked Data provide straightworward
integration of other components following the same approach
30. Thank you !
Digital Enterprise Research Institute www.deri.ie
http://smob.me
GNU/GPL, runs on any LAMP environment
Regular new features and bugfixes, consider the SVN version
Main contact
http://apassant.net
alexandre.passant@deri.org
@terraces