Rethinking Microblogging: Open Distributed Semantic
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Transcript of Rethinking Microblogging: Open Distributed Semantic
© Copyright 2009 Digital Enterprise Research Institute. All rights reserved.
Digital Enterprise Research Institute www.deri.ie
Rethinking Microblogging: Open, Distributed, Semantic
Alexandre Passant, John G. Breslin, Stefan Decker
Digital Enterprise Research Institute, NUI Galway http://deri.ie
ICWE2010 Thursday, 8th July 2010 Vienna, Austria
Digital Enterprise Research Institute www.deri.ie
Agenda
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
Digital Enterprise Research Institute www.deri.ie
Microblogging
Short status update, generally < 140 chars Real-time information management / Citizen-sensing
Popular on the Web (Twitter) and in the enterprise (Yammer)
Digital Enterprise Research Institute www.deri.ie
Limits of current systems
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 ?
Digital Enterprise Research Institute www.deri.ie
Requirements
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
Digital Enterprise Research Institute www.deri.ie
SMOB – Semantic MicrOBlogging
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.
Digital Enterprise Research Institute www.deri.ie
The Semantic Web and Linked Data
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
Digital Enterprise Research Institute www.deri.ie
SMOB and our initial requirements
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
Digital Enterprise Research Institute www.deri.ie
Ontologies for microblogging (R1)
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
Digital Enterprise Research Institute www.deri.ie
FOAF – People and Social Networks
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
Digital Enterprise Research Institute www.deri.ie
FOAF – Distributed user-profiles
Ability to reuse existing profiles Such as RDFa-enabled documents (e.g. Drupal 7)
No need to duplicate personal data
http://apassant.net
http://example.org
foaf:depiction in RDFa
Digital Enterprise Research Institute www.deri.ie
SIOC – Profiles and data
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
Digital Enterprise Research Institute www.deri.ie
SIOC – Profiles and data
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
Digital Enterprise Research Institute www.deri.ie
OPO – Presence Information
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
Digital Enterprise Research Institute www.deri.ie
MOAT – Semantic Tagging
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
http://example.org/tagging1
http://apassant.net/alex/
http://example.org/tag/apple
http://example.org/post/1
tag:taggedResource
tag:associatedTag
tag:taggedBy
http://dbpedia.org/resource/Apple_Inc.
moat:tagMeaning
moat:taggedWith
sioct:BlogPost
Nouvel iPhone disponible
dct:title
rdf:type
foaf:maker
tag:RestrictedTagging
rdf:type
Tag Ontology
MOAT + DBpedia
SIOC + DC
FOAF
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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
The SMOB Ontology Stack
Digital Enterprise Research Institute www.deri.ie
Representation
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)
Digital Enterprise Research Institute www.deri.ie
Distributed architecture (R2)
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 .!
Digital Enterprise Research Institute www.deri.ie
Communication between hubs
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
Digital Enterprise Research Institute www.deri.ie
Integration with the LOD cloud (R3)
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)
Digital Enterprise Research Institute www.deri.ie
Geolocation
Geolocation features Run-time geolocation lookup using GeoNames.org
Modelled as part of the user’s presence
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Interlinking benefits
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
Digital Enterprise Research Institute www.deri.ie
Browsing, discovering and querying
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
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End-user interface
Genuine microblogging interface Generated using SPARQL queries
Integration of Twitter posts (also stored in RDF)
RDFa markup for each post and user
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Map view
Geolocation features Benefits of the GeoNames lookup integration
Reusing coordinates provided by the GeoNames KB (in RDF)
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Integration with Sindice
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
Digital Enterprise Research Institute www.deri.ie
SPARQL endpoint
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)
Digital Enterprise Research Institute www.deri.ie
Future Work
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 !
Digital Enterprise Research Institute www.deri.ie
Conclusion
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
Digital Enterprise Research Institute www.deri.ie
Thank you !
http://smob.me GNU/GPL, runs on any LAMP environment
Regular new features and bugfixes, consider the SVN version
Main contact http://apassant.net
@terraces