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


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


Microblogging

  Short status update, generally < 140 chars   Real-time information management / Citizen-sensing

  Popular on the Web (Twitter) and in the enterprise (Yammer)


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 ?


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


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.


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


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


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


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


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


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


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


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


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


  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


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)


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 .!


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


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)


Geolocation

  Geolocation features   Run-time geolocation lookup using GeoNames.org

  Modelled as part of the user’s presence


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


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


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


Map view

  Geolocation features   Benefits of the GeoNames lookup integration

  Reusing coordinates provided by the GeoNames KB (in RDF)


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


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)


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 !


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


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

  [email protected]

  @terraces

rethinking microblogging: open distributed semantic

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