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Semwebbers, LODers, what PubSubHubbub can do for you (SemTech)

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  • 1. Digital Enterprise Research Institute www.deri.ie SemWebbers, LODers: What PubSubHubbub can do for you Alexandre Passant DERI, NUI GalwaySemTech 2011June 09 2011, San Francisco© Copyright 2010 Digital Enterprise Research Institute. All rights reserved.
  • 2. AgendaDigital Enterprise Research Institute www.deri.ie   Real-time Web and Semantics   Push vs Pull   PubSubHubbub (PuSH), SemWeb and Linked Data   sparqlPuSH   SMOB   Twarql   Q/A
  • 3. A *real-time* WebDigital Enterprise Research Institute www.deri.ie   Information is no longer static   The Social Web as an information stream (Twitter, 4sq, ...)   New trends in ubiquitous computing   Sensor data and the IoT –  Even the @towerbridge is Tweeting !   A new area for Citizen Sensing   Earthquake detection (WWW2010 paper)   Emergency management, reporting and monitoring (Mumbai attacks on Flickr, Twitter, etc.)   Opinion / trends mining (Box office prediction by HP labs) 3 of XYZ
  • 4. Semantics and the real-time WebDigital Enterprise Research Institute www.deri.ie   Combining social stream, sensors and social data   What’s happening right now, sport-wise, 25km around here ? –  Geonames, Twitter, Dbpedia, etc.   Who in my social network, whatever the website we’re connected through, is currently in my hometown –  FOAF, Geonames, etc.   Any humidity issues in our server rooms in the US –  Sensors, Geonames, Legacy Enterprise Data, etc.   New architectures are required   Enabling pro-active notification based on triggers   Defining semantic triggers ? Yes, with SPARQL ! 4 of XYZ
  • 5. Pull vs PushDigital Enterprise Research Institute www.deri.ie   Pull   Constant queries to various sources to get what’s new   Useless HTTP calls (API/RSS), risks of being banned (TOS), costs and maintenance Schema by M. Dabrowski, DERI 5 of XYZ
  • 6. Pull vs PushDigital Enterprise Research Institute www.deri.ie   Push   Websites let me know when they have something relevant   Wait. Receive. Consume Schema by M. Dabrowski, DERI 6 of XYZ
  • 7. PubSubHubbub (PuSH) at a glanceDigital Enterprise Research Institute www.deri.ie   Google’s approach to enable Push on the Web   http://code.google.com/p/pubsubhubbub   Based on Atom / RSS –  link rel=“hub” header for identifying Hub from a feed   Simple registration / notification approach –  Libraries available in various languages –  Open source code for PuSH hub   Broadcasting data through public hubs –  Use Google’s one, Superfeedr, or host your own (e.g. Enterprise distribution of content) 7 of XYZ
  • 8. PubSubHubbub, SemWeb and LOD ?Digital Enterprise Research Institute www.deri.ie   Registrations and notifications of structured data   Efficient broadcasting of structured content at Web scale   sparqlPuSH   Pro-active notifications of changes in RDF stores   Real-time monitoring using SPARQL and PuSH   SMOB   Distributed microblogging   Syncing hubs with PuSH and SPARQL 1.1 Update   Twarql   Twitter stream analysis 8 of XYZ
  • 9. sparqlPuSH at a glanceDigital Enterprise Research Institute www.deri.ie   sparqlPuSH   Combining SPARQL, SPARQL Update and PubSubHubbub for pro-active notifications of changes in RDF stores   Can be plugged on the top of any RDF store - http://code.google.com/p/sparqlpush/   Based on   SPARQL to register feeds based on query patterns   SPARQL 1.1 Update for triggers registration and detection   Atom and RSS to get feeds of related changes   PubSubHubbub for broadcasting changes 9 of XYZ
  • 10. A 2-steps approachDigital Enterprise Research Institute www.deri.ie   A two-steps approach   Query registration   Change notification   A sparqlPuSH endpoint   Plugged on top of any RDF store (implementation-agnostic)   Registration can be done remotely, through an HTTP request sent to the sparqlPuSH endpoing   Notification is triggered as soon as relevant data appears in the store, loaded with SPARQL Update through sparqlPuSH   Clients must understand the rel=“hub” link in the feed header, and interpret notification from PuSH hubs 10 of XYZ
  • 11. Query registrationDigital Enterprise Research Institute www.deri.ie 11 of XYZ
  • 12. Example of query registrationDigital Enterprise Research Institute www.deri.ie   Identifying changes on a particular object   Be notified when something happens to ex:FooBar   Using the Changeset vocabulary by Talis 12 of XYZ
  • 13. Query registrationDigital Enterprise Research Institute www.deri.ie 13 of XYZ
  • 14. Conventions in query registrationDigital Enterprise Research Institute www.deri.ie   Using conventions to get a well-formatted Atom / RSS feed   Easier to read in standard aggregators   Mandatory elements   ?uri - their URI of the element(s) to be retrieved   ?date - their creation / modification date   Can be used to retrieve named graphs if content itself is not dated   Optional elements   ?label - their label   ?author - their author 14 of XYZ
  • 15. Browsing available feedsDigital Enterprise Research Institute www.deri.ie   The sparqlPuSH UI   Lists available feeds, including timestamp of last update   Ability to create feeds from the interface 15 of XYZ
  • 16. NotificationDigital Enterprise Research Institute www.deri.ie 16 of XYZ
  • 17. Notification on data updateDigital Enterprise Research Institute www.deri.ie   SPARQL Update support   HTTP-Posting data to the sparqlPuSH endpoint –  Then loaded in the underlying RDF store –  Allows *real-time* identification (as opposed to cron-job)   Identifying relevant changes   Applying all registered queries to the updated dataset   Broadcasting changes   Using PubSubHubbub ! (Scalability and RT delivery) 17 of XYZ
  • 18. ImplementationDigital Enterprise Research Institute www.deri.ie   Source code (PHP)   http://code.google.com/p/sparqlpush/ (BSD license)   Server   Connection to any SPARQL endpoint   Additional connector for ARC2 using the ARC2 API   Generating RSS or Atom feeds   Demo client   Registering / unregistering queries to remote interfaces   Receiving updates from registered feeds 18 of XYZ
  • 19. SMOBDigital Enterprise Research Institute www.deri.ie   Distributed and Semantic Microblogging   Setup your own hub, own your data, broadcast it   Fully SemWeb based (RDF backend, RDFa, LOD, etc.)   http://smob.me Local SPARQL/Update   SMOB and PuSH ?   Broadcasting SPARQL 1.1 Update queries (in RSS feed) SMOB hub at http://apassant.net HTTP POST   Instant notification for your SPARQL/Update + HTTP POST followers http://twitter.com   Ability to broadcast content deletion SMOB hub at http://example.org 19 of XYZ
  • 20. SPARQL 1.1 Update + RSS + PuSHDigital Enterprise Research Institute www.deri.ie 20 of XYZ
  • 21. TwarqlDigital Enterprise Research Institute www.deri.ie   Twitter feeds through SPARQL   Entity extraction from Twitter feeds   Representation as Linked Data (SMOB Stack)   SPARQL queries + PuSH for notifications   Code and demos   http://wiki.knoesis.org/index.php/Twarql   http://bit.ly/twarql 21 of XYZ
  • 22. Questions ?Digital Enterprise Research Institute www.deri.ie   Acknowledgements   Google Research Awards   Julie Anaya (SMOB + PuSH)   Pablo Mendes / Pavan Kapanipathi (Twarql)   Contact   alexandre.passant@deri.org   http://apassant.net   @terraces 22 of XYZ