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Privacy Aware Semantic Dissemination

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Centralized social networking websites raise scalability issues — due to the growing number of participants — and policy concerns — such as control, privacy and ownership of users’ data. Distributed Social Networks aim to solve those by enabling architectures where people own their data and share it whenever and to whomever they wish. However, the privacy and scalability challenges are still to be tackled. Here, we present a privacy-aware extension to Google’s PubSubHubbub protocol, using Semantic Web technologies, solving both the scalability and the privacy issues in Distributed Social Networks. We enhanced the tradi- tional features of PubSubHubbub in order to allow content publishers to decide whom they want to share their information with, using semantic and dynamic group-based definition. We also present the application of this extension to SMOB (our Semantic Microblogging framework). Yet, our proposal is application agnostic, and can be adopted by any system requiring scalable and privacy-aware content broadcasting.

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Privacy Aware Semantic Dissemination

  1. 1. Privacy-Aware and Scalable ContentDissemination in Distributed Social Networks Pavan Kapanipathi 1,2, Julia Anaya 1, Amit Sheth 2, Brett Slatkin 3, Alexandre Passant 1 1 Digital Enterprise Research Institute, Galway – Ireland 2 Kno.e.sis, Dayton, OH- USA 3 Google, San Fransisco, CA - USA 1
  2. 2. Agenda• Background• Motivation• Semantic Hub – Protocol• SMOB + Semantic Hub• Conclusion• Future Work 2
  3. 3. Social Networks• Centralized Social Networks (CSN)s • Twitter and Facebook.• What’s missing? • Users don’t own their data • Consistent privacy and performance concerns• Distributed Social Networks • Diaspora, SMOB, StatusNet, OneSocialWeb 3
  4. 4. Distributed Social Networks• Users own their data • Own Social Space • Decentralized servers• Better Performance• Google’s PubSubHubbub protocol • Communication protocol used in most Distributed Social Networks • Improves scalability • Near-instant notifications 4
  5. 5. • PubSubHubbub – Communication protocol • Simple, Open, web-hook based pubsub protocol • Extension to RSS, Atom. Give me your latest content for feed X, please Publisher Subscriber 5 I have delegated distribution task to a Hub
  6. 6. • PubSubHubbub – Communication protocol • Simple, Open, web-hook based pubsub protocol • Extension to RSS, Atom. I want to subscribe to feed X Publisher Hub Subscriber 6 Hey Did Yup, its really u send me not a DoS this?? attacker.
  7. 7. • PubSubHubbub – Communication protocol • Simple, Open, web-hook based pubsub protocol • Extension to RSS, Atom. I have new Here is the content for latest content feed X for feed X Publisher Hub Subscriber Subscriber Subscriber Subscriber 7 Subscriber Give me the Here it is latest content 7 for feed X
  8. 8. Motivation – Privacy • Twitter – Data is either • Private – authorized followers • Public – Everyone (No authorization required to follow) “Cisco just offered me a job! Now I have to weigh the utility of a fatty paycheck against the daily commute to San Jose and hating the work.” 8http://www.msnbc.msn.com/id/29796962/ns/technology_and_science-tech_and_gadgets/t/twitter-gets-you-fired-characters-or-less/
  9. 9. Motivation• Micropost -- “good presentation about Linked Data: then, now and next http://bit.ly/xyz”• Decide on your audience • Almost certain about getting the message across to the right audience 9
  10. 10. Protocol – Extension(Overview)• Publishers’ Preferences • Content also includes its preferences (recipients)• Complexity at the Hub • Store Social Graph of the Publisher • Filter appropriate Subscribers to push the content 10
  11. 11. PubSubHubbub ProtocolExtensionHey I have new Here is the Give me new contentcontent for feed the new X + my of feed X content Follower - A preference Y Follower - B Pub Semantic Hub Follower - C Here it Follower - D is Get the subscribers Social of Pub whose profile Graph matches preference Y 11
  12. 12. Protocol In-Use• SMOB • Privacy-Aware Microblog dissemination• Personalized Filtering • Twitter Stream (SPIM Workshop) 12
  13. 13. SMOB + Semantic Hub• Open and Distributed Semantic Microblogging Framework • http://smob.me• PuSH implementation used to broadcast content • Privacy was a concern• Our Privacy-Aware protocol implementation used • http://semantichub.appspot.com 13
  14. 14. POST RDF “Presentation at ISWC by me on Get subscribers SMOB – B Get my privacy settings for Sunday matching And dbPedia:Semantic_Web #semanticweb” Access Space SMOB - D There is a micropost SMOB – A RDF Interest: Sematic Web Get micropost+ Semantic Hub Access Space Access Space: #semanticweb SELECT ?user WHERE { ?user foaf:topic_interest ?topic?topic dcterms:subject category:Semantic_Web Push Updates SMOB – B SMOB – C SMOB – D Interest: Knowledge Engg Interest: Computer Networks Interest: Sematic Search 14
  15. 15. POST RDF “Presentation at ISWC by me on Get subscribers SMOB – B Get my privacy settings for Sunday matching And dbPedia:Semantic_Web #semanticweb” Access Space SMOB - D There is a micropost SMOB – A RDF Interest: Sematic Web Get micropost+ Semantic Hub Access Space Access Space: #semanticweb SELECT ?user WHERE { ?user foaf:topic_interest ?topic?topic dcterms:subject category:Semantic_Web Push Updates SMOB – B SMOB – C SMOB – D Interest: Knowledge Engg Interest: Computer Networks Interest: Sematic Search 15
  16. 16. Publisher – Privacy Preferences • Feature based preferences at Publisher • Content generated for topic Linked Data • Micropost containing hashtag #knoesis • Modeled using Privacy Preference Ontology (PPO) • Fine grained restrictions • SPARQL Queries representing the subset of subscribers from the Social Graph in the hub 16Privacy Preference Ontology – Work by Owen Sacco, Alexandre Passant DERI
  17. 17. Privacy Preference Ontology (PPO)• Publishing Data on Web as a part of Linked Open Data has privacy issues. • Web Access Control ontology (WAC)• PPO -- Light weight vocabulary • On top of Web Access Control Ontology • Fine grained privacy preferences for RDF Data • Example: Share email, phone number in my FOAF profile to Users with workplace as Kno.e.sis Center. 17
  18. 18. Privacy Preferences using PPOExample: Restrict all the documents tagged with Semanticweb to only those users who are interested in SemanticWeb<http://example.org/privacy/3> a ppo:PrivacyPreference; ppo : appliesToResource <http://xmlns.com/foaf /0.1/Document>; ppo : hasCondition [ ppo : hasProperty tag:Tag; ppo : resourceAsObject dbpedia : Semantic Web ]; ppo: assignAccess acl :Read; ppo : hasAccessSpace [ ppo:hasAccessQuery ”SELECT ?user WHERE { 18 ?user foaf : topic interest dbpedia:Semantic Web }” ].
  19. 19. SMOB’s Simple Interface – PrivacyPreference Generation 19
  20. 20. POST RDF “Presentation at ISWC by me on Get subscribers SMOB – B Get my privacy settings for Sunday matching And dbPedia:Semantic_Web #semanticweb” Access Space SMOB - D There is a micropost SMOB – A RDF Interest: Sematic Web Get micropost+ Semantic Hub Access Space Access Space: #semanticweb SELECT ?user WHERE { ?user foaf:topic_interest ?topic?topic dcterms:subject category:Semantic_Web Push Updates SMOB – B SMOB – C SMOB – D Interest: Knowledge Engg Interest: Computer Networks Interest: Sematic Search 20
  21. 21. Semantic Hub – Distributed SocialSemantic Graph• FOAF Profiles of Publishers/Subscibers• Semantic Social Graph at the Semantic Hub • FOAF profiles linked using push vocabulary• Distributed • Every user owns a Hub 21
  22. 22. FOAF -- Exchange Hey, I want to Great, Since it is Publish/Subscribe your first time. I Content of feed X need your profile Pub/Sub Semantic Hub OK, Let me confirm ur identity Profile stored Social 22 Here is my Graph profile
  23. 23. Push Vocabulary• SIOC vocabulary • Models information from online communities • Communication protocols are not considered• PubSubHubbub Vocabulary (push) • Models information of users communicating via Semantic Hub 23
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  25. 25. POST RDF “Presentation at ISWC by me on Get subscribers SMOB – B Get my privacy settings for Sunday matching And dbPedia:Semantic_Web #semanticweb” Access Space SMOB - D There is a micropost SMOB – A RDF Interest: Sematic Web Get micropost+ Semantic Hub Access Space Access Space: #semanticweb SELECT ?user WHERE { ?user foaf:topic_interest ?topic?topic dcterms:subject category:Semantic_Web Push Updates SMOB – B SMOB – C SMOB – D Interest: Knowledge Engg Interest: Computer Networks Interest: Sematic Search 25
  26. 26. Semantic Hub – ContentDistribution• RSS Extension • Element to include the privacy preference • privacy, accessspace• Each updated content is received by restricted subscribers • Privacy Preference for each content fetches the matched subscribers • Preferences are deleted before distribution 26
  27. 27. RSS Extension<item> <title>Only Friends</title> <description> Send this to only people I know and interested in SemanticWeb </description> <link>http://example.org /rss</link> <guid>123123123123</guid> <pubDate>March 06 2001</pubDate> <privacy> <accessspace> SELECT ?user WHERE { foaf :me foaf :knows ?user . ?user foaf : topic interest dbpedia:Semantic Web.} </accessspace> … 27 </privacy></item>
  28. 28. Personalized Filtering of theTwitter Stream• Profile Generator • Automatic generation of User Profiles• Semantic Filter • Annotating Twitter Stream with concepts from Linked Open Data• Semantic Hub • Delivering tweets to appropriate Interested Users (near real-time) 28
  29. 29. Architecture Annotate: iPhone Get ?user foaf:interest Subscribers The new based on dbPedia:iPhoneiPhone has a 3.5- preference Union inch screen, ?user foaf:interest released today Category:Apple Get Interested Subscribers RDF Semantic Filter Notify Update A N RDF N Store and O T Query Topics Semantic Hub A Fetch Updates T O RSS Store FOAF R Update RSS Profile Generator Push Updates to Interested Users 29 Create Profile
  30. 30. Conclusion• Extension of Google’s PuSH protocol to cope with privacy concerns.• Implementation of the protocol• Use in SMOB (Microblogging)• Push vocabulary to model activities via PuSH protocol 30
  31. 31. Future Work• Enabling the architecture for mobile devices.• Communicate to and from devices that are offline and still need to be notified. 31
  32. 32. Thanks Acknowledgements: Fabrizio Orlandi Owen Sacco Contact us: {pavan, amit}@knoesis.org {alexandre.passant, julia.anaya}@deri.org brettslatkin@google.com 32This work is funded by (1) Science Foundation Ireland under grant number SFI/08/CE/I1380 (Lıon 2) and by anIRCSET scholarship supported by Cisco Systems (2) Social Media Enhanced Organizational Sensemaking inEmergency Response, National Science Foundation under award IIS-1111182, 09/01/2011 - 08/31/2014.
  33. 33. PubSubHubbub• PuSH is a scalable protocol, and Google provides a public hub that people can use to broadcast their content.• This public hub delivers for approximately 40 million unique active feeds• 117 million subscriptions.• In two years, approximately 5.5 billion unique feeds have been delivered• fetching 200 to 400 feeds• delivering 400 to 600 of them per second.• Its largest subscribers get between 20 and 120 updates per second from the hub. 33
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