Enabling Networked Knowledge

Digital Enterprise Research Institute

Funded by Science Foundation Ireland under Grant No. SFI/08/CE/I1380 (Lion 2), IRC-SET scholarship, Google Research Award.

SemPuSH in SMOB

SMOB now uses Semantic Hub to provide its users a privacy-aware (controlled) content dissemination. A SMOB user generates preferences (SPARQL Query) based on hashtags he/she uses. SMOB automatically includes the preference with the content as and when a micropost containing the hashtag is generated.

Semantic Hub executes the preference on the publisher’s social graph. The subset of the subscribers retried are pushed with the appropriate content.

SemPush: Privacy-Aware and Scalable Broadcasting for Semantic Microblogging

Pavan Kapanipathi, Julia Anaya, Alexandre Passant

PubSubHubbub PubSubHubbub (PuSH) is a simple,

open, server to sever, web hook based communication protocol that is an extension to Atom and RSS.

SMOB -- Decentralized real-time architecture

SMOB is a Semantic Microblogging Frameworks. SMOB hubs are spread on the Web, owned and managed by users.

Hubs publish messages and/or subscribe to other hub feeds using PubSubHubBub (PuSH).

In addition, SMOB can also run on mobile or laptops thanks to Web Sockets.

Semantic Social Graph Semantic Hub stores the FOAF profiles of the users (pub/sub) during their first interaction with the Semantic Hub. The FOAF of the users are linked using the push vocabulary.

The push vocabulary is a light weight vocabulary used to model information of users communicating via the Semantic Hub.

Privacy Preference The publisher uses the light weight vocabulary PPO to define his/her privacy preferences.

The following example shows how a publisher, using PPO, can restrict a microblog post to users that are interested in the same concept used to tag the post.

<http://www.example.org/pp3> a ppo:PrivacyPreference; ppo:appliesToResource <http://smob.me/user/xyz/post1>; ppo:assignAccess acl:Read ppo:hasCondition [ ppo:hasProperty tag:Tag; ppo:resourceAsObject

<http://dbpedia.org/resource/Linked_Data> ]; ppo:hasAccessSpace [ ppo:hasAccessQuery "ASK { ?x foaf:topic_interest <http://dbpedia.org/resource/Linked_Data> }" ].

Want to learn more ? Check the project website and get SMOB source code (GNU/GPL) at http://smob.me

Full-paper describing the SMOB architecture at ICWE2010

Publisher Subscriber Hub

1. I have new content for feed X

2. Give me the latest content

for feed X

3. Here it is

Subscriber Subscriber Subscriber Subscriber

4. Here is the latest content

for feed X

Push Updates

1

SemPuSH – Protocol Extension Publisher during the update of new

content, also provides its preference on who should receive the content to the Semantic Hub.

As in PuSH, the complexity of user-controlled dissemination is at the Hub. Semantic Hub stores the profiles of the users as a publisher centric social graph, thatis used to fetch the list of subscribers eligible to receive the content.

Publisher

Sub - A

Sub - B

Sub - C

Sub - D

1. Hey I have new content for

feed X + my preference Y

Social Graph

4. Get the subscribers of Pub

whose profile matches preference

Y

2. Give me the new content

3. Here it is

Semantic Hub

Kno.e.sis Ohio Center Of Excellence

SMOB – B Interest: Knowledge Engg

Semantic Hub

Social Graph

1. POST “Presentation at ISWC by me on

Sunday #semanticweb”

2. Get my privacy settings for

dbPedia:Semantic_Web

3. Access Space: #semanticweb SELECT ?user WHERE {

?user foaf:topic_interest ?topic ?topic dcterms:subject category:Semantic_Web }

5. Get micropost+ Access Space

4. There is a micropost

6. Get subscribers matching

Access Space

7. SMOB – B And

SMOB - D

8. Push Updates

What is missing?

PubSubHubbub used for Distributed Social Networks such as SMOB does not allow publisher controlled dissemination of content, i.e. the content is broadcasted to all the subscribers for the corresponding publisher.

SMOB – C Interest: Computer Networks

SMOB – D Interest: Semantic Search

SMOB – A RDF

http://smob.me http://semantichub.appspot.com

Kapanipathi Pavan, Anaya Julia, Sheth Amit, Slatkin Brett, and Passant Alexandre. Privacy-Aware and Scalable Content Dissemination in Distributed Social Networks. In Proceedings of the 10th International Semantic Web Conference,ISWC’11, 2010.

5. Here is the latest content

for feed X