The document discusses the SMOB framework, a decentralized semantic microblogging architecture that allows users to manage privacy-aware content dissemination using the PubSubHubbub protocol. It explains how publishers can control who receives their updates based on user preferences and social graphs, facilitating targeted content delivery. The work, which is funded by various organizations, emphasizes user-centric privacy within distributed social networks.

1. Digital Enterprise Research Institute
Kno.e.sis Ohio Center Of Excellence
Push Updates
SemPush: Privacy-Aware and Scalable
Broadcasting for Semantic Microblogging
1
Pavan Kapanipathi, Julia Anaya, Alexandre Passant
SMOB -- Decentralized realtime architecture
SMOB is a Semantic Microblogging
Frameworks. SMOB hubs are spread on
the Web, owned and managed by
users.
PubSubHubbub
SemPuSH – Protocol Extension
PubSubHubbub (PuSH) is a simple,
open, server to sever, web hook based
communication protocol that is an
extension to Atom and RSS.
Publisher during the update of new
content, also provides its preference on
who should receive the content to the
Semantic Hub.
1. I have
new content
for feed X
Hubs publish messages and/or
subscribe to other hub feeds using
PubSubHubBub (PuSH).
2. Give me
the new
content
1. Hey I have
new content for
feed X + my
preference Y
4. Here is the
latest content
for feed X
Sub - A
Sub - B
Publisher
Hub
Subscriber
Subscriber
Subscriber
Subscriber
Semantic Hub
Publisher
Sub - C
Subscriber
3. Here it
is
4. Get the
subscribers of Pub
whose profile
matches preference
Y
What is missing?
In addition, SMOB can also run on
mobile or laptops thanks to Web
Sockets.
http://smob.me
<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> }"
].
http://semantichub.appspot.com
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.
1. POST
2. Get my privacy settings for
dbPedia:Semantic_Web
Privacy Preference
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.
Social
Graph
SemPuSH in SMOB
Semantic Social Graph
The publisher uses the light weight
vocabulary PPO to define his/her privacy
preferences.
5. Here is the
latest content
for feed X
As in PuSH, the complexity of usercontrolled 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.
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.
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.
Sub - D
3. Here
it is
2. Give me the
latest content
for feed X
“Presentation at
ISWC by me on
Sunday
#semanticweb”
6. Get subscribers
matching
Access Space
Social
Graph
7. SMOB – B
And
SMOB - D
4. There is a micropost
RDF
SMOB – A
5. Get micropost+
Access Space
Semantic Hub
3. Access Space: #semanticweb
SELECT ?user WHERE {
?user foaf:topic_interest ?topic
?topic dcterms:subject category:Semantic_Web }
8. Push
Updates
SMOB – B
SMOB – C
SMOB – D
Interest: Knowledge Engg
Interest: Computer Networks
Interest: Semantic Search
Semantic Hub executes the preference on the publisher’s social graph. The
subset of the subscribers retried are pushed with the appropriate content.
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.
Funded by Science Foundation Ireland under Grant No. SFI/08/CE/I1380 (Lion 2), IRC-SET scholarship, Google Research Award.
Enabling Networked Knowledge