1 Whats Up: P2P news recommender Anne-Marie Kermarrec Joint work with Antoine Boutet, Davide Frey (INRIA) and Rachid Guerraoui (EPFL) Gossple workshop 2010

2 The social Web Web content is generated by you, me, your friends and millions of others The Web has turned social

Content comes from everywhere Gossple workshop 20103

Is it equally relevant? Gossple workshop 20104

Is it equally relevant? Gossple workshop 20105

Is it equally relevant? Gossple workshop 20106

Whats wrong with news feed? Amazon recommends me a fryer Some of my Facebook write in Italian LeMonde.fr wants to inform me on the Champions ligue Gossple workshop 20107

Why is it so difficult? Even a space restricted to users explicit subscriptions is too large a database Dynamic Recommendations not always user-centric Explicit links not always that relevant Classical pub/sub do not filter enough Granularity of a user seems too coarse Gossple workshop 20108

Cascading over explicit links Gossple workshop 20109

Fine grain tuning calls for decentralisation Gossple workshop

Whats up Decentralised information dissemination channel Simple interface: I like it or I dont Exploit implicit social links Gossple workshop

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Whats up in a nutshell Gossple workshop

Whats up challenges Gossple workshop Who are my social acquaintances How to discover them? How to disseminate news ? Similarity metric Through gossip Biased epidemic protocol

Whats up: Gossple net Gossple workshop

Whats up challenges Gossple workshop Who are my social acquaintances How to discover them? How to disseminate news ? Similarity metric

An implicit social network Gossple workshop

Which nodes should be considered as social acquaintances? Model U(sers) × I(tems) (news) Profile(u) = vector of liked news Minimal information Similarity metrics Overlap Cosine similarity Multi-interest similarity Gossple workshop

Item cosine similarity 19Gossple workshop 2010 Normalized overlap Profile(u)= Vector of news Items{u}

Individual rating might be too restrictive Rate the set of users instead of individuals 20 Items of interest for nodes in set(n) Items of interest for nodes in set(n) Distribution Normalized not to take into account non shared interests Normalized not to take into account non shared interests Gossple workshop 2010

Whats up challenges Gossple workshop Who are my social acquaintances How to discover them? How to disseminate news ? Through gossip

22 The Gossple network Gossple workshop 2010 Copyright: E. Rivière Gossip similarity protocol. Gossip-based peer sampling service

Gossple social network Gossple workshop port :2110 Bloom Filter Update :2020 Profile Update time5 Friends Uniform sample c entries k entries

Gossple workshop Building the social network Two gossip protocols Similarity-based Peer Sampling Random Peer Sampling When p encounters q Evaluate potential new view, based on set similarity metric Use of Bloom filters to limit the communication overhead RPS SPS RPS SPS

Whats up in a nutshell Gossple workshop

Whats up challenges Gossple workshop Who are my social acquaintances How to discover them? How to disseminate news ? Biased epidemic protocol

Dissemination Gossple workshop Heterogeneous Homogeneous HeterogeneousHomogeneous Involvement (fanout) Expectations Epidemic Dissemination F=log(N) Heterogeneous Gossip F log(N) on average

BEEP: orientation and amplification Orientation: to whom? Gossple workshop Forward to friends Forward to random Amplification: to how many? Increase fanout Decrease fanout

Beep: I like it Gossple workshop I like it!

Beep: I dont Gossple workshop I dislike it!

Tuning BEEP Orientation The news carries the list of visited users A profile: sum of interests of users who liked it Amplification F log(N) friends Amplification depends on the similarity between the news and the user F 1 or 2 random Gossple workshop

Evaluation User Metrics Spam Recall Precision System metric Number of messages Redundancy (useless messages) Traces Synthetic clustered traces Real dataset: 700 Digg users/2000 news/1 week Gossple workshop

Preliminary results Gossple workshop AlgorithmPrecisionRecallSpam Perfect110 Gossip fanout=log(n)= Cascading through explicit friends from Digg WhatsUp fanout=11/1 ; ttl= WhatsUp without no social users

To take away Automatic light news recommender Analysis through mean field theory Experimental evaluation Next: diversity of sources, trust, privacy Gossple workshop

Thank you 35 Gossple workshop 2010

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