COPS10 Workshop Report
From P2P Wiki
Pedro García López
Departament d'Enginyeria Informàtica i Matemàtiques University Rovira i Virgili, Spain pedro.garcia@urv.cat
Contents |
Introduction
The COPS workshop aims to gather innovative researchers to discuss about hot topics in peer-to-peer systems. Despite its relative youth, peer-to-peer has atracted a major audience in the last years, with major contributions in decentralized topologies, content distribution networks and collaborative infrastructures. In fact, recent contributions in the field are enabling masssively scalable systems with millions of users. To name a few, we can outline Bittorrent (generating huge amounts of traffic in the Internet), Skype (Voice over IP) or Spotify (Music distribution) among many others. Furthermore, advances in the field are being used now in scalable cloud infrastructures like Amazon's Dynamo or Google App Engine.
The Sixth International Workshop on Collaborative Peer-to-Peer Systems has attracted high quality submissions from top research groups around the world. It received 15 submissions from 12 countries and it is creating a vibrant community of researchers in the peer-to-peer topic. After the review process, 6 full papers were included in the final program.
The high quality submissions have demonstrated the relevance of the topic and the recent trends in the peer-to-peer research community. The workshop was divided in two sessions: social networks and p2p middleware. Researchers from top research groups in peer-to-peer systems presented their novel contributions in this vibrant topic.
Social Networks
David Wolinsky, Pierre St Juste, Oscar Boykin and Renato Figueiredo present a paper entitled "OverSoc: Social Profile Based Overlays". Authors present a novel approach to constructing completely decentralized social networks through P2P overlays. Their approach relies on a directory overlay, which enables friend discovery and bootstraps connectivity to individualized profile overlays. The overall system is secured using PKI infrastructures.
Rammohan Narendula, Thanasis Papaioannou and Karl Aberer present a paper entitled "Privacy-aware and highly available OSN profiles". Authors present a privacy-aware decentralized OSN called Porkut. Their system exploits trust relationships in the social network for decentralized storage of OSN profiles and their content. By taking users' geographical locations and online time statistics into account, it also addresses availability and storage performance issues. Finally, they propose an approach for indexing in a privacy-preserving manner in decentralized social networks.
Róbert Ormándi, István Hegedűs, Kornél Csernai and Márk Jelasity present a paper entitled "Towards inferring ratings from user behavior in BitTorrent communities". They address the important topic of content recommendations in peer-to-peer communities. They present their work with a large trace of Filelist.org, a BitTorrent-based private community, and demonstrate that they can identify a binary like/dislike distinction over the set of files users are downloading, using dynamic features of swarm membership.
P2P Middleware
Andrei Vancea and Burkhard Stiller present a paper entitled "CoopSC: A Cooperative Database Caching Architecture". They present the CoopSC system, a cooperative database caching architecture, which extends the classic semantic caching approach by allowing clients to share their local caches in a cooperative matter. Cache entries of all clients are indexed in a distributed data structure constructed on top of a Peer-to-Peer (P2P) overlay network. They claim that their approach decreases the response time of database queries and the amount of data sent by database server, because the server only answers those parts of queries that are not available in the cooperative cache.
Boris Mejias, John Thomson, Paulo Trezentos, Gustavo Gutierrez and Peter Van Roy present a paper entitled "Lock-Free Decentralized Storage for Transactional Upgrade Rollback". They present a novel DHT functionality that enables Transactional Upgrade Rollback in decentralized software distribution environments. They reduce the total amount of storage by having a decentralized architecture using a Distributed Hash Tree (DHT) to localise shared resources. To this end, they propose a generic lock-free key/value-set protocol to add and remove data from the DHT.
Daniel Lázaro Iglesias, Joan Manuel Marquès and Xavier Vilajosana present a paper entitled "Flexible resource discovery for decentralized P2P and volunteer computing systems". Authors address the topic of resource discovery mechanisms in volunteer peer-to-peer computing networks. They present a decentralized resource discovery mechanism that provides constant look-up latency for frequent resources in the average case, while causing a low overhead and tolerating the levels of churn that are to be expected from non-dedicated resources.
Conclusions
The COPS workshop is consolidating a strong community of top researchers around the hot topic of Peer-to-Peer Systems. Peer-to-peer is transversal to many disciplines like Grid systems, Cloud computing, pervasive environments, and social networks. In this line, peer-to-Peer features like decentralization, self-management, or scalability make this field very important for the Internet of the Future.
The COPS10 best paper was awarded to "Towards inferring ratings from user behavior in BitTorrent communities". This article obtained the best ratings from reviewers who considered this work important and pioneer in peer-to-peer recommendations. It is very positive that they publish in the Web the resulting database containing the inferred ratings. This database could be used as a benchmark for P2P recommender systems.
