Applying information retrieval techniques in peer-to-peer infrastructures is a demanding challenge. Peer-to-peer systems are already being used for a vast number of applications in content exchange, but mostly searching is done by simple keyword lookups. In contrast, information Retrieval techniques vastly differ from retrieval in pure data management systems. Information retrieval means that n...

Finding information in a peer-to-peer system currently requires either a costly and vulnerable central index, or ooding the network with queries. In this paper we introduce the concept of Routing Indices (RIs), which allow nodes to forward queries to neighbors that are more likely to have answers. If a node cannot answer a query, it forwards the query to a subset of its neighbors, based on its ...

In Peer-to-Peer data sharing systems, peers typically play equal roles and have equal capabilities. From the service perspective, peers provide a single service. For this reason, there is no need to explicitly model services. We argue, that for knowledge sharing systems, we need an effective combination of the capabilities of the peers both in terms of the services as well as the content they p...

Most of the existing research in peer-to-peer systems focuses on protocol design and doesn’t consider the rationality of each peer. One phenomenon that should not be ignored is free riding. Some peers simply consume system resources but contribute nothing to the system. In this paper we present an agentbased peer-to-peer system, in which each peer is a software agent and the agents cooperate to...

Introduction The second International Workshop on Collaborative Peer-to-Peer Information Systems, COPS06 was held in Manchester University as part of WETICE-2006. It was the second meeting devoted to the study of the emerging field of Cooperative Information Systems and P2P networks or Cooperative P2Pbased Information Systems (COPS). The first edition has been focused on trust management and mi...

We study distributed linearization or topological sorting in peer-to-peer networks. We define strict and eventual versions of the problem and consider these problems with and without input identifiers that do not exist in the system. None of these problems are solvable in the asynchronous messagepassing systems. We define a collection of oracles and prove which oracle combination is necessary t...

There are currently one billion mobile devices (e.g. phone, PDAs etc) worldwide, a figure which is rising rapidly. On the other side of the scale, predictions indicate there will be 490 million Internet users by the year-end 2002 and over 765 million by year-end 2005. Each user in this massive network has the CPU capability of more than 100 times that of an early 1990s supercomputer and surpris...

In live streaming systems (IPTV, life-stream services, etc.), an attractive service consists in allowing users to access past portions of the stream. This is called a time-shifted streaming system. In our vision, a centralized time-shifted streaming system face scalability and ethical issues, therefore, we address the problem of designing a peer-to-peer system where peers store and deliver past...

Recent development of peer-to-peer (P2P) services (e.g. streaming, file sharing, and storage) systems introduces a new type of queue systems not studied before. In these new systems, both job and server arrive and depart randomly. The server dynamics may or may not correlate to the job dynamics. Motivated by these observations, we develop queuing models for P2P service systems and a taxonomy fo...