Habilitation Thesis

Peer-to-Peer systems represent one of the most dynamic and challenging research area of distributed computing. With theoretical grounds on multi-agent systems, P2P systems get closer to the practice, allowing large communities to automate collaboration and deliver various services at low costs and good quality. Agents are defined as computer systems capable of independent and autonomous action on behalf of their users or owners, figuring out what need to be done to satisfy the design objectives. The definition leads the research towards formal aspects of the intelligence, agent research community being interested on formalizing the interaction, modeling agent behaviors, devising intelligent algorithms and ap-proaching pro-activity. By contrast, in distributed computing a peer represents just another node with the same rank with others. Peers interaction is practically modeled using the basic client-server paradigm, a peer playing either the role of the client, either the role of the server, without the requirement that some master (central) peer to coordinate everything. P2P systems gained such popularity tha