Gianluca Moro

Agents and Peer-to-Peer Computing

Invited Paper.- Information Flow Analysis in Autonomous Agent and Peer-to-Peer Systems for Self-organizing Electronic Health Records.- P2P Infrastructure.- Hybrid DHT Design for Mobile Environments.- DANTE: A Self-adapting Peer-to-Peer System.- The Exclusion of Malicious Routing Peers in Structured P2P Systems.- Agents in P2P.- Cooperative CBR System for Peer Agent Committee Formation.- Mobile Agent-Based Approach for Resource Discovery in Peer-to-Peer Networks.- P2P Search.- Chora: Expert-Based P2P Web Search.- K-link: A Peer-to-Peer Solution for Organizational Knowledge Management.- An Analysis of Interest-Community Facilitated Peer-to-Peer Search.- Applications.- Mitigating the Impact of Liars by Reflecting Peers Credibility on P2P File Reputation Systems.- A Comparative Study of Reasoning Techniques for Service Selection.- PROSA: P2P Resource Organisation by Social Acquaintances.- Reliable P2P File Sharing Service.- Studying Viable Free Markets in Peer-to-Peer File Exchange Applications without Altruistic Agents.- Distributed Multi-layered Network Management for NEC Using Multi-Agent Systems.- Facilitating Collaboration in a Distributed Software Development Environment Using P2P Architecture.- A Peer to Peer Grid Computing System Based on Mobile Agents.

Agent-based distributed data mining: the KDEC scheme

One key aspect of exploiting the huge amount of autonomous and heterogeneous data sources in the Internet is not only how to retrieve, collect and integrate relevant information but to discover previously unknown, implicit and valuable knowledge. In recent years several approaches to distributed data mining and knowledge discovery have been developed, but only a few of them make use of intelligent agents. This paper is intended to argue for the potential added value of using agent technology in the domain of knowledge discovery. We briefly review and classify existing approaches to agent-based distributed data mining, propose a novel approach to distributed data clustering based on density estimation, and discuss issues of its agent-oriented implementation.

G-Grid: a class of scalable and self-organizing data structures for multi-dimensional querying and content routing in p2p networks

Peer-to-Peer (P2P) technologies promise to provide efficient distribution, sharing and management of resources, such as storage, processing, routing and other sundry service capabilities, over autonomous and heterogeneous peers. Yet, most current P2P systems only support rudimentary query and content routing over a single data attribute, such as the file-sharing applications popularized in Napster, Gnutella and so forth. Full-fledged applications in distributed data management and grid computing demand more complex functionality, including querying and content routing over multiple attributes. In this paper we present a class of scalable and self-organizing multi-dimensional distributed data structures able to efficiently perform range queries in totally decentralized dynamic P2P environments. These structures are not imposed a priori over the network of peers. Rather, they emerge from the independent interactions of autonomous peers. They are also adaptive to unanticipated changes in the network topology. This robustness property expands their range of usefulness to many application areas such as mobile ad-hoc networks.

Agents and peer-to-peer computing: a promising combination of paradigms

P2P personal information-sharing services will see explosive growth, reaching 35% of all online users by 2006. Once personal P2P applications are common and the infrastructure supports them, computing will change. Developers of Web-based applications will realize that adding P2P functionality makes their apps come alive -user communication is the secret sauce for enhancing client- server applications.

Issues of agent-based distributed data mining

Matthias Klusch Deduction and Multiagent Systems German Research Centre for Artificial Intelligence Stuhlsatzenhausweg 3 66123 Saarbruecken, Germany klusch@dfki.de Stefano Lodi Department of Electronics, Computer Science and Systems IEIIT-BO/CNR University of Bologna Viale Risorgimento 2 40136 Bologna BO, Italy slodi@deis.unibo.it Gianluca Moro Department of Electronics, Computer Science and Systems University of Bologna Via Rasi e Spinelli 176 47023 Cesena FC, Italy gmoro@deis.unibo.it

Identification of communities of peers by trust and reputation

We present a new model and a partial solution to the problem of semantic routing in peer-to-peer networks. When a peer receives a query, an attempt to solve the query by using both linguistic and contextual knowledge is made. In our proposal, each peer analyzes the result of its queries and increases the trust of those peers who reply with more appropriate semantic contents. In this respect, our approach is adaptive. As queries are resolved, the routing strategy of each peer becomes more and more trust-based, namely, based on the semantics of contents rather than on a mere syntactic matching of keywords. This leads to the emergence of communities of peers semantically related, which in turn corresponds to a peer-to-peer network clustered by contents, capable to resolve queries with a reduced number of hops.

On observation as a coordination paradigm: an ontology and a formal framework

observation pattern represents one of the most common and widespread coordination schemata in today complex models and systems, as it emerges from a variety of different research and ap- plication areas. This paper aims first at providing a common onto- logical foundation for the many different models, architectures, and systems supporting the observation pattern, allowing them to be classified and compared despite their seeming diversity. Based on such an ontology, this paper introduces then a coordination frame- work to formally model the observable behaviour (manifestation) of a knowledge source, as well as its interaction with observers. The expressiveness and effectiveness of both the ontology and the coordination framework are put to test by expressing manifestation and observation as they occur within both well-known coordination models and different paradigms like object-oriented languages, ac- tive databases, and agent systems.

W-Grid: a Cross-Layer Infrastructure for Multi-Dimensional Indexing, Querying and Routing in Wireless Ad-Hoc and Sensor Networks

Large scale wireless ad-hoc networks of computers, sensors, PDAs etc. (i.e. nodes) are revolutionizing connectivity and leading to a paradigm shift from centralized systems to highly distributed and dynamic environments. A plethora of routing algorithms have been proposed for the network path discovery ranging from broadcasting/flooding-based approaches to those using Global Positioning Systems (GPS). In this paper we propose a novel decentralized infrastructure that self-organizes wireless devices in an ad-hoc network, where each node has one or more virtual coordinates through which both message routing and data management occur without reliance on either flooding/broadcasting operations or GPS. The resulting ad-hoc network does not suffer from the dead-end problem, which happens in geographic-based routing when a node is unable to locate a neighbor closer to the destination than itself. The multi-dimensional data management capability will be described showing, as an example, how the location service reduces to a simple query, like for any other data type. Extensive performance analysis and experiments have been conducted and the results compared to GPSR, which is considered the most efficient routing solution not using broadcast operations. Our approach shows significant performance gains

W*-Grid: A Robust Decentralized Cross-layer Infrastructure for Routing and Multi-Dimensional Data Management in Wireless Ad-Hoc Sensor Networks

Network coding is an emerging field of research with sound and mature theory supporting it. Recent works shows that it has many benefits like improved fault tolerance, higher flexibility in selection of file parts to transfer and resiliency to network partitions [4, 3]. Despite those appealing properties there is no wide usage of network coding in real file sharing applications. In this work, we try to bridge the gap between theory of network coding and practice. From the one hand, we deploy one the most successful file sharing client, the BitTorrent client. We use the BitTorrent algorithm for optimizing the neighbor selections for maximizing the upload bandwidth. From the other hand, we propose several simple heuristics that improve significantly the efficiency of the network coding deployed. In a nutshell, we propose computation intensive variant of network coding that can be applied to most of the existing network coding protocols. By changing the random selection of coded parts to a selection based on feedback from the network, we significantly improve the network utilization and the efficiency of the protocol. In this paper we report our work in progress building the BitCod client. Using extensive simulations we demonstrate that our technique can compete with the performance of the state-of-the-art BitTorrent [2] file sharing client. Next, we plan to implement and test a prototype of the BitCod client over the WAN.Sensor networks are usually composed by small units able to sense and transmit to a sink elementary data which are successively processed by an external machine. However recent improvements in the memory and computational power of sensors, together with the reduction of energy consumptions, are rapidly changing the potential of such systems, moving the attention towards data-centric sensor networks. This paper presents W*-Grid, a fully decentralized and robust infrastructure for self-organizing data- centric sensor networks, where wireless communications occur through multi-hop routing among devices. The solution extends W-Grid by strongly improving the network recovery performance from link and/or device failures. In particular W*-Grid guarantees, by construction, at least two disjoint paths between each couple of nodes. This implies that the recovery in W*-Grid occurs without broadcasting transmissions and guaranteeing robustness while drastically reducing the energy consumption. An extensive number of simulations show the efficiency, robustness and traffic load of resulting networks under several scenarios of device density and of number of coordinates.

Routing and Localization Services in Self-Organizing Wireless Ad-Hoc and Sensor Networks Using Virtual Coordinates

Large scale wireless ad-hoc networks of computers, sensors, PDAs etc. (i.e. nodes) are revolutionizing connectivity and leading to a paradigm shift from centralized systems to highly distributed systems. A plethora of routing algorithms have been proposed to support path discovery into this class of networks, ranging from broadcasting/flooding approaches to global positioning systems (GPS). W-Grid is a novel infrastructure whose self-organizing routing and localization services enable message routing and data management without reliance on flooding/broadcasting operations or GPS. The resulting ad-hoc network does not suffer from the dead-end problem, which occurs in geographic-based routing when a node is unable to locate a neighbor closer to the destination than itself. As an example of data management we present a location service that allows a device to send messages to any another node without knowing its position. Extensive performance analysis and experiments have been conducted, and the results compared to GPSR, which is considered to be the most efficient solution not using broadcast operations but exploiting nodes position. Analyses show that the difference between the performance of our approach and GPSR is minimal and therefore very interesting, since no GPS is used