No abstract

Trust Management is increasingly playing a major role especially with the growing need for security in decentralized, unsecured networks like peer-to-peer networks. Effective trust management solutions especially one geared towards handling trust in peer groups within peer communities are the key to handle the emerging security threats and scalability issues. Using a delegation infrastructure can provide a tremendous boost in terms of autonomy and division of labor in group based peer-to-peer communities.In our work we propose an effective trust system built on top of a peer group infrastructure that not only manages trust within communities but also between different communities. We also propose a delegation infrastructure that can be applied effectively to any grouped peer-to-peer community.

No abstract

is increasingly important in databases, discovered knowledge is not always useful to users. It is mainly because the discovered knowledge does not t user's interests, or it may be redundant o r inconsistent with a priori knowledge. Knowledge discovery in databases depends critically on how w ell a database is characterized and how consistently the existing and discovered knowledge is evolved. This paper describes a novel concept for knowledge discovery and evolution in databases. The key issues of this work include: using a database query to discover new rules; using not only positive examples answer to a query but also negative examples to discover new rules; harmonizing existing rules with the new rules. The main contribution of this paper is the development of a new tool for 1 characterizing the exceptions in databases and 2 evolving knowledge as a database evolves. Keywords| Knowledge discovery, database mining, active database evolution, knowledge re nement, expertise transfer.

The information on the web is growing at a very fast pace. In this ever-accumulating data, the volume of information being exchanged using peer-to-peer applications is on the rise in recent times. As peer-to-peer applications like file sharing, distributed computing and instant messaging are gaining popularity, security issues related to these applications are being taken up more seriously. In this paper, we focus mainly on two important security issues related to the aspect of peer-to-peer file sharing. First of these is the problem of "Peer Selection", where the notion of security deals with the identification and prevention of peers that display malicious tendencies in their behavior. The second issue is "Request Resolution" which comes into play when a peer needs to decide among the received requests for its resources. Request resolution is of vital importance since some of these requests may tend to exhaust the peer's serving capabilities (like processing capacity and bandwidth), so that it can't respond to any further requests normally. Consequences of such a maligned request may result in the peer loosing its trust among other peers as well as being branded malicious. In this paper, we show how to model group trust for peer-to-peer access control so as to make them secure and thus provide a redressal to the above-mentioned issues.