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A super-peer is a node in a peer-to-peer network that operates both as a server to a set of clients, and as an equal in a network of super-peers. Super-peer networks strike a balance between the inherent efficiency of centralized search, and the autonomy, load balancing and robustness to attacks provided by distributed search. Furthermore, they take(More)
Emerging economic P2P applications share the common need for an efficient, secure payment mechanism. In this paper, we present PPay, a micropayment system that exploits unique characteristics of P2P systems to maximize efficiency while maintaining security properties. We show how the basic PPay protocol far outperforms existing micropayment schemes, while(More)
Peer-to-peer systems enable access to data spread over an extremely large number of machines. Most P2P systems support only simple lookup queries. However, many new applications, such as P2P photo sharing and massively multi-player games, would benefit greatly from support for multidimensional range queries. We show how such queries may be supported in a(More)
In addition to indexes and materialized views, horizontal and vertical partitioning are important aspects of physical design in a relational database system that significantly impact performance. Horizontal partitioning also provides manageability; database administrators often require indexes and their underlying tables partitioned identically so as to(More)
Peer-to-Peer (P2P) systems are large-scale, autonomous, decentralized systems where computers pool their resources. Their architecture and their scale lead to challenging performance and security issues. The purpose of the paper is to highlight the problems that P2P systems have to address in two particular aspects: search and security. Summary While P2P(More)
Current search techniques over unstructured peer-to-peer networks rely on intelligent forwarding-based techniques to propagate queries to other peers in the network. Forwarding techniques are attractive because they typically require little state and offer robustness to peer failures; however they have inherent performance drawbacks due to the overhead of(More)
Structural joins are a fundamental operation in XML query processing and a large body of work has focused on index-based algorithms for executing them. In this paper, we describe how two well-known index features -- path indices and ancestor information -- can be combined in a novel way to replace one or more of the physical index cursors in a structural(More)