2003
Autores
Pereira, J; do Minho, U; Rodrigues, L; de Lisboa, U; Monteiro, M; Oliveira, R; Kermarrec, A;
Publicação
22ND INTERNATIONAL SYMPOSIUM ON RELIABLE DISTRIBUTED SYSTEMS, PROCEEDINGS
Abstract
Epidemic, or probabilistic, multicast protocols have emerged as a viable mechanism to circumvent the scalability problems of reliable multicast protocols. However most existing epidemic approaches use connectionless transport protocols to exchange messages and rely on the intrinsic robustness of the epidemic dissemination to mask network omissions. Unfortunately, such an approach is not network-friendly since the epidemic protocol makes no effort to reduce the load imposed on the network when the system is congested. In this paper we propose a novel epidemic protocol whose main characteristic is to be network-friendly This property is achieved by relying on connection-oriented transport connections, such as TCP/IP to support the communication among peers. Since during congestion messages accumulate in the border of the network, the protocol uses an innovative buffer management scheme, that combines different selection techniques to discard messages upon overflow. This technique improves the quality of the information delivered to the application during periods of network congestion. The protocol has been implemented and the benefits of the approach are illustrated using a combination of experimental and simulation results.
2003
Autores
Pinto, JS;
Publicação
Electronic Notes in Theoretical Computer Science
Abstract
This paper presents an implementation device for the weak reduction of interaction nets to interface normal form. The results produced by running several benchmarks are given, suggesting that weak reduction greatly improves the performance of the interaction combinators-based implementation of the ?-calculus. © 2003 Published by Elsevier Science B.V.
2003
Autores
Baquero, C; Lopes, N;
Publicação
Operating Systems Review
Abstract
Distributed Hash Tables are the core technology on a significant share of system designs for Peer-to-Peer information sharing. Typically, a location mechanism is provided and object identifiers act as keys in the index of object locations. When introducing a search mechanism, when single words an used as keys, the key image cardinality will be driven by the word popularity and most of the present designs will be unable to load balance the index among the nodes. We present two contributions: A design that allows participating nodes to load balance the indexing of popular keys and avoid content hot-spots on single nodes; A distributed mechanism for probabilistic filtering of popular keys (with low search relevance) that paves the way for scalable full content indexing.
2003
Autores
Bryant, BR; Saraiva, J;
Publicação
LDTA@ETAPS
Abstract
2003
Autores
Bryant, BR; Saraiva, J;
Publicação
Electr. Notes Theor. Comput. Sci.
Abstract
2003
Autores
Saraiva, J; Schneider, S;
Publicação
36th Hawaii International Conference on System Sciences (HICSS-36 2003), CD-ROM / Abstracts Proceedings, January 6-9, 2003, Big Island, HI, USA
Abstract
This paper presents techniques for the design and implementation of domain specific languages. Our techniques are based on higher-order attribute grammars. Formal languages are specified in the classical attribute formalism and domain specific languages are embedded in the specification via higher-order attributes. We present a domain specific language for pretty-printing and we show how such language can be easily embedded in the specification of a powerful spreadsheet-like tool. From such specification an incremental implementation is automatically derived and the first results are presented. © 2003 IEEE.
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