The open and decentralized nature of a peer-to-peer network makes it susceptible to intruders and malicious peers. As a result, it is required to offer a mechanism to rank the participants and to moderate the interact...
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The open and decentralized nature of a peer-to-peer network makes it susceptible to intruders and malicious peers. As a result, it is required to offer a mechanism to rank the participants and to moderate the interactions between them according to this information. Moreover, several systems are totally organized according to participants ranks. This paper presents an anonymous and secure protocol for maintaining and accessing trust information, using cryptography, for decentralized peer-to-peer systems. We offer anonymity of the peer that computes and stores the trust value for another peer. The system is such that voters have secret ballot, votes stay in the system even when the voters have logged out and the decision making process is fast. Experimental testing has been conducted using Oversim, a flexible simulator.
Modular parallel applications can be structured by parallel tasks that implement the modules. The dependence structure of such parallel applications gives rise to a scheduling problem, which is determined either stati...
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Modular parallel applications can be structured by parallel tasks that implement the modules. The dependence structure of such parallel applications gives rise to a scheduling problem, which is determined either statically at compile-time, e.g. by using a suitable compiler tool, or dynamically at runtime. In this article, we present a semi-dynamic execution scheme for applications structured by parallel tasks. This execution scheme combines a statically computed schedule with a dynamic load balancing that can adapt the schedule at runtime of the application. In this way, it is possible to reduce load imbalances between processor groups that may exist in the static schedule resulting from platform heterogeneity or from an imprecise cost prediction. Experimental results for several scientific applications show that the semi-dynamic execution scheme leads to lower execution times compared to a static execution on a tightly coupled heterogeneous platform.
Next Generation DNA Sequencing platforms produce significantly larger amounts of data compared to early Sanger technology sequencers. In addition to the challenges of data-management that arise from unprecedented volu...
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We present an algorithm-based recovery scheme for Exascale computing, which uses both data dependencies and communication-induced redundancies of parallel codes to tolerate fault with low overhead. For some applicatio...
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We present an algorithm-based recovery scheme for Exascale computing, which uses both data dependencies and communication-induced redundancies of parallel codes to tolerate fault with low overhead. For some applications, our scheme significantly reduces checkpoint size and introduces no overhead when there is no actual failure in the computation. Fault tolerance Newton's method by tailoring our scheme to the algorithm is performed. Numerical simulations indicate that our scheme introduces much less overhead than diskless check pointing does.
P2PDC is an environment for high performance peer to peer computing that allows direct communication between peers. This environment is based on P2PSAP, a self adaptive communication protocol. P2PDC is suited to the s...
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P2PDC is an environment for high performance peer to peer computing that allows direct communication between peers. This environment is based on P2PSAP, a self adaptive communication protocol. P2PDC is suited to the solution of large scale numerical simulation problems via distributed iterative methods. dPerf is a performance prediction environment for parallel and distributed applications, with primary interest in programs written in C, C++, Fortran for P2PDC. The dPerf performance prediction tool makes use of static and dynamic analyses combined with trace-based simulation. In this paper, we present a decentralized version of P2PDC and show how dPerf predicts performance for the P2PDC environment. We present new features of P2PDC aimed at making it more scalable and robust. Through experiments with P2PDC and dPerf, we show how to properly choose a peer to peer computing system which can match the computing power of a cluster.
The proceedings contain 40 papers. The topics discussed include: FAST: a generic framework for flash-aware spatial trees;MIDAS: multi-attribute indexing for distributed architecture systems;thread-level parallel index...
ISBN:
(纸本)9783642229213
The proceedings contain 40 papers. The topics discussed include: FAST: a generic framework for flash-aware spatial trees;MIDAS: multi-attribute indexing for distributed architecture systems;thread-level parallel indexing of update intensive moving-object workloads;efficient processing of Top-k spatial keyword queries;retrieving k-nearest neighboring trajectories by a set of point locations;towards reducing taxicab cruising time using spatio-temporal profitability maps;computing the cardinal direction development between moving points in spatio-temporal databases;continuous probabilistic count queries in wireless sensor networks;geodetic point-in-polygon query processing in oracle spatial;MSSQ: manhattan spatial skyline queries;inverse queries for multidimensional spaces;efficient evaluation of k-NN queries using spatial mashups;and SeTraStream: semantic-aware trajectory construction over streaming movement data.
This paper deals with the numerical solution of financial applications, more specifically the computation of American and European options derivatives modelled by boundary values problems. In such applications we have...
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This paper deals with the numerical solution of financial applications, more specifically the computation of American and European options derivatives modelled by boundary values problems. In such applications we have to solve large-scale algebraic linear systems. We concentrate on synchronous and asynchronous parallel iterative algorithms carried out on peer-to-peer networks. The properties of the operators arising in the discretized problem ensure the convergence of the parallel iterative synchronous and asynchronous algorithms. Computational experiments performed on peer-to-peer networks are presented and analyzed.
We consider the problem of implementing a security protocol in such a manner that secrecy of sensitive data is not jeopardized. The implementation is assumed to take place in the context of a language named Join Voyag...
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We consider the problem of implementing a security protocol in such a manner that secrecy of sensitive data is not jeopardized. The implementation is assumed to take place in the context of a language named Join Voyagers used to program a Peer-to-Peer network using object oriented techniques and Join methods. A mobile agent is an object that can migrate throughout a heterogeneous network of computers, under its own control, in order to perform tasks using resources of these nodes. We develop a basic architecture to express security protocols for communication and strong migration, or to enforce cryptographic primitives based on SPI calculus. These protocols rely on cryptography and on communication channels with properties like authenticity and privacy. This article will present also a series of aspects related to mobile code security, namely the protection of hosts receiving a malicious code and the protection of a mobile code within a malicious host from our programmable Peer-to-Peer network.
Due to its ability to provide requested resources on demand, the use of cloud computing for data-intensive computing is expected to skyrocket in the coming years. The present IaaS cloud infrastructure is designed such...
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Due to its ability to provide requested resources on demand, the use of cloud computing for data-intensive computing is expected to skyrocket in the coming years. The present IaaS cloud infrastructure is designed such that the compute cloud and the storage cloud are separate components. However, the design has one major problem, namely a trade-off has to be made between the network cost and storage performance. To cope with these problems, we are proposing high performance file system service in compute cloud that transparently utilizes file access locality on dynamic configuration of cloud computing infrastructure. We evaluated the system using micro benchmarks, MapReduce applications, and MPI-IO applications. Our system shows the scalable file I/O performance.
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