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Power consumption is a major design issue in modern microprocessors. Hence, power reduction techniques, like dynamic voltage scaling (DVS), are being widely implemented. Unfortunately, they impact on the task execution time so difficulting schedulability of hard real-time applications. To deal with this problem, this paper proposes a power-aware scheduler for coarse-grain embedded multicore processors...
One of the central tasks of EUFORIA is to port, parallelise, and optimise fusion simulation codes, developed at individual research institutes in Europe. There are three supercomputer centres involved in the project located at Barcelona, Edinburgh, and Helsinki. For some of the fusion codes simply porting them to one of the supercomputers represents a major advancement in the use of the codes, as...
FAFNER is code developed by Lister which simulates by Monte Carlo methods the Neutral Beam Injection (NBI) technology, one of the most extended heating methods for fusion devices. To the date, FAFNER has been usually run at CIEMAT adapted to the TJ-II helical axis stellarator on shared memory Cray architecture machines. From this version, FAFNER has been ported to the Grid in the framework of the...
It is important to analyse the privacy impact of Intrusion Detection System (IDS) rules, in order to understand and quantify the privacy-invasiveness of network monitoring services. The objective in this paper is to classify Snort rules according to the risk of privacy violations in the form of leaking sensitive or confidential material. The classification is based on a ruleset that formerly has been...
We investigate the scalability of the hypergraph-based sparse matrix partitioning methods with respect to the increasing sizes of matrices and number of nonzeros. We propose a method to rowwise partition the matrices that correspond to the discretization of two-dimensional domains with the five-point stencil. The proposed method obtains perfect load balance and achieves very good total communication...
A very ambitious objective in the field of policy-based systems is the provision of an intuitive and transparent way for policy specification, refinement and enforcement. This is one of the key enabling technologies for a simplified security management of complex networked environments. Currently, security policies are enforced by configuring the end devices by means of low-level device-specific parameters...
A fundamental problem in large scale Grids is the need for efficient and scalable techniques for resource discovery and scheduling. In traditional resource scheduling systems a single scheduler handles information about all computing resources and schedules jobs. This centralized approach has a serious scalability problem, since it introduces a bottleneck, as well as a single point of failure. Some...
We present a Parallel Genetic Algorithm (PGA) for the solution of a constrained global optimization problem arising in the detection of gravitational waves through the matched filter technique. This is a hard problem, since it has a black-box stochastic objective function, which is highly nonlinear, multiextremal and computationally expensive. Our PGA uses multiple subpopulations (demes) that evolve...
New service providers, completely separated from the Internet Service Providers (ISP), are growing today in the Internet scenario to create new multimedia services through the P2P approach. These providers are manifesting great interest not only for classical multimedia applications, like video streaming and video on demand, but also for other applications, like for example video-conferencing, multi-party...
In this paper, we consider the problem of the online allocation of a very large number of identical tasks on a master-slave platform. Initially, several masters hold or generate tasks that are transfered and processed by slave nodes. The goal is to maximize the overall throughput achieved using this platform, i. e., the (fractional) number of tasks that can be processed within one time unit. We model...
The rapid growth in the throughput to cost ratio of experimental data production technologies is generating vast amounts of scientific data, often organized into "large" objects (genomes, bio-images) exhibiting complex internal structures. Frequently, datasets must be shared between multiple research groups interested not only in the final results, but also in how they are produced. The...
Transactional Memory is a novel, promising approach for simplifying parallel programming and increasing its acceptance and diffusion. Until now, almost all the research work on TM has been focused on shared-memory architectures, while very limited effort has been dedicated to TM on distributed-memory architectures. In this paper, we propose an extension of the transactional engine DSTM2, originally...
This paper presents the design of a P2P data persistent platform. Durable access and integrity of the data are ensured despite massive attacks. This platform, named DataCube, exploits the properties of cluster-based peer-to-peer substrates to implement a compound of full replication and rateless erasure codes. DataCube guarantees durable access and integrity of data despite adversarial attacks. In...
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