In this paper, we present a family of domain decomposition based on Aitken like acceleration of the Schwarz method seen as an iterative procedure with linear rate of convergence. This paper is a generalization of the ...
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ISBN:
(纸本)3540225234
In this paper, we present a family of domain decomposition based on Aitken like acceleration of the Schwarz method seen as an iterative procedure with linear rate of convergence. This paper is a generalization of the method first introduced in Garbey and Tromeur-Dervout [2001] that was restricted to Cartesian grids. The general idea is to construct an approximation of the eigenvectors of the trace transfer operator associated to dominant eigenvalues and accelerate these components after few Schwarz iterates. We consider here examples with the finite volume approximation on general quadrangle meshes of Faille [1992] and finite element discretization.
The objectives of simulating the hydraulic behavior of a water supply network, being either real or planned, focus upon identifying flow, pressure and velocities, following time variant system's operation or the p...
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ISBN:
(纸本)0784407924
The objectives of simulating the hydraulic behavior of a water supply network, being either real or planned, focus upon identifying flow, pressure and velocities, following time variant system's operation or the propagation of water quality in the network, supporting leak detection, verifying the hydraulic impact of different system's elements, guiding gauging and calibration. Existing simulation models represented by available software show different capacities regarding control devices, including pressure control valves, pressure sustaining valves, flow control valves, check valves, speed regulated pumps - operated combined and simultaneously where convergence may not be obtained. Since a rigorous mathematical approach is lacking the system's behavior is presently treated heuristically without guarantee of success. Consequently a new mathematical approach has been derived and is presented here. First, the hydraulic simulation is conceived as optimization of the system's 'Content' and 'Co-Content' functions. Second, regarding flow control devices, Convex Analysis is utilized to allow a generalization of the hydraulic equations of system's elements in the form of subdifferential mappings leading to Kuhn-Tucker conditions, amenable to solution. Third, regarding pressure control devices, the definition of a Nash Equilibrium, according to Game Theory, between the 'Co-Content' and additional minimizing problems, describing the system behavior of the devices, also leads to a solution. Hence, arbitrary flow and pressure controlling devices can now be incorporated in water supply network simulation. Convergence is assured if the system's physics are feasible. The approach has been implemented as part of the water supply network simulation & optimization model KANET. Copyright ASCE 2005.
A Service Class Description (SCD) is an effective meta-data based approach for discovering Deep Web sources whose data exhibit some regular patterns. However, it is tedious and error prone to create an SCD description...
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This paper deals with the challenging problem of performance analysis for Java programs. We describe procedures and requirements for instrumenting, monitoring, and analyzing distributed Java codes, and introduces Aksu...
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ISBN:
(纸本)9780780390744
This paper deals with the challenging problem of performance analysis for Java programs. We describe procedures and requirements for instrumenting, monitoring, and analyzing distributed Java codes, and introduces Aksum, a highly customizable and flexible system for performance analysis that helps programmers to semi-automatically locate and understand performance problems in parallel and distributed Java programs. We also describe a sophisticated agent architecture as part of Aksum for static and dynamic instrumentation of Java programs. Experiments are presented for a widely distributed application running on a heterogeneous set of machines with different operating systems to illustrate the usefulness of our approach.
Although new Java virtual machines provide an API to obtain raw performance data, it is still the task of a skillful performance analysis tool to take all the strategic decisions for instrumentation and performance an...
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Although new Java virtual machines provide an API to obtain raw performance data, it is still the task of a skillful performance analysis tool to take all the strategic decisions for instrumentation and performance analysis of distributed Java programs. In this paper we demonstrate two new tools. Twilight and Aksum, which try to automatically instrument code regions, to determine what performance data to collect, to interpret performance data, and to relate the bottlenecks found back to source code. We present experiments with a widely distributed Java application running on a heterogeneous set of machines with different operating systems to demonstrate the efficacy of our tools
One of the main obstacles to the efficient solution of scientific problems is the problem of tuning software, both to the available architecture and to the user problem at hand. We describe approaches for obtaining tu...
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During the last few years new functionalities of RNA have been discovered, renewing the need for computational tools for their analysis. To this respect, multiple sequence alignment is an essential step in finding str...
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We propose a new random beamforming technique in forward link multiuser MIMO systems that exploits efficient multiuser diversity and spatial multiplexing gain. The common channels are allocated to more than one user s...
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We propose a new random beamforming technique in forward link multiuser MIMO systems that exploits efficient multiuser diversity and spatial multiplexing gain. The common channels are allocated to more than one user simultaneously and multiple antennas at the receivers are used for interference nulling, resulting in higher throughput and reduced average waiting time. We show that the throughput of the proposed scheme outperforms the upper bound of the conventional scheme.
We investigate preconditioned iterative solutions of large dense complex valued matrices arising from discretizing the hybrid integral equations of electromagnetic scattering. Due to the specific data pattern, we prop...
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