A novel algorithm for performing parallel, distributed computer simulations on the Internet using Internet protocol (IP) control messages is introduced. The algorithm employs carefully constructed Internet control mes...
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A novel algorithm for performing parallel, distributed computer simulations on the Internet using Internet protocol (IP) control messages is introduced. The algorithm employs carefully constructed Internet control message protocol (ICMP) packets that enable the required computations to be completed as part of the standard IP communication protocol. After providing a detailed description of the algorithm, experimental applications in the areas of stochastic neural networks and deterministic cellular automata axe discussed. As an example of the algorithm's potential power, a simulation of a deterministic cellular automaton involving 10(5) Internet-connected devices was performed.
In this paper we analyze a two-level preconditioner for finite element systems arising in approximations of second order elliptic boundary value problems by Crouzeix-Raviart non-conforming triangular linear elements. ...
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We present an efficient and scalable coarse grained multicomputer (CGM) coloring algorithm that colors a graph G with at most Delta + 1 colors where A is the maximum degree in G. This algorithm is given in two variant...
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We present an efficient and scalable coarse grained multicomputer (CGM) coloring algorithm that colors a graph G with at most Delta + 1 colors where A is the maximum degree in G. This algorithm is given in two variants: randomized and deterministic. We show that on a p-processor CGM model the proposed algorithms require a parallel time of O(\G\/p) and a total work and overall communication cost of O(\G\). These bounds correspond to the average case for the randomized version and to the worst case for the deterministic variant. (C) 2003 Elsevier B.V. All rights reserved.
Deadlock prevention for routing messages has a central role in communication networks, since it directly influences the correctness of parallel and distributed systems. In this paper, we extend some of the computation...
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Deadlock prevention for routing messages has a central role in communication networks, since it directly influences the correctness of parallel and distributed systems. In this paper, we extend some of the computational results presented in Second Colloquium on Structural Information and Communication Complexity (SIROCCO), Carleton University Press, 1995, pp. 1-12 on acyclic orientations for the determination of optimal deadlock-free routing schemes. In this context, minimizing the number of buffers needed to prevent deadlocks for a set of communication requests is related to finding an acyclic orientation of the network which minimizes the maximum number of changes of orientations on the dipaths realizing the communication requests. The corresponding value is called the rank of the set of dipaths. We first show that the problem of minimizing the rank is NP-hard if all shortest paths between the couples of nodes wishing to communicate have to be represented and even not approximable if only one shortest path between each couple has to tie represented. This last result holds even if we allow an error which is any sublinear function in the number of couples to be connected. We then improve some of the known lower and upper bounds on the rank of all possible shortest dipaths between any couple of vertices for particular topologies, such as grids and hypercubes, and we find tight results for tori. (C) 2002 Elsevier Science B.V. All rights reserved.
The numerical solution of 3D linear elasticity equations is considered. The problem is described by a coupled system of second-order elliptic partial differential equations. This system is discretized by trilinear par...
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The numerical solution of 3D linear elasticity equations is considered. The problem is described by a coupled system of second-order elliptic partial differential equations. This system is discretized by trilinear parallelepipedal finite elements. The preconditioned conjugate gradient iterative method is used for solving of the large-scale linear algebraic systems arising after the finite element method (FEM) discretization of. the problem. Displacement decomposition technique is applied at the first step to construct a preconditioner using the decoupled block-diagonal part of the original matrix. Then circulant block-factorization is used for preconditioning of the obtained block-diagonal matrix. Both techniques, displacement decomposition and circulant block-factorization, are highly parallelizable. A parallel algorithm is invented for the proposed preconditioner. The theoretical analysis of the execution time shows that the algorithm is highly efficient for coarse-grain parallel computer systems. A portable MPI parallel FEM code is developed. Numerical tests for real-life engineering problems of the geomechanics in geosciences on a number of modem parallel computers are presented. The reported speed-up and parallel efficiency well illustrate the parallel features of the proposed method and its implementation. (C) 2002 IMACS. Published by Elsevier Science B.V. All rights reserved.
Many of the operations to eliminate complaints concerning respiration impairments fail. In order to improve the success rate, it is important to recognize the responsiveness of the flow field within the nasal cavities...
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Many of the operations to eliminate complaints concerning respiration impairments fail. In order to improve the success rate, it is important to recognize the responsiveness of the flow field within the nasal cavities. Therefore, we are developing a computer assisted surgery (CAS) system that combines computational fluid dynamics (CFD) and virtual reality (VR) technology. However, the primary prerequisite for VR-based applications is real-time interaction. A single graphics workstation is not capable of satisfying this condition and of simultaneously calculating flow features employing the huge CFD data set. In this paper, we will present our approach of a distributed system that relieves the load on the graphics workstation and makes use of an "off-the-shelf'' parallel Linux cluster calculating streamlines. Moreover, we introduce first results and discuss remaining difficulties.
The evaluation of a domain integral is the dominant bottleneck in the numerical solution of viscous flow problems by vorticity methods, which otherwise demonstrate distinct advantages over primitive variable methods. ...
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The evaluation of a domain integral is the dominant bottleneck in the numerical solution of viscous flow problems by vorticity methods, which otherwise demonstrate distinct advantages over primitive variable methods. By applying a Bames-Hut multipole acceleration technique, the operation count for the integration is reduced from O(N-2) to O(N log N), while the memory requirements are reduced from O(N-2) to O(N). The algorithmic parameters that are necessary to achieve such scaling are described. The parallelization of the algorithm is crucial if the method is to be applied to realistic problems. A parallelization procedure which achieves almost perfect scaling is shown. Finally, numerical experiments on a driven cavity benchmark problem are performed. The actual increase in performance and reduction in storage requirements match theoretical predictions well, and the scalability of the procedure is very good. Copyright (C) 2003 John Wiley Sons, Ltd.
Although evolutionary algorithm is a powerful optimization tool, its computation cost involved in terms of time and hardware increases as the size and complexity of the problem increases. In this paper, a Java-based d...
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ISBN:
(纸本)0780378040
Although evolutionary algorithm is a powerful optimization tool, its computation cost involved in terms of time and hardware increases as the size and complexity of the problem increases. In this paper, a Java-based distributed evolutionary computing package (Paladin-DEC) is presented by exploiting the inherent parallel nature of evolutionary algorithms. The package enhances the concurrent processing and performance of evolutionary algorithms by allowing inter-communications of subpopulations among various computers over the Internet. The Paladin-DEC is incorporated with the features of security, scalability and fault tolerance, and is capable of keeping data integrity throughout the computation. The effectiveness and advantages of the Paladin-DEC are illustrated through a case study of drug scheduling in cancer chemotherapy.
The numerical solution of 3D linear elasticity equations is considered. The problem is described by a coupled system of second-order elliptic partial differential equations. This system is discretized by trilinear par...
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The numerical solution of 3D linear elasticity equations is considered. The problem is described by a coupled system of second-order elliptic partial differential equations. This system is discretized by trilinear parallelepipedal finite elements. The preconditioned conjugate gradient iterative method is used for solving of the large-scale linear algebraic systems arising after the finite element method (FEM) discretization of. the problem. Displacement decomposition technique is applied at the first step to construct a preconditioner using the decoupled block-diagonal part of the original matrix. Then circulant block-factorization is used for preconditioning of the obtained block-diagonal matrix. Both techniques, displacement decomposition and circulant block-factorization, are highly parallelizable. A parallel algorithm is invented for the proposed preconditioner. The theoretical analysis of the execution time shows that the algorithm is highly efficient for coarse-grain parallel computer systems. A portable MPI parallel FEM code is developed. Numerical tests for real-life engineering problems of the geomechanics in geosciences on a number of modem parallel computers are presented. The reported speed-up and parallel efficiency well illustrate the parallel features of the proposed method and its implementation. (C) 2002 IMACS. Published by Elsevier Science B.V. All rights reserved.
Digital modulation based on FSK is widely used in HF data communication. This is due to simplicity in implementation by noncoherent detection and robustness due noise and phase synchronization error. Hardware based de...
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ISBN:
(纸本)0780381149
Digital modulation based on FSK is widely used in HF data communication. This is due to simplicity in implementation by noncoherent detection and robustness due noise and phase synchronization error. Hardware based design using FPGA can reduced system size. The proposed modulation integrates both the transmitter and receiver modules into a single FPGA. Further reduction in components is achieved by adopting a multiplierless and parallel algorithm at the receiver module. This is proven by comparing with conventional noncoherent detection algorithm.
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