The generalized assignment problem is a representative NP-hard problem, for which many heuristic algorithms are known. In this article, two parallel heuristic algorithms are proposed, which are based on the ejection c...
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The generalized assignment problem is a representative NP-hard problem, for which many heuristic algorithms are known. In this article, two parallel heuristic algorithms are proposed, which are based on the ejection chain local search (EC) proposed by Yagiura et al. One is a simple parallelization called multistart parallel EC (MPEC) and the other is cooperative parallel EC (CPEC). In MPEC each search process independently explores search space while in CPEC search processes share partial information to cooperate with each other. The experimental results with 9 computers for large benchmark instances show that (1) MPEC and CPEC, respectively, run twice and 4 times faster than EC, and (2) compared to EC, the difference in quality between obtained solutions and theoretical lower bounds is reduced to 3/4 and 2/3 by MPEC and CPEC, respectively. It is said that these methods give us full benefit of parallelization, speedup and improvement for quality of solutions.
The processing of three-dimensional(3-D) objects from 3-D digital image data is an important task in the image processing and the computer vision *** distance transform(DT) is extensively applied in the image proc...
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The processing of three-dimensional(3-D) objects from 3-D digital image data is an important task in the image processing and the computer vision *** distance transform(DT) is extensively applied in the image processing and computer vision areas as a key operation. In a two or three-dimensional image array,the computation of distance transform(DT) is an important task. With the increasing application of 3D voxel images,it is useful to consider the distance transform of a 3D digital image *** order to provide the efficient transform computations, parallelism is *** develop parallel algorithms for the three-dimensional Euclidean distance transform (3D-EDT) on the SIMD hypercube *** time complexity of our parallel algorithm is O(log N) for an N×JV×N image array using JV3 processors.A generalized parallel algorithm for the 3D-EDT is also proposed and it runs O((N/p) log(N) +(N/p) log p) time for an N×N×N binary image array on the SIMD hypercube computer using p PE's,where 1≤p≤N.
Projections are widely used in machine vision, volume rendering, and computer graphics. For applications with 3D volume data, we design a parallel projection algorithm on SIMD mesh-connected computers and implement th...
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Projections are widely used in machine vision, volume rendering, and computer graphics. For applications with 3D volume data, we design a parallel projection algorithm on SIMD mesh-connected computers and implement the algorithm on the parallel Algebraic Logic (PAL) computer. The algorithm is a parallel ray casting algorithm for both orthographic and perspective projections. It decomposes a volume projection into two transformations that can be implemented in the SIMD fashion to solve the data distribution and redistribution problem caused by non-regular data access patterns in volume projections.
Two parallel algorithms are presented for solving the minimum cost spanning tree problem in any undirected graph. These algorithms are parallel formulations of DHEA algorithm using Depth-First Search of the graph, The...
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Two parallel algorithms are presented for solving the minimum cost spanning tree problem in any undirected graph. These algorithms are parallel formulations of DHEA algorithm using Depth-First Search of the graph, The cost-optimality of both algorithms are investigated.
A new mathematical morphology-based algorithm is proposed to achieve automatic center location of non-eye typhoon. The center of a non-eye typhoon is near the geometric center of the cloud system and has higher temper...
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ISBN:
(纸本)0780378407
A new mathematical morphology-based algorithm is proposed to achieve automatic center location of non-eye typhoon. The center of a non-eye typhoon is near the geometric center of the cloud system and has higher temperature. For each infrared satellite cloud image, the locating procedures are as follows: a) noises filtering, b) main cloud systems segmenting, c) center locating and d) multispectral image verification. The algorithms are based on operations of mathematical morphology, and designed in IBM SP2 massively parallel computer. The experiment results show that the algorithm locates the centers of most non-eye typhoons successfully and achieves faster, more precise and non-human interactive non-eye typhoon center positioning.
A new mathematical morphology-based algorithm is proposed to achieve automatic center location of non-eye *** center of a non-eye typhoon is near the geometric center of the cloud system and has higher *** each infrar...
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A new mathematical morphology-based algorithm is proposed to achieve automatic center location of non-eye *** center of a non-eye typhoon is near the geometric center of the cloud system and has higher *** each infrared satellite cloud image,the locating procedures are as follows:a) noises filtering,b) main cloud systems segmenting,c) center locating and d) multispectral image *** algorithms are based on operations of mathematical morphology,and designed in IBM SP2 massively parallel *** experiment results show that the algorithm locates the centers of most non-eye typhoons successfully and achieves faster,more precise and non-human interactive non-eye typhoon center positioning.
We present faster sequential and parallel algorithms for computing the solvent accessible surface area (ASA) of protein molecules. The ASA is computed by finding the exposed surface areas of the spheres obtained by in...
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We present faster sequential and parallel algorithms for computing the solvent accessible surface area (ASA) of protein molecules. The ASA is computed by finding the exposed surface areas of the spheres obtained by increasing the van der Waals radii of the atoms with the van der Waals radius of the solvent. Using domain specific knowledge, we show that the number of sphere intersections is only O(n), where n is the number of atoms in the protein molecule. For computing sphere intersections, we present hash-based algorithms that run in O(n) expected sequential time and O(n/p) expected parallel time and sort-based algorithms that run in worst-case O(n log n) sequential time and O(n log n/p) parallel time. These are significant improvements over previously known algorithms which take O(n(2)) time sequentially and O(n(2)/p) time in parallel. We present a Monte Carlo algorithm for computing the solvent accessible surface area. The basic idea is to generate points uniformly at random on the surface of spheres obtained by increasing the van der Waals radii of the atoms with the van der Waals radius of the solvent molecule and to test the points for accessibility. We also provide error bounds as a function of the sample size. Experimental verification of the algorithms is carried out using an IBM SP-2.
We introduced the work on parallel problem solvers from physics and biology being developed by the research team at the State Key Laboratory of Software Engineering, Wuhan University. Results on parallel solvers inclu...
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We introduced the work on parallel problem solvers from physics and biology being developed by the research team at the State Key Laboratory of Software Engineering, Wuhan University. Results on parallel solvers include the following areas: Evolutionary algorithms based on imitating the evolution processes of nature for parallel problem solving, especially for parallel optimization and model-building; Asynchronous parallel algorithms based on domain decomposition which are inspired by physical analogies such as elastic relaxation process and annealing process, for scientific computations, especially for solving nonlinear mathematical physics problems. All these algorithms have the following common characteristics: inherent parallelism, self-adaptation and self-organization, because the basic ideas of these solvers are from imitating the natural evolutionary processes.
Chang et al. [parallel Comput. (1994) 233) introduced a parallel algorithm based on a shared memory SIMD architecture for the generation phase of the classic Horowitz and Sahni [J. ACM 21(2) (1974) 277] two-list seria...
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Chang et al. [parallel Comput. (1994) 233) introduced a parallel algorithm based on a shared memory SIMD architecture for the generation phase of the classic Horowitz and Sahni [J. ACM 21(2) (1974) 277] two-list serial algorithm for the knapsack problem. They claimed that their parallel generation phase could be accomplished in time O((n/8)(2)) and in space O(2(n/4)) with O(2(n/8)) processors. We prove that their results are not correct, i.e., that the suggested scheme time and space complexity should be bounded, instead, by O(n2(n/2)) and O(2(n/2)), respectively. These results also invalidate the performance analysis of the more recent Lou and Chang [parallel Comput. (1997) 1985] algorithm. (C) 2002 Elsevier Science B.V. All rights reserved.
Computing a distance map (distance transform) is an operation that converts a two-dimensional (2-D) image consisting of black and white pixels to an image where each pixel has a value or a pair of coordinates that rep...
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Computing a distance map (distance transform) is an operation that converts a two-dimensional (2-D) image consisting of black and white pixels to an image where each pixel has a value or a pair of coordinates that represents the distance to or location of the nearest black pixel. It is a basic operation in image processing and computer vision fields, and is used for expanding, shrinking, thinning, segmentation, clustering, computing shape, object reconstruction, etc. This paper examines the possibility of implementing, the problem of finding a distance map for an image efficiently using an optical bus. The computational model considered is the linear array with a reconfigurable pipelined bus system (LARPBS), which has been introduced recently based on current electronic and optical technologies. It is shown that the problem for an n x n, image can be implemented in O(log n log log n) bus cycles deterministically or in O(log n) bus cycles with high probability on an LARPBS with n(2) processors. By high probability, we mean a probability of greater than or equal to(1 - n(-alpha)) for any constant a greater than or equal to 1. We also show that the problem can be solved in O (log log n) bus cycles deterministically or in O(1) bus cycles with high probability on an LARPBS with n(3) processors. Scalability of the algorithms is also discussed briefly. The same problem can be solved using an LARPBS of P < n processors in O((n(2)/P) log n log log n) time deterministically or in O((n(2)/P) log n) time with high probability for any practical machine size of P. For processor arrays with practical sizes, a bus cycle is roughly the time of an arithmetic operation. Hence, the algorithm compares favorably to the best known parallel algorithms for the same problem in the literature.
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