共查询到20条相似文献,搜索用时 62 毫秒
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针对信息系统属性约简问题,通过借助粒关系包含度矩阵这一中间工具,给出一种决策表属性启发式约简算法.首先,计算决策表中条件属性与决策属性之间的粒关系包含度矩阵;然后,将粒关系包含度矩阵中隐含的信息L_B作为启发式算子对决策表进行属性约简;最后,删除冗余属性并设置终止条件,实现决策表的属性约简.通过实例验证了该算法的有效性. 相似文献
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基于粗糙集与层次分析法的组合预测方法 总被引:3,自引:0,他引:3
本文在改进的属性约简启发式算法 ,即应用加权平均的属性重要度对属性进行约简的基础上 ,将粗糙集理论和层次分析相结合 ,给出了一种全新的组合预测方法 . 相似文献
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在模糊目标信息系统决策约简和可辨识矩阵定义的基础上,讨论了可辨识矩阵的性质以及与决策约简集之间的关系.同时定义一种新的属性重要度,并将此作为启发式信息,设计了一种模糊目标决策信息系统最小决策约简算法,通过实例验证该算法简捷、有效. 相似文献
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模糊差别矩阵属性约简是一种广泛使用的模糊粗糙集属性约简方法。然而已有方法大多采用启发式贪婪策略,属性约简率低且约简质量差。本文结合Markov Blanket概念,提出基于模糊差别矩阵的属性约简算法。首先,为了避免约简选择过多属性的问题,提出了利用Markov Blanket性质的迭代后向删除属性约简算法,可以有效删除低频率的相对冗余属性。其次,提出了一种基于Markov Blanket的双向搜索启发式属性约简算法,通过迭代前向添加高频属性和后向删除低频率策略来提升属性约简计算效率。在UCI数据集上实验表明,相比于其他模糊差别矩阵算法,所提出的算法能得到更优的约简结果。 相似文献
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ZHENG ShiJun 《分析论及其应用》2004,20(3)
Schr(o)dinger operator is a central subject in the mathematical study of quantum mechanics.Consider the Schrodinger operator H = -△ V on R, where △ = d2/dx2 and the potential function V is real valued. In Fourier analysis, it is well-known that a square integrable function admits an expansion with exponentials as eigenfunctions of -△. A natural conjecture is that an L2 function admits a similar expansion in terms of "eigenfunctions" of H, a perturbation of the Laplacian (see [7], Ch. Ⅺ and the notes), under certain condition on V. 相似文献
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《高校应用数学学报(英文版)》2014,29(4)
正Applied Mathematics-A Journal of Chinese Universities,Series B(Appl.Math.J.Chinese Univ.,Ser.B)is a comprehensive applied mathematics journal jointly sponsored by Zhejiang University,China Society for Industrial and Applied Mathematics,and Springer-Verlag.It is a quarterly journal with 相似文献
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《数学研究及应用》2014,(6)
正Journal overview:Journal of Mathematical Research with Applications(JMRA),formerly Journal of Mathematical Research and Exposition(JMRE)created in 1981,one of the transactions of China Society for Industrial and Applied Mathematics,is a home for original research papers of the highest quality in all areas of mathematics with applications.The target audience comprises:pure and applied mathematicians,graduate students in broad fields of sciences and technology,scientists and engineers interested in mathematics. 相似文献
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A cumulative-capacitated transportation problem is studied. The supply nodes and demand nodes are each chains. Shipments from a supply node to a demand node are possible only if the pair lies in a sublattice, or equivalently, in a staircase disjoint union of rectangles, of the product of the two chains. There are (lattice) superadditive upper bounds on the cumulative flows in all leading subrectangles of each rectangle. It is shown that there is a greatest cumulative flow formed by the natural generalization of the South-West Corner Rule that respects cumulative-flow capacities; it has maximum reward when the rewards are (lattice) superadditive; it is integer if the supplies, demands and capacities are integer; and it can be calculated myopically in linear time. The result is specialized to earlier work of Hoeffding (1940), Fréchet (1951), Lorentz (1953), Hoffman (1963) and Barnes and Hoffman (1985). Applications are given to extreme constrained bivariate distributions, optimal distribution with limited one-way product substitution and, generalizing results of Derman and Klein (1958), optimal sales with age-dependent rewards and capacities.To our friend, Philip Wolfe, with admiration and affection, on the occasion of his 65th birthday.Research was supported respectively by the IBM T.J. Watson and IBM Almaden Research Centers and is a minor revision of the IBM Research Report [6]. 相似文献
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Emmanuel Blanc 《Commentarii Mathematici Helvetici》2003,78(4):845-864
Résumé On décrit toutes les feuilles des laminations minimales dont
un ensemble résiduel de feuilles ont 2 bouts.
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H. Mohebi A. M. Rubinov 《分析论及其应用》2006,22(1):20-40
We develop a theory of downward sets for a class of normed ordered spaces. We study best approximation in a normed ordered space X by elements of downward sets, and give necessary and sufficient conditions for any element of best approximation by a closed downward subset of X. We also characterize strictly downward subsets of X, and prove that a downward subset of X is strictly downward if and only if each its boundary point is Chebyshev. The results obtained are used for examination of some Chebyshev pairs (W,x), where ∈ X and W is a closed downward subset of X 相似文献
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Tao Guiping 《分析论及其应用》2005,21(1):73-89
In this paper, the author establishes the boundedness of multilinear operators on weighted Herz spaces and Herz-type Hardy spaces. The author also obtains their weak estimates on endpoints. As a special case, the conclusions may lead to the weighted estimates for multilinear Calderon-Zygmund operators. 相似文献
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In this paper we present a generalized quantitative version of a result due to M. Revers concerning the exact convergence rate at zero of Lagrange interpolation polynomial to f(x) = |x|α with on equally spaced nodes in [-1, 1]. 相似文献