共查询到20条相似文献,搜索用时 31 毫秒
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Duncan A. Buell 《The Ramanujan Journal》2012,29(1-3):31-49
Recent work of Bhargava has described higher composition laws that, among other things, subsume the composition of binary quadratic forms first given by Gauss. Bhargava??s presentation, however, does not provide an algorithmic method for compounding forms in the manner of Arndt??s classical composition method. In this paper, we will show, given two binary quadratic forms, how to find the Bhargava cube that represents their composition, and we will show that this can be done by what is essentially Arndt??s classical method. 相似文献
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作文评分误差控制是个难题,尤其在我国的高考中,由于考生众多,使问题更为尖锐。本文对作文评分误差的检测方法进行了研究,提出控制系统误差、随机误差的数学模型。并对其有效性给出定量分析。 相似文献
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Daowu Pei 《International Journal of Approximate Reasoning》2012,53(5):837-846
Fuzzy reasoning includes a number of important inference methods for addressing uncertainty. This line of fuzzy reasoning forms a common logical foundation in various fields, such as fuzzy logic control and artificial intelligence. The full implication triple I method (a method only based on implication, TI method for short) for fuzzy reasoning is proposed in 1999 to improve the popular CRI method (a hybrid method based on implication and composition). The current paper delves further into the TI method, and a sound logical foundation is set for the TI method based on the monoidal t-norm based logical system MTL. 相似文献
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In this paper a successive optimization method for solving inequality constrained optimization problems is introduced via a parametric monotone composition reformulation. The global optimal value of the original constrained optimization problem is shown to be the least root of the optimal value function of an auxiliary parametric optimization problem, thus can be found via a bisection method. The parametric optimization subproblem is formulated in such a way that it is a one-parameter problem and its value function is a monotone composition function with respect to the original objective function and the constraints. Various forms can be taken in the parametric optimization problem in accordance with a special structure of the original optimization problem, and in some cases, the parametric optimization problems are convex composite ones. Finally, the parametric monotone composite reformulation is applied to study local optimality. 相似文献
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本文研究了从上半平面的Hardy空间到Zygmund空间上的Volterra型算子和复合算子乘积的有界性问题.利用泛函分析和复分析的方法,获得了从上半平面的Hardy空间到Zygmund空间生成的Volterra型算子和复合算子的乘积有界性刻画,推广了S.Stevic关于从上半平面的Hardy空间到Zygmund空间上的复合算子有界性的结果. 相似文献
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《Numerical Functional Analysis & Optimization》2013,34(5-6):561-575
In this paper, we propose a method of calculating an element of B-differential, also an element of Clarke generalized Jacobian, for a vector-valued maximum function. This calculation is required in many existing numerical methods for the solution of nonsmooth equations and for the nonsmooth optimization. The generalization of our method to a vector-valued smooth composition of maximum functions is also discussed. Particularly, we propose a method of obtaining the set of B-differential for a vector-valued maximum of affine functions. 相似文献
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Qinghong Li Yongzhong Song 《高等学校计算数学学报(英文版)》2006,15(3):237-247
In this paper, we present an explicit one-step method for solving periodic initial value problems of second order ordinary differential equations. The method is P-stable, and of first algebraic order and high phase-lag order. To improve the algebraic order, we give a composition second order scheme with the proposed method and its adjoint. We report some numerical results to illustrate the efficiency of our methods. 相似文献
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本文用部分群化的方法,研究拓扑半群上概率测度的条件组合收敛性与SHIFT组合收敛性,得到了一些充分条件,并推广了一些组合收敛性结果. 相似文献
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An efficient algorithm for obtaining random bijective S-boxes based on chaotic maps and composition method is presented. The proposed method is based on compositions of S-boxes from a fixed starting set. The sequence of the indices of starting S-boxes used is obtained by using chaotic maps. The results of performance test show that the S-box presented in this paper has good cryptographic properties. The advantages of the proposed method are the low complexity and the possibility to achieve large key space. 相似文献
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The paper is devoted to the composition method of constructing families of irreducible polynomials over finite fields. 相似文献
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Web services have become increasingly popular in recent years, and they are especially suitable to the process of Web service composition, which is when several services are combined to create an application that accomplishes a more complex task. In recent years, significant research efforts have been made on developing approaches for performing Quality of Service -aware Web service composition. Evolutionary computing (EC) techniques have been widely used for solving this problem, since they allow for the quality of compositions to be optimised, meanwhile also ensuring that the solutions produced have the required functionality. Existing EC-based composition approaches perform constrained optimisation to produce solutions that meet those requirements, however these constraints may hinder the effectiveness of the search. To address this issue, a novel framework based on an indirect representation is proposed in this work. The core idea is to first generate candidate service compositions encoded as sequences of services. Then, a decoding scheme is developed to transform any sequence of services into a corresponding feasible service composition. Given a service sequence, the decoding scheme builds the workflow from scratch by iteratively adding the services to proper positions of the workflow in the order of the sequence. This is beneficial because it allows the optimisation to be carried out in an unconstrained way, later enforcing functionality constraints during the decoding process. A number of encoding methods and corresponding search operators, including the PSO, GA, and GP-based methods, are proposed and tested, with results showing that the quality of the solutions produced by the proposed indirect approach is higher than that of a baseline direct representation-based approach for twelve out of the thirteen datasets considered. In particular, the method using the variable-length sequence representation has the most efficient execution time, while the fixed-length sequence produces the highest quality solutions. 相似文献
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The essential norm of weighted composition operators on weightedBanach spaces of analytic functions is computed in terms ofthe weights and the inducing symbols. As a consequence the boundednessand compactness of these operators is characterized. As anotherconsequence the essential norm of composition operators on weightedBloch spaces is obtained and, consequently, the boundednessand compactness of composition operators on these spaces isalso characterized. Particular instances of weighted Bloch spacesare the Lipschitz spaces. The method used allows a unified treatmentof the problem of boundedness and compactness on these spaces. 相似文献
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This paper presents a backtracking method for constructing perfect hash functions from a given set of mapping functions. A hash indicator table is employed in the composition. By the nature of backtracking, the method can always find a perfect hash function when such a function does exist according to the composing scheme. Simulation results show that the probability of getting a perfect hash function by the backtracking method is much higher than by the single-pass and multipass methods previously proposed. 相似文献
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X-ray tomographic determination of the chemical composition and structure of an inhomogeneous medium
V. G. Nazarov 《Computational Mathematics and Mathematical Physics》2007,47(8):1358-1367
The chemical composition of an inhomogeneous body consisting of several homogeneous parts is determined by x-ray tomography. At the first stage, an indicator of inhomogeneities is used to determine the internal structure of the body. Next, under certain additional assumptions about the properties of the parts, a method is proposed for partial or complete determination of the chemical composition of each part as based on the results of the previous stage. Mathematically, the problem is reduced to solving the radiative transfer equation and systems of linear algebraic equations. Numerical experiments are performed via computer simulation. The numerical results are illustrated by graphs and tomograms. 相似文献
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Nina Zorboska 《Proceedings of the American Mathematical Society》1998,126(7):2013-2023
We characterize bounded and compact composition operators on weighted Dirichlet spaces. The method involves integral averages of the determining function for the operator, and the connection between composition operators on Dirichlet spaces and Toeplitz operators on Bergman spaces. We also present several examples and counter-examples that point out the borderlines of the result and its connections to other themes.
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本文给出了求解非线性方程的一种新的改进方法.利用Newton法和Heron平均,将新改进方法与其它一些迭代法作比较.数值结果表明该方法具有一定的实用价值. 相似文献
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本文研究H∞和Bergman空间之间加权复合算子uCφ的有界性或紧性,利用泛函分析及复分析的方法,获得了uCφ是有界算子或紧算子的充要条件在H∞和Bergman空间之间的范数估计,推广了各类解析函数空间上加权复合算子的相应理论. 相似文献
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This paper presents a new trust region algorithm for solving a class of composite nonsmooth optimizations. It is distinguished by the fact that this method does not enforce strict monotonicity of the objective function values at successive iterates and that this method extends the existing results for this type of nonlinear optimization with smooth, or piecewise smooth, or convex objective functions or their composition. It is proved that this algorithm is globally convergent under certain conditions. Finally, some numerical results for several optimization problems are reported which show that the nonmonotonic trust region method is competitive with the usual trust region method. 相似文献