共查询到19条相似文献,搜索用时 156 毫秒
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本通过用对数函数对原始数据列{x^(0)(k)}进行预测,又提出用幂函数对原始数据列进行变换,对提高离散数据的光滑度。在此基础上再将对数变换与幂函数交换两结合起来,产生一种新的变换——“对数函数—幂函数变换”,达到了进一步增加数据的光滑度,提高预测精度的目的。 相似文献
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针对原始数据序列光滑度不足的情况,提出了一种新的数据变换方法,以提高原始数据序列的光滑度.给出方法的理论证明,并与其它数据变换方法进行了对比.将变换方法应用于GM(1,1)模型,结果显示,通过调节参数的值,变换能够提高GM(1,1)模型的计算精度.最后的实例说明了该方法的实用性和有效性. 相似文献
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提出了反余弦函数变换方法,证明了这种变换是级比压缩变换,能够提高序列光滑度,可以保持序列凹凸性,不会增大还原误差,满足数据变换的构造准则.通过具体算例表明,基于反余弦函数变换的GM(1,1)模型的预测精度优于传统GM(1,1)模型和基于幂函数变换的GM(1,1)模型,说明了该变换的有效性. 相似文献
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基于灰色系统理论扩展了GM(1,1)模型建模方法.给出了一些既改善原始数据列的光滑度,又减少还原误差的变换函数构造条件.首次将灰色动态模型结合变换函数应用于堆浸过程浸出率的预测.结果表明:该方法预测精度高,为实现浸出动力学未来行为的预测和控制提供了一种新的方法. 相似文献
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大量的事例表明,当我们用函数模型去描述变化现象时,指数函数、对数函数、幂函数扮演着重要的角色,是三类重要的基本函数. 相似文献
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基于拓广的GM(1,1)的土地利用变化情景研究 总被引:1,自引:0,他引:1
根据土地利用类型面积变化的特点和GM的理论缺陷,对GM进行了修正和拓广,即采用“幂函数—对数函数”和“指数函数”对原始数列进行离散化处理,将一次累加后的数据列作为已知条件,这种方法对提高预测精度提供了新的途径.最后结合预测结果对研究区土地资源的合理规划与利用提出了建议. 相似文献
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先简介幂、指、对等函数图像共点性结论如下:(1)幂函数y=x^n(x〉0,n∈Q)图像都通过点(1,1);(2)指数函数y=a^x(a〉1,a≠1)图像都通过点(0,1);(3)对数函数y=logax(a〉0,a≠1,x〉0)图像都通过点(1,0). 相似文献
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对灰色模型做了进一步的研究,拓广了灰色模型,建立了一个新的、预测精度较高的新灰色预测模型——"对数函数——幂函数变换"模型,并利用此模型对我国博士后研究人员增量做出精度较高的灰色预测. 相似文献
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L. D. Popov 《Proceedings of the Steklov Institute of Mathematics》2008,263(2):108-119
A novel modification of the logarithmic barrier function method is introduced for solving problems of linear and convex programming. The modification is based on a parametric shifting of the constraints of the original problem, similarly to what was done in the method of Wierzbicki-Hestenes-Powell multipliers for the usual quadratic penalty function (this method is also known as the method of modified Lagrange functions). The new method is described, its convergence is proved, and results of numerical experiments are given. 相似文献
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We present a new method for proving non-holonomicity of sequences, which is based on results about the number of zeros of
elementary and of analytic functions. Our approach is applicable to sequences that are defined as the values of an elementary
function at positive integral arguments. We generalize several recent results, e.g., non-holonomicity of the logarithmic sequence
is extended to rational functions involving log n. Moreover, we show that the sequence that arises from evaluating the Riemann zeta function at an increasing integer sequence
with bounded gap lengths is not holonomic.
Martin Klazar: ITI is supported as project 1M0021620808 by Ministry of Education of the Czech Republic. 相似文献
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Two general methods for establishing the logarithmic behavior of recursively defined sequences of real numbers are presented. One is the interlacing method, and the other one is based on calculus. Both methods are used to prove logarithmic behavior of some combinatorially relevant sequences, such as Motzkin and Schröder numbers, sequences of values of some classic orthogonal polynomials and many others. The calculus method extends also to numbers indexed by two or more parameters. 相似文献
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Alexander Nickolaevich Kholodov 《Acta Appl Math》1990,19(1):55-76
D. E. Loeb and G.-C. Rota, using the operator of differentiation D, constructed the logarithmic algebra that is the generalization of the algebra of formal Laurent series. They also introduced Appell graded logarithmic sequences and binomial (basic) graded logarithmic sequences as sequences of elements of the logarithmic algebra and extended the main results of the classical umbral calculus on such sequences. We construct an algebra by an operator d that is defined by the formula (1.1). This algebra is an analog of the logarithmic algebra. Then we define sequences analogous to Boas-Buck polynomial sequences and extend the main results of the nonclassical umbral calculus on such sequences. The basic logarithmic algebra constructed by the operator of q-differentiation is considered. The analog of the q-Stirling formula is obtained. 相似文献
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This paper deals with regularized penalty-barrier methods for convex programming problems. In the spirit of an iterative proximal regularization approach, an interior-point method is constructed, in which at each step a strongly convex function has to be minimized and the prox-term can be scaled by a variable scaling factor. The convergence of the method is studied for an axiomatically given class of barrier functions. According to the results, a wide class of barrier functions (in particular, logarithmic and exponential functions) can be applied to design special algorithms. For the method with a logarithmic barrier, the rate of convergence is investigated and assumptions that ensure linear convergence are given. 相似文献
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The aim of this paper is to present an algorithm for finding a saddle point to the constrained minimax problem. The initial problem is transformed into an equivalent equality constrained problem, and then the interior point approach is used. To satisfy the original inequality constraints a logarithmic barrier function is used and special care is given to step size parameter to keep the variables within permitted boundaries. Numerical results illustrating the method are given. 相似文献
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Rita Giuliano Claudio Macci Barbara Pacchiarotti 《Journal of Mathematical Analysis and Applications》2014
In this paper we study some sequences of weighted means of continuous real valued Gaussian processes. More precisely we consider suitable generalizations of both arithmetic and logarithmic means of a Gaussian process with covariance function which satisfies either an exponential decay condition or a power decay condition. Our aim is to provide limits of variances of functionals of such weighted means which allow the application of some large deviation results in the literature. 相似文献
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A Combined Homotopy Infeasible Interior-Point Method for Convex Nonlinear Programming 总被引:2,自引:0,他引:2
In this paper, on the basis of the logarithmic barrier function and KKT conditions , we propose a combined homotopy infeasible interior-point method (CHIIP) for convex nonlinear programming problems. For any convex nonlinear programming, without strict convexity for the logarithmic barrier function, we get different solutions of the convex programming in different cases by CHIIP method. 相似文献