共查询到20条相似文献,搜索用时 15 毫秒
1.
为了抵抗差分密码攻击,密码算法设计希望使用低差分函数.完全非线性函数(perfect nonli-near function, PN函数)、几乎完全非线性函数(almost perfect nonlinear function, APN函数)和4差分置换(differentially 4-uniform permutition)是最重要的几类低差分函数(low differential uniformity function).总结了近年来在PN函数、APN函数和4差分置换等低差分函数研究方面的主要进展.1)回顾了PN函数与半域等数学对象的联系,梳理了PN函数的已有构造以及伪平面函数的构造;2)分析了APN函数的性质与判定,总结了APN函数的已有构造以及它们之间等价性分析方面的结果;3)对于4差分置换,总结了其已有构造及其等价性分析结果;4)介绍了低差分函数在实际密码算法设计中的应用;5)对低差分函数的下一步研究进行了展望. 相似文献
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Hausdorff continuous (H-continuous) functions are special interval-valued functions which are commonly used in practice, e.g. histograms are such functions. However, in order to avoid arithmetic operations with intervals, such functions are traditionally treated by means of corresponding semi-continuous functions, which are real-valued functions. One difficulty in using H-continuous functions is that, if we add two H-continuous functions that have interval values at same argument using point-wise interval arithmetic, then we may obtain as a result an interval function which is not H-continuous. In this work we define addition so that the set of H-continuous functions is closed under this operation. Moreover, the set of H-continuous functions is turned into a linear space. It has been also proved that this space is the largest linear space of interval functions. These results make H-continuous functions an attractive tool in real analysis and provides a bridge between real and interval analysis. 相似文献
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基于研究布尔函数在子空间的限制,得到关于Gbent函数的一个充分必要条件。给出了两类简单的正则的Gbent函数。在此基础上,通过间接构造Bent函数的方法,利用已知的Gbent函数构造出了更多的Gbent函数。 相似文献
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Ang Zhang Ixchel G. Ramirez-Alpizar Kévin Giraud Esclasse Olivier Stasse Kensuke Harada 《Advanced Robotics》2019,33(9):454-468
This paper proposes a real-time walking pattern generator (WPG) based on model predictive control (MPC). Since reducing the calculation time is a crucial problem in real-time WPG, we consider introducing basis functions to reduce the number of control input. The control inputs in the MPC are described by a series of basis functions. Compared with the standard discrete-time MPC formulation, the approach with basis functions requires fewer optimization variables at the cost of decreasing precision. In order to find an appropriate trade-off, two basis functions named Laguerre functions and Haar functions, are tested in this paper. MPC with Laguerre functions decreases more computational load while MPC with Haar functions offers a more accurate solution. The approach is not restricted to Laguerre functions or Haar functions, users can select their own basis functions for different applications and preferences. 相似文献
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《国际计算机数学杂志》2012,89(5):943-949
In this paper, we define a large class of almost balanced Boolean functions called nearly bent functions. These functions lie at large Hamming distance to all affine functions and preserve a high level of algebraic degree. Then a construction of nearly bent functions is described. It is shown that the constructed functions have good global avalanche characteristic properties. In the concluding remarks, we show that nearly bent functions have good stability. 相似文献
6.
基于AHP模型的政府系统职能评价方法的研究 总被引:1,自引:0,他引:1
政府人力资源系统与政府职能密切相关,研究政府人力资源必须从政府职能的视角对政府系统的要素与职能的关系进行分析.在政府系统的环境适应性概念模型的基础之上,通过对政府系统的政治职能、经济职能、社会职能、文化职能的分析,研究了政府系统要素与职能、规模关系,明确了政府系统的目标是政府系统内部结构分析的出发点,是政府系统目的的具体化的特征,确定了政府系统的目标集,构建了政府职能评价的递级层次结构模型,并通过AHP方法,构建了政府系统职能评价模型. 相似文献
7.
1 Introduction Copy theory is a kind of signal generation technology, built on the research of Walsh function. The main content of the copy theory includes generating non-sine orthogonal functions, utilizing shift and symmetric copy methods and control in… 相似文献
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互补对称布尔函数是一类特殊的对称布尔函数。在所有代数免疫最优的对称布尔函数中,有相当的比例均属此类函数。特别是当变元数量为2m元时,有2/3比例的代数免疫最优对称布尔函数都是互补对称布尔函数。通过布尔函数非线性度、Walsh谱和Krawtchouk多项式间的关系,计算出互补对称布尔函数的非线性度。结果表明,任意n元互补对称布尔函数的非线性度为2n-1-1/2[nn/2] 相似文献
10.
函数是C语言学习的难点和重点,通过分析函数的结构,将函数编写中难以确定的问题进行分解、细化。按照返回值的个数将函数分为:无返回值函数、单反回值函数、多返回值函数三种类型。对这三种类型函数的设计方法分别举例分析和说明,详细阐述了函数编写的具体过程。 相似文献
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Inspired by the Zadeh approach to fuzzy connectives in fuzzy set theory and by some applications, we introduce and study set-based extended functions, and in particular, set-based extended aggregation functions. These functions reflect neither reordering nor repetition of input values, and, linking different arities, they introduce serious constraints for extended functions. A complete characterization of set-based extended (aggregation) functions is given, and some constructions of such functions are also proposed, including several examples. 相似文献
13.
光滑函数在支持向量机中起着重要作用,熊金志等人用插值函数的方法导出了一个递推公式,得到了一类新的光滑函数,解决了一个关于是否存在以及如何寻求性能更好的光滑函数的问题。然而其中五阶光滑的多项式函数还未进行性能分析。首先推导出了该光滑函数的表达式,然后分析了它的若干性能。结果表明,该光滑函数具有良好的逼近性能,其逼近精度高于以往的光滑函数。 相似文献
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光滑函数在光滑支持向量机的理论中起着重要作用.1996年Chen等人提出一个支持向量机的光滑函数——Sigmoid函数的积分函数,并解决了该光滑函数的误差问题.2005~2009年,袁玉波、熊金志和刘叶青等人相继提出支持向量机的无穷多个多项式光滑函数和多项式光滑的支持向量机模型,但都未解决这类多项式光滑函数的误差函数问题.为此,用 Newton-Hermite 插值方法研究该问题.研究结果表明:1)用 Newton-Hermite 插值方法可计算这类光滑函数的误差函数,并给出了具体算法;2)这类误差函数有无穷多个,可用一个一般形式表示,并得到了这个一般形式;3)这类误差函数具有许多重要性质,并给出了严格证明.解决了支持向量机无穷多个多项式光滑函数的误差函数及其性质问题,建立了这类多项式光滑函数的误差理论,为研究支持向量机的光滑理论提供了基本的理论支持. 相似文献
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Stefano Battilotti 《Asian journal of control》2012,14(4):924-935
In this paper a generalized class of filtered Lyapunov functions is introduced, which are Lyapunov functions with time‐varying parameters satisfying certain differential equations. Filtered Lyapunov functions have the same stability properties as Lyapunov functions. Tools are given for designing composite filtered Lyapunov functions for cascaded systems. These functions are used to design globally stabilizing dynamic feedback laws for block‐feedforward systems with stabilizable linear approximation. 相似文献
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《Computer Aided Geometric Design》2014,31(9):674-688
In this paper two kinds of bivariate S-λ basis functions, tensor product S-λ basis functions and triangular S-λ basis functions, are constructed by means of the technique of generating functions and transformation factors. These two kinds of bivariate S-λ basis functions have lots of important properties, such as non-negativity, partition of unity, linear independence and so on. The framework of the tensor product S-λ basis functions provides a unified scheme for dealing with several kinds of tensor product basis functions, such as the tensor product Bernstein basis functions, the tensor product Poisson basis functions and some other new tensor product basis functions. The framework of the triangular S-λ surface basis functions includes the triangular Bernstein basis functions, the rational triangular Bernstein basis functions and some other new triangular basis functions. Moreover, the corresponding two kinds of S-λ surfaces are constructed by means of these two kinds of bivariate basis functions, respectively. These two kinds of S-λ surface patches have the important properties of surface modeling, such as affine invariance, convex hull property and so on. 相似文献
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CHAO-KUANG CHEN SHIN-GIA KUO CHING-YU YANG 《International journal of systems science》2013,44(5):799-817
There are many functions having the property of orthogonality. Among them are Walsh functions, block-pulse functions, Chebyshev functions and Legendre functions. Recently, many scholars and researchers made new approaches to solving variational problems via orthogonal functions. This paper suggests a more simple and powerful orthogonal method—the Fourier series operational matrix for integration—which is derived and used to solve a variational problem. 相似文献
18.
Chia-Chien Huang 《Computer Physics Communications》2009,180(3):375-2505
A new approach based on spectral method with efficient basis functions is proposed in the paper to simulate semiconductor nanodevice by solving the Schrödinger equation. The computational domain is partitioned at heterojunctions into a number of subdomains. The envelope functions in subdomains are expanded by various efficient basis functions and then patched by the BenDaniel-Duke boundary conditions to preserve exponential order of accuracy. Importantly, the consideration to choose the basis functions depends on the oscillatory characteristics of envelope functions. Three kinds of basis functions including prolate spheroidal wave functions, Chebyshev polynomials, and Laguerre-Gaussian functions are used according to the mathematical features in this work. In addition, the determinations of optimum values of scaling factor in Laguerre-Gaussian functions and bandwidth parameter in prolate spheroidal wave functions are also discussed in detail. Several quantum well examples are simulated to validate the effectiveness of the present scheme. The relative errors of energy levels achieve the order of 10−12 requiring merely a few grid points. 相似文献
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Since most biological systems are developmental and dynamic, time-course gene expression profiles provide an important characterization of gene functions. Assigning functions for genes with unknown functions based on time-course gene expressions is an important task in functional genomics. Recently, various methods have been proposed for the classification of gene functions based on time-course gene expression data. In this paper, we consider the classification of gene functions from functional data analysis viewpoint, where a functional support vector machine is adopted. The functional support vector machine can model temporal effects of time-course gene expression data by incorporating the coefficients as well as the basis matrix obtained from a finite expansion of gene expressions on a set of basis functions. We apply the functional support vector machine to both real microarray and simulated data. Our results indicate that the functional support vector machine is effective in discriminating gene functions of time-course gene expressions with predefined functions. The method also provides valuable functional information about interactions between genes and allows the assignment of new functions to genes with unknown functions. 相似文献
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《Computers & Mathematics with Applications》2000,39(9-10):173-199
Following sine-cosine functions, sawtooth wave, square wave, triangular wave, and trapezoidal wave become new easily-generated periodic functions. Can a signal be considered to be a superposition of easily-generated functions with different frequencies? In order to answer this question, we generalize Fourier analysis to easily-generated function analysis including easily-generated functions series, easily-generated function transformation, and discrete transformation for easily-generated functions. The results in this paper make it possible to represent a signal by use of easily-generated functions. A lot of techniques based on sine-cosine functions can be translated into techniques based on easily-generated functions. Because Dirichlet multiplication in number theory plays a basic role in easily-generated function analysis, we briefly introduce this concept and present a related formula. The main contents of this paper include Dirichlet multiplication and a related formula, relations between basic waveforms in electronics, easily-generated function series, easily-generated function transformation, discrete transformation for easily-generated functions, and techniques of easily-generated function analysis. 相似文献