共查询到19条相似文献,搜索用时 171 毫秒
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本文对多输出布尔函数的第二类非线性度进行研究,该定义是衡量抵抗最佳多输出仿射逼近攻击性能的一项重要准则.利用多输出布尔函数的Walsh变换,我们给出第二类非线性度的一种表达式,并在此基础上得到第二类非线性度的一个上界.进一步地,我们给出了当第一类非线性度达到最优时,其第二类非线性度的一个界.此外,本文还给出任意多输出布尔函数与所有多输出线性函数之间距离的均值. 相似文献
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差分跳频是一种新的扩展频谱通信技术.在介绍差分跳频基本原理的基础上,将差分跳频的频率跳变过程建模成齐次马尔可夫链.分析了G函数的功能,重点讨论了差分跳频码性能的检验方法,包括不可约性、频隙滞留、均匀性和随机性检验,其中频隙滞留是首次提出应用于差分跳频码性能的检验.这些检验方法对于差分跳频G函数的设计具有一定的指导意义. 相似文献
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给出了二阶强迫非线性时滞差分方程△^2xn anf(xn-k)=gn的所有解弱振动的一个充要条件。 相似文献
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为了探索Gd2Ti1.3Zr0.7O7烧绿石快速固化高放废物中锕系核素的方法,采用Sm模拟三价锕系核素,以氧化铜为氧化剂、钛粉为还原剂,氧化钆、氧化钐和二氧化锆为原料,利用自蔓延高温结合快速加压合成技术制备掺钐烧绿石陶瓷固化体,分别采用X射线衍射仪(XRD)、场发射扫描电镜(FESEM)、能谱仪(EDS)、电感耦合等离子体发射光谱-质谱(ICP-MS)和维氏硬度计研究样品的物相、微观组织形貌、元素分布、化学稳定性和力学性能。结果表明:自蔓延高温快速加压合成法在极短的时间(5 min)内合成完全固溶的Gd2-xSmxTi1.3Zr0.7O7(0≤x≤0.2)烧绿石陶瓷固化体,烧绿石陶瓷固化体(x=0.2)的相对密度达92.8%,具有优异的化学稳定性;浸出时间为42 d时,Gd和Sm的归一化浸出率分别为2.23×10-5 g·m-2·d-1、1.57×10-5 g·m-2·d-1。 相似文献
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一类二阶非线性差分方程的振动性质 总被引:2,自引:0,他引:2
从解的渐近状态着手,将所述方程的所有非平凡解分成互不相交的四类,应用分类讨论方法和分析方法,讨论了一类广泛的二阶非线性差分方程解的振动性质,建立了两个新的振动性定理,推广并改进了已有文献中的相关结果。 相似文献
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Xiyong Zhang Hua Guo 《Applicable Algebra in Engineering, Communication and Computing》2008,19(4):293-309
Perfect nonlinear functions are of importance in cryptography. By using Galois ring, relative trace and investigating the
character values of corresponding relative difference sets, we present a construction of perfect nonlinear functions from
to , where m′ is a divisor of 2m, and a construction of perfect nonlinear functions from to where 2m is possibly larger than the largest divisor of n. Meanwhile we prove that there exists a perfect nonlinear function from to if and only if p = 2, and there doesn’t exist a perfect nonlinear function from to if m > n and l(l is odd) is self-conjugate modulo 2
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(k ≥ 1).
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Ziran Tu Dabin Zheng Xiangyong Zeng Lei Hu 《Applicable Algebra in Engineering, Communication and Computing》2011,22(5-6):359-366
Are there other Boolean functions having two distinct Walsh coefficients except affine Boolean functions and maximal nonlinear (i.e. bent) Boolean functions? This paper proves that all Boolean functions with exactly two distinct Walsh coefficients are just the two known classes of affine and bent Boolean functions and the Boolean functions obtained by modifying the value of affine or bent Boolean functions at x?=?0. 相似文献
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After Google reported its realization of quantum supremacy, Solving the classical problems with quantum computing is becoming a valuable research topic. Switching function minimization is an important problem in Electronic Design Automation (EDA) and logic synthesis, most of the solutions are based on heuristic algorithms with a classical computer, it is a good practice to solve this problem with a quantum processer. In this paper, we introduce a new hybrid classic quantum algorithm using Grover’s algorithm and symmetric functions to minimize small Disjoint Sum of Product (DSOP) and Sum of Product (SOP) for Boolean switching functions. Our method is based on graph partitions for arbitrary graphs to regular graphs, which can be solved by a Grover-based quantum searching algorithm we proposed. The Oracle for this quantum algorithm is built from Boolean symmetric functions and implemented with Lattice diagrams. It is shown analytically and verified by simulations on a quantum simulator that our methods can find all solutions to these problems. 相似文献
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In this paper, an effective numerical method for solving nonlinear Volterra partial integro-differential equations is proposed. These equations include the partial differentiations of an unknown function and the integral term containing the unknown function which is the “memory” of problem. This method is based on radial basis functions (RBFs) and finite difference method (FDM) which provide the approximate solution. These techniques play the important role to reduce a nonlinear partial integro-differential equation to a linear system of equations. Some illustrative examples are shown to describe the method. Numerical examples confirm the validity and efficiency of the presented method. 相似文献
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《Virtual and Physical Prototyping》2013,8(3):149-163
Heterogeneous structures represent an important new frontier for twenty-first-century engineering. In this paper, based on the shape function in the finite element method, a morphology-controllable modelling approach for constructing tissue engineering (TE) bone scaffold with various irregular pores is presented. The modelling approach consists of both irregular element modelling and the whole bone scaffold modelling. Accepting the elements’ information after all-hex mesh generation as inputs, the basic pore-making element can be mapped into various irregular elements based on the shape function. In the bone scaffold modelling, the Boolean difference between the contour model of the solid entity and the pore model which can be constructed by the Boolean operation union would generate a porous bone scaffold model. Compared to the stochastic geometry method and the discrete element packing method, the bone scaffold model obtained in this paper has a continuous, smooth contour and various irregular pores. Moreover, a decrease in computational complexity is achieved in this paper. 相似文献
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采用相位差校正法进行频谱校正,对幅值进行校正需要依赖于窗函数的谱函数。而实际上很多窗函数都十分复杂,其谱函数的解析表达式难以取得。该文提出基于相位差法取得频率修正量后,可以将原加窗序列乘以一个由频率修正量产生的复数序列,相当于进行一个小的频移,产生一个新的序列。新序列的信号频率正好对准离散频谱上的某一根谱线,不会产生泄漏。因此在幅值校正时不需要依赖窗函数的谱函数,通用性好。仿真研究和应用实例表明,采用该文提出的方法,选择合适的窗函数,即使是密集分布的频谱,也可以达到理想的校正精度 相似文献
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对称布尔函数的代数免疫性 总被引:2,自引:0,他引:2
在流密码和分组密码的加密体制中,需要构作具有各种密码学性质的布尔函数,用来作为密钥,以抵抗已有的各种有效攻击方法。近年来,人们提出了代数攻击方法,为了抵抗这种攻击方式,构作代数免疫度很大的布尔函数,成为近五年来信息安全领域一个研究热点。本文综述布尔函数代数免疫性方面的重要问题和主要进展,其中包括中国学者在对称布尔函数代数免疫性的研究成果。 相似文献