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1.
本文证明了一介定性证明的余式方法对于线性策略是完备的,而对于语义策略和锁策略,在例题演算中是完备的,在一阶谓词演算法,对于一种较弱形式的语义策略和锁策略,提完备的。  相似文献   

2.
针对密码学中布尔函数的代数免疫性和构造需求,通过选取适当次数的布尔函数,利用布尔函数的级联性质,提出了一种提高布尔函数代数免疫阶的递归构造法;同时证明了该构造法中所构造的布尔函数比原布尔函数的代数免疫阶高,利用该方法可以递归构造具有最优代数免疫阶平衡布尔函数,最后给出了一个具体实例。  相似文献   

3.
代数免疫阶最高的Boole函数的构造和计数   总被引:2,自引:0,他引:2  
代数免疫阶是针对代数攻击而提出的新的密码准则。为了抵抗代数攻击,流密码中所使用的Boole函数应该具有高代数免疫阶。文中运用替换掉Dalai所构造的代数免疫对称Boole函数支撑集中一些点的方法构造了大量具有最高代数免疫阶的Boole函数,并给出了所构造函数的计数。特别地,对于某些代数次数低于n/2的多项式p(x),构造了代数标准形中单项式系数都不小于n/2的q(x)使得p(x)+q(x)具有最高代数免疫阶。  相似文献   

4.
组合险象逻辑余式判据   总被引:7,自引:1,他引:6  
童永承 《计算机学报》1994,17(6):429-434
本文给出了逻辑函数余式的定义,建立了简单逻辑函数余式和复合逻辑函数余式,并得到一系列逻辑冒险,0型功能冒险,1型功能冒险的判定定理及确定各类险象和其转化条件,为无险象组合电路设计及最终解决组合险象问题奠定了坚实的基础。  相似文献   

5.
代数攻击是近年来兴起的一种有效而有趣的攻击方法[2]之一,被成功地应用于一些基于LFSR的流密码系统中,对流密码体制产生了巨大影响,众多密码工作者在代数攻击中求解多变元超定方程组求解、零化子的构造等方面都做了比较有效的研究。为了抵抗代数攻击,Meier等人[4]引入度量布尔函数安全性的新指标——代数免疫。代数免疫的提出给密码函数的分析和设计提出了新的课题[5]。该文介绍了一种具有最高代数免疫阶的非对称布尔函数的构造,这类构造最初由密码爱好者在2005年快速软体加密国际研讨会上做了简单介绍,但没有进行深入分析。该文研究证明了该类函数具有n个变量的时候函数具有最大可能的代数免疫阶为,是一类具有最高可能代数免疫阶的布尔函数。该文的最后研究了这类函数的代数阶、汉明重量,非线性度、Walsh谱等密码学特性。  相似文献   

6.
利用谓词/变迁网证明的一阶谓词逻辑命题   总被引:1,自引:0,他引:1       下载免费PDF全文
方欢  印玉兰  徐誉尹 《计算机工程》2006,32(23):191-192
研究了证明一般的一阶谓词逻辑命题的方法,根据网逻辑的思想,利用谓词/变迁网对一般形式的一阶谓词逻辑命题进行了图形表示,提出了2种一阶谓词逻辑命题的证明方法:图形证明法和矩阵证明法。举出一个实际的例子来说明证明思路。  相似文献   

7.
何良生 《计算机学报》2006,29(9):1579-1583
研究了布尔函数的线性结构点个数与其代数免疫阶之间的关系,得到了具有1型线性结构布尔函数的代数免疫阶完全取决于函数零化子代数次数的结论.从线性结构点的角度构造了一类具有最高代数免疫阶的布尔函数,并给出了”为偶数时,函数的Walsh循环谱和自相关函数的取值特点.  相似文献   

8.
多值逻辑定理机器证明的代数方法   总被引:2,自引:1,他引:1  
吴尽昭 《计算机学报》1996,19(10):773-779
由给定的多值逻辑系统中的一组公式ψ1,、…,ψm,ψ出发,构造了一组表理数域睛的多项式PS,全副独ψ是ψ1,…,ψm的逻辑结论,当且仅当PS定义的代数簇为空集,当且仅当PS生成的理想是平凡理想。从而,利用特征列方法和Groebner基方法,给出了判定ψ是否ψ1,…,ψm逻辑结论的两种算法。  相似文献   

9.
提出一种二阶级联构造方法,通过选择恰当的参数s,使每次级联增加2个变元的同时代数免疫阶增加1、代数次数增加1。该方法在保持布尔函数弹性的同时能有效提高非线性度。在此基础上设计一类非线性度高于已知构造方法的代数免疫最优布尔函数以及一类非线性度好且满足一阶弹性的代数免疫至少次优的布尔函数,并利用二阶级联迭代构造密码学性质好的布尔函数。  相似文献   

10.
通常方法构造的高阶非完整系统的运动微分方程不仅没有完整系统的辛几何结构和Lie代数结构,而且也不具备完整系统的自伴随性质.本文利用降阶方法,将高阶非完整系统变换为一阶动力学系统,并运用Cauchy-Kowalevski定理对其自伴随化,得到一种新的一阶动力学方程组-广义Birkhoff表示,这将为研究高阶非完整系统的若干动力学问题、几何结构、代数结构、几何数值积分以及工程应用提供了一个新的方法.  相似文献   

11.
针对混沌时间序列预测中用加权一阶局域法单步预测模型进行多步预测时计算量大,且存在误差累积效应的不足,本文提出了基于相空间重构技术的加权一阶局域法多步预测模型,通过实际算例分析显示,本文方法较改进前有较好的适应能力和预测精度。  相似文献   

12.
We introduce a level set method for the computation of multi-valued solutions of a general class of nonlinear first-order equations in arbitrary space dimensions. The idea is to realize the solution as well as its gradient as the common zero level set of several level set functions in the jet space. A very generic level set equation for the underlying PDEs is thus derived. Specific forms of the level set equation for both first-order transport equations and first-order Hamilton-Jacobi equations are presented. Using a local level set approach, the multi-valued solutions can be realized numerically as the projection of single-valued solutions of a linear equation in the augmented phase space. The level set approach we use automatically handles these solutions as they appear  相似文献   

13.
A programming system is a language made from a fixed class of data abstractions and a selection of familiar deterministic control and assignment constructs. It is shown that the sets of all ‘before-after’ first-order assertions which are true of programs in any such language can uniquely determine the input-output semantics of the language providing one allows the use of auxiliary operators on its ground types.After this, we study programming systems wherein the data types are syntactically defined using a first-order specification language with the objective of eliminating these auxiliary operators. Especial attention is paid to algebraic specifications, complete first-order specifications; and to arithmetical computation in the context of a specified programming system.  相似文献   

14.
Multiple time delays and strong interactions among different loops are the main problems in the design of multivariable controller for non-square systems. In this paper, the concept of effective open-loop transfer function (EOTF) is extended to non-square systems. By applying the internal model control (IMC) method, the controllers with equivalent models are designed. For practical applications, the NPSO algorithm is used to obtain the parameters of the incremental PID with first-order lag filter. This new method does not only avoid the complex computation caused by the procedure of decoupling first and then designing controllers but also employs the advantages of IMC-PID's suitable for large time delay systems and strong robustness. Simulation is carried out to demonstrate the effectiveness of the proposed method; also significant performance improvement has been achieved with the proposed method compared with other methods.  相似文献   

15.
In the late sixties, N. Shor and B. Polyak independently proposed optimal first-order methods for solving non-smooth convex optimization problems. In 1982 A. Nemirovski proposed optimal first-order methods for solving smooth convex optimization problems, which utilized auxiliary line search. In 1985 A. Nemirovski and Yu. Nesterov proposed a parametric family of optimal first-order methods for solving convex optimization problems with intermediate smoothness. In 2013 Yu. Nesterov proposed a universal gradient method which combined all good properties of the previous methods, except the possibility of using auxiliary line search. One can typically observe that in practice auxiliary line search improves performance for many tasks. In this paper, we propose the apparently first such method of non-smooth convex optimization allowing the use of the line search procedure. Moreover, it is based on the universal gradient method, which does not require any a priori information about the actual degree of smoothness of the problem. Numerical experiments demonstrate that the proposed method is, in some cases, considerably faster than Nesterov's universal gradient method.  相似文献   

16.
在线闭环系统传感器的故障, 由于控制器的调节作用, 使得其故障诊断变得复杂. 本文针对定值和随动单 闭环系统传感器故障, 在正常系统和故障系统动态特性分析基础上, 提出了一种基于系统动态趋势和数据驱动的故 障诊断方法. 该方法利用动态窗口残差数据实现故障监测; 以数据变化最大值实现故障估计; 采用二次线性回归实 现故障分离; 建立了系统故障监测、故障估计和故障分离的静态模型; 同时给出了诊断模型在线应用的标定方法和 诊断流程. 通过实验验证了方法的有效性和诊断的高精度. 该方法适用于一般的一阶定值和随动闭环控制系统传 感器的实时故障诊断.  相似文献   

17.
Logic of transition systems   总被引:1,自引:1,他引:0  
Labeled transition systems are key structures for modeling computation. In this paper, we show how they lend themselves to ordinary logical analysis (without any special new formalisms), by introducing their standard first-order theory. This perspective enables us to raise several basic model-theoretic questions of definability, axiomatization and preservation for various notions of process equivalence found in the computational literature, and answer them using well-known logical techniques (including the Compactness theorem, Saturation and Ehrenfeucht games). Moreover, we consider what happens to this general theory when one restricts attention to special classes of transition systems (in particular, finite ones), as well as extended logical languages (in particular, infinitary first-order logic). We hope that this puts standard logical formalisms on the map as a serious option for a theory of computational processes. As a side benefit, our approach increases comparability with several other existing formalisms over labeled transition systems (such as Process Algebra or Modal Logic). We provide some pointers to this effect, too.  相似文献   

18.
The transformation between conjunctive and disjunctive canonical forms is useful in domains such as theorem proving, function minimization, and knowledge representation. In this paper, we present a concurrent algorithm for this transformation, suitable for first-order logic theories. The proposed algorithm use the holographic relation between these normal forms in order to avoid the generation of noncondensed and subsumed (dual) clauses. We also stress the facts that, in first-order logic, this transformation is asymmetric and that disjunctive normal form, in some special cases, may be not unique, depending on choices about which subsumptions are allowed or not. The algorithm, which is part of a theorem-proving knowledge representation project, has been implemented and tested.  相似文献   

19.
计量逻辑理论是逻辑概念程度化研究方向的一个重要分支。但目前计量谓词逻辑的相关研究中,都不曾涉及推广规则。一阶逻辑公式的准真度理论是计量谓词逻辑的一个重要的研究成果,讨论经过推广规则后,一阶逻辑公式准真度的变化情况,证明经过推广规则后,一阶逻辑公式在基于准真度的一阶逻辑公式集的分类中类别不变。  相似文献   

20.
We propose an efficient preconditioning technique for the numerical solution of first-order partial differential equations (PDEs). This study has been motivated by the computation of an invariant torus of a system of ordinary differential equations. We find the torus by discretizing a nonlinear first-order PDE with a full two-dimensional Fourier spectral method and by applying Newton’s method. This leads to large nonsymmetric linear algebraic systems. The sparsity pattern of these systems makes the use of direct solvers prohibitively expensive. Commonly used iterative methods, e.g., GMRes, BiCGStab and CGNR (Conjugate Gradient applied to the normal equations), are quite slow to converge. Our preconditioner is derived from the solution of a PDE with constant coefficients; it has a fast implementation based on the Fast Fourier Transform (FFT). It effectively increases the clustering of the spectrum, and speeds up convergence significantly. We demonstrate the performance of the preconditioner in a number of linear PDEs and the nonlinear PDE arising from the Van der Pol oscillator  相似文献   

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