Generators by the quadratic exponential method

Based on the quadratic exponential method, this paper constructs two types of generators over finite field Fq, the digital quadratic exponential generator and quadratic exponential pseudorandom vector generator. We investigate the distribution of the sequence generated by the generators, and present results about their one dimensional discrepancy. The proofs are based on the estimate of certain character sum over Fq. Ift is the least period of the sequence and t≥q^1/2＋2c, then the bound of the discrepancy is O（t^-1/4q^1/8＋τ logq） for any ε 〉 0. It shows that the sequence is asymptotically uniformly distributed.     

时滞双向联想记忆神经网络的全局指数稳定新条件

运用不等式αПk=1^m blk≤1/r ∑k=1^m qkbk^r＋1/rα^r（α≥0,bk≥0,qk〉0,∑k=1^m qk=r-1,r〉1）和构造新的李雅普洛夫泛函方法,研究了时滞双向联想记忆神经网络的全局指数稳定性。去掉了相关文献中有关传递函数有界性的假设,给出了较弱的并且不依赖于时滞的判别条件,增强了模型的适用性,在网络的分析和设计中发挥着重要作用。最后我们通过模拟仿真进一步说明所得结果的正确性,并对双向联想记忆神经网络的收敛速度作了分析。     

一种多自由度阻尼体系动力问题的高阶分析方法

传统动力时程直接积分法多采用低阶数值格式,需要选择非常小的时间步距才能获得满足精度要求的动力分析结果.该文将结构动力时程分析的积分求微法推广至多自由度情形,发展了一种具有较高计算效率的多自由度阻尼体系的动力时程高阶分析方法.将相邻的ρ个时步组成一个待求解时段,基于多自由度体系动力响应积分解,以精细积分法结合秦九韶算法计...     

建筑结构动力时程响应分析与计算的新方法

基于状态空间理论分析与计算结构动力时程响应问题,根据结构动力学方程,引入结构系统的状态变量,建立结构动力时程响应分析的状态方程,并给出非齐次状态方程的解。对于求解矩阵指数函数有多种解法,着重介绍了凯莱哈密尔顿法、状态空间迭代法和精细积分法。对结构动力时程响应问题按三种解法分别建立了计算格式,并编制了相应计算程序。给出若干数值算例,其计算结果表明,状态空间法分析计算结构动力时程响应精度好、效率高,是一种非常有效的方法。     

基于模糊幂次趋近律的漂浮基空间机器人快速滑模控制

针对空间机械臂轨迹跟踪控制过程中的抖振抑制问题,讨论了一种基于模糊幂次趋近律的快速滑模变结构控制方法。首先运用拉格朗日第二类方程,建立了空间机械臂系统的动力学模型。然后对机械臂的传统滑模面进行改进,设计了一种快速非线性滑模面。利用模糊控制理论,设计了一种模糊幂次趋近律,使机械臂抖振抑制的效果明显,同时也保证了系统的轨迹跟踪控制效果。通过Lyapunov稳定性分析定理,验证了系统的稳定性和收敛性。最后用仿真实验结果证明了所设计控制方法的有效性和可行性。     

基于瓦斯解吸特性推算煤层瓦斯压力的方法

为了能够准确快速确定煤层瓦斯压力,基于煤层瓦斯解吸特性提出了确定煤层瓦斯压力的新方法.通过对煤屑瓦斯扩散过程理论解的进一步分析得出煤层瓦斯压力与煤屑解吸对1~3mm粒径煤样具有确定关系.解吸测定,通过不同公式对解吸数据的拟合分析发现对数公式能够更好的拟合解吸曲线,从而确定对数公式为最佳拟合公式.对数公式中系数A能够表明煤样在不同瓦斯压力下解吸趋势的差异性,与瓦斯压力具有指数关系.并且在不同暴露时间下其数值可以保持在稳定值,可以利用系数A与瓦斯压力的关系进行煤层瓦斯压力的推算.     

宏观事故总量发展趋势的规律探索及模型研究

为研究现代技术管理条件下宏观事故总量发展趋势的规律,选取企业、行业及国家层面的典型宏观事故统计量随时间的变化关系为研究对象,以数学建模的分析模式对比其中规律,并借助马尔萨斯人口学指数规律模型对机理进行描述和解释.结论表明:在一定时间区域内,国家、行业及企业各层面宏观事故总量y的发展随时间x呈指数递减趋势,其回归函数通式可用y=ae^rx表示,且各回归曲线的判定系数R²值证实指数规律相关关系显著.宏观事故总量的发展趋势可能呈现出分段现象,各段存在明显边界的同时,各自仍保持稳定的指数递减规律变化.利用这一规律,通过确定某一宏观事故总量发展趋势的回归函数的方法,可对未来一段时间内的该宏观事故总量值进行预测.     

树脂膜扩散过程实验方法的研究

本文依据指数方程与其曲线图形的形式与液膜控制理论，利用不同方法测定的实验数据描绘出的两条直线，同样可以证实阳离子交换树脂的交换过程是膜扩散。但直线a比直线b要简单，快速测定直线a的方法是扩散的判定方法之一。     

Guaranteed cost distributed fuzzy observer‐based control for a class of nonlinear spatially distributed processes

The guaranteed cost distributed fuzzy (GCDF) observer‐based control design is proposed for a class of nonlinear spatially distributed processes described by first‐order hyperbolic partial differential equations (PDEs). Initially, a T–S fuzzy hyperbolic PDE model is proposed to accurately represent the nonlinear PDE system. Then, based on the fuzzy PDE model, the GCDF observer‐based control design is developed in terms of a set of space‐dependent linear matrix inequalities. In the proposed control scheme, a distributed fuzzy observer is used to estimate the state of the PDE system. The designed fuzzy controller can not only ensure the exponential stability of the closed‐loop PDE system but also provide an upper bound of quadratic cost function. Moreover, a suboptimal fuzzy control design is addressed in the sense of minimizing an upper bound of the cost function. The finite difference method in space and the existing linear matrix inequality optimization techniques are used to approximately solve the suboptimal control design problem. Finally, the proposed design method is applied to the control of a nonisothermal plug‐flow reactor. © 2013 American Institute of Chemical Engineers AIChE J, 59: 2366–2378, 2013     

A Modification of schwarz's sequential likelihood ratio tests in multivariate sequential analysis

By developing and applying certain results on boundary crossing probabilities of generalized likelihood ratio statistics in multiparameter exponential families, we show that Lai's (1988a) modification of Schwarz's (1962) sequential likelihood ratio tests of one-sided hypotheses in the one-parameter case can be extended to general hypotheses in the multiparameter case. Such tests are shown to be asymptotically optimal, from both frequentist and Bayesian points of view, and numerical results are also given to demonstrate their performance.