适用于Android智能手机的灰度均值水印算法

提出了一种适用于Android智能手机的灰度均值数字水印算法。在嵌入阶段,将经过像素重新组织的水印图像嵌入载体图像中;在提取阶段,先提取出初始水印,再判断初始水印是否需要区域替换,如果需要,则进行区域替换,否则不进行;最后,将初始水印还原成所需的水印图像。实验表明,该算法在具有良好水印透明性的同时,对JPEG压缩、加噪声、裁剪等常见的攻击具有鲁棒性。     

精馏塔时滞过程的分数阶PIλDμ控制器设计

本文针对精馏塔不稳定时滞过程,提出一种基于设定值加权的分数阶PIλDμ控制器设计方法.首先采用比例环节构成内环反馈镇定不稳定时滞过程,然后基于等效的过程模型,依据设定值加权方法设计分数阶PIλDμ控制器,并进行了控制器参数整定.仿真结果表明:分数阶PIλDμ控制器可以使精馏塔不稳定时滞过程系统获得良好的动态响应特性,干扰抑制特性以及克服系统参数变化的鲁棒性.     

基于量子力学和拉普拉斯金字塔的图像融合方法

针对数字图像的融合问题,研究一种基于量子力学理论的图像分解方法,并将其结合拉普拉斯金字塔变换,提出一种新的图像融合方法.先把2幅灰度图像表示成量子比特的形式,然后把每幅图像分解成4幅特征子图,根据分解后特征子图的不同含义,使用不同的融合策略分别对子图进行融合.其中一幅子图使用拉普拉斯金字塔变换进行融合,另外3幅子图使用区域梯度取大法进行融合,最后通过重构得到融合图像.仿真实验表明该方法融合效果较好,在主观视觉感受和客观评价指标上均优于传统的图像融合方法.     

Improving the Control Energy in Model Reference Adaptive Controllers Using Fractional Adaptive Laws

This paper presents the analysis of the control energy consumed in model reference adaptive control (MRAC) schemes using fractional adaptive laws, through simulation studies. The analysis is focused on the energy spent in the control signal represented by means of the integral of the squared control input (ISI). Also, the behavior of the integral of the squared control error (ISE) is included in the analysis. The orders of the adaptive laws were selected by particle swarm optimization (PSO), using an objective function including the ISI and the ISE, with different weighting factors. The results show that, when ISI index is taken into account in the optimization process to determine the orders of adaptive laws, the resulting values are fractional, indicating that control energy of the scheme might be better managed if fractional adaptive laws are used.      

Fractional Order Modeling of Human Operator Behavior with Second Order Controlled Plant and Experiment Research

Modeling human operator's dynamics plays a very important role in the manual closed-loop control system, and it is an active research area for several decades. Based on the characteristics of human brain and behavior, a new kind of fractional order mathematical model for human operator in single-input single-output (SISO) systems is proposed. Compared with the traditional models based on the commonly used quasilinear transfer function method or the optimal control theory method, the proposed fractional order model has simpler structure with only few parameters, and each parameter has explicit physical meanings. The actual data and experiment results with the second-order controlled plant illustrate the effectiveness of the proposed method.      

Controllability of Fractional Order Stochastic Differential Inclusions with Fractional Brownian Motion in Finite Dimensional Space

In this paper, sufficient conditions are formulated for controllability of fractional order stochastic differential inclusions with fractional Brownian motion (fBm) via fixed point theorems, namely the Bohnenblust-Karlin fixed point theorem for the convex case and the Covitz-Nadler fixed point theorem for the nonconvex case. The controllability Grammian matrix is defined by using Mittag-Leffler matrix function. Finally, a numerical example is presented to illustrate the efficiency of the obtained theoretical results.      

基于FIC法的不可压缩N-S方程稳定分步算法

近年来发展了一种稳定型分步算法,它是在有限增量微积分(Finite Increment Calculus,FIC)求解不可压缩N-S方程理论框架的基础上,引入了对流和压力梯度投影两个附加变量。该方法有效改善了经典分步算法的压力稳定性,同时避免了标准FIC理论框架中存在的空间高阶导数的计算。该文通过采用此方法对各种雷诺数条件下的顶盖驱动方腔流、圆柱绕流和后台阶流进行数值模拟,并将计算结果与前人计算结果及实验结果进行比较,结果表明本文算法计算结果合理可靠。由此可见该算法具有较强的求解不可压缩流动问题的能力以及良好的应用前景。     

A New Method for Getting Rational Approximation for Fractional Order Differintegrals

In this paper a new algorithm is presented to calculate the poles and zeros to approximate a fractional order (FO) differintegral (s^±α,α∈(0,1)) by a rational function on a finite frequency band ω∈(ω_l,ω_h). The constant phase property of the FO differintegral is the basis for development of the algorithm. Interlacing of real poles and zeros is used to achieve the constant phase. The calculations are done using the asymptotic Bode phase plot. A brief investigation is made to get a good approximation for the Bode phase plot. Two design parameters are introduced to keep the average phase close to the desired phase angle and to keep the error within the allowed bounds. A study is done to empirically understand the relationship between the error and the design parameters. The results thus obtained help in the further calculations. The algorithm is computationally simple and inexpensive, and gives a fairly good approximation of fractance frequency response on the specified frequency band.     

Haar小波求解线性分数阶微积分方程

分数阶微积分方程的应用逐渐受到广大研究者的重视.论文以Haar小波基函数来逼近线性分数阶微积分方程,通过数值算例的数值解与精确解进行比较,结果表明论文方法是有效的且具有较高的精度.     

基于径向基神经网络的分数阶混沌系统控制

针对分数阶混沌系统的控制问题,提出了一种基于径向基函数（RBF）神经网络的控制方法．利用RBF 神经网络对混沌系统的非线性进行补偿,并且神经网络的权值可以通过调整律在线调整．在有参数干扰和外部扰动 的情况下,所设计的控制器仍能使得控制误差渐近收敛到零．以分数阶Liu 混沌系统为例施加控制,仿真结果验证 了该方法的有效性和鲁棒性．