RC—Nullor网络的一种拓扑分析方法及不定导纳矩阵的形成

本文提出了一种ＲＣ－ｎｕｌｌｏｒ网络拓扑分析的简便方法，并着重研究这种方法中不定导纳矩阵的直接形成。     

A flux-controlled model of meminductor and its application in chaotic oscillator

A meminductor is a new type of memory device developed from the memristor.We present a mathematical model of a flux-controlled meminductor and its equivalent circuit model for exploring the properties of the meminductor in a nonlinear circuit.We explore the response characteristics of the meminductor under the exciting signals of sinusoidal,square,and triangular waves by using theoretical analysis and experimental tests,and design a meminductor-based oscillator based on the model.Theoretical analysis and experiments show that the meminductor-based oscillator possesses complex bifurcation behaviors and can generate periodic and chaotic oscillations.A special phenomenon called the co-existent oscillation that can generate multiple oscillations(such as chaotic,periodic oscillations as well as stable equilibrium) with the same parameters and different initial conditions occurs.We also design an analog circuit to realize the meminductor-based oscillator,and the circuit experiment results are in accordance with the theory analysis.     

蔡氏结型忆阻器的简化及其神经元电路的硬件实现

蔡氏结型忆阻器(Chua corsage memristor, CCM)属于压控型局部有源忆阻器,具有复杂的动力学行为,在神经形态计算领域具有潜在的应用价值.根据静态电压-电流特性曲线, CCM可分为二翼、四翼和六翼型.本文基于神经形态行为的产生机制,将CCM的数学模型进行简化,简化后的模型表达式中无绝对值符号,且小信号等效电路的导纳函数与简化前完全相同.进一步采用简化的CCM模型与电容和电感元件相连,构建了三阶神经元电路.利用局部有源、混沌边缘、及李雅普诺夫指数等理论分析方法,预测了该神经元电路产生神经形态行为的参数域.根据简化的CCM数学模型,采用运算放大器、乘法器、电阻和电容等常用电路元件构建了该忆阻器的电路仿真器,并连接电容和电感进一步给出了神经元电路的硬件实现.实验结果表明该神经元电路可以产生丰富的神经形态行为,包括静息状态、周期尖峰、混沌状态、双峰响应、周期振荡现象、全或无现象和尖峰簇发现象.     

基于混沌集的图像加密算法

该文提出一种基于包含离散混沌系统、连续混沌系统的混沌系统集的混沌加密算法,该加密算法可以根据加密强度需求选择不同的混沌系统组合,利用图像像素的像素均值及像素坐标值为参数控制混沌密钥产生,增强混沌密钥与明文数据之间的联系。在加密基础上,将密文按位切割成3个数据后伪装隐藏在一个处理后的公开图像内,改变了密文外观特性。通过对加密后的图像进行图像直方图分析、相邻像素相关性分析及图像信息熵分析,表明该加密算法有效,在图像保密传输中具有应用潜力。

     

超混沌序列对DS-UWB多址性能的改善

利用Roessler超混沌系统构造了一种新的超混沌序列,分析了序列的相关特性,并将其应用于直接序列超宽带（DS—UWB）系统中,以提高它的误码性能。建立了DS-UWB通信系统的模型,以超混沌序列作地址码对高斯白噪声信道中多用户DS—UWB系统误码率进行了分析,并将其与m序列作地址码时的相应性能进行了比较。由分析和仿真可知,构造的新的超混沌序列能较好地改善DS-UWB的多址性能。     

Analysis and implementation of a new hyperchaotic system

Based on a modified Lorenz system, a relatively simple four-dimensional continuous autonomous hyperchaotic system is proposed by introducing a state feedback controller. The system consists of four coupled first-order ordinary differential equations with three nonlinear cross-product terms. Some dynamical properties of this hyperchaotic system, including equlibria, stability, Lyapunov exponent spectrum and bifurcation, are analysed in detail. Moreover, an electronic circuit diagram is designed for demonstrating the existence of the hyperchaos, and verifying computer simulation results.     

Modeling random telegraph signal noise in CMOS image sensor under low light based on binomial distribution

The random telegraph signal noise in the pixel source follower MOSFET is the principle component of the noise in the CMOS image sensor under low light. In this paper, the physical and statistical model of the random telegraph signal noise in the pixel source follower based on the binomial distribution is set up. The number of electrons captured or released by the oxide traps in the unit time is described as the random variables which obey the binomial distribution. As a result,the output states and the corresponding probabilities of the first and the second samples of the correlated double sampling circuit are acquired. The standard deviation of the output states after the correlated double sampling circuit can be obtained accordingly. In the simulation section, one hundred thousand samples of the source follower MOSFET have been simulated,and the simulation results show that the proposed model has the similar statistical characteristics with the existing models under the effect of the channel length and the density of the oxide trap. Moreover, the noise histogram of the proposed model has been evaluated at different environmental temperatures.     

A new Rosslor hyperchaotic system and its realization with systematic circuit parameter design

Based on two modified Rosslor hyperchaotic systems, which are derived from the chaotic Rosslor system by introducing a state feedback controller, this paper proposes a new switched Rosslor hyperchaotic system. The switched system contains two different hyperchaotic systems and can change its behaviour continuously from one to another via a switching function. On the other hand, it presents a systematic method for designing the circuit of realizing the proposed hyperchaotic system. In this design, circuit state equations are written in normalized dimensionless form by rescaling the time variable. Furthermore, an analogous circuit is designed by using the proposed method and built for verifying the new hyperchaos and the design method. Experimental results show a good agreement between numerical simulations and experimental results.     

N型局部有源忆阻器的神经形态行为

局部有源忆阻器(locally-active memristor,LAM)凭借其高集成度、低功耗和局部有源特性等优点,在神经形态计算领域显示出巨大的潜力.本文提出了一种简单的N型LAM数学模型,通过揭示其非线性动力特性,设计了N型LAM神经元电路.采用Hopf分岔、数值分析等方法定量研究了该电路的动力学行为,成功模拟了多种神经形态行为,包括全或无行为、尖峰、簇发、周期振荡等.并利用该神经元电路结构模拟了生物触觉神经元的频率特性.仿真结果表明:当输入信号幅值低于阈值时,神经元电路输出信号的振荡频率与输入信号强度呈正相关(即兴奋状态),并在阈值处达到最大值.随后,继续增大激励强度,振荡频率则逐渐降低(即保护性抑制状态).最后,设计了N型LAM硬件仿真器,并完成了人工神经元电路的硬件实现,实验结果与仿真结果、理论分析相一致,验证了该N型LAM具备的神经形态行为.     

一个新的混沌系统及其电路设计与实现

提出了一个连续三维二次自治混沌系统.该系统与Lorenz、Rossler、Chen、Lu系统不同,它只含一个系统参数,但具有五个平衡点.通过理论分析、Lyapunov指数谱、分岔图以及电路设计与实验,验证了系统的混沌行为.