Heterogeneous Memristive Models Design and Its Application in Information Security

Based on the three-dimensional classic Chua circuit, a nonlinear circuit containing two flux-control memristors is designed. Due to the difference in the design of the characteristic equation of the two magnetron memristors, their position form a symmetrical structure with respect to the capacitor. The existence of chaotic properties is proved by analyzing the stability of the system, including Lyapunov exponent, equilibrium point, eigenvalue, Poincare map, power spectrum, bifurcation diagram et al. Theoretical analysis and numerical calculation show that this heterogeneous memristive model is a hyperchaotic five-dimensional nonlinear dynamical system and has a strong chaotic behavior. Then, the memristive system is applied to digital image and speech signal processing. The analysis of the key space, sensitivity of key parameters, and statistical character of encrypted scheme imply that this model can applied widely in multimedia information security.     

Modelling of nanostructured TiO2-based memristors

The fourth fundamental circuit element memristor completes the missing link between charge and magnetic flux. It consists of the function of the resistor as well as memory in nonlinear fashion. The property of the memristor depends on the magnitude and direction of applied potential. This unique property makes it the primitive building block for many applications such as resistive memories, soft computing, neuromorphic systems and chaotic circuits etc. In this paper we report TiO2-based nanostructured memristor modelling. The present memristor model is constructed in MATLAB environment with consideration of the linear drift model of memristor. The result obtained from the linear drift model is well matched with earlier reported results by other research groups.     

忆阻器在神经突触仿生中的应用研究进展

随着对计算机性能要求的不断提高,人们一直在寻找能像人脑一样具有学习记忆功能的新型计算机。自从2008年惠普实验室发现忆阻器以后,发展具有人脑水平的智能计算机成为可能。众所周知,突触是大脑神经网络的基本单元,突触可塑性是学习和记忆的生物学基础。因此,为了实现具有学习和记忆功能的智能计算机,利用忆阻器模拟突触可塑性至关重要。综述了忆阻器在模拟突触的增强、抑制、短时程可塑性和长时程可塑性方面的研究现状,并对其研究前景进行了展望。     

Biorealistic Implementation of Synaptic Functions with Oxide Memristors through Internal Ionic Dynamics

Memristors have attracted broad interest as a promising candidate for future memory and computing applications. Particularly, it is believed that memristors can effectively implement synaptic functions and enable efficient neuromorphic systems. Most previous studies, however, focus on implementing specific synaptic learning rules by carefully engineering external programming parameters instead of focusing on emulating the internal cause that leads to the apparent learning rules. Here, it is shown that by taking advantage of the different time scales of internal oxygen vacancy (V_O) dynamics in an oxide‐based memristor, diverse synaptic functions at different time scales can be implemented naturally. Mathematically, the device can be effectively modeled as a second‐order memristor with a simple set of equations including multiple state variables. Not only is this approach more biorealistic and easier to implement, by focusing on the fundamental driving mechanisms it allows the development of complete theoretical and experimental frameworks for biologically inspired computing systems.     

Synchronisation control for a class of complex-valued fractional-order memristor-based delayed neural networks

In this paper, the problem of drive-response synchronisation of complex-valued fractional-order memristor-based delayed neural networks is discussed via linear feedback control method. By separating complex-valued system into two equivalent real-valued systems, and using the comparison theorem, algebraic criteria are given to ascertain the synchronisation of the considered system with single delay. Meanwhile, for the case of model with multiple delays, the corresponding sufficient conditions are also presented. Because complex-valued system can reduce to real-valued ones when the imaginary part is ignored, the proposed results of this paper generalise existing works on relevant real-valued system. Finally, the effectiveness of the obtained theoretical results is testified by two numerical examples.     

基于忆阻器卷积神经网络的表情识别

忆阻器具有纳米级尺寸、低功耗、类似神经突触等优点,在神经计算、图像分类等领域具有广阔的应用前景。本文提出了一种基于忆阻器卷积神经网络的面部表情识别方法,首先基于忆阻器构建了ResNet卷积神经网络,并对ResNet网络进行剪枝操作,然后将ResNet模型的所有卷积层以及全连接层的权重映射为忆阻器十字交叉阵列中忆阻器的忆导值。实验结果显示忆阻器卷积神经网络模型在FER2013数据集上的识别准确率为63.82%,在CK+数据集上的识别准确率为93.95%。相比与原卷积网路,准确率损失仅分别为0.31%和0.76%。最后测试了忆阻器的非理想特性对准确率的影响,为忆阻器神经网络的实际部署提供参考。     

Semistate models of electrical circuits including memristors

In this paper we present several semistate or differential‐algebraic models arising in nodal analysis of nonlinear circuits including memristors. The goal is to characterize the tractability index of these models under strict passivity assumptions, a key issue for the numerical simulation of circuit dynamics. We show that the main model, which combines memristors' fluxes and charges, is index two. From a technical point of view, this result is based on the use of a projector along the image of the leading matrix, in contrast to previous index analyses. For charge‐controlled memristors, the elimination of fluxes yields an index one system in topologically nondegenerate circuits, and an index two model otherwise. Analogous results are also proved to hold for flux‐controlled memristors. Our framework accommodates coupling effects among resistors, memristors, capacitors and inductors. Copyright © 2010 John Wiley & Sons, Ltd.     

New grounded and floating memristor emulators using OTA and CDBA

In this paper, grounded and floating decremental/incremental memristor emulators have been proposed by using an operational transconductance amplifier (OTA), current differencing buffered amplifier (CDBA), and a grounded capacitor. The proposed memristor emulators are simpler in design over most of the realizations of memristor emulators available in the literature. The proposed configurations of grounded and floating decremental memristor emulators can be easily converted into grounded and floating incremental memristor emulators. The pinched hysteresis loops obtained from proposed memristor emulators are maintained up to 1-MHz frequency in both decremental and incremental configurations. Simulation results have been obtained using a Mentor Graphics Eldo simulation tool in 0.18-μm complementary metal-oxide semiconductor (CMOS) technology parameters. Analog filters have also been designed to verify the performance of proposed grounded and floating memristor emulators.     

Load characterization and power conditioner synthesis using higher-order elements

It is shown that virtually all nonlinear and/or time-varying loads that generate harmonic current distortion can be characterized in terms of so-called higher-order circuit elements. The most relevant higher-order elements exploited in this paper are the memristor, meminductor, and memcapacitor. Such elements naturally arise by introducing constitutive relationships in terms of higher-order voltage and current differentials and integrals. Consequently, the power conditioner necessary to compensate for the load current distortions is synthesized similarly. The new characterization and compensation synthesis is applied to the half-wave rectifier and the controlled bridge converter.