Chaowen Feng

Reliability and Performance Evaluation of QCA Devices With Rotation Cell Defect

As a novel nanotechnology, quantum-dot cellular automata (QCA) can achieve dense packages due to the extremely small size of quantum dots. However, fabrication defects and fault rates in the nanotechnology are expected to be quite high. In this paper, the behaviors of basic QCA devices in the presence of cell rotation are thoroughly analyzed in order to study their rotation defect tolerances and determine the ranges of allowable rotation angles. Rotation effect of QCA cell is modeled by using modified coherence vector formalism and rotation angle. The performances of five basic QCA devices with rotation cell defect are simulated under various cell sizes. The results show that different QCA devices have different rotation angle tolerances. The inverter is the weakest structure while the straight wire is the most reliable structure if measured by the smallest angle that impacts success rate, and the bigger cell size has a negative effect on allowable rotation angle range. More analysis results show that the diagonal cell and the cell close to the output perform the worst rotation tolerance on the inverter and the interconnect, respectively. Furthermore, the power gain of rotation defect device is discussed and the finding is provided that moderate rotation error can be restored at the location that is three cells away from the defect.

Design and Simulation of Turbo Encoder in Quantum-Dot Cellular Automata

Quantum-dot cellular automata (QCA) is a potential nanoelectronic technology for information processing. To be considered as a suitable CMOS candidate, QCA must be able to implement complex real-time applications of bit-serial information processing, which lacks of enough investigation. Turbo encoding is one of such applications, which refers to three representative issues of bit-serial circuits: convolution computation, feedback, and serial data permutation. The inherent shift-register nature of QCA offers an advantage to performing convolution computation but poses handicaps to resolve the latter two issues. How to manage the ambivalent effects of shift-register nature is investigated in this paper, which determines the efficient design of Turbo encoder. A strobe scheme based on main-branch wire crossing is proposed to efficiently make data choosing that is the communally key procedure of the implementation of feedback and serial data permutation. On this basis, a method of implementing recursive convolutional encoder with multifeedback is proposed. A two-stage pipelining interleaver is presented. Finally, a Turbo encoder is implemented using QCA based on these approaches and simulation demonstrates that it performs well.

A study on hyperchaotic system implemented by SETMOS

In this paper, we proposed a hardware implementation method for generating a sandwich hyperchaotic attractor. Based on the negative differential conductance (NDR) characteristic of hybrid single-electron transistor and complimentary metal-oxide-semiconductor (SETMOS) architecture, Saito hysteresis chaos generator (SHCG) was constructed using a cellular neural network (CNN). Complex dynamical behaviors of the hyperchaotic system were investigated by means of bifurcation diagram, Lyapunov exponent spectrum, Poincare mapping and power spectrum. Numerical simulations verify the theoretical analysis and design method and show that the implemented hyperchaotic circuit works very well.

Control of magnetic vortex polarity by the phase difference between voltage signals

Using micromagnetic simulations, we investigate the voltage control of magnetic vortex polarity based on a designed multiferroic heterostructure that contains two separate piezoelectric films beneath a magnetostrictive nanodisk. The results show that controllable switching of vortex polarity can be achieved by proper modulation of the phase difference between two sinusoidal voltage pulses V1 and V2, which are applied to the two separate piezoelectric films, respectively. The frequencies of V1 and V2 are set at the gyrotropic eigenfrequency fG of the nanodisk, and the vortex polarity switching is completed via the nucleation-annihilation process of the vortex-antivortex pair. Our findings provide an additional effective means for ultralow power switching of the magnetic vortex, which lays the foundation for voltage-controlled vortex random access memory.

Analysis and Synchronization of a Novel Memristor Hyper-Chaotic System

In this work, a new hyper-chaotic system based on memristor is proposed and the anti-synchronization is demonstrated. Through the analysis of the system behaviors, including the stability of equilibrium set, Lyapunov exponents and phase portraits, it demonstrates the proposed system is a new hyper-chaotic system with the features of infinite equilibrium points and complex dynamic characteristics. Besides the anti-synchronization of the memristor hyper-chaotic system is realized. It is proven that the dynamics of the anti-synchronization error is globally and asymptotically stable based on the Lyapunov stability theory. Numerical simulations are given in the end. It provides the theoretical foundation for the aspects of security communication and image encryption.

Tracking control and synchronization of memristor hyper-chaotic system

In this work, a new hyper-chaotic system based on memristor is proposed and the tracking control and synchronization is achieved. The dynamic characteristics of memristor hyper-chaotic system are analyzed theoretically. Then, the synchronization controllers are designed to realize the chaotic synchronization with the different structure and the tracking synchronization with the given signal. Besides, the effectiveness of synchronization controllers are verified by the Lyapunov principle. The simulated results demonstrated that the memristor hyper-chaotic system has good performance in the tracking control and synchronization. It provides new theoretical guidance for the application of the nano-electronic chaotic system in secure communication and image encryption.

Three-dimensional quantum cellular neural network and its application to image processing

A three-dimensional quantum cellular neural network is proposed by using the quantum cellular automata as neuron cells. The three-dimensional quantum cellular neural network consists of two layers of quantum cellular automata array and possesses the A cloning template, B cloning template, and threshold. The image processing functions such as hole filling and corner detecting were performed by using the polarization of quantum cellular automata as pixel value and selecting different cloning templates and thresholds. The SIMULINK model is employed to simulate image processing functions and the simulation results demonstrate the effectiveness of the proposed quantum cellular neural networks.