Experimental study on tracking the state of analog Chua's circuit with particle filter for chaos synchronization

临床资料男,43岁,因双下肢无力7年,加重并累及上肢2个月于2004年3月10日来我院就诊.患者于1997年7月发现双下肢无力,自认为肥胖所致,2年后症状加重,双腿僵硬,偶有面部及嘴唇抖动,呛咳.曾就诊过多家医院,2002年8月在北京肌肉病会诊中心诊为"肢带综合征,运动神经元病可疑",先后应用过神经生长素、肌萎灵及中草药等治疗无效.于2004年1月出现双手无力、行走困难,不能独立完成上楼、下蹲起立等动作.既往体健.婚后育一女,体健.查体:血压 140/80 mm Hg(1 mm Hg=0.133 kPa),身高176 cm,体重106 kg,乳房肥大,心、肺、腹检查正常.睾丸萎缩.神经系统检查:意识清楚,讷吃,伸舌困难,舌体肥厚、震颤,边缘有齿痕。

Kennedy病一例报告

In this study, a new controller for chaos synchronization is proposed. It consists of a state feedback controller and a robust control term using Legendre polynomials to compensate for uncertainties. The truncation error is also considered. Due to the orthogonal functions theorem, Legendre polynomials can approximate nonlinear functions with arbitrarily small approximation errors. As a result, they can replace fuzzy systems and neural networks to estimate and compensate for uncertainties in control systems. Legendre polynomials have fewer tuning parameters than fuzzy systems and neural networks. Thus, their tuning process is simpler. Similar to the parameters of fuzzy systems, Legendre coefficients are estimated online using the adaptation rule obtained from the stability analysis. It is assumed that the master and slave systems are the Lorenz and Chen chaotic systems, respectively. In secure communication systems, observer-based synchronization is required since only one state variable of the master system is sent through the channel. The use of observer-based synchronization to obtain other state variables is discussed. Simulation results reveal the effectiveness of the proposed approach. A comparison with a fuzzy sliding mode controller shows that the proposed controller provides a superior transient response. The problem of secure communications is explained and the controller performance in secure communications is examined.

Synchronization of two different chaotic systems using Legendre polynomials with applications in secure communications

In this paper, synchronization of chaotic Colpitts circuits using a particle filter (PF) to combat the additive white Gaussian noise (AWGN) channel effect is studied by numeric simulations. A novel PF algorithm suitable for chaos synchronization is proposed. With this algorithm, chaos synchronization of Colpitts circuits can be achieved and maintained in AWGN channels. Parameters in the proposed PF algorithm are studied to understand their effects on synchronization performance. The synchronization performance using the proposed PF algorithm is compared with those using other digital filters, such as the extended Kalman filter and the generic PF. It is found that the proposed PF algorithm performs better than the other digital filters. Simulation results also show that the particle number is not very critical to the synchronization performance when this PF algorithm is used.

Particle Filter-Based Synchronization of Chaotic Colpitts Circuits Combating AWGN Channel Distortion

For chaotic trajectories, when the system parameters are fixed, they are generally confined in a bounded state space. In this paper, we propose an adaptive regularized particle filter (RPF), which makes the best of this inherent characteristic, for identical synchronization of chaotic Colpitts circuits combating additive white Gaussian noise (AWGN) channel distortion. This proposed filter incorporates RPF that resamples from a continuous approximation of the posterior density to avoid sample impoverishment and then utilizes the revised Kullback–Leibler distance (KLD) sampling to adaptively select the number of particles used. Compared with the existing particle filters (PFs) with fixed large number of particles, this proposed adaptive RPF propagates less number of particles with similar performance and thus provides a much more efficient solution for this problem.

Adaptive Regularized Particle Filter for Synchronization of Chaotic Colpitts Circuits in an AWGN Channel

In this work, synchronization of chaotic Colpitts circuits, using adaptive controllers to combat circuit parameter mismatches and channel distortions, is studied by numerical simulations. Synchronization errors caused by different main circuit components are compared, and compensation for time-constant and time-varying circuit parameter mismatches is demonstrated. Different kinds of channel distortions, including time-constant and time-varying channel attenuation, Additive White Gaussian Noise (AWGN) are all investigated by numerical simulations and discussed. Simulation results indicated that the synchronization performance of chaotic Colpitts circuits can be greatly improved by applying adaptive controllers when parameter mismatches and channel attenuation are considered as time-constant or time-varying, but have no obvious enhancements regarding the effect on AWGN channel.

Adaptive synchronization of chaotic Colpitts circuits against parameter mismatches and channel distortions

In this letter, we investigate error performance of rectangular pulse-shaped orthogonal time frequency space (OTFS) modulation with a practical receiver. Specifically, we consider an essential bandpass filter at receiver RF front-end, which has been ignored in existing works. We analyse the effect of rectangular pulses on practical OTFS receiver performance, and derive the exact forms of interference in delay-Doppler (DD) domain. We demonstrate that the transmitted information symbols in certain regions of the DD domain are severely contaminated. As a result, there is an error floor in the receiver error performance, which needs to be addressed for such OTFS waveform in practical systems.

Error Performance of Rectangular Pulse-Shaped OTFS With Practical Receivers

The paper presents an approach to achieving synchronization between chaotic Colpitts circuits in practical communications. By applying an adaptive controller to compensate for the parameter mismatches between transmitter and receiver and to offset the channel distortions, the synchronization performance is markedly improved. Both time-constant and time-varying circuit parameter mismatches and channel distortions are considered in simulations.

Cheng Shen

Papers

Adaptive synchronization of chaotic Colpitts circuits against parameter mismatches and channel distortions

Error Performance of Rectangular Pulse-Shaped OTFS With Practical Receivers

Synchronizing chaotic Colpitts circuits adaptively with parameter mismatches and channel distortions