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Robust Finite-time Synchronization of Non-identical Fractional-order Hyperchaotic Systems and Its Application in Secure Communication

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IEEE/CAA Journal of Automatica Sinica 2019年第1期6卷 228-235页

作者： Hadi Delavari Milad Mohadeszadeh the Electrical Engineering Department Hamedan University of Technology

This paper proposes a novel adaptive sliding mode control(SMC) method for synchronization of non-identical fractional-order(FO) chaotic and hyper-chaotic systems. Under the existence of system uncertainties and external disturbances,finite-time synchronization between two FO chaotic and hyperchaotic systems is achieved by introducing a novel adaptive sliding mode controller(ASMC). Here in this paper, a fractional sliding surface is proposed. A stability criterion for FO nonlinear dynamic systems is introduced. Sufficient conditions to guarantee stable synchronization are given in the sense of the Lyapunov stability theorem. To tackle the uncertainties and external disturbances, appropriate adaptation laws are introduced. Particle swarm optimization(PSO) is used for estimating the controller parameters. Finally, finite-time synchronization of the FO chaotic and hyper-chaotic systems is applied to secure communication.

关键词： Adaptive sliding mode control (ASMC) chaos synchronization fractional order (FO) hyper-chaotic system Lyapunov theorem secure communication

order parameters of liquid crystal on the rubbing surfaces of alignment layers

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Science China(Technological Sciences) 2002年第6期45卷 654-660页

作者：宣丽乌日娜彭增辉于涛张力阮圣平 Tatsuo Uchida Department of Electronics Graduate School of Engineering.Tohoku UniversitySendaiJapan

Liquid crystal (LC) alignment is most important in LC devices. In this paper, we quantitatively analyze the LC scalar order parameters on the rubbed surface of an alignment layer. Careful measurement of dichroic infrared absorbance is performed. The result gives the evidence that the order parameter of LC just on the rubbed alignment film is only 1/3-1/2 that in the LC bulk.

关键词： liquid crystal, rubbed surface, alignment layer, order parameters.

Dynamics of a neuron exposed to integer-and fractional-order discontinuous external magnetic flux

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Frontiers of Information Technology & Electronic Engineering 2019年第4期20卷 584-590页

作者： Karthikeyan RAJAGOPAL Fahimeh NAZARIMEHR Anitha KARTHIKEYAN Ahmed ALSAEDI Tasawar HAYAT Viet-Thanh PHAM Center for Nonlinear Dynamics Defence University Institute of Energy Mekelle University Biomedical Engineering Department Amirkabir University of Technology NAAM Research Group Faculty of Science King Abdulaziz University Department of Mathematics Quaid-i-Azam University Modelling Evolutionary Algorithms Simulation and Artificial Intelligence Faculty of Electrical and Electronics Engineering Ton Duc Thang University

We propose a modified Fitzhugh-Nagumo neuron(MFNN) model. Based on this model, an integerorder MFNN system(case A) and a fractional-order MFNN system(case B) were investigated. In the presence of electromagnetic induction and radiation, memductance and induction can show a variety of distributions. Fractionalorder magnetic flux can then be considered. Indeed, a fractional-order setting can be acceptable for non-uniform diffusion. In the case of an MFNN system with integer-order discontinuous magnetic flux, the system has chaotic and non-chaotic attractors. Dynamical analysis of the system shows the birth and death of period doubling, which is a sign of antimonotonicity. Such a behavior has not been studied previously in the dynamics of neurons. In an MFNN system with fractional-order discontinuous magnetic flux, different attractors such as chaotic and periodic attractors can be observed. However, there is no sign of antimonotonicity.

关键词： Fitzhugh-Nagumo Chaos Fractional order Magnetic flux

Wavelet Analysis of the Shaft order Perturbation and Stall Inception in an Axial Compressor

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Journal of Thermal Science 2013年第3期22卷 223-228页

作者： HE Xiang MA Hongwei ZHANG Jun Wei Wei National Key Laboratory of Science and Technology on aero-Engines School of Energy and Power Engineering Bei-hang University

An experiment was carried out in a low-speed large-scale axial-compressor. Dynamic pressure signals were measured and analyzed with a wavelet transform. At all stable operating condition, a shaft order perturbation was observed from the dynamic pressure signals and wavelet power spectrums. By measuring the tip clearance, blade pitches and blade thickness distributions, a rotor asymmetry was identified in this compressor, which is strongly linked to the shaft order perturbation. Modal wave appears at the near-stall operating point. The propagation speed of the modal wave is about 20% rotating speed. At the peak of the modal wave, the intensity of the shaft-order-perturbation increases obviously, while it decays very fast at the trough of modal wave. By throttling the compressor, modal stall occurs in several seconds and only one stall-cell was detected. The stall cell grows smoothly out of the modal wave and its propagation speed is increased to 30% rotor speed. In several revolutions before stall, the intensity of the modal wave is increasing and a shaft order perturbation produced by modal-wave grows into stall inception which indicate stall onset but not trigger stall.

关键词： axial compressor, stall inception, modal wave, wavelet analysis, shaft order perturbation

Optimized high order product quantization for approximate nearest neighbors search

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Frontiers of Computer Science 2020年第2期14卷 259-272页

作者： Linhao LI Qinghua HU School of Artificial Intelligence Hebei University of TechnologyTianjin 300401China Tianjin Key Lab of Machine Learning School of Computer Science and TechnologyTianjin UniversityTianjin 300072China

Product quantization is now considered as an effective approach to solve the approximate nearest neighbor(ANN)search.A collection of derivative algorithms have been ***,the current techniques ignore the intrinsic high order structures of data,which usually contain helpful information for improving the computational *** this paper,aiming at the complex structure of high order data,we design an optimized technique,called optimized high order product quantization(O-HOPQ)for ANN *** O-HOPQ,we incorporate the high order structures of the data into the process of designing a more effective subspace decomposition *** a result,spatial adjacent elements in the high order data space are grouped into the same ***,O-HOPQ generates its spatial structured codebook,by optimizing the quantization *** from the structured codebook,the global optimum quantizers can be obtained effectively and *** results show that appropriate utilization of the potential information that exists in the complex structure of high order data will result in significant improvements to the performance of the product ***,the high order structure based approaches are effective to the scenario where the data have intrinsic complex structures.

关键词： product quantization high order structured data tensor theory approximate nearest neighbor search

Fuzzy Adaptive Control of a Fractional order Chaotic System With Unknown Control Gain Sign Using a Fractional order Nussbaum Gain

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IEEE/CAA Journal of Automatica Sinica 2019年第3期6卷 816-823页

作者： Khatir Khettab Samir Ladaci Yassine Bensafia IEEE the Electrical Engineering Department University of Mohamed Boudiaf M’sila 28000 Algeria Electrical Engineering Department University of Skikda the EEA Department National Polytechnic School of Constantine B. P. 75 A Ali Mendjli 25000 Constantine Algeria SP-Lab Laboratory Department of Electronics Mentouri University Yassine Bensafia is with the Electrical Engineering Department University of Bouira

In this paper we propose an improved fuzzy adaptive control strategy, for a class of nonlinear chaotic fractional order(SISO) systems with unknown control gain sign. The online control algorithm uses fuzzy logic sets for the identification of the fractional order chaotic system, whereas the lack of a priori knowledge on the control directions is solved by introducing a fractional order Nussbaum gain. Based on Lyapunov stability theorem, stability analysis is performed for the proposed control method for an acceptable synchronization error level. In this work, the Gr ¨unwald-Letnikov method is used for numerical approximation of the fractional order systems. A simulation example is given to illustrate the effectiveness of the proposed control scheme.

关键词： Adaptive fuzzy control chaos synchronization fractional order Nussbaum function Lyapunov stability nonlinear fractional order systems

Stable Model order Reduction Method for Fractional-order Systems Based on Unsymmetric Lanczos Algorithm

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IEEE/CAA Journal of Automatica Sinica 2019年第2期6卷 485-492页

作者： Zhe Gao the College of Light Industry Liaoning University

This study explores a stable model order reduction method for fractional-order systems. Using the unsymmetric Lanczos algorithm, the reduced order system with a certain number of matched moments is generated. To obtain a stable reduced order system, the stable model order reduction procedure is discussed. By the revised operation on the tridiagonal matrix produced by the unsymmetric Lanczos algorithm, we propose a reduced order modeling method for a fractional-order system to achieve a satisfactory fitting effect with the original system by the matched moments in the frequency domain. Besides, the bound function of the order reduction error is offered. Two numerical examples are presented to illustrate the effectiveness of the proposed method.

关键词： Fractional-order systems order reduction stable reduced order systems unsymmetric Lanczos algorithm

Sensor Fault Estimation and Fault-Tolerant Control for a Class of Takagi-Sugeno Markovian Jump Systems with Partially Unknown Transition Rates Based on the Reduced-order Observer

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Journal of Systems Science & Complexity 2018年第6期31卷 1405-1422页

作者： LI Xiaohang LU Dunke ZHANG Wei ZHU Fanglai School of Electronic and Electric Engineering Shanghai University of Engineering ScienceShanghai 201620China School of Electrical Engineering and Automation Henan Polytechnic UniversityJiaozuo 454010China School of Electronic and Electric Engineering Shanghai University of Engineering ScienceShanghai 201620China. Engineering Training Center Shanghai University of Engineering ScienceShanghai 201620China. College of Electronics and Information Engineering Tongji UniversityShanghai 200093China.

This paper addresses the problem on sensor fault estimation and fault-tolerant control for a class of Takagi-Sugeno Markovian jump systems,which are subjected to sensor faults and partially unknown transition ***,the original plant is extended to a descriptor system,where the original states and the sensor faults are assembled into the new state ***,a novel reduced- order observer is designed for the extended system to simultaneously estimate the immeasurable states and sensor ***,by using the estimated states obtained from the designed observer,a state- feedback fault-tolerant control strategy is developed to make the resulting closed-loop control system stochastically *** on linear matrix inequality technique,algorithms are presented to compute the observer gains and control *** effectiveness of the proposed observer and controller are validated by a numerical example and a compared study,respectively,and the simulation results reveal that the proposed method can successfully estimate the sensor faults and guarantee the stochastic stability of the resulting closed-loop system.

关键词： Fault-tolerant control Markovian jump system partially unknown transition rates reduced- order observer sensor fault estimation T-S fuzzy system

Robust D-Stability Test of LTI General Fractional order Control Systems

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IEEE/CAA Journal of Automatica Sinica 2020年第3期7卷 853-864页

作者： Reza Mohsenipour Xinzhi Liu Department of Aerospace Engineering Sharif University of TechnologyTehran ***Iran Department of Applied Mathematics University of WaterlooOntario N2L 3G1Canada

This work deals with the robust D-stability test of linear time-invariant(LTI) general fractional order control systems in a closed loop where the system and/or the controller may be of fractional order. The concept of general implies that the characteristic equation of the LTI closed loop control system may be of both commensurate and non-commensurate orders, both the coefficients and the orders of the characteristic equation may be nonlinear functions of uncertain parameters, and the coefficients may be complex numbers. Some new specific areas for the roots of the characteristic equation are found so that they reduce the computational burden of testing the robust D-stability. Based on the value set of the characteristic equation, a necessary and sufficient condition for testing the robust D-stability of these systems is derived. Moreover, in the case that the coefficients are linear functions of the uncertain parameters and the orders do not have any uncertainties, the condition is adjusted for further computational burden reduction. Various numerical examples are given to illustrate the merits of the achieved theorems.

关键词： Fractional order control system LTI system robust D-stability value set