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Journal of Central South University 2016年第3期23卷 636-643页

作者：赵石铁高宪文 school of information Science and engineering Northeastern University

A robust adaptive control is proposed for a class of uncertain nonlinear non-affine SISO systems. In order to approximate the unknown nonlinear function, an affine type neural network(ATNN) and neural state feedback compensation are used, and then to compensate the approximation error and external disturbance, a robust control term is employed. By Lyapunov stability analysis for the closed-loop system, it is proven that tracking errors asymptotically converge to zero. Moreover, an observer is designed to estimate the system states because all the states may not be available for measurements. Furthermore, the adaptation laws of neural networks and the robust controller are given based on the Lyapunov stability theory. Finally, two simulation examples are presented to demonstrate the effectiveness of the proposed control method. Finally, two simulation examples show that the proposed method exhibits strong robustness, fast response and small tracking error, even for the non-affine nonlinear system with external disturbance, which confirms the effectiveness of the proposed approach.

关键词： adaptive control neural networks uncertain non-affine systems state feedback Lyapunov stability

Relativistic density functional investigation of UX_6(X=F,Cl,Br and I)

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Chinese Physics B 2010年第3期19卷 274-280页

作者：张云光李育德 school of Electronics and information engineering Sichuan University

The molecular structures and the vibrational frequencies of uranium hexahalides UX6 （X=F, Cl, Br and I） molecules are investigated by using local density approximation （LDA） and generalised gradient approximation （GGA） functions （BP, BLYP and RPBE） in combination with two different relativistic methods （scalar and scalar＋spin-orbit relativistic effects）. The calculated results show that the differences are trivial between scalar and scalar＋spin-orbit relativistic methods. The vibrational frequencies are also compared with existing experimental values, and overall, the RPBE approach gives the smallest error. The bond dissociation energies （BDEs） of UX6 are computed by using the RPBE function, thereby obtaining exact vibrational frequencies. In addition, the calculated magnitudes of the spin orbit effect on the BDE of UX6 （X=F, Cl, Br, and I） are found to be approximately -0.3198, 0.3218, -0.3609 and -0.4415 eV, respectively.

关键词： molecular structure vibrational frequencies bond dissociation energy spin-orbit cou-pling

Effects of rapid thermal annealing on the room-temperature NO_2-sensing properties of WO_3 thin films under LED radiation

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Chinese Physics B 2013年第6期22卷 615-620页

作者：胡明贾丁立刘青林李明达孙鹏 school of Electronics and information engineering Tianjin University

WO3 thin films were sputtered onto alumina substrates by DC facing-target magnetron sputtering. One sample was rapid-thermal-annealed （RTA） at 600 ℃ in a gas mixture of N2：O2 = 4 ： 1, and as a comparison, another was conventionally thermal-annealed at 600 ℃ in air. The morphology of both was investigated by scanning electron microscopy （SEM） and atomic force microscopy （AFM）, and the crystallization structure and phase identification were characterized by X-ray diffraction （XRD）. The NO2-sensing measurements were taken under LED light at room temperature. The sensitivity of the RTA-treated sample was found to be high, up to nearly 100, whereas the sensitivity of the conventionally thermal-annealed sample was about five under the same conditions. From the much better selectivity and response-recovery characteristics, it can be concluded that compared to conventional thermal annealing, RTA has a greater effect on the NO2-sensing properties of WO3 thin films.

关键词： gas sensor tungsten-oxide thin film rapid thermal annealing LED

Fuzzy Static Output Feedback H_∞ Control for Nonlinear Systems Subject to Parameter Uncertainties

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Journal of Systems Science & Complexity 2018年第2期31卷 343-371页

作者： ZHAO Tao DIAN Songyi school of Electrical engineering and information Sichuan University

This study is concerned with the stabilization issue of nonlinear systems subject to parameter uncertainties. An interval type-2 T-S fuzzy model is used to represent the nonlinear systems subject to parameter uncertainties. An interval type-2 fuzzy static output feedback controller is designed to synthesize the interval type-2 T-S fuzzy systems. The membership-function-dependent stability conditions are derived by utilizing the information of upper and lower membership functions. The proposed stability conditions are presented in the form of linear matrix inequalities（LMIs）. LMI-based stability conditions for interval type-2 fuzzy static output feedback H_∞ control synthesis are also *** simulation examples are given to show the superiority of the proposed approach.

关键词： Interval type-2 fuzzy controller parameter uncertainties static output feedback control T-S fuzzy systems.

Exploring multiamplitude voltage modulation to improve spectrum efficiency in low-complexity visible-light communication

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Science China(information Sciences) 2019年第8期62卷 56-74页

作者： Xiangyu LIU Xuetao WEI Lei GUO Yejun LIU school of Computer Science and engineering Northeastern University school of information Technology University of Cincinnati school of Communication and information engineering Chongqing University of Posts and Telecommunications

Owing to the recent advancements in the Internet of Things(IoT), an increasing number of IoT devices have led to frequency crowding in wireless networks. The low-complexity visible light communication(VLC) system is a promising solution for indoor frequency-crowded wireless networks owing to the ubiquity of light-emitting diodes(LEDs) and readily deployable, low-cost modulation methods. However, due to the inherent limitations of LED materials and growth of data from IoT applications, low-complexity VLC systems can barely boost the data throughput without adding complex modulations and circuits. This study aims to design and implement a spectrum-efficient, low-complexity VLC system to improve data throughput with very little cost to support indoor IoT applications. This system uses multiamplitude voltage to transmit multiple bit streams simultaneously, making it a novel system. However, it is not trivial to achieve this goal as the varying voltage can cause the LEDs to flicker. Therefore, we further propose a voltage-to-current amplifier circuit, which effectively mitigates the effects of changes in the LED’s brightness upon human eyes. Finally, we evaluate the system under different speeds, distances, and angles. Extensive experiments demonstrate promising results from the viewpoint of spectrum efficiency, throughput, bit-error rate, and user perception.

关键词： visible light communication amplitude modulation spectral efficiency

Complex transient dynamics of hidden attractors in a simple 4D system

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Chinese Physics B 2015年第5期24卷 270-274页

作者：党小宇李春彪包伯成武花干 College of Electronic and information engineering Nanjing University of Aeronautics and Astronautics school of Electronic & information engineering Nanjing University of Information Science & Technology school of information Science and engineering Changzhou University school of Electronic and Optical engineering Nanjing University of Science and Technology

A simple four-dimensional system with only one control parameter is proposed in this paper. The novel system has a line or no equilibrium for the global control parameter and exhibits complex transient transition behaviors of hyperchaotic attractors, periodic orbits, and unstable sinks. Especially, for the nonzero-valued control parameter, there exists no equilibrium in the proposed system, leading to the formation of various hidden attractors with complex transient dynamics. The research results indicate that the dynamics of the system shows weak chaotic robustness and depends greatly on the initial states.

关键词： transient dynamics hidden attractor equilibrium

POA-FPRMs: Power Optimization Approach of Fixed Polarity Reed-Muller Expressions for Incompletely Specified Boolean Functions

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Chinese Journal of Electronics 2019年第6期28卷 1144-1151页

作者： HE Zhenxue XIAO Limin HUO Zhisheng WANG Chao LIU Jia WANG Xiang school of information Science and Technology Hebei Agricultural University school of Computer Science and engineering Beihang University school of Electronic and information engineering Beihang University

Fixed polarity Reed-Muller(RM) expression(FPRM) has several practical applications due to its multitude of properties. In order to generate an FPRM with minimum power, based on a genetic algorithm, we propose a Power optimization approach(POA-FPRMs) of Fixed Polarity RM expressions for incompletely specified Boolean functions. Simulation results on MCNC benchmark circuits show that POAFPRMs can effectively reduce power, compared with the traditional polarity optimization approach, where the don’t care terms are neglected.

关键词： Fixed polarity Reed-Muller(RM) expression(FPRM) Genetic algorithm Power optimization Boolean functions

Realistic Cosmetic Plastic Surgery Simulation Based on the Golden Ratio

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Chinese Journal of Electronics 2016年第5期25卷 886-891页

作者： LI Jianfeng LIAO Shenghui LU Rongbo TENG Juan LUO Xiong ZOU Beiji College of information Science and engineering Jishou University school of information Science and engineering Central South University

Facial cosmetology is usually operated by surgeons on the basis of clinical experiences and is full of risks because of the lack of objective criteria and auxiliary tools. The available plastic simulation systems are not easy to manipulate. This paper presents a realistic cosmetic plastic surgery simulation framework guided automatically by golden ratio data, which is suitable for personalized realistic facial models from 3D laser scan. A golden ratio facial mask is made based on the ideal golden ratio facial mask data, with reference to the facial ratio of goodlooking groups of eastern people. The plastic design for the region of interest will be driven automatically by Laplacian coordinates deformation, based on the matched characteristic points and lines of the golden ratio facial mask to set the boundary conditions. The evaluation from clinical surgeons shows that the new plastic simulation system is practical and will be widely used in clinical operations.

关键词： Cosmetic plastic surgery Golden ratio Facial mask Laplacian deformation

Recoverability analysis of block-sparse representation

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Journal of Systems engineering and Electronics 2014年第3期25卷 373-379页

作者： Yuli Fu Jian Zou Qiheng Zhang Haifeng Li school of Electronic and information engineering South China University of Technology school of information and Mathematics Yangtze University

Recoverability of block-sparse signals by convex relaxation methods is considered for the underdetermined linear model. In previous works, some explicit but pessimistic recoverability results which were associated with the dictionary were presented. This paper shows the recoverability of block-sparse signals are associated with the block structure when a random dictionary is given. Several probability inequalities are obtained to show how the recoverability changes along with the block structure parameters, such as the number of nonzero blocks, the block length, the dimension of the measurements and the dimension of the block-sparse representation signal. Also, this paper concludes that if the block-sparse structure can be considered, the recoverability of the signals wil be improved. Numerical examples are given to il ustrate the availability of the presented theoretical results.

关键词： block-sparsity recoverability mixed l2/l1-optimization program.

Dynamic Balance Control Based on an Adaptive Gain-scheduled Backstepping Scheme for Power-line Inspection Robots

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IEEE/CAA Journal of Automatica Sinica 2019年第1期6卷 198-208页

作者： Songyi Dian Lin Chen Son Hoang Ming Pu Junyong Liu the school of Electrical engineering and information Sichuan University the College of Control engineering Chengdu University of Information Technology

This paper presents an adaptive gain-scheduled backstepping control(AGSBC) scheme for the balance control of an underactuated mechanical power-line inspection(PLI) robotic system with two degrees of freedom and a single control ***, a nonlinear dynamic model of the balance adjustment process of the PLI robot is constructed, and then the model is linearized at a nominal equilibrium point to overcome the computational infeasibility of the conventional backstepping technique. Second, to solve generalized stabilization control issue for underactuated systems with multiple equilibrium points,an equilibrium manifold linearized model is developed using a scheduling variable, and then a gain-scheduled backstepping control(GSBC) scheme for expanding the operational area of the controlled system is constructed. Finally, an adaptive mechanism is proposed to counteract the impact of external disturbances. The robust stability of the closed-loop system is ensured by Lyapunov theorem. Simulation results demonstrate the effectiveness and high performance of the proposed scheme compared with other control schemes.

关键词： Adaptive backstepping balance control gain-scheduled inspection robot power line