Stability of piecewise affine systems with application to chaos stabilization

This paper addresses the stability issue for a class of piecewise affine (PWA) systems, where the state spaces are assumed to be dividable into a certain number of hypercuboid subspaces. By constructing appropriate piecewise continuous Lyapunov functions, several numerically tractable stability criteria are developed for four subclasses of such PWA systems, which allow to recast the switching control problem for the PWA systems as a convex optimization problem. Moreover, the proposed method is applied to switching controller design for (globally and locally) stabilizing the unstable equilibrium points of PWA chaotic systems. Numerical simulations on the chaotic Chua's circuit are presented to verify the theoretical results.     

复杂网络及其新近研究进展简介

简单地介绍了近10年来蓬勃发展的复杂网络研究新领域, 特别是其中最具代表性的随机网络、小世界网络和无尺度网络模型及其基本参数和概念, 并简要地回顾了复杂网络理论在生物和大脑神经网络、流行病传播与免疫控制、交通与社会经济、无线通讯、计算机和互联网、传感器网络、语言学与社会科学以及群体活动和编队飞行问题中的分散控制、稳定性特别是一致性问题等方面的应用趋势.     

4-氟-1,2-二氢-3,6-哒嗪二酮及其衍生物的合成

本文报导了4-氟-1,2-二氢-3,6-哒嗪二酮(Ⅱ)及其衍生物3,6-二氯-4-氟哒嗪(Ⅲ)、3-甲氧基-4-氟-6-氯哒嗪(Ⅳ)、3-邻甲苯氧基-4-氟-6-氯哒嗪(Ⅵ)、1-苯基-3-羟基-4-氟-6-哒嗪酮(Ⅶ)等五种新化合物的合成,探讨了(Ⅲ)同亲核试剂的反应性能和部分化合物的药理实验结果.     

A novel antenna for sub-atmospheric radio-frequency discharge

A novel antenna that can generate plasma efficiently for pressure up to thousands of Pascal with 1 kW–13.56 MHz radio-frequency power supply is reported. It consists of two isolated solenoids so that involves both capacitively coupling and inductively coupling effects, together with magnetic mirror effect which confines the formed plasma axially to a certain extent. Experiments show that the novel discharge has directional preference depending on the applied voltage, a character of dielectric barrier discharge, and can run steadily for tens of hours without severe thermal load. Simulations using COMSOL Multiphysics reveal consistent variations of electron temperature and electron density with base pressure, input power, separation distance of isolated solenoids, and the number of turns of each solenoid. This ionization method is of great interest for plasma processing and propulsion in sub-atmospheric environment.     

An objective method for color vision deficiencies measurement based on visual evoked potential

The equi-luminance of color stimulus in normal subjects is characterized by L-cone and M-cone activation in retina. For the protanopes and deuternopes, only the activations of one relevant remaining cone type should be considered.     

Multifolded torus chaotic attractors: design and implementation

This paper proposes a systematic methodology for creating multifolded torus chaotic attractors from a simple three-dimensional piecewise-linear system. Theoretical analysis shows that the multifolded torus chaotic attractors can be generated via alternative switchings between two basic linear systems. The theoretical design principle and the underlying dynamic mechanism are then further investigated by analyzing the emerging bifurcation and the stable and unstable subspaces of the two basic linear systems. A novel block circuit diagram is also designed for hardware implementation of 3-, 5-, 7-, 9-folded torus chaotic attractors via switching the corresponding switches. This is the first time a 9-folded torus chaotic attractor generated by an analog circuit has been verified experimentally. Furthermore, some recursive formulas of system parameters are rigorously derived, which is useful for improving hardware implementation.     

卤代哒嗪酮氟代反应的研究

前文^[1,2]报道了氟代哒嗪二酮化合物的合成及生理活性,其合成路线较长,收率较低。     

The basin of attraction of the Chen attractor

By geometric analysis, we discuss the riddled property of the basin of attraction of the Chen attractor based on Milnor’s definition, and prove that any neighborhood of the Chen attractor contains repelled sets with positive Lebesque measures. Our analytic and numerical results show that the Chen attractor indeed has some unusual properties leading to a “strange attractor” in the sense of Milnor.     

Naming Game with Multiple Hearers

A new model called Naming Game with Multiple Hearers (NGMH) is proposed in this paper. A naming game over a population of individuals aims to reach consensus on the name of an object through pair-wise local interactions among all the individuals. The proposed NGMH model describes the learning process of a new word, in a population with one speaker and multiple hearers, at each interaction towards convergence. The characteristics of NGMH are examined on three types of network topologies, namely ER random-graph network, WS small-world network, and BA scale-free network. Comparative analysis on the convergence time is performed, revealing that the topology with a larger average (node) degree can reach consensus faster than the others over the same population. It is found that, for a homogeneous network, the average degree is the limiting value of the number of hearers, which reduces the individual ability of learning new words, consequently decreasing the convergence time; for a scale-free network, this limiting value is the deviation of the average degree. It is also found that a network with a larger clustering coefficient takes longer time to converge; especially a small-word network with smallest rewiring possibility takes longest time to reach convergence. As more new nodes are being added to scale-free networks with different degree distributions, their convergence time appears to be robust against the network-size variation. Most new findings reported in this paper are different from that of the single-speaker/single-hearer naming games documented in the literature.     

An optimal linear-quadratic digital tracker for analog neutral time-delay systems

^** Email: shtsai{at}mail.ncku.edu.tw In this paper, an optimal hybrid tracking control problem forcontinuous neutral time-delay systems is formulated and studied.An optimal linear integral quadratic cost function that hasa high-gain property is used for tracking control specification.Two interpolation methods are applied to directly convert theoriginal analog neutral time-delay system into an equivalentdigital retarded time-delay system, and meanwhile convert thecontinuous-time quadratic cost function into a discretized form.Then, an extended state vector is constructed for an associateextended discrete-time optimal control problem without timedelay. Using the standard discrete-time linear-quadratic optimalcontrol theory and an indirect digital redesign technique witha predictive feature, an effective digital tracker is designedfor the original analog neutral time-delay system. An exampleis finally given for illustrating the effectiveness of the newtracker design method.