Publications

Performance and Capacity Analysis of MDCSK-BICM for Impulsive Noise in PLC

To further mitigate the BER error floor of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$M$</tex-math></inline-formula> -ary differential chaos shift keying (MDCSK) modulation for impulsive noise, a low-cost high-reliability coded modulation scheme without equalizations is desirable for impulsive noise. In this paper, a protograph-based low-density parity-check coded MDCSK-based bit-interleaved coded modulation (MDCSK-BICM) scheme is proposed for the scenario with impulsive noise obeying Bernoulli-Laplace distribution. Considering the Gaussian distribution of protograph extrinsic information transfer (PEXIT) and the benchmark of coding design, the U-shaped non-coherent capacity is derived with optimal code rate for square MDCSK, showing that the code rates are stable with <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$E_b/N_0$</tex-math></inline-formula> increasing but still much lower than that of DS-16DQAM at code rate <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$&gt;\!0.145$</tex-math></inline-formula> . The derived joint probability density function can be considered as approximately a Gaussian distribution, which is used to improve the impulsive noise fitted PEXIT. Finally, a new code under a novel principle is designed for better bit error rate performance based on the improved PEXIT analysis. Both PEXIT analysis and simulation results demonstrate that the proposed scheme achieves a better BER than that with a traditional scheme, and suggesting a research approach based on simple methods. This basic research work provides a guide to establish a framework and optimize the performance of transmission systems over practical power line communication.

ON SPATIAL PERIODIC ORBITS AND SPATIAL CHAOS

This paper introduces an analytical method for constructing spatial periodic orbits of specified periods. This result is then extended to generating spatial chaos in the sense of Li and Yorke.

S-Type Locally Active Memristor-Based Periodic and Chaotic Oscillators

S-type locally-active memristor (LAM) has a great potential for brain- inspired neuromorphic computing, where the S-type LAM-based oscillator is a fundamental building block. Concerning the S-type LAM, this paper constructs a material-independent model in simple mathematical expression, which can be relatively easily analyzed. By biasing the memristor into the locally- active region, and connecting it with a capacitor, a second-order oscillator can be built. The small-signal equivalent circuit of the memristor and its frequency response are applied to determine the period oscillation frequency range and compensation capacitance. Hopf bifurcation theory is used to analyze oscillation mechanism of the second-order circuit and appropriate capacitance. By adding an extra inductor into the second-order oscillator, a novel third-order chaotic circuit is developed, where a saddle-focus is derived to create chaos. Its dynamic characteristics are investigated via Lyapunov exponents, bifurcation diagrams, dynamic route map, and so on. The local activities of the single memristor, second-order oscillator, and third-order chaotic circuit are verified through the mathematical analysis. Finally, physical circuit realizations of the S- type LAM-based oscillators, including the memristor emulator, are presented. Both simulation and experimental results demonstrate the practicability of the proposed mathematical model and the validity of the theoretical analysis.

Performance-Guaranteed Finite-Time Tracking of Strict-Feedback Systems with Unknown Control Directions: A Novel Switching Mechanism

The problem of achieving performance-guaranteed finite-time exact tracking for uncertain strict-feedback nonlinear systems with unknown control directions is addressed. A novel logic switching mechanism with monitoring functions is designed to deal with unknown control directions. This approach is different from existing methods like the Nussbaum gain technique and smooth orientation functions, which are inapplicable to finite-time exact tracking. The main challenge lies in designing monitoring functions and determining switching rules, which is well resolved through three steps. Most significantly, in contrast to existing works that solely guarantee bounded tracking or asymptotic exact tracking, the new mechanism incorporates novel integral sliding mode techniques to achieve finite-time exact tracking with guaranteed performance. Finally, simulations are presented with comparison to demonstrate the effectiveness of the proposed methods.

Analysis, control and applications of complex networks: A brief overview

Complex networks are ubiquitous in the world. Many phenomena in nature can be described by the complex networks, such as brain structures, protein-protein interaction networks, scientific citation networks, food web, social interactions, the Internet, and so on. The study of complex networks is a young and active area of scientific research inspired largely by the empirical investigations of many real-world complex networks such as computer networks and social networks. It is very necessary to briefly review the main advances in the analysis, control and applications of complex networks over the last decade.

Estimating the Lyapunov exponents of discrete systems

In the present paper, our aim is to determine both upper and lower bounds for all the Lyapunov exponents of a given finite-dimensional discrete map. To show the efficiency of the proposed estimation method, two examples are given, including the well-known Henon map and a coupled map lattice.

Stabilizing Unstable Equilibria of Chaotic Systems From a State Observer Approach

In this paper, a simple control method is proposed for stabilizing unstable equilibria of two typical classes of chaotic systems. For piecewise-linear chaotic systems, such as Chua's circuit, the control parameters can be selected via the pole placement technique from the linear control theory. For general nonlinear chaotic systems with continuously differentiable nonlinearities, particularly polynomial chaotic systems such as the Ro/spl uml/ssler system, Lorenz system, Chen's system, and the modified Chua's circuit with cubic nonlinearity, the control parameters can be chosen according to the pole placement technique and some additional theories of nonlinear ordinary differential equations. The criteria for the design of the control parameters are also investigated. This method is demonstrated to be highly robust against system parametric variations. To verify the effectiveness of the method, it is applied to both the original and the modified chaotic Chua's circuits, where satisfactory control performance is observed in simulations.

When Structure Meets Function in Evolutionary Dynamics on Complex Networks

Evolutionary dynamics play a fundamental role in exploring the underlying mechanism of collective behaviors over a multi-agent network. Traditionally, evolutionary dynamics focus on the analysis of evolutionary behaviors of unstructured complex systems. However, recent research reveals that system structure is essential in the formation of collective behaviors. This article shows the intrinsic relation between structure and function of a complex dynamical network with evolutionary dynamics. In particular, the impact of node dynamics and network structure on evolutionary dynamics is investigated. Methods are given to find invasion hubs of a network and to design efficient networks for innovation diffusion. Moreover, it discusses some potential real-world applications and highlights some challenging problems for future studies.

IEEE ICCA 2018 Plenary Panel Session: Trends in research on multi-agent systems

Summary form only given, as follows. A complete record of the panel discussion was not made available for publication as part of the conference proceedings. The theme of the IEEE ICCA plenary session this year is Trends in Research on Multi-agent Systems. We are honored that four prominent researchers in our field will join this panel to share their expertise and visions, as well as to discuss about challenges and opportunities, in research on multi-agent systems. Through direct conversation between these world-renowned panelists and other ICCA attendees, we hope to gain a deeper insight into some fundamental and emerging problems in the research area of multi-agent systems and in our general field of control and automation. This panel will also serve as a platform for the audience, in particular students and other junior researchers, to hear the opinions of senior members of our community on issues we often face at the early stage of our career or study.

Chaos in the fractional order Chen system and its control

In this letter, we study the chaotic behaviors in the fractional order Chen system. We found that chaos exists in the fractional order Chen system with order less than 3. The lowest order we found to have chaos in this system is 2.1. Linear feedback control of chaos in this system is also studied.

Distribution of Controlled Lyapunov Exponents via the Lai-Chen Algorithm

The Lai-Chen algorithm, an extended feedback control scheme of the original Chen- Lai algorithm, was proposed to gradually make an arbitrarily given discrete-time dynamical system chaotic in terms of possessing positive Lyapunov exponents with uniformly bounded orbits. In this paper, based on the Monte Carlo method, we further study the distribution of the controlled Lyapunov exponents generated by the Lai-Chen algorithm.

Unraveling the direct effect of cationic methylation on molecular structure, electronic structure, and stability of pentazolate salts in an external electric field

CAN A THREE-DIMENSIONAL SMOOTH AUTONOMOUS QUADRATIC CHAOTIC SYSTEM GENERATE A SINGLE FOUR-SCROLL ATTRACTOR?

Recently, we have investigated a new chaotic system of three-dimensional autonomous quadratic ordinary differential equations, and found that the system visually displays a four-scroll chaotic attractor confirmed by both numerical simulations and circuit implementation. In this paper, we further study the following question: Is it really true that this system can generate a four-scroll chaotic attractor, or is it only a numerical artifact? By a more careful theoretical analysis along with some further numerical simulations, we conclude that the four-scroll chaotic attractor of this system, which we observed on both computer and oscilloscope, cannot actually exist in theory. The fact is that this system has two co-existing two-scroll chaotic attractors that are arbitrarily close in the phase space for some system parameters, therefore extremely tiny numerical round-off errors or signal fluctuations will nudge the system orbit to switch from one attractor to another, thereby forming the seemingly single four-scroll chaotic attractor on screen display.

L_p-Stability of a Class of Volterra Systems

This technical note presents some new and explicit stability results for Volterra systems using two different approaches. The first approach is based on monomial domination of the Volterra system's memoryless output nonlinearity and the second on its Lipschitz-norm. The former yields more widely applicable results, but introduces nonconvexity in the signal spaces to be dealt with for certain parameter values.

Sequential and Square-Root Algorithms

No abstract is provided for this article.

Rational approximation theory and its applications in systems engineering: an overview

This article offers an overview of rational approximation theory and its applications in systems engineering. The importance of rational approximation theory in systems engineering and signal processing can be easily understood from the observation that all the transfer functions (matrices) of linear time-invariant systems and digital filters are rational functions (matrices). Rational approximation has a long history in the field of approximation theory, an important and active branch of mathematics, and has found very broad applications in control and systems engineering.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Controllability of Kronecker Product Networks

A necessary and sufficient condition is derived for the controllability of Kronecker product networks, where the factor networks are general directed graphs. The condition explicitly illustrates how the controllability of the factor networks affects the controllability of the composite network. For the special case where at least one factor network is diagonalizable, an easily-verifiable condition is explicitly expressed. Furthermore, the controllability of higher-dimensional multi-agent systems is revisited, revealing that some controllability criterion reported in the literature does not hold. Consequently, a modified necessary and sufficient condition is established. The effectiveness of the new conditions is demonstrated through several examples.

Introduction to Chaos Control and Anti-Control

No abstract is provided for this article.