Publications

Bifurcations of Traveling Wave Solutions for Fully Nonlinear Water Waves with Surface Tension in the Generalized Serre–Green–Naghdi Equations

For the generalized Serre–Green–Naghdi equations with surface tension, using the methodologies of dynamical systems and singular traveling wave theory developed by Li and Chen [2007] for their traveling wave systems, in different parameter conditions of the parameter space, all possible bounded solutions (solitary wave solutions, kink wave solutions, peakons, pseudo-peakons and periodic peakons as well as compactons) are obtained. More than 26 explicit exact parametric representations are given. It is interesting to find that this fully nonlinear water waves equation coexists with uncountably infinitely many smooth solitary wave solutions or infinitely many pseudo-peakon solutions with periodic solutions or compacton solutions. Differing from the well-known peakon solution of the Camassa–Holm equation, the generalized Serre–Green–Naghdi equations have four new forms of peakon solutions.

Limiting Kalman Filter

No abstract is provided for this article.

Some criteria of chaos in non-autonomous discrete dynamical systems

This paper establishes several criteria for strong Li–Yorke chaos and distributional chaos in non-autonomous discrete dynamical systems. The main criterion of distributional δ-chaos for some δ>0 is induced by weak A-coupled-expansion in a sequence of nonempty compact subsets, where A is an irreducible transition matrix with at least one row sum larger than 1. Some of these results not only extend the existing related results for autonomous discrete systems to non-autonomous discrete systems, but also relax the assumptions of the counterparts. One example of a non-autonomous logistic system is provided for illustration.

Valorization of dual waste: Heavy metal mitigation and carbon/nutrient regulation in hydrochar via co-hydrothermal carbonization of sewage sludge and sawdust

Characterizing uninorms on bounded lattices

This paper establishes some equivalent conditions of a uninorm, extending an arbitrary triangular norm on [0, e] or an arbitrary triangular conorm on [e, 1] to the whole lattice.

Cooperative Time-Varying Formation Fuzzy Tracking Control of Multiple Heterogeneous Uncertain Marine Surface Vehicles With Actuator Failures

This article addresses the cooperative time-varying formation fuzzy tracking control problem for a cluster of heterogeneous multiple marine surface vehicles subject to unknown nonlinearity and actuator failures. The proposed cooperative control scheme consists of two parts: 1) a distributed time-varying formation observer and 2) a decentralized adaptive fuzzy tracking controller. The distributed observer is designed to obtain a predefined time-varying formation pattern under a directed communication topology. Subsequently, based on the states of the distributed observer, a decentralized fuzzy tracking control law is developed using fuzzy-logic systems and the adaptive approach. Lyapunov functions are constructed to guarantee that the controlled marine vehicles attain the desired time-varying formation with asymptotical stability of tracking errors. Finally, simulation results are presented to validate the efficacy of the proposed control methodology.

Approximation in Hardy Spaces

No abstract is provided for this article.

A Kalman filtering technique for certain Markov chains

No abstract is provided for this article.

Diffeomorphisms with infinitely many Smale horseshoes

A class of planar diffeomorphims is formulated, with infinitely many coexisting Smale horseshoes, where the Lebesgue measure of the parameters with such strange dynamics is infinite. On each horseshoe, there exists a uniformly hyperbolic invariant set, on which the map is topologically conjugate to the two-sided full-shift on two symbols. Moreover, the topological entropy is infinite in certain parameter regions.

Controlling Hopf bifurcations: continuous-time systems

Bifurcation control has attracted increasing attention in recent years. A simple and unified state-feedback method is developed in this paper for Hopf bifurcation control for continuous-time systems. The control task can be either shifting an existing Hopf bifurcation or creating a new Hopf bifurcation. Some computer simulations are included to illustrate the method and verify the theoretical results.

Guest Editorial: Special Issue on Learning, Optimization, and Implementation for Circuits and Systems Driven by Artificial Intelligence

No abstract is provided for this article.

A Self-Reproduction Hyperchaotic Map With Compound Lattice Dynamics

In this article, sinusoidal functions are introduced to a discrete map for hyperchaos generation and attractor self-reproduction. The constructed map shares a unique structure with controllable symmetry and conditional symmetry, which exhibits compound lattice dynamics, including 1-D and 2-D attractor growth. The direction of attractor growth can be controlled under polarity balance. STM32-based circuit realization verifies the results with numerical simulation and theoretical analysis. A pseudorandom number generator is built finally based on the newly proposed hyperchaotic map proving the high performance in application.

Synchronization of chaotic systems from a fuzzy regulation approach

In this paper, some results on fuzzy regulation and fuzzy modeling are presented for synchronization of chaotic systems described by Takagi–Sugeno (TS) fuzzy models using linear local controllers. It is shown that the synchronization error is bounded if the local controller can be appropriately designed, and that such an error is independent of initial conditions. This feature allows synchronizing not only similar chaotic systems but, under certain conditions, different chaotic systems can be synchronized as well. In other words, this approach can be used to obtain either complete or generalized synchronization. Several simulations are carried out to illustrate how the problem can be solved in a practical way by using the linear matrix inequalities (LMI) technique.

[A case with type I Crigler-Najjar syndrome].

No abstract is provided for this article.

Controlling the amplitudes of oscillations in nonlinear systems

This paper studies feedback control of limit cycle amplitudes in nonlinear systems. A suitable implementation of the design is developed via an approximation of the time-derivative term in the nonlinear state feedback controller. A classical model is finally simulated for illustration of the proposed control method.

Differentiating complex network models: An engineering perspective

Network models that can capture the underlying network’s topologies and functionalities are crucial for the development of complex network algorithms and protocols. In the engineering community, the performances of network algorithms and protocols are usually evaluated by running them on a network model. In most if not all reported work, the criteria used to determine such a network model rely on how close it matches the network data in terms of some basic topological characteristics. However, the intrinsic relations between a network topology and its functionalities are still unclear. A question arises naturally: For a network model which can reproduce some topological characteristics of the underlying network, is it reasonable and valid to use this model to be a test-bed for evaluating the network’s performances? To answer this question, we take a close look at several typical complex network models of the AS-level Internet as examples of study. We find that although a model can represent the Internet in terms of topological metrics, it cannot be used to evaluate the Internet performances. Our findings reveal that the approaches using topological metrics to discriminate network models, which have been widely used in the engineering community, may lead to confusing or even incorrect conclusions.

A fuzzy logic controller for boiler systems in power plants

This paper describes a fuzzy proportional-integral (PI) controller and its application in boilers control for power plants. First, the fuzzy PI controller is briefly described. Then, some real data simulations for boilers control in power plants are shown to demonstrate its advantages for controlling the temperature of the generator and the boiler feed tank level over the conventional PI controllers that are used in power industries today.

Kalman Filter: An Elementary Approach

No abstract is provided for this article.