We study the propagation of one-dimentional optical beams in a weakly nonlocal medium exhibiting cubic-quintic nonlinearity. A nonlinear equation governing the evolution of the beam intensity in the nonlocal medium allows us to examine whether the traveling-waves exist in such optical material. An efficient transformation is applied to obtain explicit solutions of the envelope model equation in the

The paper proposed a model of a locally resonant (LR) piezoelectric/elastic phononic crystal (PC) nanobeam with periodically attached “spring-mass” resonator and additional spring between upper and lower nanobeams, as well as horizontal spring between mass and foundation. Euler beam theory and nonlocal piezoelectricity theory are coupled and introduced to plane wave expansion (PWE) method to calculate

Focused on the hydraulic factor-induced ultra-low frequency oscillation phenomenon happened in a large hydropower plant, this paper investigates the precise modelling of hydraulic transient characteristics in its complex tailrace system and reveals the feasible oscillation suppression schemes from the source side. Combining telegraphist's equations with Saint-Venant equations, the mathematical expression

Although Bayesian approaches have been utilized in engineering systems for health prognostics, very little work has been done using Bayesian methods for fault prediction of systems under multiple attributes. To address this issue, in this paper a novel multi-attribute Bayesian control chart is presented for predicting failures of hidden-state systems by jointly considering two performance measures

It is an important embodiment of fighter's comprehensive ability to have high maneuverability. Therefore, it is necessary to study the coupling dynamic behavior of rotor system in typical maneuvering flight. Based on the finite element method, a 6-node rotor-bearing-disk system model with three kinds of maneuvering loads, nonlinear contact force of rolling bearing, eccentric unbalanced force of disk

Neodymium magnets are the strongest type of permanent magnet commercially available. This investigation aims to numerically study the behavior of ferrofluids in the presence of block neodymium magnets which could be used in a wide range of applications. The problem formulation is derived using the principles of ferrohydrodynamics (FHD) and magnetohydrodynamics (MHD), and the finite volume method is

In this study, a maximum volume sampling model is proposed to improve the accuracy and efficiency of reliability computation. An ellipsoid is constructed with the maximum volume approach in a safe domain, and a new maximum volume optimization method is proposed. The sampling model only computes the samples outside the ellipsoid, which considerably enhances computational efficiency. Furthermore, the

Increasing studies have highlighted that the remarkable inherent uncertainty in design flood hydrograph (DFH) can potentially undermine flood management decisions. In order to quantitatively trace the propagation of DFH uncertainty in reservoir flood control system, we propose a novel methodological framework including three corn parts. First, a copula-based DFH estimation model integrating Bayes’

A novel least squares twin support vector regression method is proposed based on the robust L1-norm distance to alleviate the negative effect of traffic data with outliers. Although there is some known work for the short-term traffic flow prediction problems, their efficacy depends heavily on the collected traffic data, which are often affected by various external factors (e.g. weather, traffic jam

In this paper, we propose an adaptive procedure, recently developed for fractional ordinary differential equations, for the solutions of time–fractional advection–diffusion-reaction equations involving the Caputo derivative. We focus on the adaptivity of the discretization in time direction defining a step size selection function that allows adapting the time step size according to the local behaviour

We analyse the time-series evolution of the cumulative number of confirmed cases of COVID-19, the novel coronavirus disease, for some African countries. We propose a mathematical model, incorporating non-pharmaceutical interventions to unravel the disease transmission dynamics. Analysis of the stability of the model’s steady states was carried out, and the reproduction number R0, a vital key for flattening

This paper presents a bi-directional N-type locally-active memristor (LAM) model, which has two symmetrical locally-active regions with respect to the origin. For this memristor, the locally-active regions coincide with the edge of chaos regimes, where complex dynamic behaviors may occur. By deriving the small-signal admittance of the memristor, it is found that the LAM may be pure resistive, inductive

A new non-semisimple Lie algebra ĝ is constructed. Based on the Lie algebra ĝ, we propose a method for generating ZNɛ integrable couplings. Then, we consider the application of a MKdV isospectral and an AKNS nonisospectral problem of the method respectively. By solving the zero curvature equation of the two spectral problems, we obtain a ZNɛ isospectral MKdV integrable coupling hierarchy and a ZNɛ

In this manuscript we show that a noise-activated escape phenomenon occurs in closed Hamiltonian systems. Due to the energy fluctuations generated by the noise, the isopotential curves open up and the particles can eventually escape in finite times. This drastic change in the dynamical behavior turns the bounded motion into a chaotic scattering problem. We analyze the escape dynamics by means of the

In recent experimental studies, cardio-respiratory synchronization was observed when the respiration rate was higher than the resting heart rate. Under this condition, there is a strong asymmetry in the synchronization tongue towards frequencies higher than that of an unperturbed self-oscillator. These experimental results are compelling because they support a novel hypothesis about the interaction

We consider the exact rogue periodic wave (rogue wave on the periodic background) and periodic wave solutions for the Chen–Lee–Liu equation via the odd-th order Darboux transformation. Then, the multi-layer physics-informed neural networks (PINNs) deep learning method is applied to research the data-driven rogue periodic wave, breather wave, soliton wave and periodic wave solutions of well-known Chen–Lee–Liu

Tri-stable magneto-piezoelastic oscillators exhibit superior performance in terms of broadband resonance frequency and lower excitation threshold, compared to linear and bi-stable systems. Furthermore, inclusion of magnets renders them applicable, tunable, and simple designs. However, the potential of this oscillators for the purpose of simultaneous vibration suppression and energy harvesting has not

Clinical studies using a capacitive micromachined ultrasound transducer (CMUT) at a high rang of frequency in ultrasonic imaging have encouraged researchers to delve into all aspects of this new technology. CMUTs are used as energy converters between electrical and mechanical domains. So, in this paper, the equivalent circuit model of a capacitive micromachined ultrasound transducer is analyzed in

Pure-quartic solitons (PQSs) with higher energy in short pulse width have been generated in the mode-locked fiber laser recently, and soliton molecules have been found as a means to improve the communication capacity of the optical fiber, which has attracted much attention. In this paper, we consider the fourth-order nonlinear Schrödinger equation (FNLSE) derived from Lakshmanan-Porsezian-Daniel equation

This paper develops a novel analytical framework for system kinematic reliability sensitivity analysis of robotic manipulators, which can provide the analytical results of local and global reliability sensitivity defined on the pose and position errors. First, uncertainty analysis of the pose error of the end-effector is accomplished by virtue of the second-order closed-form error propagation formula

Clonorchiasis is a serious food borne parasitic disease caused by clonorchis sinensis that is transmitted via snails to freshwater fish, and then to humans and other mammals. Based on the life cycle clonorchis sinensis, we present a mathematical model of clonorchiasis with three time delays which represent the maturation period of metacercaria developing adult flukes within human host, the period of

In this paper, we propose an efficient numerical scheme for the Allen–Cahn equations. We show theoretically using the Galerkin method and the compactness theorem that the solution of the afore-mentioned equation exists and is unique in appropriate spaces with the interaction length parameter α well controlled. We further, show numerically that the proposed scheme is stable and converge optimally in

In this paper, a problem of the analysis of the randomly forced patterns in spatially distributed systems with diffusion is considered. For the approximation of mean-square deviations of random solutions from the unforced deterministic pattern-attractors, we suggest a constructive method based on the stochastic sensitivity technique. To demonstrate an efficiency of this method, we consider the Levin-Segel

To solve the design problems of engineering structures with multiple conflicting performance indices under uncertainties, a non-probabilistic optimization model which takes into consideration the correlation of uncertainties was proposed in this paper. The multidimensional parallelepiped model was utilized to describe the uncertainties and deal with their correlation. Further, a novel concept of feasible

In this paper, we investigate the stability analysis for interconnected system, which is composed of multiple subsystems with sampled-data control and state quantization. The controlled interconnected system is modeled as a time-delay system with time-varying delays. By employing the information of sampling instants, a discontinuous Lyapunov functional is constructed. Using this functional, we derive

This paper investigates the design of adaptive tracking neural controllers for first- and second-order nonlinear multi-agent periodic time-varying systems described based on random differential equations, respectively. First, the Fourier series expansion and neural networks are used as the main tools to describe the nonlinear periodic disturbance dynamics of the follower, which transforms the completely

This study addresses a healthcare facility location/network design problem considering equity and accessibility. Locating the healthcare facilities, planning the capacity of healthcare facilities, and designing the transfer network are the primary goals of the given problem. The presented model aims to minimize system costs, maximize accessibility, and minimize inequality among all demand nodes. A

In practice, the processes of degradation of inductive components and produced have long-range dependence characteristic, whereby the future degradation evolution is related to both current and previous states. Most known prediction models consider the degradation increments independent and the long-range dependence is not reflected. On the contrary, the heavy tail model can reveal the long-range dependence

Magnetization switching in ferromagnetic structures is an important process for technical applications such as data storage in spintronics, and therefore the determination of the corresponding switching rates becomes essential. We investigate a free-layer system in an oscillating external magnetic field resulting in an additional torque on the spin. The magnetization dynamics including inertial damping

Boolean chaos generated by autonomous Boolean networks has been successfully applied to random number generation, physical unclonable function, gene regulation and reservoir computing, because it can generate complex dynamics with very simple structure. Influences of noise on autonomous Boolean networks chaotic system in delay time parameter spaces are analyzed by simulation and experiments in this

Autapse is introduced as a self-feedback connection that connects the dendrites and axons of the same neuron. Previous studies have revealed that the existence of the autapse can influence the synchronized behaviours of the coupled neurons. In this paper, the chimera state is studied in the presence of autaptic connections. To this aim, a regular network of Hindmarsh-Rose neurons with electrical synapses

The buckling responses of the micro-components show size dependency. The general strain gradient theory is applied to explain the size effects. In this paper, we derive the theoretical relations among the classical couple stress theory, the modified couple stress theory and the general theory. The general theory includes all strain gradients and can respectively reduce to the classical couple stress

We study a novel chemical tanker port call optimization framework to improve the efficiency of waterway traffic control, in which chemical tankers load and unload cargoes while visiting multiple terminals. We formulate this problem as a mixed-integer program to minimize the total cost of vessel operations while compressing the schedule of cargo operations. The port call optimization framework integrates

This work presents a high-order Bernstein-Bézier finite element (FE) discretisation to accurately solve time harmonic elastic wave problems on unstructured triangular mesh grids. Although high-order FEs possess many advantages over standard FEs, the computational cost of matrix assembly is a major issue in high-order computations. A key ingredient to address this drawback is to resort to low complexity

The high-precision estimation of a multimodal probability density function is a difficult problem in many engineering fields. We propose a new method to improve the estimation accuracy based on the fractional moment-based maximum entropy method with a nonlinear transformation and a multi-peak recognition method. For the translation parameters in the nonlinear transformation, three approaches, such

In this article the dynamic buckling behaviour of parametrically excited delaminated composite beam structures are investigated using a two-dimensional finite element discretised planar model. To reduce the complexity of the numerical model and to be able to maintain the desired accuracy of the whole system the so called Craig-Bampton fixed interface model reduction technique is extended. The main

Body-in-white (BIW) is a typical frame structure formed by a great many thin-walled structures, and the optimal design of its lightweight and crashworthiness is a typical nonlinear dynamic response optimization problem with multiple design variables. Here, we propose a thickness-based subdomain hybrid cellular automata (T-SHCA) algorithm to solve the lightweight design of BIW under side collision,

Second-order photonic topological insulators (SPTIs) featured with topological edge and corner states provide an intriguing way for steering light in integrated optics. However, existing SPTIs have narrow bulk gaps for tightly confining topological edge and corner states. In this paper, we propose a bi-directional evolutionary structural optimization (BESO) method to inversely engineer SPTIs in C3-symmetric

This paper considers a variational model for single image blind restoration. By exploiting the fractional-order total variation (FTV) and Lp quasinorm relaxation, a non-convex fractional-order variational model is proposed to restore the image blurred by an unknown blur kernel. A quaternion FTV model is first put forward to exploring more directional information of an image. The new model utilizes

This is a paper in the intersection of time series analysis and complexity theory that presents new results on permutation complexity in general and permutation entropy in particular. In this context, permutation complexity refers to the characterization of time series by means of ordinal patterns (permutations), entropic measures, decay rates of missing ordinal patterns, and more. Since the inception

A fully finite element approximation of the Keller–Segel model, including self- and cross-diffusion terms and a logistic source, has been considered. The existence of a fully finite element approximation of the Keller–Segel model, some stability bounds of the solution and the convergence of the approximated solution have been shown. As a result, the existence of a solution to the nonlinear Keller–Segel

Multiple viral infection is an important issue in health and agriculture with strong impacts on society and the economy. Several investigations have dealt with the population dynamics of viruses with different dynamic properties, focusing on strain competition during multiple infections and the effects on viruses’ hosts. Recent interest has been on how multiple infections respond to abiotic factors

Approximation theory plays an important role in image processing, especially image deconvolution and decomposition. For piecewise smooth images, there are many methods that have been developed over the past thirty years. The goal of this study is to devise similar and practical methodology for handling textured images. This problem is motivated by forensic imaging, since fingerprints, shoeprints and

In this paper, a phase-field-based lattice Boltzmann model for ternary fluid flows is proposed, where the conservative Allen-Cahn equation for ternary fluids is employed to track the interface of fluids. A time derivative term is introduced to the LB equation for the conservative Allen-Cahn equation and a forcing distribution function is used to the LB equation for the Navier-Stokes equations. The

An improved mesh stiffness calculation model of helical gear pair is proposed, in which the transverse gear tooth stiffness, transverse gear foundation stiffness, in addition to axial gear tooth stiffness, axial gear foundation stiffness, that influenced by surface roughness under elastohydrodynamic lubrication (EHL) condition are fully considered. The time varying friction coefficients are obtained

Accurate evaluation of preload in system with double-bolted connections is critical for the service performance of engineering structures or equipment. However, the theoretical framework for assessing preload is imperfect. An equivalent approach from the tightening process of double-bolted joints to second-order spectral problem of the energy-dependent potential is firstly established. This paper proposes

The storage and distribution of medical supplies are important parts of epidemic prevention and control. This paper first proposes a new nonsmooth two-stage stochastic equilibrium model of medical supplies in epidemic management. The first stage addresses the storage in the pre-disaster phase, and the second stage focuses on the dynamic distribution by enrolling competitions among multiple hospitals

The adequate coupling of dissimilar materials and structural element types provides effective engineering designs. Particularly, it enables high stiffness and low weight mechanical components, which are largely desired in numerous applications. Besides, Isogeometric Analysis (IGA) has recently stood out as a robust and accurate approach for the mechanical modelling of complex 3D engineering designs

We explore the dynamical properties of transformed nonlinear waves (TNWs) for the (3+1)-dimensional B-type Kadomtsev–Petviashvili (BKP) equation describing the propagation of waves in fluids. The breath-wave solution is first given by the Hirota bilinear method. Different from the (1+1)- or (2+1)-dimensional case, three types of conversion conditions are analytically derived in different spatial coordinates

The stability and hopf bifurcation of the multi-lingual rumor spreading model are mainly studied in this paper. A nonlinear inhibition mechanism is introduced to formulate an IS2R2 model with concerning the cross propagation in the multi-lingual environment. Next, the existence and stability of equilibrium points are analyzed systematically here. Meanwhile, choosing the key parameter and time delay

The main purpose of the proposed work is to study a TB infection model under incomplete treatment numerically and identify potential infection dynamics. We use the arbitrary-order Caputo-Fabrizio (CF) and Atangana-Baleanu (AB) derivatives to extend the classical TB infection model into a non-classical model. In addition, through fixed-point results, the existence and uniqueness of solutions for the

With increased longevity in a nowadays society, Alzheimer’s disease (AD), an incurable neurodegenerative disease, becomes a serious threat to human health. To address the challenges to understanding and predicting AD development and treatment, we focus on the development of a stochastic reaction-diffusion model with time-varying delay and impulsive perturbations, which is driven by Le´vy jump process

The volume of fluid (VOF) method combined with the adaptive grid method is used to study the influence of shear-thinning liquid viscosity ratio (ε=μ0/μ∞) for various values of rheological index (n) and characteristic time (λ) on bubble shape, rise velocity, and apparent viscosity around a bubble; where 1/λ represents the shear rate at which the change in the viscosity curve occurs from the low shear