查看更多>>摘要：In this work, we analyse the study of neutral fractional differential equation in an arbitrary Hilbert space. An as-sociated integral equation is studied , approximate integral equation is obtained. We demonstrate the exis-tence and uniqueness of an approximate solution by using analytic semigroup theory and the Fixed point method. In the application part, we discuss the approximation and the convergence results for such an approx-imation. (c) 2022 Elsevier Ltd. All rights reserved.
查看更多>>摘要：We study the effect of finite driving by the time-varying external magnetic field in the two-dimensional disordered ferromagnetic systems portrayed on the case of nonequlibrium athermal random field Ising model. The response of studied systems is rate-dependent exhibiting scaling and data collapsing above the dynamical critical point in the full range of driving rates provided that the system parameters satisfy both the finite-size and here introduced rate-dependent scaling conditions. These findings are based on extensive numerical simulations of large systems reliably demonstrating the observed behavior and could be relevant for real thin systems driven at finite rates.(c) 2022 Elsevier Ltd. All rights reserved.
查看更多>>摘要：Species migration is one of the common features in ecological science, and movement between different environments can affect the sustainability or maintenance of communities. In this paper, we investigate how external migration of species that can explain inter-patch migration can affect the biodiversity of cyclically competing species. Through the coupling between the two deterministic systems of cyclic competition governed by rock paper-scissors game, we found the emergence of synchronization between attractors that could explain the different characteristics of coexistence states. In addition, these functions may appear to be complete or quasi synchronized depending on the synergistic effect. Since the coupling can explain the migration between two systems in distinct patches, the results can provide an insight into the collective behavior of the population from the perspective of ecological and social sciences.(c) 2022 Elsevier Ltd. All rights reserved.
查看更多>>摘要：In this paper, the dynamic characteristics of a class of fractional cubic nonlinear systems are studied. Firstly, the analytical expressions of amplitude-frequency relationship of forced vibration system are obtained by means of average method, and then compared with the numerical solutions defined by Grunwald-Letnikov fractional differential. Secondly, the amplitude-frequency characteristic curves of the forced vibration system under different fractional orders, external excitation amplitude, cubic stiffness and fractional differential terms were investigated respectively. Thirdly, the amplitude-frequency and phase-frequency characteristics of self-excited vibration system under different fractional orders are investigated. Finally, the fork bifurcation behavior of the system under different external excitation amplitudes, cubic damping and fractional differential terms is analyzed. In addition, the change of equilibrium point caused by fractional order under different fractional differential terms and cubic damping and the saddle node bifurcation caused by the change of cubic damping parameters are also analyzed.(c) 2022 Elsevier Ltd. All rights reserved.
查看更多>>摘要：In this paper, we introduce the inertial Mann forward-backward splitting algorithm for solving variational inclusion problem of the sum of two operators, the one is maximally monotone and the other is monotone and Lipschitz continuous. Under standard assumptions, we prove the weak convergence theorem of the proposed algorithm. We show that the algorithm is flexible to use by choosing the variable stepsizes and two different algorithms are shown by choosing constant stepsize and update stepsize. Moreover, we apply our algorithms to solve data classification using the Wisconsin original breast cancer data set as a training set. We also compare our algorithms with the other two algorithms to show the efficiency of the algorithm and show suitably learns the training dataset and generalizes well to a hold-out dataset of the algorithm by considering overfitting. Finally, we apply our algorithms to solve signal recovery and show the efficiency of the algorithm by compare with the other two algorithms. The results of data classification and signal recovery showed that choosing the right stepsizes of the algorithm would be a good efficient for the different problems. (c) 2022 Elsevier Ltd.
查看更多>>摘要：The main aim of this paper is to analyze the modified epidemiological Susceptible-Infected-Removed model in-cluding an antidotal population compartment A (SIRA). The fractional natural decomposition method (FNDM) and variational iteration method (VIM) are applied to the governing model. This model is used to explain the wave behaviors of the infection virus arising in computer science. The SIRA model uses the Caputo derivative sat-isfying the initial conditions. Moreover, numerical investigations and strain conditions for the optimal values of parameters to minimize the effect of computer virus are also reported. The Lipschitz condition theorem and the Banach space are considered to present the uniqueness with the Caputo operator. Furthermore, various wave distributions of the nature of virus's are also extracted in plots.(c) 2022 Elsevier Ltd.
查看更多>>摘要：The chaotic system with complicated dynamical behaviors has high potential in practical applications. This paper reports a simple smooth 3D dynamical system that is derived from the Nose-Hoover oscillator and has rich dynamical behaviors, such as fold-Hopf bifurcation, saddle-node bifurcation, transient chaos, and conservative chaos (hidden attractors), which respectively correspond to four cases of equilibrium: infinitely many equilibria, two equilibria, four equilibria and no equilibrium. We first concentrate on the theoretical investigation of degenerate fold-Hopf and saddle-node bifurcations. Then, the power-law distribution of average lifetime of transient chaos is calculated and the coexistence of steady state and periodic motion after transient chaos is partially exhibited by time series. For the case of no equilibrium, we further study the conservative and ergodic dynamics, and hidden attractors with extremely rare properties by time-domain waveforms, phase portraits, histograms and Poincare sections. Finally, the FPGA-based experimental results are presented and they are consistent with the numerical simulation results.
查看更多>>摘要：In the present paper, we study the distribution of the return points in the fibers for a random nonuniformly expanding dynamical system, preserving an ergodic probability. We also show the abundance of nonlacunarity of hyperbolic times that are obtained along the orbits through the fibers. We conclude that any ergodic measure with positive Lyapunov exponents satisfies the nonuniform specification property among fibers. As consequences, we prove that any expanding measure is the limit of probability measures whose measures of disintegration on the fibers are supported on a finite number of return points and we prove that the average of the measures on the fibers corresponding to a disintegration, along the orbit (theta(n)(w))(n >= 0) in the base dynamics is the limit of Dirac measures supported on return orbits on the fibers. (C) 2022 Elsevier Ltd. All rights reserved.
查看更多>>摘要：The phenomenon of noise-induced transition driven by the correlated Gaussian and non-Gaussian colored noises is investigated by the first escape probability (FEP) and the mean first exit time (MFET). To derive the Markovian approximation of the original tumor growth model and obtain the analytical expressions of the FEP and MFET, we reduce the non-Gaussian colored noise and then expand the unified colored noise approximation (UCNA). Additionally, the stochastic basin of attraction (SBA), a recent geometric concept based on the FEP and MFET, is introduced to provide further insight into the effects of noisy fluctuations on the basin stability of a certain domain. A higher FEP or shorter MFET in the high tumor population region B facilitates the transition from B to the low tumor population region Bc, which indicates the weaker stability of domain B . Our main results demonstrate that (i) the transitions from B to Bc can be induced by both the Gaussian and non-Gaussian noise sources; (ii) the stronger noise intensity, especially the non-Gaussian noise intensity, with a larger deviation parameter and immune coefficient improves the FEP, shortens the MFET, and hence benefits the transitions. However, the enlargement of the correlation between noises strengthens the basin stability of domain B and impedes the transitions; (iii) the size of SBA expands due to the larger cross-correlated intensity. In contrast, the enhancements of noise intensities with a larger departure degree reduce the size of SBA, which weakens the basin stability and is less in favor of tumor treatment. Furthermore, the Monte Carlo simulations of the original system are employed to verify the feasibility and accuracy of the analytical predictions. (C) 2022 Elsevier Ltd. All rights reserved.
查看更多>>摘要：This paper deals with the cluster analysis of selected countries based on COVID-19 new deaths per million data. We implement a statistical procedure that combines a rank-size exploration and a k-means approach for clustering. Specifically, we first carry out a best -fit exercise on a suitable polynomial rank-size law at an individual country level; then, we cluster the considered countries by adopting a k-means clustering procedure based on the calibrated best -fit parameters. The investigated countries are selected considering those with a high value for the Healthcare Access and Quality Index to make a consistent analysis and reduce biases from the data collection phase. Interesting results emerge from the meaningful interpretation of the parameters of the best -fit curves; in particular, we show some relevant properties of the considered countries when dealing with the days with the highest number of new daily deaths per million and waves. Moreover, the exploration of the obtained clusters allows explaining some common countries' features.(c) 2022 Elsevier Ltd. All rights reserved.
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