共查询到20条相似文献,搜索用时 15 毫秒
1.
Shumaila Azam Nauman Ahmed Ali Raza Muhammad Sajid Iqbal Muhammad Rafiq Ilyas Khan Kottakkaran Sooppy Nisar Muhammad Ozair Ahmad Zafar Iqbal 《计算机、材料和连续体(英文)》2021,67(3):2933-2948
Recently, the world is facing the terror of the novel corona-virus, termed as COVID-19. Various health institutes and researchers are continuously striving to control this pandemic. In this article, the SEIAR (susceptible, exposed, infected, symptomatically infected, asymptomatically infected and recovered) infection model of COVID-19 with a constant rate of advection is studied for the disease propagation. A simple model of the disease is extended to an advection model by accommodating the advection process and some appropriate parameters in the system. The continuous model is transposed into a discrete numerical model by discretizing the domains, finitely. To analyze the disease dynamics, a structure preserving non-standard finite difference scheme is designed. Two steady states of the continuous system are described i.e., virus free steady state and virus existing steady state. Graphical results show that both the steady states of the numerical design coincide with the fixed points of the continuous SEIAR model. Positivity of the state variables is ensured by applying the M-matrix theory. A result for the positivity property is established. For the proposed numerical design, two different types of the stability are investigated. Nonlinear stability and linear stability for the projected scheme is examined by applying some standard results. Von Neuman stability test is applied to ensure linear stability. The reproductive number is described and its pivotal role in stability analysis is also discussed. Consistency and convergence of the numerical model is also studied. Numerical graphs are presented via computer simulations to prove the worth and efficiency of the quarantine factor is explored graphically, which is helpful in controlling the disease dynamics. In the end, the conclusion of the study is also rendered. 相似文献
2.
Wasfi Shatanawi Ali Raza Muhammad Shoaib Arif Kamaledin Abodayeh Muhammad Rafiq Mairaj Bibi 《计算机、材料和连续体(英文)》2021,66(2):1121-1137
Nonlinear stochastic modeling plays a significant role in disciplines such as psychology, finance, physical sciences, engineering, econometrics, and biological sciences. Dynamical consistency, positivity, and boundedness are fundamental properties of stochastic modeling. A stochastic coronavirus model is studied with techniques of transition probabilities and parametric perturbation. Well-known explicit methods such as Euler Maruyama, stochastic Euler, and stochastic Runge–Kutta are investigated for the stochastic model. Regrettably, the above essential properties are not restored by existing methods. Hence, there is a need to construct essential properties preserving the computational method. The non-standard approach of finite difference is examined to maintain the above basic features of the stochastic model. The comparison of the results of deterministic and stochastic models is also presented. Our proposed efficient computational method well preserves the essential properties of the model. Comparison and convergence analyses of the method are presented. 相似文献
3.
Muhammad Naveed Dumitru Baleanu Muhammad Rafiq Ali Raza Atif Hassan Soori Nauman Ahmed 《计算机、材料和连续体(英文)》2020,65(1):225-241
Mathematical delay modelling has a significant role in the different disciplines
such as behavioural, social, physical, biological engineering, and bio-mathematical
sciences. The present work describes mathematical formulation for the transmission
mechanism of a novel coronavirus (COVID-19). Due to the unavailability of vaccines for
the coronavirus worldwide, delay factors such as social distance, quarantine, travel
restrictions, extended holidays, hospitalization, and isolation have contributed to
controlling the coronavirus epidemic. We have analysed the reproduction number and its
sensitivity to parameters. If, 相似文献
4.
5.
6.
Youngmin Lee 《技术计量学》2020,62(3):313-329
AbstractWe develop a Bayesian nonparametric joint mixture model for clustering spatially correlated time series based on both spatial and temporal similarities. In the temporal perspective, the pattern of a time series is flexibly modeled as a mixture of Gaussian processes, with a Dirichlet process (DP) prior over mixture components. In the spatial perspective, the spatial location is incorporated as a feature for clustering, like a time series being incorporated as a feature. Namely, we model the spatial distribution of each cluster as a DP Gaussian mixture density. For the proposed model, the number of clusters does not need to be specified in advance, but rather is automatically determined during the clustering procedure. Moreover, the spatial distribution of each cluster can be flexibly modeled with multiple modes, without determining the number of modes or specifying spatial neighborhood structures in advance. Variational inference is employed for the efficient posterior computation of the proposed model. We validate the proposed model using simulated and real-data examples. Supplementary materials for the article are available online. 相似文献
7.
8.
9.
10.
一类带接种和年龄结构的流行病模型分析 总被引:4,自引:0,他引:4
讨论了一类具有年龄结构和接种措施的SEIB流行病模型,其中治愈者无终生免疫力。获得了再生数的解析表示,无病平衡态的局部稳定性及在一定条件下的全局稳定性。证明了地方病平衡态的存在性和不存在性。 相似文献
11.
12.
Ning Wang Marion R. Reynolds Jr. 《Quality and Reliability Engineering International》2015,31(6):1023-1034
When monitoring a proportion p, it is usually assumed that the binary observations are independent. This paper investigates the problem of monitoring p when the binary observations follow a two‐state Markov chain model with first‐order dependence. A Markov binary generalized likelihood ratio (MBGLR) chart based on a likelihood ratio statistic with an upper bound on the estimate of p is proposed. The MBGLR chart is used to monitor a continuous stream of autocorrelated binary observation. The MBGLR chart with a relatively large upper bound has good overall performance over a wide range of shifts. The extra number of defectives is defined to measure the loss when using control charts for monitoring p. The MBGLR chart is optimized over a range of upper bounds for the MLE of p. The numerical results show that the optimized MBGLR chart has a smaller extra number of defectives than the optimized Markov binary cumulative sum chart that can detect a shift in p much faster than a Shewhart‐type chart. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
13.
研究了一个具有年龄结构的接种SIS流行病模型渐近性态,得到了正平衡解存在及其局部渐近稳定的充分条件。 相似文献
14.
竞争-竞争-互惠交错扩散模型是一类强耦合的抛物型方程组,关于该模型时变解的整体存在性的研究结果很少,特别是在高维空间中。本文应用能量估计方法,极值原理和抛物型方程的正则性理论证明了:对竞争种群含弱交错扩散项的竞争-竞争-互惠交错扩散模型,它在任意维空间中存在古典的整体解。 相似文献
15.
C. S. Ryoo R. P. Agarwal 《International journal for numerical methods in engineering》2002,54(11):1535-1556
We consider a numerical method that enables us to verify the existence of solutions for variational inequalities. This method is based on the infinite dimensional fixed point theorems and explicit error estimates for finite element approximations. Using the finite element approximations and explicit a priori error estimates, we present an effective verification procedure that through numerical computation generates a set which includes the exact solution. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
16.
Jos R. Fernndez Rebeca Martínez Georgios E. Stavroulakis 《International journal for numerical methods in engineering》2009,77(2):261-284
In this paper, we analyze an algorithm for the quasistatic evolution of the mechanical state of an elasto‐piezoelectric body with damage. Both damage, caused by the development and the growth of internal microcracks, and piezoelectric effects, are included in the model. The mechanical problem is expressed as an elliptic system for the displacement field coupled with a non‐linear parabolic partial differential equation for the damage field and a linear partial differential equation for the electric potential. The variational formulation leads to a coupled system composed of two linear variational equations for the displacement field and the electric potential, and a non‐linear parabolic variational equation for the damage field. The existence of a unique weak solution is stated. Then, a fully discrete scheme is introduced by using the finite element method to approximate the spatial variable and an Euler scheme to discretize the time derivatives. Error estimates are derived on the approximate solutions, from which the linear convergence of the algorithm is deduced under suitable regularity conditions. Finally, some numerical simulations are performed, in one, two and three dimensions, to demonstrate the accuracy of the scheme and the behaviour of the solution. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
17.
引入辅助系统、应用比较原理及Lyapunov函数,讨论具有连续无限时滞三斑块扩散捕食系统解的正性和有界性,给出了正平衡点全局渐近稳定的充分条件。 相似文献
18.
Cheon Seoung Ryoo 《International journal for numerical methods in engineering》2008,73(8):1181-1196
We proposed a numerical method to verify the existence of solutions for a simplified Signorini problem (Comput. Math. Appl. 2000; 40 :1003–1013). Using sequential iteration method, we numerically constructed a set containing solutions that satisfies the hypothesis of Schauder's fixed point theorem in a certain Sobolev space. It is difficult to apply this method to the problem of which associated operator is not retractive in a neighborhood of the solution. In this paper, in order to overcome such a difficulty, we describe an alternative approach to this problem. Numerical examples are presented. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
19.
捕食者有病的生态-流行病SIS模型的分析 总被引:10,自引:0,他引:10
建立并分析了捕食者具有疾病的生态一流行病SIS模型,讨论了解的有界性。应用特征根法得到了平衡点局部渐近稳定的充分条件,进一步,分析了平衡点的全局稳定性,得到了边界平衡点和正平衡点全局稳定的充分条件。 相似文献
20.
针对媒体宣传教育对人们行为方式和生活习惯的影响,本文考虑了由于媒体影响而导致易感性不同的一个SEI传染病模型。分析了模型可能出现的后项分支及其平衡点的稳定性和持久性。结果表明,当基本再生数小于1时,模型的无病平衡点全局稳定;当基本再生数大于1时,地方病平衡点一致持久。同时,利用控制理论,本文也研究了媒体的宣传作用对易感者进行影响和教育的最优控制措施,给出了使目标函数值最小的最优控制,并用数值模拟显示了模型解的动力学性态及控制措施对防止疾病蔓延所起的作用。 相似文献