Stability analysis

稳定性分析
  • 文章类型: Journal Article
    从(21)维旋转黑洞构造薄壳虫洞的动机源于研究该特定时空中非最小耦合标量场的影响的愿望。通过研究这种场在存在旋转的情况下的行为,我们可以深入了解低维系统中重力场和标量场之间的相互作用。此外,这种构造使我们能够探索黑洞物理学与可穿越虫洞等奇异现象之间的潜在联系。考虑围绕平衡喉部半径的径向扰动,以探索物理参数特定值的稳定配置。然后,状态方程,特别是用于外来物质的类幻影和广义Chaplygin气体模型,用于对反向旋转的薄壳虫孔的稳定性进行广泛研究。我们的结果表明,标量场的存在增强了反向旋转的薄壳虫洞的稳定性。
    The motivation for constructing a thin-shell wormhole from a (2+1)-dimensional rotating black hole arises from the desire to study the effects of a nonminimally coupled scalar field in this particular spacetime. By investigating the behavior of such a field in the presence of rotation, we can gain insights into the interplay between gravity and scalar fields in lower-dimensional systems. Additionally, this construction allows us to explore potential connections between black hole physics and exotic phenomena like traversable wormholes. The radial perturbation around the equilibrium throat radius is considered to explore the stable configuration for specific values of physical parameters. Then, the equations of state, specifically the phantom-like and generalized Chaplygin gas model for exotic matter is used to conduct an extensive investigation into the stability of the counter-rotating thin-shell wormholes. Our results show that the presence of a scalar field enhances the stability of the counter-rotating thin-shell wormholes.
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  • 文章类型: Journal Article
    本文论证了,一种数值方法,用于求解涉及具有非奇异核的时间分数Atangana-BaleanuCaputo(ABC)导数的一维和二维Burgers方程。数值策略由时间分数(ABC)导数的正交规则以及一维和二维问题的Haar小波(HW)近似组成。该方案的关键特征是通过搭配过程将分数问题简化为线性方程组。求解该系统给出了给定问题的近似解。为了验证所开发方法的有效性,考虑了五个数值示例。除此之外,将获得的模拟与一些已发表的工作进行比较,并确定提出的技术更好。此外,在计算上给出了时空方向的收敛速度,显示了二阶收敛。还通过Lax-Richtmyer准则描述了所提出方案的稳定性。从仿真中可以明显看出,该方案对于时间分数问题非常有用。
    This paper demonstrates, a numerical method to solve the one and two dimensional Burgers\' equation involving time fractional Atangana-Baleanu Caputo ( ABC ) derivative with a non-singular kernel. The numerical stratagem consists of a quadrature rule for time fractional ( ABC ) derivative along with Haar wavelet (HW) approximations of one and two dimensional problems. The key feature of the scheme is to reduce fractional problems to the set of linear equations via collocation procedure. Solving the system gives the approximate solution of the given problem. To verify the effectiveness of the developed method five numerical examples are considered. Besides this, the obtained simulations are compared with some published work and identified that proposed technique is better. Moreover, computationally the convergence rate in spatiotemporal directions is presented which shows order two convergence. The stability of the proposed scheme is also described via Lax-Richtmyer criterion. From simulations it is obvious that the scheme is quite useful for the time fractional problems.
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  • 文章类型: Journal Article
    人类乳头瘤病毒(HPV)正在威胁人类健康,因为它在全球范围内以不同程度传播。另一方面,信息传递的速度和范围不断提高,以及与HPV相关的新闻报道数量显着增加,探索媒体新闻报道在病毒传播和控制中的作用从未如此重要。利用一个递减的因素来捕捉媒体对人们行为的影响,本文开发了一个模型,描述了HPV传播与媒体影响的动力学,疫苗接种和恢复。我们通过几何方法获得了平衡点的全局稳定性,并通过敏感性分析进一步产生有效的方法来遏制HPV大流行。有了中心流形理论,我们证明了当R0=1时存在正向分岔。我们的研究表明,除了控制感染和易感人群之间的接触并提高有效的疫苗覆盖率,更好的干预措施是加强媒体报道。此外,我们证明,接触率和媒体报道的影响导致多重流行的感染,当某些条件得到满足,这意味着干预措施需要根据具体情况进行调整。
    The human papillomavirus (HPV) is threatening human health as it spreads globally in varying degrees. On the other hand, the speed and scope of information transmission continues to increase, as well as the significant increase in the number of HPV-related news reports, it has never been more important to explore the role of media news coverage in the spread and control of the virus. Using a decreasing factor that captures the impact of media on the actions of people, this paper develops a model that characterizes the dynamics of HPV transmission with media impact, vaccination and recovery. We obtain global stability of equilibrium points employing geometric method, and further yield effective methods to contain the HPV pandemic by sensitivity analysis. With the center manifold theory, we show that there is a forward bifurcation when R0=1. Our study suggested that, besides controlling contact between infected and susceptible populations and improving effective vaccine coverage, a better intervention would be to strengthen media coverage. In addition, we demonstrated that contact rate and the effect of media coverage result in multiple epidemics of infection when certain conditions are met, implying that interventions need to be tailored to specific situations.
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  • 文章类型: Journal Article
    目的:肝炎病毒感染正在影响全球数百万人,导致死亡,残疾,和相当大的支出。丙型肝炎病毒(HCV)的慢性感染可导致严重的公共卫生问题,因为它们的高患病率和不良的长期临床结果。因此,研究了在记忆效应的影响下涉及部分免疫的丙型肝炎病毒的分数阶流行模型,以了解HCV感染的传播方式和患病率。研究HCV的传播动力学使该问题更加有趣。在这项研究中检查了HCV流行模型和全球动态。使用下一代矩阵技术计算HCV模型的基本复制数。我们使用再现数确定模型的全球动态,Lyapunov函数方法,和劳斯-赫维兹标准。模型的繁殖数显示了疾病的进展。
    方法:建立了HCV感染的分数微分方程模型。最大相关参数,比如分数幂,HCV传播率,再现数,等。,影响动态过程,已被合并。使用分数阶Adams方法获得模型的数值解。最后,数值模拟支持理论结论,显示了两者之间的伟大协议。
    结果:在分数阶HCV感染模型中,记忆效应,这在经典模型中是看不到的,在图表上显示,以便可以看到疾病动力学和矢量区室。我们发现分数阶HCV感染模型比常规衍生物具有更多的自由度。分数阶导数,这可能是最好和最可靠的,比经典秩序更好地解释了身体方法。
    结论:本研究建模并分析了分数阶HCV感染模型。目前的方法导致更好地了解HCV在人群中的传播,这导致了对其传播和控制的重要见解,如不同年龄组更好的治疗剂量,确定最佳控制措施,改善健康,延长寿命,降低HCV传播的风险,有效提高HCV患者的生活质量。分数阶HCV感染模型的建立,这提供了对HCV传播动力学的更好理解,并导致对更好的治疗剂量的重要见解,最佳控制措施的识别,并最终改善HCV患者的生活质量,是这项研究的主要结果。
    OBJECTIVE: Hepatitis virus infections are affecting millions of people worldwide, causing death, disability, and considerable expenditure. Chronic infection with hepatitis C virus (HCV) can cause severe public health problems because of their high prevalence and poor long-term clinical outcomes. Thus a fractional-order epidemic model of the hepatitis C virus involving partial immunity under the influence of memory effect to know the transmission patterns and prevalence of HCV infection is studied. Investigating the transmission dynamics of HCV makes the issue more interesting. The HCV epidemic model and worldwide dynamics are examined in this study. Calculate the basic reproduction number for the HCV model using the next-generation matrix technique. We determine the model\'s global dynamics using reproduction numbers, the Lyapunov functional approach, and the Routh-Hurwitz criterion. The model\'s reproduction number shows how the disease progresses.
    METHODS: A fractional differential equation model of HCV infection has been created. Maximum relevant parameters, such as fractional power, HCV transmission rate, reproduction number, etc., influencing the dynamic process, have been incorporated. The model\'s numerical solutions are obtained using the fractional Adams method. Finally, numerical simulations support the theoretical conclusions, showing the great agreement between the two.
    RESULTS: In the fractional-order HCV infection model, the memory effect, which is not seen in the classical model, was shown on graphs so that disease dynamics and vector compartments could be seen. We found that the fractional-order HCV infection model has more stages of freedom than regular derivatives. Fractional-order derivations, which may be the best and most reliable, explained bodily approaches better than classical order.
    CONCLUSIONS: The current study modeled and analyzed a fractional-order HCV infection model. The current approach results in a much better understanding of HCV transmission in a population, which leads to important insights into its spread and control, such as better treatment dosage for different age groups, identifying the best control measure, improving health, prolonging life, reducing the risk of HCV transmission, and effectively increasing the quality of life of HCV patients. The creation of a fractional-order HCV infection model, which provides a better understanding of HCV transmission dynamics and leads to significant insights for better treatment dosages, identification of optimal control measures, and ultimately improvement of the quality of life for HCV patients, is the study\'s major outcome.
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  • 文章类型: Journal Article
    目的通过酶法制备具有钙结合能力的鲭鱼肽(MPs),并探讨其在体外提高钙生物利用度的潜在作用。钙结合能力,水解度(DH),分子量(MW),并测定了MPs的电荷分布随酶解时间的变化。使用光谱学和形态分析对鲭鱼肽-钙(MP-钙)复合物进行了结构表征。结果表明,当使用alcalase3h时,所得MPs的最大钙结合能力为120.95mg/g,DH为15.45%。此外,随着水解时间的增加,国会议员的MW减少了,负电荷增加。MPs的天冬氨酸(Asp)和谷氨酸(Glu)中的羧基和氨基可以充当钙结合位点,它们通过分子间相互作用与钙离子进一步组装成紧凑的纳米级球形复合物。此外,即使在草酸的影响下,MP-钙复合物保持一定的溶解度。本研究为开发新型钙补充剂和有效利用鲭鱼蛋白质资源提供了依据。
    The purpose of this study was to prepare mackerel peptides (MPs) with calcium-binding capacity through an enzyme method and to investigate the potential role they play in improving the bioavailability of calcium in vitro. The calcium-binding capacity, degree of hydrolysis (DH), molecular weight (MW), and charge distribution changes with the enzymolysis time of MPs were measured. The structural characterization of mackerel peptide-calcium (MP-calcium) complexes was performed using spectroscopy and morphology analysis. The results showed that the maximum calcium-binding capacity of the obtained MPs was 120.95 mg/g when alcalase was used for 3 h, with a DH of 15.45%. Moreover, with an increase in hydrolysis time, the MW of the MPs decreased, and the negative charge increased. The carboxyl and amino groups in aspartic (Asp) and glutamate (Glu) of the MPs may act as calcium-binding sites, which are further assembled into compact nanoscale spherical complexes with calcium ions through intermolecular interactions. Furthermore, even under the influence of oxalic acid, MP-calcium complexes maintained a certain solubility. This study provides a basis for developing new calcium supplements and efficiently utilizing the mackerel protein resource.
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  • 文章类型: Journal Article
    围岩地压特性通常被认为是采场结构和工艺参数优化的理论基础。为探索山津金矿第二步下行回填采场高效方法的可行性,采用各种数值模拟方法,研究了板墙回填结构对下采系统围岩稳定性的影响。最大主应力,人工假屋顶应力,和位移进行了分析,以评估不同矿区的地压水平。这些结果表明了回填采场的优化结构参数,这也可以提供一种低成本的方式来实现向下路线采矿系统的高安全性。
    Characteristic of ground pressure in surrounding rock is generally considered as the theoretical basis of parameter optimization for stope structure and technology. To explore the feasibility of efficient method for the second-step downward route backfill stopes in Shanjin gold mine, various numerical simulation methods were used to investigate the effect of slab-wall backfill structure on stability of surrounding rock in downward route mining system. The maximum principal stress, artificial false roof stress, and displacement were analyzed to evaluate the level of ground pressure in different mining areas. These results indicate the optimized structural parameters for backfill stopes, which may also provide a low-cost way to achieve a high safety for downward route mining system.
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  • 文章类型: Journal Article
    本研究旨在探索非线性BenjaminBonaMahonyBurgers(BBMB)方程的精确解析,应用于各种非线性科学学科,包括流体动力学,冲击产生,波传输,和孤子理论。在这篇论文中,我们采用两种通用的方法,特别是扩展的exp(-kW(χ))展开技术和新颖的Kudryashov方法,辨识非线性BBMB方程的精确孤子解。我们发现的解决方案涉及三角函数,双曲函数,和合理的功能。这项研究的独特性在于发现明亮的孤子,扭结波解决方案,和周期波解,进行稳定性分析。此外,通过利用数学软件Maple2022(https://maplesoft.com/downloads/selectplatform)探索了解决方案的图形特征。aspx?hash=61ab59890f2313b2241fde3423fd975e)。系统的物理解释是通过各种类型的图形定义的,包括等高线图,3D曲面图,和线图,使用适当的参数值。这些推荐的技术具有重要意义,适用于非线性科学领域中用于说明非线性物理模型的各种非线性演化方程。
    This study aims to explore the precise resolution of the nonlinear Benjamin Bona Mahony Burgers (BBMB) equation, which finds application in a variety of nonlinear scientific disciplines including fluid dynamics, shock generation, wave transmission, and soliton theory. Within this paper, we employ two versatile methodologies, specifically the extended exp ( - Ψ ( χ ) ) expansion technique and the novel Kudryashov method, to identify the exact soliton solutions of the nonlinear BBMB equation. The solutions we discovered involve trigonometric functions, hyperbolic functions, and rational functions. The uniqueness of this research lies in uncovering the bright soliton, kink wave solution, and periodic wave solution, and conducting stability analysis. Furthermore, the solutions\' graphical characteristics were explored through the utilization of the mathematical software Maple 2022 ( https://maplesoft.com/downloads/selectplatform.aspx?hash=61ab59890f2313b2241fde3423fd975e ). The system\'s physical interpretation is defined through various types of graphs, including contour graphs, 3D-surface graphs, and line graphs, which use appropriate parameter values. These recommended techniques hold significant importance and are applicable in diverse nonlinear evolutionary equations found in the field of nonlinear sciences for illustrating nonlinear physical models.
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  • 文章类型: Journal Article
    这项研究对代表COVID-19的非线性数学模型进行了详细分析,纳入了环境因素和社会距离措施。它彻底分析了模型的平衡点,计算基本繁殖率,并评估模型在无病和地方病平衡状态下的稳定性,本地和全球。此外,进行了敏感性分析。这项研究发展了复杂的稳定性理论,主要关注Volterra-Lyapunov(V-L)矩阵方法的特点。要了解COVID-19的动态行为,数值模拟是必不可少的。为此,这项研究采用了一种稳健的数值技术,称为非标准有限差分(NSFD)方法,由Mickens介绍。通过不同参数值的图形表示直观地呈现各种结果,以说明环境因素和社会距离措施的影响。
    This research conducts a detailed analysis of a nonlinear mathematical model representing COVID-19, incorporating both environmental factors and social distancing measures. It thoroughly analyzes the model\'s equilibrium points, computes the basic reproductive rate, and evaluates the stability of the model at disease-free and endemic equilibrium states, both locally and globally. Additionally, sensitivity analysis is carried out. The study develops a sophisticated stability theory, primarily focusing on the characteristics of the Volterra-Lyapunov (V-L) matrices method. To understand the dynamic behavior of COVID-19, numerical simulations are essential. For this purpose, the study employs a robust numerical technique known as the non-standard finite difference (NSFD) method, introduced by Mickens. Various results are visually presented through graphical representations across different parameter values to illustrate the impact of environmental factors and social distancing measures.
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  • 文章类型: Journal Article
    近年来,由于分数阶微积分能够对具有不确定性和记忆效应的复杂现象进行建模,因此将其纳入随机延迟系统的兴趣越来越大。分数随机延迟微分方程在对各种应用领域的复杂动力学系统进行建模时是常规的。本研究提出了一种新颖的频谱方法,以证明以随机性以及分数导数和时间延迟为特征的系统的稳定性行为和数值解。通过弥合分数微积分之间的差距,随机过程,和光谱分析,这项工作有助于分数动力学领域,并丰富了可用于研究具有延迟和不确定性的系统的稳定性的分析工具的工具箱。为了说明我们方法的实际意义并验证我们方法的理论发现,给出了一些数值模拟。
    In recent years, there has been a growing interest in incorporating fractional calculus into stochastic delay systems due to its ability to model complex phenomena with uncertainties and memory effects. The fractional stochastic delay differential equations are conventional in modeling such complex dynamical systems around various applied fields. The present study addresses a novel spectral approach to demonstrate the stability behavior and numerical solution of the systems characterized by stochasticity along with fractional derivatives and time delay. By bridging the gap between fractional calculus, stochastic processes, and spectral analysis, this work contributes to the field of fractional dynamics and enriches the toolbox of analytical tools available for investigating the stability of systems with delays and uncertainties. To illustrate the practical implications and validate the theoretical findings of our approach, some numerical simulations are presented.
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  • 文章类型: Journal Article
    传染病在人类历史上一直是一股塑造力量,需要全面了解它们的动态。本研究引入了一个整合流行病学和进化动力学的共同进化模型。利用微分方程组,该模型代表了易感人群之间的相互作用,感染,并恢复了祖先和进化病毒株的种群。方法严谨,验证了模型的存在性和唯一性,它既适用于确定性的情况,也适用于随机的情况。已经采用了无数的图形技术来阐明模型的动力学。除了其理论贡献,该模型是公共卫生战略的重要工具,特别是在病毒突变危及现有干预措施的情况下预测未来的疫情。
    Infectious diseases have long been a shaping force in human history, necessitating a comprehensive understanding of their dynamics. This study introduces a co-evolution model that integrates both epidemiological and evolutionary dynamics. Utilizing a system of differential equations, the model represents the interactions among susceptible, infected, and recovered populations for both ancestral and evolved viral strains. Methodologically rigorous, the model\'s existence and uniqueness have been verified, and it accommodates both deterministic and stochastic cases. A myriad of graphical techniques have been employed to elucidate the model\'s dynamics. Beyond its theoretical contributions, this model serves as a critical instrument for public health strategy, particularly predicting future outbreaks in scenarios where viral mutations compromise existing interventions.
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