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A Hierarchy of Kinetic Discrete-Velocity Models for Traffic Flow Derived from a Nonlocal Prigogine–Herman Model 从非局部普里戈金-赫尔曼模型推导出的交通流离散速度动力学模型层次结构
IF 1.9 4区 数学 Q2 Mathematics Pub Date : 2024-01-30 DOI: 10.1137/23m1583065
R. Borsche, A. Klar
SIAM Journal on Applied Mathematics, Volume 84, Issue 1, Page 139-164, February 2024.
Abstract. Starting from a nonlocal version of the Prigogine–Herman traffic model, we derive a natural hierarchy of kinetic discrete-velocity models for traffic flow consisting of systems of quasi-linear hyperbolic equations with relaxation terms. The hyperbolic main part of these models turns out to have several favorable features. In particular, we determine Riemann invariants and prove richness and total linear degeneracy of the hyperbolic systems. Moreover, a physically reasonable invariant domain is obtained for all equations of the hierarchy. Additionally, we investigate the full relaxation system with respect to stability and persistence of periodic (stop-and-go-type) solutions and derive a condition for the appearance of such solutions. Finally, numerical results for various situations are presented, illustrating the analytical findings.
SIAM 应用数学杂志》第 84 卷第 1 期第 139-164 页,2024 年 2 月。 摘要从普里戈金-赫尔曼交通模型的非局部版本出发,我们推导出了由带松弛项的准线性双曲方程系统组成的交通流离散速度动力学模型的自然层次。事实证明,这些模型的双曲主体部分具有若干有利特征。特别是,我们确定了黎曼不变式,并证明了双曲系统的丰富性和总线性退化性。此外,我们还为层次结构的所有方程获得了物理上合理的不变域。此外,我们还研究了全松弛系统的稳定性和周期性(走走停停型)解的持久性,并推导出了此类解出现的条件。最后,我们给出了各种情况下的数值结果,以说明分析结果。
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引用次数: 0
A Domain Decomposition Method for Solution of a PDE-Constrained Generalized Nash Equilibrium Model of Biofilm Community Metabolism 用领域分解法求解生物膜群落代谢的 PDE 受限广义纳什均衡模型
IF 1.9 4区 数学 Q2 Mathematics Pub Date : 2024-01-24 DOI: 10.1137/22m1511023
Isaac Klapper, Daniel B. Szyld, Xinli Yu, Karsten Zengler, Tianyu Zhang, Cristal Zúñiga
SIAM Journal on Applied Mathematics, Volume 84, Issue 1, Page 97-113, February 2024.
Abstract. Microbes are able to deploy different strategies in response to, and depending upon, local environmental conditions. In the setting of a microbial community, this property induces a Nash equilibrium problem because access to environmental resources is bounded. If microbes are also distributed in space, then those resources are subject to transport limitations (encoded in a PDE) and so microbial strategies at one location influence resources and, hence, microbial strategies, at another. Here we formulate the resulting PDE-coupled generalized Nash equilibrium problem for a multispecies biofilm community, and propose a domain-decomposition-based method for its solution. An example consisting of a model with two microbial species biofilm with 33 externally transported chemical concentrations is presented.
SIAM 应用数学杂志》第 84 卷第 1 期第 97-113 页,2024 年 2 月。 摘要微生物能够根据当地的环境条件部署不同的策略。在微生物群落的环境中,由于环境资源的获取是有限制的,因此这一特性导致了纳什均衡问题。如果微生物也分布在空间中,那么这些资源就会受到运输限制(用 PDE 编码),因此一个地点的微生物策略会影响另一个地点的资源,进而影响微生物策略。在这里,我们为一个多物种生物膜群落提出了由此产生的 PDE 耦合广义纳什均衡问题,并提出了一种基于领域分解的求解方法。我们将以两个微生物物种的生物膜模型为例,介绍 33 种外部传输的化学浓度。
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引用次数: 0
Layer Stripping Approach to Reconstruct Shape Variations in Waveguides Using Locally Resonant Frequencies 利用局部谐振频率重构波导形状变化的层剥方法
IF 1.9 4区 数学 Q2 Mathematics Pub Date : 2024-01-22 DOI: 10.1137/23m1546336
Angéle Niclas, Laurent Seppecher
SIAM Journal on Applied Mathematics, Volume 84, Issue 1, Page 75-96, February 2024.
Abstract. This article presents a new method to reconstruct slowly varying width defects in two-dimensional waveguides using one-side section measurements at locally resonant frequencies. At these frequencies, locally resonant modes propagate in the waveguide up to a “cut-off” position. In this particular point, the local width of the waveguide can be recovered. Given multifrequency data measured on a section of the waveguide, we perform an efficient layer stripping approach to recover, section by section, the shape variations. It provides an L infinity-stable method to reconstruct the width of a slowly monotonous varying waveguide. We validate this method on numerical data and discuss its limits.
SIAM 应用数学杂志》第 84 卷第 1 期第 75-96 页,2024 年 2 月。 摘要本文介绍了一种在局部谐振频率下利用单侧截面测量重建二维波导中缓慢变化的宽度缺陷的新方法。在这些频率下,局部谐振模式在波导中传播到一个 "截止 "位置。在这个特定位置,可以恢复波导的局部宽度。根据在一段波导上测量到的多频数据,我们采用一种高效的层剥离方法,逐段恢复波导的形状变化。它提供了一种 L 无限稳定的方法来重建缓慢单调变化的波导宽度。我们在数值数据上验证了这种方法,并讨论了它的局限性。
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引用次数: 0
Nonlinear Monotone Energy Stability of Plane Shear Flows: Joseph or Orr Critical Thresholds? 平面剪切流的非线性单调能量稳定性:约瑟夫临界阈值还是奥尔临界阈值?
IF 1.9 4区 数学 Q2 Mathematics Pub Date : 2024-01-18 DOI: 10.1137/22m1535826
Giuseppe Mulone
SIAM Journal on Applied Mathematics, Volume 84, Issue 1, Page 60-74, February 2024.
Abstract. Critical Reynolds numbers for the monotone exponential energy stability of Couette and Poiseuille plane flows were obtained by Orr in 1907 [Proc. Roy. Irish Acad. A, 27 (1907), pp. 9–68, 69–138] in a famous paper, and by Joseph in 1966 [J. Fluid Mech., 33 (1966), pp. 617–621], Joseph and Carmi in 1969 [Quart. Appl. Math., 26 (1969), pp. 575–579], and Busse in 1972 [Arch. Ration. Mech. Anal., 47 (1972), pp. 28–35]. All these authors obtained their results applying variational methods to compute the maximum of a functional ratio derived from the Reynolds–Orr energy identity. Orr and Joseph obtained different results; for instance, in the Couette case Orr computed the critical Reynolds value of 44.3 (on spanwise perturbations) and Joseph 20.65 (on streamwise perturbations). Recently in [P. Falsaperla, G. Mulone, and C. Perrone, Eur. J. Mech. B Fluids, 93 (2022), pp. 93–100], the authors conjectured that the search of the maximum should be restricted to a subspace of the space of kinematically admissible perturbations. With this conjecture, the critical nonlinear energy Reynolds number was found among spanwise perturbations (a Squire theorem for nonlinear systems). With a direct proof and an appropriate and original decomposition of the dissipation terms in the Reynolds–Orr identity we show the validity of this conjecture in the space of three-dimensional perturbations.
SIAM 应用数学杂志》第 84 卷第 1 期第 60-74 页,2024 年 2 月。 摘要。奥尔在 1907 年的一篇著名论文[Proc. Roy. Irish Acad. A, 27 (1907), pp、33 (1966),第 617-621 页],Joseph 和 Carmi 于 1969 年[Quart. Appl. Math.,26 (1969),第 575-579 页],Busse 于 1972 年[Arch. Ration. Mech. Anal.,47 (1972),第 28-35 页]。所有这些作者都是应用变分法计算从雷诺-奥尔能量特性导出的函数比值的最大值而得出的结果。Orr 和 Joseph 获得了不同的结果;例如,在 Couette 情况下,Orr 计算出的临界雷诺值为 44.3(跨向扰动),Joseph 为 20.65(流向扰动)。最近在 [P.Falsaperla, G. Mulone, and C. Perrone, Eur.J. Mech.B Fluids, 93 (2022), pp.根据这一猜想,在跨度扰动中找到了临界非线性能量雷诺数(非线性系统的斯奎尔定理)。通过直接证明和对雷诺-奥尔特性中的耗散项进行适当而新颖的分解,我们证明了这一猜想在三维扰动空间中的有效性。
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引用次数: 0
Multiplicity of Neutrally Stable Periodic Orbits with Coexistence in the Chemostat Subject to Periodic Removal Rate 恒温器中并存的中性稳定周期轨道的多重性(受周期性移除率的影响
IF 1.9 4区 数学 Q2 Mathematics Pub Date : 2024-01-16 DOI: 10.1137/23m1552450
Thomas Guilmeau, Alain Rapaport
SIAM Journal on Applied Mathematics, Volume 84, Issue 1, Page 39-59, February 2024.
Abstract. We identify a taxonomic property on the growth functions in the multispecies chemostat model which ensures the coexistence of a subset of species under periodic removal rate. We show that proportions of some powers of the species densities are periodic functions, leading to an infinity of distinct neutrally stable periodic orbits depending on the initial condition. This condition on the species for neutral stability possesses the feature to be independent of the shape of the periodic signal for a given mean value. We also give conditions allowing the coexistence of two distinct subsets of species. Although these conditions are nongeneric, we show in simulations that when these conditions are only approximately satisfied, the behavior of the solutions is close to that of the nongeneric case over a long time interval, justifying the interest of our study.
SIAM 应用数学杂志》第 84 卷第 1 期第 39-59 页,2024 年 2 月。 摘要我们确定了多物种恒温模型中生长函数的分类学性质,该性质确保了在周期性去除率下物种子集的共存。我们证明,物种密度的某些幂的比例是周期函数,导致无穷多个不同的中性稳定周期轨道,这取决于初始条件。这种中性稳定的物种条件具有与给定平均值的周期信号形状无关的特点。我们还给出了允许两个不同物种子集共存的条件。虽然这些条件是非通用的,但我们通过模拟证明,当这些条件仅近似满足时,在很长的时间间隔内,解的行为接近于非通用情况,这证明了我们的研究是有意义的。
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引用次数: 0
One-Dimensional Short-Range Nearest-Neighbor Interaction and Its Nonlinear Diffusion Limit 一维短程近邻相互作用及其非线性扩散极限
IF 1.9 4区 数学 Q2 Mathematics Pub Date : 2024-01-12 DOI: 10.1137/23m155520x
Michael Fischer, Laura Kanzler, Christian Schmeiser
SIAM Journal on Applied Mathematics, Volume 84, Issue 1, Page 1-18, February 2024.
Abstract. Repulsion between individuals within a finite radius is encountered in numerous applications, including cell exclusion, i.e., avoidance of overlapping cells, bird flocks, or microscopic pedestrian models. We define such individual-based particle dynamics in one spatial dimension with minimal assumptions of the repulsion force [math] as well as their external velocity [math] and prove their characteristic properties. Moreover, we are able to perform a rigorous limit from the microscopic to the macroscopic scale, where we could recover the finite interaction radius as a density threshold. Specific choices for the repulsion force [math] lead to well-known nonlinear diffusion equations on the macroscopic scale, as, e.g., the porous medium equation. At both scaling levels, numerical simulations are presented and compared to underline the analytical results.
SIAM 应用数学杂志》第 84 卷第 1 期第 1-18 页,2024 年 2 月。 摘要有限半径内个体间的排斥在许多应用中都会遇到,包括细胞排斥(即避免重叠细胞)、鸟群或微观行人模型。我们以最小的斥力假设[数学]及其外部速度假设[数学],在一个空间维度上定义了这种基于个体的粒子动力学,并证明了它们的特征特性。此外,我们还能从微观尺度对宏观尺度进行严格的限制,从而恢复作为密度阈值的有限相互作用半径。斥力的特定选择[math]导致了宏观尺度上著名的非线性扩散方程,如多孔介质方程。在这两个尺度上,我们都进行了数值模拟和比较,以强调分析结果。
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引用次数: 0
Combined Field-Only Boundary Integral Equations for PEC Electromagnetic Scattering Problem in Spherical Geometries 球形几何中 PEC 电磁散射问题的组合纯场边界积分方程
IF 1.9 4区 数学 Q2 Mathematics Pub Date : 2024-01-12 DOI: 10.1137/23m1561865
Luiz Maltez-Faria, Carlos Pérez-Arancibia, Catalin Turc
SIAM Journal on Applied Mathematics, Volume 84, Issue 1, Page 19-38, February 2024.
Abstract. We analyze the well-posedness of certain field-only boundary integral equations (BIEs) for frequency domain electromagnetic scattering from perfectly conducting spheres. Starting from the observations that (1) the three components of the scattered electric field [math] and (2) scalar quantity [math] are radiative solutions of the Helmholtz equation, we see that novel boundary integral equation formulations of electromagnetic scattering from perfectly conducting obstacles can be derived using Green’s identities applied to the aforementioned quantities and the boundary conditions on the surface of the scatterer. The unknowns of these formulations are the normal derivatives of the three components of the scattered electric field and the normal component of the scattered electric field on the surface of the scatterer, and thus these formulations are referred to as field-only BIEs. In this paper we use the combined field methodology of Burton and Miller within the field-only BIE approach, and we derive new boundary integral formulations that feature only Helmholtz boundary integral operators, which we subsequently show to be well posed for all positive frequencies in the case of spherical scatterers. Relying on the spectral properties of Helmholtz boundary integral operators in spherical geometries, we show that the combined field-only boundary integral operators are diagonalizable in the case of spherical geometries and their eigenvalues are nonzero for all frequencies. Furthermore, we show that for spherical geometries one of the field-only integral formulations considered in this paper exhibits eigenvalues clustering at one—a property similar to second-kind integral equations.
SIAM 应用数学杂志》第 84 卷第 1 期第 19-38 页,2024 年 2 月。 摘要。我们分析了完全导电球的频域电磁散射的某些纯场边界积分方程(BIE)的好求性。从(1)散射电场的三个分量[math]和(2)标量[math]是亥姆霍兹方程的辐射解这两个观察结果出发,我们发现,利用应用于上述量的格林等式和散射体表面的边界条件,可以推导出完全导电障碍物电磁散射的新边界积分方程公式。这些公式的未知量是散射电场三个分量的法向导数和散射体表面上散射电场的法向分量,因此这些公式被称为纯场边界积分方程。在本文中,我们在纯场 BIE 方法中使用了 Burton 和 Miller 的组合场方法,并推导出了新的边界积分公式,其特点是只有 Helmholtz 边界积分算子。根据亥姆霍兹边界积分算子在球形几何中的频谱特性,我们证明在球形几何情况下,组合的纯场边界积分算子是可对角的,并且其特征值在所有频率下都不为零。此外,我们还证明,对于球面几何,本文所考虑的其中一种纯场积分公式的特征值聚集在1处--这一性质类似于第二类积分方程。
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引用次数: 0
Analysis on a Spatial SIS Epidemic Model with Saturated Incidence Function in Advective Environments: I. Conserved Total Population 具有饱和发病函数的平流环境空间 SIS 流行病模型分析:I. 保持不变的总人口
IF 1.9 4区 数学 Q2 Mathematics Pub Date : 2023-12-08 DOI: 10.1137/22m1534699
Xiaodan Chen, Renhao Cui
SIAM Journal on Applied Mathematics, Volume 83, Issue 6, Page 2522-2544, December 2023.
Abstract. This paper concerns the qualitative analysis on a reaction-diffusion SIS (susceptible-infected-susceptible) epidemic model governed by the saturated incidence infection mechanism in advective environments. A variational expression of the basic reproduction number [math] was derived and the global dynamics of the system in terms of [math] was established: the disease-free equilibrium is unique and linearly stable if [math] and at least an endemic equilibrium exists if [math]. More precisely, we explore qualitative properties of the basic reproduction number and investigate the spatial distribution of the individuals with respect to the dispersal and advection. We find that the concentration phenomenon occurs when the advection is large and the infectious disease will be eradicated for the small dispersal of infected individual. Our theoretical results may shed some new insight into the infectious disease prediction and control strategy.
SIAM 应用数学杂志》,第 83 卷第 6 期,第 2522-2544 页,2023 年 12 月。 摘要本文对平流环境下受饱和感染机制控制的反应-扩散 SIS(易感-感染-易感)流行病模型进行定性分析。推导出了基本繁殖数[math]的变分表达式,并用[math]建立了系统的全局动力学:如果[math],则无病平衡是唯一和线性稳定的;如果[math],则至少存在一个流行平衡。更确切地说,我们探讨了基本繁殖数的定性特性,并研究了个体在扩散和平流方面的空间分布。我们发现,当平流较大时,会出现集中现象,而对于感染个体的小规模扩散,传染病将被根除。我们的理论结果可以为传染病预测和控制策略提供一些新的启示。
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引用次数: 0
Modeling Acoustic Space-Coiled Metacrystals 声学空间卷曲元晶体建模
IF 1.9 4区 数学 Q2 Mathematics Pub Date : 2023-12-06 DOI: 10.1137/22m1527131
Joar Zhou Hagström, Kim Pham, Agnés Maurel
SIAM Journal on Applied Mathematics, Volume 83, Issue 6, Page 2499-2521, December 2023.
Abstract. We present an effective model of “space-coiled metacrystals” composed of a periodic array of sound rigid blocks into which long slots have been coiled up. The periodic cell of the block contains a coiled slot whose straight parts are at wavelength scale, which enables the appearance of Bragg resonances. These resonances, which prevent high transmission, compete with the Fabry–Pérot resonances of the entire slot, which foster perfect transmission. This results in complex scattering properties driven by the characteristics of the turning regions that act as atoms in a one-dimensional coiled crystal. Using appropriate scaling and combining two-scale homogenization with matched asymptotic techniques, the modeling of such metacrystals is proposed. The resulting model is validated through a comparison with full-wave numerics in both harmonic and transient regimes.
SIAM 应用数学杂志》,第 83 卷第 6 期,第 2499-2521 页,2023 年 12 月。 摘要。我们提出了一种有效的 "空间卷曲元晶体 "模型,它由一个周期性的声刚性块阵列组成,其中的长槽被卷曲起来。块的周期性单元包含一个卷曲槽,其直线部分与波长尺度一致,这使得布拉格共振得以出现。这些共振会阻碍高传输,与整个槽的法布里-佩罗共振竞争,从而促进完美传输。这就导致了复杂的散射特性,而散射特性是由转折区域的特性驱动的,这些转折区域就像一维盘绕晶体中的原子。利用适当的缩放并结合二尺度均质化和匹配渐近技术,提出了这种元晶体的建模方法。通过与谐波和瞬态下的全波数值进行比较,验证了由此产生的模型。
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引用次数: 0
Neuronal Resilience and Calcium Signaling Pathways in the Context of Synapse Loss and Calcium Leaks: A Computational MODELING Study and Implications for Alzheimer’s Disease 突触丢失和钙泄漏背景下的神经元弹性和钙信号通路:阿尔茨海默病的计算模型研究和意义
IF 1.9 4区 数学 Q2 Mathematics Pub Date : 2023-12-05 DOI: 10.1137/23m1557842
Piyush R. Borole, James M. Rosado, MeiRose Neal, Gillian Queisser
SIAM Journal on Applied Mathematics, Volume 83, Issue 6, Page 2418-2442, December 2023.
Abstract. In this paper, a coupled electro-calcium model was developed and implemented to computationally explore the effects of neuronal synapse loss, in particular in the context of Alzheimer’s disease. Established parameters affected by Alzheimer’s disease, such as synapse loss, calcium leaks at deteriorating synaptic contacts, and downregulation of the calcium buffer calbindin, are subject to this study. Reconstructed neurons are used to define the computational domain for a system of PDEs and ODEs, discretized by finite differences and solved with a semi-implicit second-order time integrator. The results show neuronal resilience during synapse loss. When incorporating calcium leaks at affected synapses, neurons lose their ability to produce synapse-to-nucleus calcium signals, necessary for learning, plasticity, and neuronal survival. Downregulation of calbindin concentrations partially recovers the signaling pathway to the cell nucleus. These results could define future research pathways toward stabilizing the calcium signaling pathways during Alzheimer’s disease. The coupled electro-calcium model was implemented and solved using MATLAB https://github.com/NeuroBox3D/CalcSim.
SIAM应用数学学报,83卷,第6期,2418-2442页,2023年12月。摘要。本文开发并实现了一个耦合电钙模型,以计算探索神经元突触丢失的影响,特别是在阿尔茨海默病的背景下。受阿尔茨海默病影响的既定参数,如突触丢失、突触接触恶化时的钙泄漏以及钙缓冲物钙结合蛋白的下调,都是本研究的主题。重构神经元用于定义由偏微分方程和偏微分方程组成的系统的计算域,用有限差分离散,用半隐式二阶时间积分器求解。结果显示突触丢失时神经元的恢复能力。当受影响的突触发生钙泄漏时,神经元失去了产生突触到核钙信号的能力,这是学习、可塑性和神经元存活所必需的。下调钙结合蛋白浓度可部分恢复通往细胞核的信号通路。这些结果可以确定未来的研究途径,以稳定阿尔茨海默病期间的钙信号通路。利用MATLAB https://github.com/NeuroBox3D/CalcSim实现并求解了耦合电-钙模型。
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引用次数: 0
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SIAM Journal on Applied Mathematics
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