Inverse Source Problems for the Stochastic Wave Equations: Far-Field Patterns
This paper addresses the direct and inverse source problems for the stochastic acoustic, biharmonic, electromagnetic, and elastic wave equations in a unified framework. The driven source is assumed to be a centered generalized microlocally isotropic ...
Reconstructing Stieltjes Functions from Their Approximate Values: A Search for a Needle in a Haystack
Material response of real, passive, linear, time-invariant media to external influences is described by complex analytic functions of frequency that can always be written in terms of Stieltjes functions---a special class of analytic functions mapping a ...
A Multiscale Poromechanics Model Integrating Myocardial Perfusion and the Epicardial Coronary Vessels
- Nicolás Alejandro Barnafi Wittwer,
- Simone Di Gregorio,
- Luca Dede',
- Paolo Zunino,
- Christian Vergara,
- Alfio Quarteroni
The importance of myocardial perfusion at the outset of cardiac disease remains largely understudied. To address this topic we present a mathematical model that considers the systemic circulation, the coronary vessels, the myocardium, and the interactions ...
Oscillations in a Becker--Döring Model with Injection and Depletion
We study the Becker--Döring bubblelator, a variant of the Becker--Döring coagulation-fragmentation system that models the growth of clusters by gain or loss of monomers. Motivated by models of gas evolution oscillators from physical chemistry, we incorporate ...
Existence, Uniqueness, and Numerical Modeling of Wine Fermentation Based on Integro-Differential Equations
Predictive modeling is key for saving time and resources in manufacturing processes such as fermentation arising in food and chemical manufacturing. To make reliable predictions, realistic models representing the most important process features are ...
Doubly Stochastic Pairwise Interactions for Agreement and Alignment
Random pairwise encounters often occur in large populations or groups of mobile agents, and various types of local interactions that happen at encounters account for emergent global phenomena. In particular, in the fields of swarm robotics, sociobiology, ...
Tilt Grain Boundaries of Hexagonal Structures: A Spectral Viewpoint
We propose a spectral viewpoint for grain boundaries that are generally quasiperiodic. To accurately capture the spectra computationally, it is crucial to adopt the projection method for quasiperiodic functions. Armed with the Lifshitz--Petrich free ...
On the Half-Space Matching Method for Real Wavenumber
The Half-Space Matching (HSM) method has recently been developed as a new method for the solution of two-dimensional scattering problems with complex backgrounds, providing an alternative to Perfectly Matched Layers (PML) or other artificial boundary ...
High Spots for the Ice-Fishing Problem with Surface Tension
In the ice-fishing problem, a half-space of fluid lies below an infinite rigid plate (``the ice'') with a hole. We investigate the ice-fishing problem including the effects of surface tension on the free surface. The dimensionless number that describes the ...
Time and Energy Costs for Synchronization of Kuramoto-Oscillator Networks With or Without Noise Perturbation
In this paper, time and energy costs for achieving synchronization of the Kuramoto-oscillator network with or without noise perturbation are investigated. In order to achieve synchronization and optimize time and energy consumption, a novel switching ...
Near-Exact Radiating Fins via Boundary Tracing
In contexts such as space travel, thermal radiation is the primary mode of heat transfer. The Stefan--Boltzmann law gives rise to a boundary flux which is quartic in temperature, and this nonlinearity renders even the simplest of conduction--radiation ...
Analysis of Obstacles Immersed in Viscous Fluids Using Brinkman's Law for Steady Stokes and Navier--Stokes Equations
From the steady Stokes and Navier--Stokes models, a penalization method has been considered by several authors for approximating those fluid equations around obstacles. In this work, we present a justification for using fictitious domains to study obstacles ...
Acoustics of a Partially Partitioned Narrow Slit Connected to a Half-Plane: Case Study for Exponential Quasi-Bound States in the Continuum and their Resonant Excitation
Localized wave oscillations in an open system that do not decay or grow in time, despite their frequency lying within a continuous spectrum of radiation modes carrying energy to or from infinity, are known as bound states in the continuum (BIC). Small ...
Boundary Tracing for Laplace's Equation with Conformal Mapping
The conformal mapping technique has long been used to obtain exact solutions to Laplace's equation in two-dimensional domains with awkward geometries. However, a major limitation of the technique is that it is only directly compatible with Dirichlet and ...
Soil Searching by an Artificial Root
We model an artificial root which grows in the soil for underground prospecting. Its evolution is described by a controlled system of two integro-partial differential equations: one for the growth of the body and the other for the elongation of the tip. At ...
Spurious Quasi-Resonances in Boundary Integral Equations for the Helmholtz Transmission Problem
We consider the Helmholtz transmission problem with piecewise-constant material coefficients and the standard associated direct boundary integral equations. For certain coefficients and geometries, the norms of the inverses of the boundary integral ...
Slow Migration of Brine Inclusions in First-Year Sea Ice
We derive a thermodynamically consistent model for liquid-solid phase change in sea ice by incorporating a phase sensitive scalar to a classical framework of liquid-solid phase change. The entropy of the scalar is taken relative to the liquid molar ...
Classifying Minimum Energy States for Interacting Particles: Spherical Shells
Particles interacting through long-range attraction and short-range repulsion given by power-laws have been widely used to model physical and biological systems and to predict or explain many of the patterns they display. Apart from rare values of the ...
Wobbling of Pedestrian Bridges
On June 10, 2000, the Millennium Bridge in London opened to the public. As people crossed it, it wobbled, leading to its closure three days later. It reopened after modifications to prevent the wobbling were made. To gain understanding on the physics ...
Efficient and Reliable Overlay Networks for Decentralized Federated Learning
We propose near-optimal overlay networks based on $d$-regular expander graphs to accelerate decentralized federated learning (DFL) and improve its generalization. In DFL a massive number of clients are connected by an overlay network, and they solve machine ...
On the Dynamics of a Diffusive Foot-and-Mouth Disease Model with Nonlocal Infections
Foot-and-mouth disease (FMD) is an acute and highly contagious infectious disease of cloven-hoofed animals. In order to reveal the transmission dynamics and explore effective control measures of FMD, we formulate a diffusive FMD model with a fixed latent ...
On the Validity of the Tight-Binding Method for Describing Systems of Subwavelength Resonators
The goal of this paper is to relate the capacitance matrix formalism to the tight-binding approximation. By doing so, we open the way to the use of mathematical techniques and tools from condensed matter theory in the mathematical and numerical analysis of ...