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Analysis and synthesis of safety-critical autonomous systems are carried out using models which are often dynamic. Two central features of these dynamic systems are parameters and unmodeled dynamics. This paper addresses the use of a…

Systems and Control · Electrical Eng. & Systems 2022-03-17 Arnab Sarker , Peter Fisher , Joseph E. Gaudio , Anuradha M. Annaswamy

We consider an inverse problem for an inhomogeneous wave equation with discrete-in-time sources, modeling a seismic rupture. We assume that the sources occur along a path with subsonic velocity, and that data are collected over time on some…

Analysis of PDEs · Mathematics 2015-11-05 Maarten V. de Hoop , Lauri Oksanen , Justin Tittelfitz

Seismic travel time tomography is a geophysical imaging method to infer the 3-D interior structure of the solid Earth. Most commonly formulated as a linear(ized) inverse problem, it maps differences between observed and expected wave travel…

Numerical Analysis · Mathematics 2024-10-15 Naomi Schneider , Volker Michel , Karin Sigloch , Eoghan J. Totten

In Part I of this study, we obtained the ray (group) velocity gradients and Hessians with respect to the ray locations, directions and the anisotropic model parameters, at nodal points along ray trajectories, considering general anisotropic…

Geophysics · Physics 2021-12-01 Igor Ravve , Zvi Koren

This work investigates a three-dimensional slow-fast stochastic system with quadratic nonlinearity and additive noise, inspired by fluid dynamics. The deterministic counterpart exhibits a periodic orbit and a slow manifold. We demonstrate…

Dynamical Systems · Mathematics 2025-01-22 Mickaël D. Chekroun , Jeroen S. W. Lamb , Christian J. Pangerl , Martin Rasmussen

We consider the problem of inferring the mobility map, which is the distribution of the building occupants at each timestamp, from the temperatures of the rooms. We also want to explore the effects of noise in the temperature measurement,…

Machine Learning · Computer Science 2020-11-17 Risul Islam , Andrey Lokhov , Nathan Lemons , Michalis Faloutsos

This work aims to describe a mathematical model and a numerical method to simulate a thin anisotropic composite membrane moving and deforming in 3D space under a dynamic load of an arbitrary time and space profile. The model and the method…

Numerical Analysis · Mathematics 2020-07-24 Vitalii Aksenov , Alexey Vasyukov , Igor Petrov

This work develops a unified framework for inferring, representing, and statistically characterizing an anisotropic strength surface directly from molecular dynamics data. Large-scale tensile loading simulations are used to generate failure…

Materials Science · Physics 2026-02-19 Alexander Bonacci , John Dolbow , Johann Guilleminot

We consider inverse problems estimating distributed parameters from indirect noisy observations through discretization of continuum models described by partial differential or integral equations. It is well understood that the errors…

Numerical Analysis · Mathematics 2023-10-09 Albero Bocchinfuso , Daniela Calvetti , Erkki Somersalo

Influence of weak uniaxial small-scale anisotropy on the stability of inertial-range scaling regimes in a model of a passive transverse vector field advected by an incompressible turbulent flow is investigated by means of the field…

Chaotic Dynamics · Physics 2007-05-23 E. Jurcisinova , M. Jurcisin , R. Remecky , M. Scholtz

Two new methods are presented for estimating car-following model parameters using data collected from the Adaptive Cruise Control (ACC) enabled vehicles. The vehicle is assumed to follow a constant time headway relative velocity model in…

Applications · Statistics 2022-12-16 Yanbing Wang , George Gunter , Matthew Nice , Daniel B. Work

Compressed sensing is the art of reconstructing a sparse vector from its inner products with respect to a small set of randomly chosen measurement vectors. It is usually assumed that the ensemble of measurement vectors is in isotropic…

Information Theory · Computer Science 2014-02-25 Richard Kueng , David Gross

We use particle-in-cell (PIC) simulations of a collisionless, electron-ion plasma with a decreasing background magnetic field, $B$, to study the effect of velocity-space instabilities on the viscous heating and thermal conduction of the…

High Energy Astrophysical Phenomena · Physics 2018-02-27 Mario Riquelme , Eliot Quataert , Daniel Verscharen

Tuning parameters are parameters involved in an estimating procedure for the purpose of reducing the risk of some other estimator. Examples include the degree of penalization in penalized regression and likelihood problems, as well as the…

Statistics Theory · Mathematics 2026-03-31 Ingrid Dæhlen , Nils Lid Hjort , Ingrid Hobæk Haff

This work aims to estimate time-resolved velocity field that is directly associated with pressure fluctuations in a subsonic round jet. To achieve this goal, synchronous measurements of the velocity field and in-flow pressure fluctuations…

Fluid Dynamics · Physics 2021-06-15 Songqi Li , Lawrence Ukeiley

Nanoscale engineering and novel materials have created interesting effects in thermal transport. Thermal conductivity can now be different due to physical and heating sizes. Also, highly anisotropic thermal conductivity can result from…

Materials Science · Physics 2019-03-08 Ding Ding , Kedar Hippalgaonkar

Turbulence anisotropy was recently integrated into Monin-Obukhov Similarity Theory (MOST), extending its applicability to complex terrain and diverse surface conditions. Implementing this generalized MOST in numerical models, however,…

Fluid Dynamics · Physics 2025-03-20 Samuele Mosso , Karl Lapo , Ivana Stiperski

This paper contains the latest installment of the authors' project on developing ensemble based data assimilation methodology for high dimensional fluid dynamics models. The algorithm presented here is a particle filter that combines model…

Numerical Analysis · Mathematics 2020-04-22 Colin Cotter , Dan Crisan , Darryl Holm , Wei Pan , Igor Shevchenko

The optimal traverse of irregular terrains made by ground mobile robots heavily depends on the adequacy of the cost models used to plan the path they follow. The criteria to define optimality may be based on minimizing energy consumption…

We study anisotropic undersampling schemes like those used in multi-dimensional NMR spectroscopy and MR imaging, which sample exhaustively in certain time dimensions and randomly in others. Our analysis shows that anisotropic undersampling…

Information Theory · Computer Science 2018-03-20 Hatef Monajemi , David L. Donoho