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We address data assimilation for linear and nonlinear dynamical systems via the so-called \emph{model reference adaptive system}. Continuing our theoretical developments in \cite{Tram_Kaltenbacher_2021}, we deliver the first practical…

Optimization and Control · Mathematics 2026-02-12 Benedikt Kaltenbach , Christian Aarset , Tram Thi Ngoc Nguyen

Data assimilation plays a crucial role in numerical modeling, enabling the integration of real-world observations into mathematical models to enhance the accuracy and predictive capabilities of simulations. This approach is widely applied…

Numerical Analysis · Mathematics 2024-11-08 Alexander Lobbe , Dan Crisan , Oana Lang

We propose a physics-aware machine learning method to time-accurately predict extreme events in a turbulent flow. The method combines two radically different approaches: empirical modelling based on reservoir computing, which learns the…

Fluid Dynamics · Physics 2019-12-24 Nguyen Anh Khoa Doan , Wolfgang Polifke , Luca Magri

The reduced-complexity models developed by Edward Lorenz are widely used in atmospheric and climate sciences to study nonlinear aspect of dynamics and to demonstrate new methods for numerical weather prediction. A set of inviscid Lorenz…

Atmospheric and Oceanic Physics · Physics 2024-09-13 Francesco Fedele , Cristel Chandre , Martin Horvat , Nedjeljka Žagar

Reduced-order dynamical models play a central role in developing our understanding of predictability of climate irrespective of whether we are dealing with the actual climate system or surrogate climate-models. In this context, the…

Geophysics · Physics 2021-03-11 B. T. Nadiga

In this paper, we study a simple hydrodynamical model showing abrupt flow reversals at random times. For a suitable range of parameters, we show that the dynamics of flow reversal is accurately described by stochastic differential…

Chaotic Dynamics · Physics 2009-11-10 Roberto Benzi

Various types of measurement techniques, such as Light Detection and Ranging (LiDAR) devices, anemometers, and wind vanes, are extensively utilized in wind energy to characterize the inflow. However, these methods typically gather data at…

Fluid Dynamics · Physics 2025-02-13 Chang Yan , Shengfeng Xu , Zhenxu Sun , Thorsten Lutz , Dilong Guo , Guowei Yang

In this article we develop further an algorithm for data assimilation based upon a shadowing refinement technique [de Leeuw et al., SIAM J. Appl. Dyn. Sys., 17 (2018)] to take partial observations into account. Our method is based on…

Optimization and Control · Mathematics 2020-11-13 Bart de Leeuw , Svetlana Dubinkina

Motivated by recent progress in data assimilation, we develop an algorithm to dynamically learn the parameters of a chaotic system from partial observations. Under reasonable assumptions, we rigorously establish the convergence of this…

Classical Analysis and ODEs · Mathematics 2021-08-20 Elizabeth Carlson , Joshua Hudson , Adam Larios , Vincent R. Martinez , Eunice Ng , Jared P. Whitehead

We infer both microscopic and macroscopic behaviors of a three-dimensional chaotic fluid flow using reservoir computing. In our procedure of the inference, we assume no prior knowledge of a physical process of a fluid flow except that its…

Computational Physics · Physics 2018-09-12 Kengo Nakai , Yoshitaka Saiki

Understanding and predicting people flow in urban areas is useful for decision-making in urban planning and marketing strategies. Traditional methods for understanding people flow can be divided into measurement-based approaches and…

Human-Computer Interaction · Computer Science 2024-01-18 Ryo Murata , Kenji Tanaka

Data assimilation (DA) aims at optimally merging observational data and model outputs to create a coherent statistical and dynamical picture of the system under investigation. Indeed, DA aims at minimizing the effect of observational and…

Data Analysis, Statistics and Probability · Physics 2022-01-05 Yumeng Chen , Alberto Carrassi , Valerio Lucarini

Atmospheric flows exhibit selfsimilar fluctuations on all scales(space-time) ranging from climate(kilometers/years) to turbulence(millimeters/seconds) manifested as fractal geometry to the global cloud cover pattern concomitant with inverse…

chao-dyn · Physics 2007-05-23 A. Mary Selvam

The use of data assimilation technique to identify optimal topography is discussed in frames of time-dependent motion governed by non-linear barotropic ocean model. Assimilation of artificially generated data allows to measure the influence…

Atmospheric and Oceanic Physics · Physics 2009-12-08 Eugene Kazantsev

Data assimilation (DA) plays a pivotal role in diverse applications, ranging from climate predictions and weather forecasts to trajectory planning for autonomous vehicles. A prime example is the widely used ensemble Kalman filter (EnKF),…

Dynamical Systems · Mathematics 2024-01-03 Mohamad Abed El Rahman Hammoud , Naila Raboudi , Edriss S. Titi , Omar Knio , Ibrahim Hoteit

Data assimilation (DA) addresses the problem of sequentially estimating the state of a dynamical system from noisy and incomplete observations. In this work, we employ a diffusion model as a world model to simulate and predict the system's…

Machine Learning · Statistics 2026-05-26 Lifu Wei , Yinuo Ren , Naichen Shi , Yiping Lu

This paper considers the ill-posed data assimilation problem associated with hyperbolic/parabolic systems describing 2D coupled sound and heat flow. Given hypothetical data at time T > 0, that may not correspond to an actual solution of the…

Numerical Analysis · Mathematics 2025-01-28 Alfred S. Carasso

Standard methods of data assimilation assume prior knowledge of a model that describes the system dynamics and an observation function that maps the model state to a predicted output. An accurate mapping from model state to observation…

Dynamical Systems · Mathematics 2019-05-22 Franz Hamilton , Tyrus Berry , Timothy Sauer

There is an urgent need to build models to tackle Indoor Air Quality issue. Since the model should be accurate and fast, Reduced Order Modelling technique is used to reduce the dimensionality of the problem. The accuracy of the model, that…

We employ detailed numerical simulations to probe the mechanism of flow reversals in two-dimensional turbulent convection. We show that the reversals occur via vortex reconnection of two attracting corner rolls having same sign of…

Fluid Dynamics · Physics 2015-06-05 Mani Chandra , Mahendra K. Verma