Latent Modes of Nonlinear Flows

Latent Modes of Nonlinear Flows
Author: Ido Cohen
Publisher: Cambridge University Press
Total Pages: 64
Release: 2023-05-31
Genre: Computers
ISBN: 1009323865

Extracting the latent underlying structures of complex nonlinear local and nonlocal flows is essential for their analysis and modeling. In this Element the authors attempt to provide a consistent framework through Koopman theory and its related popular discrete approximation - dynamic mode decomposition (DMD). They investigate the conditions to perform appropriate linearization, dimensionality reduction and representation of flows in a highly general setting. The essential elements of this framework are Koopman eigenfunctions (KEFs) for which existence conditions are formulated. This is done by viewing the dynamic as a curve in state-space. These conditions lay the foundations for system reconstruction, global controllability, and observability for nonlinear dynamics. They examine the limitations of DMD through the analysis of Koopman theory and propose a new mode decomposition technique based on the typical time profile of the dynamics.

Neural Dynamic Mode Decomposition

Neural Dynamic Mode Decomposition
Author: Kenneth Hall
Publisher:
Total Pages: 0
Release: 2022
Genre:
ISBN:

The promise of applied Koopman operator theory is to find a linear representation of nonlinear dynamics. A closely related problem is that of finding a linearizing coordinate transform. The dynamic mode decomposition (DMD) is a data-driven approach to finding the best-fit linear operator which advances a set of measurements forward in time. However, DMD lacks a notion of observables, or functions of the measured state, which are an essential element of the Koopman operator's ability to linearly represent the evolution of nonlinear flows. We introduce the neural dynamic mode decomposition (NDMD), a model which takes advantage of the representational power of deep learning to discover an optimal set of observables for performing Koopman analysis via the dynamic mode decomposition. The NDMD model is trained on a multi-part loss function which includes terms designed to enforce (a) linear dynamics in the latent space of observables, (b) accurate, recurrently generated forecasts of future states, and (c) latent states which contain sufficient information to recover the original states. We demonstrate NDMD on damped and undamped nonlinear pendulum systems, as well as damped and undamped Duffing oscillator systems. NDMD learns a shared latent space where each trajectory evolves linearly. Each trajectory has its own associated time dynamics. To find a single approximation of the Koopman operator which generalizes to all trajectories, we reformulate NDMD to use training samples containing non-sequential snapshots from multiple trajectories. We modify the loss function to accommodate the non-sequential snapshots, and provide a procedure to use the fully trained model to produce a single, global approximation of the Koopman operator. NDMD is a data-driven decomposition method which can discover intrinsic dynamics of nonlinear systems. We extend NDMD to perform time-series classification tasks using the eigenvalues from DMD in the latent space as input features to a neural network classifier. This approach, which we call NDMD with classification, incorporates a classifier network and feature engineering steps into the end-to-end NDMD optimization problem. We conclude with a demonstration of NDMD with classification on an object discrimination task from acoustic recordings.

Data-Driven Science and Engineering

Data-Driven Science and Engineering
Author: Steven L. Brunton
Publisher: Cambridge University Press
Total Pages: 615
Release: 2022-05-05
Genre: Computers
ISBN: 1009098489

A textbook covering data-science and machine learning methods for modelling and control in engineering and science, with Python and MATLAB®.

High Performance Computing

High Performance Computing
Author: Heike Jagode
Publisher: Springer Nature
Total Pages: 515
Release: 2021-11-12
Genre: Computers
ISBN: 303090539X

This book constitutes the refereed post-conference proceedings of 9 workshops held at the 35th International ISC High Performance 2021 Conference, in Frankfurt, Germany, in June-July 2021: Second International Workshop on the Application of Machine Learning Techniques to Computational Fluid Dynamics and Solid Mechanics Simulations and Analysis; HPC-IODC: HPC I/O in the Data Center Workshop; Compiler-assisted Correctness Checking and Performance Optimization for HPC; Machine Learning on HPC Systems;4th International Workshop on Interoperability of Supercomputing and Cloud Technologies;2nd International Workshop on Monitoring and Operational Data Analytics;16th Workshop on Virtualization in High-Performance Cloud Computing; Deep Learning on Supercomputers; 5th International Workshop on In Situ Visualization. The 35 papers included in this volume were carefully reviewed and selected. They cover all aspects of research, development, and application of large-scale, high performance experimental and commercial systems. Topics include high-performance computing (HPC), computer architecture and hardware, programming models, system software, performance analysis and modeling, compiler analysis and optimization techniques, software sustainability, scientific applications, deep learning.

Artificial Intelligence For Science: A Deep Learning Revolution

Artificial Intelligence For Science: A Deep Learning Revolution
Author: Alok Choudhary
Publisher: World Scientific
Total Pages: 803
Release: 2023-03-21
Genre: Computers
ISBN: 9811265682

This unique collection introduces AI, Machine Learning (ML), and deep neural network technologies leading to scientific discovery from the datasets generated both by supercomputer simulation and by modern experimental facilities.Huge quantities of experimental data come from many sources — telescopes, satellites, gene sequencers, accelerators, and electron microscopes, including international facilities such as the Large Hadron Collider (LHC) at CERN in Geneva and the ITER Tokamak in France. These sources generate many petabytes moving to exabytes of data per year. Extracting scientific insights from these data is a major challenge for scientists, for whom the latest AI developments will be essential.The timely handbook benefits professionals, researchers, academics, and students in all fields of science and engineering as well as AI, ML, and neural networks. Further, the vision evident in this book inspires all those who influence or are influenced by scientific progress.

Scientific and Technical Aerospace Reports

Scientific and Technical Aerospace Reports
Author:
Publisher:
Total Pages: 456
Release: 1995
Genre: Aeronautics
ISBN:

Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.