Machine Learning Enabled Prediction of Atmospheric Optical Turbulence from No-reference Imaging

Machine Learning Enabled Prediction of Atmospheric Optical Turbulence from No-reference Imaging
Author: Skyler P. Schork
Publisher:
Total Pages: 0
Release: 2022
Genre: Atmospheric turbulence
ISBN:

Laser based communication and weapons systems are integral to maintaining the operational readiness and dominance of our Navy. Perhaps one of the most intransigent obstacles for such systems is the atmosphere. This is particularly true in the near-maritime environment. Atmospheric turbulence perturbs the propagation of laser beams as they are subject to fluctuations in the refractive index of air. As the beams travel through the atmosphere there is loss of irradiance on target, beam spread, beam wander, and intensity fluctuations of the propagating laser beam. The refractive index structure parameter, C2n, is a measure of the intensity of the optical turbulence along a path. If C2n can be easily and efficiently determined in an operating environment, the prediction of laser performance will be greatly enhanced. The goal of this research is to use image quality features in combination with machine learning techniques to accurately predict the refractive index structure parameter, C2n. In order to construct a machine learning model for the refractive index structure parameter, a series of image quality features were evaluated. Seven image quality features were selected, and have been applied to an image dataset of 34,000 individual exposures. This dataset, along with independently measured C2n values from a scintillometer as the supervised variable, were then used to train a variety of machine learning models. The models of particular interest to this research are the Generalized Linear Model, the Bagged Decision Tree, the Boosted Decision Tree, as well as the Random Forest Model. While the quantity of available training data had a significant impact on model performance, the findings indicate that image quality can be used to assist in the prediction of C2n, and that the machine learning models outperform the linear model.

A Machine-learning Model for Prediction of Optical Turbulence in Near-maritime Environments

A Machine-learning Model for Prediction of Optical Turbulence in Near-maritime Environments
Author: Christopher D. Jellen
Publisher:
Total Pages: 95
Release: 2020
Genre: Atmospheric turbulence
ISBN:

"As a beam propagates, it is subject to fluctuations in the refractive index of air. These effects can be modeled as optical turbulence. Optical turbulence limits the effectiveness of laser-based weapons and communication systems employed by the United States Navy. Models developed to predict optical turbulence through the structure constant Cn2 are sensitive to absolute air temperature. Existing models have, however, failed to accurately predict the rapid beam attenuation and corresponding high values of Cn2 observed in maritime and near-maritime environments. In response, data-driven machine learning models were developed to predict the refractive index structure parameter Cn2, and to explore the importance of various environmental factors on its prediction. The current study uses 15 months of Cn2 field measurements collected along an 890 m scintillometer link over the Severn River at the United States Naval Academy. Measures of optical turbulence are complemented by corresponding measurements of 12 environmental parameters. Fully data-driven models were trained, developed, and tested to enhance Cn2 prediction accuracy in the near-maritime environment. Analysis of these models resulted in better understanding of the relative importance of each environmental parameter in accurately predicting Cn2. To our knowledge, this is the first application of purely data-driven machine learning models for predicting Cn2 in the near-maritime environment." -- Report Documentation Page [Standard Form 298 (Rev. 8-98)].

Forecasting Atmospheric Turbulence Conditions from Prior Environmental Parameters Using Artificial Neural Networks

Forecasting Atmospheric Turbulence Conditions from Prior Environmental Parameters Using Artificial Neural Networks
Author: Mitchell Gene Grose
Publisher:
Total Pages: 99
Release: 2021
Genre:
ISBN:

Optical (atmospheric) turbulence (Cn2) is a highly stochastic process that can apply many adverse effects on imaging and laser propagation systems. Modeling atmospheric turbulence conditions has been proposed by physics-based models but they are unable to capture the many cases. Recently, machine learning surrogate models have been used to learn the relationship between local environmental (weather) and turbulence conditions. These models predict a turbulence strength at time t from weather at time t. This thesis proposes a technique to forecast four hours of future turbulence conditions at 30-minute intervals from prior environmental parameters using artificial neural networks. First, local weather and turbulence measurements are formatted to pairs of input sequence and output forecast. Next, a grid search is performed to find the best combination of model architecture and training parameters. The architectures investigated are the Multilayer Perceptron (MLP) and three variants of the Recurrent Neural Network (RNN). Finally, the selected model is applied to the test dataset and analyzed. It is shown that the model has generally learned the relationship between prior environmental and future turbulence conditions.

Clouds and Climate

Clouds and Climate
Author: A. Pier Siebesma
Publisher: Cambridge University Press
Total Pages: 421
Release: 2020-08-20
Genre: Mathematics
ISBN: 1107061075

Comprehensive overview of research on clouds and their role in our present and future climate, for advanced students and researchers.

Artificial Intelligence Methods in the Environmental Sciences

Artificial Intelligence Methods in the Environmental Sciences
Author: Sue Ellen Haupt
Publisher: Springer Science & Business Media
Total Pages: 418
Release: 2008-11-28
Genre: Science
ISBN: 1402091192

How can environmental scientists and engineers use the increasing amount of available data to enhance our understanding of planet Earth, its systems and processes? This book describes various potential approaches based on artificial intelligence (AI) techniques, including neural networks, decision trees, genetic algorithms and fuzzy logic. Part I contains a series of tutorials describing the methods and the important considerations in applying them. In Part II, many practical examples illustrate the power of these techniques on actual environmental problems. International experts bring to life ways to apply AI to problems in the environmental sciences. While one culture entwines ideas with a thread, another links them with a red line. Thus, a “red thread“ ties the book together, weaving a tapestry that pictures the ‘natural’ data-driven AI methods in the light of the more traditional modeling techniques, and demonstrating the power of these data-based methods.

An Introduction to Machine Learning

An Introduction to Machine Learning
Author: Gopinath Rebala
Publisher: Springer
Total Pages: 263
Release: 2019-05-07
Genre: Technology & Engineering
ISBN: 3030157296

Just like electricity, Machine Learning will revolutionize our life in many ways – some of which are not even conceivable today. This book provides a thorough conceptual understanding of Machine Learning techniques and algorithms. Many of the mathematical concepts are explained in an intuitive manner. The book starts with an overview of machine learning and the underlying Mathematical and Statistical concepts before moving onto machine learning topics. It gradually builds up the depth, covering many of the present day machine learning algorithms, ending in Deep Learning and Reinforcement Learning algorithms. The book also covers some of the popular Machine Learning applications. The material in this book is agnostic to any specific programming language or hardware so that readers can try these concepts on whichever platforms they are already familiar with. Offers a comprehensive introduction to Machine Learning, while not assuming any prior knowledge of the topic; Provides a complete overview of available techniques and algorithms in conceptual terms, covering various application domains of machine learning; Not tied to any specific software language or hardware implementation.

Introduction to Deep Learning

Introduction to Deep Learning
Author: Eugene Charniak
Publisher: MIT Press
Total Pages: 187
Release: 2019-01-29
Genre: Computers
ISBN: 0262039516

A project-based guide to the basics of deep learning. This concise, project-driven guide to deep learning takes readers through a series of program-writing tasks that introduce them to the use of deep learning in such areas of artificial intelligence as computer vision, natural-language processing, and reinforcement learning. The author, a longtime artificial intelligence researcher specializing in natural-language processing, covers feed-forward neural nets, convolutional neural nets, word embeddings, recurrent neural nets, sequence-to-sequence learning, deep reinforcement learning, unsupervised models, and other fundamental concepts and techniques. Students and practitioners learn the basics of deep learning by working through programs in Tensorflow, an open-source machine learning framework. “I find I learn computer science material best by sitting down and writing programs,” the author writes, and the book reflects this approach. Each chapter includes a programming project, exercises, and references for further reading. An early chapter is devoted to Tensorflow and its interface with Python, the widely used programming language. Familiarity with linear algebra, multivariate calculus, and probability and statistics is required, as is a rudimentary knowledge of programming in Python. The book can be used in both undergraduate and graduate courses; practitioners will find it an essential reference.

Aviation Turbulence

Aviation Turbulence
Author: Robert Sharman
Publisher: Springer
Total Pages: 529
Release: 2016-06-27
Genre: Technology & Engineering
ISBN: 331923630X

Anyone who has experienced turbulence in flight knows that it is usually not pleasant, and may wonder why this is so difficult to avoid. The book includes papers by various aviation turbulence researchers and provides background into the nature and causes of atmospheric turbulence that affect aircraft motion, and contains surveys of the latest techniques for remote and in situ sensing and forecasting of the turbulence phenomenon. It provides updates on the state-of-the-art research since earlier studies in the 1960s on clear-air turbulence, explains recent new understanding into turbulence generation by thunderstorms, and summarizes future challenges in turbulence prediction and avoidance.

Springer Handbook of Acoustics

Springer Handbook of Acoustics
Author: Thomas Rossing
Publisher: Springer Science & Business Media
Total Pages: 1179
Release: 2007-06-21
Genre: Science
ISBN: 0387304460

This is an unparalleled modern handbook reflecting the richly interdisciplinary nature of acoustics edited by an acknowledged master in the field. The handbook reviews the most important areas of the subject, with emphasis on current research. The authors of the various chapters are all experts in their fields. Each chapter is richly illustrated with figures and tables. The latest research and applications are incorporated throughout, including computer recognition and synthesis of speech, physiological acoustics, diagnostic imaging and therapeutic applications and acoustical oceanography. An accompanying CD-ROM contains audio and video files.

The GOES-R Series

The GOES-R Series
Author: Steven J. Goodman
Publisher: Elsevier
Total Pages: 306
Release: 2019-10-05
Genre: Science
ISBN: 0128143282

The GOES-R Series: A New Generation of Geostationary Environmental Satellites introduces the reader to the most significant advance in weather technology in a generation. The world’s new constellation of geostationary operational environmental satellites (GOES) are in the midst of a drastic revolution with their greatly improved capabilities that provide orders of magnitude improvements in spatial, temporal and spectral resolution. Never before have routine observations been possible over such a wide area. Imagine satellite images over the full disk every 10 or 15 minutes and monitoring of severe storms, cyclones, fires and volcanic eruptions on the scale of minutes. Introduces the GOES-R Series, with chapters on each of its new products Provides an overview of how to read new satellite images Includes full-color images and online animations that demonstrate the power of this new technology