Robert Baraldi
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View article: ProxSTORM -- A Stochastic Trust-Region Algorithm for Nonsmooth Optimization
ProxSTORM -- A Stochastic Trust-Region Algorithm for Nonsmooth Optimization Open
We develop a stochastic trust-region algorithm for minimizing the sum of a possibly nonconvex Lipschitz-smooth function that can only be evaluated stochastically and a nonsmooth, deterministic, convex function. This algorithm, which we cal…
View article: Domain decomposition for integer optimal control with total variation regularization
Domain decomposition for integer optimal control with total variation regularization Open
Total variation integer optimal control problems admit solutions and necessary optimality conditions via geometric variational analysis. In spite of the existence of said solutions, algorithms which solve the discretized objective suffer f…
View article: Rapid Optimization of Total Variation with Applications in Imaging, Additive Manufacturing, and Qualification
Rapid Optimization of Total Variation with Applications in Imaging, Additive Manufacturing, and Qualification Open
Total Variation optimization penalizes the gradient of a control variable or state. While this work focuses on image processing in particular, it has also found applications in inverse problems and topology optimization. In image processin…
View article: Adaptive Randomized Sketching for Dynamic Nonsmooth Optimization
Adaptive Randomized Sketching for Dynamic Nonsmooth Optimization Open
Dynamic optimization problems arise in many applications, including optimal flow control, full waveform inversion, and medical imaging, where they are plagued by significant computational challenges. For example, memory is often a limiting…
View article: Tsunami Early Warning From Global Navigation Satellite System Data Using Convolutional Neural Networks
Tsunami Early Warning From Global Navigation Satellite System Data Using Convolutional Neural Networks Open
We investigate the potential of using Global Navigation Satellite System (GNSS) observations to directly forecast full tsunami waveforms in real time. We train convolutional neural networks to use less than 9 min of GNSS data to forecast t…
View article: Tsunami Early Warning from Global Navigation Satellite System Data using Convolutional Neural Networks
Tsunami Early Warning from Global Navigation Satellite System Data using Convolutional Neural Networks Open
We investigate the potential of using Global Navigation Satellite System (GNSS) observations to directly forecast full tsunami waveforms in real time. We train convolutional neural networks (CNNs) to use less than 9 minutes of GNSS data to…
View article: A LEVENBERG-MARQUARDT METHOD FOR NONSMOOTH REGULARIZED LEAST SQUARES
A LEVENBERG-MARQUARDT METHOD FOR NONSMOOTH REGULARIZED LEAST SQUARES Open
We develop a Levenberg-Marquardt method for minimizing the sum of a smooth nonlinear least-squar es term $f(x) = \tfrac{1}{2} \|F(x)\|_2^2$ and a nonsmooth term $h$. Both $f$ and $h$ may be nonconvex. Steps are computed by minimizing the s…
View article: Comparison of Machine Learning Approaches for Tsunami Forecasting from Sparse Observations
Comparison of Machine Learning Approaches for Tsunami Forecasting from Sparse Observations Open
We have explored various different machine learning (ML) approaches for forecasting tsunami amplitudes at a set of forecast points, based on hypothetical short-time observations at one or more observation points. As a case study, we chose …
View article: A Proximal Quasi-Newton Trust-Region Method for Nonsmooth Regularized Optimization
A Proximal Quasi-Newton Trust-Region Method for Nonsmooth Regularized Optimization Open
We develop a trust-region method for minimizing the sum of a smooth term $f$ and a nonsmooth term $h$), both of which can be nonconvex. Each iteration of our method minimizes a possibly nonconvex model of $f + h$ in a trust region. The mod…
View article: Basis Pursuit Denoise With Nonsmooth Constraints
Basis Pursuit Denoise With Nonsmooth Constraints Open
Level-set optimization formulations with data-driven constraints minimize a\nregularization functional subject to matching observations to a given error\nlevel. These formulations are widely used, particularly for matrix completion\nand sp…
View article: Relaxation algorithms for matrix completion, with applications to seismic travel-time data interpolation
Relaxation algorithms for matrix completion, with applications to seismic travel-time data interpolation Open
Travel time tomography is used to infer the underlying three-dimensional wavespeed structure of the Earth by fitting seismic travel time data collected at surface stations. Data interpolation and denoising techniques are important pre-proc…
View article: Validation of a Mathematical Model for Green Algae (Raphidocelis Subcapitata) Growth and Implications for a Coupled Dynamical System with Daphnia Magna
Validation of a Mathematical Model for Green Algae (Raphidocelis Subcapitata) Growth and Implications for a Coupled Dynamical System with Daphnia Magna Open
Toxicity testing in populations probes for responses in demographic variables to anthropogenic or natural chemical changes in the environment. Importantly, these tests are primarily performed on species in isolation of adjacent tropic leve…