Rose-Hulman Institute of Technology
AAR Aerospace Consulting, LLC
University of Nebraska-Lincoln
Marshall University
Application Of Optimization Methods To Crack Profile Inversion Using Eddy Currents,
2017
Iowa State University
Application Of Optimization Methods To Crack Profile Inversion Using Eddy Currents, John R. Bowler, Wei Zhang, Aleksandar Dogandžić
John R. Bowler
A numerical scheme for finding crack shapes from eddy current measurements has been developed based on a startdard iterative inversion approach in which a nonlinear least squares objective function quantifying the overall difference between predictions and measurements is minimized. In this paper, steepest descent and conjugate‐gradient methods for minimizing the objective function are investigated and compared. Cramér‐Rao lower bounds on the crack parameters are derived to quantify the accuracy of the estimated crack shape. Cramér‐Rao bounds are also used to indicate improvements in the design of eddy‐current nondestructive evaluation systems.
Balanced Excitation And Inhibition Shapes The Dynamics Of A Neuronal Network For Movement And Reward,
2017
State University of New York at New Paltz
Balanced Excitation And Inhibition Shapes The Dynamics Of A Neuronal Network For Movement And Reward, Anca R. Radulescu
Biology and Medicine Through Mathematics Conference
No abstract provided.
Applying Fmri Complexity Analyses To The Single-Subject: A Case Study For Proposed Neurodiagnostics,
2017
State University of New York at New Paltz
Applying Fmri Complexity Analyses To The Single-Subject: A Case Study For Proposed Neurodiagnostics, Anca R. Radulescu, Emily R. Hannon
Biology and Medicine Through Mathematics Conference
No abstract provided.
Application Of Symplectic Integration On A Dynamical System,
2017
East Tennessee State University
Application Of Symplectic Integration On A Dynamical System, William Frazier
Electronic Theses and Dissertations
Molecular Dynamics (MD) is the numerical simulation of a large system of interacting molecules, and one of the key components of a MD simulation is the numerical estimation of the solutions to a system of nonlinear differential equations. Such systems are very sensitive to discretization and round-off error, and correspondingly, standard techniques such as Runge-Kutta methods can lead to poor results. However, MD systems are conservative, which means that we can use Hamiltonian mechanics and symplectic transformations (also known as canonical transformations) in analyzing and approximating solutions. This is standard in MD applications, leading to numerical techniques known as symplectic ...
Comparing Methods Of Measuring Chaos In The Symbolic Dynamics Of Strange Attractors,
2017
Georgia State University
Comparing Methods Of Measuring Chaos In The Symbolic Dynamics Of Strange Attractors, James J. Scully
Georgia State Undergraduate Research Conference
No abstract provided.
Center Manifold Theory And Computation Using A Forward Backward Approach,
2017
College of William and Mary
Center Manifold Theory And Computation Using A Forward Backward Approach, Emily E. Schaal
Undergraduate Honors Theses
The center manifold, an object from the field of differential equations, is useful in describing the long time behavior of the system. The most common way of computing the center manifold is by using a Taylor approximation. A different approach is to use iterative methods, as presented in Fuming and Kupper, 1994, Dellnitz and Hohmann, 1997, and Jolly and Rosa, 2005. In particular, Jolly and Rosa present a method based on a discretization of the Lyapunov-Perron (L-P) operator. One drawback is that this discretization can be expensive to compute and have error terms that are difficult to control. Using a ...
P26. Global Exponential Stabilization On So(3),
2017
sberkane@uwo.ca
P26. Global Exponential Stabilization On So(3), Soulaimane Berkane
Western Research Forum
Global Exponential Stabilization on SO(3)
Nestt: A Nonconvex Primal-Dual Splitting Method For Distributed And Stochastic Optimization,
2017
Iowa State University
Nestt: A Nonconvex Primal-Dual Splitting Method For Distributed And Stochastic Optimization, Davood Hajinezhad, Mingyi Hong, Tuo Zhao, Zhaoran Wang
Mingyi Hong
We study a stochastic and distributed algorithm for nonconvex problems whose objective consists a sum N/ nonconvex Li/N/ smooth functions, plus a nonsmooth regularizer. The proposed NonconvEx primal-dual SpliTTing (NESTT) algorithm splits the problem into N/ subproblems, and utilizes an augmented Lagrangian based primal-dual scheme to solve it in a distributed and stochastic manner. With a special non-uniform sampling, a version of NESTT achieves e-1 stationary solution using...gradient evaluations, which can be up to O(N)/ times better than the (proximal) gradient descent methods. It also achieves Q-linear convergence rate for nonconvex l1 penalized quadratic problems with polyhedral ...
Parallel Successive Convex Approximation For Nonsmooth Nonconvex Optimization,
2017
Stanford University
Parallel Successive Convex Approximation For Nonsmooth Nonconvex Optimization, Mesiam Razaviyayn, Mingyi Hong, Zhi-Quan Luo, Jong-Shi Pang
Mingyi Hong
Consider the problem of minimizing the sum of a smooth (possibly non-convex) and a convex (possibly nonsmooth) function involving a large number of variables. A popular approach to solve this problem is the block coordinate descent (BCD) method whereby at each iteration only one variable block is updated while the remaining variables are held fixed. With the recent advances in the developments of the multi-core parallel processing technology, it is desirable to parallelize the BCD method by allowing multiple blocks to be updated simultaneously at each iteration of the algorithm. In this work, we propose an inexact parallel BCD approach ...
Hamiltonian Model For Coupled Surface And Internal Waves In The Presence Of Currents,
2017
Dublin Institute of Technology
Hamiltonian Model For Coupled Surface And Internal Waves In The Presence Of Currents, Rossen Ivanov
Articles
We examine a two dimensional fluid system consisting of a lower medium bounded underneath by a flatbed and an upper medium with a free surface. The two media are separated by a free common interface. The gravity driven surface and internal water waves (at the common interface between the media) in the presence of a depth-dependent current are studied under certain physical assumptions. Both media are considered incompressible and with prescribed vorticities. Using the Hamiltonian approach the Hamiltonian of the system is constructed in terms of ’wave’ variables and the equations of motion are calculated. The resultant equations of motion ...
A Physics-Based Approach To Modeling Wildland Fire Spread Through Porous Fuel Beds,
2017
University of Kentucky
A Physics-Based Approach To Modeling Wildland Fire Spread Through Porous Fuel Beds, Tingting Tang
Theses and Dissertations--Mechanical Engineering
Wildfires are becoming increasingly erratic nowadays at least in part because of climate change. CFD (computational fluid dynamics)-based models with the potential of simulating extreme behaviors are gaining increasing attention as a means to predict such behavior in order to aid firefighting efforts. This dissertation describes a wildfire model based on the current understanding of wildfire physics. The model includes physics of turbulence, inhomogeneous porous fuel beds, heat release, ignition, and firebrands. A discrete dynamical system for flow in porous media is derived and incorporated into the subgrid-scale model for synthetic-velocity large-eddy simulation (LES), and a general porosity-permeability model ...
Orbital Stability Results For Soliton Solutions To Nonlinear Schrödinger Equations With External Potentials,
2017
University of Kentucky
Orbital Stability Results For Soliton Solutions To Nonlinear Schrödinger Equations With External Potentials, Joseph B. Lindgren
Theses and Dissertations--Mathematics
For certain nonlinear Schroedinger equations there exist solutions which are called solitary waves. Addition of a potential $V$ changes the dynamics, but for small enough $||V||_{L^\infty}$ we can still obtain stability (and approximately Newtonian motion of the solitary wave's center of mass) for soliton-like solutions up to a finite time that depends on the size and scale of the potential $V$. Our method is an adaptation of the well-known Lyapunov method.
For the sake of completeness, we also prove long-time stability of traveling solitons in the case $V=0$.
Proceedings Of The 2nd Resrb 2017 Conference, June 19-21, Wrocław, Poland,
2016
Wroclaw University of Technology
Proceedings Of The 2nd Resrb 2017 Conference, June 19-21, Wrocław, Poland, Wojciech M. Budzianowski
Wojciech Budzianowski
No abstract provided.
Call For Abstracts - Resrb 2018, June 18-20, Brussels, Belgium,
2016
Wroclaw University of Technology
Call For Abstracts - Resrb 2018, June 18-20, Brussels, Belgium, Wojciech M. Budzianowski
Wojciech Budzianowski
No abstract provided.
Order Form Resrb 2018,
2016
Wroclaw University of Technology
Order Form Resrb 2018, Wojciech M. Budzianowski
Wojciech Budzianowski
No abstract provided.
Abstract Template Resrb 2018,
2016
Wroclaw University of Technology
Abstract Template Resrb 2018, Wojciech M. Budzianowski
Wojciech Budzianowski
No abstract provided.
Renewable Energy And Sustainable Development (Resd) Group,
2016
Wroclaw University of Technology
Renewable Energy And Sustainable Development (Resd) Group, Wojciech M. Budzianowski
Wojciech Budzianowski
No abstract provided.
C.V. - Wojciech Budzianowski,
2016
Wroclaw University of Technology
Noise, Chaos, And The Verhulst Population Model,
2016
University of Wyoming
Noise, Chaos, And The Verhulst Population Model, Laurel J. Leonhardt
Honors Theses AY 16/17
The history of Verhulst's logistic equation is discussed. Bifurcation diagrams and the importance of the discrete logistic equation in chaos theory are introduced. The results of adding noise to the discrete logistic equation are computed. Surprising linearity is discovered in the relationship between error bounds placed on the period two region and the amount of noise added to the system.
(Un)Stable Manifold Computation Via Iterative Forward-Backward Runge-Kutta Type Methods,
2016
College of William and Mary
(Un)Stable Manifold Computation Via Iterative Forward-Backward Runge-Kutta Type Methods, Dmitriy Zhigunov
Undergraduate Honors Theses
I present numerical methods for the computation of stable and unstable manifolds in autonomous dynamical systems. Through differentiation of the Lyapunov-Perron operator in [Casteneda, Rosa 1996], we find that the stable and unstable manifolds are boundary value problems on the original set of differential equation. This allows us to create a forward-backward approach for manifold computation, where we iteratively integrate one set of variables forward in time, and one set of variables backward in time. Error and stability of these methods is discussed.
