This dissertation considers a periodically-forced 1-D Langevin equation that possesses two stable periodic solutions in the absence of noise. We aim at answering the question: is there a most likely noise-induced transition path between these periodic solutions that allows one to identify a preferred phase of the forcing when the...
For stochastic simulation optimization in a modern computing era, we introduce a new parallel framework for solving very large-scale problems using a ranking & selection (R&S) approach that simulates all systems or feasible solutions to provide a global statistical guarantee. We propose a parallel adaptive survivor selection (PASS) framework that...
Motivated by rhythms in the brain, we investigate the synchronization of noisy and all-to-all pulse-coupled oscillators. We consider a case where the oscillatory excursions are of varying amplitude and where only sufficiently large excursions result in the output pulses that drive the interactions between the oscillators. In the regime of...
We present two novel, computational models of biofilm growth within an experimental flow cell. First, we use asymptotic approximations to develop a reduced model that captures the large-scale dynamics within an entire flow cell. The reduced model's predicted growth and nutrient distribution are close to the values predicted by previous...
We present a biophysical model of GCaMP6f calcium fluorescence in CA1 pyramidal neuron dendrites based upon results from imaging and electrophysiology experiments. This work was completed using experimental results from the laboratory of Professor Daniel Dombeck, Department of Neurobiology. Constraining the model to reproduce different objectives --- from in-vitro and...
This dissertation is a review of three projects I worked on during my time in the Computational Photography Lab at Northwestern University. First, a source separation problem for the X-Ray Fluorescence images of painted works of art is addressed through the incorporation of Hyperspectral Reflectance data. Following this, a discussion...
Many industrial fluid flow problems involve the interaction between heavy, rigid objects and one or more fluid phases. For several decades, there has been a vested interest in simulating these fluid-structure interaction (FSI) problems in order to improve engineering design processes. However, numerical simulations of these problems can be challenging...
The ever growing desire for accurate estimation and efficient learning necessitates the efforts to quantitatively characterize uncertainties for models. In this thesis, four problems pertaining to uncertainty quantification are discussed: A sequential stopping framework of constructing fixed-precision confidence regions is proposed for a class of multivariate simulation problems where variance...
This dissertation presents two projects with the goal of understanding how to quantitatively describe biological data, particularly data that is highly dynamic. The first study presents an improved quantitative tool for the analysis of particulate trajectories. Particulate trajectory data appears in several different biological contexts, and the majority of analyses...
Mixing by cutting-and-shuffling (like that for a deck of cards or a Rubik's cube) is a paradigm that has not been studied in detail even though it can be applied in a variety of situations including the mixing of granular materials. Mathematically, cutting- and-shuffling is described by piecewise isometries (PWIs),...