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),...
Circadian rhythms — physiological, behavioral, and metabolic oscillations with an approximate 24-h period — are controlled by an evolutionarily conserved set of core clock genes operating at the transcriptional and protein level. Entrainable by Zeitgebers (external environmental stimuli such as light, temperature, and food) that modulate time-of-day specific functions, the...
Modern data sets are increasingly vast, not only in the number of samples, but also in the number of measurements, or features, that they contain. This high-dimensionality poses a unique set of problems for data analysis due to a set of phenomena known as ``the curse of dimensionality.'' This thesis...
Recently, machine learning and deep learning, which have made many theoretical and empir- ical breakthroughs and is widely applied in various fields, attract a great number of researchers and practitioners. They have become one of the most popular research directions and plays a sig- nificant role in many fields, such...
Existing nonlinear optimization methods have proven reliable over the past few decades for a wide range of applications but have critically relied on accurate function and gradient evaluations. Modern nonlinear optimization problems arising from machine learning and scientific computing applications are increasingly complex and large scale, which make accurate evaluations...
Processing of sensory information in the brain is a pervasive and fundamental phenomenon across animal species and is involved in both "hard-wired" innate responses as well as learned and adaptive behaviors. Here, I show that the avoidance of hot temperature, a simple innate behavior, contains unexpected plasticity and complex processing...
The focus on this thesis is on the dynamics of colloidal particles in an applied electric field in a uniform bulk fluid and on a fluid-fluid interface. In a bulk fluid, the dynamics of an isolated particle, one pair, and a cluster of particles under an applied nonuniform electric field...
With neurons as its primary computational components, the brain operates at multiple timescales. In this thesis, we focus on two timescales: on a relatively slow timescale on the order of hours to days, the brain adapts to the environment it is exposed to and learns its circuitry by altering the...
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...
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...