Physical Sciences and Mathematics Commons^™

Algorithms For Robot Coverage Under Movement And Sensing Constraints, Jeremy S. Lewis

Theses and Dissertations

This thesis explores the problem of generating coverage paths—that is, paths that pass within some sensor footprint of every point in an environment—for mobile robots. It both considers models for which navigation is a solved problem but motions are constrained, as well for models in which navigation must be considered along with coverage planning because of the robot’s unreliable sensing and movements.

The motion constraint we adopt for the former is a common constraint, that of a Dubins vehicle. We extend previous work that solves this coverage problem as a traveling salesman problem (TSP) by introducing a practical heuristic algorithm …

Thermodynamically Consistent Hydrodynamic Phase Field Models And Numerical Approximation For Multi-Component Compressible Viscous Fluid Mixtures, Xueping Zhao

Theses and Dissertations

Material systems comprising of multi-component, some of which are compressible, are ubiquitous in nature and industrial applications. In the compressible fluid flow, the material compressibility comes from two sources. One is the material compressibility itself and another is the mass-generating source. For example, the compressibility in the binary fluid flows of non-hydrocarbon (e.g. Carbon dioxide) and hydrocarbons encountered in the enhanced oil recovery (EOR) process, comes from the compressibility of the gas-liquid mixture itself. Another example of the mixture of compressible fluids is growing tissue, in which cell proliferation and cell migration make the material volume changes so that it …

Interfacing Iconicity - Addressing Software Divarication Through Diagrammatic Design Principles, George Akhvlediani

Theses and Dissertations

This research examines conflicts accompanying the proliferation of computer technology and, more specifically, constellations of dependency in the always expanding volume of software, platforms, and the firms/individuals using them. We identify a pervasive phenomenon of “divarication” in the growing variety of progressively specialized systems and system roles. As software systems enter new thresholds of sophistication, they effectively aggregate many distinct components and protocols. Consequently, we are confronted with a diverse ecology of stratified and thereby incompatible software systems. Software inherits the limitations and potential flaws of its constituent parts, but unlike physical machinery, it isn’t readily disassembled in instances of …

Development Of A Fluorescence Imaging Photometer-Based Method For Characterization Of Phytoplankton Communities, Cameron Maxwell Rekully

Theses and Dissertations

The development of methods for real-time characterization of phytoplankton community structure has important implications for environmental monitoring and the prediction of harmful algal blooms. Our research group has developed an instrument, the Fluorescence Imaging Photometer (FIP), which is capable of rapid classification of phytoplankton via imaging single-cell chlorophyll a fluorescence under different excitation conditions. Discrimination of cells from different taxonomic groups is achieved using optical bandpass filters that have been chosen to selectively excite pigments which occur in characteristic ratios that vary from one group to the next. The relative fluorescence intensity emitted by cells under these different excitation conditions …

Hierarchical Corannulene-Based Materials, Allison M. Rice

Theses and Dissertations

Merging the intrinsic properties of fullerene (buckyball) and corannulene (buckybowl) derivatives with the inherent properties of crystalline metal- and covalent- organic frameworks (MOFs and COFs), including their modularity, porosity, versatility, high surface area, and structural tunability, opens a pathway to unlock a novel class of fulleretic materials. Despite the great interest in MOFs and COFs, as well as fullerene derivatives, this dissertation is focused on crystalline fullerene- and corannulene- containing frameworks, highlighting their potential contributions in the fields of optoelectronic devices, electrodes, and photosensitizers. We have revealed a dual role of fullerene- and corannulene-containing building blocks showing their versatility to …

Current Induced Depairing And Mixed State Behavior In The Bite/Fete Interfacial Superconductor, Charles Louis Dean Ii

Theses and Dissertations

The Bi2Te3/FeTe heterostructure intersects several phenomena and key classes of materials in condensed matter physics: topological insulators, superconductivity, magnetism, and the physics of interfaces. While neither the topological insulator (BiTe) nor the iron chalcogenide (FeTe) are themselves superconductors, superconductivity forms in a thin 7nm interfacial layer between the two. The restricted dimensionality and the extraordinarily conductive normal state, possibly sourced by the topologically protected surface states, have led to the observation of novel phenomena such as the Likharev vortex explosion and transitions in behavior resulting from the interplay between current induced depairing and the Berezinski-Kosterlitz-Thouless regime. The measured depairing current …

Phylogeny, Ancestral Genome, And Disease Diagnoses Models Constructions Using Biological Data, Bing Feng

Theses and Dissertations

Studies of bioinformatics develop methods and software tools to analyze the biological data and provide insight of the mechanisms of biological process. Machine learning techniques have been widely used by researchers for disease prediction, disease diagnosis, and bio-marker identification. Using machine-learning algorithms to diagnose diseases has a couple of advantages. Besides solely relying on the doctors’ experiences and stereotyped formulas, researchers could use learning algorithms to analyze sophisticated, high-dimensional and multimodal biomedical data, and construct prediction/classification models to make decisions even when some information was incomplete, unknown, or contradictory. In this study, first of all, we built an automated computational …

Local Rings And Golod Homomorphisms, Thomas Schnibben

Theses and Dissertations

The Poincaré series of a local ring is the generating function of the Betti numbers for the residue field. The question of when this series represents a rational function is a classical problem in commutative algebra. Golod rings were introduced by Golod in 1962 and are one example of a class of rings that have rational Poincaré series. The idea was generalized to Golod homomorphisms by Levin in 1975.

In this paper we prove two homomorphisms are Golod. The first is a class of ideals such that the natural projection to the quotient ring is a Golod homomorphism. The second …

Semiparametric Statistical Estimation And Inference With Latent Information, Qianqian Wang

Theses and Dissertations

In Chapter 1, we predicted disease risk by transformation models in the presence of missing subgroup identifiers. When a discrete covariate defining subgroup membership is missing for some of the subjects in a study, the distribution of the outcome follows a mixture distribution of the subgroup-specific distributions. Taking into account the uncertain distribution of the group membership and the covariates, we model the relation between the disease onset time and the covariates through transformation models in each sub-population, and develop a nonparametric maximum likelihood based estimation implemented through EM algorithm along with its inference procedure. We further propose methods to …

Special Fiber Rings Of Certain Height Four Gorenstein Ideals, Jaree Hudson

Theses and Dissertations

Let S be a set of four variables, k a field of characteristic not equal to two such that k contains all square roots, and I a height four Gorenstein ideal of k[S] generated by nine quadratics so that I has a Gorenstein-linear resolution. We define a complex X• so that each module of X• is the tensor product of a certain polynomial ring Q in nine variables and a direct sum of indecomposable k[Sym(S)]-modules and the differential maps are Q- and k[Sym(S)]-module homomorphisms. Work with the Macaulay2 software suggests that H0(X•) is the special fiber ring of I and …

The Impact Of Upland Development And Marsh Width On Groundwater Composition In Estuarine Tidal Creeks In The Southeastern Coastal United States, Meghan Shanahan

Theses and Dissertations

Coastal upland development has been shown to negatively impact surface water quality in tidal creeks along the southeastern coastal United States, but the impact of development on groundwater quality is not well understood. Increases in impervious cover associated with development has the potential to increase groundwater contamination as well as reduce fresh rainwater infiltration into the subsurface, which may decrease discharge of fresh groundwater to the estuary. We hypothesized that groundwater nutrient concentrations and salinity ranges would be higher in developed watersheds than in undeveloped watersheds.

Groundwater discharging from coastal uplands often travels through salt marshes before discharging to tidal …

Cationic Metallocene-Containing Biomaterials For Antimicrobial Applications, Parasmani Pageni

Theses and Dissertations

Metal-containing polymers or metallopolymers, are one of the major classes of polymers which stand out independently because of a unique combination of organic and inorganic components in one macromolecular system. Among the variety of metallopolymers, metallocene-containing polymers have been widely utilized for applications ranging from electrochemical sensors to templates for advanced inorganic catalysts to battery materials, due to their unique physicochemical properties. This dissertation is focused on the synthesis, characterization, and application of cationic metallocene-containing polymeric materials. Cationic-cobaltocenium was grafted in various inorganic nanoparticles using polymerization techniques such as reversible addition-fragmentation chain transfer polymerization.

In Chapter 1, the overall background …

Impacts Of Drainage Systems On Stormwater Hydrology: Rocky Branch Watershed, Columbia, South Carolina, Logan Ress

Theses and Dissertations

The effects of urbanization and associated land use changes, specifically increases in impervious surfaces, have long been the focal point of urban hydrologic research. However, studies and calculations that consider impervious surfaces alone do not encompass all factors that influence urban hydrologic response. Artificial structures such as storm sewer (SS) systems and road networks increase rates of stormwater conveyance, yet these artificial networks are rarely considered in computations of drainage densities and associated hydrologic alterations. This study examines several hydrologically relevant descriptors that can be used to better understand the impact of urbanization on small watersheds. Rainfall and stormflow data …

Design, Synthesis, Characterization, And Applications Of Matrix Free Polymer Nanocomposites, Yucheng Huang

Theses and Dissertations

This dissertation focuses on the design, synthesis, characterization and application of matrix free polymer nanocomposites. Reversible addition-fragmentation chain transfer (RAFT) polymerization was used to synthesize block copolymers and polymer grafted silica nanoparticles with precise control over architectures.

In the first chapter, thermoplastic elastomer (TPE) grafted nanoparticles were prepared by grafting block copolymer poly(styrene-block-(n-butyl acrylate)) onto silica nanoparticles (NPs) (~15nm) via surface initiated RAFT polymerization. The effects of polymer chain length and graft density on the mechanical properties were investigated using films made solely from the grafted NPs. The ultimate tensile stress and elastic modulus increased with the increase of PS …

Instrumentation For, And Application Of, Novel Electrochemical Tools For In Vivo Analysis Of Neurotransmitters In The Context Of Psychiatric Disease, Rhiannon Robke

Theses and Dissertations

ABSTRACTSerotonin’s involvement in many physiological processes including anxiety, stress, compulsivity, and mood has been speculated for decades. Insufficient progress in our understanding of serotonin chemistry is due to the lack of effective tools to selectively measure this neurotransmitter on a neurotransmission-relevant time scale in vivo. An analytical technique for serotonin measurements, fast-scan cyclic voltammetry (FSCV), was pioneered in the last decade in anesthetized rodents and is beginning to shed light on the complexity of serotonergic activity on a sub-second timescale. Complementary, more recent technological innovations have enabled ambient neurotransmitter levels to be determined every few seconds using a method called …

Iron Transport Machinery: A Potential Therapeutic Target In Escherichia Coli, Clorissa L. Washington – Hughes

Theses and Dissertations

Iron metabolism is an integral part of life for most organisms. Despite its essentiality, iron can also become toxic. There are many aspects to maintaining iron balance within the cell. The aim of this work is to provide insight into the function of several components involved in bacterial iron homeostasis. This work is significant for the development of novel antibiotics for treating resistant or pathogenic bacteria. Herein, it is shown that nickel can disrupt normal bacterial iron metabolism and that bacterial resistance can be affected by expression of iron acquisition genes. Once iron is obtained by the cell, it can …

Effectiveness Of Conventional And Lid Stormwater Management Approaches With Swmm Modeling: Rocky Branch Watershed, Columbia, Sc, John M. Williams

Theses and Dissertations

Increases in percent impervious area and storm-sewer densities in an urbanized watershed lead to increased flood risk in urban areas. Conventional flood-risk management strategies such as detention ponds and low impact development (LID) can reduce peak flows. Research is needed to resolve questions about which strategy is best-suited for stormwater management under various schemes of sizing, distribution, and cost. Conventional and LID strategies differ in associated costs and benefits in addition to effectiveness and location feasibility. Previous research suggests that conventional strategies require less initial investment for design and construction, though LID is more cost effective in the long-term due …

Designed Polymer Brush Interfaces For Plutonium Separations And Polyethylene Nanocomposites, Julia G. Pribyl

Theses and Dissertations

Modification of surfaces with polymer brushes has become an important area of research for developing materials with a variety of advanced properties. Flat or continuous surfaces modified with polymer brushes can serve as surfaces where chemical reactions or separations take place, and discrete nanoparticles covered in a polymer brush can disperse within a miscible surrounding polymer, generating a composite which retains the processability of the polymer but becomes endowed with the properties of the filler as well. Presented herein are new synthetic approaches to modify both continuous surfaces as well as discrete particles with polymer brushes for complex applications. In …

An Axion Search With The Majorana Demonstrator, Clinton Gray Wiseman

Theses and Dissertations

The Majorana Demonstrator is an array of P-type point contact (PPC) germanium detectors enclosed in a multi-layered shield at the 4850’ level of the Sanford Underground Research Facility. Its primary goal is to search for the neutrinoless double beta decay of 76Ge. The initial 10 kg-y dataset, taken over a two year period, has energy thresholds as low as 1 keV. This allows concurrent rare event searches for the signatures of dark matter and solar axions in the low energy spectrum. Though the detectors are routinely operated with sub-keV energy thresholds, changing noise conditions in the array have made it …

Machine Learning Based Disease Gene Identification And Mhc Immune Protein-Peptide Binding Prediction, Zhonghao Liu

Theses and Dissertations

Machine learning and deep learning methods have been increasingly applied to solve challenging and important bioinformatics problems such as protein structure prediction, disease gene identification, and drug discovery. However, the performances of existing machine learning based predictive models are still not satisfactory. The question of how to exploit the specific properties of bioinformatics data and couple them with the unique capabilities of the learning algorithms remains elusive. In this dissertation, we propose advanced machine learning and deep learning algorithms to address two important problems: mislocation-related cancer gene identification and major histocompatibility complex-peptide binding affinity prediction. Our first contribution proposes a …

Inorganic Nanocrystals And Their Applications In Hybrid 0d:2d Material Optoelectronics, Mathew Kelley

Theses and Dissertations

Functional nanomaterials have garnered great interest as candidates for use in next-generational optoelectronics such as solar photovoltaics, light-emitting diodes, and photodetectors. Among these low-dimensional materials, hybrid devices employing both 0D and 2D materials are of interest due to exploitation of the favorable characteristics of each component, and performances superior to standalone counterparts are achievable. This thesis is divided into two parts, as follows. The first two chapters will introduce lowdimensional materials and their favorable characteristics; our work on the formation of ligand-exchanged nanocrystal thin films purified by gel-permeation chromatography will also be discussed. In the second component, the formation and …

Adjusting For Mis-Reporting In Count Data, Gelareh Rahimighazikalayeh

Theses and Dissertations

Any counting system is prone to recording errors including underreporting and overreporting. Ignoring the misreporting pattern in count data can give rise to bias in the estimation of model parameters. Accordingly, Poisson, negative binomial and generalized Poisson regression have been expanded in some instances to capture reporting biases. However, to our knowledge, no program has been developed to allow users to apply all of these models when needed. In the first part of the dissertation, we review the available models for underreported counts and develop a Stata command to estimate Poisson, negative binomial and generalized Poisson regression models for underreported …

Fabrication And Application Of Functional Polymer-Protein Coreshell Nanoparticles, Lin Lu

Theses and Dissertations

The study of polymer-protein nanoparticles is of increasing interest due to their various potential applications in biosensing, imaging, bioseparations, gene and drug delivery, etc. Synthetic polymers can be tailored with different functional groups and properties, therefore, they can serve as platforms to impart proteins with additional features and assist proteins to better perform biological functions. In this dissertation work, we were mainly focusing on the preparation of polymer-protein core-shell nanoparticles by synthesizing new functional polymers and assembling them with proteins for different applications. In chapter 1, a pyridine grafted diblock copolymer P(CL-g-Py)-b-PCL was prepared through ROP and CuAAC reactions. …

Classical And Quantum Kac’S Chaos, Rade Musulin

Theses and Dissertations

In 1956 Kac studied the Boltzmann equation, an integro-differential equation which describes the density function of the distribution of the velocities of the molecules of dilute monoatomic gases under the assumption that the energy is only transferred via collisions between the molecules. In an attempt at a solution to the Boltzmann equation, Kac introduced a property of the density function that he called the “Boltzmann property" which describes the behavior of the density function at a given fixed time as the number of particles tends to infinity. The Boltzmann property has been studied extensively since then, and has been abstracted …

Improving Speech-Related Facial Action Unit Recognition By Audiovisual Information Fusion, Zibo Meng

Theses and Dissertations

In spite of great progress achieved on posed facial display and controlled image acquisition, performance of facial action unit (AU) recognition degrades significantly for spontaneous facial displays. Furthermore, recognizing AUs accompanied with speech is even more challenging since they are generally activated at a low intensity with subtle facial appearance/geometrical changes during speech, and more importantly, often introduce ambiguity in detecting other co-occurring AUs, e.g., producing non-additive appearance changes. All the current AU recognition systems utilized information extracted only from visual channel. However, sound is highly correlated with visual channel in human communications. Thus, we propose to exploit both audio …

Bayesian Semiparametric Methods For Analyzing Panel Count Data, Jianhong Wang

Theses and Dissertations

Panel count data commonly arise in epidemiological, social science, medical studies, in which subjects have repeated measurements on the recurrent events of interest at different observation times. Since the subjects are not under continuous monitoring, the exact times of those recurrent events are not observed but the counts of such events within the adjacent observation times are known. Panel count data can be considered as a special type of longitudinal data with a count response variable in the literature. Compared to the frequentist literature, very limited Bayesian approaches have been developed to analyze panel count data. In this dissertation, several …

Estimation Procedures For Complex Survival Models And Their Applications In Epidemiology Studies, Jie Zhou

Theses and Dissertations

In this dissertation, we aim to address three important questions in practice, which can be solved through complex survival models. The first project focuses on studying the longitudinal fitness effect on cardiovascular disease (CVD) mortality. In the second project, we study the disease-death relation between CVD and all-cause mortality and evaluate important covariate effects on the disease or death transitions. In the third project, we compare antiretroviral treatment (ART) for HIV patients and consider both treatment effect and side effect of the drugs. The first two projects are motivated by the Aerobics Center Longitudinal Study (ACLS) datasets and the third …

Two-Electrode Measurements Of Electrostatic Double Layer Potentials With Atomic Force Microscopy, Jason Giamberardino

Theses and Dissertations

In this dissertation, I provide a thorough description of my development of theoretical, analytical, and experimental techniques pertaining to novel measurements of the electrostatic double layer (EDL) using atomic force microscopy (AFM), among other techniques. The EDL refers to the structure formed by ions that exists at the interface between a solid and a liquid. The EDL is an important physical element of many systems and its behavior has been of interest to scientists for many decades. Because many areas of science and engineering are moving to test, build, and understand systems at smaller and smaller scales, this work focuses …

Authenticating Users With 3d Passwords Captured By Motion Sensors, Jing Tian

Theses and Dissertations

Authentication plays a key role in securing various resources including corporate facilities or electronic assets. As the most used authentication scheme, knowledgebased authentication is easy to use but its security is bounded by how much a user can remember. Biometrics-based authentication requires no memorization but ‘resetting’ a biometric password may not always be possible. Thus, we propose study several behavioral biometrics (i.e., mid-air gestures) for authentication which does not have the same privacy or availability concerns as of physiological biometrics.

In this dissertation, we first propose a user-friendly authentication system Kin- Write that allows users to choose arbitrary, short and …

Investigation Of The Spatial Dependence Of Carrier Dynamics In Semiconductor Optoelectronic Devices, Bobby G. Barker Jr.

Theses and Dissertations

Optoelectronic devices, such as solar cells and photodetectors, rely on separating and transporting charge through semiconductors that have excess electron-hole pairs created by photon absorption. This talk will focus of several different semiconductor materials of various dimensionality, such as lead halide perovskites, wide bandgap SiC, graphene, semiconductor nanowires (NWs), and quantum dots (QDs).

The results of Chapter 2 demonstrate the dependence of the perovskite/hole transport layer on carrier transport of perovskite films for solar cells. Efficient charge separation at the interfaces of the perovskite with the carrier transport layers is crucial for perovskite solar cells to achieve high power conversion …