Physical Sciences and Mathematics Commons^™

Email Similarity Matching And Automatic Reply Generation Using Statistical Topic Modeling And Machine Learning, Zachery L. Schiller

Electronic Theses and Dissertations

Responding to email is a time-consuming task that is a requirement for most professions. Many people find themselves answering the same questions over and over, repeatedly replying with answers they have written previously either in whole or in part. In this thesis, the Automatic Mail Reply (AMR) system is implemented to help with repeated email response creation. The system uses past email interactions and, through unsupervised statistical learning, attempts to recover relevant information to give to the user to assist in writing their reply.

Three statistical learning models, term frequency-inverse document frequency (tf-idf), Latent Semantic Analysis (LSA), and Latent Dirichlet …

Los Morteros: Early Monumentality And Environmental Change In The Lower Chao Valley, Northern Peruvian Coast, Ana Cecilia Mauricio Llonto

Electronic Theses and Dissertations

This doctoral dissertation presents the results of archaeological and geoarchaeological studies carried out at the site of Los Morteros and the Archaeological Complex of Pampa de las Salinas, lower Chao Valley, North Coast of Peru, between September 2012 and July 2014. This research focuses on the study of the mound-shaped site of Los Morteros and the environmental contexts in which this site developed. Previous excavations at the site considered Los Morteros as a “stabilized dune” whose top was used as cemetery for pre-pottery people around cal. 5000 B.P (Cardenas 1995, 1999). However, geo-radar explorations of the mound in 2006 and …

The Number Of Zeros Of A Polynomial In A Disk As A Consequence Of Coefficient Inequalities With Multiple Reversals, Derek T. Bryant

Electronic Theses and Dissertations

In this thesis, we explore the effect of restricting the coefficients of polynomials on the bounds for the number of zeros in a given region. The results presented herein build on a body of work, culminating in the generalization of bounds among three classes of polynomials. The hypotheses of monotonicity on each class of polynomials were further subdivided into sections concerning r reversals among the moduli, real parts, and both real and imaginary parts of the coefficients.

River Restoration: Institutions, Boundaries, And Social Ecological Dynamics, Eileen Sylvan Johnson

Electronic Theses and Dissertations

This human dimensions research, consisting of three manuscripts, explores the social and ecological dimensions of river restoration through an examination of the restoration trajectories of the Androscoggin, an impaired system, and the Kennebec, a restored system. Manuscript one examines the influence of biophysical and community attributes and institutional rules on policy stakeholders goals and actions within the two watersheds. For manuscripts one and two, we conducted semi-structured interviews with key informants, assembled documents pertaining to restoration actions, and conducted participant observation at stakeholder meetings. We qualitatively analyzed transcripts and documents. Results suggest that policy stakeholders’ understandings of biophysical and community …

Biogeography And Conservation Of Tidal Marsh Bird Communities Across A Changing Landscape, Maureen D. Correll

Electronic Theses and Dissertations

Given the current mass extinction crisis and continued fragmentation of resources worldwide, the outlook is dire for global biodiversity. Rising global temperature, sea levels, and storm frequency all create environmental conditions that can drive change in species abundance and distribution across a landscape. Those species reliant upon a single type of habitat and resource for survival, termed “specialists”, are particularly vulnerable to change due to their inability to utilize a variety of resources well. As a result, specialism is now considered one of the dominant factors determining extinction of species. In this dissertation I explore the effects of disturbance on …

The Unique Electrochemical Reactivity Of Small Metal Nanoparticles., Rafael A. Masitas

Electronic Theses and Dissertations

This dissertation describes the factors controlling metal nanoparticle (NP) oxidation, using Au oxidation in Br- and Ag oxidation in acid as model systems. We found that the oxidation potential depends on size, surface charge, and electrode material. Size has a dramatic effect, shifting about 200 mV from > 200 nm diameter down to 4 nm diameter. The shift is more dramatic below 4 nm. 2.3 nm average diameter Au NPs oxidized in the 300-500 mV range and 1.5 nm average diameter Au NPs displayed several sharp peaks from 200 mV to as low as -200 mV. These smallest Au NPs show …

Fluvial Deposition, El Nino And Landscape Construction In Northern Coastal Peru, Paul M. Pluta

Electronic Theses and Dissertations

The El Nino global climate anomaly is a major cause of weather variation that can have far-reaching effects on human populations around the world. Northern coastal Peru is an area of historically major impacts where strong El Nino events have resulted in catastrophic flooding and mass wasting, leading to significant social disruption. There is a growing body of literature on the prehistoric chronology of El Nino and how it affected human populations of the past, but more work is needed. In order to address the timing and characteristics of past El Nino events I investigated the alluvial sedimentary sequences at …

Predicting Intraday Financial Market Dynamics Using Takens' Vectors; Incorporating Causality Testing And Machine Learning Techniques, Abubakar-Sadiq Bouda Abdulai

Electronic Theses and Dissertations

Traditional approaches to predicting financial market dynamics tend to be linear and stationary, whereas financial time series data is increasingly nonlinear and non-stationary. Lately, advances in dynamical systems theory have enabled the extraction of complex dynamics from time series data. These developments include theory of time delay embedding and phase space reconstruction of dynamical systems from a scalar time series. In this thesis, a time delay embedding approach for predicting intraday stock or stock index movement is developed. The approach combines methods of nonlinear time series analysis with those of causality testing, theory of dynamical systems and machine learning (artificial …

On Properties Of RW-Regular Graphs, Franklina Samani

Electronic Theses and Dissertations

If every vertex in a graph G has the same degree, then the graph is called a regular graph. That is, if deg(v) = r for all vertices in the graph, then it is denoted as an r-regular graph. A graph G is said to be vertex-weighted if all of the vertices are assigned weights. A generalized definition for degree regularity for vertex-weighted graphs can be stated as follows: A vertex-weighted graph is said to be r_w-regular if the sum of the weights in the neighborhood of every vertex is r_w. If all vertices are assigned …

Assessing The Physical Security Of Idfs With Psatool: A Case Study, Sulabh Bista

Electronic Theses and Dissertations

PSATool is a checklist-based, web-based application for assessing the physical security of Intermediate Distribution Frameworks. IDFs, or wiring closets, are an integral if often neglected component of information security. Earlier work by Timbs (2013) identified 52 IDF-related security requirements based on federal and international standards for physical security. PSATool refines Timbs’ prototype application for IDF assessment, extending it with support for mobile-device-based data entry.

PSATool was used to assess 25 IDFs at a regional university, a college and a manufacturing corporation, with an average of 9 minutes per assessment. Network managers and assessors involved in the assessments characterized PSATool as …

Electrochemical Formation Of One-Dimensional Metal Nanostructures Across Microgaps Electrodes For Resistive Switching And Optical Sensing Applications., Nidhi Shah

Electronic Theses and Dissertations

This dissertation focuses on the electrochemical formation of one-dimensional (1D) Ag nanostructures (in particular nanowires and nanochains) directly on electrode surfaces or gap of two electrodes. Ag nanowires (NWs) and nanorods (NRs) grow directly on glass/indium tin oxide (ITO) surfaces from electrode-attached Au nanoparticle seeds in the presence of cetyltrimethylammonium bromide (CTAB) at appropriate potentials with a 5-15 % yield and the average length ranging from 100 nm to 3 µm for growth times of 30 to 120 min. This method failed when trying to grow Ag NRs/NWs across 5 µm Au electrode gaps. Interestingly, applying voltage in air leads …

Spreading Speeds And Traveling Waves In Some Population Models., Quancheng Meng

Electronic Theses and Dissertations

Virtually every ecosystem has been invaded by exotic organisms with potentially drastic consequences for the native fauna or flora. Studying the forms and rates of invading species has been an important topic in spatial ecology. We investigate two two-species competition models with Allee effects in the forms of reaction-diffusion equations and integro-difference equations. We discuss the spatial transitions from a mono-culture equilibrium to a coexistence equilibrium or a different mono-culture equilibrium in these models. We provide formulas for the spreading speeds based on the linear determinacy and show the results on the existence of traveling waves. We also study a …

Multiple Instance Fuzzy Inference., Amine Ben Khalifa

Electronic Theses and Dissertations

A novel fuzzy learning framework that employs fuzzy inference to solve the problem of multiple instance learning (MIL) is presented. The framework introduces a new class of fuzzy inference systems called Multiple Instance Fuzzy Inference Systems (MI-FIS). Fuzzy inference is a powerful modeling framework that can handle computing with knowledge uncertainty and measurement imprecision effectively. Fuzzy Inference performs a non-linear mapping from an input space to an output space by deriving conclusions from a set of fuzzy if-then rules and known facts. Rules can be identified from expert knowledge, or learned from data. In multiple instance problems, the training data …

Spatiotemporal Wireless Sensor Network Field Approximation With Multilayer Perceptron Artificial Neural Network Models, François Neville

Electronic Theses and Dissertations

As sensors become increasingly compact and dependable in natural environments, spatially-distributed heterogeneous sensor network systems steadily become more pervasive. However, any environmental monitoring system must account for potential data loss due to a variety of natural and technological causes. Modeling a natural spatial region can be problematic due to spatial nonstationarities in environmental variables, and as particular regions may be subject to specific influences at different spatial scales. Relationships between processes within these regions are often ephemeral, so models designed to represent them cannot remain static. Integrating temporal factors into this model engenders further complexity.

This dissertation evaluates the use …

On Dedekind’S “Über Die Permutationen Des Körpers Aller Algebraischen Zahlen", Joseph Jp Arsenault Jr

Electronic Theses and Dissertations

We provide an analytic read-through of Richard Dedekind's 1901 article “Über die Permutationen des Körpers aller algebraischen Zahlen," describing the principal results concerning infinite Galois theory from both Dedekind's point of view and a modern perspective, noting an apparently uncorrected error in the supplement to the article in the Collected Works. As there is no published English-language translation of the article, we provide an annotated original translation.

Method Development For Vitamin C Quantification In Two Complex Matrices, Hannah D. Hutt

Electronic Theses and Dissertations

The following liquid chromatographic (LC) method developments and applied research studies were done using two complex food matrices, potatoes and elderberries, which are common to the state of Maine. Potatoes are Maine’s largest agricultural crop, a staple food in most U.S. households, and are, from an analytical standpoint, considered a complex matrix due to the high starch content that can be difficult to remove without degrading or removing nutrients in the process. Elderberries are an emerging crop in the U.S. because of their antioxidant and anti-viral properties and are found growing wild, throughout Maine. Elderberries are also considered a complex …

Reconstructing Late Holocene Hydrographic Variability Of The Gulf Of Maine, Nina Millicent Whitney

Electronic Theses and Dissertations

I present an annually resolved reconstruction of seawater temperatures in the

western North Atlantic from 1695-1915. This paleoclimate record was constructed

using oxygen isotopes measured in precisely dated Arctica islandica shells collected

off of Seguin Island in the western Gulf of Maine. The temperature reconstruction

was derived from this oxygen isotope time series using a modern d¹⁸O_w-salinity

mixing line developed for coastal waters in the Gulf of Maine from water samples

collected over the last decade. The d¹⁸O_w and salinity composition of these water

samples indicate that coastal surface waters consist of a …

Detection Of Iron (Iii) Using Magnetic Nanoparticles, Kaiya Hansen

Electronic Theses and Dissertations

The goal of this work was to develop an iron (III) sensor which can be mounted on buoys and gliders and automatically measure iron (III) in the ocean. The method investigated in this thesis was based on anchoring the iron (III) chelator desferrioxamine B (DFB) to magnetic particles. DFB selectively binds iron (III), resulting in a complex which produces a broad absorbance band at 430 nm. This band can be measured via UV-Vis spectroscopy (UV-Vis). However, measuring oceanic iron (III) directly in solution is difficult because the concentrations can be very low, sometimes less than 1 nM. This problem could …

Temperature As A Proxy To Study The Flow Of Water Within Two Maine Streambeds, Jarrod D. Cicha

Electronic Theses and Dissertations

Heat transport studies often focus on calculating an average direction and magnitude of groundwater flow within the streambed for long (3 days – 1 week) periods of time. Short-term changes in flow magnitude and/or direction within the streambed caused by near stream groundwater pumping and storms are not represented by these long term averaging methods. Temperature profiles collected in B Stream (Houlton, Maine) and the Stillwater River (Orono, Maine) were used to calibrate a one-dimensional heat transport model and quantify short-term hydraulic events in vertical groundwater velocity within streambeds. Temperature profiles were collected during the summer of 2014 with iButton …

Topographic Signatures Of Geodynamics, Samuel G. Roy

Electronic Theses and Dissertations

The surface of the Earth retains an imperfect memory of the diverse geodynamic, climatic, and surface transport processes that cooperatively drive the evolution of Earth. In this thesis I explore the potential of using topographic analysis and landscape evolution models to unlock past and/or present evidence for geodynamic activity. I explore the potential isolated effects of geodynamics on landscape evolution, particularly focusing on two byproducts of tectonic strain: rock displacement and damage. Field evidence supports a strong correlation between rock damage and erodibility, and a numerical sensitivity analysis supports the hypothesis that an order of magnitude weakening in rock, well …

Individual Tree Measurements From Three-Dimensional Point Clouds, Elias Ayrey

Electronic Theses and Dissertations

This study develops and tests novel methodologies for measuring the attributes of individual trees from three-dimensional point clouds generated from an aerial platform. Recently, advancements in technology have allowed for the acquisition of very high resolution three-dimensional point clouds that can be used to map the forest in a virtual environment. These point clouds can be interpreted to produce valuable forest attributes across entire landscapes with minimal field labor, which can then aid forest managers in their planning and decision making.

Biometrics derived from point clouds are often generated on a plot level, with estimates spanning many meters (rather than …

Synthesis Of Phenothiazinium Derivatives, Selorm J. Fanah

Electronic Theses and Dissertations

Photodynamic therapy (PDT) employs photosensitizing drugs for treating cancer. Once introduced into the body and localized in tumor cells, these photosensitizers are irradiated with light to produce active singlet oxygen radicals which kill cancer cells. The current drugs used in PDT have low quantum yield and always require a high energy radiation (normally laser). There is always a need for more effective drugs that have a high quantum yield and can be activated by visible light, in order to eliminate side effects caused by laser radiations.

In this work we synthesized derivatives of phenothiazine and phenothiazinium chromophores from the commercially …

Candida Albicans Hyphal Mannan Is Structurally Distinct From Yeast Mannan, Francis Kwofie

Electronic Theses and Dissertations

C. albicans is a polymorphic fungal pathogen which has the ability to shift from yeast to hyphae. C. albicans cell wall is composed of glucan, chitin, mannoprotein and mannan. It is not possible, using standard extraction methods, to isolate mannan from C. albicans hyphae. To isolate hyphal mannan, we developed a simplified alkali extraction method. Using this method it was determined that hyphal mannan has a much lower molecular weight, a smaller polymer distribution and altered conformation structure when compared to yeast mannan. The hyphal mannan was found to contain little to no acid-labile portion with only α-Man-PO₄ groups …

Comparison Of Two Parameter Estimation Techniques For Stochastic Models, Thomas C. Robacker

Electronic Theses and Dissertations

Parameter estimation techniques have been successfully and extensively applied to deterministic models based on ordinary differential equations but are in early development for stochastic models. In this thesis, we first investigate using parameter estimation techniques for a deterministic model to approximate parameters in a corresponding stochastic model. The basis behind this approach lies in the Kurtz limit theorem which implies that for large populations, the realizations of the stochastic model converge to the deterministic model. We show for two example models that this approach often fails to estimate parameters well when the population size is small. We then develop a …

The Pc-Tree Algorithm, Kuratowski Subdivisions, And The Torus., Charles J. Suer

Electronic Theses and Dissertations

The PC-Tree algorithm of Shih and Hsu (1999) is a practical linear-time planarity algorithm that provides a plane embedding of the given graph if it is planar and a Kuratowski subdivision otherwise. Remarkably, there is no known linear-time algorithm for embedding graphs on the torus. We extend the PC-Tree algorithm to a practical, linear-time toroidality test for K3;3-free graphs called the PCK-Tree algorithm. We also prove that it is NP-complete to decide whether the edges of a graph can be covered with two Kuratowski subdivisions. This greatly reduces the possibility of a polynomial-time toroidality testing algorithm based solely on edge-coverings …

Application Of Surface Chemistry At The Interface Of Mesoporous Tio2 Films For Stable And High Efficiency Dye-Sensitized Solar Cells., Tulashi Luitel

Electronic Theses and Dissertations

Solar energy is widely believed to be the most promising renewable energy source to fulfill the ever-increasing energy demand from human society now and into the future. Dye-sensitized solar cells (DSSCs) have been explored as a potentially low-cost alternative to silicon solar cell technology due to their lower fabrication costs compared to crystalline semiconductor photovoltaics. However, the optimized efficiency for DSSCs has not been achieved yet, and the chemical stability between dye and semiconductor has also not been addressed completely. In this research, we applied the following four main strategies to prepare photoanodes used in DSSCs with the aim of …

Order Automorphisms On The Lattice Of Residuated Maps Of Some Special Nondistributive Lattices., Erika D. Foreman

Electronic Theses and Dissertations

The residuated maps from a lattice L to itself form their own lattice, which we denote Res(L). In this dissertation, we explore the order automorphisms on the lattice Res(L) where L is a finite nondistributive lattice. It is known that left and right composition of f ∈ Res(L) with automorphisms of L yields an order automorphism of Res(L). It begs the question, then, if all order automorphisms of Res(L) can be classified as such.

Methodology Study Of N-Deacetylation Of 4-Acetamido-Perfluoroalkylbenzenesulfonimide, Grace Abban

Electronic Theses and Dissertations

In order to improve the synthetic route for diazonium perfluoroalkyl benzenesulfonylimide (PFSI) zwitterionic monomers, N-deacetylation of the coupling product was proposed to replace the reduction of aromatic amine intermediates. A series of hydrolysis methods, such as acid and base catalyzed refluxing, were explored for the N-deacetylation to obtain the PFSI aromatic amine. Factors such as temperature, concentration of acid/base and the time needed for the reaction to take place were investigated in an attempt to optimize the reaction condition. The basic hydrolysis was preferred since it was expected to carry out the N-deacetylation and debromination in one …

Linkage Analysis And Compositional Studies Of Β-Glucan From Saccharomyces Cerevisiae And Compositional Studies Of Mannan From Candida Albicans, Clara Arthur

Electronic Theses and Dissertations

The efficacy of a novel carbohydrate extraction procedure was investigated with methylation analysis and alditol acetate method by Gas Chromatography-Mass Spectrometry. A published extraction procedure for β-glucans was compared to one developed in house. Both procedures gave a dominant glucose peak in the Gas chromatogram indicative of successful β-glucan isolation. Further linkage studies showed four linkage positions for β-glucans isolated with the published method; terminal, 1,3-linkage, 1,6-linkage and 1,3,6-linkage, while β-glucans isolated using the new method showed six linkage positions; terminal, 1,3-linkage, 1,6-linkage, 1,4-linkage, 1,2,3-linkage and 1,3,6-linkage. Diminishing β-glucan linkage peaks in the chromatogram for the published method indicated structure …

Phosphinimine Zinc Complexes And Neutral Phosphinimines For Ring Opening Polymerization Of Lactides., Rajesh Thapa

Electronic Theses and Dissertations

Achiral arenesulfonates ligands having a (NNN) or (NNO) side arm have been developed (Chapter 2) and their respective zinc ethyl complexes, NNNZnEt 3.2 and NNOZnEt 3.3, have been synthesized and characterized using spectroscopic methods (Chapter 3). NNNZnEt as well as NNOZnEt complexes are stable under nitrogen atmosphere. In the NNOZnEt 3.3 complex the protons associated with the pendant (dimethylamino)ethyl arm are broad indicating that a fluxional process is operative, most likely dissociation of the (dimethylamino)ethyl arm at 25 °C in CD2Cl2. The fluxional behavior present in the 1H NMR spectrum of 3.2 could be arrested by cooling the CD2Cl2 solution …