Physical Sciences and Mathematics Commons^™

2019 Nebraska Water Leaders Academy Final Report, M.E. Burbach, R.M. Joeckel, G.S. Matkin

Conservation and Survey Division

No abstract provided.

Correlating The Plant Height Of Wheat With Above-Ground Biomass And Crop Yield Using Drone Imagery And Crop Surface Model, A Case Study From Nepal, U. S. Panday, Nawaraj Shrestha, S. Maharjan, A. K. Pratihast, Shahnawaz, K. L. Shrestha, J. Aryal

Conservation and Survey Division

No abstract provided.

Experimental And Numerical Investigations Of Granular Dynamics In Microgravity, Stephanie Jarmak

Electronic Theses and Dissertations, 2020-2023

During the first stages of planet formation small particles (~0.1 – 1 µm) in the protoplanetary disk collide at low relative velocities (less than 1 m/s) and tend to aggregate into cm-size "pebbles" through a combination of electrostatic interactions and gravitational streaming instabilities. Particles in this size regime also compose a layer of regolith on small, airless bodies that evolves under conditions very different than those on Earth. Characterizing the response of regolith to low-energy impacts in a microgravity environment is therefore critical to our understanding of the processes that lead to the formation of these objects and our ability …

Multi-Parameter Optical Metrology: Quantum And Classical, Walker Larson

Electronic Theses and Dissertations, 2020-2023

The insights offered by quantum mechanics to the field of optical metrology are many-fold, with non-classical states of light themselves used to make sensors that surpass the sensitivity of sensors using classical states of light. Unfortunately, this advantage, referred to often as "super-sensitivity" is notoriously fragile, and even the slightest experimental imperfections may greatly reduce the efficacy of the non-classical sensors, sometimes completely obviating their advantage. In my thesis I have shown that the performance of an otherwise ideal two-photon interferometer, which exploits entanglement between photons to make super-sensitive measurements of phase, is crippled by the slightest introduction of decoherence …

Design Of Ternary Operations Utilizing Flow-Based Computing, James Pyrich

Electronic Theses and Dissertations, 2020-2023

The development of algorithms and circuit designs that exploit devices that have the ability to persist multiple values will lead to alternative technologies to overcome the issues caused by the end of Dennard scaling and slowing of Moore's Law. Flow-based designs have been used to develop binary adders and multipliers. Data stored on non-volatile memristors are used to direct the flow of current through nanowires arranged in a crossbar. The algorithmic design of the flow-based crossbar is fast, compact, and efficient. In this paper, we seek to automate the discovery of flow-based designs of ternary circuits utilizing memristive crossbars.

Fluorescence Microscopy With Tailored Illumination Light, Jialei Tang

Electronic Theses and Dissertations, 2020-2023

Fluorescence microscopy has long been a valuable tool for biological and medical imaging. Control of optical parameters such as the amplitude, phase, polarization and propagation angle of light gives fluorescence imaging great capabilities ranging from single molecule imaging to long-term observation of living organisms. While numerous fluorescence imaging techniques have been developed over the past decades, there is always an inevitable tradeoff among the spatial resolution, imaging speed, contrast, photodamage and the total cost when it comes to choose the appropriate microscope. A main goal of my dissertation research is to develop state-of-the-art microscope systems that exhibit unprecedented performance in …

Explore And Design Novel Structures For More Efficient And Better Deep Convolutional Neural Networks, Min Wang

Electronic Theses and Dissertations, 2020-2023

Deep Convolutional Neural Networks have achieved remarkable performance on visual recognition problems, and have been extensively adopted in real-world applications, such as Apple's Face ID security system, autonomous driving cars, and automatic image tagging in online album services. One major concern in the development of CNNs is that their computational complexity grows along with the increase in their accuracy. Therefore, there is a continuous demand to find the right balance between accuracy and complexity in the design of CNN models. This dissertation focuses on designing various novel structures to enhance the performance of CNNs and their efficiency. Our efforts fall …

Equivariance And Invariance For Robust Unsupervised And Semi-Supervised Learning, Liheng Zhang

Electronic Theses and Dissertations, 2020-2023

Although there is a great success of applying deep learning on a wide variety of tasks, it heavily relies on a large amount of labeled training data, which could be hard to obtain in many real scenarios. To address this problem, unsupervised and semi-supervised learning emerge to take advantage of the plenty of cheap unlabeled data to improve the model generalization. In this dissertation, we claim that equivariant and invariance are two critical criteria to approach robust unsupervised and semi-supervised learning. The idea is as follows: the features of a robust model ought to be sufficiently informative and equivariant to …

Differential Recurrent Neural Networks For Human Activity Recognition, Naifan Zhuang

Electronic Theses and Dissertations, 2020-2023

Human activity recognition has been an active research area in recent years. The difficulty of this problem lies in the complex dynamical motion patterns embedded through the sequential frames. The Long Short-Term Memory (LSTM) recurrent neural network is capable of processing complex sequential information since it utilizes special gating schemes for learning representations from long input sequences. It has the potential to model various time-series data, where the current hidden state has to be considered in the context of the past hidden states. Unfortunately, the conventional LSTMs do not consider the impact of spatio-temporal dynamics corresponding to the given salient …

Learning Transferable Representations For Visual Recognition, Yang Zhang

Electronic Theses and Dissertations, 2020-2023

In the last half-decade, a new renaissance of machine learning originates from the applications of convolutional neural networks to visual recognition tasks. It is believed that a combination of big curated data and novel deep learning techniques can lead to unprecedented results. However, the increasingly large training data is still a drop in the ocean compared with scenarios in the wild. In this literature, we focus on learning transferable representation in the neural networks to ensure the models stay robust, even given different data distributions. We present three exemplar topics in three chapters, respectively: zero-shot learning, domain adaptation, and generalizable …

Attosecond Transient Absorption Spectroscopy In The Water Window, Andrew Chew

Electronic Theses and Dissertations, 2020-2023

The push to study the atomic and molecular dynamics at ever smaller time scales has been the main driving force for developing laser systems with ever shorter pulse durations. Thus far, picosecond lasers and femtosecond lasers have been used with great success in femtochemistry to study molecular dynamics such as molecular rotation and vibration, which all occur in the tens to hundreds of femtosecond. To study electron dynamics however, which are on the order of attoseconds, one needs attosecond laser sources to be able to have the time resolution required to probe ultrafast electron dynamics such as AC Stark shifts, …

High Performance Micro-Scale Light Emitting Diode Display, Fangwang Gou

Electronic Theses and Dissertations, 2020-2023

Micro-scale light emitting diode (micro-LED) is a potentially disruptive display technology because of its outstanding features such as high dynamic range, good sunlight readability, long lifetime, low power consumption, and wide color gamut. To achieve full-color displays, three approaches are commonly used: 1) to assemble individual RGB micro-LED pixels from semiconductor wafers to the same driving backplane through pick-and-place approach, which is referred to as mass transfer process; 2) to utilize monochromatic blue micro-LED with a color conversion film to obtain a white source first, and then employ color filters to form RGB pixels, and 3) to use blue or …

A Nested Pcr Strategy For Recovering Highly Discriminatory Y-Str Dna Profiles From Trace Male Dna Samples, Anna Kimball

Electronic Theses and Dissertations, 2020-2023

DNA profiling is an effective method of identifying individuals in forensic casework. In sexual assault cases in particular, male donor DNA can be genotyped using Y chromosome short tandem repeat (Y-STR) analysis even in the presence of significant levels of female DNA. The recently released recommended national standard for sexual assault evidence collection from the victim is within 5 days after the sexual assault, with the probability of obtaining a male DNA profile diminishing significantly thereafter due to degradation and/or loss of sperm. The present study was designed to develop a method of obtaining a highly probative DNA profile with …

Tensor Network States: Optimizations And Applications In Quantum Many-Body Physics And Machine Learning, Justin Reyes

Electronic Theses and Dissertations, 2020-2023

Tensor network states are ubiquitous in the investigation of quantum many-body (QMB) physics. Their advantage over other state representations is evident from their reduction in the computational complexity required to obtain various quantities of interest, namely observables. Additionally, they provide a natural platform for investigating entanglement properties within a system. In this dissertation, we develop various novel algorithms and optimizations to tensor networks for the investigation of QMB systems, including classical and quantum circuits. Specifically, we study optimizations for the two-dimensional Ising model in a transverse field, we create an algorithm for the $k$-SAT problem, and we study the entanglement …

Heterogeneous Integrated Photonics For Nonlinear Frequency Conversion And Polarization Diversity, Tracy Sjaardema

Electronic Theses and Dissertations, 2020-2023

Silicon has proven to be one of the materials of choice for many integrated photonic applications. However, silicon photonics is limited by certain material shortcomings. Two shortcomings addressed in this work are zero second-order optical nonlinearity, and the lack of methods available to achieve broadband polarization diversity. Heterogeneous integrated solutions for these shortcomings of silicon photonics are presented in this work. First, nonlinear frequency conversion is demonstrated with thin-film lithium niobate on silicon substrates. The method for reaching the highest-achieved second-harmonic generation conversion efficiency, using active monitoring during periodic poling, is discussed. Additionally, a cascaded approach for generating higher-order harmonics …

Algorithms For Inferring Multiple Microbial Networks, Sahar Tavakoli

Electronic Theses and Dissertations, 2020-2023

The interactions among the constituent members of a microbial community play a major role in determining the overall behavior of the community and the abundance levels of its members. These interactions can be modeled using a network whose nodes represent microbial taxa and edges represent pairwise interactions. A microbial network is a weighted graph that is constructed from a sample-taxa count matrix and can be used to model co-occurrences and/or interactions of the constituent members of a microbial community. The nodes in this graph represent microbial taxa and the edges represent pairwise associations amongst these taxa. A microbial network is …

Total Synthesis Of Natural Products From Oxidative Dearomatization, Nameer Ezzat

Electronic Theses and Dissertations, 2020-2023

The goal of our research is to prepare natural products and related core structures through oxidative dearomatization. The development of a stereoselective iron (III)-mediated intramolecular cascade dearomatization of phenol allowed access to various spirocyclohexadienones and tropons in one step using potassium ferricyanide via single electron transfer (SET). Using this oxidative dearomatization reaction, the thesis focuses on three main parts. The first part is the synthetic efforts toward total synthesis of Harringtonolide. The second part focused on the synthesis of spiro[4.5]decane, a core structure in multiple natural products. The spiro compounds were prepared from ortho hydroxyphenyl nitroalkanes using SET reaction with …

Infrastructure For Performance Monitoring And Analysis Of Systems And Applications, Ramin Izadpanah

Electronic Theses and Dissertations, 2020-2023

The growth of High Performance Computer (HPC) systems increases the complexity with respect to understanding resource utilization, system management, and performance issues. HPC performance monitoring tools need to collect information at both the application and system levels to yield a complete performance picture. Existing approaches limit the abilities of the users to do meaningful analysis on actionable timescale. Efficient infrastructures are required to support largescale systems performance data analysis for both run-time troubleshooting and post-run processing modes. In this dissertation, we present methods to fill these gaps in the infrastructure for HPC performance monitoring and analysis. First, we enhance the …

Improving Security Of Crypto Wallets In Blockchain Technologies, Hossein Rezaeighaleh

Electronic Theses and Dissertations, 2020-2023

A big challenge in blockchain and cryptocurrency is securing the private key from potential hackers. Nobody can rollback a transaction made with a stolen key once the network confirms it. The technical solution to protect private keys is the cryptocurrency wallet, software, hardware, or a combination to manage the keys. In this dissertation, we try to investigate the significant challenges in existing cryptocurrency wallets and propose innovative solutions. Firstly, almost all cryptocurrency wallets suffer from the lack of a secure and convenient backup and recovery process. We offer a new cryptographic scheme to securely back up a hardware wallet relying …

Emulsion Characterization Study For Improved Bilgewater Treatment And Management, Daniela Diaz Hernandez

Electronic Theses and Dissertations, 2020-2023

The need for proper management of bilgewater to meet discharge regulations (e.g., 15 ppm oil) has revealed the necessity to expand the current understanding of bilgewater emulsions. This study proposed to evaluate emulsion stability under various environmental conditions and to identify governing parameters for emulsion formation. The stabilizing properties of eight-commercial cleaners and two-neat surfactants were evaluated. In situ characterization techniques were used for monitoring emulsion stability. Additionally, a needle-type pH microsensor and fluorescence spectroscopy were used for analyzing mass transfer at the oil-water interface. Water quality of extracted bilgewater showed to highly vary between vessels (e.g., conductivity: 1.74 -- …

Discovery Of New Topological Quantum Materials By Photoemission, Md Mofazzel Hosen

Electronic Theses and Dissertations, 2020-2023

A topological insulator (TI) is a novel electronic state of quantum matter characterize by a bulk insulating bandgap and spin-polarized metallic surface states. Recently, the idea of topology protected surface states extended to semimetallic/metallic systems such as Dirac and Weyl semimetals. Unlike topological insulators where only surface states are interesting and topologically protected, Dirac and Weyl semimetals feature unusual bands in both on the surface and bulk. Dirac semimetals show photon-like linear band dispersion and exhibit a variety of exotic properties that include surface Fermi arc, large magnetoresistance, and high carrier mobility, etc. Recently, a new type of topological phase …

Urban Informality, Environmental Xenophobia, And Infrastructures Of Citizenship: The Political Lives Of Nicaraguan Migrants In The Informal Settlement Of La Carpio, Costa Rica, Nikolai Alexander Alvarado

Electronic Theses and Dissertations

This dissertation examines urban politics, environmental justice, and infrastructure from the vantage point of South-South migration. It focuses on the work of Nicaraguan migrants living in the informal settlement of La Carpio in San José, Costa Rica, as they negotiate rights in the form of urban services. Nicaraguans in La Carpio have organized politically since 1993 to self-install, demand, and negotiate services such as potable water and electricity. In the process, they successfully compel local authorities to allocate these services and grant them an implicit recognition of their right to remain and live a decent life, regardless of their status. …

Random Sampling, Lawrence Leemis

Arts & Sciences Book Chapters

Mathematical Statistics describes the mathematical underpinnings associated with the practice of statistics. The pre-requisite for this book is a calculus-based course in probability. Nearly 200 figures and dozens of Monte Carlo simulation experiments in R help develop the intuition behind the statistical methods. Real-world problems from a wide range of fields help the reader apply the statistical methods. Over 300 exercises are used to reinforce concepts and make this book appropriate for classroom use.

The table of contents for this book is given below.

1. Random Sampling 2. Point Estimation 3. Interval Estimation 4. Hypothesis Testing

Activation Of Nitrite And Carbon Dioxide By Cobalt Centered Redox Active Ligand Featuring A Hemilabile Pendant Amine, Douglas F. Baumgardner

WWU Graduate School Collection

Carbon dioxide (CO₂) and bioavailable nitrogen in the form of nitrates (NO₃^-) and nitrites (NO₂^-) are serious environmental pollutants. However, without economic incentives there is little interest in remediation of these pollutants outside of laboratory scale experiments. CO₂ can be converted to carbon monoxide (CO), a valuable building block in Fischer-Tropsch sourced fuel, and NO₃^- and NO₂^- can be converted to ammonia, another important chemical building block. However, both require effective, low-cost catalysts to be financially viable options. This thesis seeks to demonstrate the conversion of CO …

Land, Body, Liberation: An Ecofeminist Pedagogical Approach To Place-Based Education, Amy L. Fitkin

WWU Graduate School Collection

Within this project I applied an ecofeminism framework to the tangible practices of place-based education regarding issues of social justice-based sustainability efforts. In order to recognize the impact of identity-based privileges, I explore how place-based education promotes the development of problem-solving skills, critical-thinking techniques and building meaningful relationships within a community. These goals were achieved by shifting the white settler colonist understanding of human conquest and subjugation over land and bodies from an anthropocentric lens to an androcentric lens. In other words, illuminating the oppressive role the patriarchy has continued to play in exploiting natural "resources" and the bodies of …

Interdisciplinary Interspecies Pedagogies For Educating In The Anthropocene: Bringing Critical Animal Studies To Huxley College Of The Environment, Sarah R. (Sarah Rose) Olson

WWU Graduate School Collection

This report examines ENVS 499T Introduction to Critical Animal Studies: Theory, Agency, and Action, a 2-credit environmental humanities seminar designed as a M.Ed. in Environmental Education field project through Western Washington University’s (WWU) Huxley College of the Environment. ENVS 499T was created in response to a lack of critical animal studies course offering at WWU. The seminar was designed to provide WWU undergraduates with an opportunity to engage with interspecies ethical issues through an interdisciplinary lens. This report explores literature relevant to the design and implementation of this field project. It draws on scholars from critical animal studies and other …

Paleomagnetic And Structural Analysis Of Geothermal Drill Core From Akutan, Alaska, Molly Kathleen Johnson

WWU Graduate School Collection

Hot Springs Bay Valley (HSBV) geothermal resource area on Akutan Island, Alaska, has increased fluid output and temperature by almost a magnitude, between 1981 and 2012 (Bergfeld et al., 2014). These increases have been attributed to increased permeability along NW-SE trending faults that may have been activated during a seismic swarm in 1996. In 2010 two unoriented drill cores were collected in Hot Springs Bay geothermal resource area. In this study I reorient sections from one of the highly fractured cores with paleomagnetic data to test this model of geothermal reservoir evolution at Akutan. The core is composed of interlayered …

Plasmonic-Based Hybrid Nanomaterial: From Synthesis To Application, Maggie Wang

WWU Graduate School Collection

Gold nanoparticles, particularly gold nanorods, have been widely used as sensors and imaging agents due to their unique and tunable morphology-dependent properties and intriguing plasmonic resonance. However, the increasing need of new materials with enhanced properties and functionality led scientists to discover novel hybrid nanomaterials, which involves the formation of two or more components into one nanoplatform. Hence, gold nanorod-based hybrid nanomaterials exhibit simultaneous synergistic effects between the phenomenal plasmonic properties from gold nanorods and the intrinsic properties of the other constituents. The functionality of gold nanorod-based hybrid nanomaterials greatly increases due to its enhanced performance characteristics, which directly impacts …

Engineering Class A Sortases: Activity And Selectivity Of Hybrid And Ancestral Variants, Sarah Struyvenberg

WWU Graduate School Collection

Bacterial sortases are cysteine transpeptidases that anchor virulence factors to the surface of bacterial cells. Sortases are a powerful tool utilized for protein engineering that allow researchers to modify proteins at the protein level, not the DNA level. However, important limitations to utilization of sortases for engineering purposes exist; namely, SrtA from S. aureus is a relatively modest enzyme compared to other SrtA enzymes and is very specific for the LPXTG motif. Previous work from our collaborators and others revealed that sortases from different species can recognize alternative sequences and that activities can vary widely. We were curious about how …

Incorporating Characteristics Of Gene Drive Engineered Ae. Aegypti As Methods To Reduce Dengue And Zika Virus Into The Bayesian Network – Relative Risk Model, Using Ponce, Puerto Rico As A Case Study, Steven R. Eikenbary

WWU Graduate School Collection

This study proposes the use of the Bayesian network relative risk model (BN-RRM) to estimate the risk associated with the release of gene drives as vectors to control disease, using Ponce, Puerto Rico as a case study. Bayesian networks are an appropriate risk assessment tool for quantitatively and probabilistically examining complex systems involving multiple stressors acting on multiple endpoints in a wide variety of situations. The emerging field of synthetic biology has the capacity to drastically alter ecological systems with the use of gene drive engineered organisms as a method to alter population dynamics. The purpose of the release of …