Physical Sciences and Mathematics Commons^™

Stability And Differential Privacy Of Stochastic Gradient Methods, Zhenhuan Yang

Legacy Theses & Dissertations (2009 - 2024)

Recently there are a considerable amount of work devoted to the study of the algorithmic stability as well as differential privacy (DP) for stochastic gradient methods (SGM). However, most of the existing work focus on the empirical risk minimization (ERM) and the population risk minimization problems. In this paper, we study two types of optimization problems that enjoy wide applications in modern machine learning, namely the minimax problem and the pairwise learning problem.

Data Collection And Machine Learning Methods For Automated Pedestrian Facility Detection And Mensuration, Joseph Bailey Luttrell Iv

Dissertations

Large-scale collection of pedestrian facility (crosswalks, sidewalks, etc.) presence data is vital to the success of efforts to improve pedestrian facility management, safety analysis, and road network planning. However, this kind of data is typically not available on a large scale due to the high labor and time costs that are the result of relying on manual data collection methods. Therefore, methods for automating this process using techniques such as machine learning are currently being explored by researchers. In our work, we mainly focus on machine learning methods for the detection of crosswalks and sidewalks from both aerial and street-view …

Glaciernet2: A Hybrid Multi-Model Learning Architecture For Alpine Glacier Mapping, Zhiyuan Xie, Umesh K. Haritashya, Vijayan K. Asari, Michael P. Bishop, Jeffrey S. Kargel, Theus Aspiras

Electrical and Computer Engineering Faculty Publications

In recent decades, climate change has significantly affected glacier dynamics, resulting in mass loss and an increased risk of glacier-related hazards including supraglacial and proglacial lake development, as well as catastrophic outburst flooding. Rapidly changing conditions dictate the need for continuous and detailed ob-servations and analysis of climate-glacier dynamics. Thematic and quantitative information regarding glacier geometry is fundamental for understanding climate forcing and the sensitivity of glaciers to climate change, however, accurately mapping debris-cover glaciers (DCGs) is notoriously difficult based upon the use of spectral information and conventional machine-learning techniques. The objective of this research is to improve upon an …

Tess Discovery Of A Sub-Neptune Orbiting A Mid-M Dwarf Toi-2136, T. Gan, A. Soubkiou, S. X. Wang, Z. Benkhaldoun, S. Mao, É. Artigau, P. Fouqué, L. Arnold, S. Giacalone, C. A. Theissen, C. Aganze, A. Burgasser, K. A. Collins, A. Shporer, K. Barkaoui, M. Ghachoui, S. B. Howell, C. Lamman, O. D. S. Demangeon, A. Burdanov, C. Cadieux, J. Chouqar, K. I. Collins, N. J. Cook, L. Delrez, B.-O. Demory, R. Doyon, G. Dransfield, C. D. Dressing, E. Ducrot, J. Fan, L. Garcia, H. Gill, M. Gillon, C. L. Gnilka, Y. Gómez Maqueo Chew, M. N. Günther, C. E. Henze, C. X. Huang, E. Jehin, Eric L.N. Jensen, Z. Lin, N. Manset, J. Mccormac, C. A. Murray, P. Niraula, P. P. Pedersen, F. J. Pozuelos, D. Queloz, B. V. Rackham, A. B. Savel, N. Schanche, R. P. Schwarz, D. Sebastian, S. Thompson, M. Timmermans, A. H. M. J. Triaud, M. Vezie, R. D. Wells, J. De Wit, G. R. Ricker, R. Vanderspek, D. W. Latham, S. Seager, J. N. Winn, J. M. Jenkins

Physics & Astronomy Faculty Works

We present the discovery of TOI-2136 b, a sub-Neptune planet transiting a nearby M4.5V-type star every 7.85 d, identified through photometric measurements from the Transiting Exoplanet Survey Satellite (TESS) mission. The host star is located 33 pc away with a radius of R* = 0.34 ± 0.02 R_⊙, a mass of 0.34 ± 0.02 M_⊙, and an effective temperature of 3342 ± 100 K. We estimate its stellar rotation period to be 75 ± 5 d based on archival long-term photometry. We confirm and characterize the planet based on a series of ground-based multiwavelength …

The Tess Grand Unified Hot Jupiter Survey. I. Ten Tess Planets, S. W. Yee, J. N. Winn, J. D. Hartman, J. E. Rodriguez, G. Zhou, S. N. Quinn, D. W. Latham, A. Bieryla, K. A. Collins, B. C. Addison, I. Angelo, K. Barkaoui, P. Benni, A. W. Boyle, R. Brahm, R. P. Butler, D. R. Ciardi, K. I. Collins, D. M. Conti, J. D. Crane, F. Dai, C. D. Dressing, J. D. Eastman, Z. Essack, R. Forés-Toribio, E. Furlan, T. Gan, S. Giacalone, H. Gill, E. Girardin, T. Henning, C. E. Henze, M. J. Hobson, J. Horner, A. W. Howard, S. B. Howell, C. X. Huang, H. Isaacson, J. M. Jenkins, Eric L.N. Jensen, A. Jordán, S. R. Kane, J. F. Kielkopf, S. Lasota, A. M. Levine, J. Lubin, A. W. Mann, B. Massey, K. K. Mcleod, M. W. Mengel, J. A. Muñoz, F. Murgas, E. Palle, P. Plavchan, A. Popowicz, D. J. Radford, G. R. Ricker, P. Rowden, B. S. Safonov, A. B. Savel, R. P. Schwarz, S. Seager, R. Sefako, A. Shporer, G. Srdoc, I. S. Strakhov, J. K. Teske, C. G. Tinney, D. Tyler, R. A. Wittenmyer, H. Zhang, C. Ziegler

Physics & Astronomy Faculty Works

Hot Jupiters—short-period giant planets—were the first extrasolar planets to be discovered, but many questions about their origin remain. NASA's Transiting Exoplanet Survey Satellite (TESS), an all-sky search for transiting planets, presents an opportunity to address these questions by constructing a uniform sample of hot Jupiters for demographic study through new detections and unifying the work of previous ground-based transit surveys. As the first results of an effort to build this large sample of planets, we report here the discovery of 10 new hot Jupiters (TOI-2193A b, TOI-2207b, TOI-2236b, TOI-2421b, TOI-2567b, TOI-2570b, TOI-3331b, TOI-3540A b, TOI-3693b, TOI-4137b). All of the planets …

Chromosome Number Evolution, Phylogeography, And The Effects Of Climate Change On Species Distributions In Polyploid Plant Systems, Courtney H. Babin

University of New Orleans Theses and Dissertations

Polyploidy, a term used to describe organisms with cells having more than two paired sets of chromosomes, is a significant driver of diversification among land plants. Over a century of research has advanced our understanding of polyploidization in some taxa, but polyploid organisms remain understudied. In this dissertation, I investigate chromosome number evolution, phylogeographic structure, genetic differentiation, and the effects of climate change on ploidy level distribution using polyploid plant systems. In the first chapter, I inferred a molecular phylogeny of Allium, an economically important genus that includes cultivated crops and ornamentals, to investigate evolutionary transitions in chromosome number …

Facies Analysis Of Terrebonne Basin Using Vibracores And Chirp Seismic Data, Joseph M. Hankerson

University of New Orleans Theses and Dissertations

This study was conducted in upper and lower Madison Bay as well as Lake Boudreaux in Terrebonne basin located in southcentral Louisiana. This region is part of the recently abandoned Lafourche delta complex (0.6-0.8 kyr). Much of coastal Louisiana is comprised of formerly active delta complexes of the Mississippi River that have undergone subsequent reworking. As more restoration actions are being considered to combat land loss in coastal Louisiana, exploring the framework of a recently abandoned delta complex could aid in these plans. Utilizing core descriptions and CHIRP seismic data, facies analysis was performed to produce cross sections that display …

An Economical And Repeatable Method For Mapping Shade Cast On Water Channels, Eric M. Nielsen

Institute for Natural Resources Publications

The motivation of this work is to provide insights toward determining a viable strategy for statewide monitoring of riparian vegetation condition, with particular focus on developing a repeatable, costeffective method for assessment of progress toward achieving temperature-based water quality standards mandated by the federal Clean Water Act. A reliable monitoring strategy could in turn support a datadriven prioritization and assessment framework to increase the efficiency, effectiveness and accountability of riparian restoration efforts. In this project we developed and tested a method for mapping shade cast on water channels by riparian vegetation using optical imagery sources that are affordable and regularly …

Conservation Conflict: Rare Plant Conservation And Energy Development And Potential In The Colorado Plateau, Joshua Carrell

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Colorado Plateau provides numerous sources of energy, particularly natural oil and gas. This energy potential is being actively extracted for consumption on both public and private lands. Elements of biodiversity (e.g., listed and sensitive plant and animal species) are distributed among all land tenures, yet the laws protecting them can vary depending if they occur on public, private, or tribal land. Therefore, it is necessary to understand the geographic ranges of threatened, endangered, and sensitive species and their relationship to land ownership to preserve habitat and conserve species populations. I developed species distribution models (SDMs) to examine the predicted …

Assessment Of Historical Climate Variability In Maine With Implications For Future Agricultural Productivity And Adaptation, Carly Frank

Electronic Theses and Dissertations

Climate change is a wicked problem with global impacts, one of which being the sustainability of the existing global food system. As temperatures and variability in precipitation are projected to increase, the challenges to agriculture are expected to intensify. This thesis examines the Maine historical climate record over the growing season, in combination with future projections, to assess how conditions have changed and will change with agricultural implications. In this analysis, relevant climatic variables are analyzed, and agriculture-significant measures are derived for Maine’s three climate divisions using four decades of daily and monthly gridded datasets. In addition, this thesis explores …

Effects Of Excessive Soil Phosphorus Accumulation On Loblolly Pine (Pinus Taeda L.) Seedlings, Hannah C. Bays

Electronic Theses and Dissertations

Many landowners in East Texas apply poultry litter to pastures as a source of nitrogen (N) for forage crops. After many years of repeated poultry litter application, soils can accumulate extremely high extractable phosphorus (P) concentrations, sometimes over 1000 mg kg^-1 of plant available P. Landowners report the conversion of these pastures to loblolly pine (Pinus taeda L.) plantations is often problematic, with poor seedling survival and abnormal tree growth. This study was conducted to assess the effects of excessive soil phosphorus on loblolly pine seedlings. An outdoor pot study was conducted using bare root seedlings and triple …

Social Media Analytics With Applications In Disaster Management And Covid-19 Events, Md Yasin Kabir

Doctoral Dissertations

"Social media such as Twitter offers a tremendous amount of data throughout an event or a disastrous situation. Leveraging social media data during a disaster is beneficial for effective and efficient disaster management. Information extraction, trend identification, and determining public reactions might help in the future disaster or even avert such an event. However, during a disaster situation, a robust system is required that can be deployed faster and process relevant information with satisfactory performance in real-time. This work outlines the research contributions toward developing such an effective system for disaster management, where it is paramount to develop automated machine-enabled …

Semiparametric Estimation With Clustered Right Censored Data Via Multivariate Gaussian Random Fields, Fathima Zahra Sainul Abdeen

Doctoral Dissertations

Consider a fixed number of clustered areas identified by their geographical coordinate that are monitored for the occurrences of an event such as pandemic, epidemic, migration to name a few. Data collected on units at all areas include time varying covariates and other environmental factors that may affect event occurrences. The event times in every area can be independent. They can also be correlated with correlation between two units induced by an unobservable frailty. In both cases, the collected data is considered pairwise to account for spatial correlation between all pair of areas. The pairwise right censored data is probit-transformed …

Quantifying And Predicting Drought Performance In Woody Semi-Arid Seedlings In South Texas: Implications For Enhancing Drought Resilience In Restoration, Zarek Contreras

Theses and Dissertations

Increasingly frequent and severe droughts in the Lower Rio Grande Valley National Wildlife Refuge have been observed to cause large variation in species-specific mortality patterns in young seedlings, spanning 6 – 43 % mortality within the first year. To understand the underlying mechanisms behind this, we subjected seedlings of five woody semi-arid species (Celtis pallida, Forestiera angustifolia, Sideroxylon celastrinum, Phaulothalmnus spinescens, and Zanthoxylum fagara) to a point-of-no-return drought experiment in order to (1) identify potential metrics capable of predicting species wilting and mortality responses, and (2) to understand the underlying mechanisms that correspond to species drought performance …

Fish Community Analysis Using Multidirectional Rov Video Surveys In The Northwestern Gulf Of Mexico, Keegan J. Angerer

Theses and Dissertations

In this study, ROV surveys with multidirectional video were used to analyze the fish communities associated with artificial reef patches in the Rio Grande Valley artificial reef 13.7 km off the coast of South Padre Island, TX. Nine configurations of reef patches consisting of varying combinations and densities of concrete pyramid and low-profile modules were surveyed. The highest species diversity was found at patches with large deployments of both pyramids and low-profile modules. Total Red Snapper Lutjanus campechanus abundance did not differ between configurations, but the highest abundances of juvenile Red Snapper were found at configurations with one pyramid and …

Assessment Of Nitrogen-Based Fertilizer Transport And Microbial Activities In Sandy Soil Profiles In South Texas, Gladys De La Rosa

Theses and Dissertations

Conventional farming is a common practice in Lower Rio Grande Valley (LRGV) and the application of nitrogen fertilizer is essential for plant growth and support. However, managing the rate of nitrogen that is applied can benefit farmers financially and reduce nitrate leaching that can have an adverse effect on the local environment and aquatic systems, e.g., rivers and estuaries. Sandy soils are more vulnerable to water infiltration due to the large proportion of macropores. This study aims to (i) assess how nitrate from a variety of fertilizers (i.e., synthetic and organic) distributes on the top 60 cm layer of a …

Tree Ring Reconstructions Of Streamflow For The Lower Rio Grande Valley Of Texas, Adedolapo Mutiyat Adeyanju

Theses and Dissertations

The Rio Grande River is a major water source for people living within the USA-Mexico border. The Rio Grande River has its headwaters in the San Juan Mountains in Colorado and the Sierra Madre Occidental in Mexico before flowing into Texas through El-Paso. The water supply issues facing the Lower Rio Grande Basin (LRGB) are extremely complex from international restrictions to severe climate change. The river shares its flow between the U.S.A and Mexico based on the provisions of the 1944 treaty between the U.S.A and Mexico. The LRGB flow is regulated by releases from Falcon and Amistad Reservoirs managed …

Mathematics Teachers’ Working With Cooperative Learning, Jaime Gomez

Theses and Dissertations

Teaching styles vary greatly amongst educators. One being extensively researched and highly discussed is the method of cooperative learning. Although many studies have shown the benefits of incorporating cooperative learning into classrooms, it has not been a widely used method of teaching in high school mathematics classrooms. This study explores some of the efforts that teachers, who utilize cooperative learning in their classrooms, make to implement cooperative learning lessons successfully. Furthermore, this study also explores the challenges these teachers have encountered when using cooperative learning. Data was collected qualitatively by interviews and surveys from six in-service high …

Red Drum (Sciaenops Ocellatus) Trophic Web Reconstruction Using Stable Isotopes In Two Systems In The Northwestern Gulf Of Mexico, Elizabeth Mogus Garcia

Theses and Dissertations

Estuaries act as nurseries for many important fishes, including predators like Red Drum (Sciaenops ocellatus). Using gut content and stable isotope analyses to better understand juvenile S. ocellatus’ diet and role within the trophic web, a full year of data was collected on a quarterly basis to illustrate a change in diet based on resource availability at two study sites and for two non-overlapping S. ocellatus sizes. Panopeidae and Penaeidae were the most abundant prey items found in S. ocellatus stomachs for both sizes, sites, and four quarters representing over 50% of the diet. Stable isotope analyses …

Traveling Wave Solutions For The Negative Order Hierarchy Of The D-Akns Equations, Brayton Isaac Wario

Theses and Dissertations

In the thesis work, based on the D-AKNS spectral problem, we study the negative-order D-AKNS (ND-AKNS) hierarchy. In particular, the first ND-AKNS equation is derived from the negative-order D-AKNS hierarchy, which is proved integrable in the sense of Lax pair. Furthermore, we discuss the traveling wave solutions to the ND-AKNS Equation, including possible soliton solutions.

A Real-Time Activity Recognition In A Congested Wireless Environment, Israel Oludayo Elujide

Computer Science and Engineering Dissertations

ABSTRACT: This dissertation reports on how to achieve real-time activity recognition in a congested wireless environment. Recently, human activity recognition with WiFi has been the focus of many researchers due to the limitations of legacy approaches like video cameras and sensors. Users have concerns with privacy when it comes to video activity recognition. Likewise, activity recognition sensors can be expensive, obtrusive, and inconvenient to be worn for an extended period of time. The urgency for implementing contactless activity recognition has also been accelerated due to changes in society and social interaction because of the COVID-19 pandemic. Many public facilities like …

C -Axis Transport In Ute2: Evidence Of Three-Dimensional Conductivity Component, Yun Suk Eo, Shouzheng Liu, Shanta R. Saha, Hyunsoo Kim, Sheng Ran, Jarryd A. Horn, Halyna Hodovanets, John Collini, Tristin Metz, Wesley T. Fuhrman, Andriy H. Nevidomskyy, Jonathan D. Denlinger, Nicholas P. Butch, Michael S. Fuhrer

Physics Faculty Research & Creative Works

We study the temperature dependence of electrical resistivity for currents directed along all crystallographic axes of the spin-triplet superconductor UTe2. We focus particularly on an accurate determination of the resistivity along the c axis (ρc) by using a generalized Montgomery technique that allows extraction of crystallographic resistivity components from a single sample. In contrast to expectations from the observed highly anisotropic band structure, our measurement of the absolute values of resistivities in all current directions reveals a surprisingly nearly isotropic transport behavior at temperatures above Kondo coherence, with ρc∼ρb∼2ρa, that evolves to reveal qualitatively distinct behaviors on cooling. The temperature …

Two-Path Interference In Resonance-Enhanced Few-Photon Ionization Of Li Atoms, B. P. Acharya, S. Dubey, K. L. Romans, A. H.N.C. De Silva, K. Foster, O. Russ, K. Bartschat, N. Douguet, Daniel Fischer

Physics Faculty Research & Creative Works

We investigate the resonance-enhanced few-photon ionization of atomic lithium by linearly polarized light whose frequency is tuned near the 2s-2p transition. Considering the direction of light polarization orthogonal to the quantization axis, the process can be viewed as an atomic "double-slit experiment "where the 2p states with magnetic quantum numbers mℓ=±1 act as the slits. In our experiment, we can virtually close one of the two slits by preparing lithium in one of the two circularly polarized 2p states before subjecting it to the ionizing radiation. This allows us to extract the interference term between the two pathways and obtain …

Self-Intercalation Tunable Interlayer Exchange Coupling In A Synthetic Van Der Waals Antiferromagnet, Xiaoqian Zhang, Wenqing Liu, Wei Niu, Qiangsheng Lu, Wei Wang, Ali Sarikhani, Xiaohua Wu, Chunhui Zhu, Jiabao Sun, Mitchel Vaninger, Paul F. Miceli, Jianqi Li, David J. Singh, Yew San Hor

Physics Faculty Research & Creative Works

One of the most promising avenues in 2D materials research is the synthesis of antiferromagnets employing 2D van der Waals (vdW) magnets. However, it has proven challenging, due in part to the complicated fabrication process and undesired adsorbates as well as the significantly deteriorated ferromagnetism at atomic layers. Here, the engineering of the antiferromagnetic (AFM) interlayer exchange coupling between atomically thin yet ferromagnetic CrTe2 layers in an ultra-high vacuum-free 2D magnetic crystal, Cr5Te8 is reported. By self-introducing interstitial Cr atoms in the vdW gaps, the emergent AFM ordering and the resultant giant magnetoresistance effect are induced. A large negative magnetoresistance …

"Design For Co-Design" In A Computer Science Curriculum Research-Practice Partnership, Victor R. Lee, Jody Clarke-Midura, Jessica F. Shumway, Mimi Recker

Publications

This paper reports on a study of the dynamics of a Research-Practice Partnership (RPP) oriented around design, specifically the co-design model. The RPP is focused on supporting elementary school computer science (CS) instruction by involving paraprofessional educators and teachers in curricular co-design. A problem of practice addressed is that few elementary educators have backgrounds in teaching CS and have limited available instructional time and budget for CS. The co-design strategy entailed highlighting CS concepts in the mathematics curriculum during classroom instruction and designing computer lab lessons that explored related ideas through programming. Analyses focused on tensions within RPP interaction dynamics …

Storing Water For The Environment: Operating Reservoirs To Improve California’S Freshwater Ecosystems, Sarah Null, Jeffrey Mount, Brian Gray, Kristen Dybala, Gokce Sencan, Anna Sturrock, Barton Thompson, Harrison Zeff

Watershed Sciences Faculty Publications

California’s freshwater ecosystems—its lakes, rivers, floodplains, meadows, natural and managed wetlands, and estuaries—are a vital part of the state’s natural infrastructure. These ecosystems provide numerous benefits, including water supply, hydropower, flood control, fisheries, recreation, and cultural and aesthetic value. They are also home to the nation’s most diverse array of plant and animal communities, with numerous freshwater species found only in California (Jensen et al. 1993; Grantham et al. 2017).

Optical And Computational Methods For Detection And Quantification Of Protein-Protein Interactions Using Single-Molecule Localization Microscopy, David James Schodt

Physics & Astronomy ETDs

Interactions between proteins residing on or near the membranes of biological cells trigger many of the signaling cascades that facilitate the transmission of information between the exterior and the interior of the cell. Normal function of these protein-protein interactions (PPIs) is required for the healthy functioning of complex single- and multi-cellular organisms. Abnormalities involving these interactions are implicated in several diseases, such as the progression and treatment resistance of many forms of cancer. Understanding both the normal and abnormal behaviors of these interactions is necessary to improve our understanding of such diseases, which in turn can drive drug development for …

Survivor Bond Models For Securitizing Longevity Risk, Priscilla Mansah Codjoe

Doctoral Dissertations

"Longevity risk is the risk that a reference population’s mortality rates deviate from what is projected from prior life tables. This is due to discoveries in biological sciences, improved public health measures, and nutrition, which have dramatically increased life expectancy. Longevity risk raises life insurers’ liability, increasing product costs and reserves. Securitization through longevity derivatives is a way of dealing with this risk.

To enhance the pricing of life contingent products, we present an additive type mortality model in the style of the Lee-Carter. This model incorporates policyholder covariates. By using counting processes and martingale machinery, we obtain close form …

Elegance Or Alchemy? An International Cross-Case Analysis Of Faculty And Graduate Student Perceptions Of Mathematical Proofs, Brooke Nicole Denney

Masters Theses

Artist Marcel Duchamp once said, ``The painter is a medium who doesn’t realize what he is doing. No translation can express the mystery of sensibility, a word, still unreliable, which is nonetheless the basis of painting or poetry, like a kind of alchemy" (Moffitt, 2012). Just as there is a puzzling aspect of creating art or writing poetry, the aesthetic quality of mathematical proofs is a mysterious and ill-defined concept. Like many other subjective terms, it can be difficult to reach a consensus on what elegance means in a mathematical context. In this thesis, I try to better understand faculty …

Kinematic And Vorticity Analysis Of The Slide Lake And Homestake Shear Zones, Central Colorado, Carsen T. Adams

Masters Theses

Kinematic and quantitative vorticity analysis of the Homestake shear zone (HSZ) and the Slide Lake shear zone (SLSZ) in central Colorado provide further insight into crustal processes that controlled deformation within the Colorado Mineral Belt (CMB) shear zone system throughout the Proterozoic. Evaluating vorticity, that is, the relative contributions of pure to simple shear in sheared rocks, is crucial to understanding lithospheric tectonic evolution and allows for kinematic modeling of shear zone development at a variety of scales. Moreover, novel vorticity analyses involve determining the orientation of the vorticity vector and vorticity normal surface which can give insight into shear …