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Articles 39601 - 39630 of 302421

Full-Text Articles in Physical Sciences and Mathematics

Deterring Non-Target Birds From Toxic Bait Sites For Wild Pigs, Nathan P. Snow, Joseph M. Halseth, Justin A. Foster, Michael J. Lavelle, Justin W. Fischer, Michael P. Glow, Ingrid A. Messer, Seth M. Cook, Kurt C. Vercauteren Dec 2021

Deterring Non-Target Birds From Toxic Bait Sites For Wild Pigs, Nathan P. Snow, Joseph M. Halseth, Justin A. Foster, Michael J. Lavelle, Justin W. Fischer, Michael P. Glow, Ingrid A. Messer, Seth M. Cook, Kurt C. Vercauteren

United States Department of Agriculture Wildlife Services: Staff Publications

Toxic baiting of wild pigs (Sus scrofa) is a potential new tool for population control and damage reduction in the US. Field trials testing a prototype toxic bait (HOGGONE 2 containing 5% sodium nitrite [SN]), though, revealed that wild pigs spilled small particles of toxic bait outside of bait stations which subsequently created hazards for non-target species that consumed those particles, primarily passerine birds. To deter non-target birds from consuming particles of spilled bait, we tested four deterrents at mock bait sites (i.e., baited with bird seed) in north-central Colorado, USA during April–May 2020. We found a programable, inflatable deterrent …


Towards A More Comprehensive Understanding Of Wild Pig (Sus Scrofa) Impacts On Agricultural Producers: Insights From A Texas Case Study, Keith M. Carlisle, Nicole Didero, Sophie Mckee, Julie Elser, Stephanie A. Shwiff Dec 2021

Towards A More Comprehensive Understanding Of Wild Pig (Sus Scrofa) Impacts On Agricultural Producers: Insights From A Texas Case Study, Keith M. Carlisle, Nicole Didero, Sophie Mckee, Julie Elser, Stephanie A. Shwiff

United States Department of Agriculture Wildlife Services: Staff Publications

This research investigates the impacts of invasive wild pigs (Sus scrofa Linneaus) on agricultural producers in Texas, with the aim of identifying and describing all categories of wild pig impacts and quantifying the extent of producers’ over- or underestimation of their total wild pig-related costs in 2018, as compared to calculations based upon data subsequently provided by the producers about individual wild pig-related costs and losses. Based on interviews with 23 producers in 16 Texas counties, we identified more than 20 discrete categories of negative impacts and negligible positive impacts associated with wild pigs. Among them were categories that have …


Landscape Transformations Produce Favorable Roosting Conditions For Turkey Vultures And Black Vultures, Jacob E. Hill, Kenneth F. Kellner, Bryan M. Kluever, Michael L. Avery, John S. Humphrey, Eric A. Tillman, Travis L. Devault, Jerrold L. Belant Dec 2021

Landscape Transformations Produce Favorable Roosting Conditions For Turkey Vultures And Black Vultures, Jacob E. Hill, Kenneth F. Kellner, Bryan M. Kluever, Michael L. Avery, John S. Humphrey, Eric A. Tillman, Travis L. Devault, Jerrold L. Belant

United States Department of Agriculture Wildlife Services: Staff Publications

Recent increases in turkey vulture (Cathartes aura) and black vulture (Coragyps atratus) populations in North America have been attributed in part to their success adapting to human-modified landscapes. However, the capacity for such landscapes to generate favorable roosting conditions for these species has not been thoroughly investigated. We assessed the role of anthropogenic and natural landscape elements on roosting habitat selection of 11 black and 7 turkey vultures in coastal South Carolina, USA using a GPS satellite transmitter dataset derived from previous research. Our dataset spanned 2006–2012 and contained data from 7916 nights of roosting. Landscape …


Reproductive Success Of Captive-Reared Allegheny Woodrats (Neotoma Magister) Released Into Genetically Depauperate Populations, Miracle M. Davis, Timothy J. Smyser, Scott A. Johnson, Joseph Duchamp, Jeffery L. Larkin, Robert K. Swihart, Jacqueline M. Doyle Dec 2021

Reproductive Success Of Captive-Reared Allegheny Woodrats (Neotoma Magister) Released Into Genetically Depauperate Populations, Miracle M. Davis, Timothy J. Smyser, Scott A. Johnson, Joseph Duchamp, Jeffery L. Larkin, Robert K. Swihart, Jacqueline M. Doyle

United States Department of Agriculture Wildlife Services: Staff Publications

Habitat fragmentation and degradation have led to a proliferation of small and isolated populations that are vulnerable to genetic erosion. Reduction in habitat and concomitant declines in population connectivity can expediate the collapse of species that exist as natural metapopulations. In recent years, Allegheny woodrats (Neotoma magister) have experienced local extirpations and declines in genetic diversity across their range due to disease-related mortality, reduced food availability, and disruption of connectivity among subpopulations. In response, we developed a captive-breeding program to facilitate genetic management of isolated woodrat populations in Indiana. Between 2010 and 2012, 27 captive-reared individuals were released to four …


Economic Estimates Of Wild Hog (Sus Scrofa) Damage And Control Among Young Forest Plantations In Alabama, Micah Fern, Rebecca Barlow, Chris Slootmaker, John Kush, Stephanie Shwiff, Larry Teeter, Jim Armstrong Dec 2021

Economic Estimates Of Wild Hog (Sus Scrofa) Damage And Control Among Young Forest Plantations In Alabama, Micah Fern, Rebecca Barlow, Chris Slootmaker, John Kush, Stephanie Shwiff, Larry Teeter, Jim Armstrong

United States Department of Agriculture Wildlife Services: Staff Publications

Operating as ecological engineers, the increased distribution and abundance of wild hogs (Sus scrofa) has caused considerable socio-economic impacts. The international scope of economic research providing wild hog damage estimates are often confined to agricultural crops, while damage estimates among forest plantations are lacking. In Alabama, private landowners hold the majority of timberland acreage and are less equipped to absorb financial losses from wild hog damage than their industrial counterparts. A survey was conducted to estimate the economic impact of wild hogs, namely costs of damage and control, to privately owned forestlands. The survey was distributed in the …


Sex And Nest Type Influence Avian Blood Parasite Prevalence In A High-Elevation Bird Community, Marina D. Rodriguez, Paul F. Doherty, Antoinette J. Piaggio, Kathryn P. Huyvaert Dec 2021

Sex And Nest Type Influence Avian Blood Parasite Prevalence In A High-Elevation Bird Community, Marina D. Rodriguez, Paul F. Doherty, Antoinette J. Piaggio, Kathryn P. Huyvaert

United States Department of Agriculture Wildlife Services: Staff Publications

Background: The prevalence of avian haemosporidian parasites and the factors influencing infection in the Colorado Rocky Mountains are largely unknown. With climate change expected to promote the expansion of vector and avian blood parasite distributions, baseline knowledge and continued monitoring of the prevalence and diversity of these parasites is needed.

Methods: Using an occupancy modeling framework, we conducted a survey of haemosporidian parasite species infecting an avian community in the Colorado Rocky Mountains in order to estimate the prevalence and diversity of blood parasites and to investigate species-level and individual-level characteristics that may influence infection.

Results: We estimated the prevalence …


Responses Of Turkey Vultures To Unmanned Aircraft Systems Vary By Platform, Morgan B. Pfeiffer, Bradley F. Blackwell, Thomas W. Seamans, Bruce N. Buckingham, Joshua L. Hoblet, Patrice E. Baumhardt Dec 2021

Responses Of Turkey Vultures To Unmanned Aircraft Systems Vary By Platform, Morgan B. Pfeiffer, Bradley F. Blackwell, Thomas W. Seamans, Bruce N. Buckingham, Joshua L. Hoblet, Patrice E. Baumhardt

United States Department of Agriculture Wildlife Services: Staff Publications

A challenge that conservation practitioners face is manipulating behavior of nuisance species. The turkey vulture (Cathartes aura) can cause substantial damage to aircraft if struck. The goal of this study was to assess vulture responses to unmanned aircraft systems (UAS) for use as a possible dispersal tool. Our treatments included three platforms (fixed-wing, multirotor, and a predator-like ornithopter [powered by flapping flight]) and two approach types (30 m overhead or targeted towards a vulture) in an operational context. We evaluated perceived risk as probability of reaction, reaction time, flight-initiation distance (FID), vulture remaining index, and latency to return. …


Linking Plot And Landscape Level Phenology, Alejandra Flores Dec 2021

Linking Plot And Landscape Level Phenology, Alejandra Flores

Open Access Theses & Dissertations

Plant phenology has become popularize since the 1990s to help understand the effects of climate change on vegetation, it is a way to study the patterns of leaf-out, flowering, and senescing of the life-cycle of the plant. The timing from start of season (SOS) to end-of-season (EOS) of plant leaf-out development has important implication on ecosystem productivity and carbon cycling across ecological scales from individual trees to whole regions. The need for plant phenology studies in dryland are highly anticipated, since they make up 40% of the terrestrial landscape and recently have shown the play an important role in the …


Demystifying The Practices Of Software Design And The Impact On Codebase Quality And Sustainability, Khandoker Rahad Dec 2021

Demystifying The Practices Of Software Design And The Impact On Codebase Quality And Sustainability, Khandoker Rahad

Open Access Theses & Dissertations

Software systems continue to increase in size and complexity to match the ever-increasing user expectations. Designing and engineering such complex software systems brings about unique challenges. Complex systems are not only expensive to develop, but even more expensive to maintain. Most software systems must adapt to continuously changing business contexts and requirements. In the process, software accumulates arbitrary complexities making its maintenance even more challenging. Design and modeling are the primary methodologies to develop reliable, sustainable, maintainable systems. The development of novel design languages, tools, and methodologies is frequently not able to keep up with the exponential increase in software …


A New Algorithm For Robust Affine-Invariant Clustering, Andrews Tawiah Anum Dec 2021

A New Algorithm For Robust Affine-Invariant Clustering, Andrews Tawiah Anum

Open Access Theses & Dissertations

Cluster analysis is an unsupervised machine learning technique commonly employed to partition a dataset into distinct categories referred to as clusters. The k-means algorithm is a prominent distance-based clustering method. Despite its overwhelming popularity, the algorithm is not invariant under non-singular linear transformations and is not robust, i.e., can be unduly influenced by outliers. To address these deficiencies, we propose an alternative clustering procedure based on minimizing a “trimmed” variant of the negative log-likelihood function. We develop a “concentration step”, vaguely reminiscent of the classical Lloyd’s algorithm, that can iteratively reduce the objective function. Multiple real and synthetic datasets are …


Synthesis, Characterization, And Direct-Ink-Writing Of Syntactic Foams, Andrea Irigoyen Dec 2021

Synthesis, Characterization, And Direct-Ink-Writing Of Syntactic Foams, Andrea Irigoyen

Open Access Theses & Dissertations

This project encompasses three different methods to fabricate syntactic foams using a PDMS matrix i.e., hollow spheres inclusion, pore generator leaching by solvent, and emulsion. The foam formation by using polysiloxane hollow spheres is done in a 3-step process. The first step is to create a core of polystyrene following a dispersion polymerization process. The goal for the size of the pore is to monodisperse and have an average diameter of 5-10 μm, so the polystyrene core must be as well within that range. After that, the cores are coated with a polysiloxane shell by following a polymerization by condensation …


Transboundary Air Quality Governance: A Case Study Of The Paso Del Norte Air Basin 1940-2000, Laura Margarita Uribarri Dec 2021

Transboundary Air Quality Governance: A Case Study Of The Paso Del Norte Air Basin 1940-2000, Laura Margarita Uribarri

Open Access Theses & Dissertations

For thousands of years, the Paso del Norte region which today includes Ciudad Juárez, Chihuahua, El Paso, Texas, and Sunland Park, New Mexico, has been a strategic location by virtue of its geographic positioning at the lowest and easiest passage across the continental divide. During the 19th and 20th centuries as railroad networks connected the region to the far reaches of the U.S. and the interior of Mexico, it became a nexus for natural resource and labor extraction. Mining and smelting industries were later joined by agriculture and manufacturing to benefit from the transportation network and the abundance of labor. …


A Integrated Approach Of Deep Learning And Augmented Reality For Pneumonia Detection In Chest X-Ray Images, Jeevarathinam Senthilkumar Dec 2021

A Integrated Approach Of Deep Learning And Augmented Reality For Pneumonia Detection In Chest X-Ray Images, Jeevarathinam Senthilkumar

Open Access Theses & Dissertations

Pneumonia is a viral or fungal illness that spreads to the lungs of the human body, causing fluid to accumulate in the lungs' air sacs. Millions of people are affected by this disease each year. One of the most common radiological diagnostics for diagnosing and screening this kind of sickness is a chest X-ray. The most commonly available radiological test for diagnosing and screening this kind of illness is a chest X-ray. An inaccurate diagnosis, especially over-diagnosis and under-diagnosis, is a common issue in the medical sector. As another issue, human-assisted diagnosis has limitations like the availability of an expert, …


Collaborcrack: A Collaborative Password Cracking Solution For Windows Penetration Testing, Andrew Griess Dec 2021

Collaborcrack: A Collaborative Password Cracking Solution For Windows Penetration Testing, Andrew Griess

Theses/Capstones/Creative Projects

Cybersecurity professionals attempt to crack password hashes during penetration tests to determine if they are strong enough. A password hash is a way to encode a password securely. This paper describes a proof-of-concept program called CollaborCrack, a team-based password cracking solution. CollaborCrack addresses the issues of computational complexity, remote cracking security, duplication of work, and the cost associated with password cracking. To address computational complexity, CollaborCrack enables remote password cracking. Remote cracking requires additional safeguards, which CollaborCrack mitigates by storing sensitive information locally. To reduce the duplication of work, CollaborCrack provides a shared interface designed around collaboration and teamwork. CollaborCrack …


Toi-2109: An Ultrahot Gas Giant On A 16 Hr Orbit, I. Wong, A. Shporer, G. Zhou, D. Kitzmann, T. D. Komacek, X. Tan, R. Tronsgaard, L. A. Buchhave, S. Vissapragada, M. Greklek-Mckeon, J. E. Rodriguez, J. P. Ahlers, S. N. Quinn, E. Furlan, S. B. Howell, A. Bieryla, K. Heng, H. A. Knutson, K. A. Collins, K. K. Mcleod, P. Berlind, P. Brown, M. L. Calkins, J. P. De Leon, E. Esparza-Borges, G. A. Esquerdo, A. Fukui, T. Gan, E. Girardin, C. L. Gnilka, M. Ikoma, Eric L.N. Jensen, J. Kielkopf, T. Kodama, S. Kurita, K. V. Lester, P. Lewin, G. Marino, F. Murgas, N. Narita, E. Pallé, R. P. Schwarz, K. G. Stassun, M. Tamura, N. Watanabe, B. Benneke, G. R. Ricker, D. W. Latham, R. Vanderspek, S. Seager, J. N. Winn, J. M. Jenkins, D. A. Caldwell, W. Fong, C. X. Huang, I. Mireles, J. E. Schlieder, B. Shiao, J. N. Villaseñor Dec 2021

Toi-2109: An Ultrahot Gas Giant On A 16 Hr Orbit, I. Wong, A. Shporer, G. Zhou, D. Kitzmann, T. D. Komacek, X. Tan, R. Tronsgaard, L. A. Buchhave, S. Vissapragada, M. Greklek-Mckeon, J. E. Rodriguez, J. P. Ahlers, S. N. Quinn, E. Furlan, S. B. Howell, A. Bieryla, K. Heng, H. A. Knutson, K. A. Collins, K. K. Mcleod, P. Berlind, P. Brown, M. L. Calkins, J. P. De Leon, E. Esparza-Borges, G. A. Esquerdo, A. Fukui, T. Gan, E. Girardin, C. L. Gnilka, M. Ikoma, Eric L.N. Jensen, J. Kielkopf, T. Kodama, S. Kurita, K. V. Lester, P. Lewin, G. Marino, F. Murgas, N. Narita, E. Pallé, R. P. Schwarz, K. G. Stassun, M. Tamura, N. Watanabe, B. Benneke, G. R. Ricker, D. W. Latham, R. Vanderspek, S. Seager, J. N. Winn, J. M. Jenkins, D. A. Caldwell, W. Fong, C. X. Huang, I. Mireles, J. E. Schlieder, B. Shiao, J. N. Villaseñor

Physics & Astronomy Faculty Works

We report the discovery of an ultrahot Jupiter with an extremely short orbital period of 0.67247414 ± 0.00000028 days (∼16 hr). The 1.347 ± 0.047 RJup planet, initially identified by the Transiting Exoplanet Survey Satellite (TESS) mission, orbits TOI-2109 (TIC 392476080)—a Teff ∼ 6500 K F-type star with a mass of 1.447 ± 0.077 M, a radius of 1.698 ± 0.060 R, and a rotational velocity of v sin i* = 81.9 ± 1.7 km s⁻¹. The planetary nature of TOI-2109b was confirmed through radial-velocity measurements, which yielded a planet mass of 5.02 …


2d Vs 3d Tracking In Bacterial Motility Analysis, Jacqueline Acres, Jay Nadeau Dec 2021

2d Vs 3d Tracking In Bacterial Motility Analysis, Jacqueline Acres, Jay Nadeau

Physics Faculty Publications and Presentations

Digital holographic microscopy provides the ability to observe throughout a large volume without refocusing. This capability enables simultaneous observations of large numbers of microorganisms swimming in an essentially unconstrained fashion. However, computational tools for tracking large 4D datasets remain lacking. In this paper, we examine the errors introduced by tracking bacterial motion as 2D projections vs. 3D volumes under different circumstances: bacteria free in liquid media and bacteria near a glass surface. We find that while XYZ speeds are generally equal to or larger than XY speeds, they are still within empirical uncertainties. Additionally, when studying dynamic surface behavior, the …


Studying Users Interactions And Behavior In Social Media Using Natural Language Processing, Sultan Alshamrani Dec 2021

Studying Users Interactions And Behavior In Social Media Using Natural Language Processing, Sultan Alshamrani

Electronic Theses and Dissertations, 2020-2023

Social media platforms have been growing at a rapid pace, attracting users' engagement with the online content due to their convenience facilitated by many useful features. Such platforms provide users with interactive options such as likes, dislikes as well as a way of expressing their opinions in the form of text (i.e., comments). As more people engage in different social media platforms, such platforms will increase in both size and importance. This growth in social media data is becoming a vital new area for scholars and researchers to explore this new form of communication. The huge data from social media …


Sedimentary Dna And Molecular Evidence For Early Human Occupation Of The Faroe Islands, Lorelei Curtin, William J. D’Andrea, Nicholas L. Balascio, Sabrina Shirazi, Beth Shapiro, Gregory A. De Wet, Raymond S. Bradley, Jostein Bakke Dec 2021

Sedimentary Dna And Molecular Evidence For Early Human Occupation Of The Faroe Islands, Lorelei Curtin, William J. D’Andrea, Nicholas L. Balascio, Sabrina Shirazi, Beth Shapiro, Gregory A. De Wet, Raymond S. Bradley, Jostein Bakke

Geosciences: Faculty Publications

The Faroe Islands, a North Atlantic archipelago between Norway and Iceland, were settled by Viking explorers in the mid-9th century CE. However, several indirect lines of evidence suggest earlier occupation of the Faroes by people from the British Isles. Here, we present sedimentary ancient DNA and molecular fecal biomarker evidence from a lake sediment core proximal to a prominent archaeological site in the Faroe Islands to establish the earliest date for the arrival of people in the watershed. Our results reveal an increase in fecal biomarker concentrations and the first appearance of sheep DNA at 500 CE (95% confidence interval …


A Deep Recurrent Neural Network With Iterative Optimization For Inverse Image Processing Applications, Masaki Ikuta Dec 2021

A Deep Recurrent Neural Network With Iterative Optimization For Inverse Image Processing Applications, Masaki Ikuta

Theses and Dissertations

Many algorithms and methods have been proposed for inverse image processing applications, such as super-resolution, image de-noising, and image reconstruction, particularly with the recent surge of interest in machine learning and deep learning methods.

As for Computed Tomography (CT) image reconstruction, the most recently proposed methods are limited to image domain processing, where deep learning is used to learn the mapping between a true image data set and a noisy image data set in the image domain. While deep learning-based methods can produce higher quality images than conventional model-based algorithms, these methods have a limitation. Deep learning-based methods used in …


Synthesis Of Phosphatidylethanolamine Lipids For Model Studies Of The Cell Membrane, John Hayford G. Teye-Kau Dec 2021

Synthesis Of Phosphatidylethanolamine Lipids For Model Studies Of The Cell Membrane, John Hayford G. Teye-Kau

Electronic Theses and Dissertations

Concerns about global warming have resulted in a surge of research into alternatives to fossil fuels. In recent years, biofuels have gained traction due to their low environmental impact. Biofuel production most commonly employs microorganisms to convert biomass to fuel for industrial and transportation applications. Compounds made in biofuel production, however, are toxic to cell membranes and disrupt their integrity, harming the microorganisms and limiting biofuel yield. A key to overcoming this challenge is understanding how fuels interact with microorganisms’ cell membranes, which perform a host of functions, including transport, cell recognition, transduction, and movement. Phospholipids are the cell membrane’s …


Mobilizing Discomfort For Water Security As A Human Right: A Newspaper Analysis Of Social Conflict In South Africa, Madison Gonzalez Dec 2021

Mobilizing Discomfort For Water Security As A Human Right: A Newspaper Analysis Of Social Conflict In South Africa, Madison Gonzalez

Graduate Program in International Studies Theses & Dissertations

There are 884 million people globally that do not have access to improved drinking water, while 2.5 billion do not have improved access to sanitation (Office of the High Commissioner for Human Rights, 2010). Those living in informal settlements and slums—what I call the ‘solidaric disaffiliated’ zones—represent one such location where individuals around the world have found themselves in a situation of neglected crisis as their geographic, economic, and social expulsion pushes them beyond the reach of opportunity and access to basic human rights such as water and sanitation. As individuals feel their dignity deteriorating due to the extreme precarity …


Monarch Science Observer, Volume 12, College Of Sciences, Old Dominion University Dec 2021

Monarch Science Observer, Volume 12, College Of Sciences, Old Dominion University

College of Sciences Newsletter

Winter 2021 issue of Monarch Science Observer, ODU College of Sciences Newsletter.


Estimation And Interpretation Of Machine Learning Models With Customized Surrogate Model, Mudabbir Ali, Asad Masood Khattak, Zain Ali, Bashir Hayat, Muhammad Idrees, Zeeshan Pervez, Kashif Rizwan, Tae Eung Sung, Ki Il Kim Dec 2021

Estimation And Interpretation Of Machine Learning Models With Customized Surrogate Model, Mudabbir Ali, Asad Masood Khattak, Zain Ali, Bashir Hayat, Muhammad Idrees, Zeeshan Pervez, Kashif Rizwan, Tae Eung Sung, Ki Il Kim

All Works

Machine learning has the potential to predict unseen data and thus improve the productivity and processes of daily life activities. Notwithstanding its adaptiveness, several sensitive applications based on such technology cannot compromise our trust in them; thus, highly accurate machine learning models require reason. Such models are black boxes for end-users. Therefore, the concept of interpretability plays the role if assisting users in a couple of ways. Interpretable models are models that possess the quality of explaining predictions. Different strategies have been proposed for the aforementioned concept but some of these require an excessive amount of effort, lack generalization, are …


Theoretical Models Of Integration Of Interactive Learning Technologies Into Teaching: A Systematic Literature Review, Laila Mohebi Dec 2021

Theoretical Models Of Integration Of Interactive Learning Technologies Into Teaching: A Systematic Literature Review, Laila Mohebi

All Works

With the fast progress of technology and the vast amount of research papers related to technology integration in education being published yearly, a study that reviews models used in these papers is needed. Therefore, this paper (1) reviewed and analysed theoretical frameworks with models used for integration of technology in classrooms, (2) reviewed studies that discussed the impact of technology integration on students' learning capabilities, and (3) discussed the importance of preparing teachers to effectively integrate technology in teaching. The models reviewed were: Teacher Thoughts and Action Process (TTAP), Theory of Planned Behavior, Expectancy-Value Theory of Achievement Motivation (EVAM), Substitution …


Building Action Sets In A Deep Reinforcement Learner, Yongzhao Wang, Arunesh Sinha, Sky C.H. Wang, Michael P. Wellman Dec 2021

Building Action Sets In A Deep Reinforcement Learner, Yongzhao Wang, Arunesh Sinha, Sky C.H. Wang, Michael P. Wellman

Research Collection School Of Computing and Information Systems

In many policy-learning applications, the agent may execute a set of actions at each decision stage. Choosing among an exponential number of alternatives poses a computational challenge, and even representing actions naturally expressed as sets can be a tricky design problem. Building upon prior approaches that employ deep neural networks and iterative construction of action sets, we introduce a reward-shaping approach to apportion reward to each atomic action based on its marginal contribution within an action set, thereby providing useful feedback for learning to build these sets. We demonstrate our method in two environments where action spaces are combinatorial. Experiments …


Gps-Denied Navigation Using Synthetic Aperture Radar Images And Neural Networks, Teresa White Dec 2021

Gps-Denied Navigation Using Synthetic Aperture Radar Images And Neural Networks, Teresa White

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Unmanned aerial vehicles (UAV) often rely on GPS for navigation. GPS signals, however, are very low in power and easily jammed or otherwise disrupted. This paper presents a method for determining the navigation errors present at the beginning of a GPS-denied period utilizing data from a synthetic aperture radar (SAR) system. This is accomplished by comparing an online-generated SAR image with a reference image obtained a priori. The distortions relative to the reference image are learned and exploited with a convolutional neural network to recover the initial navigational errors, which can be used to recover the true flight trajectory throughout …


Intelligent Traffic Management: From Practical Stochastic Path Planning To Reinforcement Learning Based City-Wide Traffic Optimization, Kamilia Ahmadi Dec 2021

Intelligent Traffic Management: From Practical Stochastic Path Planning To Reinforcement Learning Based City-Wide Traffic Optimization, Kamilia Ahmadi

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This research focuses on intelligent traffic management including stochastic path planning and city scale traffic optimization. Stochastic path planning focuses on finding paths when edge weights are not fixed and change depending on the time of day/week. Then we focus on minimizing the running time of the overall procedure at query time utilizing precomputation and approximation. The city graph is partitioned into smaller groups of nodes and represented by its exemplar. In query time, source and destination pairs are connected to their respective exemplars and the path between those exemplars is found. After this, we move toward minimizing the city …


On The Geometry Of The Moduli Space Of Certain Lattice Polarized K3 Surfaces And Their Picard-Fuchs Operators, Michael T. Schultz Dec 2021

On The Geometry Of The Moduli Space Of Certain Lattice Polarized K3 Surfaces And Their Picard-Fuchs Operators, Michael T. Schultz

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

K3 surfaces have a long and rich study in mathematics, and more recently in physics via string theory. Often, K3 surfaces come in multiparameter families - the parameters describing these surfaces fit together to form their own geometric space, a so-called moduli space. In particular, the moduli spaces of K3 surfaces equipped with a lattice polarization can sometimes be constructed explicitly, which subsequently reveals important information about the original K3 surface.

In this work, we construct such families explicitly from certain rational elliptic surfaces via the so-called mixed-twist construction of Doran & Malmendier, which in turn produces the moduli …


Interfaces And Dynamics In Polymeric 3d Printing And Crystalline Polymer Blends, Stevenson C. Perryman Dec 2021

Interfaces And Dynamics In Polymeric 3d Printing And Crystalline Polymer Blends, Stevenson C. Perryman

Doctoral Dissertations

This dissertation presents experimental work that provide a foundation to rationally improve fused filament fabrication (FFF) and immiscible blend compatibilization. Objects generated from additive manufacturing processes, such as FFF, have intrinsic structural weaknesses which include two project specific examples: structural anisotropy and irreversible thermal strain. Due to low adhesion between individual print layers that results in macroscopic defects, the mechanical strength of printed objects when force is applied perpendicular to the build orientation is drastically reduced. In the first dissertation chapter, we present a protocol to produce interlayer covalent bonds by depositing multi-amine additives between individual layers of a print …


A Human-Centric System For Symbolic Reasoning About Code, Megan Fowler Dec 2021

A Human-Centric System For Symbolic Reasoning About Code, Megan Fowler

All Dissertations

While testing and tracing on specific input values are useful starting points for students to understand program behavior, ultimately students need to be able to reason rigorously and logically about the correctness of their code on all inputs without having to run the code. Symbolic reasoning is reasoning abstractly about code using arbitrary symbolic input values, as opposed to specific concrete inputs.

The overarching goal of this research is to help students learn symbolic reasoning, beginning with code containing simple assertions as a foundation and proceeding to code involving data abstractions and loop invariants. Toward achieving this goal, this research …