Digital Commons Network^™

Towards Long-Term Fairness In Sequential Decision Making, Yaowei Hu

Graduate Theses and Dissertations

With the development of artificial intelligence, automated decision-making systems are increasingly integrated into various applications, such as hiring, loans, education, recommendation systems, and more. These machine learning algorithms are expected to facilitate faster, more accurate, and impartial decision-making compared to human judgments. Nevertheless, these expectations are not always met in practice due to biased training data, leading to discriminatory outcomes. In contemporary society, countering discrimination has become a consensus among people, leading the EU and the US to enact laws and regulations that prohibit discrimination based on factors such as gender, age, race, and religion. Consequently, addressing algorithmic discrimination has …

Comparative Analysis Of Teacher Effects Parameters In Models Used For Assessing School Effectiveness: Value-Added Models & Persistence, Merlin J. Kamgue

Graduate Theses and Dissertations

Longitudinal measures for students have become increasingly popular to estimate the effects of individual teachers and schools. Value-added models are one of the approaches using longitudinal data to evaluate teachers and schools. In the value-added model (VAM) literature, many statistical approaches have been developed and used to estimate teacher or school effects on student learning. This study opted to use a Bayesian multivariate model for evaluating teacher effects. The generalized persistence models can handle longitudinal data, not vertically scaled, allowing for a below-par teacher’s effects correlation across test administrations. This study first generated longitudinal students’ test score data and used …

Towards Multi-Modal Interpretable Video Understanding, Quang Sang Truong

Graduate Theses and Dissertations

This thesis introduces an innovative approach to video comprehension, which simulates human perceptual mechanisms and establishes a comprehensible and coherent narrative representation of video content. At the core of this approach lies the creation of a Visual-Linguistic (VL) feature for an interpretable video portrayal and an adaptive attention mechanism (AAM) aimed at concentrating solely on principal actors or pertinent objects while modeling their interconnections. Taking cues from the way humans disassemble scenes into visual and non-visual constituents, the proposed VL feature characterizes a scene via three distinct modalities: (i) a global visual environment, providing a broad contextual comprehension of the …

Geospatial Analysis Of Weathering And Recession On Architectural Limestone At The 1891 Powerhouse/Icehouse In Eureka Springs, Arkansas, Stuart Bruce Wright

Graduate Theses and Dissertations

The objective of this study of the architectural limestone of the 1891 Powerhouse/Icehouse in Eureka Springs, Arkansas was to analyze the environmental factors that influenced the deterioration and surface recession of this historical stone structure. The focus of this research was to examine and establish a baseline study that may assist in future monitoring and documentation of this historic limestone structure on stone weathering. A replicable methodology was specifically created toward this baseline research in hopes that it represented a solid baseline study. Observations and data analyses revealed the relationship between the architectural limestone building structure and the dominating recession …

Exploring Success Factors Of Women Senior Leaders In The United States Paper Manufacturing Operations Industry: A Phenomenological Study, Ericka Eggleston

Graduate Theses and Dissertations

The purpose of this study is to understand how women describe their journey to becoming senior leaders within the operations sector of the Paper Manufacturing Industry. This study will provide insights about how women in the male-dominated Paper Manufacturing Industry (PMI) assumed leadership positions. This pre-registered study will offer the framework for this study to be carried out at the University of Arkansas. The researcher will apply a descriptive phenomenological approach that will use semi-structured questions to understand the strategies they used to navigate their career path. Snowball sampling will be used to select 5-15 participants who provide their perceptions …

Development Of A Historic Digital Elevation Model (Hdem) From Archival Aerial Imagery Over The Black Mountain Alluvial Fan, Canada, Emma Menio

Graduate Theses and Dissertations

In a rapidly changing Arctic, reconstructing landscapes pre-warming is essential to understanding impacts due to climate-inducted geomorphic change. High-latitude elevation datasets extend temporally back to the 2000s, while region-wide warming became measurable in the 1980s. Historic aerial imagery archives provide datasets of high-resolution imagery from the mid- to late- 1900s with stereo-capability that can be harnessed to create historic digital elevation models, or hDEMs. A major issue with reconstructing a surface from the past is finding a way to constrain it in space, given a lack of ground control from that era, especially at high latitudes. The main purpose of …

Deep Learning For Photovoltaic Characterization, Adrian Manuel De Luis Garcia

Graduate Theses and Dissertations

This thesis introduces a novel approach to Photovoltaic (PV) installation segmentation by proposing a new architecture to understand and identify PV modules from overhead imagery. Pivotal to this concept is the creation of a new Transformer-based network, S3Former, which focuses on small object characterization and modelling intra- and inter- object differentiation inside an image. Accurate mapping of PV installations is pivotal for understanding their adoption and guiding energy policy decisions. Drawing insights from current Deep Learning methodologies for image segmentation and building upon State-of-the-Art (SOTA) techniques in solar cell mapping, this work puts forth S3Former with the following enhancements: 1. …

Sensory Input To Cortex Encoded On Low-Dimensional Periphery-Correlated Subspaces, Andrea K. Barreiro, Antonio J. Fontenele, Cheng Ly, Prashant Chama Raju, Shree Hari Gautam, Woodrow L. Shew

Physics Faculty Publications and Presentations

As information about the world is conveyed from the sensory periphery to central neural circuits, it mixes with complex ongoing cortical activity. How do neural populations keep track of sensory signals, separating them from noisy ongoing activity? Here, we show that sensory signals are encoded more reliably in certain low-dimensional subspaces. These coding subspaces are defined by correlations between neural activity in the primary sensory cortex and upstream sensory brain regions; the most correlated dimensions were best for decoding. We analytically show that these correlation-based coding subspaces improve, reaching optimal limits (without an ideal observer), as noise correlations between cortex …

Uncertainty In Streamflow Measurements Significantly Impacts Estimates Of Downstream Nitrate Export, Shannon L. Speir, C. Nathan Jones, Arial J. Shogren, Carla L. Atkinson

Crop, Soil and Environmental Sciences Faculty Publications and Presentations

Across watershed science, two key variables emerge–streamflow and solute concentration–which serve as the basis for efforts ranging from basic watershed biogeochemistry research to policy decisions surrounding watershed management. However, we rarely account for how error in discharge (Q) impacts estimates of downstream nutrient loading. Here, we examined the impact of uncertainty in streamflow measurements on estimates of downstream nitrate export using publicly available data from the U.S. Geological Survey (USGS). We characterized how uncertainty in stage-discharge relationships impacts annual flux estimates across 70 USGS gages. Our results indicate the interquartile range of relative error in Q was 33% across these …

Exploration Of Academic Outcomes In Arkansas's Four-Day School Weeks And Year-Round Calendars, Sarah Mckenzie, Josh Mcgee, Kathryn L. Barnes, Charlene A. Reid

Policy Briefs

This brief provides an overview of the findings from a research report examining the academic outcomes of Arkansas school districts using a four-day school week or year-round calendar. We aim to shed light on trends related to academic outcomes. We assess the impacts of recent calendar changes in this context and make recommendations.

Exploring Academic Outcomes In Arkansas Schools: A Study Of Four-Day School Week And Year-Round Calendar Districts, Kate Barnes, Sarah Mckenzie

Arkansas Education Reports

In 2021, Arkansas's state legislature passed Act 688 allowing school districts to adopt non-traditional calendars. Districts could choose from four calendar options: traditional, four-day school weeks (4DSW), year-round calendar(YRC), and alternative. During the 2022-23 school year, 33 districts adopted new calendars; twenty-seven districts operated using a 4DSW, and six used a YRC. Several more districts adopted 4DSW in the 2023-24 school year. Atpresent, thirty-four Arkansas districts use a 4DSW. This report used publicly available data from the Arkansas Department of Education to explore the relationship between adoption of a 4DSW or YRC and the following student outcomes: academic growth, academic …

Advanced Placement (Ap) & Concurrent Enrollment (Ce) Courses And College Outcomes, Sarah Mckenzie, Josh Mcgee, Rian R. Djita

Policy Briefs

For 20 years, Arkansas school districts have been required to provide access to advanced coursework through Advanced Placement (AP) and Concurrent Enrollment (CE) courses. Despite universal access, we find that enrollment in AP or CE courses still varies across students’ demographic groups. However, the findings also highlight improved postsecondary outcomes for several student groups.

The Role Of Ap & Concurrent Courses On Student Postsecondary Outcomes, Out-Of-State Choice, And College Selectivity, Rian R. Djita, Andy Parra-Martinez, Jonathan Wai, Sarah C. Mckenzie

Arkansas Education Reports

Literature on Advanced Placement (AP) and dual or concurrent enrollment (CE) courses shows that entry to and completion of these rigorous courses can increase students’ cognitive and non-cognitive outcomes. Issues of equity remain as White students and students from more affluent backgrounds tend to enroll in these courses at much higher rates than minoritized students and low-income students. Arkansas implemented a universal policy mandating all school districts provide access to AP and CE courses. Within this context, we investigate the relationship between enrollment in these courses and student postsecondary outcomes. Despite universal access, we find that enrollment in AP or …

Innovative Approaches To Poultry Processing Wastewater Treatment: The Stainless Steel Ultrafiltration Membrane As A Viable Option, Saubana Olorunrola Dada, Chidambaram Thamariselvan, Mahmood Jebur, Sumith Ranil Wickramasinghe

Chemical Engineering Faculty Publications and Presentations

In pursuit of sustainability, we explored replacing conventional dissolved air floatation (DAF) in poultry processing wastewater (PPW) treatment with a precisely tuned 0.02 µm stainless-steel ultrafiltration (SSUF) membrane. SSUF is a robust, homogenously porous membrane with strong chemical resistance, ease of cleaning, and exceptional resistance to organic fouling. Unlike polymeric membranes, it can be regenerated multiple times, making it a cost-effective choice due to its compatibility with harsh chemical cleaning. The PPW used for the study was untreated wastewater from all processing units and post-initial screening. Our study revealed the SSUF membrane’s exceptional efficiency at eliminating contaminants. It achieved an …

Growth Of Germanium Thin Films On Sapphire Using Molecular Beam Epitaxy, Emmanuel Wangila, Peter Lytvyn, Hryhorii Stanchu, Calbi Gunder, Fernando Maia De Oliveira, Samir Saha, Subhashis Das, Niroshi Eldose, Chen Li, Mohammad Zamani-Alavijeh, Mourad Benamara, Yuriy I. Mazur, Shui-Qing Yu, Gregory J. Salamo

Electrical Engineering Faculty Publications and Presentations

Germanium films were grown on c-plane sapphire with a 10 nm AlAs buffer layer using molecular beam epitaxy. The effects of Ge film thickness on the surface morphology and crystal structure were investigated using ex situ characterization techniques. The nucleation of Ge proceeds by forming (111) oriented three-dimensional islands with two rotational twin domains about the growth axis. The boundaries between the twin grains are the origin of the 0.2% strain and tilt grains. The transition to a single-grain orientation reduces the strain and results in a better-quality Ge buffer. Understanding the role of thickness on material quality during the …

Web 2 Vs. Web 3 Paths To The Metaverse: Who Is Leading? Who Should Lead?, Le Kuai, Mary Lacity, Jeffrey K. Mullins

Information Systems Faculty Publications and Presentations

Our research investigates two questions: Who is leading the metaverse? Who should lead? The questions are important because metaverse will have significant consequences for individuals, businesses, and society. We examined the current leaders of metaverse on two evolutionary paths, namely Web 2 and Web 3. Based on regulatory reports, corporate press releases, and patents, we found that only a handful of Web 2 companies are “all-in” on metaverse, and at least one of these enterprises, Meta, is on track to end up as a dominant platform provider. Based on market capitalization, user activity, and patents, only a handful of Web …

University Of Arkansas, Chemistry And Biochemistry Department Graduate Student Publications, 2018- November 2023. 39p., Jeremy Smith, Lutishoor Salisbury

University Libraries Faculty Publications and Presentations

This report provides a compilation of the research publications by the Chemistry and Biochemistry (CHBC) Graduate students for the period: 2018-November 2023. It includes publications by the CHBC graduates and those where a CHBC faculty was the main advisor. It includes a summary of the research. The listing is organized according to type of publications within specific years.

University Of Arkansas, Chemistry And Biochemistry Department Research Publications, 2014- November 2023. 107p., Jeremy Smith, Lutishoor Salisbury

University Libraries Faculty Publications and Presentations

This report provides a compilation of the research publications by the Chemistry and Biochemistry faculty for the period: 2014 - November 2023. The information was gathered from major databases in science and technology including Web of Science, SciFinder, Reaxys, PubMed, IEEE Explore and Engineering Index. At least one author in each of the publications has the CHBC department as its affiliation. It includes a table summarizing the research. The listing is organized according to type of publications within specific years.

Extended Planar Defects Of Oxygen Vacancies In Ferroelectric Batio3 And Impact On Ferroelectricity, Shaohui Qiu, Huaxiang Fu

Physics Faculty Publications and Presentations

Extended defects of vacancies in ferroelectrics (FE), where vacancies spread over an extended space, are of critical importance in terms of understanding the long-standing problems such as polarization fatigue and aging. However, extended defects in FEs are poorly understood. Here we investigate the extended planar oxygen vacancies in ferroelectric BaTiO₃ using density functional theory and the modern theory of polarization. Oxygen vacancies of different charge states, namely V ²⁺_O , V ¹⁺_O , and V ⁰_O , are studied. We obtain interesting results such as: (i) The formation energy of planar V ²⁺_O vacancies can …

Flexible And Sewable Electrode Based On Ni-Co@Pani-Salphen Composite-Coated On Textiles For Wearable Supercapacitor, Touba Rezaee Adriyani, Ali A. Ensafi, B. Rezaei

Chemistry & Biochemistry Faculty Publications and Presentations

Flexible electrodes with high deformability and energy density are critical for electronic textiles. The key factor for achieving high-performance supercapacitors with superior power and energy density is the evaluation of materials that exhibit exceptional capacitive performance. Herein, we have prepared Ni-Co nanoparticles at the surface of polyaniline-salphen (Ni-Co@PS). Then, followed by casting Ni-Co@PS on a conductive carbon cloth (CC) as a substrate through a facile in-situ polymerization strategy. The morphologies of Ni-Co@PS composite were characterized by different methods such as FE-SEM, XPS, XRD, BET, and electrochemical methods. This nanocomposite showed high tolerability and a large surface area with excellent behavior …

Observed And Modeled Moulin Heads In The Pâkitsoq Region Of Greenland Suggest Subglacial Channel Network Effects, Celia Trunz, Kristin Poinar, Lauren C. Andrews, Matthew D. Covington, Jessica Mejia, Jason Gulley, Victoria Siegel

Geosciences Faculty Publications and Presentations

In the ablation zone of land-terminating areas of the Greenland Ice Sheet, water pressures at the bed control seasonal and daily ice motion variability. During the melt season, large amounts of surface meltwater access the bed through moulins, which sustain an efficient channelized subglacial system. Water pressure within these subglacial channels can be inferred by measuring the hydraulic head within moulins. However, moulin head data are rare, and subglacial hydrology models that simulate water pressure fluctuations require water storage in moulins or subglacial channels. Neither the volume nor the location of such water storage is currently well constrained. Here, we …

Toward An Economic Reformulation Of Public Pension Funding, Robert Costrell, Josh B. Mcgee

Education Reform Faculty and Graduate Students Publications

We propose an economic reformulation of contribution policy integrating: (1) formalization of sustainability as the steady-state contribution rate, incorporating both the expected return on risky assets and a low-risk discount rate for liabilities; (2) derivation of contribution adjustment policies required for convergence toward the target funded ratio and contribution rate; and (3) a stylized optimization framework for simultaneous determination of the target portfolio return and funded ratio. This analysis provides new theoretical insights into the basis for pre-funding vs. pay-as-you-go, resting on the convexity of the long-run risk–return relationship, and also potentially practical guidelines for contribution policy.

Educational Outcomes Of Recess In Elementary School Children: A Mixed-Methods Systematic Review, Erin K. Howie, Kristi L. Perryman, Joseph Moretta, Laura Cameron

Health, Human Performance and Recreation Faculty Publications and Presentations

Background

Recess provides a key physical activity opportunity for students in school, yet a wide range of recess requirements exist. To design optimal recess policies, the effect of recess on students’ educational outcomes must be better understood. Therefore, the purpose of this mixed-method systematic review is to identify and systematically evaluate research on the effects of recess on student educational outcomes, including behavior, cognitive performance and academic achievement.

Methods

A systematic search of the literature in ERIC (EBSCO), ProQuest Central, PsycINFO, Teacher Reference Center, MEDLINE Complete (EBSCO), and CINAHL Complete was performed through September 2022. Data was extracted from quantitative …

Quantum Criticality At Cryogenic Melting Of Polar Bubble Lattices, Wei Luo, Alireza Akbarzadeh, Yousra Nahas, Sergei Prokhorenko, Laurent Bellaiche

Physics Faculty Publications and Presentations

Quantum fluctuations (QFs) caused by zero-point phonon vibrations (ZPPVs) are known to prevent the occurrence of polar phases in bulk incipient ferroelectrics down to 0 K. On the other hand, little is known about the effects of QFs on the recently discovered topological patterns in ferroelectric nanostructures. Here, by using an atomistic effective Hamiltonian within classical Monte Carlo (CMC) and path integral quantum Monte Carlo (PI-QMC), we unveil how QFs affect the topology of several dipolar phases in ultrathin Pb(Zr_0.4Ti_0.6)O₃ (PZT) films. In particular, our PI-QMC simulations show that the ZPPVs do not suppress polar …

The High Energy X-Ray Probe: Resolved X-Ray Populations In Extragalactic Environments, Bret D. Lehmer, Kristen Garofali, Breanna A. Binder, Francesca Fornasini, Neven Vulic, Andreas Zezas, Ann Hornschemeier, Margaret Lazzarini, Hannah Moon, Toni Venters, Daniel Wik, Mihoko Yukita, Matteo Bachetti, Javier A. Garcia, Brian Grefenstette, Kristin Madsen, Kaya Mori, Daniel Stern

Physics Faculty Publications and Presentations

We construct simulated galaxy data sets based on the High Energy X-ray Probe (HEX-P) mission concept to demonstrate the significant advances in galaxy science that will be yielded by the HEX-P observatory. The combination of high spatial resolution imaging (FWHM), broad spectral coverage (0.2–80 keV), and sensitivity superior to current facilities (e.g., XMM-Newton and NuSTAR) will enable HEX-P to detect hard (4–25 keV) X-ray emission from resolved point-source populations within ∼800 galaxies and integrated emission from ∼6,000 galaxies out to 100 Mpc. These galaxies cover wide ranges of galaxy types (e.g., normal, starburst, and passive galaxies) and properties (e.g., metallicities …

Using Post-Season Tissue Nitrogen Concentrations To Predict Adequacy Of In-Season Nitrogen Management, Kyle Hoegenauer, Trenton Roberts, Carrie Ortel, Jarrod Hardke, Mike Richardson, Mike Daniels

Crop, Soil and Environmental Sciences Faculty Publications and Presentations

High-yielding mechanized rice production requires large amounts of nitrogen (N) fertilizer, which can be particularly costly to producers when applied in excess. The development of a tissue test to detect overapplication of N to rice is needed. Nitrogen response trials arranged in a randomized complete block design were established to identify a critical concentration threshold for a tissue test to detect excess N availability. Rice stalk samples were collected from 0 to 20 cm above the soil within 5 days of harvest and analyzed for NO₃ −-N concentration. Two models were fit to the data to represent rice grain …

High-Growth Elementary Schools In Arkansas Based On Performance On The Act Aspire Examinations, Sarah C. Mckenzie

Arkansas Education Reports

This section highlights elementary schools across the state whose students demonstrated high growth on the Arkansas ACT Aspire exams. The ACT Aspire was administered to students in grades 3 through 10 in April 2023 in Math and ELA courses which include English, Writing, and Reading. Each table in this section presents the Top 20 schools for the noted subject area and school level. In addition, these tables include the region in which the schools are located, the grades served at the school, the weighted achievement score, and the content growth score in that particular subject. The level of the schools, …

Genetic Architecture Of Soybean Tolerance To Off-Target Dicamba, Caio Canella Vieira, Jing Zhou, Diego Jarquin, Jiangfeng Zhou, Brian Diers, Dean E. Riechers, Henry T. Nguyen, Grover Shannon

Crop, Soil and Environmental Sciences Faculty Publications and Presentations

The adoption of dicamba-tolerant (DT) soybean in the United States resulted in extensive off-target dicamba damage to non-DT vegetation across soybean-producing states. Although soybeans are highly sensitive to dicamba, the intensity of observed symptoms and yield losses are affected by the genetic background of genotypes. Thus, the objective of this study was to detect novel marker-trait associations and expand on previously identified genomic regions related to soybean response to off-target dicamba. A total of 551 non-DT advanced breeding lines derived from 232 unique bi-parental populations were phenotyped for off-target dicamba across nine environments for three years. Breeding lines were genotyped …

Snapshot Of The Research Publications From The Department Of Biological Sciences, University Of Arkansas, 2019-2022, Lutishoor Salisbury, Jeremy Smith

University Libraries Faculty Publications and Presentations

This report provides a snapshot of the research publications for the Department of Biological Sciences for a four-year period.

It includes tables identifying the types of publications, the research collaboration between faculty and students (graduates and undergraduates); the JCR ranking of the journals in which they published and a listing of their publications, etc.

Editorial: Parasitism: The Good, The Bad And The Ugly, Marco A. Juarez-Estrada, Danielle Graham, Xochitl Hernandez-Velasco, Guillermo Tellez-Isaias

Poultry Science Faculty Publications and Presentations

Editorial on the Research Topic

Parasitism: the good, the bad and the ugly