Digital Commons Network^™

North Korean Cyber Attacks And Policy Responses: An Interdisciplinary Theoretical Framework, Jeeseon Hwang, Kyung-Shick Choi

International Journal of Cybersecurity Intelligence & Cybercrime

No abstract provided.

Effectiveness Of Softening Agents For Enhancing Properties Of Asphalt Mixes With High Rap Contents, Zahid Hossain, Ashraf Elsayed, Sumon Roy

Publications

A high percentage of reclaimed asphalt pavement (RAP) in new asphalt concrete can lead to developing premature failure of asphalt pavements due to fatigue or low-temperature cracking. The use of softening agents in asphalt binders can resolve these problems. The aim of this study is to evaluate the effectiveness of softening agents for enhancing the properties of asphalt mixes with high RAP contents. Two waste products, namely, waste cooking oil (WCO), and engine bottom oil (EBO) along with a commercially produced rejuvenator were investigated in this study. The following three types of Performance Grade (PG) binders, each collected from two …

Feasibility Assessment Of Warm Mix Asphalt In Arkansas, Zahid Hossain, Ashraf Elsayed, Mohammad Najmush Sakib Oyan

Publications

The future of Warm Mix Asphalt (WMA) technologies is promising in the U.S. However, the Arkansas Department of Transportation (ARDOT) does not have any specific guidelines to implement them in the field. This research aims to provide necessary baseline data for WMA as a proof of concept. In this study, three ARDOT approved Performance Grade (PG) binders namely PG 64-22, PG 70-22, and PG 76-22 were investigated. Each of these binders was obtained from two different sources. They were modified by varying doses of four selected additives: Sasobit®, Advera®, Evotherm®, and Rediset®. Additionally, four different types of aggregates (sandstone, limestone, …

Development Of Cost-Effective High-Modulus Asphalt Concrete (Hmac) Mixtures Using Crumb Rubber And Local Construction Materials In Louisiana, Momen R. Mousa, Marwa Hassan, Ibrahim A.I.E Elnaml

Publications

One of the emerging solutions to enhance the durability of asphalt pavements is the use of a French asphalt mix known as “High-Modulus Asphalt Concrete (HMAC).” This mix uses a hard asphalt binder, high binder content (about 6%), and low air voids content as compared to Superpave mixtures. The key objective of this study was to develop a cost-effective HMAC mixture using crumb rubber and local materials in Louisiana. To achieve this objective, four HMAC mixtures were prepared using two asphalt binders (PG 82-22 and PG 76-22 plus 10% crumb rubber) and two Reclaimed Asphalt Pavement (RAP) contents (20% and …

Evaluation Of Alternative Sources Of Supplementary Cementitious Materials (Scms) For Concrete Materials In Transportation Infrastructure, Gabriel A. Arce, Miladin Radovic, Zahid Hossain, Marwa Hassan, Sujata Subedi

Publications

Fly ash is the most utilized supplementary cementitious material (SCM) in the US. Nonetheless, rapid decline in coal-fired power generation threatens its supply. The objective of this study was to evaluate alternative SCMs for concrete transportation infrastructure in Region 6. SCMs investigated included reclaimed fly ash (RFA), reclaimed ground bottom ash (GBA), metakaolin (MK), and conventional Class F fly ash (FA) as a reference. SCMs were characterized and the fresh and hardened properties of concrete incorporating different dosages (i.e., 10, 20, and 30% cement replacement by mass) of the individual SCMs (i.e., binary systems) and blended SCM systems of RFA-MK …

Resilient 3d-Printed Infrastructure With Engineered Cementitious Composites (Ecc), Maryam Hojati

Publications

Conventional construction of reinforced concrete structures is slow, labor-intensive, and expensive. 3D printing holds great potential to assist engineers and architects in constructing fast and economical yet complex representational infrastructures. One of the most significant barriers to the broader adoption of concrete 3D printing in civil infrastructure is the difficulty of providing printed structural components with reinforcement to achieve sound structural performance under different loading conditions. Hence, it is essential to design concrete that can be utilized as a rebar-free material by considering strength and ductility. Recently, the development of Engineered Cementitious Composites (ECC) has neared the possibility to achieve …

Evaluation Of Sustainable And Environmentally Friendly Stabilization Of Cohesionless Sandy Soil For Transportation Infrastructure, Miladin Radovic, Anand Puppala, Surya Sarat Chandra Congress, Jungyeon Jang, Oscar Huang

Publications

Ordinary Portland cement (OPC) is generally used to stabilize cohesionless sandy soils that are often found in coastal areas. Due to its high carbon footprint, many studies are being conducted to identify a suitable green alternative for stabilizing cohesionless soils. Previous studies have shown that partially replacing OPC with waste materials such as nano-silica and coal waste reduces the overall carbon footprint without significantly impacting the performance. Geopolymer (GP) received a lot of attention in the past few decades owing to its similar properties to that of OPC yet with a lower carbon footprint. This study investigated the feasibility of …

An Automated System For Inspecting Rock Faces And Detecting Potential Rock Falls Using Machine Learning, John Stormont, Fernando Moreu, Amir Bagherieh, Roya Nasimi, Solomon Atcitty

Publications

Rockfall is a hazard in mountainous areas threatening infrastructure and human lives. Rockfall hazards are often mitigated by manual inspections using pry bars. The inspector must access the rock face, hit the rock surface, detect, and remove the loose rocks. This method is very labor demanding, unsafe, and challenging. This research presents a method that automatize the inspection of rock blocks that are prone to rockfall events. A robot is developed to replace the manual hammer tap process and collect the sound data remotely; subsequently, the sound signal is used to identify different types of the discontinuity in rocks in …

Resource Guide For State Dot’S Maintenance Equipment Fleet Management Decisions, Yongwei Shan, Samir Ahmed, Lei Qiao

Publications

This research created a guide for state Departments of Transportation fleet management on utilizing equipment fleet management system data to make informed fleet management decisions. The research team took the historical equipment fleet data from the Oklahoma Department of Transportation and developed workflows, algorithms, and examples to demonstrate the use of historical equipment data for equipment decisions. Specifically, the research team demonstrated 1) the use of life cycle analysis and dynamic programming models for equipment replacement decisions; 2) developed algorithms to calculate equipment rental rates that can be used by the Department to forecast and allocate equipment operational budget among …

Preventing Struck-By Hazards: Defying Risk-Habituation Via Virtual Accident Simulation, Changbum Ahn

Publications

Repeated exposure to struck-by hazards in road work zones generates workers’ habituation to risks related to those hazards, a key contributor to accidents in road work zones. Thus, analyzing the development of risk habituation and providing proper intervention are crucial to preventing accidents in road work zones. In this context, this study employs a virtual reality (VR) environment as a behavioral intervention tool to investigate its effect on mitigating a decline in workers’ vigilance with habituation to hazards in workplaces. A virtual environment that simulates a road maintenance task was developed and used to repeatedly expose subjects to struck-by hazards …

Bridge Cracks Monitoring: Detection, Measurement, And Comparison Using Augmented Reality, Fernando Moreu, Kaveh Malek

Publications

Crack occurrence and propagation are among critical factors that affect the performance and lifespan of civil infrastructures such as bridges. Consequently, numerous crack detection and measurement methods have been proposed and developed in the recent decades in the areas of Structural Health Monitoring and non-destructive testing. Many novel technologies have emerged with the potential to overcome the limitations of the presented techniques of crack detection and characterization. Crack detection and characterization method used in this research lies in supplementing human visual inspection capabilities in a systematic manner through an appropriate level of automation. The Augmented Reality (AR) tool developed in …

Maintenance And Restriping Strategies For Pavement Markings On Asphalt Pavements In Louisiana, Momen R. Mousa, Marwa Hassan

Publications

In Louisiana, most districts restripe their roadways using waterborne paints every other year; this strategy is questionable in terms of efficiency and economy. Meanwhile, previous studies showed substantial variability in the paint service life throughout the United States ranging between 0.25 and 6.2 years. Shortcomings in modeling the retroreflectivity of waterborne paints appear to significantly contribute to these variations as several studies predicted these values using degradation curves with a coefficient of determination (R2) as low as 0.1. Therefore, the objective of this study was to (i) develop new cost-effective restriping strategies using 4-inch (15-mil thickness) and 6-inch (25-mil thickness) …

Determination Of The Optimal Parameters For Self-Healing Efficiency Of Encapsulated Bacteria In Concrete Simulated Subtropical Climate, Momen R. Mousa, Marwa Hassan, Gabriel Andres Arce Amador, Ricardo Hungria, Andrea Gavilanes, Omar Kamal

Publications

Concrete is a remarkable construction material. However, its low tensile strength makes it prone to cracking, which negatively affects its durability. To address this issue, bacterial concrete has been implemented as a self-healing alternative due to its capability to seal microcracks through microbial-induced calcium carbonate precipitation (MICCP). In this study, a bacterial strain (i.e, Bacillus Pseudiformus) was encapsulated through three different methods: encapsulation through hydrogel beads, vacuum impregnation on lightweight aggregates, and attachment to cellulose nanocrystals. Furthermore, three precursor types were used, magnesium acetate, calcium lactate, and sodium lactate were implemented. Compressive strength tests and flexural strength tests were performed …

Development Of A Multi-Level Dynamic Model To Measure The Resilience Level Of Transportation Infrastructure Networks, Sharareh Kermanshachi, Jianling Li, Thahomina Jahan Nipa

Publications

The recent increase in disasters is making the largest critical infrastructure system namely the transportation infrastructure system susceptible to unexpected damage. Discontinuation of services provided by transportation infrastructures will create significant societal, economic, and collateral damages. Therefore, this study aims to identify dimensions to measure the resilience of the transportation infrastructures. This study also aims to develop a model to measure the resilience of the transportation infrastructures resilience. To fulfill the aims of this study, a questionnaire was developed which was supported by a comprehensive literature review. 92 valid responses were received and analyzed qualitatively and quantitatively. Statistically significant variables …

Alfred Russel Wallace Notes 18: Wallace On The Balance Of Nature, Charles H. Smith

Faculty/Staff Personal Papers

Alfred Russel Wallace (1823−1913) had a unique perspective on the ‘balance of nature’: he avoided classical thoughts on the subject, but nevertheless seems to have adopted elements of the ‘balance’ concept while acknowledging that irreversible change occurs at both the biological and environmental levels. Wallace’s position can be understood from his grounding in Humboldtian ‘equilibrium of forces’ thinking, and his turn toward ‘final causes’-based interpretations.

Incorporating Machine Learning Algorithm In Modified Quality By Design Approach On Simulated Penicillin Fermentation Dataset, Shengting Xu

Dissertations and Theses (Open Access)

For this thesis, we utilized random forest (RF) algorithm in combination with Quality by Design (QbD) in simulated commercial-scale penicillin production dataset. The RF algorithm was primarily used in the selection of critical process parameters (CPPs). In this analysis, the primary critical quality attributes (CQA) was set to be the final penicillin yield. After the CPPs were selected by the RF algorithm, we would propose design of experiment (DoE) by using fractional factorial design to establish mathematical relationships between CPPs and CQAs. Among the five RF models, we chose two models before proceeding to the DoE step. One using the …

Secrets, Lies, And Lessons From The Theranos Scandal, Lauren Rogal

UC Law Journal

Theranos, Inc., the unicorn startup blood-testing corporation, was ultimately laid low by a former employee whistleblower. The experience of that whistleblower during and after her employment illuminates detrimental secrecy practices within the startup sector, as well as legal and practical barriers to corporate accountability. Theranos sought to avoid exposure by cultivating an environment of secrecy and intimidation, and by aggressively extracting and enforcing nondisclosure agreements. The legal landscape for whistleblowers facilitated this strategy: while whistleblowing employees enjoyed certain protections under anti-retaliation statutes, trade secrets statutes, and common law contract principles, these protections were neither readily accessible nor certain. This Article …

Ground Control Point Assessment For Suas-Based Sfm Photogrammetry, Bailey Dianne Wolf

Graduate Theses/Dissertations

The use of small Unmanned Aerial Systems (sUAS) in combination with Structure from Motion (SfM) photogrammetry is an evolving tool for geoscientists. SfM photogrammetry allows for rapid acquisition of the data that is required to create orthophotos and Digital Surface Models (DSMs) for a variety of field applications. Ground Control Points (GCPs) are used to reconstruct the DSM and evaluate the accuracy of aerial imagery collected from sUAS. When acquiring data for SfM photogrammetry, GCPs are required for spatial referencing. However, questions remain open regarding the effect of methodological techniques on the precision and accuracy of the resulting DSMs. This …

Predicting Severity Of Traumatic Brain Injury: A Residual Learning Model From Magnetic Resonance Images, Dacosta Yeboah

Graduate Theses/Dissertations

One of the most significant frontiers for computational scientists is the engineering of human healthcare delivery based on intelligent analysis of health data. In a variety of neurological disorders such as Traumatic Brain Injury (TBI), neuro-imaging information plays a crucial role in the decision-making regarding patient care and as a potential prognostic marker for outcome. TBI is a heterogeneous neurological disorder. Due to the economic burdens of the disorder, sorting out this heterogeneity could provide more insights and better understanding of TBI recovery trajectories, thus improving overall diagnosis and treatment options. Magnetic Resonance Imaging (MRI) is a non-invasive technique that …

Development Of Eam And Rf-Meam Interatomic Potential For Zirconium Diboride, Bikash Timalsina

Graduate Theses/Dissertations

Embedded Atom Method (EAM) and Modified-EAM (MEAM) interatomic potentials were developed for zirconium diboride (ZrB₂). The EAM and “Reference Free” (RF) version of the Modified Embedded Atom Method (RFMEAM) potentials have been fitted by utilizing Density Functional Theory (DFT)-based datasets including lattice deformations and high-temperature ab-initio molecular dynamics (AIMD) simulation results. The occupancies of phonons for acoustic phonon modes from the density functional theory calculation shows that these modes of vibration, mostly due to heavier mass element (Zr), which occur below 8.711 THz, while a slight underestimation to that of DFT calculation predicted by EAM below 8.439 THz …

3d Printing Of Custom Sample Holders As A Responsive And Cost-Effective Method Of Sample Holder Generation For Electron Microscopy., A Strachan, D Haspel, N Stephen

School of Engineering, Computing and Mathematics

No abstract provided.

Active Travel For Children And Youth: Lessons From Active Routes To Schools North Carolina, Leah Ferguson

Electronic Theses and Dissertations

This Integrated Learning Experience (ILE) investigates literature regarding the impact of national Safe Routes to School (SRTS) programs and takes a deeper dive into the lessons that can be learned from North Carolina’s Active Routes to School (NC ARTS) programs through an analysis of data collected from 2007 to 2019. This report is focused on understanding the relationship between and among variables included in the Six Es of SRTS framework: Education, Engineering, Encouragement, Enforcement, Equity, and Evaluation. This investigation provides insight that extends understanding of parental comfort and engagement with these programs. A unique theoretical model was developed as were …

Shared Decision-Making For Contraceptive Counseling Among Women Seeking Services At Safety Net Clinics In South Carolina And Alabama, Dumisa M. Nyarambi

Electronic Theses and Dissertations

Shared decision-making (SDM) for contraceptive counseling and method initiation is a hallmark of patient-centered care; SDM is associated with patient satisfaction, method continuation, and the prevention of pregnancy and short inter-pregnancy intervals. To achieve a high-quality experience for women Person-centered approach to counseling is the preferred approach to achieve SDM. Demographic factors and women’s perceptions of their providers have been linked to decision-making. Literature is lacking on SDM practices in safety net clinics, particularly in local health departments. Exploring these constructs is important to inform practices and policies for family planning. This research aimed to examine: 1) the influence of …

Perceptions Of Resilience-Informed Education In Postsecondary Instructors, Chelsea L. Robertson

Electronic Theses and Dissertations

Many studies have noted the detrimental impact adverse childhood experiences (ACEs) can have on individuals’ developmental trajectories and, as a result, the utilization of trauma-informed practices has been of increasing interest within the field of education. Most research on trauma-informed pedagogy is derived from samples of children in grades K-12, whereas research on trauma-informed teaching practices within higher education is comparatively scarce. The specific aims of the current investigation are two-fold. The first aim is to explore the effect of postsecondary instructors’ disciplinary specialization (i.e., person-thing orientation) on their receptivity to compassionate teaching practices. The second aim is to implement …

Non-Invasive In-Vitro Glucose Monitoring Using Optical Sensor And Machine Learning Techniques For Diabetes Applications, Maryamsadat Shokrekhodaei

Open Access Theses & Dissertations

Diabetes is a major public health challenge affecting more than 451 million people. Physiological and experimental factors influence the accuracy of non-invasive glucose monitoring, and these need to be addressed before replacing the finger prick method with a non-invasive glucose measurement technique. Also, the suitable employment of machine learning techniques on experimental data can significantly improve the accuracy of glucose predictions.

This work includes the design, development, testing and data analysis of an optical based sensor for glucose measurements. The feasibility of non-invasive measurement of glucose within aqueous solutions that assimilate the composition of human blood plasma is investigated. The …

Towards Reinforcement Learning Driven Mesh Adaptivity For Second Order Elliptic Problems, Augustine Twumasi

Open Access Theses & Dissertations

Adaptive mesh refinement techniques have become an indispensable tool in achieving accurate and efficiently computed solutions to problems which require impractically fine uniform meshes to obtain an accurate approximation. The adaptive algorithm involves a recursive application of SOLVE-ESTIMATE-MARK-REFINE steps where in particular the step `ESTIMATE' involves computing a posteriori error estimator based on only the numerical solution and the data of the problem. Over the years, several a posteriori error estimators have been developed and successfully applied but often times, the choice of estimator is ill suited for the problem at hand. In this research, we present two estimators namely …

Restoring Biogeochemical Properties In Drylands And Exploring Functional Roles Of Biological Soil Crust, Kristina Young

Open Access Theses & Dissertations

Degradation in dryland regions is a persistent and accelerating problem. Though the mechanisms that initiate and maintain dryland degradation have been well studied, restoring productivity and function to degraded dryland ecosystems remains difficult. Here, I present three chapters that address gaps in our understanding of dryland functions and our ability to restore them. I begin by examining how dryland restoration research has addressed altered biogeochemical cycling in drylands and how to expand current understandings of dryland biogeochemistry into restoration. I then present two chapters that explore mechanistic and quantitative understandings of the contribution of biocrusts to soil nutrient cycling both …

Modeling The Spatiotemporal Dynamics Of Active Regions On The Sun Using Deep Neural Networks, Godwill Amankwa

Open Access Theses & Dissertations

Solar active regions are areas on the Sun's surface that have especially strong magnetic fields. Several phenomena that can have significant negative effects on technology and subsequently on human life, such as solar flares and coronal mass ejections (CMEs), are often associated with active regions.Since the physical phenomena underlying the evolution of active regions are still poorly understood, the accurate prediction of solar flares and coronal mass ejections remains an open problem.

Extracting insights from the available datasets of solar activity that can lead to a better understanding of solar active regions has been an important research goal at the …

Associations Between Exposure To Air Pollution After A Dust Event And Hospitalizations., Estrella De Jesus Herrera-Molina

Open Access Theses & Dissertations

The Southwestern region has been identified as one of the most persistent dust producing regions of North America. Exposure to inhalable particulate matter (PM10) originating from desertic landscape during dust events/dust exposures (DEs) can reach hazardous levels. El Paso, Texas’s ambient air has reached hazardous levels of PM10 above 4000 μg/m3 with near zero visibility due to these natural events. There are very few prior studies in the southwestern United States pertaining to the associations between exposure to atmospheric aerosol after DEs and hospitalizations, nor are there many epidemiological studies globally in dusty environments where most of the atmospheric aerosol …

Evaluation Of Electrodialysis Desalination Performance Of Novel And Conventional Ion Exchange Membranes, Ahm Golam Hyder

Open Access Theses & Dissertations

It was revealed from relevant recent literature that the electrodialysis (ED) desalination performance of commercial and laboratory-made ion exchange membranes (IEMs) had been studied previously but not in a systematic way so that the planners, designers, and engineers can evaluate a trade-off in selecting the suitable IEMs and optimum ED experimental conditions for their desired outcomes such as high ion selectivity, high salinity removal, high water recovery, low energy consumption, or low water transport. Furthermore, the existing conventional and laboratory-made IEMs reported previously showed various technical and economical limitations with respect to permeability, permselectivity, ion selectivity, electrical resistance, stability (mechanical, …