Engineering Commons^™

Cessation And Resumption Of Elective Neurointerventional Procedures During The Coronavirus Disease 2019 Pandemic And Future Pandemics, Tim W. Malisch, Sameer A. Ansari, Gary R. Duckwiler, Kyle M. Fargen, Steven W. Hetts, Franklin A. Marden, Athos Patsalides, Clemens M. Schirmer, Allan Brook, Justin F. Fraser

Neurosurgery Faculty Publications

At the time of this writing, the coronavirus disease 2019 pandemic continues to be a global threat, disrupting usual processes, and protocols for delivering health care around the globe. There have been significant regional and national differences in the scope and timing of these disruptions. Many hospitals were forced to temporarily halt elective neurointerventional procedures with the first wave of the pandemic in the spring of 2020, in order to prioritize allocation of resources for acutely ill patients and also to minimize coronavirus disease 2019 transmission risks to non-acute patients, their families, and health care workers. This temporary moratorium on …

Don't Bite The Bait: Phishing Attack For Internet Banking (E-Banking), Ilker Kara

Journal of Digital Forensics, Security and Law

Phishing attacks are based on obtaining desired information from users quickly and easily with the help of misdirecting, panicking, curiosity, or excitement. Most of the phishing web sites are designed on internet banking(e-banking) and the attackers can acquire financial information of misled users with the tactics and discourses they develop. Despite the increase of prevention techniques against phishing attacks day by day, an effective solution could not be found for this issue due to the human factor. Because of this reason, real phishing attack studies are essential to study and analyze the attackers’ attack techniques and strategies. This study focused …

Driver Perceptions On Taxi-Sharing And Dynamic Pricing In Taxi Services: Evidence From Athens, Greece., Christina Milioti, Konstantinos Kepaptsoglou, Konstantinos Kouretas, Eleni Vlahogianni

Journal of Public Transportation

The taxi industry has changed dramatically during the last decade, as ride-sourcing applications, ride-sharing and alternative pricing schemes have emerged, either as complementing or competitive services and strategies. After some years of familiarity with such trends, it is interesting to explore where the taxi industry stands with respect to possible service innovations. This paper explores behavioral patterns of drivers, focusing on issues such as their preferred way of conducting business, and their views on introducing taxi-sharing and dynamic pricing. Data collected from a face-to-face questionnaire survey in Athens, Greece are exploited, and appropriate econometric models are developed for the purposes …

An Efficient Track-Scale Model For Laser Powder Bed Fusion Additive Manufacturing: Part 1- Thermal Model, Reza Tangestani, Trevor Sabiston, Apratim Chsktsborty, Waqas Muhammad, Lang Yuan, Étienne Martin

Faculty Publications

This is the first of two manuscripts that presents a computationally efficient full field deterministic model for laser powder bed fusion (LPBF). A new Hybrid Line (HL) heat input model integrates an exponentially decaying (ED) heat input over a portion of a laser path to significantly reduce the computational time. Experimentally measured properties of the high gamma prime nickel-based superalloy RENÉ 65 are implemented in the model to predict the in-process temperature distribution, stresses, and distortions. The model accounts for specific properties of the material as different phases. The first manuscript presents the HL heat transfer model, which is compared …

Learning State-Dependent Sensor Measurement Models To Improve Robot Localization Accuracy, Troi André Williams

USF Tampa Graduate Theses and Dissertations

This dissertation proposes a novel method called state-dependent sensor measurement models (SDSMMs). Such models dynamically predict the state-dependent bias and uncertainty of sensor measurements, ultimately improving fundamental robot tasks such as localization. In our first investigation, we introduced the state-dependent sensor measurement model framework, described their properties, stated the input and output of these models, and described how to train them. We also explained how to integrate such models with an Extended Kalman Filter and a Particle Filter, two popular robot state estimation algorithms. We validated the proposed framework through a series of localization tasks. The results showed that our …

Metal Fatigue And Crack Propagation Using Thermodynamic/Thermoelectric Approach, Behnam Hajshirmohammadi

LSU Doctoral Dissertations

The present dissertation concentrates on the fatigue life of metals and fatigue crack growth (FCG). The basic concept of fatigue thermodynamics is used for this purpose. With the application of thermoelectricity, a method is developed on the basis of fracture fatigue entropy (FFE) for the rapid estimation of the fatigue life of components. To this end, thermoelectric signals captured from a specimen during cyclic loading are analyzed, and a procedure is proposed for the calculation of fatigue life based on the thermoelectric signals in the beginning and the steady-state zone of fatigue. Temperature gradient and electric potential gradients in metals …

Moisture Affinity Of Hdpe/Phase-Change Material Composites For Thermal Energy Storage Applications, Sandra K. Boetcher, Thomas B. Freeman, Rafael M. Rodriguez, Kashif Nawaz

Publications

Moisture adsorption can degrade the structural integrity of thermal energy storage devices and can negatively impact the capacity and charging/discharging behavior. Steady-state and transient experiments are conducted at various operating temperatures to evaluate the moisture affinity of organic phase-change material (PCM) shape stabilized with high-density polyethylene (HDPE).

Effectiveness Assessment Of The Search-Based Statistical Structural Testing, Yang Shi, Xiaoyu Song, Marek A. Perkowski, Fu Li

Electrical and Computer Engineering Faculty Publications and Presentations

Search-based statistical structural testing (SBSST) is a promising technique that uses automated search to construct input distributions for statistical structural testing. It has been proved that a simple search algorithm, for example, the hill-climber is able to optimize an input distribution. However, due to the noisy fitness estimation of the minimum triggering probability among all cover elements (Tri-Low-Bound), the existing approach does not show a satisfactory efficiency. Constructing input distributions to satisfy the Tri-Low-Bound criterion requires an extensive computation time. Tri-Low-Bound is considered a strong criterion, and it is demonstrated to sustain a high fault-detecting ability. This article tries to …

Novel Quantum Algorithms To Minimize Switching Functions Based On Graph Partitions, Peng Gao, Marek A. Perkowski, Yiwei Li, Xiaoyu Song

Electrical and Computer Engineering Faculty Publications and Presentations

After Google reported its realization of quantum supremacy, Solving the classical problems with quantum computing is becoming a valuable research topic. Switching function minimization is an important problem in Electronic Design Automation (EDA) and logic synthesis, most of the solutions are based on heuristic algorithms with a classical computer, it is a good practice to solve this problem with a quantum processer. In this paper, we introduce a new hybrid classic quantum algorithm using Grover’s algorithm and symmetric functions to minimize small Disjoint Sum of Product (DSOP) and Sum of Product (SOP) for Boolean switching functions. Our method is based …

Optically Active Selenium Vacancies In Baga4Se7 Crystals, Brian C. Holloway, Timothy D. Gustafson, Christopher A. Lenyk, Nancy C. Giles, Kevin T. Zawilski, Peter G. Schunemann, Kent L. Averett, Larry E. Halliburton

Faculty Publications

Barium gallium selenide (BaGa₄Se₇) is a recently developed nonlinear optical material with a transmission window extending from 470 nm to 17 μm. A primary application of these crystals is the production of tunable mid-infrared laser beams via optical parametric oscillation. Unintentional point defects, such as selenium vacancies, cation vacancies (barium and/or gallium), and trace amounts of transition-metal ions, are present in BaGa₄Se₇ crystals and may adversely affect device performance. Electron paramagnetic resonance (EPR) and optical absorption are used to identify and characterize these defects. Five distinct EPR spectra, each representing an electron …

An Assessment And Exploration Of Recent Methodological Advances In Safety Data Analysis, Suryaprasanna Kumar Balusu

USF Tampa Graduate Theses and Dissertations

The injury severity and frequency of traffic crashes can be further reduced by implementing appropriate traffic safety measures. Several advanced methodologies have been developed in the recent decades to more accurately identify the factors affecting road safety. Such methodologies have helped policy makers formulate appropriate safety measures directed toward increasing seatbelt and helmet use, reducing speed limits in school zones, implementing adolescent driver programs, and so on. However, each methodological approach has its own strengths and weakness and could lead to different inferences. This dissertation assesses and explores a number of recently developed methodologies and their application to traffic safety …

Fabrication Of Oxide-Based Memristors For Neural Networks, Jamison E. Wagner

Electrical and Computer Engineering ETDs

This thesis discusses what a memristor is, how it is hypothesized to work and the fabrication work undertaken with hafnia and titania-based ultrathin oxide films. In addition, the electrical tests utilized to characterize the physical performance of the memristors including but not limited to, their IV hysteresis responses, yield rates and overall reliability. The results and discussion of this work are aimed at better understanding how fabrication of memristive devices can be further improved for future work.

Intelligent Internet Of Things Frameworks For Smart City Safety, Dimitrios Sikeridis

Electrical and Computer Engineering ETDs

The emerging Smart City ecosystem consists of a vast edge network of Internet of Things (IoT) devices that continuously interact with mobile devices carried by its citizens. In this setting, the IoT infrastructure, apart from the main communications facilitator, acts as a crowdsourcing mechanism that collects massive amounts of user data, and can support public safety applications for the Smart City. In this thesis, we design and analyze learning mechanisms that extract intelligence from crowd interactions with the wireless IoT infrastructure, and optimize its energy efficiency while operating as a public safety network. First, we deploy a multi-story facility testbed …

Intelligent Sensors For Sustainable Food And Drink Manufacturing, Nicholas J. Watson, Alexander L. Bowler, Ahmed Rady, Oliver J. Fisher, Alessandro Simeone, Josep Escrig, Elliot Woolley, Akinbode A. Adedeji

Biosystems and Agricultural Engineering Faculty Publications

Food and drink is the largest manufacturing sector worldwide and has significant environmental impact in terms of resource use, emissions, and waste. However, food and drink manufacturers are restricted in addressing these issues due to the tight profit margins they operate within. The advances of two industrial digital technologies, sensors and machine learning, present manufacturers with affordable methods to collect and analyse manufacturing data and enable enhanced, evidence-based decision making. These technologies will enable manufacturers to reduce their environmental impact by making processes more flexible and efficient in terms of how they manage their resources. In this article, a methodology …

Graphene Flake Self-Assembly Enhancement Via Stretchable Platforms And External Mechanical Stimuli, Harrison A. Loh, Claudio Marchi, Luca Magagnin, Konstantinos A. Sierros

Faculty & Staff Scholarship

While the green production and application of 2D functional nanomaterials, such as graphene flakes, in films for stretchable and wearable technologies is a promising platform for advanced technologies, there are still challenges involved in the processing of the deposited material to improve properties such as electrical conductivity. In applications such as wearable biomedical and flexible energy devices, the widely used flexible and stretchable substrate materials are incompatible with high-temperature processing traditionally employed to improve the electrical properties, which necessitates alternative manufacturing approaches and new steps for enhancing the film functionality. We hypothesize that a mechanical stimulus, in the form of …

Aiche Virtual Communities Of Practice – Supporting Faculty During The Covid-19 Pandemic, Christi L. Patton (Luks)

Chemical and Biochemical Engineering Faculty Research & Creative Works

In response to the COVID-19 pandemic, chemical engineering departments from around the world shifted their course offerings from in-person to online almost instantaneously. The AIChE Education Division immediately responded to this educational shift by developing five Virtual Communities of Practice (VCPs) that allowed faculty to share experiences and best practices as well as provide a network for emotional support. Community creation, methods and materials shared, and surveys related to the impact of this initiative will be discussed.

Spin Coupling In Magnetic Core - Shell Nanoparticles, Corisa Kons

USF Tampa Graduate Theses and Dissertations

Magnetic nanoparticles (NPs) have garnered much interest due to the unique properties that emergewhen compared to their bulk counterparts. In particular, core-shell (CS) NPs offer the ability to tailor the magnetic properties of the system through careful selection of core and shell constituent materials. In this work, the magnetic ordering of CS NPs with contrast in core/shell features (moment, anisotropy, coercivity, etc.) have been investigated using a combination of X-ray magnetic circular dichroism spectroscopy (XMCD) and polarized small angle neutron scattering (SANS). First, temperature-dependent analyses of XMCD and SANS studies were carried out for CS NPs featuring a core composed …

Newmark-Type Pseudo-Three-Dimensional Back-Analysis Of Co-Seismic Landslides In Egkremnoi, Lefkada, Greece, Weibing Gong, Dimitrios Zekkos, Marin Clark, Dalia Kirschbaum

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

A pseudo-three-dimensional (pseudo-3D) methodology to back-analyze coseismic landslides was developed and applied to 68 mapped landslides, which occurred over approximately 1 km2area in Egkremnoi, Greece, during the 2015 Mw6.5 Lefkada earthquake. The methodology is based on a one-dimensional (1D) Newmark-type sliding block model to assess instability and a spatial projection in 3D topography to derive landslide geometry. The strength parameters for modeled landslides that best match the landslide location, area, and volume were derived through an iterative scheme that optimizes the match using predefined matching criteria. The range of different-sized landslides produced shear strength estimates from ~10 to 300 kPa …

Human-Human Hand Interactions Aid Balance During Walking By Haptic Communication, Mengnan Wu, Luke Drnach, Sistania M. Bong, Yun Seong Song, Lena H. Ting

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Principles from human-human physical interaction may be necessary to design more intuitive and seamless robotic devices to aid human movement. Previous studies have shown that light touch can aid balance and that haptic communication can improve performance of physical tasks, but the effects of touch between two humans on walking balance has not been previously characterized. This study examines physical interaction between two persons when one person aids another in performing a beam-walking task. 12 pairs of healthy young adults held a force sensor with one hand while one person walked on a narrow balance beam (2 cm wide x …

Analysis Of The Effectiveness Of Face-Coverings On The Death Ratio Of Covid-19 Using Machine Learning, Ali Lafzi, Miad Boodaghi, Siavash Zamani, Niyousha Mohammadshafie, Veeraraghava Raju Hasti

Purdue University Libraries Open Access Publishing Fund

The recent outbreak of the COVID-19 led to death of millions of people worldwide. To stave off the spread of the virus, the authorities in the US employed different strategies, including the mask mandate order issued by the states’ governors. In the current work, we defined a parameter called average death ratio as the monthly average of the number of daily deaths to the monthly average number of daily cases. We utilized survey data to quantify people’s abidance by the mask mandate order. Additionally, we implicitly addressed the extent to which people abide by the mask mandate order, which may …

Cybert: Cybersecurity Claim Classification By Fine-Tuning The Bert Language Model, Kimia Ameri, Michael Hempel, Hamid Sharif, Juan Lopez Jr., Kalyan Perumalla

Department of Electrical and Computer Engineering: Faculty Publications

We introduce CyBERT, a cybersecurity feature claims classifier based on bidirectional encoder representations from transformers and a key component in our semi-automated cybersecurity vetting for industrial control systems (ICS). To train CyBERT, we created a corpus of labeled sequences from ICS device documentation collected across a wide range of vendors and devices. This corpus provides the foundation for fine-tuning BERT’s language model, including a prediction-guided relabeling process. We propose an approach to obtain optimal hyperparameters, including the learning rate, the number of dense layers, and their configuration, to increase the accuracy of our classifier. Fine-tuning all hyperparameters of the resulting …

Pore-Scale Modeling Of Fluid Flow And Particle Transport In Multi-Scale Porous Media, Bin Wang

LSU Doctoral Dissertations

Nanomaterials have recently gained much interest in the field of petroleum engineering and environmental engineering. Understanding the particle transport mechanisms in geological porous media is important to design fit-for-purpose nanomaterials and certain operating parameters for practical usage of those materials. It has been known that natural rock has multi-scale porosity (macroporosity and microporosity) in nature. The microporosity can have a strong impact on the flow and mass transport, but the microscale physics and macroscopic consequences remain poorly understood.

The first part of this dissertation introduces a new higher-order, locally mass conserving FEM method. Stokes equation and Darcy equation are solved …

A Framework Of Dynamic Data Driven Digital Twin For Complex Engineering Products: The Example Of Aircraft Engine Health Management, Zhenhua Wu, Jianzhi Li

Manufacturing & Industrial Engineering Faculty Publications

Digital twin is a vital enabling technology for smart manufacturing in the era of Industry 4.0. Digital twin effectively replicates its physical asset enabling easy visualization, smart decision-making and cognitive capability in the system. In this paper, a framework of dynamic data driven digital twin for complex engineering products was proposed. To illustrate the proposed framework, an example of health management on aircraft engines was studied. This framework models the digital twin by extracting information from the various sensors and Industry Internet of Things (IIoT) monitoring the remaining useful life (RUL) of an engine in both cyber and physical domains. …

Modeling, Identification, And Stability Analysis Of Inverter-Based Resources Integrated Systems, Miao Zhang

USF Tampa Graduate Theses and Dissertations

More and more stability issues have been observed in real-world inverter-based resources (IBRs) power systems. Stability analysis is highly requested in the industrial area. To have an insight into the root causes of stability issues within IBR integrated systems, e.g, PV, wind, and battery storage systems, the dynamic characteristics should be fully understood.

The approaches are different when considering the presupposition of investigated IBR systems. A reduced-order analytical model of the IBR integrated system can be built if the IBR is treated as a white box. Since the parameters and control structures of converter control can be accessed. This analytical …

Theory And Algorithms For Systems Optimization, Vahid Mahmoodian

USF Tampa Graduate Theses and Dissertations

This dissertation presents four sets of contributions in the field of theory and algorithms for system optimization. In the first set, we introduce a simulation optimization method for redistributing bikes in a free-floating bike sharing system. The second set of contributions is a framework for batching queries in large databases to optimize the data retrieval time. The third set includes two branch-and-bound algorithms to solve minimum multiplicative programming problems and one branch-and-bound algorithm to solve the maximum form of the mentioned problems. At last, the fourth set presents an approach to fairlyassign delivery tasks in an outsourcing last-mile delivery system …

Entrepreneurially Minded Learning In The Unit Operations Laboratory Through Community Engagement In A Blended Teaching Environment, Erick S. Vasquez, Kelly Bohrer, Abraham Noe-Hays, Arthur Davis, Matthew Dewitt, Michael J. Elsass

Chemical and Materials Engineering Faculty Publications

Online and blended learning opportunities in Chemical Engineering curriculum emerged due to COVID-19. After eight weeks of in-person Unit Operations Laboratory sessions, a remote-learning open-ended final project was assigned to student teams. The assignment involved aspects related to entrepreneurial-minded learning (EML) and community-based learning (CBL). Results show correlations between self-directed learning and the EML framework. Continuous support and involvement of a community partner correlate to students' m

Higher Sound Levels In K-12 Classrooms Correlate To Lower Math Achievement Scores, Laura Caroline Brill, Lily M. Wang

Durham School of Architectural Engineering and Construction: Faculty Publications

Sound levels from occupied classrooms have been gathered from 220 classrooms across four grade levels (3, 5, 8 and 11) over six school days each and processed with k-means clustering into speech and non-speech clusters. Three metrics describing the classroom acoustics, including the average daily A-weighted equivalent level for non-speech, the average daily difference between the A-weighted equivalent levels for speech and nonspeech (a signal to noise ratio), and the mid-frequency averaged reverberation time, were analyzed against classroom-aggregated standardized reading and math achievement test scores, while controlling for classroom demographics including socioeconomic status. Interactions between the metrics and demographics were …

Reduction Of Cod And Highly Coloured Mature Landfill Leachate By Tin Tetrachloride With Rubber Seed And Polyacrylamide, Siti Fatihah Ramli, Hamidi Abdul Aziz, Fatehah Mohd Omar, Mohd Suffian Yusoff, Herni Halim, Mohamad Anuar Kamaruddin, Kamar Shah Ariffin, Yung-Tse Hung

Civil and Environmental Engineering Faculty Publications

Tin tetrachloride (SnCl4 ) as a coagulant and rubber seed (Hevea brasiliensis) (RS), and polyacrylamide (PAM) as the coagulant aid were investigated in this work to treat matured and stabilised landfill leachate rich in COD and colour. A standard jar test was conducted at different pH values and dosages of coagulant/coagulant aid. When SnCl4 acted as the primary coagulant, the optimum conditions occurred at pH 8 and 10,000 mg/L dosages, with 97.3% and 81% reductions of colour and COD, respectively. Both RS and PAM were not effective when used alone. When RS was used as the coagulant aid, the dosage …

Investigating Operational Modes In Gallium Nitride Photoconductive Switches, Brad J. Maynard

Electrical and Computer Engineering ETDs

As switching requirements for speed, power, and efficiency become more stringent, advances in wide-bandgap (WBG) materials has enabled their use in high power switching devices. One such device, the photoconductive semiconductor switch (PCSS), while previously constructed from GaAs, shows promise using WBG Mn-doped GaN. Lateral and vertical geometries of PCSS have been produced and evaluated for operation using sub-mJ/ns regime pulsed laser incidence. At fields below 25 kV/cm, the lateral switch operates in the linear regime where modest photocurrent fitting the laser envelope is observed. Above this threshold, the switches demonstrate circuit-limited persistent conductivity (PC) current, in what is presumed …

Microencapsulation Of Thermochromic Materials For Thermal Storage And Energy Efficiency Of Buildings, Abdullatif Hakami

USF Tampa Graduate Theses and Dissertations

Thermochromism and thermochromic materials research and development are of great interest in various applications such as energy efficient building structures, textile industries, thermal or heat storage, antique maintenance processing, and sensors, etc. In general, thermochromic materials have been classified into four categories, including inorganic, organic, polymeric, and hybrid systems, based on their unique material properties and operating conditions. Thermochromic materials have been prepared via different physico-chemical techniques with some of them combined to maximize the yield, stability, and efficiency of the prepared TCMs. Pristine TCMs often undergo severe degradation when exposed to various external stimuli including UV irradiation from sunlight …