Engineering Commons^™

Predicting General Aviation Accidents Using Machine Learning Algorithms, Bradley S. Baugh

Doctoral Dissertations and Master's Theses

No abstract provided.

On-Chip Nonreciprocal Components For Full-Duplex Communications And Gaussian Regulated Gate Driver For Electromagnetic Interference Reduction, Chang Yang

Electrical Engineering Theses and Dissertations

This dissertation is comprised of two unrelated design endeavors. The first one is about two CMOS nonreciprocal components: 1) an isolator and 2) a circulator. To make the components compact enough for the next generation communication systems with wide bandwidth, both components operate at 100 GHz band for full-duplex transceivers for ultra-high-data-rate millimeter-wave wireless communication. The proposed nonreciprocal structures are based on a time-domain modulation by signals at around 1/6 of the RF frequencies and spatial duplexing over the RF signal paths, demonstrating over 45 dB isolation in a bandwidth of 1.5 GHz over the tuning range of 85-110 GHz. …

A Comparative Study Of Cannabinoids & Cb1 Receptor Gi Signaling, Haley Kristen Andersen

Theses and Dissertations

The legalization of medical marijuana has highlighted cannabinoids as a potential, opioid-free therapeutic option for pain management; however, the rise in illicit synthetic cannabinoid-induced toxicity has demonstrated the need to outline cannabinoid molecular signaling. The cannabinoid-type 1 (CB1) receptor is an endogenous G protein-gated receptor (GPCR), well-expressed in the central nervous system (CNS) associated with modulating neuronal activity. Cannabinoid agonists bind to the CB1 receptor resulting in the inhibitory G protein (Gi) complex to dissociate into two subunits, Gβγi and Gαi. The Gαi subunit inhibits adenylyl cyclase, leading to a decrease in cyclic adenosine monophosphate (cAMP). The Gβγi subunit activates …

Agent-Based Modelling Of Values: The Case Of Value Sensitive Design For Refugee Logistics, Christine Boshuijzen-Van Burken, Ross J. Gore, Frank Dignum, Lamber Royakkers, Phillip Wozny, F. Leron Shults

VMASC Publications

We have used value sensitive design as a method to develop an agent-based model of values in humanitarian logistics for refugees. Schwartz’s theory of universal values is implemented in the model in such a way that agents can make value trade-offs, which are operationalized into a measure of refugee wellbeing and a measure of public opinion about how the refugee logistics is being handled. By trying out different ‘value scenarios’, stakeholders who are responsible for, or involved in refugee logistics can have insights into the effects of various value choices. The model is visualized and made usable as a platform …

Mode Analysis And Applications Of Three-Layer Step-Index And Depressed-Core Optical Fibers, Xiaokang Lian

Doctoral

Optical fibersplay important roles in telecommunication, imaging, sensing, lasers and amplifiers. The rapid development of fiberopticsover the past decades has beenunderpinnedbyvarious designs of the optical fibers and bythe rapid improvement of the understanding of the waveguiding mechanismsand associated models. According to the cross-section refractive index distribution, optical fibers can be generally classified into four basic types: two-layer step-index fiber, three-layer step-index fiber, three-layer depressed-core fiber and hollow-core fiber.Among these four basic fibertypes,the modeproperties and the applications of the three-layer step-index and depressed-core fibers have notbeensufficiently investigated. This thesis presents a detailedmode analysis in three-layer step-index and depressed-core fibers and their …

An Equity Focused Study On The Trip Temporal Distributions Of Vulnerable Road Users, Santiago Espinosa Wild

Civil and Environmental Engineering Master's Project Reports

The United States is a megadiverse nation with a transportation system that, for decades, was designed to serve primarily able-bodied, white, male motorists. This legacy creates a situation in which varying socio-demographic groups experience the transportation system differently with contrasting safety, accessibility, and convenience outcomes. This project introduces descriptive statistics and binary logistic models that provide transportation professionals and policy makers with a quantitative understanding on how, why, and when certain socio-demographic groups are more likely to engage in a trip. This project provides tools to measure and understand the equity implications of a wide array of transportation policy decisions. …

Rapid Repair Of Seismically Vulnerable Bridge Columns Following Earthquake Induced Damage, Gregory H. Norton

Civil and Environmental Engineering Master's Project Reports

The Cascadia Subduction Zone (CSZ) earthquake has a high probability of occurrence within our lifetime, threatening bridges across the Pacific Northwest. Damage is expected to be geographically spread throughout the region and will have a nearly simultaneous impact on transportation through several important corridors. While bridge repair and replacement will ultimately be needed, priority will be placed on resuming mobility such that repairs will need to be implemented quickly. In an effort to anticipate this need, a repair method is being developed for rapid repair with the goal of achieving semi-permanent installation that also considers the different bridge damage states …

Modeling Airflows And Voc Source Strengths For An Occupied School, Brett Stinson

University Honors Theses

Volatile organic compounds (VOCs) are a group of air pollutants that can adversely impact human health, engage in chemistry indoors, and meaningfully degrade indoor and outdoor urban air quality. While extensive research with regard to VOC emission rates from indoor sources has been conducted, it was not until recently that this work began to focus on characterizing emissions from humans and human activity in depth. As buildings are constructed to be increasingly airtight, and the materials utilized are chosen to reduce VOC emissions, it follows that human contributions are poised to become increasingly important indoor sources of VOCs. Utilizing data …

The Seasonal Effects Of Photovoltaic Cells On Sedum Eco Roof Substrate Moisture, Brook M. Thompson

University Honors Theses

This paper investigates a combined PV eco roof system and analyzes the soil moisture levels in front of the panels and directly underneath the PV Cells on an experimental ecoroof platform in Portland, Oregon. The purpose of the study was to examine how PV Cells create differences in the moisture level of the soil on the ecoroof. Four moisture sensors were set in different quadrants in four experimental testbeds, and the moisture level data was recorded from October 18^th, 2018 to September 10^th, 2019. The study found that in with heavy rainfall, the front of the …

Organ Segmentation Of Pediatric Computed Tomography (Ct) With Generative Adversarial Networks, Chi Nok Enoch Kan

Master's Theses (2009 -)

Accurately segmenting organs in abdominal computed tomography (CT) is crucial for many clinical applications such as organ-specific dose estimation. With the recent emergence of deep learning techniques for computer vision, many powerful frameworks are proposed for organ segmentation in abdominal CT images. A major problem with these state-of-the-art methods is that they depend on large amounts of training data to achieve high segmentation accuracy. Pediatric abdominal CTs are particularly hard to obtain since these children are much more sensitive to ionizing radiation than adults. It is extremely challenging to train automatic segmentation algorithms on pediatric CT volumes. To address these …

Impact Of Sewershed Characteristics On Rainfall Derived Inflow And Infiltration, Spencer Michael Sebo

Master's Theses (2009 -)

Cities rely on sewer systems to transport wastewater and stormwater, but sometimes these systems are overwhelmed, and their capacity is exceeded due to excess water in the system from rainfall derived inflow and infiltration. This can lead to overflows and backups that can be detrimental to health and property. Excess water from rainfall derived inflow and infiltration enters a sewer system through a multitude of ways, including downspout connections, foundation drains, pipe joints, and broken pipes. Identifying these sources individually can be time intensive and expensive if entire service areas need to be addressed. High level screening tools are therefore …

A Novel Framework Using Neutrosophy For Integrated Speech And Text Sentiment Analysis, Florentin Smarandache, Kritika Mishra, Ilanthenral Kandasamy, Vasantha Kandasamy W.B.

Branch Mathematics and Statistics Faculty and Staff Publications

With increasing data on the Internet, it is becoming difficult to analyze every bit and make sure it can be used efficiently for all the businesses. One useful technique using Natural Language Processing (NLP) is sentiment analysis. Various algorithms can be used to classify textual data based on various scales ranging from just positive-negative, positive-neutral-negative to a wide spectrum of emotions. While a lot of work has been done on text, only a lesser amount of research has been done on audio datasets. An audio file contains more features that can be extracted from its amplitude and frequency than a …

Enginews, Fall 2020, School Of Computer Science & Engineering

News, Magazines and Reports

In this issue:

COVID Adjustments • Summer Internship + COVID study with Gabriel Bitencourt • IDEA Lab News with Chelsea Coelho • Recent Publications and Press Releases • Student Quotes.

Overcoming Anaerobic Digestion Toxicity Of Aqueous Liquid From Wastewater ‎Solids Pyrolysis, Seyedehfatemeh Seyedi

Dissertations (1934 -)

Pyrolysis treats and potentially recovers energy from wastewater solids (WWS). ‎Aqueous pyrolysis liquid (APL), however, is produced and its management is a ‎bottleneck to pyrolysis full-scale application. To overcome this bottleneck, ‎anaerobic digestion (AD) may be a possible method to manage APL, but APL ‎digestion has not been conclusively demonstrated. In AD, a select group of ‎microorganisms convert organic chemicals to biogas containing methane that ‎can be used as a fuel. In this dissertation work, APL derived from WWS pyrolysis ‎was successfully converted into methane as the sole substrate and as a co-‎digestate with synthetic primary sludge in long-term, continuous …

Design Of Novel Experiments And Analyses For Head And Spine Trauma Biomechanics, John Robert Humm

Dissertations (1934 -)

Previous biomechanics research studies have used both whole-body and isolated postmortem human surrogate experiments to define human injury tolerances, advance safety in injury producing environments, and promulgate standards for design of injury mitigating systems. Recent developments in transportation and sports-related fields have led to an increasing need to determine tolerances for combined loading (multi-axis) scenarios. This dissertation demonstrates the efficacy of the novel experimental design and analysis to head and spine trauma in these modalities. The first topic was the design of a novel experiment to examine the effect oblique loading on the tension tolerance of the lumbar spine. To …

Stochastic Methods For Fine-Grained Image Segmentation And Uncertainty Estimation In Computer Vision, Philipe Ambrozio Dias

Dissertations (1934 -)

In this dissertation, we exploit concepts of probability theory, stochastic methods and machine learning to address three existing limitations of deep learning-based models for image understanding. First, although convolutional neural networks (CNN) have substantially improved the state of the art in image understanding, conventional CNNs provide segmentation masks that poorly adhere to object boundaries, a critical limitation for many potential applications. Second, training deep learning models requires large amounts of carefully selected and annotated data, but large-scale annotation of image segmentation datasets is often prohibitively expensive. And third, conventional deep learning models also lack the capability of uncertainty estimation, which …

Analysis Of Bristle-Tip Impact Crater For Wire Impact Tool, Jian Zhang

Dissertations (1934 -)

Bristle blasting is a novel method that is rapidly gaining widespread acceptance among engineers and practitioners in the surface preparation industry. This process contains the use of a specially designed wire bristle tool that is precisely tuned to the spindle speed of a power tool that rotates at approximately 2,500 rpm. That is, the principle of operation is based upon synchronized/repeated impact and rebound of bristle tips with the target surface, leading to a multitude of impact craters that remove corrosion, expose fresh substrate material, and generate anchor profile. Hence, it is important to develop a model to research the …

Study Of Techniques To Enhance The Performance Of Concrete Members Strengthened By Externally Bonded Composite Materials, Zhao Wang

Dissertations (1934 -)

External bonding of fiber reinforced polymer (FRP) composite materials has been widely recognized as a popular technique for strengthening concrete structures. To find advanced strategies to improve the bond behavior of externally bonded composites strengthened concrete, three major tasks were conducted in this study: experimental work, finite element (FE) analysis, and reliability analysis. The mechanical properties and the deterioration due to water absorption of carbon nanofibers (CNFs) epoxy composites with different contents of CNFs were tested through uniaxial tensile test. According to the tensile test results, adding CNFs could significantly enhance the tensile behavior for epoxy resin. Because adding proper …

Deep Learning For Quantitative Susceptibility Mapping Reconstruction, Juan Liu

Dissertations (1934 -)

Quantitative susceptibility mapping (QSM) is a magnetic resonance imaging (MRI) technique that estimates tissue magnetic susceptibility from Larmor frequency offset measurements. The generation of QSM requires solving ill-posed background field removal (BFR) and field-to-source inversion problems. Incorrect BFR often introduces erroneous local field outputs and subsequently affects susceptibility quantification accuracy. Inaccurate field-to-source inversion often causes large susceptibility estimation errors that appear as streaking artifacts in the QSM, especially in massive hemorrhagic regions. Because current QSM techniques struggle to generate reliable QSM, the clinical translation of QSM is greatly hindered. Recently, deep learning (DL) has achieved state-of-the-art performance in many computer …

Hydrologic Impacts And Trade-Offs Associated With Developing Oil Palm For Bioenergy In Tabasco, Mexico, Azad Heidari, Alex Mayer, David Watkins, María Mercedes Castillo

Michigan Tech Publications, Part 1

Study region: Oil palm cultivation has rapidly expanded worldwide due to demands for food oils and the potential for liquid fuel production. However, there is a scarcity of research on the hydrologic impacts of oil palm plantations at a watershed scale, especially in Latin America. We focus on a watershed typical of intensive palm oil production in Tabasco, Mexico. Study focus: A Soil and Water Assessment Tool model was calibrated to simulate long-term streamflow in the study watershed. The plant growth module was calibrated for leaf area index (LAI) and fruit yield simulations. Oil palm development scenarios were simulated to …

Geometric Analysis Of The Doppler Frequency For General Non-Stationary 3d Mobile-To-Mobile Channels Based On Prolate Spheroidal Coordinates, Michael Walter, Dmitriy Shutin, Martin Schmidhammer, David W. Matolak, Alenka Zajic

Faculty Publications

—Mobile-to-mobile channels often exhibit time-variant Doppler frequency shifts due to the movement of transmitter and receiver. An accurate description of the Doppler frequency turns out to be very difficult in Cartesian coordinates and any subsequent algebraic analysis of the Doppler frequency is intractable. In contrast to other approaches, we base our investigation on a geometric description of the Doppler frequency with the following three mathematical pillars: prolate spheroidal coordinate system, algebraic curve theory, and differential forms. The prolate spheroidal coordinate system is more appropriate to algebraically investigate the problem. After the transformation into the new coordinate system, the theory of …

Ultrasonic Nondestructive Evaluation Using Non-Contact Air-Coupled Lamb Waves, Wenfeng Xiao

Theses and Dissertations

Ultrasonic Lamb waves have been proved as an effective nondestructive evaluation (NDE) method due to their ability to propagate a long distance with less energy loss as well as their sensitivity to various defects on the surface or inside the structure. However, there are still challenges towards using them as a rapid inspection method for complex structural geometries, various damage types, and harsh environments, such as efficiency in Lamb wave actuation and sensing, understanding of the complicated multi-modal Lamb wave propagation, and robust detection algorithms for damage quantification and evaluation. To address these challenges, this dissertation focuses on developing a …

Volume Frequency Response Method For Determining Mass Transfer Mechanisms Of O2 In Carbon Molecular Sieve 3k172, Olivia Smithson

Theses and Dissertations

Carbon molecular sieves (CMS) have grown more desirable over the years as an adsorbent for industrial separation processes as CMS technology has advanced. CMS is commonly used in nitrogen inerting (i.e, oxygen removal from air), carbon dioxide removal from methane and oxygen purification. However, knowledge of the dynamic behavior of these gases on CMS is needed to design and operate efficient and effective separation processes. For this reason, the mass transfer resistances within the micropore at both low and high frequencies were characterized using frequency response, COMSOL Multiphysics modeling, and MATLAB optimization , because frequency response methods have demonstrated the …

Engaging Farmers And The Agriculture Industry Through The Testing Agricultural Performance Solutions Program, Charles A. Burr, Daran Rudnick, Matt Stockton, Robert Tigner, Krystle Rhoades

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The University of Nebraska–Lincoln Testing Agricultural Performance Solutions (TAPS) program involves use of farm management competitions to increase engagement across producers, industry, and universities.Participants make several management decisions throughout the growing season in a controlled field trial held at the university research station. Results are analyzed, and awards are presented for most profitable farm, most efficient farm, and farm with the greatest grain yield. The TAPS program involves several techniques for facilitating participatory assistance, including two-way communication and transformational learning. It has resulted in participants' questioning their past management decisions and realizing that they need to improve their marketing skills …

Introduction To Special Issue Of Irrigation Science: Improving Irrigation Management Across The Ogallala Aquifer, Usa, Allan A. Andales, Daran Rudnick, José L. Chávez

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Groundwater stored in aquifers is a major source of irrigation water for many agricultural regions that receive insufficient precipitation for crop production. In the U.S.A., the High Plains aquifer (HPA) that underlies parts of Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming supplies irrigation water for agricultural production. The HPA underlies around 450,658 km² (174,000 mi²) of which the Ogallala aquifer is the principal geologic formation underlying 347,059 km² (134,000 mi²) (Gutentag et al. 1984). The Ogallala aquifer is primarily a water table (unconfined) aquifer with saturated thickness ranging from 0 …

A Centralised Multi-Objective Model Predictive Control For Biventricular Assist Devices, Vivian Koh Ci Ai

Student Works (2020-2029)

Heart failure is defined as failure of heart to deliver adequate blood flow rate to support tissue perfusion. Heart failure can be treated by implantation of a left ventricular assist device (LVAD) for left heart failure patients, or a biventricular assist device (BiVAD) for bi-heart failure patients. Since left heart failure predominates right heart failure, all commercial ventricular assist devices are LVADs. Therefore, two LVADs are frequently used as BiVAD for bi-heart failure patients. Clinically, the constant speed (CS) control of BiVAD fails to adapt pump flow rate according to physiological changes, thus putting patients at risk of ventricular suction …

Anomalous Growth Of Al8Mo3 Phase During Interdiffusion And Reaction Between Al And Mo, Abhishek Mehta, Le Zhou, Dennis D. Keiser Jr., Yongho Sohn

Mechanical Engineering Faculty Research and Publications

No abstract provided.

Development Of A Grass Measurement Optimisation Tool To Efficiently Measure Herbage Mass On Grazed Pastures, D. J. Murphy, B. O'Brien, Michael D. Murphy

Publications

Accurate and efficient estimation of herbage mass is essential for optimising grass utilisation and increasing profit for pasture farming. There is no definitive sampling protocol for grass measurement on Irish pastures. This paper presents the Grass Measurement Optimisation Tool (GMOT), designed to generate measurement protocols that optimise for time and accuracy. The GMOT was designed in the form of a decision support tool that generates interactive paddock maps that guide the farmer on how to optimally measure their pastures in a random stratified manner based on GPS co-ordinates, resulting in accurate non-biased estimations of mean herbage mass. Rising plate meter …

Detection And Estimation Of Inundation And Associated Risks Using Traffic And Monitoring Cameras And Image Processing Under Extreme Flooding Conditions, Suyun Ham Ph.D, Seongjin Noh Ph.D, Dong-Jun Seo Ph.D, Yin Chao Yu, Sangoo Kang

Publications

The main objective of this project is to develop an inundation detection and evaluation framework using images from traffic monitoring cameras and reliable flood monitoring under extreme precipitation conditions. This study presents a comparative assessment of image enhancement and segmentation techniques to automatically identify the flash flooding from the low-resolution images taken by traffic-monitoring cameras. Due to inaccurate equipment in severe weather conditions (e.g., raindrops or light refraction on camera lenses), low-resolution images are subject to noises that degrade the quality of information. De-noising procedures are carried out for the enhancement of images by removing different types of noises. After …

Real-Time Early Detection And Monitoring Of Flooding Using Low-Cost Highly Sensitive Ultrasound Sensing Of Water Level, Suyun Ham Ph.D, Seongjin Noh Ph.D, Dong-Jun Seo Ph.D, Sanggoo Kang, Dafnik Saril Kumar David

Publications

Flooding poses safety hazards to motorists, emergency and maintenance crews and may cause costly damage to transportation infrastructure and its operation. Flash flooding, in particular, causes the most flood-related deaths According to NOAA, in 2017 alone, flash flooding also caused $60.7 billion worth of economic damage. Low-water crossings are among the first places where deaths and significant damages to vehicles occur during flooding. With flash flooding, when a critical corridor is blocked by a high level of water, it affects the safety of the general public. To keep the critical corridors open as long as possible, and to minimize losses …