Engineering Commons^™

Different Motion Cues Are Used To Estimate Time-To-Arrival For Frontoparallel And Loming Trajectories, Finnegan J. Calabro, Scott A. Beardsley, Lucia M. Vaina

Biomedical Engineering Faculty Research and Publications

Estimation of time-to-arrival for moving objects is critical to obstacle interception and avoidance, as well as to timing actions such as reaching and grasping moving objects. The source of motion information that conveys arrival time varies with the trajectory of the object raising the question of whether multiple context-dependent mechanisms are involved in this computation. To address this question we conducted a series of psychophysical studies to measure observers’ performance on time-to-arrival estimation when object trajectory was specified by angular motion (“gap closure” trajectories in the frontoparallel plane), looming (colliding trajectories, TTC) or both (passage courses, TTP). We measured performance …

Sensitivity Analysis On Mapping Evapotranspiration At High Resolution Using Internal Calibration (Metric), Venkata Naga Ravi Kumar Choragudi

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Mapping EvapoTranspiration at high Resolution using Internal Calibration (METRIC) is most widely used to quantify evapotranspiration (ET) spatially and temporally. It is essential to inspect the model’s response to errors in various parameters used in the model. Landsat 5 images from May 30 2009, July 1 2009 and a Landsat 7 image from September 27 2009 are used in this study. Fourteen different fields composed of Corn, Soybeans, Alfalfa are randomly chosen for each crop type.

Two kinds of errors are addressed in this study. One, with the errors that are transferred and potentially compensated by calibration (Global error) and …

Development Of A Design Procedure For Concrete Traffic Barrier Attachments To Bridge Decks Utilizing Epoxy Concrete Anchors, Benjamin J. Dickey

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

A guide for the design of epoxy anchors for the use in concrete traffic barriers was developed in this study. A series of dynamic bogie tests and static tests was conducted on single and double anchors. The dynamic increase factor for the noted anchors was determined to be 1.06. Protective epoxy coatings for the anchors was observed to contribute to a 9 percent decrease in anchorage strength. The effects of anchors located in close proximity to each other was also investigated. Calibration factors were developed to apply recommended changes to the ACI code for use in bridge rail anchorages.

A …

Expanding The Length Of Jointless Bridges By Providing Rotational Capacity Over The Pile Head, Ardalan Sherafati

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Jointless bridges have been in service for more than 50 years. Since no expansion joint is utilized in these structures, they have longer service life, reduced maintenance and construction costs, improved riding quality, and added redundancy. Because of integrity of the superstructure with the substructure, the thermal movements as well as other longitudinal movements are transferred to substructure. These lateral movements can induce relatively large forces and moments in the substructure elements including the abutment and the piles. Typically, flexible foundations which include single row of piles are preferred in jointless bridges to reduce the stiffness of the system against …

A Novel Telecommunications-Based Approach To Mathematical Modeling Of Hiv Infection, Aaron T. Sharp

Department of Computer Electronics and Engineering: Dissertations, Theses, and Student Research

It is well known that biological systems utilize communication in some form, one prolific example of this is the propagation of HIV (Human Immunodeficiency Virus) in the human body. By modeling HIV infection as a communication system, we hope to gain a unique insight into HIV and biological communication systems in general. Such a model would provide researchers a platform for experimenting and simulating various biological communication systems. We have previously developed a layered communication protocol for interpreting biological communication systems using telecommunications paradigms and will apply said model to HIV proliferation. We will also demonstrate the effectiveness of the …

Hydrologic Evaluation Of Established Rain Gardens In Lincoln, Nebraska Using A Storm Runoff Simulator, Andrew R. Anderson

Department of Environmental Engineering: Theses and Other Student Research

Increased urbanization has resulted in water quality and flooding problems for many receiving waters in the United States. Bioretention, or rain gardens, is one of the most widely popular and effective best management practices in low impact development (LID), which strives to return a watershed to a predevelopment hydrologic regime. Many studies have evaluated large bioretention cells in research settings. There is little information on the effectiveness of homeowner-maintained rain gardens that rely on deep percolation as the method for water exfiltration. Additionally, few studies address rain garden performance in cold, arid, or semi-arid climates found in the Midwest U.S. …

Economic Analysis Of Continuous Monitoring Of Commercial Truck Tire Pressure Using Tire Pressure Monitoring Systems (Tpms) And Rfid Technologies, Afolabi A. Ogunwemimo

Department of Industrial and Management Systems Engineering: Dissertations, Theses, and Student Research

The trucking industry is a major contributor to the US economy. By providing the essential services of transportation and distribution needed in today’s dynamic industry, the transportation industry has evolved into an integral player in various supply chains. The trucking industry is the largest transportation provider for other industries and employs 10.1 million workers in the United States (ATA, 2003).

This research is an analysis of the economic impact of maintaining proper air pressure in the tires of commercial trucks. Various studies have been carried out on understanding the relationship between tire pressure and fuel consumption (National Research Council, 2006). …

Feasibility Analysis And Concept Development Of A Crash Cushion Diaphragm Structure For High-Speed Race Tracks, Curt Lee Meyer

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

A new diaphragm and dual guide rail system was designed for use in a crash cushion for high-speed race tracks. These structural components were designed to provide sufficient lateral support to redirect impacting vehicles and compress the energy-absorbing elements of the crash cushion. The primary design criteria stated that the diaphragm/guide rail system should be capable of withstanding a 100-kip lateral impact load. The guide rail was to be configured in order to not require replacement after a design impact event. Initial design and modeling resulted in two candidates for guide rail sections which were evaluated during physical testing. The …

Design Of A Low Noise Amplifier For Wireless Sensor Networks, Ting Liu

Graduate Theses and Dissertations

CMOS technology becomes important in Radio Frequency (RF) communication systems which include both a receiver and a transmitter. In a high performance radio receiver, the Low Noise Amplifier (LNA) is the first circuit, and its noise performance dominates the entire receiver. Depending upon the system in which they are used, LNAs can be designed according to various topologies and structures. The LNA needs to have matched input impedance, and at the same time it should amplify the small amplitude input signal without adding too much noise and still have the minimal power consumption. It also needs a good interface with …

Degradation Of Polystyrene Foam Under Radiant Heat Flux, James Butler

Graduate Theses and Dissertations

As the demand for liquefied natural gas has increased, safety concerns about the performance of transport vessels under fire conditions have been raised. Current codes for the sizing of the pressure relief systems require that the vessels are able to withstand an emmissive heat flux of 108kW/m2 and do not take into account the effects of insulation loss due to thermal decomposition of the insulation materials. To address this possible oversight in the current code models were presented to a working group organized by the Society of International Gas Tanker and Terminal Operators Ltd. focusing on the decomposition rate of …

Water Quality Trends For Section 319 Priority Watersheds In Northwest Arkansas, 1997-2010, Bryan William Bailey

Graduate Theses and Dissertations

Northwest Arkansas contains two Section 319 Priority Watersheds that the Arkansas Natural Resources Commission (ANRC) has identified as being impacted by point and nonpoint sources of pollution (i.e., phosphorus, nitrogen, and sediment), and the Arkansas Water Resources Center (AWRC) has monitored the water quality at several sites within these watersheds. Water-quality data has been collected over the last decade within the Illinois River Watershed (HUC #11110103) and the Upper White River Basin (Beaver Reservoir HUC# 11010001), each watershed containing three sampling sites. The Illinois River Watershed sites are located on the Illinois River, Osage Creek, and Ballard Creek, and the …

Photodetectors And Photovoltaic Devices Based On Semiconductor Nanomaterials, Jiang Wu

Graduate Theses and Dissertations

Photodetectors based various nanostructures and plasmon enhanced solar cells are investigated in this dissertation. The motivation of the dissertation rise is driven by urgent need of both high efficiency photodetectors and solar cells.

First, quantum dot infrared photodetectors have been intensely investigated due to their promise in high performance photodetectors. However, the strain-driven growth of quantum dots has hindered the progress of quantum dot photodetectors. The presence of strain in the device presents complexity in designing as well as defects. Therefore, in this project, new designs of quantum dot photodetector structures are presented to improve the control over detection wavelength. …

Investigation Of A Floating Load Buck Dc-Dc Switching Converter, Hong Tan

Graduate Theses and Dissertations

A floating load buck DC-DC switching converter was analyzed, simulated, designed and prototyped. The floating load buck converter is first compared to the conventional buck converter. It was found that both the floating load buck converter and conventional buck converter exhibit similar conversion characteristics despite the differences in the placement of their output inductors. A floating load buck converter was designed to be used as a high-voltage off-line light-emitting diodes (LEDs) driver using a Texas Instruments' TPS92001 controller. Finally, the characteristics of this floating load buck converter LED driver were experimentally examined.

Development Of Spray Cooling For High Heat Flux Electronics, Jeremy Scott Junghans

Graduate Theses and Dissertations

The thermal demands of modern day electronic systems require innovative thermal solutions. Spray cooling has proven to be able to cool heat fluxes orders of magnitude higher than traditional cooling methodologies. This work includes a comparison of spray cooling to standard thermal management methodologies. Key system parameters and considerations are discussed. The properties of available packaging materials and their effect on the reliability of a spray cooled system are presented. Parameters such as fluid temperature, droplet size, fluid velocity and flow rate all directly impact performance and are detailed in this work. Finally, results from of a wide range of …

Design And Implementation Of Metamaterial Based Strain Sensor Using Aperture Coupled Antenna, Michael Brandon Buscher

Graduate Theses and Dissertations

Strain sensors are used to convert the physical measured quantity of strain into an electrical signal suitable for processing by electronic equipment. Traditional strain sensors are comprised of a thin flexible film with a resistive pattern traced on the surface. As the sensor is deformed, the electrical resistance changes proportionally, giving a direct measure of the strain incurred. Metamaterials, particularly split ring resonators (SRR), lend themselves as a valuable tool for sensing applications due to their highly resonant nature and their very narrow bandwidth (high Q-factor). Due to very high field localization effects, they are extremely sensitive to both the …

Modeling And Characterization Of P-Type Silicon Carbide Gate Turn Off Thyristors, Osama Shihadeh Saadeh

Graduate Theses and Dissertations

Silicon carbide (SiC) power semiconductor devices have emerged in the past decade as the most promising technology for next generation power electronic applications ranging for electric vehicles to grid-connected power routing and conversion interfaces. Several devices have been developed, and even some have been released commercially, including diodes, MOSFETs, JFETs, thyristors, gate turn-off thyristors, and IGBTs. The model development, characterization and experimental validation of SiC p-type Gate Turn-off Thyristors (GTO) is presented in this work. The GTO device in this work is being used as part of a SiC-based solid-state fault current limiter under development at the University of Arkansas' …

Distributed Electrical Power System In Cubesat Applications, Robert Burt

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The cubesat spacecraft was conceived over ten years ago. Since that time, close to 100 cubesat satellites have either been launched or are in the process of construction. Although started as an educational teaching tool, the cubesat is gaining popularity in the satellite industry and is making inroads as a standard architecture for many nano and pico satellite applications. The electrical power system for the cubesat class satellites almost exclusively conforms to a centralized architecture.

This thesis researches the potential of using a distributed architecture for the cubesat power system. There are several key advantages of a distributed architecture that …

Environmental Sensor Anomaly Detection Using Learning Machines, Erick F. Conde

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The search for improvements in the quality assurance/quality control (QA/QC) of real-time environmental measurements has been a field well exploited in recent years. These measurements describe actual environmental conditions and processes that provide relevant information upon which water quality management decisions are based. In situ sensors (located at the site of interest) are commonly used for such real-time measurement purposes. However, the performance of these types of sensors can be affected by such things as human factors, lack of necessary maintenance, flaws on the transmission line or any part of the sensor, and unexpected changes in the sensors surrounding conditions. …

Optimization Of Dissolved Air Flotation For Algal Harvesting At The Logan, Utah Wastewater Treatment Plant, Andrew R. Elder

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Research being completed at the Logan, UT wastewater treatment plant could provide a locally-sourced gasoline replacement by collecting algae that grows naturally. This process would also provide the City of Logan with a method to meet certain standards set by the state of Utah.

Problem and proposed solution:

The water leaving Logan’s wastewater treatment plant has high levels of phosphorus and nitrogen, two elements that are found in all wastewater treatment plants. These two substances need to be controlled, because they kill fish and cause pond scum to grow in recreational reservoirs downstream. A unique method has been found to …

Asymptotic Multiphysics Modeling Of Composite Beams, Qi Wang

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A series of composite beam models are constructed for efficient high-fidelity beam analysis based on the variational-asymptotic method (VAM). Without invoking any a priori kinematic assumptions, the original three-dimensional, geometrically nonlinear beam problem is rigorously split into a two-dimensional cross-sectional analysis and a one-dimensional global beam analysis, taking advantage of the geometric small parameter that is an inherent property of the structure.

The thermal problem of composite beams is studied first. According to the quasisteady theory of thermoelasticity, two beam models are proposed: one for heat conduction analysis and the other for thermoelastic analysis. For heat conduction analysis, two different …

Axisymmetric Finite Element Modeling Of Adhesive Joint Between A Laminated Composite And Metal Cylinder, Casey A. Talbot

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Because lowering weight as much as possible is desirable in all applications designed to go to space, the use of composite materials is desirable. Composites are materials that are made up of two or more separate materials usually with significantly different characteristics which remain separate and distinct in their completed state. Fiber-reinforced epoxy composites, in general, are very strong and light. Because most space structures cannot solely be made of composites, a method to join them with metals is needed. Adhesive joining, or gluing, has been determined to be the most promising option.

For the joining technique to be used, …

Inkjet-Printed Highly Transparent Solar Cell Antennas, Jesus A. Arellano

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Small satellites, especially Cube Satellites (CubeSats), have become important vehicles for space exploration. One of the challenges CubeSats face is limited surface area. This limitation poses a question for antenna design–where to mount the antenna? Transparent antenna is a solution to resolve the competition between solar cells and antennas for surface area. The transparent antennas can be directly integrated on top of solar cells without requiring additional space. It is for this reason that this thesis focuses on the integration of highly transparent meshed antenna with solar cells. Even though transparent antennas allow light to travel light through them, they …

Effect Of Vegetation On The Accumulation And Melting Of Snow At The Tw Daniels Experimental Forest, Vinod Mahat

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Snow melt is an important component of Western US water resources, accounting for about 50-80% of the annual runoff. Water resources management requires prediction of runoff from snowmelt accounting for the variability of vegetation present in heterogeneous watersheds. This dissertation has examined ways to improve snowmelt modeling capability to better account for vegetation canopy effects on snowmelt and has presented enhancements to an energy balance model that include i) an improved representation of the transmission of radiation through the canopy, ii) an improved representation of the atmospheric transport of heat and water vapor between the snow on the ground, in …

Measuring The Differences In Spatial Ability Between A Face-To-Face And A Synchronous Distance Education Undergraduate Engineering Graphics Course, Scott D. Greenhalgh

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A study was conducted in the Engineering and Technology Education Department at Utah State University by Scott Greenhalgh and Gary Stewardson to measure and compare a face-to-face engineering graphics course with a synchronous distance education engineering graphics course by identifying the impact of the teacher's physical presence on students' spatial ability. This study is unique because it involves laboratory classes in a science, technology, engineering, and math (STEM) field with greater emphasis on hands-on laboratory experiences and skills rather than mastery of information and knowledge. The potential for impact of the study extends beyond a few courses in a specific …

Evaluation Of An Incompressible Energy-Vorticity Turbulence Model For Fully Rough Pipe Flow, Doug F. Hunsaker

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Traditional methods of closing the Boussinesq-based Reynolds-averaged Navier-Stokes equations are considered, and suggestions for improving two-equation turbulence models are made. The traditional smooth-wall boundary conditions are shown to be incorrect, and the correct boundary conditions are provided along with sample solutions to traditional models. The correct boundary condition at a smooth wall for dissipation-based turbulence models is that which forces both the turbulent kinetic energy and its first derivative to zero. Foundations for an energy-vorticity model suggested by Phillips are presented along with the near-smooth-wall behavior of the model. These results show that at a perfectly smooth wall, the turbulent …

Optimization Of A Low Reynold's Number 2-D Inflatable Airfoil Section, Todd A. Johansen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A stand-alone genetic algorithm (GA) and an surrogate-based optimization (SBO) combined with a GA were compared for accuracy and performance. Comparisons took place using the Ackley Function and Rastrigin's Function, two functions with multiple local maxima and minima that could cause problems for more traditional optimization methods, such as a gradient-based method. The GA and SBO with GA were applied to the functions through a fortran interface and it was found that the SBO could use the same number of function evaluations as the GA and achieve at least 5 orders of magnitude greater accuracy through the use of surrogate …

Tracking Web Video Topics: Discovery, Visualization, And Monitoring, Juan Cao, Chong-Wah Ngo, Yong-Dong Zhang, Jin-Tao Li

Research Collection School Of Computing and Information Systems

Despite the massive growth of web-shared videos in Internet, efficient organization and monitoring of videos remains a practical challenge. While nowadays broadcasting channels are keen to monitor online events, identifying topics of interest from huge volume of user uploaded videos and giving recommendation to emerging topics are by no means easy. Specifically, such process involves discovering of new topic, visualization of the topic content, and incremental monitoring of topic evolution. This paper studies the problem from three aspects. First, given a large set of videos collected over months, an efficient algorithm based on salient trajectory extraction on a topic evolution …

Galaxy Browser: Exploratory Search Of Web Videos, Lei Pang, Song Tan, Hung-Khoon Tan, Chong-Wah Ngo

Research Collection School Of Computing and Information Systems

Most search engines return a ranked list of items in response to a query. The list however tells very little about the relationship among items. For videos especially, users often read to spend significant amount of time to navigate the search result. Exploratory search presents a new paradigm for browsing where the browser takes up the role of information exploring and presents a well-organized browsing structure for users to navigate. The proposed interface Galaxy Browser adopts the recent advances in near-duplicate detection and then synchronizes the detected near-duplicate information with comprehensive background knowledge derived from online external resources. The result …

Cross Media Hyperlinking For Search Topic Browsing, Song Tan, Chong-Wah Ngo, Hung-Khoon Tan, Lei Pang

Research Collection School Of Computing and Information Systems

With the rapid growth of social media, there are plenty of information sources freely available online for use. Nevertheless, how to synchronize and leverage these diverse forms of information for multimedia applications remains a problem yet to be seriously studied. This paper investigates the synchronization of multiple media content in the physical form of hyperlinking them. The ultimate goal is to develop browsing systems that author search results with rich media information mined from various knowledge sources. The authoring enables the vivid visualization and exploration of different information landscapes inherent in search results. Several key techniques are studied in this …

On The Pooling Of Positive Examples With Ontology For Visual Concept Learning, Shiai Zhu, Chong-Wah Ngo, Yu-Gang Jiang

Research Collection School Of Computing and Information Systems

A common obstacle in effective learning of visual concept classifiers is the scarcity of positive training examples due to expensive labeling cost. This paper explores the sampling of weakly tagged web images for concept learning without human assistance. In particular, ontology knowledge is incorporated for semantic pooling of positive examples from ontologically neighboring concepts. This effectively widens the coverage of the positive samples with visually more diversified content, which is important for learning a good concept classifier. We experiment with two learning strategies: aggregate and incremental. The former strategy re-trains a new classifier by combining existing and newly collected examples, …