Engineering Commons^™

Wall And Ground Movements In A Braced Excavation In Clays And Serviceability Reliability Of Adjacent Buildings, Cheng Liang Hsiao

All Dissertations

The goal of this dissertation research is to establish an improved procedure for evaluating the excavation-induced ground settlement and building serviceability. This research covers several closely related topics. Firstly, a simplified small strain soil model developed by Hsieh et al. (2003), called the Modified Pseudo Plasticity (MPP) model, is evaluated for its capability and performance in the prediction of the excavation-induced ground deformation behavior using Finite Element Method (FEM). Secondly, for the development of the envisioned empirical models for estimating the excavation-induced wall and ground responses, a database of excavation case histories are compiled. To complement the database of excavation …

Dynamic Measurements Of Lubrication Film Thickness Of Uhmwpe Contacts For Total Joint Replacements, Andrew Clark

All Dissertations

A new contact sensing technology previously developed in the Biotribology Laboratory at Clemson University was further studied, evaluated, and characterized to extend its use to the measurement of lubricating film thickness. First, the laboratory's force-controlled knee joint simulator was used while dynamic contact pressure measurements under both dry and lubricated conditions were made using the sensor technology employed in two different artificial knee implant geometries. Each implant was machined by the manufacturer from custom blocks of ultra high molecular weight polyethylene (UHMWPE) containing a grid of discrete sensing regions. The difference between the dry and lubricated contact areas measured at …

A Nationwide Comparison Of Aviation Programs, D. Jason Mcconnell

Undergraduate Honors Capstone Projects

Students considering a college education have many different priorities in mind. When considering a career in aviation after graduation, it brings a whole new set of priorities into the picture. When I was searching for a university degree in aviation I had two major concerns: location and quality of the flight school. Cost was also on my list of concerns but more as a restriction than an option. In other words, I was willing to pay more for the schooling provided it did not get so excessive that I could no longer afford to go. Utah State was among three …

The Effect Of Display Design On Pilot Performance In Controlled Flight Into Terrain Scenarios, Jeremy Charles Smith

Doctoral Dissertations and Master's Theses

New technologies are being developed to prevent the continuing problem of Controlled Flight into Terrain (CFIT) accidents. One such technology, the Synthetic Vision System, seems to hold the solution. While it is readily adapted to the commercial aviation instrument environment, it may not be intuitive enough for the General Aviation private pilot with minimal instrument training. This experiment attempted to examine how pilots of every experience level use and interpret the depiction of synthetic terrain to recognize and avoid potential CFIT situations. The outcome of CFIT was measured against pilot experience and display condition.

Management Of An Intelligent Argumentation Network For A Web-Based Collaborative Engineering Design Environment, Xiaoqing Frank Liu, Man Zheng, Ganesh K. Venayagamoorthy, Ming-Chuan Leu

Computer Science Faculty Research & Creative Works

Conflict resolution is one of the most challenging tasks in collaborative engineering design. In our previous research, a web-based intelligent collaborative system was developed to address this challenge based on intelligent computational argumentation. However, two important issues were not resolved in that system: priority of participants and self-conflicting arguments. In this paper, we develop two methods for incorporating priorities of participants into the computational argumentation network: 1) weighted summation and 2) re-assessment of strengths of arguments based on priority of owners of the argument using fuzzy logic inference. In addition, we develop a method for detection of self-conflicting arguments. Incorporation …

Non-Laser-Based Scanner For Three-Dimensional Digitization Of Historical Artifacts, Donald D. Duncan, Daniel V. Hahn, Kevin C. Baldwin

Electrical and Computer Engineering Faculty Publications and Presentations

A 3D scanner, based on incoherent illumination techniques, and associated data-processing algorithms are presented that can be used to scan objects at lateral resolutions ranging from 5 to 100 m (or more) and depth resolutions of approximately 2 m. The scanner was designed with the specific intent to scan cuneiform tablets but can be utilized for other applications. Photometric stereo techniques are used to obtain both a surface normal map and a parameterized model of the object’s bidirectional reflectance distribution function. The normal map is combined with height information, gathered by structured light techniques, to form a consistent 3D surface. …

Spatial And Temporal Behavior Of Microwave Backscatter Directional Modulation Over The Saharan Ergs, David G. Long, Haroon Stephen

Faculty Publications

Radar backscatter (σ˚) from ergs is modulated with view direction [incidence (θ) and azimuth (φ) angles], where the modulation characteristics reflect the surface geometry. σ˚ also varies spatially and reflects the spatial inhomogeneity of the sand surface. We use σ˚ measurements at different θ and φ angles from the NASA, European Remote Sensing satellite, and SeaWinds scatterometers to understand the relationship between wind and erg bedforms. A model incorporating the σ˚ φ-modulation and spatial inhomogeneity is proposed. Surface slope variations are related to the σ˚ spatial inhomogeneity. We compare the backscatter model results with numerically predicted wind direction data provided …

Vision-Based Landing Of Fixed-Wing Miniature Air Vehicles, Blake Barber, Timothy Mclain, Barrett Edwards

Faculty Publications

This paper outlines a method for using vision-based feedback to accurately land a MAV on a visually identifiable target of approximately known location. The method presented is robust to wind, capable of handling both stationary and moving targets, and capable of cor- recting for camera misalignment, state estimation biases, and parameter estimation biases. Landing results from actual flight tests are presented which demonstrate the effectiveness of the proposed method.

Probabilistic Searching Using A Small Unmanned Aerial Vehicle, Steven R. Hansen, Timothy W. Mclain, Michael A. Goodrich

Faculty Publications

Ground breaking concepts in optimal search theory were developed during World War II by the U.S. Navy. These concepts use an assumed detection model to calculate a detection probability rate and an optimal search allocation. Although this theory is useful in determining when and where search effort should be applied, it offers little guidance for the planning of search paths. This paper explains how search theory can be applied to path planning for an SUAV with a fixed CCD camera. Three search strategies are developed: greedy search, contour search, and composite search. In addition, the concepts of search efficiency and …

Analysis Of The Day Side Equatorial Anomaly, Jayaprabha Shankar

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Equatorial Ionization Anomaly (EIA) is a region of peak plasma density found at ± 10 ◦ to 20 ◦ magnetic latitudes at F-region altitudes. In 2002, NASA launched the Global Ultra Violet Imager (GUVI), which can observe the EIA at various local times, longitudes, and seasons by the glow of the recombining electrons and ions in the plasma. This thesis presents the observations of the geomagnetic quiet time EIA and its global behavior at all local times using 1356 ˚A radiance data from high altitude GUVI limb scans. Limb data is prepared for analysis using reduction techniques that remove from …

A Formal Approach To Specifying And Verifying Spacecraft Behavior, Allan I.S. Mcinnes

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Process algebra can provide spacecraft designers with a mathematical formalism for specifying, understanding, analyzing, and verifying spacecraft system behavior. Although it is standard practice to mathematically model and analyze the subsystems of a spacecraft to ensure that they will function correctly when built, the system-level behavior of the spacecraft is generally understood in much less rigorous terms. This leaves the spacecraft system vulnerable to design errors which may not become apparent until the integration and test phase, when design changes are most expensive. In this dissertation, we develop a formal approach to engineering spacecraft behavior, based on mathematical models of …

Design Of A Low-Power Automatic Wireless Multi-Logger Networking Device, Kelly S. Lewis

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Virtually every industry and discipline (e.g., mining, pharmaceutical, construction, agriculture, reclamation, etc.) is finding applications for wireless data acquisition for monitoring and managing processes and resources. Two sectors, namely agriculture and environmental research, are seeking ways to obtain distributed soil and plant measurements over larger areas like a watershed or large fields rather than a single site of intensive instrumentation (i.e., a weather station). Wireless sensor networks and remote sensing have been explored as a means to satisfy this need. Commercial products are readily available that have remote wireless options to support distributed senor networking. However, these systems have been …

Tropospheric Spectrum Estimations Comparing Maximum Likelihood With Expectation Maximization Solutions And Fast Fourier Transforms, Stanley James Wellard

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The FIRST program (Far Infrared Spectroscopy in the Troposphere) was created as an Instrument Incubator Program (IIP) by NASA Langley to demonstrate improved technology readiness levels (TRLs) for two technologies needed in the design of new imaging Fourier transform spectrometers (IFTS). The IIP IFTS was developed at the Space Dynamics Laboratory and flown to an altitude of 103,000 feet on an instrumented NASA balloon payload. The sensor collected approximately 15,000 interferograms during its 6-hour flight.

Fourier transforms (FFT) produced acceptable results except for noise equivalent temperature differences (NETD) that were five times higher than goal and inconclusive transforms at seven …

Application Of The Relevance Vector Machine To Canal Flow Prediction In The Sevier River Basin, John T. Flake

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This work addresses management of the scarce water resource for irrigation in arid regions where significant delays between the time of order and the time of delivery present major difficulties. Motivated by improvements to water management that will be facilitated by an ability to predict water demand, this work employs a data-driven approach to developing canal flow prediction models using the Relevance Vector Machine (RVM), a probabilistic kernel-based learning machine. Beyond the RVM learning process, which establishes the set of relevant vectors from the training data, a search is performed across model attributes including input set, kernel scale parameter, and …

Langmuir Probe Measurements In The Ionosphere, Aroh Barjatya

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Electric probes have been the primary instruments for the in situ investigation of plasma parameters in the Earth’s ionosphere. This dissertation is a compendium of three papers, each dealing with a separate spacecraft that carried one or more instruments based on the electric probe technique.

The first paper presents data from the Sudden Atom Layer sounding rocket that carried an RF Impedance Probe, a DC fixed-bias Langmuir Probe (DCP), and an Electric Field Probe. The combined dataset indicates a case of payload surface charging, the causes of which are investigated within the paper. A generic circuit model is developed to …

Distributed Cooperative Framework And Algorithms For Wireless Network Performance Optimization, Emily Hong Qi

Dissertations and Theses

In Wireless Local Access Networks (WLANs), the Medium Access Control (MAC) protocol is the primary element that determines the efficiency of sharing the limited communication bandwidth of the wireless channel. IEEE 802.11 MAC uses the contention-based Distributed Coordination Function (DCF) as a fundamental medium access mechanism. However, the dynamic nature of the wireless environment creates mobility challenges of maintaining maximum channel capacity, of obtaining optimal throughput and latency, and of retaining good security in a distributed wireless network.

This dissertation first introduces a set of parameters to characterize the medium status and radio environment, and a mechanism for mobile devices …

An Emotional Mimicking Humanoid Biped Robot And Its Quantum Control Based On The Constraint Satisfaction Model, Quay Williams, Scott Bogner, Michael Kelley, Carolina Castillo, Martin Lukac, Dong Hwa Kim, Jeff S. Allen, Mathias I. Sunardi, Sazzad Hossain, Marek Perkowski

Electrical and Computer Engineering Faculty Publications and Presentations

The paper presents a humanoid robot that responds to human gestures seen by a camera. The behavior of the robot can be completely deterministic as specified by a Finite State Machine that maps the sensor signals to the effector signals. This model is further extended to the constraints-satisfaction based model that links robots vision, motion, emotional behavior and planning. One way of implementing this model is to use adiabatic quantum computer which quadratically speeds-up every constraint problem and will be thus necessary to solve large problems of this type. We propose to use the remotely-connected Orion system by DWAVE Corporation.

Experimental Characterization Of The Outdoor Mimo Wireless Channel Temporal Variation, Michael A. Jensen, Karl F. Warnick, Jon W. Wallace, Ajay Gummalla, Harry B. Lee

Faculty Publications

Time-variant multiple-input multiple-output (MIMO) channels are measured in an outdoor campus environment at 2.45 GHz with directional patch arrays and omnidirectional monopole arrays. A number of useful metrics are proposed for quantifying time variation in MIMO channels: eigenvalue level crossing rate, eigenvector angular deviation, and capacity loss for delayed transmit and receive channel state information (CSI). Measurements in four different environments confirm the strong correlation between angular spread of multipath and MIMO channel time variability. The rate of time variation is also strongly influenced by the type of array, indicating that directional elements may be advantageous for highly mobile environments. …

The Relationship Between Antenna Loss And Superdirectivity In Mimo Systems, Michael A. Jensen, Nicolas W. Bikhazi

Faculty Publications

Multiple-input multiple-output (MIMO) communication systems can theoretically use array superdirectivity to optimally exploit the propagation channel. This superdirectivity leads to very large capacity bounds, particularly when the antennas are closely spaced. However, because superdirective behavior is difficult to achieve in practice, new capacity bounds have been formulated for the case where the level of array superdirectivity is constrained. Existing capacity analyses limit the superdirectivity in a suboptimal way. In this paper, the impact of superdirectivity in the capacity solution is limited by introducing finite ohmic loss in the transmit and receive antenna elements. Computational results reveal that even a small …

A Bayesian Method For Groundwater Quality Monitoring Network Analysis, Khalil A. Ammar

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Water resources management is best done when an efficient and reliable information system is available that provides data about the state of the water system being managed. Herein, a new methodology is developed and demonstrated that incorporates different aspects of monitoring, including vulnerability assessment, environmental health risk, the value of information, and redundancy reduction in an existing monitoring network. These various objectives reflect a desire for cost- efficiency, while taking into account uncertainty in predictions of groundwater contamination potential. This methodology is presented within an integrated approach to groundwater quality monitoring that includes several multi-objective aspects associated with decisions about …

The History And Dynamics Of The Plasma Impedance Probe, Wayne G. Sanderson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

For over 40 years Utah State University / Space Dynamics Laboratory and their predecessors have built instruments to measure electron density in the ionosphere. These instruments have incrementally improved as new measuring techniques have developed and new technologies have been introduced. This thesis introduces the properties and measurement of electron density in the ionosphere. It maps the instrument advancements from the early radio frequency probes of the 1960's to the present Plasma Impedance Probe (PIP), with emphasis on the introduction of the phase lock looped Plasma Frequency Probe (PFP) and the rediscovery of the Swept Impedance Probe (SIP). The current …

Autonomous Landing Of Miniature Aerial Vehicles, D. Blake Barber, Stephen R. Griffiths, Timothy W. Mclain, Randal W. Beard

Faculty Publications

This paper outlines an approach for automated landing of miniature aerial vehicles (MAVs). A landing algorithm defining the landing flight path as a function of height above ground, and the control strategies for following the path, are described. Two methods are presented for estimating height above ground, one based on barometric pressure measurements and the other utilizing optic-flow measurements. The development of an optic-flow sensor and associated sampling strategies are described. Utilizing estimates of height above ground from barometric pressure and optic-flow measurements, repeated landings were performed with a 1.5 m wingspan MAV. With height above ground estimated from barometric …

An Overview Of Mav Research At Brigham Young University, Timothy W. Mclain, Randal W. Beard, D. Blake Barber, Nathan B. Knoebel

Faculty Publications

This paper summarizes research efforts at Brigham Young University related to the control of miniature aerial vehicles (MAVs). Recent results in the areas of vector field path following, precision landing and target prosecution, target localization, obstacle detection and avoidance, tailsitter aircraft control, and cooperative control are presented.

Nevada Risk Assessment/Management Program (Nramp) – Phase 2: Quarterly Progress Report January 1, 2007 Through March 31, 2007, Klaus J. Stetzenbach

Nevada Risk Assessment/Management Program

Work conducted in this second quarter consisted of continuing the detailed data and information acquisition; review of the received document contents, and interpretation of significance in light of previous DOE documents. This included telephone and in-person discussions with DOE NVO personnel at the March Waste Management Symposia in Tucson. As a result of these discussions and review of the supporting data and methodologies, a more specific listing of activities was developed, and DOE provided a confirmatory note to HRC in March.

Much of the review of the received information does indicate significant changes in data, methodologies, and baseline assumptions over …

Final Report: Shf Channel Modeling Over Sea-Based Test Ranges, Qiang Lei, Michael D. Rice

Faculty Publications

This work was supported by the Science & Technology Test & Evaluation Spectrum Efficient Technologies Program sponsored by the US Air Force under contract F04611-02-C-0020. Channel sounding data collected from an airborne transmitter over the Pacific Ocean off the coast of Pt. Mugu, Naval Air Station, was analyzed and used to model multipath propagation over the ocean. The experiments showed that at 8.000 GHz, over the water multipath propagation is well modeled by a three-ray propagation model. The first ray (or propagation path) is the line-of-sight propagation path. The second ray is a strong specular reflection determined by the geometry …

High Temperature Heat Exchanger Project: Quarterly Progress Report January 1, 2007 Through March 31, 2007, Anthony Hechanova

Publications (NSTD)

• The variation of sulfur dioxide production (throughput) of the baseline design of the Ceramatec sulfuric acid decomposer with total mass flow rate of reacting flow has been calculated. According to the calculations, the sulfur dioxide production increases as the total mass flow rate of reacting flow increases regardless of the fact that decomposition percentage of sulfuric trioxide decreases. A parametric study of the baseline design of the Ceramatec sulfuric acid decomposer was performed.

• The thermal performance using various channel geometries for the decomposer was studied. The baseline design (straight channels) has 89.5% thermal efficiency while the thermal efficiency …

Closing The Gap: Getting Full Performance From Residential Central Air Conditioners, Task 4 - Develop New Climate-Sensitive Air Conditioner, Simulation Results And Cost Benefit Analysis, Florida Solar Energy Center, Hugh Henderson, Jr.

FSEC Energy Research Center®

This study evaluated the impacts of conventional and advanced cooling and dehumidification equipment on residential indoor humidity levels and annual energy consumption using whole building computer simulations. The life-cycle cost premium for the various advanced systems was also estimated. Building models were developed for a standard HERS Reference house, meant to represent current residential construction practice, and a High-Efficiency house that would likely qualify for a federal tax credit. The different houses were simulated in seven southeastern U.S. cities and with two ventilation/infiltration scenarios: 1) variable or natural infiltration alone, and 2) mechanical ventilation that complied with ASHRAE Standard 62.2-2004. …

Mitigating The Impacts Of Uncontrolled Air Flow On Indoor Environmental Quality And Energy Demand In Non-Residential Buildings, Florida Solar Energy Center, Hugh Henderson, Jr.

FSEC Energy Research Center®

This project builds on previous field research in Florida that has demonstrated the significant impact that uncontrolled air flows (UAFs) have on indoor environmental quality (IEQ) and energy use in small commercial buildings, a large but poorly understood segment of the nation's building stock. The goal of this project was to extend that research to a national scale by assessing the importance of UAFs in a sample of 25 commercial buildings in New York State. The differences in climate and construction techniques between New York and Florida are expected to bound the range conditions typically found on a national basis. …

Ceas E-News 04.26.2007, College Of Engineering And Applied Sciences

College of Engineering and Applied Sciences News

First-year MAE students sweep awards in AutoCAD contest

On The Formation And Propagation Of Nonlinear Internal Boluses Across A Shelf Break, Subhas K. Venayagamoorthy, Oliver B. Fringer

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

High-resolution two- and three-dimensional numerical simulations are performed of first-mode internal gravity waves interacting with a shelf break in a linearly stratified fluid. The interaction of nonlinear incident waves with the shelf break results in the formation of upslope-surging vortex cores of dense fluid (referred to here as internal boluses) that propagate onto the shelf. This paper primarily focuses on understanding the dynamics of the interaction process with particular emphasis on the formation, structure and propagation of internal boluses on shelf. A possible mechanism is identified for the excitation of vortex cores that are lifted over the shelf break, from …