Engineering Commons^™

Robust And Resilient Control Design And Performance Analysis For Uncertain Systems With Finite Energy Disturbances, Fan Feng

Dissertations (1934 -)

This dissertation addresses the problem of robust and resilient control design with additional performance analysis for uncertain systems with finite energy disturbances. The control design is robust and resilient in the sense of maintaining certain performance criteria in the presence of perturbations in both system parameters and feedback gains. The performance analysis evaluates resilience properties of state feedback and dynamic (state estimate) feedback controllers. A resilient and robust state feedback controller is designed using linear matrix inequality (LMI) techniques for the characterization of solutions to the analysis and design problems posed in this work. Uncertainties are allowed in the linear …

Predicting Multiple Target Tracking Performance For Applications On Video Sequences, Juan Esteban Tapiero Bernal

Dissertations (1934 -)

This dissertation presents a framework to predict the performance of multiple target tracking (MTT) techniques. The framework is based on the mathematical descriptors of point processes, the probability generating functional (p.g.fl). It is shown that conceptually the p.g.fls of MTT techniques can be interpreted as a transform that can be marginalized to an expression that encodes all the information regarding the likelihood model as well as the underlying assumptions present in a given tracking technique. In order to use this approach for tracker performance prediction in video sequences, a framework that combines video quality assessment concepts and the marginalized transform …

Design Optimization Of Permanent Magnet Machines Over A Target Operating Cycle Using Computationally Efficient Techniques, Alireza Fatemi

Dissertations (1934 -)

The common practices of large-scale finite element (FE) model-based design optimization of permanent magnet synchronous machines (PMSMs) oftentimes aim at improving the machine performance at the rated operating conditions, thus overlooking the performance treatment over the entire range of operation in the constant torque and extended speed regions. This is mainly due to the computational complexities associated with several aspects of such large-scale design optimization problems, including the FE-based modeling techniques, large number of load operating points for load-cycle evaluation of the design candidates, and large number of function evaluations required for identification of the globally optimal design solutions. In …

Avalanche Isfet Sensing Chip For Dna Sequencing, Mohammad Uzzal

Electrical and Computer Engineering ETDs

DNA sequencing is a fundamental tool for biological science, aimed primarily at uncovering the genetic contributions to diseases. The first Human DNA sequence, which employed conventional fluorescent-based Sanger Sequencing method, took many years to complete at a cost of over three billion dollars. In one survey, it shows that Human Genome Project (HGP) had generated more than $67 billion in U.S. economic output, $20 billion in personal income for Americans and 310 thousand jobs in USA, only during year 2010. The HGP has increased the need for high-throughput, low cost, fast, accurate and inexpensive DNA sequence technique. This demand has …

Comparison Of Airfoil Precomputational Analysis Methods For Optimization Of Wind Turbine Blades, Ryan Barrett, Andrew Ning

Faculty Publications

The objective of this research was to develop and compare various airfoil precomputational parameterization and analysis techniques for aerostructural optimization of wind turbine blades. The airfoils along the blade were added as optimization design variables through pre-computational parameterization methods using thickness-to-chord ratios and blended airfoil family factors. The airfoils' aerodynamic performance was analyzed with three methods of increasing fidelity: a panel method (XFOIL), Navier-Stokes based computational fluid dynamics (RANS CFD), and wind tunnel data. The optimizations minimized mass over annual energy production (m/AEP) and thereby approximated the minimization of cost of energy. The results were compared to the NREL 5-MW …

Outlier Detection In Complex Categorical Data By Modeling The Feature Value Couplings, Guansong Pang, Longbing Cao, Ling Chen

Research Collection School Of Computing and Information Systems

This paper introduces a novel unsupervised outlier detection method, namely Coupled Biased Random Walks (CBRW), for identifying outliers in categorical data with diversified frequency distributions and many noisy features. Existing pattern-based outlier detection methods are ineffective in handling such complex scenarios, as they misfit such data. CBRW estimates outlier scores of feature values by modelling feature value level couplings, which carry intrinsic data characteristics, via biased random walks to handle this complex data. The outlier scores of feature values can either measure the outlierness of an object or facilitate the existing methods as a feature weighting and selection indicator. Substantial …

Co-Ops And Capstone Design: Are They Interchangeable?, Jay R. Goldberg

Biomedical Engineering Faculty Research and Publications

Many engineering schools in the United States provide opportunities for their undergraduate students to gain practical, real-world experience in their chosen disciplines. Cooperative education is a structured method of combining classroom-based education with practical work experience. A cooperative education experience, commonly known as a co-op, provides academic credit (and pay) for such an experience. Discusses the benefits of these working experiences, focusing on capstone design courses.

Evaluation Of 4h-Sic Photoconductive Switches For Pulsed Power Applications Based On Numerical Simulations, Rajintha Tiskumara

Electrical & Computer Engineering Theses & Dissertations

Since the early studies by Auston, photoconductive semiconductor switches (PCSSs) have been investigated intensively for many applications owing to their unique advantages over conventional gas and mechanical switches. These advantages include high speeds, fast rise times, optical isolation, compact geometry, and negligible jitter. Another important requirement is the ability to operate at high repetition rates with long device lifetimes (i.e., good reliability without degradation). Photoconductive semiconductor switches (PCSSs) are low-jitter compact alternatives to traditional gas switches in pulsed power systems. The physical properties of Silicon Carbide (SiC), such as a large bandgap (3.1-3.35 eV), high avalanche breakdown field (~3 MV/cm), …

Analysis And Implementation Of Communications Systems For Small Satellite Missions, Jason S. Harris

Electrical & Computer Engineering Theses & Dissertations

Nano satellites are becoming more and more popular space platforms due to their relatively low cost. Constellations of many of these small satellites are being launched for scientific and research purposes. This thesis has examined implementing a communications system for small satellites that can be used to maintain constant contact with satellites as they orbit the Earth. It analyzes the various components of a small satellite and how they integrate. It then discusses the different abstraction layers that will be required in order to support the same software architecture across various types of hardware. An orbital analysis was performed to …

Computational Modeling Of Facial Response For Detecting Differential Traits In Autism Spectrum Disorders, Manar D. Samad

Electrical & Computer Engineering Theses & Dissertations

This dissertation proposes novel computational modeling and computer vision methods for the analysis and discovery of differential traits in subjects with Autism Spectrum Disorders (ASD) using video and three-dimensional (3D) images of face and facial expressions. ASD is a neurodevelopmental disorder that impairs an individual’s nonverbal communication skills. This work studies ASD from the pathophysiology of facial expressions which may manifest atypical responses in the face. State-of-the-art psychophysical studies mostly employ na¨ıve human raters to visually score atypical facial responses of individuals with ASD, which may be subjective, tedious, and error prone. A few quantitative studies use intrusive sensors on …

Global Sensitivity Analysis Of Mat Foundation Behavior By Using Finite Element Modeling, Yang Zhao

Civil & Environmental Engineering Theses & Dissertations

Mat foundation is used mostly for high-rise buildings and, since the demand for high- rise buildings is growing, having extensive understanding of mat foundation behavior leads us into more efficient structural design. Mat foundation behaviors are affected mostly by soil’s materials properties, foundation size, and thickness and loading conditions. In this study, the sensitivity of mat foundation structural responses to some of the design parameters are evaluated. Sobol decomposition, which is a variance-based technique, is used to perform the global sensitivity analysis. In this study, Patran, a finite element-based software, is used for modeling and simulations.

Approximate flexible method is …

Development And Implementation Of A Propeller Test Capability For Gl-10 "Greased Lightning" Propeller Design, Brian Edward Duvall

Mechanical & Aerospace Engineering Theses & Dissertations

Interest in small unmanned aerial vehicles has increased dramatically in recent years. Hybrid vehicles which allow forward flight as a fixed wing aircraft and a true vertical landing capability have always had applications. Management of the available energy and noise associated with electric propeller propulsion systems presents many challenges. NASA Langley has developed the Greased Lightning 10 (GL-10) vertical takeoff, unmanned aerial vehicle with ten individual motors and propellers. All are used for propulsion during takeoff and contribute to acoustic noise pollution which is an identified nuisance to the surrounding users. A propeller test capability was developed to gain an …

Detecting And Resolving Air Traffic Conflicts Using A Point Of Closest Approach Method, Marc S. Easton

Mechanical & Aerospace Engineering Theses & Dissertations

A geometrical point of closest approach method is used to solve air traffic conflict detection/resolution problems with a single conflict vehicle that is unaware or unable to aid in resolving the conflict. Nonlinear, three degree of freedom equations of motion for a point-mass vehicle are derived and formulated to allow commanded trajectories to steer the vehicle to a desired location. A dynamic model is developed to propagate the vehicle in three dimensions. A closed-loop model implementing a negative feedback controller using a Proportional-Integral-Derivative control scheme is used to drive the vehicle to match the commanded trajectories. A conflict detection/resolution algorithm …

Machine Learning Methods For Medical And Biological Image Computing, Rongjian Li

Computer Science Theses & Dissertations

Medical and biological imaging technologies provide valuable visualization information of structure and function for an organ from the level of individual molecules to the whole object. Brain is the most complex organ in body, and it increasingly attracts intense research attentions with the rapid development of medical and bio-logical imaging technologies. A massive amount of high-dimensional brain imaging data being generated makes the design of computational methods for efficient analysis on those images highly demanded. The current study of computational methods using hand-crafted features does not scale with the increasing number of brain images, hindering the pace of scientific discoveries …

Extension Of The Gravity Model: A Risk Integrated Approach Towards The Impact Analysis Of Mega Sports Events On Inbound Tourist Arrivals, Abdul Sami Stanekzai

Engineering Management & Systems Engineering Theses & Dissertations

Mega sports events such as the Olympics and the FIFA World Cup are highly attended and countries compete ferociously to host such events due to their perceived long term positive effects. Inbound tourist forecasting is an important aspect of the hosting decision both for the organizing committees and the hosting nations. As a precaution against letting the event fall into incapable hands, which can lead into chaos and mismanagement, measures needs to be taken. Capacity evaluation of interested parties is possible, only by knowing the number of people who may attend the event. However, due to the infrequent occurrence of …

Simulation, Measurement, And Emulation Of Photovoltaic Modules Using High Frequency And High Power Density Power Electronic Circuits, Yunas Erkaya

Electrical & Computer Engineering Theses & Dissertations

The number of solar photovoltaic (PV) installations is growing exponentially, and to improve the energy yield and the efficiency of PV systems, it is necessary to have correct methods for simulation, measurement, and emulation. PV systems can be simulated using PV models for different configurations and technologies of PV modules. Additionally, different environmental conditions of solar irradiance, temperature, and partial shading can be incorporated in the model to accurately simulate PV systems for any given condition.

The electrical measurement of PV systems both prior to and after making electrical connections is important for attaining high efficiency and reliability. Measuring PV …

Design Of Experiments Enhanced Statistical Process Control For Wind Tunnel Check Standard Testing, Ben D. Phillips

Mechanical & Aerospace Engineering Theses & Dissertations

The current wind tunnel check standard testing program at NASA Langley Research Center is focused on increasing data quality, uncertainty quantification and overall control and improvement of wind tunnel measurement processes. The statistical process control (SPC) methodology employed in the check standard testing program allows for the tracking of variations in measurements over time as well as an overall assessment of facility health. While the SPC approach can and does provide researchers with valuable information, it has certain limitations in the areas of process improvement and uncertainty quantification. It is thought by utilizing design of experiments methodology in conjunction with …

Methodologies For Estimating Traffic Flow On Freeways Using Probe Vehicle Trajectory Data, Khairul Azfi Anuar

Civil & Environmental Engineering Theses & Dissertations

Probe vehicle data are increasingly becoming the primary source of traffic data. As probe vehicle data become more widespread, it is imperative that methods are developed so that traffic state estimators such as flow, density, and speed can be derived from such data. In this dissertation three different methodologies are proposed for predicting traffic flow or volume on a freeway. All of the proposed methodologies exploit several different traffic flow theories in conjunction with probe vehicle data to predict traffic flow. The first methodology takes advantage of the fundamental diagram or speed-flow relationship. The relationship states that flow can be …

Applying Newton’S Law Of Cooling When The Target Keeps Changing Temperature, Such As In Stratospheric Ballooning Missions, James Flaten, Kaye Smith, Erick Agrimson

2017 Academic High Altitude Conference

Newton’s Law of Cooling describes how a “small” system, such as a thermometer, comes to thermal equilibrium with a “large” system, such as its environment, as a function of time. It is typically applied when the environment is in thermal equilibrium and the conditions are such that the thermal decay time for the thermometer is a constant. Neither of these conditions are met when measuring environmental (i.e. atmospheric) temperature using a thermometer mounted in a payload lofted into the stratosphere under weather balloons. In this situation the thermometer is in motion so it encounters layer after layer of atmosphere which …

15-12 Analysis Of Walking Facility Performance Guidelines For Individuals With Disabilities, Keith Christensen, Anthony Chen, Mohammad Sadra Sharifi

Transportation Research Center Reports

It is necessary to design and evaluate the effectiveness of walking facilities to accommodate the needs of all pedestrian groups, including individuals with disabilities. The Highway Capacity Manual (HCM) defines walking facility performance using a qualitative measure describing operational conditions, or level of service (LOS). However, how closely pedestrian LOS thresholds correspond to actual conditions are questionable. To overcome the limitations, a controlled large-scaled walking experiment involving individuals with disabilities was conducted at Utah State University (USU). A temporary circuit with the necessary walking facilities was constructed using eight foot self-standing walls. In total, 202 (160 without and 42 with …

14-07 Development Of Decision Support Tools To Assess Pedestrian And Bicycle Safety: Focus On Population, Demographic And Socioeconomic Spectra, Deo Chimba, Abram Musinguzi

Transportation Research Center Reports

Despite the increase of these non-motorized trips, bicyclists and pedestrians remain vulnerable road users that are often over represented in traffic crashes. While the currently used methods that identify hazardous locations serve their purpose well, majority represent a reactive approach that seeks improvement after crashes happen. This research addressed these issues and proposed decision support tools to aid the implementation of bicycle and pedestrian safety strategies. This work developed an access based tool to predict the expected number of crashes at different neighborhood levels. This tool combines the traditional methods such as those provided in the Highway Safety manual to …

2015 Electric Vehicle Market Summary And Barriers, Florida Solar Energy Center, David L. Block

FSEC Energy Research Center®

The object of this research report is to present the current market status of plug-in-electric vehicles (PEVs) and to predict their future penetration within the world and U.S. markets. The sales values for 2015 show that China leads in yearly sales at 214,283 (triple increase for 2014) followed by Western Europe at 184,500 vehicles sold. The U.S. is third at 115,262 followed by Japan at 46,339 vehicles. These four countries comprise 95% of the global sales market. The world total of EV sales for 2015 is estimated to be 565,668 up from 315,519 in 2014. This data also shows that …

Enabling Studies To Optimize Biomaterials For The Treatment Of Myocardial Infarction, Eva Adriana Romito

Theses and Dissertations

The canonical mechanism of wound healing is disrupted following a myocardial infarction (MI), manifesting as an unregulated response that negatively impacts left ventricular (LV) function. This mechanism, termed post-MI remodeling, culminates in an outcome that favors progression to a systolic heart failure state and death for the patient. Therapeutic approaches following the occurrence of a MI are designed to modulate the natural remodeling process and mitigate the loss of cardiac function. The mechanics and structure of the healing infarct have been the focus of numerous pre-clinical and clinical investigations, leading to the impending clinical introduction of material injections as a …

Study Of Friction Extrusion And Consolidation, Xiao Li

Theses and Dissertations

Friction extrusion and consolidation was invented by The Welding Institute (Cambridge, UK) in the early 1990’s. It is related to simple extrusion processes with the primary difference being that the extrusion die rotates about the extrusion axis and the die is required to impart substantial deformation to the initially, finely divided charge (like metal waste or chips) in order to consolidate it prior to extrusion. It can produce high quality wire and fully consolidated bulk material from low-cost precursors like metal chips or powders. The advantages lie in that it is a direct method to recycle metal chips or scraps …

Ultra-High Temperature Full Field Deformation Measurements Of Materials Subjected To Thermo-Mechanical Loading: A Dic Based Study, Guillemo A. Valeri Paoli

Theses and Dissertations

Determining the mechanical response of materials at elevated temperatures is a subject of great interest in metal forming, aerospace and aero-engine industries. For example, measurement of the deformation response under tensile loading at high temperatures is crucial for establishing thermomechanical and thermo-physical properties of materials, consequently, determining the reliability of a component or structure exposed to elevated temperatures. In order to predict the behavior of materials at ultra-high temperatures, a novel experimental approach based on Digital Image Correlation (DIC) is proposed and successfully applied to different materials at temperatures ranging from room temperature to 1100˚C. In these studies, a portable …

Engineered Earthen Masonry Structures For Extreme Wind Loads, Mabel Cristina Cuellar-Azcarate

Theses and Dissertations

Stabilized earthen masonry (SEM), which is built with compressed stabilized earthen blocks (CSEB) and mortar, is emerging as a construction system for affordable, sustainable and high-quality dwellings. Compelling features of earthen masonry are local availability of suitable soils, thermal insulation properties, humidity control within healthy ranges, and relatively low carbon footprint. SEM is also appealing for the construction of affordable houses in rural areas and farmlands, where underrepresented and underprivileged groups often live. In fact, the lack of affordable housing is an issue across the United States where low-income families are most affected, often committing more than half of their …

Comparative Analysis Of Current Control Methods For Modular Multilevel Converters, Jordan D. Rogers

Theses and Dissertations

Modular Multilevel Converters (MMCs) are power electronic converters comprised of a series connection of sub-modules. Their modular structure allows for the possibility to design high-voltage converters that are suitable for utility applications due to the modular fail-safe structure with reduced switching frequency requirements. Some areas of interesting research specific to the MMC topology include modulation techniques, control methods, capacitor voltage balancing strategies, and circulating current suppression control. This thesis presents the development of a predictive current control for MMCs that has the benefit of inherently reduced circulating currents within the converter’s phase units. Two other typical MMC current control strategies …

Development Of Pressure Swing Adsorption (Psa) Processor Co2 Capture From Flue Gas, Md. Atikur Rahman

Theses and Dissertations

Reducing the anthropogenic CO2 emissions and lowering the concentration of greenhouse gases in the atmosphere has become one of the most important environmental issues of recent times. To this end, the development of a cost effective pressure swing adsorption (PSA) process, utilizing commercially available 13X zeolite as the adsorbent, is underway to remove and concentrate CO2 in the flue gas of a coal-fired power plant. This systematic development effort has been carried out so far at the bench scale. It has included the following studies that defined and validated this PSA process both experimentally and via a PSA process model. …

Polyphenols As Natural, Dual-Action Therapeutics For Alzheimer's Disease, Kayla M. Pate

Theses and Dissertations

Alzheimer’s disease (AD), the most common form of dementia, is characterized by extracellular plaques in the brain created when monomeric amyloid-β (Aβ) protein aggregates into fibrillar structures. Soluble Aβ aggregates, including oligomers, that form along the reaction pathway are believed to be the primary pathogenic species and have been shown to increase the production of reactive oxygen species (ROS). This upregulation of ROS is one suggested contributing factor of Aβ aggregate cytotoxicity and has proven capable of mediating cell signaling associated with Aβ aggregate-induced cellular responses.

Polyphenols have been suggested as a complimentary AD therapeutic based on epidemiological evidence that …

Numerical Modeling Of Heat Transfer And Material Flow During Friction Extrusion Process, Hongsheng Zhang

Theses and Dissertations

Friction extrusion process is a novel manufacturing process that converts low-cost metal precursors (e.g. powders and machining chips) into high-value wires with potential applications in 3D printing of metallic products. However, there is little existing scientific literature involving friction extrusion process until recently. The present work is to study the heat transfer and material flow phenomena during the friction extrusion process on aluminum alloy 6061 through numerical models validated by experimental measurements.

The first part is a study of a simplified process in which flow of a transparent Newtonian fluid in a cylindrical chamber caused by frictional contact with a …