Engineering Commons^™

Advanced Water Vapor Lidar Detection System, Hani Elsayed-Ali

Electrical & Computer Engineering Faculty Publications

In the present water vapor lidar system, the detected signal is sent over long cables to a waveform digitizer in a CAMAC crate. This has the disadvantage of transmitting analog signals for a relatively long distance, which is subjected to pickup noise, leading to a decrease in the signal to noise ratio.

Generally, errors in the measurement of water vapor with the DIAL method arise from both random and systematic sources. Systematic errors in DIAL measurements are caused by both atmospheric and instrumentation effects. The selection of the on-line alexandrite laser with a narrow linewidth, suitable intensity and high spectral …

Flexural Rigidity Characterization Of Retrofitted Frp Plates, Steven J. Makonis Jr., Stella B. Bondi, Zia Razzaq

Civil & Environmental Engineering Faculty Publications

Presented herein is a procedure and numerical results for flexural rigidity characterization of Fiber Reinforced Polymer (FRP) plates retrofitted with various types of fabrics. The FRP plates were retrofitted with Kevlar® 49 (Aramid), Carbon Fiber (Harness-Satin H5), and Unidirectional Carbon Fiber (T700 Aerospace Grade) fabrics, respectively. The FRP plate flexural rigidity values were calculated with a central finitedifference iterative scheme while utilizing the experimental load-deflection relations based on bending tests. The tests were performed on each plate by applying a concentrated load at the center. A fourth-order partial differential equation of plate equilibrium was adopted to estimate the plate flexural …

A Method For Identifying Personalized Representations In Web Archives, Mat Kelly, Justin F. Brunelle, Michele C. Weigle, Michael L. Nelson

Computer Science Faculty Publications

Web resources are becoming increasingly personalized — two different users clicking on the same link at the same time can see content customized for each individual user. These changes result in multiple representations of a resource that cannot be canonicalized in Web archives. We identify characteristics of this problem by presenting a potential solution to generalize personalized representations in archives. We also present our proof-of-concept prototype that analyzes WARC (Web ARChive) format files, inserts metadata establishing relationships, and provides archive users the ability to navigate on the additional dimension of environment variables in a modified Wayback Machine.

Gpu-Optimized Code For Long-Term Simulations Of Beam-Beam Effects In Colliders, Y. Roblin, V. Morozov, B. Terzić, M. Aturban, D. Ranjan, M. Zubair

Computer Science Faculty Publications

We report on the development of the new code for long-term simulation of beam-beam effects in particle colliders. The underlying physical model relies on a matrix-based arbitrary-order symplectic particle tracking for beam transport and the Bassetti-Erskine approximation for beam-beam interaction. The computations are accelerated through a parallel implementation on a hybrid GPU/CPU platform. With the new code, a previously computationally prohibitive long-term simulations become tractable. We use the new code to model the proposed medium-energy electron-ion collider (MEIC) at Jefferson Lab.

Watershed-Scale Hybrid Stochastic-Deterministic Modeling Framework And Diffused Sources Superpositioning, Ruby Juvah Damalie

Civil & Environmental Engineering Theses & Dissertations

Predicting hydrologic system behavior is imperative to planning and management of water resources. The study developed an integrated hybrid stochastic and deterministic framework to improve prediction accuracy for overland flow and diffused sources in a watershed. The methodology includes sampling input parameters at system level and contribution of nonpoint source from hydrologically disconnected areas (heretofore referred to as system-level approach and superpositioning respectively). System-level approach includes the integration of a topography-based sampling grid generalized linear model developed by the study and Monte Carlo methods. The superpositioning method adopts in-stream water quality equation for overland flow pollution estimation.

The system-level approach …

System Governance Analysis Of Complex Systems, Behnido Y. Calida

Engineering Management & Systems Engineering Theses & Dissertations

The purpose of this research was to develop and deploy a systems-based framework for analysis of complex governance systems using a multimethodology research design. Two research gaps motivated this research: (1) lack of an integrated conceptualization of a system governance construct, (2) an absence of studies that consider both the governed and governing systems as well as the emergent interactions that arise from within complex governance systems.

The research focused on three primary questions: (1) What are the distinctive characteristics of governance?; (2) What system-based framework can be developed for analysis of governance in complex systems?, and (3) What results …

A Polymer-Based Microfluidic Device With Electrolyte-Enabled Distributed Transducers (Eedt) For Distributed Load Detection, Peng Cheng

Mechanical & Aerospace Engineering Theses & Dissertations

The capability of detecting distributed static and dynamic loads is indispensable in a wide variety of applications, such as examining anatomical structures of biological tissues in tissue health analysis and minimally invasive surgery (MIS) and determining the texture of an object in robotics. This dissertation presents a comprehensive study of a polymer-based microfluidic device with electrolyte-enabled distributed transducers and demonstrates a new concept on using a single microfluidic device for distributed-load detection, which takes advantage of the low-cost microfluidic fabrication technology and the low modulus and biocompatibility of polymer. The core of the device is a single deformable polymer microstructure …

Communications And Energy-Harvesting In Nanosensor Networks, Michele C. Weigle

Computer Science Presentations

PDF of a powerpoint presentation from the National Science Foundation (NSF) Workshop on Biological Computations and Communications in Boston, Massachusetts, November 9, 2012. Also available on Slideshare.

Inactivation Of Bacterial Opportunistic Skin Pathogens By Nonthermal Dc-Operated Afterglow Atmospheric Plasma, L. C. Heller, C. M. Edelblute, A. M. Mattson, X. Hao, J. F. Kolb

Bioelectrics Publications

AIMS: Multidrug-resistant opportunistic pathogens are clinically significant and require the development of new antimicrobial methods. In this study, Acinetobacter baumannii, Pseudomonas aeruginosa and Staphylococcus aureus cells were exposed to atmospheric plasma on agar plates and in vitro on porcine skin for the purpose of testing bacterial inactivation.

METHODS AND RESULTS: Microbial inactivation at varying exposure durations was tested using a nonthermal plasma jet generated with a DC voltage from ambient air. The observed reduction in colony forming units was quantified as log₁₀ reductions.

CONCLUSIONS: Direct plasma exposure significantly inactivated seeded bacterial cells by approx. 6 log_{10 …}

Fault Detection System For Solar Tracking Applications, Hareen Sekhar Illa

Electrical & Computer Engineering Theses & Dissertations

Oil, coal and natural gas reserves are being depleted faster than forecasted due to continued increase in demand for energy sources. We need, therefore, to develop renewable energy sources, such as solar, wind, biomass, geothermal, hydro power and tidal energy. In spite of having very high potential, harvesting solar energy has been a challenge because of the relatively low efficiency of solar cells. In the past few years different methods have been developed to increase the efficiency of the photovoltaic (PV) system: (I) improve the efficiency of solar cells (ill use a solar tracking system to increase the received solar …

Biaxial Bending And Lateral-Torsional Instability Of Imperfect Frp I-Beams Including Effects Of Retrofitting, Jodi Marie Knorowski

Civil & Environmental Engineering Theses & Dissertations

This thesis presents the outcome of a theoretical and experimental study of the behavior of Fiber Reinforced Polymer (FRP) I-beams susceptible to lateral-torsional instability or when subjected to biaxial bending. Laboratory experiments involved application of vertical and horizontal static loads to a 4 x 4 x ¼ in. I-beam with various lengths, and the resulting displacement, twist, and strain were recorded. In the vertical direction, the beam was loaded from different reference load heights with respect to the shear center of the beam. The governing biaxial flexure and torsion differential equations were modified to account for the presence of initial …

Semi-Automatic Simulation Initialization By Mining Structured And Unstructured Data Formats From Local And Web Data Sources, Olcay Sahin

Computational Modeling & Simulation Engineering Theses & Dissertations

Initialization is one of the most important processes for obtaining successful results from a simulation. However, initialization is a challenge when 1) a simulation requires hundreds or even thousands of input parameters or 2) re-initializing the simulation due to different initial conditions or runtime errors. These challenges lead to the modeler spending more time initializing a simulation and may lead to errors due to poor input data.

This thesis proposes two semi-automatic simulation initialization approaches that provide initialization using data mining from structured and unstructured data formats from local and web data sources. First, the System Initialization with Retrieval (SIR) …

Design And Comparison Of Immersive Interactive Learning And Instructional Techniques For 3d Virtual Laboratories, Shuo Ren

Computational Modeling & Simulation Engineering Theses & Dissertations

Virtual reality (VR) as a learning environment plays an important role m engineering education. Utilizing the VR learning environment as a supplement to engineering-based laboratories is especially beneficial for students to prepare for the physical experiment and to grasp the experiment objectives and procedures. Such a methodology can also play a significant role in distance education.

This work presents the methodology design for the physical-to-virtual transformation of two undergraduate mechanical engineering laboratory experiments, namely the "Jet Impact Force on Vanes (Jet Force Lab)" and the "Elastic Test of a Beam in Pure Bending (Beam Bending Lab)" at Old Dominion University. …

Modification And Application Of A Turbulence Response Analysis Method For Flexible Aircraft Configurations, Christie Jeanne Funk

Mechanical & Aerospace Engineering Theses & Dissertations

A software program and associated methodology to study gust loading on aircraft exists for a classification of geometrically simplified flexible configurations. This program consists of a simple aircraft response model with two rigid and three flexible symmetric degrees of freedom and allows for the calculation of various airplane responses due to a discrete one-minus-cosine gust as well as continuous turbulence. Simplifications, assumptions, and opportunities for potential improvements pertaining to the existing software program are first identified, then a revised version of the original software tool is developed with improved methodology to include more complex geometries, additional excitation cases, and output …

Modeling Leakage Currents In Metal Insulator Metal Structures With High K Materials, Priyamvada Maleeswaran

Electrical & Computer Engineering Theses & Dissertations

Various products such as personal computers, cellular phones and mobile devices require high speed and low power consumption. Such improvements have been attained by minimizing physical dimensions of electronic devices, leading to high density integration of transistors and capacitors on integrated chips (]Cs). However, as a consequence of down-scaling device dimensions, tunneling of electrons through thin gate oxides (SiO₂) increases, leading to increased static power leakage. This constitutes wastage in power, and for the case of memory applications necessitates faster refresh cycles. In order to overcome such issues, high-k materials (such as HfO₂ and ZrO₂) …

Configuration Studies Of Electrostatic And Magnetostatic Active Space Radiation Shielding, Trac K. Nguyen

Electrical & Computer Engineering Theses & Dissertations

Developing successful and optimal solutions for mitigating the hazards of radiation in deep space is critical for the success of deep-space long duration explorations, including mission to the Moon, Mars and beyond. A recent report (Tripathi et al., 2008) had explored the feasibility of using electrostatic shielding in conjunction with state-of-the-art materials shielding technologies.

In this thesis research, we study the active electrostatic shielding strategy and examine a hybrid configuration that utilizes both electrostatic and magnetostatic fields. The main advantages of this system are shown to be: (i) much lower magnetic fields that could be below the thresholds set for …

Subnanosecond Exposure Systems For Biological Studies, Jongbong Nah

Electrical & Computer Engineering Theses & Dissertations

The research of bioelectrics has expanded to subnanosecond pulse region and entered a new domain of biophysics of cell interaction with ultra-short and intense electric fields. As subnanosecond pulses may be delivered by antennas to the human body and is very attractive to the medical community, the study of subnanosecond pulse effects calls for exposure systems for both cells and tissues. Two systems were designed in the scope of this thesis, used for cells and tissues respectively. The exposure system designed for cell exposure is a cuvette consisting of two parallel aluminum gaps. This cuvette is placed in a coaxial …

The Factors Behind A Successful Implementation Of Electronic Health Records Systems, Anjee Gorkhali

Engineering Management & Systems Engineering Theses & Dissertations

This research explores the role that budget for Information System (IS) and technical expertise of healthcare service provider staff play on the successful leap from a partial to exhaustive implementation of Electronic Health Records (EHR) Systems. Technical expertise in Information Systems might not be easily measurable directly, but there are a number of indicators that could be used as a proxy, such as: Information System (IS) Department Budget, number of IS staff and the extent of technical trainings provided by the IS department to the clinical staff. This research study hypothesizes that quality technical trainings conducted by an IS department …

Modeling Martian Planetary Entry Descent And Landing Using Monte Carlo Driven Response Surface Methodology, Narcrisha S. Norman

Mechanical & Aerospace Engineering Theses & Dissertations

Response surface methodology (RSM) is a statistical method that explores the relationships between several descriptive variables and one or more response variables. For over sixty years, among other areas, it has been utilized in quality engineering, process engineering, aircraft engineering, economics, chemical engineering, automotive engineering and design/technique optimization. In this dissertation, RSM is utilized to produce regression models that represent the planetary entry, descent and landing (EDL) process. A complete understanding of EDL process is an essential component of any planetary exploration. Research in this area is ongoing and confidence in the ability to explore known celestial bodies is growing. …

Orientation-Invariant Ecg-Based Virtual Pathology Stethoscope Tracking For Standardized Patient Heart Auscultation, Nahom B. Kidane

Computational Modeling & Simulation Engineering Theses & Dissertations

Cardiac auscultation (CA), the act of listening to the heart sounds, is a critical physician's skill that provides substantial information for diagnosing many cardiovascular disorders; therefore, competent training can be a key for accurate and reliable diagnosis. The teaching of CA has been an area of recognized importance since the inception of the stethoscope. However, recent changes in health-care, such as limited student access to patients and higher reliance on competing technologies have made it challenging to teach bedside CA techniques.

Over the past few decades, standardized patients (SPs), individuals trained to portray real patients, have been widely used for …

Nonthermal Plasma Jet Efficacy On Candida Kefyr, Amber Marie Mattson Jackson

Electrical & Computer Engineering Theses & Dissertations

The inactivation abilities of a nonthermal plasma jet were investigated with the yeast C. kefyr, a pathogen with increasing importance in healthcare. The plasma is generated using a microhollow cathode discharge (MHCD) geometry operated with a DC voltage of 2 kV and a current of 30 mA using air as the operating gas at an airflow rate of 8 SLM. The plasma discharge approaches room temperature at a few mm away from the plasma jet allowing for the use on heat sensitive surfaces. Dry air and humid air were used as the operating gas to see if humidity plays …

Efficient Stand-Alone Generalized Inverse Algorithms And Software For Engineering/Sciences Applications: Research And Education, Subhash Chandra Bose S V Kadiam

Civil & Environmental Engineering Theses & Dissertations

Efficient numerical procedures for finding the generalized (or pseudo) inverse of a general (square/rectangle, symmetrical/unsymmetrical, non-singular/singular, real/complex numbers) matrix and solving systems of Simultaneous Linear Equations (SLE) are formulated and explained. The developed procedures and its associated computer software (under MATLAB computer environment) have been based on "special Cholesky factorization schemes" (for a singular matrix), the generalized inverse of the matrix product, and were further enhanced by the Domain Decomposition (DD) formulation.

Test matrices from different fields of applications have been chosen, tested and compared with other existing algorithms. The results of the numerical tests have indicated that the developed …

Identifying Operations Research Systems Analysts' Technical Competencies: A Delphi Approach, William T. Winklbauer

Engineering Management & Systems Engineering Theses & Dissertations

After the attacks of September 11, 2011, the demands for more agile, adaptive, critical-thinking, and multi-talented U.S. Army Operations Research Systems Analysts (FA49s) have only increased. Tomorrow's joint operating environment demands U.S. Army FA49s to be ingenious, proactive, and multi-talented; proficient in their core competencies as military leaders as well as being proficient in their technical competencies as problem solvers in the operations research field.

The purpose of this study was to identify the technical competencies and knowledge, skills, and abilities (KSAs) required for future U.S. Army FA49s to perform their duties within the joint operating environment of the next …

Performance Optimization Over Wireless Links With Operating Constraints, Shiny Abraham

Electrical & Computer Engineering Theses & Dissertations

Wireless communication is one of the most active areas of technological innovations and groundbreaking research ranging from simple cellular phones to highly complex military monitoring devices. The emergence of radios with cognitive capabilities like software defined radios has revolutionized modern communication systems by providing transceivers which can vary their output waveforms as well as their demodulation methods. This adaptability plays a pivotal role in efficient utilization of radio spectrum in an intelligent way while simultaneously not interfering with other radio devices operating on the same frequency band. Thus, it is safe to say that current and future wireless systems and …

Numerical Analysis And Design Optimization Of Organic Bulk Hetero-Junction Solar Cells Using The Mixed Finite Element And Arc-Length Methods, James L. Dean

Mechanical & Aerospace Engineering Theses & Dissertations

Due to the high coupling and non-linear nature of the semiconductor equations, numerical stability becomes a major problem when using a purely Newtonian numerical method in solving these equations. Presented is a robust mixed finite element formulation with application for organic solar cell devices that incorporates the arc-length predictor-corrector method to bypass such stability issues. The simulated device represents a multilayered solar cell using organic bulk hetero-junction materials including donor materials Poly[2,1,3-benzothiadiazole-4,7-diyl[4,4-bis(2-ethylhexyl)-4H-cyclopenta[2,1-b:3,4- b']dithiophene-2,6-diyl]] (PCPDTBT) and poly 3-hexylthiophene (P3HT) with acceptor fullerene materials [6,6]-phenyl C61 butyric acid methyl ester (PC61BM) or [6,6]-phenyl C71 butyric acid methyl ester (PC71BM) as the photoactive …

A Multi-Paradigm Modeling Framework For Modeling And Simulating Problem Situations, Christopher James Lynch

Computational Modeling & Simulation Engineering Theses & Dissertations

Problem situations are problems whose specifications are not universally agreed upon making them a challenge to be modeled and simulated. Models of problem situations depart from the premise of well-defined problems, problems where stakeholders disagree, but also modelers' interpretations play a role in their design and computer implementation.

This thesis proposes a multi-paradigm modeling framework for modeling and simulating problem situations in order to explore the problem space of the problem situations and answer specific modeling questions.

The proposed framework implements the Modeling and Simulation (M&S) System Development Framework (MS-SDF), which is a methodology for modeling a problem situation while …

A Multi-Objective Differential Evolution Algorithm For Engineering Design Optimization, Shantanu S. Muluk

Mechanical & Aerospace Engineering Theses & Dissertations

The current research investigation focuses on the development of a multi-objective global optimizer based on the differential evolution algorithm. A rotationally invariant version of the original differential evolution algorithm is adopted as the core component of the optimization procedure. The optimizer is applied to a number of multi-objective problems: constrained problems, problems of high dimensionality, and problems with non-convex Pareto fronts.

The effectiveness of the proposed optimization framework in real engineering design problems is demonstrated by carrying out an aerodynamic shape optimization of wind turbine airfoils. The investigation focuses on both thin and thick airfoils. The produced Pareto-optimal airfoil shapes …

Meta-Heuristics Analysis For Technologically Complex Programs: Understanding The Impact Of Total Constraints For Schedule, Quality And Cost, Henry Darrel Webb

EMSE Doctoral Projects

Program management data associated with a technically complex radio frequency electronics base communication system has been collected and analyzed to identify heuristics which may be utilized in addition to existing processes and procedures to provide indicators that a program is trending to failure. Analysis of the collected data includes detailed schedule analysis, detailed earned value management analysis and defect analysis within the framework of a Firm Fixed Price (FFP) incentive fee contract.

This project develops heuristics and provides recommendations for analysis of complex project management efforts such as those discussed herein. The analysis of the effects of the constraints on …

Clearing Paths For Emergency Vehicles Using Shock Wave Theory And Vehicle-To-Vehicle Communication, Craig Austin Jordan

Computational Modeling & Simulation Engineering Theses & Dissertations

A new strategy to enable an EV to navigate through congestion at signalized intersections more efficiently has been developed and is presented in this thesis. The proposed strategy involves communicating control messages to vehicles to change their driving behavior and to traffic signals to change their timing plans so that EV s can proceed through congested intersections as quickly as possible. To achieve this, specific vehicles are instructed to hold their positions to create a split in the vehicle queue at a critical location in one lane. The split allows the EV to change lanes and proceed unimpeded at its …

Measurement System Characterization In The Presence Of Measurement Errors, Sean A. Como

Mechanical & Aerospace Engineering Theses & Dissertations

In the calibration of a measurement system, data are collected in order to estimate a mathematical model between one or more factors of interest and a response. Ordinary least squares is a method employed to estimate the regression coefficients in the model. The method assumes that the factors are known without error; yet, it is implicitly known that the factors contain some uncertainty. In the literature, this uncertainty is known as measurement error. The measurement error affects both the estimates of the model coefficients and the prediction, or residual, errors. There are some methods, such as orthogonal least squares, that …