Engineering Commons^™

Parameter Estimation Of The Arterial System, James Charles Carter Ii

Mechanical & Aerospace Engineering Theses & Dissertations

There are a number of disorders that originate from or involve faulty operation of the cardiovascular system. Diseases such as atherosclerosis, diabetes and hypertension can have a debilitating effect on blood flow. This makes the tools for simulating the effects of such diseases on blood flow important. Measures, such as pulse wave velocity, that are generated by models of the cardiovascular system can be important indicators of cardiac health. Although physically measurable, obtaining some parameters comes with a high cost and discomfort to the patient. Models can provide an assessment of many important parameters. The purpose of this project was …

Modeling Geographic Population Dispersion Utilizing Geospatial Information System Environment Agents In An Agent Based Model, Karl D. Liebert

Computational Modeling & Simulation Engineering Theses & Dissertations

New capabilities in agent based model (ABM) environments are opening the door to the creation of ABM that may incorporate high-quality, real world environment data in the form of Geospatial Information System (GIS) files . In the past, GJS environments were only possible through extensive software development efforts focused on specific model applications.

This thesis explores the value and issues of using GIS data to provide an ABM environment. It examines the ability of ABM development environments (DE) to support GIS environment data. The selected ABM DE is then used to model population behavior in an environment defined by authoritative …

Modeling And Stability Analysis Of Nonlinear Sampled-Data Systems With Embedded Recovery Algorithms, Heber Herencia-Zapana

Electrical & Computer Engineering Theses & Dissertations

Computer control systems for safety critical systems are designed to be fault tolerant and reliable, however, soft errors triggered by harsh environments can affect the performance of these control systems. The soft errors of interest which occur randomly, are nondestructive and introduce a failure that lasts a random duration. To minimize the effect of these errors, safety critical systems with error recovery mechanisms are being investigated. The main goals of this dissertation are to develop modeling and analysis tools for sampled-data control systems that are implemented with such error recovery mechanisms. First, the mathematical model and the well-posedness of the …

Using Timed-Release Cryptography To Mitigate Preservation Risk Of Embargo Periods, Rabia Haq

Computer Science Theses & Dissertations

This research defines Time-Locked Embargo, a framework designed to mitigate the Preservation Risk Interval: the preservation risk associated with embargoed scholarly material. Due to temporary access restrictions, embargoed data cannot be distributed freely and thus preserved via data refreshing during the embargo time interval. A solution to mitigate the risk of data loss has been developed by suggesting a data dissemination framework that allows data refreshing of encrypted instances of embargoed content in an open, unrestricted scholarly community. This framework has been developed by exploiting implementations of existing technologies to"time-lock" data using Timed-Release Cryptology (TRC) so that it can be …

Engineering Management Framework In Support Of Modeling & Simulation Application For Domain Specific Procurement, Thomas Guy Litwin

Engineering Management & Systems Engineering Theses & Dissertations

A strategic process is desirable for project-based organizations in order for them to be efficient and effective when developing Modeling & Simulation (M&S) systems. This thesis proposes an overarching process that combines traditional M&S and Engineering Management methodologies in a new framework to support M&S organizations during the procurement process.

This thesis proposes both a Strategic Project Management Process (SPMP) and a systems engineering process for M&S federation development projects. The systems engineering process utilizes the artifacts of Model Driven Architecture (MDA) to support building M&S federations driven by operational requirements. Detailed research of this systems engineering process revealed a …

Reflection High-Energy Electron Diffraction Studies Of Indium Phosphide (100) And Growth On Indium And Indium Nitride On Silicon (100), Mohamed Abd-Elsattar Hafez

Electrical & Computer Engineering Theses & Dissertations

Study of the effects of atomic hydrogen exposure on structure and morphology of semiconductor surfaces is important for fundamental properties and applications. In this dissertation, the electron yield of a hydrogen-cleaned indium phosphide (InP) surface was measured and correlated to the development of the surface morphology, which was monitored by in situ reflection high-energy electron diffraction (RHEED). Atomic hydrogen treatment produced a clean, well-ordered, and (2x4)-reconstructed InP(100) surface. The quantum efficiency, after activation to negative electron affinity, and the secondary electron emission were shown to increase with hydrogen cleaning time. RHEED patterns of low-index InP(100) surface were modified by the …

Integrating Preservation Functions Into The Web Server, Joan A. Smith

Computer Science Theses & Dissertations

Digital preservation of theWorldWideWeb poses unique challenges, different fromthe preservation issues facing professional Digital Libraries. The complete list of a website’s resources cannot be cited with confidence, and the descriptive metadata available for the resources is so minimal that it is sometimes insufficient for a browser to recognize. In short, the Web suffers from a counting problem and a representation problem. Refreshing the bits, migrating from an obsolete file format to a newer format, and other classic digital preservation problems also affect the Web. As digital collections devise solutions to these problems, the Web will also benefit. But the core …

Biology-Inspired Approach For Communal Behavior In Massively Deployed Sensor Networks, Kennie H. Jones

Computer Science Theses & Dissertations

Research in wireless sensor networks has accelerated rapidly in recent years. The promise of ubiquitous control of the physical environment opens the way for new applications that will redefine the way we live and work. Due to the small size and low cost of sensor devices, visionaries promise smart systems enabled by deployment of massive numbers of sensors working in concert. To date, most of the research effort has concentrated on forming ad hoc networks under centralized control, which is not scalable to massive deployments. This thesis proposes an alternative approach based on models inspired by biological systems and reports …

Using Agile Software Development Practices In A Research Oriented Distributed Simulation, Douglas James Mielke

Computational Modeling & Simulation Engineering Theses & Dissertations

Although sometimes controversial, agile methodologies have proven to be a viable choice for some software development projects. Projects suited to agile methodologies are those that involve new technology, have requirements that change rapidly, and are controlled by small, talented teams. Much literature about agile software development leans towards business products and non-government entities. Only a handful of literature resources mention agile software development being used in government contracts and even fewer resources mention research projects. NASA's Airspace and Traffic Operations Simulation (ATOS) is a research oriented simulation that doesn't follow the traditional business project mold. In an effort to gain …

Caffeine Model Identification For Vigilance Performance Prediction, Chun-Hui Huang

Mechanical & Aerospace Engineering Theses & Dissertations

The pharmacodynamics and pharmacokinetics of caffeine have been well characterized. In this study, a caffeine dynamic model is developed to describe its pharmacodynamic effects on vigilance performance. Validated biomathematical models developed to address both individual and group fatigue and alertness in a non-laboratory setting represent a tremendous commercial opportunity. First, a test data set with caffeine effects isolated from circadian and homeostatic effects is created. Then a modeling approach for input and output effects is developed and different model structures for the caffeine effects are considered. Observer/Kalman filter Identification (OKID) algorithm is proposed and developed to identify the caffeine model …

Uncertainty Assessment Of Aircraft Maintenance Times By Using Evidence Theory And Expert Judgment Elicitation, Huseyin Kudak

Engineering Management & Systems Engineering Theses & Dissertations

The goal of this study is to demonstrate the use of the Dempster-Shafer Theory of evidence as a decision aid to predict aircraft maintenance times during wartime operations using expert judgment elicitation. Increased precision in time estimation enables the jet engine aircraft maintenance facility commander to make more accurate decisions for the Air Force's wartime tactical operations allowing the commander to gain a decisive advantage. A questionnaire was designed to elicit judgments from experts in the Aircraft Maintenance Facility (AMF) to investigate maintenance times of the major failure modes (Ignition, Fuel, and Electrical). Results of the expert judgment elicitation were …

Evaluation Of The Applicability Of Jc3iedm Based Information Exchange Standardization Efforts To Link-16 Based Systems, Anthony Devivi

Computational Modeling & Simulation Engineering Theses & Dissertations

Command and Control (C2) systems are critical components in decision-making systems in both the military and civilian domains. These systems act as the data evaluation and dissemination tools for larger Command, Control, Computer, Communication, Intelligence, Surveillance, and Recognizance (C4ISR) systems. Typical C2 systems accept a wide variety of inputs from many sources such as radars, weapons systems, simulators, operators, and other C2 systems. The C2 system processes the input data and presents to the user information with which decisions are made. The C2 system also determines what information should be translated and disseminated to other C2 platforms.

The basis for …

Disassembly Planning And Costing Through Petri Net Approach, Chunhsi Lei

Mechanical & Aerospace Engineering Theses & Dissertations

In the current consumer oriented environment, many new products appear in the market almost on a daily basis. Lured by advertisements and tempted by new product features, customers are constantly purchasing newer products. Acquiring newer products for often leads to throwing out older ones, but it is a totally different story for manufacturers. They need to consider the best way to reuse a product both for economic purposes and for environmental protection. Considerations for them often include: how to minimize total disassembly cost, how to achieve the lowest total disassembly time at each processing step, and how to sort valuable …

Process Study For The Design Of Small-Scale 2 Kelvin Refrigeration Systems, Peter N. Knudsen

Mechanical & Aerospace Engineering Theses & Dissertations

Helium refrigeration at temperatures below 4.5-Kelvin (K), but greater than 0.8-K typically employ a sub-atmospheric process utilizing a vacuum pumping system. These types of helium refrigerators are of keen interest to present and future particle physics programs utilizing super-conducting magnet or radio-frequency technology. As such, there is a need for small scale 2-K helium refrigeration systems (i.e., those that operated below the lambda temperature) in small laboratories and test facilities at this time. This study establishes the key process parameter choices of flow ratio, heat-exchanger size, and supply pressure, and how they influence the overall system performance for various process …

The Application Of Innovative High-Throughput Techniques To Serum Biomarker Discovery, Izabela Debkiewicz Karbassi

Theses and Dissertations in Biomedical Sciences

Time-of-flight mass spectrometry continues to evolve as a promising technique for serum protein expression profiling and biomarker discovery. As seen in our initial SELDI-TOF MS and MALDI-TOF MS profiling study of serum for the assessment of breast cancer risk, many profiling strategies typically employ single chemical affinity beads or surfaces to decrease sample complexity of dynamic fluids like serum. However, most proteins, captured on a particular surface or bead, are not resolved in the lower mass range where mass spectrometers are most effective. To this end we have designed an expression profiling workflow that utilizes immobilized trypsin paramagnetic beads in …

Real-Time Ultrasound Simulation For Medical Training And Standardized Patient Assessment, Bo Sun

Computational Modeling & Simulation Engineering Theses & Dissertations

With the increasing role played by ultrasound in clinical diagnostics, ultrasound training in medical education has become more and more important. The clinical routine for ultrasound training is on real patients; therefore monitored and guided examinations involving medical students are quite time-constrained. Furthermore, standardized patients (SPs), who are increasingly used in medical school for teaching and assessing medical students, need to be augmented. These SPs are typically healthy individuals who can not accurately portray the variety of abnormalities that are needed for training especially when medical examinations involve instrument interactions. To augment SPs in a realistically effective way and also …

Parallel Mpi/Fortran Finite Element Symmetrical/Unsymmetrical Domain Decomposition, Siroj Tungkatara

Civil & Environmental Engineering Theses & Dissertations

MPI/FORTRAN finite element analysis software based on Domain Decomposition (DD) formulas has been developed in this work. Efficient input data storage/data communication schemes, domain partitioning, fast symbolical and numerical sparse assembly, symmetrical/unsymmetrical sparse solver and robust symmetrical/unsymmetrical iterative solvers algorithms are all incorporated into the developed code. Parallel Precondition Conjugated Gradient (PCG) and Flexible Generalized Minimum Residual (FGMRES) are developed. Efficient computational techniques used in the developed code are explained. Numerical performance and the accuracy of the developed code are conducted on acoustic examples with medium to large grid sizes. The results obtained from ODU Wilbur cluster (under parallel processing …

Developing A Repeatable And Reliable Methodology To Determine Return-On-Investment, Mark Cullen Nesselrode

Computational Modeling & Simulation Engineering Theses & Dissertations

The high costs of modern weapons systems, fuel, personnel, and increasing environmental awareness is forcing U.S. forces to rely on simulation for training. Further, the need to train in a robust and theater specific environment is critical to ensure operational readiness immediately upon reaching the combat theater. Finally, the rapidly changing nature of the conflicts, crises, or contingencies in which U.S. forces are involved requires a new approach to training.

The purpose of this research is to develop and demonstrate the feasibility of a methodology that can provide a reliable, consistent method for determining ROI in various forms, focusing on …

Catalytic Wet Air Oxidation Of Mono Azo Dye Orange Ii: Catalyst Selection, Reaction Kinetics, And Modeling, Pinar Ozdural

Civil & Environmental Engineering Theses & Dissertations

Wastewaters generated as byproducts of dyeing processes are not treatable with conventional methods. It has been estimated that among the 900,000 tons of different dyes produced annually in the world, approximately 10–15% are lost in wastewater streams during manufacturing and processing operations. Once in rivers and streams, dyes cause major problems, such as reducing light penetration, or displaying toxic effects on aquatic life. Therefore, it is essential that dyes are removed from wastewaters before being discharged into the environment.

This study focuses on the catalytic wet air oxidation (CWAO) of Orange II, a mono azo dye used in large amounts …

Massive Spatiotemporal Watershed Hydrological Storm Event Response Model (Mhserm) With Time-Lapsed Nexrad Radar Feed, Changqing Song

Civil & Environmental Engineering Theses & Dissertations

Correctly and efficiently estimating hydrological responses corresponding to a specific storm event at the streams in a watershed is the main goal of any sound water resource management strategy. Methods for calculating a stream flow hydrograph at the selected streams typically require a great deal of spatial and temporal watershed data such as geomorphological data, soil survey, landcover, precipitation data, and stream network information to name a few. However, extracting and preprocessing such data for estimation and analysis is a hugely time-consuming task, especially for a watershed with hundreds of streams and lakes and complicated landcover and soil characteristics. To …

Nonlinear Random Response Of Large-Scale Sparse Finite Element Plate Bending Problems, Swati Chokshi

Civil & Environmental Engineering Theses & Dissertations

Acoustic fatigue is one of the major design considerations for skin panels exposed to high levels of random pressure at subsonic/supersonic/hypersonic speeds. The nonlinear large deflection random response of the single-bay panels aerospace structures subjected to random excitations at various sound pressure levels (SPLs) is investigated. The nonlinear responses of plate analyses are limited to determine the root-mean-square displacement under uniformly distributed pressure random loads. Efficient computational technologies like sparse storage schemes and parallel computation are proposed and incorporated to solve large-scale, nonlinear large deflection random vibration problems for both types of loading cases: (1) synchronized in time and (2) …

Design Of A High-Speed Architecture For Stabilization Of Video Captured Under Non-Uniform Lighting Conditions, Ming Zhu Zhang

Electrical & Computer Engineering Theses & Dissertations

Video captured in shaky conditions may lead to vibrations. A robust algorithm to immobilize the video by compensating for the vibrations from physical settings of the camera is presented in this dissertation. A very high performance hardware architecture on Field Programmable Gate Array (FPGA) technology is also developed for the implementation of the stabilization system. Stabilization of video sequences captured under non-uniform lighting conditions begins with a nonlinear enhancement process. This improves the visibility of the scene captured from physical sensing devices which have limited dynamic range. This physical limitation causes the saturated region of the image to shadow out …

Effects Of Leader Relationship Quality (Lmx), Supervisor Support, And Upward Influence In National Science Foundation Industry /University Cooperative Research Centers, Janet L. Bryant

Psychology Theses & Dissertations

The Industry/University Cooperative Research Center (I/UCRC) is a type of partnership between industries and universities supported by the National Science Foundation. These partnerships enable the transfer of leading-edge technology developed in universities to industrial firms. Leadership plays a powerful role in the success of these research partnerships by creating an environment that is conducive to innovation. Directors of I/UCRCs must be able to successfully lead upward, that is, develop and maintain strong relationships with the university administrators to whom they report, to obtain the necessary support to sustain the center and foster innovation. This study uses leader-member exchange (LMX) theory …

Hypersonic Boundary Layer Receptivity To Acoustic Disturbances Over Cones, Kursat Kara

Mechanical & Aerospace Engineering Theses & Dissertations

The receptivity mechanisms of hypersonic boundary layers to free stream acoustic disturbances are studied using both linear stability theory (LST) and direct numerical simulations (DNS). A computational code is developed for numerical simulation of steady and unsteady hypersonic flow over cones by combining a fifth-order weighted essentially non-oscillatory (WENO) scheme with third-order total-variation-diminishing (TVD) Runge-Kutta method. Hypersonic boundary layer receptivity to free-stream acoustic disturbances in slow and fast modes over 5-degree, half-angle blunt cones and wedges are numerically investigated. The free-stream Mach number is 6.0, and the unit Reynolds number is 7.8×106/ft. Both the steady and unsteady solutions are obtained …

Experimental Investigation Of Active Control Of Bluff Body Vortex Shedding, Ilteris Koc

Mechanical & Aerospace Engineering Theses & Dissertations

Mean and fluctuating forces acting on a body are strongly related to vortex shedding generated behind it. Therefore, it is possible to obtain substantial reductions of at least the unsteady forces if vortex shedding is controlled or its regularity is reduced. While conventional active flow control methods are mainly concerned with direct interaction with, and alteration of, the mean flow about a body, modern techniques involve altering existing flow instabilities using relatively small inputs to obtain large-scale changes of mean flows. Aerodynamic flow control may be intended to delay or suppress boundary layer separation through creation of a boundary layer …

Rapid Prototyping For Virtual Environments, Emre Baydogan

Electrical & Computer Engineering Theses & Dissertations

Development of Virtual Environment (VE) applications is challenging where application developers are required to have expertise in the target VE technologies along with the problem domain expertise. New VE technologies impose a significant learning curve to even the most experienced VE developer. The proposed solution relies on synthesis to automate the migration of a VE application to a new unfamiliar VE platform/technology. To solve the problem, the Common Scene Definition Framework (CSDF) is developed, that serves as a superset/model representation of the target virtual world. Input modules are developed to populate the framework with the capabilities of the virtual world …