Engineering Commons^™

Self-Organization In Cathode Boundary Layer Discharges, Nobuhiko Takano

Electrical & Computer Engineering Theses & Dissertations

Cathode boundary layer (CBL) discharge, which has been developed as a UV light source, operates in a direct current between a planar cathode and a ring-shape anode that are separated by a dielectric with an opening of the same diameter as the anode. The nonthermal CBL discharges operate in a medium pressure range down to 30 Torr, emitting excimer radiation when operated with noble gases. The radiant excimer emittance at 172 nm in xenon reaches 1.7 W/cm², and a maximum excimer efficiency of 6 % has been obtained. The high excimer radiant emittance, in addition to low cost …

Radical Impact Of Change In Actions And Confidence Index On Reverse Decision Making An Application Based Study, Swatee Trimbak Paithankar

Engineering Management & Systems Engineering Theses & Dissertations

While making decisions under uncertainty, people are often unaware of the logical approach to form the decision process. It is assumed that collecting details, analyzing and evaluating data is enough to make 'proper' decisions. However, past research in the decision making arena has significantly validated that there exists a class of decision problems which is complex, ill-structured and not defined to the level where decision makers can draw logical conclusions based on existing traditional decision approaches. RDM (reverse decision making), one of the novel approaches of decision making under conditions of uncertainty, has shown potential towards addressing some of these …

Integrating Game Technology And Discrete Event Simulation To Analyze Mass Casualty Scenarios, Jason Loveland

Computational Modeling & Simulation Engineering Theses & Dissertations

In the last 10 years, video games have become complex simulation environments with high resolution 3D graphics enabled by powerhouse rendering engines, multi-player client server networks, user friendly displays and graphical user interface , while remaining relatively inexpensive. There is a critical need for systems engineering analysis and rapid trade studies due to changes in operations caused by current events such as terrorist attacks, asymmetric threats, natural disasters, etc. Modem games provide a unique way to visualize and interact with these complex environments, scenarios, missions, and operations. A discrete event simulator (DES) provides an environment to model system architecture behavior, …

Lazy Preservation: Reconstructing Websites From The Web Infrastructure, Frank Mccown

Computer Science Theses & Dissertations

Backup or preservation of websites is often not considered until after a catastrophic event has occurred. In the face of complete website loss, webmasters or concerned third parties have attempted to recover some of their websites from the Internet Archive. Still others have sought to retrieve missing resources from the caches of commercial search engines. Inspired by these post hoc reconstruction attempts, this dissertation introduces the concept of lazy preservation{ digital preservation performed as a result of the normal operations of the Web Infrastructure (web archives, search engines and caches). First, the Web Infrastructure (WI) is characterized by its preservation …

Channel Management In Heterogeneous Cellular Networks, Mohammad Hadi Arbabi

Computer Science Theses & Dissertations

Motivated by the need to increase system capacity in the face of tight FCC regulations, modem cellular systems are under constant pressure to increase the sharing of the frequency spectrum among the users of the network.

Key to increasing system capacity is an efficient channel management strategy that provides higher capacity for the system while, at the same time, providing the users with Quality of Service guarantees. Not surprisingly, dynamic channel management has become a high profile topic in wireless communications. Consider a highly populated urban area, where mobile traffic loads are increased due to highway backups or sporting events. …

Optimization Methods Of Laser Induced Breakdown Spectroscopy (Libs) And The Self-Absorption Problem, Olodia Ayed Taha Nassef

Electrical & Computer Engineering Theses & Dissertations

Laser Induced Breakdown Spectroscopy (LIBS) is a well-established technique for determining elemental composition. Compared to conventional methods, its ability to analyze solids, liquids, and gases with little or no sample preparation makes it more versatile and ideal for field, multi-element, and in-situ analysis. The method can be certified for analytical applications of interest in environmental monitoring and quality control processes. Previous work has demonstrated that several different experimental parameters (e.g. laser wavelength, repetition rate, interaction geometry, surface conditions) may affect the effective analytical possibilities of the method. Therefore, many studies have been devoted to optimize such parameters in a way …

Self-Assembly And Characterization Of Germanium Quantum Dots On Silicon By Pulsed Laser Deposition, Mohammed S. Hegazy

Electrical & Computer Engineering Theses & Dissertations

Self-assembled Ge quantum dots (QD) are grown on Si(100)-(2×1) by pulsed laser deposition (PLD). In situ reflection-high energy electron diffraction (RHEED) and post-deposition atomic force microscopy (AFM) are used to study the growth dynamics and morphology of the QDs. Several films of different thicknesses were grown at a substrate temperature of 400°C using a Q-switched Nd:YAG laser (λ = 1064 mu, 40 ns pulse width, 23 J/cm2 fluence, and 10 Hz repetition rate). At low film thicknesses, but clusters that are faceted by different planes, depending on their height, are observed after the completion of the wetting layer. With increasing …

Distributed Knowledge Discovery In Large Scale Peer-To-Peer Networks, Sachin Shetty

Computational Modeling & Simulation Engineering Theses & Dissertations

Explosive growth in the availability of various kinds of data in distributed locations has resulted in unprecedented opportunity to develop distributed knowledge discovery (DKD) techniques. DKD embraces the growing trend of merging computation with communication by performing distributed data analysis and modeling with minimal communication of data. Most of the current state-of-the-art DKD systems suffer from the lack of scalability, robustness and adaptability due to their dependence on a centralized model for building the knowledge discovery model. Peer-to-Peer networks offer a better scalable and fault-tolerant computing platform for building distributed knowledge discovery models than client-server based platforms. Algorithms and communication …

Shaken Baby Syndrome: Retinal Hemorrhaging. A Biomechanical Approach To Understanding The Mechanism Of Causation, Steven Alex Hans

Mechanical & Aerospace Engineering Theses & Dissertations

Shaken Baby Syndrome (SBS) is a form of abuse where typically an infant, age six months or less, is held and shaken. There may or may not be direct impact associated with this action. Further, there is very little agreement on the actual mechanism of SBS. Clinical studies are limited in showing the exact mechanism of injury and only offer postulations and qualitative descriptions. SBS has received much attention in the media, has resulted in a great deal of litigation and can be the source of unfounded accusations. Therefore, it is necessary to try to quantify the forces that may …

Adsorption Of Lead (Ii) Ions By Organosilicate Nanoporous Materials, Larry Keith Isaacs

Civil & Environmental Engineering Theses & Dissertations

As-synthesized organosilicate nanoporous (OSNP) materials HMS (hexagonal mesoporous structure) and MCM-41 were used as adsorbents for removal of lead (II) ions in laboratory batch and column studies. Mesoporous organosilicates were prepared from tetraethylorthosilicate (TEOS) and either an ionic (cetyltrimethyl-ammonium) or neutral (dodecylamine) surfactant. Batch reaction distribution coefficients for MCM-41 were K_D = 51.5 L/g (SD = 26.3) at 24 h and K_D = 73.7 L/g (SD = 40.5) at 7 d. OSNP lead (II) ion adsorption increased from pH = 3 until pH ca. 7.5 after which a sharp decrease in adsorption was noted. OSNP materials reflected a …

A Structured Systemic Framework For Software Development, Kevin Macgregor Adams

Engineering Management & Systems Engineering Theses & Dissertations

The purpose of this research was to develop and apply a systems-based framework for the analysis of software development project performance. Software development project performance is measured at the project level; that is, cost, schedule, and product quality that affect the overall project. To date, most performance improvement efforts have been focused on individual processes within the overall software development system. Making improvements to sub-elements, processes, or sub-systems without regard for the overall project is a classic misbehavior entered into by practitioners who fail to use a holistic, systemic approach. Attempts to improve sub-system behavior are at odds with The …

Determining Underlying Characteristics Of Supplier Evaluation Model: A Quantitative Empirical Research, Zeynep Ozlem Ozgun

Engineering Management & Systems Engineering Theses & Dissertations

Rapid changes in the business environment, driven by competitive pressures and business complexity, present challenges that organizations cannot address without the support of their suppliers. In the past decades, performance evaluation factors such as quality, delivery, and price have been widely used by organizations to measure their suppliers' performance. Traditional supplier performance dimensions now considered to be only single dimensional, and not guarantee long term success of an organization. Use of internationally recognized standards and guidelines such as ISO 9000, MBNQA are recommended to be feasible for supplier Quality Management System evaluation in the literature. However, their effectiveness as a …

Micro Synthetic Jets As Effective Actuator, Mehti Koklu

Mechanical & Aerospace Engineering Theses & Dissertations

Synthetic jets have previously been studied as actuators for external macroflow control and recently been proposed for internal microflow applications. Despite the wide variety of the potential applications of synthetic jet actuators, the majority of the studies have been done at macro scales. Furthermore, there has not been any design methodology that addresses the effectiveness of the micro synthetic jet actuators. Bearing these needs in mind, a micro synthetic jet configuration is considered in a microscale environment where Kn number is less than 0.1 and more than 0.001. Flowfields are simulated by solving the compressible Navier-Stokes equations. The wall boundary …

A Risk- And Fuzzy Set-Based Methodology For Advanced Concept Technology Demonstration Military Utility Assessment Design, Thomas James Meyers

Engineering Management & Systems Engineering Theses & Dissertations

The U.S. Department of Defense Advanced Concept Technology Demonstration (ACTD) and derivative, rapid acquisition programs offer timely solutions to critical military needs by assessing the utility of technologies mature enough to be fielded without application of traditional, defense system development processes. Military utility assessments (MUA) are ACTDs' most critical features, but the lack of a standard for identifying assessment criteria tailored to specific demonstrations risks poorly informed acquisition decisions and the military operations those decisions are intended to support.

The purpose of this research was to develop and deploy a methodology for identifying measures of effectiveness integral to advanced concept …

Bactericidal Effects Of Cold Plasma Technology On Geobacillus Stearothermophilus And Bacillus Cereus Microorganisms, Angela Dawn Morris

Dental Hygiene Theses & Dissertations

Non-equilibrium atmospheric pressure plasma, also known as cold plasma, is a state of matter that consists of a mix of neutral and charged particles. Plasma generates chemically reactive species and ultraviolet radiation making them useful in decontamination applications (Kong & Laroussi, 2003). Research regarding the inactivation of gram-positive bacteria, such as Bacillus atrophaeus, by cold plasma has been studied by Laroussi et al. (2003); however, there is limited research regarding the germicidal effectiveness of cold plasma on the microorganisms Geobacillus stearothermophilus and Bacillus cereus. The purpose of this study was to determine if cold plasma technology inactivates heat …

An Exploratory Study Of Iso 9001:2000 Quality Management Systems Using The Iso/Iec 15504 Architecture, Paul Richard Shimp

Engineering Management & Systems Engineering Theses & Dissertations

The purpose of this paper is to provide an exploratory study on the implementation and issues regarding Quality Management Systems as defined by ISO 9001 :2000 using the architecture of ISO/IEC 15504. The recently published ISO/IEC 15504 series of standards provides a framework to assess processes and determine levels of capability. With the use of this framework, the study will focus on the assessment and identification of problem areas requiring focus for continual improvement within an ISO 9001 :2000 quality management system.

The structure of this paper is as follows: Section 1 provides a background discussion of ISO 9001 :2000. …

The Distributed Independent-Platform Event-Driven Simulation Engine Library (Diesel), Reejo Mathew

Electrical & Computer Engineering Theses & Dissertations

The Distributed, Independent-Platform, Event-Driven Simulation Engine Library (DIESEL) is a simulation executive, capable of supporting both sequential and distributed discrete-event simulations. A system level specification is provided along with the expected behavior of each component within DIESEL. This behavioral specification of each component, along with the interconnection and interaction between the different components, provides a complete description of the DIESEL behavioral model. The model provides a considerable amount of freedom for an application developer to partition the simulation model, when building sequential and distributed applications with respect to balancing the number of events generated across different components. It also allows …

Detecting Compromised Nodes In Wireless Sensor Networks, Mary Lisa Mathews

Electrical & Computer Engineering Theses & Dissertations

While wireless sensor networks are proving to be a versatile tool, many of the applications in which they are utilized have sensitive data. Therefore, security is crucial in many of these applications. Once a sensor node has been compromised, the security of the network degrades quickly if measures are not taken to deal with this event. There have been many approaches researched to tackle the issue. In this thesis, an anomaly-based intrusion detection protocol is developed to detect compromised nodes in wireless sensor networks.

The proposed protocol is implemented after the sensors are deployed into the environment in which they …

Uncertainty Assessment In High-Risk Environments Using Probability, Evidence Theory And Expert Judgment Elicitation, Stella Barberis Bondi

Engineering Management & Systems Engineering Theses & Dissertations

The level of uncertainty in advanced system design is assessed by comparing the results of expert judgment elicitation to probability and evidence theory. This research shows how one type of monotone measure, namely Dempster-Shafer Theory of Evidence can expand the framework of uncertainty to provide decision makers a more robust solution space. The issues imbedded in this research are focused on how the relevant predictive uncertainty produced by similar action is measured.

This methodology uses the established approach from traditional probability theory and Dempster-Shafer evidence theory to combine two classes of uncertainty, aleatory and epistemic. Probability theory provides the mathematical …

Molecular Dynamics Simulations To Probe Effects Of Ultra-Short, Very-High Voltage Pulses On Cells, Viswanadham Sridhara

Electrical & Computer Engineering Theses & Dissertations

The use of very high electric fields (∼ 100kV/cm or higher) with pulse durations in the nanosecond range (Ultra-short) has been a very recent development in bioelectrics. Traditionally, the electric field effects have mostly been confined to: (a) low field, long-duration pulses, and (b) focused mainly on electroporation studies. Thus, aspects such as possible field-induced DNA damage, calcium release, alterations in neuro-transmitters, or voltage-gating have generally been overlooked.

Ultra-short, high-field pulses open the way to targeted and deliberate apoptotic cell killing (e.g., of tumor cells). Though experimental data is very useful, it usually yields information on macroscopic variables that is …

Assessment Of Preliminary Design Approaches For Metallic Stiffened Cylindrical Shell Instability Problems, Vicki Owen Britt

Mechanical & Aerospace Engineering Theses & Dissertations

A preliminary design tool for metallic stiffened fuselage cylindrical panels subjected to longitudinal compression has been developed and validated by comparison to test results. Several methodologies for stiffened panel buckling and failure predictions were examined and evaluated. An appropriate level of analysis fidelity was determined for different failure modes and design details. Results from panel tests conducted to verify analytical methods used to design the Gulfstream V aircraft were presented. The panels were representative of four general skin/stringer configurations on the aircraft. Finite Element analyses and standard analytical methods were used to predict panel failure loads. The accuracy of the …

Prediction Of Interference Pathloss Inside Commercial Aircraft Using Modulated Fuzzy Logic And Neural Networks, Madiha Jamil Jafri

Electrical & Computer Engineering Theses & Dissertations

Although several modeling techniques have been used to model indoor radio wave propagation and coupling patterns, to date no efficient model exists that calculates indoor-outdoor radio wave propagations on commercial aircraft. Due to the complexity of an aircraft structure, with the additive introduction of creeping wave phenomenon and unknown back-door propagation values from the exterior aircraft antenna to the avionics bay, numerical modeling approaches using Method of Moments (MoM) or Finite Difference Time Domain (FDTD) prove too complex with limitations. This dissertation presents an expert neuro-fuzzy (NF) model for Interference pathloss (IPL) predictions inside an Airbus 320 (A320) airplane, for …

Modeling And Simulations Of Electrical Breakdown And Thermal Failure In Zinc Oxide And Titanium Dioxide For High-Voltage Dielectric Applications, Guogang Zhao

Electrical & Computer Engineering Theses & Dissertations

The development of transmission lines with higher energy storage capabilities is an important goal for compact pulsed power systems. In this context, ceramic dielectrics are promising candidates from the standpoint of high dielectric constants and breakdown strength. Though such materials look promising, their breakdown response characteristics have not been well studied, nor adequately understood. The electrical response of dielectrics also seems to depend on the internal structure and its granularity. For example, the breakdown strength of nano-crystalline insulators such as titania and zinc oxide have been observed to depend on the internal grain size. In general, the hold-off voltage increases …

Sonic Boom Focusing Prediction And Delta Wing Shape Optimization For Boom Mitigation Studies, Nitin Khasdeo

Mechanical & Aerospace Engineering Theses & Dissertations

Supersonic travel over land would be a reality if new aircraft are designed such that they produce quieter ground sonic booms, no louder than 0.3 psf according to the FAA requirement. An attempt is made to address the challenging goal of predicting the sonic boom focusing effects and mitigate the sonic boom ground over pressure for delta wing geometry.

Sonic boom focusing is fundamentally a nonlinear phenomenon and can be predicted by numerically solving the nonlinear Tricomi equation. The conservative time domain scheme is developed to carry out the sonic boom focusing or super boom studies. The computational scheme is …

Propulsion Enhancement Contributions To The Performance Of Space Launch Vehicles, Russell H. Edwards

Mechanical & Aerospace Engineering Theses & Dissertations

A research effort has been undertaken to investigate critical aspects of launch vehicle performance as affected by variations in specific launch vehicle parameters. The major portion of the study involves liquid propellant systems. However, since solid propellant systems also play a role in today's launch systems, a representative solid-propellant launch vehicle has also been analyzed. The research undertaken determined that the payload capability of a space launch vehicle, or, conversely, the vehicle total liftoff mass, is highly sensitive to the manner in which the space launch vehicle is staged. The research has led to the development and programming of a …

Neighborhood Defined Feature Selection Strategy For Improved Face Recognition In Different Sensor Modalitie, Satyanadh Gundimada

Electrical & Computer Engineering Theses & Dissertations

A novel feature selection strategy for improved face recognition in images with variations due to illumination conditions, facial expressions, and partial occlusions is presented in this dissertation. A hybrid face recognition system that uses feature maps of phase congruency and modular kernel spaces is developed. Phase congruency provides a measure that is independent of the overall magnitude of a signal, making it invariant to variations in image illumination and contrast. A novel modular kernel spaces approach is developed and implemented on the phase congruency feature maps. Smaller sub-regions from a predefined neighborhood within the phase congruency images of the training …

Methodology For Analyzing And Characterizing Error Generation In Presence Of Autocorrelated Demands In Stochastic Inventory Models, Rafael Diaz

Computational Modeling & Simulation Engineering Theses & Dissertations

Most techniques that describe and solve stochastic inventory problems rely upon the assumption of identically and independently distributed (IID) demands. Stochastic inventory formulations that fail to capture serially-correlated components in the demand lead to serious errors. This dissertation provides a robust method that approximates solutions to the stochastic inventory problem where the control review system is continuous, the demand contains autocorrelated components, and the lost sales case is considered. A simulation optimization technique based on simulated annealing (SA), pattern search (PS), and ranking and selection (R&S) is developed and used to generate near-optimal solutions. The proposed method accounts for the …

Power-Aware Design Methodologies For Fpga-Based Implementation Of Video Processing Systems, Hau Trung Ngo

Electrical & Computer Engineering Theses & Dissertations

The increasing capacity and capabilities of FPGA devices in recent years provide an attractive option for performance-hungry applications in the image and video processing domain. FPGA devices are often used as implementation platforms for image and video processing algorithms for real-time applications due to their programmable structure that can exploit inherent spatial and temporal parallelism. While performance and area remain as two main design criteria, power consumption has become an important design goal especially for mobile devices. Reduction in power consumption can be achieved by reducing the supply voltage, capacitances, clock frequency and switching activities in a circuit. Switching activities …

Development Of Fast, Distributed Computational Schemes For Full Body Bio-Models And Their Application To Novel Action Potential Block In Nerves Using Ultra-Short, High Intensity Electric Pulses, Ashutosh Mishra

Electrical & Computer Engineering Theses & Dissertations

An extremely robust and novel scheme for computing three-dimensional, time-dependent potential distributions in full body bio-models is proposed, which, to the best of our knowledge, is the first of its kind. This simulation scheme has been developed to employ distributed computation resources, to achieve a parallelized numerical implementation for enhanced speed and memory capability. The other features of the numerical bio-model included in this dissertation research, are the ability to incorporate multiple electrodes of varying shapes and arbitrary locations. The parallel numerical tool also allows for user defined, current or potential stimuli as the excitation input. Using the available computation …

Analysis Of Ultraviolet Energy Distribution In Uv Disinfection Systems Using Monte Carlo Ray -Trace Method, Khoi Trung Nguyen

Civil & Environmental Engineering Theses & Dissertations

Determination of fluence rate in ultraviolet (UV) disinfection systems is a crucial part in evaluating disinfection efficiency of the systems. A robust Monte Carlo Ray Trace (MCRT) method has been developed to determine fluence rates in three-dimensional space of the systems. This is a statistical sampling method in which millions of random light energy bundles are simulated from the axis of each UV lamp and traced through the system until their energies reduce to a minimum threshold level. Inherent phenomena including refraction through quartz tubes, specular reflection at quartz tube surfaces, and absorption by quartz and water, along with specific …