Engineering Commons^™

High Voltage Dc Converter Systems Modeling, Simulation And Analysis, Manish A. Dalal

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The thesis provides insights into important modeling techniques to model the converter system, machine design, control and power stages and integration of the various sub systems to simulate the system level performance. This innovative modeling and simulation project is very relevant to optimizing the system performance, designing the sub circuits, components selection, predicting the system stability and impulse responses. The thesis presents modeling and simulation of three different 270VDC converter systems and comparing their performances against each other. The 270VDC converter system accepts either Generator 3-phase AC voltages or fixed three voltage source followed by single or dual converter stages …

Fuzzy Logic Control Of A Switched-Inductor Pwm Dc-Dc Buck Converter In Ccm, Terry Kolakowski

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Modern electronics are operating at lower voltages with higher currents, requiring power converters to deliver these requirements efficiently. In this thesis, a switch-inductor buck converter is designed for the required specifications; and for the selected design, component losses and efficiency are calculated. A MATLAB/Simulink model is constructed, and tested in the presence of load and source disturbances to show the converter cannot maintain the desired output voltage when the disturbances are applied.

A fuzzy logic PID controller is designed to regulate the duty cycle of the converter to control the output voltage. Control surfaces are designed for proportional, integral, and …

Dual Mode Scramjet: A Computational Investigation On Combustor Design And Operation, Ryan Timothy Milligan

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Numerical analysis was performed on a Dual-Mode Scramjet isolator-combustor. Preliminary analysis was performed to form a baseline geometry. Another study validated the results of a 2D model compared to a 3D model. Stable combustion was shown at two different flight conditions, M=3.0 and M=2.5. A marginal 5% decrease in stream thrust was shown by introducing a 50/50 mix of methane and ethylene. Based on the results of the preliminary analysis, detailed geometry analysis was performed on the 3D baseline geometry. Adding a new set of cavity feeding injectors increased the overall stream thrust and the equivalence ratio in the cavity. …

Ion Transport Mechanisms During Hyposmotic Regulatory And Isosmotic Apoptotic Volume Decreases In A Human Lens Epithelial Cells Line, Ameet Ajit Chimote

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Living cells maintain constant volume in response to physiological stresses by altering trans-membrane ion, solute and water flow. In the present study, early and late membrane transport changes in human lens epithelial (HLE-B3) cells under hyposmotic and apoptotic stress were compared. Cell potassium (Ki), rubidium (Rbi)-uptake and water content were measured by atomic absorption spectrophotometry and gravimetry, respectively. Intracellular chloride concentration [Cl]i was determined with the fluorescence dye N- (ethoxycarbonylmethyl)-6-methoxyquinolinium bromide (MQAE), during regulatory volume decrease (RVD) after hyposmotic stress and apoptotic volume decrease (AVD) induced by staurosporine (STP), a protein-kinase inhibitor. Cell water increased in hyposmotic balanced salt solution …

Conductance Modulation In Bilayer Graphene Nanoribbons, Kirti Kant Paulla

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Graphene nanoribbons are among the recently discovered carbon nanostructures, with unique characteristics for novel applications. One of the most important features of graphene nanoribbons, from both basic science and application points of view, is their electrical conductivity. In this research, we study the electrical conductance of single and double layer nanoribbons of specified widths and edge geometries. The calculations are carried out using ab initio quantum mechanical simulations for obtaining the optimized atomic configurations of the nanoribbons and their electronic structures. These results are then used to calculate the conductance characteristics via Green's function approach to the Landauer's formalism. We …

Layered Sensing Using Master-Slave Cameras, Donald Rodney Mclemore Jr.

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The objective of this thesis is to demonstrate the layered sensing concept using Master-Slave cameras. The process of 2D camera calibration and several key factors that can present error during such calibration are described. The analysis and results are based on calibration of a pinhole model camera system. The calibration is accomplished using OpenCV software and the results are analyzed using MATLAB software. These results are divided into intrinsic and extrinsic camera parameters. These parameters are then used to determine the position and orientation of the object in the camera coordinate system. This thesis also explores the use of two …

New Formic Acid Fuel Cell Orientations To Reduce The Cost Of Cell Components, John Calvin Holtkamp

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Formic acid fuel cells show the potential of outperforming or replacing direct methanol fuel cells. A number of issues need to be overcome in order for fuel cells, specifically formic acid fuel cells, to be seriously considered for use in small electronic devices. One of the largest issues inhibiting the commercial success of fuel cells is the cost of the components. The catalyst and ion-conducting membrane, key components in a fuel cell, are both expensive. With the current amount of costly materials needed to construct a fuel cell, fuel cells will have limited success in becoming mainstream power sources in …

Human Cognitive Biases And Heuristics In Image Analysis, Mary E. Fendley

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Humans often employ cognitive heuristic principles when making decisions. These cognitive heuristic principles allow the human to simplify the decision making task, and can, by their very nature, lead to deviations, referred to as cognitive biases, which influence the quality of the decisions.

While the role of heuristics and biases have been studied in judgmental decision making tasks, very little research on cognitive heuristics and biases has been done on decision making in complex, dynamic tasks. The research undertaken and discussed herein investigates the existence and impact of cognitive biases in time-critical decision making. To do so, this research uses …

The In Vitro Interactions Between Tubulin And Hiv-1 Rev Require Rev's Multimerization And Arginine-Rich Motifs, Amit Sharma

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Rev is a 13 kDa regulatory HIV protein essential for viral replication. It trans-activates expression of late viral proteins by multimerizing onto target mRNA and promoting their export into the cytoplasm. During attempts to find the solution conditions needed to study Rev structure, Watts et al. (2000) discovered that Rev depolymerizes microtubules (MTs) in vitro through the formation of ringed tubulin intermediates called Rev-tubulin toroids (RTTs). Rev interactions with MTs are specific and are thought to mimic the mechanism of Kinesin-13 proteins, themselves potent MT depolymerases that regulate the assembly of the mitotic spindle. If Rev and Kinesin-13 proteins share …

A Spectroscopic Investigation Of A Surface-Discharge-Mode, Dielectric Barrier Discharge, Scott Alan Stanfield Ii

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The use of aerodynamic actuators, such as leading edge slats, trailing edge flaps, roughing strips and ailerons interact with the air during flight, providing maneuverability for air vehicles. These mechanical devices have many inherent, detrimental attributes, such as space requirements on the wing, added wing weight, second response times, increased drag, and increased airframe vibration, resulting in the production of noise. The potential to eliminate or improve upon these detrimental attributes may be realizable by replacing the current mechanical actuators with plasma actuators. Specifically, the surface-discharge-mode, dielectric barrier discharge (SDBD), plasma actuator has a response time on the order of …

Semantics Enriched Service Environments, Karthik Rajagopal Gomadam

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During the past seven years services centric computing has emerged as the preferred approach to architect complex software. Software is increasingly developed by integrating remotely existing components, popularly called services. This architectural paradigm, also called Service Oriented Architecture (SOA), brings with it the benefits of interoperability, agility and flexibility to software design and development. One can easily add or change new features to existing systems, either by the addition of new services or by replacing existing ones. Two popular approaches have emerged for realizing SOA. The first approach is based on the SOAP protocol for communication and the Web Service …

Using Two Channel Communication To Study Selective Auditory Attention Using Air And Bone Conducted Interfaces, Kutbi Nuruddin Kaliyakuwawala

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The purpose of this study was to evaluate the human capability to use selective auditory attention across the two different hearing pathways, air conduction and bone conduction. Four two channel communication systems were used as a basis for comparison: (1) both channels presented via headphones (left ear and right ear each represent a different channel), (2) two channels presented via loudspeakers placed at 135° and 225°, (3) one channel presented via headphones (both ears) and one channel to bone vibrator (placed at the condoyle), and (4) one channel presented via bone vibrator and one channel via loud speakers (placed at …

The Effects Of Depth And Eccentricity On Visual Search In A Depth Display, George Angelo Reis

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The attribute of depth has been shown to provide saliency or conspicuity for items in a visual search task. Novel displays that present information in real physical depth offer potential benefits. Previous research has studied depth in visual search but depth was mostly realized without real physical separation of display elements. This study aimed to better understand the effects of real physical depth and eccentricity on visual search in a depth display. Through this understanding, we can appropriately utilize this new technology. An experiment was conducted to test four hypotheses regarding how depth, eccentricity, target feature, and screen location would …

Graphical User Interface (Gui) To Study Different Reconstruction Algorithms In Computed Tomography, Shital K. Abhange

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Computed tomography (CT) imaging relies on computational algorithms to reconstruct images from projections gathered from the CT scan. Depending on the scanner geometry, different types of reconstruction algorithms can be used. To study these different types of reconstruction algorithms in a user-friendly way, a software tool was built. The aim of the thesis was to provide a software platform to access a number of previously implemented reconstruction algorithms with ease and minimal knowledge of the reconstruction code. The goal was accomplished by building a Graphical User Interface (GUI) using MATLAB 7.7.0 (R2008b). In addition to creating mathematical objects and invoking …

Small Conductance Calcium-Activated Potassium (Sk) Channels In Mammalian Spinal Motoneurons, Zhihui Deng

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Three homologous small conductance calcium-activated potassium (SK) channel subunits (SK1, SK2, and SK3) are expressed in distinct and overlapping patterns in mammalian central nervous system. SK channels likely mediate the medium afterhyperpolarization (mAHP), which plays an essential role in regulating neuron repetitive firing frequency. In spinal motoneurons (MNs) the mAHP duration is shorter on average in fast (F-type) MNs than that in slow (S-type) MNs. To better understand the molecular basis for mAHP, we determined the expression and sub-cellular distribution of SK channels in normal, axonally-injured, and developing spinal MNs in vivo using immunohistochemistry and quantitative confocal imaging techniques.

SK2 …

Induction Of Socs-1 In Hsv-1-Infected Murine Keratinocytes: A Mechanism Of Inhibition Of Interferon Gamma, Kenneth Gene Frey

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Epidermal cells such as keratinocytes are the major site of Herpes Simplex Virus Type 1 (HSV-1) replication in active primary or recurring herpes infection. In this study, a murine keratinocyte cell line (HEL-30) was shown to be refractory to IFNγ induction of an antiviral state to HSV-1 infection, while IFNγ did induce an antiviral state in a murine fibroblast cell line (L929). Particularly, IFN-gamma and its peptide mimetic protected fibrobasts from viral-induced cytopathic effect while the keratinocytes were destroyed by the infection. Suppressor of cytokine synthesis-1 (SOCS-1) a negative regulator of IFNγ, was hypothesized to be responsible for the refractiveness …

Burst Scheduling, Grooming And Qos Provisioning In Optical Burst-Switched Networks, Yuqi Fan

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The demand of network capacity has been increasing steadily with more users than ever connected to the Internet through broadband access and the popularity of video based applications, such as YouTube. Optical wavelength division multiplexing (WDM) networks are expected to form the next-generation backbone network and to fulfill the insatiable appetite for bandwidth.

Wavelength routed WDM optical networks offer the granularity of switching at a fiber, waveband, or a wavelength level. The finest granularity offered is at a wavelength level by provisioning lightpaths for different clients/services. All-optical packet switching is still deemed technically infeasible and its competitiveness as a backbone …

A Self-Configuring 3-D Body Scanner, David James Holtkamp

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A flexible, self-configuring body scanner is described that is capable of capturing and merging range data from multiple views into a single coordinate system without the use of registration. The scanner uses two disconnected frames with embedded lights to merge the coordinate systems of multiple cameras. The frame also serves in finding the laser plane as the lasers are swept over the surface from multiple locations. Both hardware and software details are presented as well as techniques for automating most aspects of the scanner. A new implicit surface implementation is also described for processing and triangulating the resulting point clouds …

Localization And Surveillance Using Wireless Sensor Network And Pan/Tilt Camera, Pratikkumar U. Desai

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The ever growing challenges in hostile environments, health care and warzone require accurate indoor localization and surveillance. The de facto localization technique using GPS has poor indoor performance due to the complexity of the indoor environment. Other Radio frequency based indoor localization techniques are unable of accurate localization due to multipath fading.

In this thesis, a system consisting of Cricket wireless sensor motes, a camera and a Pan/Tilt gimbal is proposed to solve the indoor localization and surveillance problems. The system is easy to deploy, is cost effective and gives accurate results. The Crickets motes use the Time Difference of …

The Effect Of Variable Gravity On The Cooling Performance Of A Partially-Confined Fc-72 Spray, Travis Edward Michalak

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This thesis discusses the effects of a variable-gravity environment on the performance of a subcooled partially-confined spray. An experiment, consisting of a test chamber, the associated flow loops, and instrumentation, was fabricated and flown on the NASA Reduced-Gravity Testing Platform. This modified KC-135 aircraft followed a parabolic flight path to provide various acceleration levels. The spray chamber contained two opposing nozzles spraying onto Thick Film Resistor (TFR) heaters, which were mounted on insulating glass pedestals. Only the upward facing heater was used during this testing. Thermocouples under the heater in the glass pedestal were used to determine the heater surface …

Application Of Modern Principles To Demand Forecasting For Electronics, Domestic Appliances And Accessories, Gregory Daniel Noble

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Royal Philips is a large scale producer of consumer electronics, personal appliances, lighting, and healthcare appliances. Demand data from 12 Business Units (BU) of Royal Philips was examined in the study; four business units from each of three divisions: DAP, PA, and CE. From the data supplied, different forecast techniques were evaluated to determine which procedure produces the highest quality forecasts. Three forecasting techniques were evaluated using the provided data. The three forecasting techniques evaluated are the exponential smoothing forecasting method, the exponential smoothing with a linear trend forecasting method, and the Winters forecasting method.

The Visual Basic for Applications …

Embryonic And Postnatal Development Of The Neural Circuitry Involved In Motor Control, Valerie Cari Ann Siembab

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The development of locomotion is believed to result from the maturation of the spinal circuits controlling motor output, however little is known about its mechanisms. To shed some light into this process we studied the development of the synaptic connectivity of two spinal inhibitory interneurons. Adult motoneurons are controlled by inhibitory networks that include recurrent and reciprocal inhibition (Pierrot-Deseilligny & Burke, 2005). Each is modulated by different ventral horn spinal interneurons that display synaptic connectivity adapted to their function: Renshaw cells (RCs) mediate recurrent inhibition, receive excitatory inputs from motor axons and inhibit homonymous and synergistic motoneurons; while Ia inhibitory …

Hif-1 Alpha: A Master Regulator Of Trophoblast Differentiation And Placental Development, Kashmira Kulkarni

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Early embryonic development occurs under low oxygen levels. The placenta is an organ transiently formed during pregnancy and plays a crucial role during development of the embryo. Alterations in the placental structure or function have been associated with the pathologies such as preeclampsia in humans. In mammals, the hypoxia inducible factor (HIF) transcription factors have been identified as the major regulators of cellular responses in low oxygen. In the current study, we investigated the effects of low oxygen on the differentiation of trophoblast stem cells, lineage committed trophoblast giant cells and labyrinthine lineage-committed cells. We examined the effects of an …

Output Impedance In Pwm Buck Converter, Gregory A. Cazzell

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In this paper, a method is presented to design a minimum order compensator for a PWM buck converter with voltage-mode control that will reduce the closed-loop output impedance to match a specific transfer function. The transfer function for the compensator is rigorously developed. It is shown that a third-order compensator is sufficient to achieve a closed-loop output impedance represented by a first-order transfer function. The method is applied to an example, in which the hardware of the dc-dc converter is realized and tested to verify compliance to system requirements.

On The Satisfaction Of Modulus And Ambiguity Function Constraints In Radar Waveform Optimization For Detection, Lee Kenneth Patton

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We consider the design of radar systems that are capable of using knowledge of their interference environment to dynamically design transmit waveforms that afford optimum signal-to-interference-plus-noise ratio while satisfying modulus and ambiguity function constraints. We begin by establishing the inextricable nature of modulus constraints in the waveform optimization problem. We then extend the state of the art in waveform optimization to accommodate these constraints. This is done by solving a secondary optimization problem using the method of alternating projections. We demonstrate that this approach can be a computationally efficient alternative to dynamic programming methods. We then consider the multiple-target detection …

Improving Remote Homology Detection Using A Sequence Property Approach, Gina Marie Cooper

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Understanding the structure and function of proteins is a key part of understanding biological systems. Although proteins are complex biological macromolecules, they are made up of only 20 basic building blocks known as amino acids. The makeup of a protein can be described as a sequence of amino acids. One of the most important tools in modern bioinformatics is the ability to search for biological sequences (such as protein sequences) that are similar to a given query sequence. There are many tools for doing this (Altschul et al., 1990, Hobohm and Sander, 1995, Thomson et al., 1994, Karplus and Barrett, …

Integrated Faceted Browser And Direct Search To Enhance Information Retrieval In Text-Based Digital Libraries, Shea-Tinn Yeh

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Browsing and searching are two prominent paradigms in information retrieval. In current digital library implementations, exploratory browsing is sometimes not available as an option. When offered, it is commonly presented as an alphabetical listing of chosen categories depending on the scope of the digital collections. In addition, users have to switch between different information spaces for browsing and searching. This research proposes an information retrieval paradigm of integrated faceted browser and direct search interfaces for text-based digital libraries. Experimental results show that compared to a conventional alphabetical browser, the faceted browser can significantly improve the effectiveness (by 30.8%, p = …

Effective Simulation And Optimization Of A Laser Peening Process, Gulshan Singh

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Laser peening (LP) is a surface enhancement technique that has been applied to improve fatigue and corrosion properties of metals. The ability to use a high energy laser pulse to generate shock waves, inducing a compressive residual stress field in metallic materials, has applications in multiple fields such as turbomachinery, airframe structures, and medical appliances. In the past, researchers have investigated the effects of LP parameters experimentally and performed a limited number of simulations on simple geometries. However, monitoring the dynamic, intricate relationships of peened materials experimentally is time consuming, expensive, and challenging.

With increasing applications of LP on complex …

A Study Of Hardware Efficient Recombination Variants In A Mini Population Genetic Algorithm, Shiva Satya Ramesh Varma Bhupathiraju Venkata

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Evolvable Hardware is an emerging sub-field of evolutionary computation in which evolutionary algorithms are employed to create designs for hardware devices. Recent work has combined continuous time recurrent neural networks with the Mini Population (Minipop) Evolutionary Algorithm to create self-configuring device controllers. Standard Minipop eschews recombination operators due to the belief that they increase the size of an algorithm's on chip implementation without adding significant search power for finding neural network controllers. The focus of this thesis is to challenge that thinking by testing a number of hardware efficient recombination operators against two benchmark problems. We consider variants that recombine …

Design And Performance Analysis Of A Secure Proces-Sor Scan-Sp With Crypto-Biometric Capabilities, Raghudeep Kannavara

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Secure computing is gaining importance in recent times as computing capability is increasingly becoming distributed and information is everywhere. Prevention of piracy and digital rights management has become very important. Information security is mandatory rather than an additional feature. Numerous software techniques have been proposed to provide certain level of copyright and intellectual property protection. Techniques like obfuscation attempt to transform the code into a form that is harder to reverse engineer. Tamper-proofing causes a program to malfunction when it detects that it has been modified. Software watermarking embeds copyright notice in the software code to allow the owners of …