Engineering Commons^™

Central Mechanisms Regulating Pituitary-Adrenal Activity In Infant Guinea Pigs (Cavia Porcellus) During Exposure To Psychological Stressors: Independent And Combined Effects Of Maternal Separation And Novelty, Deborah Suzanne Maken

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Separation from the maternal attachment figure, particularly when it occurs in a novel or threatening environment, reliably increases pituitary-adrenal activity in a number of species, and is thought to increase later susceptibility to psychopathology in humans. However, little is known about the central mechanisms mediating these effects. Therefore, I investigated cortisol and ACTH levels in plasma, corticotropin-releasing factor (CRF) mRNA expression in the hypothalamic paraventricular nucleus (PVN), and c-Fos activity in a circuit [medial amygdala (MeA)- bed nucleus of the stria terminalus (BNST)] thought to drive pituitary-adrenal activity during exposure to psychological stressors, as well as in the PVN. Measurements …

Autopilot Development For An Rc Helicopter, Mark C. Arlinghaus

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The development of an autopilot system for an RC helicopter presents interesting challengesfrom both a hardware and controls standpoint. The system detailed in this thesis utilizes a 13 state Extended Kalman Filter (EKF) to fuse sensor data and provide a position/velocity/attitude estimate. A novel, state of the art hybrid PID/LQR controller is developed and compared with a full state Linear Quadratic Regulator (LQR). The hybrid controller uses a proportional position, PID velocity outer loop coupled with an inner loop LQR for attitude control. The entire system is developed and implemented in hardware to produce a functional autopilot. The unit was …

Semantic And Role-Based Access Control For Data Grid Systems, Vineela Muppavarapu

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A Grid is an integration infrastructure for sharing and coordinated use of diverseresources in dynamic, distributed virtual organizations (VOs). A Data Grid is an architecture for the access, exchange, and sharing of data in the Grid environment. Distributed data resources can be diverse in their formats, schema, quality, access mechanisms, ownership, access policies, and capabilities. In recent years, several organizations have started utilizing Grid technologies to deploy data-intensive and/or computation-intensive applications. As more and more organizations are sharing data resources and participating in Data Grids, the complexity and heterogeneity of the systems is increasing constantly, but their management techniques are …

Genetic Differentiation In Ambystomatid Salamanders Across A Fragmented Landscape, Joseph E. Bartoszek

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It is generally recognized that amphibian populations declining across the globe. Habitat loss is the primary cause of decline. The salamander family Ambystomatidae has experienced significantly more rapid decline than the average for amphibians. Coefficients of Conservatism (CoC) have been developed for amphibians in Ohio. These are based primarily on habitat requirements with high CoCs for amphibians with stringent habitat requirements (e.g. vernal pools associated with large, intact, undisturbed forest), and low CoCs for amphibians with less stringent habitat requirements. Genetic diversity in five species and one hybrid complex of ambystomatid salamander in southwest Ohio were examined and compared to …

Dynamic Kernel Function For High-Speed Real-Time Fast Fourier Transform Processors, Yu-Heng George Lee

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The fast Fourier transform (FFT) plays a critical role in many modern applications, such as acoustics, optics, telecommunications, wireless sensor networks, location sensing, patient monitoring, speech, signal detection, and image processing. The input dynamic range, data throughput rate, frequency resolution, bandwidth, design flexibility, hardware consumption, and power requirements for the various applications are vastly different, leading to significant research focusing on different aspects of FFT performance improvement.

The proposed dynamic kernel function uses an efficient fixed-point numerical representation of the twiddle factor and replaces the cumbersome multipliers with simple shift-and-add operations to enhance the data throughput rate for high-speed wideband …

Development And Evaluation Of A Flexible Framework For The Design Of Autonomous Classifier Systems, Priya Ganapathy

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We have established a modular virtual framework to design accurate, robust, efficient and cost-conscious autonomous target/object detection systems. Developed primarily for image-based detection problems, such as automatic target detection or computer-aided diagnosis, our approach is equally suitable for non-image-based pattern recognition problems. The framework features six modules: 1) the detection algorithm module accepts two-dimensional, spatially-coded sensor outputs; 2) the evaluation module uses our receiver operator characteristic (ROC)-like assessment tool to evaluate and fine-tune algorithm outputs; 3) the fusion module compares outputs combined under various fusion schemes; 4) the classifier selection module exploits the double-fault diversity measure (F2 DM) to identify …

Interfacial Modification Of Microcellular Carbon: Influence Of Ceramic And Carbon Nanotube Coatings, Anil Kumar Karumuri

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Microcellular carbon is an emerging ultra lightweight and efficient thermal management material, which also has great potential as a reinforcement material for selected composites. However, these porous materials exhibit relatively low mechanical properties, and are susceptible to degradation in oxidizing environment. The scope of this research is to investigate surface modification approaches that can address these issues. Two specific objectives were: (1) to develop ceramic coatings to improve the survivability of carbon foams in high temperature applications, and (2) to develop and test modifications that can improve cellular composites involving carbon foam. It was seen that a mixed layer of …

Identifying Structurally Significant Items Using Matrix Reanalysis Techniques, Bhushan M. Kable

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Knowledge of critical structural items for an aircraft structural system is crucial for any risk integrated design and maintenance procedure. These critical items are those whose failure can cause catastrophic damage to the entire structure or result in loss of availability. For example, failure of the fuselage longeron of an F-15 aircraft resulted in the separation of the aircraft cockpit from the rest of the structure, resulting in a complete loss of the aircraft. This is clearly a critical structural item that was identified during the design process but did not have appropriate design, manufacturing, or maintenance controls that could …

Characterization Of Excitatory Amino Acid Neurotransmitters At Motoneuron Synapses Contacting Renshaw Cells, Dannette Shanon Richards

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Motoneurons are among the best studied neurons in the central nervous system. The motoneuron synapses have been well characterized in the periphery where they release acetylcholine at the neuromuscular junction. However excitatory amino acids also seem to be released from motoneuron terminals in the periphery, and centrally at their synapses contacting Renshaw cells. Although excitatory amino acids are suggested to be released from motoneuron synapses it is not known which excitatory amino acids (either aspartate or glutamate) are released, nor is the mechanism for their release known. To examine the presence and mechanism of release for aspartate and glutamate at …

Extracting, Representing And Mining Semantic Metadata From Text: Facilitating Knowledge Discovery In Biomedicine, Cartic Ramakrishnan

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The information access paradigm offered by most contemporary text information systems is a search-and-sift paradigm where users have to manually glean and aggregate relevant information from the large number of documents that are typically returned in response to keyword queries. Expecting the users to glean and aggregate information has lead to several inadequacies in these information systems. Owing to the size of many text databases, search-and-sift is a very tedious often requiring repeated keyword searches refining or generalizing queries terms. A more serious limitation arises from the lack of automated mechanisms to aggregate content across different documents to discover new …

Reduced Order Modeling Methods For Turbomachinery Design, Jeffrey M. Brown

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Design of structural components is constrained by both iteration time and prediction uncertainty. Iteration time refers to the computation time each simulation requires and controls how much design space can be explored given a fixed period. A comprehensive search of the space leads to more optimum designs. Prediction uncertainty refers to both irreducible uncertainties, such as those caused by material scatter, and reducible uncertainty, such as physics-based model error. In the presence of uncertainty, conservative safety factors and design margins are used to ensure reliability, but these negatively impact component weight and design life. This research investigates three areas to …

Expectation-Maximization Optical Tomosynthetic Volume Imaging, Philip M. Hanna

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Optical tomosynthetic imaging of 3-D objects from disparate 2-D images has been limited in the past by a lack of algorithmic enforcement of physical constraints, in particular within-scene obscuration and object self-occlusion. This paper presents a stochastic observation model of a tomosynthetic collection that explicitly includes an obscuration operator that is unknown by the sensor. The expectation-maximization algorithm is used to iteratively estimate the obscuration operator and to reconstruct the 3-D volume of interest. Explicit inclusion of obscuration effects greatly enhances the spatial and spectral accuracy of 3-D results without use of costly post-processing techniques. Performance metrics are introduced and …

Computational And Experimental Investigations Into Aerospace Plasmas, William Thomas Bennett

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Investigations into two different fields of plasma research are presented here. These include the study of ion engine performance and the use of plasma discharges for flow control. In the area of ion engine performance, optimizing electron confinement is the primary goal of this work. The work of prior researchers was expanded through the study of the cathode emission location and the energy of the primary electrons. Cathode position was shown to have minimal effect on confinement length. For electron energy values greater than 20eV the effect on confinement length was also found to be very small. The strength of …

The Effects Of Chronic Hypoxia And Substance P On The Chemosensitive Response Of Individual Nucleus Tractus Solitarius (Nts) Neurons From Adult Rats, Nicole L. Nichols

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The chemosensitive responses of individual nucleus tractus solitarius (NTS) neurons from neonatal rats have been extensively studied, but few studies have examined the chemosensitive responses of NTS neurons from adult rats. In addition, environmental conditions have been used to mimic respiratory diseases/disorders in rats to study how the cellular responses of individual neurons change to regulate breathing during pathological conditions. Lastly, it has been shown that substance P release increases in response to hypoxia from peripheral afferents that primarily terminate in the caudal NTS. We studied the effect of chronic hypoxia (CHx) and substance P on the response to hypercapnia …

Design Of Pulse Output Direct Digital Synthesizer With An Analog Filter Bank, Aditya R. Pothuri

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Over the past two decades frequency synthesizer has progressed from a relatively crystal bank synthesizer to multi-loop phase locked loops. But in recent years direct digital synthesizers (DDS) have witnessed an increase in demand over their analog counterparts. The DDS offers a wide range of advantages over phase locked loops such as high frequency range, fast switching response, and sub-hertz frequency resolution. However, the conventional DDS suffers limitations due to its architecture involving digital-to-analog converter (DAC) and read-only-memory (ROM) with respect to high clock speeds.

The Pulse Output Direct Digital Synthesizer (PODDS) presented in this thesis eliminates the necessity for …

Gps Coarse Acquisition Using The Monobit Fft Algorithm In A Broadband Receiver, John Flynn

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The purpose of this research was to investigate the feasibility of using broadband electronic warfare (EW) receivers for Global Position System (GPS) tracking. These are pulse-oriented receivers, typically with input bandwidths of 1 Ghz or larger, and so by definition do not have the same characteristics and processing of continuous wave (CW) receivers like GPS devices, FM radios, etc. For example, the spectral output of the Fast Fourier Transform (FFT) used in broadband signal processing updates on the frequency of the FFT input sample size, versus a CW receiver which updates on a more continuous basis.

The foundation of this …

Evolutionary Methodology For Optimization Of Image Transforms Subject To Quantization Noise, Michael Ray Peterson

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Lossy image compression algorithms sacrifice perfect imagereconstruction in favor of decreased storage requirements. Modelossy compression schemes, such as JPEG2000, rely upon the discrete wavelet transform (DWT) to achieve high levels of compression while minimizing the loss of information for image reconstruction. Some compression applications require higher levels of compression than those achieved through application of the DWT and entropy coding. In such lossy systems, quantization provides high compression rates at the cost of increased distortion. Unfortunately, as the amount of quantization increases, the performance of the DWT for accurate image reconstruction deteriorates. Previous research demonstrates that a genetic algorithm can …

Mechanisms Of Nickel-Based Coatings For Fretting Wear Mitigation Of Ti6al4v Interfaces, Carl H. Hager Jr.

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Fretting wear is an accumulation of damage that occurs at component interfaces that are subjected to high contact stresses coupled with low amplitude oscillation. The key to fretting wear reduction in metallic contacts is the mitigation of galling at the interface, followed by the control of debris production and the rheology of active wear debris. Once the thin surface species of the metallic interfaces is dispersed, adhesion between the contacting nascent surfaces causes the inception of severe surface deformation and material transfer or removal. This is extremely apparent in the fretting wear of aerospace materials such as titanium alloy and …

Novel Redox And Dna-Dependent Conformational Changes In Human Ku, A Dna-Double Strand Break Repair Protein, Jason Alexander Lehman

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Ionizing radiation (IR) and radiomimetic drugs used in cancer chemotherapy cause DNA double-strand breaks which are repaired by the nonhomologous end joining (NHEJ) pathway. Ku is a heterodimeric protein comprised of 70 and 80 kDa subunits and recognizes free DNA ends. Once Ku is bound to DNA, it binds to the DNA-dependent protein kinase catalytic subunit (DNA-PKcs), and forms a heterotrimeric DNA-PK complex for repair and damage signaling.

We have analyzed the Ku protein using multiple biochemical techniques and uncovered a novel reversible redox change (Andrews, Lehman and Turchi, (2006) JBC 281(19):13596-603). From this data, we hypothesized that a redox-dependent …

Costas Pll Loop System For Bpsk Detection, Rajesh Kumar Keregudadhahalli

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A 2GHz carrier recovery Costas Loop based BPSK detector is designed using CMOS 0.18μm technology. The designed BPSK detector consists of single to differential conversion circuit, phase/frequency detector, Voltage Controlled Oscillator, differential to single conversion circuit, first order loop filter and a third multiplier. Different architectures available for each block have been discussed along with the design methodology adopted. The schematics were simulated in analog design environment.

The Costas loop presented in this work can sense both 0° and 180° phases at its input. Thus the Costas loop carrier recovery circuit overcomes the 180° phase ambiguity presented by the conventional …

Ici Reduction Methods For Mc-Cdma Systems, Meng Wu

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Multi-carrier code-division multiple-access (MC-CDMA) is an important multiple access candidate for 4G wireless communication system. While MC-CDMA provides high performance and high capacity in frequency selective fading channels, it is very sensitive to the signal distortion, especially the Inter Carrier Interference (ICI). We apply self-cancelation and a frequency transmission paradigm to MC-CDMA system to improve the sytem performance in an ICI rich environment. Furthermore, we combine the frequency transmission paradigm FD-MC-CDMA with ICI cancelation. Also, we apply all these three schemes into non-contiguous OFDM and non-contiguous MC-CDMA systems in simple Cognitive Radio communication environments and present the simulation results. Theoretical …

Automotive Battery State-Of-Health Monitoring Methods, Ryan J. Grube

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Effective vehicular power management requires accurate knowledge of battery state, including state-of-charge (SOC) and state-of-health (SOH). An essential functionality of automotive batteries is delivering high power in short periods to crank the engine. A well-known approach to battery SOH monitoring is to infer battery state-of-health from battery impedance or resistance, which is not robust to variation of battery types. The research and development of more reliable battery state-of-health monitoring methods to ensure vehicle start-up ability are presented in this thesis. The methods include a battery cranking voltage based method, a parity-relation based method using battery voltage and cranking current signals, …

Performance Analysis Of Quantitative Bone Measurement With Spiral, Multi-Detector Ct Scanners, Shruti Gupta

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The measure of bone strength and fracture risk assessment is based primarily on bone mineral density (BMD). Computed tomography (CT), a frequently used radiographic technique that provides cross-sectional images, can be used for BMD quantification. Called quantitative computed tomography (QCT), it determines true volumetric density and also differentiates between trabecular and cortical bone. As a result, QCT improves the ability to detect early changes in trabecular BMD accurately and precisely.

The introduction of helical CT for quantitative analysis introduces new complexities. Even though using multi-detector helical CT for BMD assessment is being suggested, a detailed analysis of its validity is …

Information Presentation On Mobile Device For Plant Operations, Raghavendra Rao Polakonda

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Process control and maintenance systems have been used in the petrochemical and refining industry for long time for improving operator performance and workforce efficiency. However, there is a need to integrate these systems with current technological innovations in a systematic and meaningful manner. Advances in mobile computing, sensor technologies, software algorithms, and computational methods provide the possibility for easy access to information anytime-anywhere. The issues associated with retrieving and reviewing this information directly affects the ability to make timely and quality decisions in high stakes environments like a petrochemical plant where time critical decisions are involved. This research investigates the …

New Heuristic And Metaheuristic Approaches Applied To The Multiple-Choice Multidimensional Knapsack Problem, Chaitr Hiremath

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The knapsack problem has been used to model various decision making processes. Industrial applications find the need for satisfying additional constraints and these necessities lead to the variants and extensions of knapsack problems which are complex to solve. Heuristic algorithms have been developed by many researchers to solve the variants of knapsack problems. Empirical analysis has been done to compare the performance of these heuristics. Little research has been done to find out why certain algorithms perform well on certain test problems while not so well on other test problems. There has been little work done to gain knowledge of …

The Development Of A Nonlinear Phase-Lock Loop With Adaptive Gain Control Based On Modern Control Theory, Michael D. Myers

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As the performance of integrated circuits (IC) improve, a more precise clock-signal is needed to regulate their actions. The primary objective of this dissertation is to improve the phase-lock loop (PLL), which is the most common type of clock-generator. A nonlinear phase-lock loop (NPLL) was developed by adding a nonlinear-gain unit to a standard PLL. The NPLL implementation improves performance compared to existing PLLs by demonstrating faster acquisition times and superior jitter performance. The nonlinear-gain is achieved by the use of a fuzzy controller. The fuzzy controller takes in a value and generates outputs based upon the rules that are …

Broad Bandwidth High Resolution Analog To Digital Converters: Theory, Architecture And Implementation, Saiyu Ren

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Analog to digital converters (ADCs) translate analog quantities, which are characteristic of most phenomena in the "real world" to digital language for a variety of applications including information processing, computing, communication and control systems. The performance of the digital signal processing and communication systems is generally limited by the speed and precision of the digital input signal which is achieved at the interface between analog and digital information. The analog to digital converter (ADC) has become a critical component for advanced telecommunication systems. The desire to move the analog to digital interface closer to the sensor has resulted in more …

Risk Based Analysis And Design Af Stiffened Plates, Heather B. Dwire

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The traditional Risk Based Design (RBD) process involves designing a structure based on risk estimates obtained during several iterations of an optimization routine. This approach is computationally expensive for large-scale aircraft structural systems. The main objective of this research is to establish a RBD algorithm and produce RBD plots for stiffened plates. Basic steps to check functionality will be done by first analyzing a flat plate for which closed formed equations are available and then moving to more complex geometries like stiffened plates.

Therefore, the concept of RBD plots that can be used for both structural sizing and risk assessment …

Design And Analysis Of A Mach 3 Dual Mode Scramjet Combustor, Christopher Ryan Corbin

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Low speed operation of a dual mode scramjet engine is important to the development of a two stage to orbit reusable launch vehicle. This study investigates the Mach 3 operation of a dual mode scramjet engine. SRGULL, a one-dimensional cycle code for scramjet engines, and VULCAN, a computational fluid dynamics code capable of solving reacting flows, are used in this study. Staged injection is investigated to allow more heat release at a low flight Mach number condition so that more thrust can be achieved and inlet unstart is avoided. The nominal case has one injector located 1.067 meters downstream of …

Improved Structural Health Monitoring Using Random Decrement Signatures, Oleg V. Shiryayev

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Detection of structural damage phenomena such as cracks, delaminations, or loose fasteners is important because it increases safety and may allow significant reduction in operational costs. Many structural health monitoring techniques are based on detecting changes in vibration features obtained from the measured response. The technique presented in this work is based on the random decrement signatures calculated from the random response. No knowledge of input signal is required. Random decrement signatures have been used for damage detection purposes in the past. The significance of this work is that it explores the possibility of identifying the type of damage and …