Electrical and Computer Engineering Commons^™

Spectrum Adaptation In Cognitive Radio Systems With Operating Constraints, Deepak R. Joshi

Electrical & Computer Engineering Theses & Dissertations

The explosion of high-data-rate-demanding wireless applications such as smart-phones and wireless Internet access devices, together with growth of existing wireless services, are creating a shortage of the scarce Radio Frequency (RF) spectrum. However, several spectrum measurement campaigns revealed that current spectrum usage across time and frequency is inefficient, creating the artificial shortage of the spectrum because of the traditional exclusive "command-and-control" model of using the spectrum. Therefore, a new concept of Cognitive Radio (CR) has been emerging recently in which unlicensed users temporarily borrow spectrum from the licensed Primary Users (PU) based on the Dynamic Spectrum Access (DSA) technique that …

Development Of A Fuel Cell Plug-In Hybrid Electric Vehicle And Vehicle Simulator For Energy Management Assessment, Andrew Meintz

Doctoral Dissertations

"This dissertation offers a description of the development of a fuel cell plug-in hybrid electric vehicle focusing on the propulsion architecture selection, propulsion system control, and high-level energy management. Two energy management techniques have been developed and implemented for real-time control of the vehicle. The first method is a heuristic method that relies on a short-term moving average of the vehicle power requirements. The second method utilizes an affine function of the short-term and long-term moving average vehicle power requirements. The development process of these methods has required the creation of a vehicle simulator capable of estimating the effect of …

Modeling Of Novel Coaxial Cable Bragg Grating Sensor By Coupled Mode Theory, Songping Wu

Doctoral Dissertations

"A new sensor based on the novel concept of coaxial cable Bragg grating (CCBG) has been developed for the integrity of civil infrastructure monitoring. In this dissertation work, fundamental research is conducted in sensor modeling and applications, which correspond to the first four papers of the dissertation. A coupled mode theory (CMT) is first applied to establish a physics-based model for CCBG. A numerical solution of the coupled wave equations for CCBG has been derived and validated. As an indicator of sensor sensitivity, the quality factor (Q-factor) of CCBG as a function of sensor structural/material parameters was analytically investigated by …

Editorial, Mauro Forti, Paolo Nistri, Vittal S. Rao

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.

Fault-Tolerant 3d Clock Network, Chiao Ling Lung, Yu Shih Su, Shih Hsiu Huang, Yiyu Shi, Shih Chieh Chang

Electrical and Computer Engineering Faculty Research & Creative Works

Clock tree synthesis is one of the most important and challenging problems in 3D ICs. the clock signals have to be delivered by through-silicon vias (TSVs) to different tiers with minimum skew and latency. While there are a few related works in literature, none of them considers the reliability of TSVs. Accordingly, the failure of any TSV in the clock tree yields a bad chip. the naive solution using double-TSV can alleviate the problem. But the significant area overhead renders it less practical for large designs. in this paper, we propose a novel TSV fault-tolerant unit (TFU) that can provide …

Reducing Dimensionality Of Hyperspectral Data With Diffusion Maps And Clustering With K-Means And Fuzzy Art, Louis Du Plessis, Rui Xu, Steven Damelin, Michael Sears, Donald C. Wunsch

Electrical and Computer Engineering Faculty Research & Creative Works

It is very difficult to analyse large amounts of hyperspectral data. Here we present a method based on reducing the dimensionality of the data and clustering the result in moving toward classification of the data. Dimensionality reduction is done with diffusion maps, which interpret the eigenfunctions of Markov matrices as a system of coordinates on the original dataset in order to obtain an efficient representation of data geometric descriptions. Clustering is done using k-means and a neural network clustering theory, Fuzzy ART (FA). The process is done on a subset of core data from AngloGold Ashanti, and compared to results …

Hierarchical Mission Management, Emad William Saad, John Lyle Vian, Ryan J. Meuth, Donald C. Wunsch

Electrical and Computer Engineering Faculty Research & Creative Works

The different advantageous embodiments further provide a system for hierarchical mission management comprising a number of mission planners, a data processing system, and a communication system. The number of mission planners are associated with a number of agent groups. The data processing system is configured to execute the number of mission planners. The communication system is configured to provide communication between the number of mission planners.

Preserving Useful Info While Reducing Noise Of Physiological Signals By Using Wavelet Analysis, Jeffrey Lam

UNF Graduate Theses and Dissertations

Wavelet analysis is a powerful mathematical tool commonly used in signal processing applications, such as image analysis, image compression, image edge detection, and communications systems. Unlike traditional Fourier analysis, wavelet analysis allows for multiple resolutions in the time and frequency domains; it can preserve time information while decomposing a signal spectrum over a range of frequencies. Wavelet analysis is also more suitable for detecting numerous transitory characteristics, such as drift, trends, abrupt changes, and beginnings and ends of events. These characteristics are often the most important and critical part of some non-stationary signals, such as physiological signals. The thesis focuses …

Design Of A Current Probe For Measuring Ball-Grid-Array Packaged Devices, Tianqi Li

Masters Theses

"A current probe to measure BGA ball currents via magnetic induction has been designed. The probe is manufactured on a 4 layer flex circuit and has been validated by full wave simulations and measurements. The feature size of the probe is very tiny that it almost pushes the limit of flex-circuit technology. Several critical manufacturing problems were happened, and they have been solved now. The probe allows measuring currents of a 1 mm pitch BGA ball directly. Its operating frequency stretched from tens of MHz up to 3GHz. The BGA probe's mutual inductance is approximately 11 pH, and with amplifiers …

Development Of A Graphical User Interface For The Study Of Parallel-Connected Solar Arrays, Nisha Nagarajan

Masters Theses

"For any solar array it is necessary to be able to harness the maximum possible power from it. A new technology is proposed to improve the efficiency of solar arrays and harness maximum potential power as well by connecting the solar panels in parallel. This thesis describes the development of a graphical user interface for the evaluation of this parallel-connected solar array technology and to compare different scenarios for solar arrays to predict the potential power output to decide the best configuration for an application. This is done via several computations and analysis of field data. The first paper describes …

Impact Of Channel Statistics And Correlation On Underwater Acoustic Communication Systems, Jesse Scott Cross

Masters Theses

"Several statistical properties of underwater acoustic channels gathered from experiment data are analyzed. The baseband channel impulse response (CIR) is estimated using a time domain least squares technique with a sliding window applied to the probing sequences. From the CIR estimation, the probability distribution functions (PDFs) of the magnitude, real part, imaginary part, and phase of the CIR are calculated. Gamma, Rayleigh, and compound k distributions are fitted to the magnitude PDF and the fitness of the distributions are calculated with a two-sample Kolmogorov-Smirnov test. Other statistics such as the autocorrelation function, coherence time, and scattering function are evaluated. The …

Multiple-Input Multiple-Output System Simulation For Spinning Vehicles, Samuel James Petersen

Masters Theses

"This paper investigates the performance of a multiple-input multiple-output (MIMO) wireless communication system, when the transmitter is located on a spinning vehicle. In particular, a 2x2 MIMO system is used, with Alamouti coding at the transmitter. Both Rayleigh and Rician statistical models are considered in this paper and are combined with a deterministic spinning model to simulate the channel. The spinning of the transmitting vehicle, relative to the stationary receive antennas causes additional signal fading, and complicates the decoding and channel estimation. The simulated bit error rate is the primary performance metric used. A 4x2 asymmetric Alamouti coding scheme is …

Hybrid Inorganic/Organic Nanostructured Tandem Solar Cells: Simulation And Fabrication Methods, Patrick Michael Boland Jr.

Electrical & Computer Engineering Theses & Dissertations

Organic solar cell technologies continue to be an extremely active area of scientific research. With their promise of providing low-cost, easily-processable, multi-application photovoltaics, these devices could very possibly be the most viable and practical form of renewable energy among many being explored. However, significant technological obstacles remain that must be overcome if this technology is to successfully realize the goal of providing abundant energy while simultaneously reducing dependence on fossil fuel-based sources. Compared with inorganic solar photovoltaics, power conversion efficiencies in organics are still too low to compete economically.

Much research has been accomplished over the past three decades in …

Improving Sli Performance In Optically Challenging Environments, Eric Dedrick

University of Kentucky Doctoral Dissertations

The construction of 3D models of real-world scenes using non-contact methods is an important problem in computer vision. Some of the more successful methods belong to a class of techniques called structured light illumination (SLI). While SLI methods are generally very successful, there are cases where their performance is poor. Examples include scenes with a high dynamic range in albedo or scenes with strong interreflections. These scenes are referred to as optically challenging environments.

The work in this dissertation is aimed at improving SLI performance in optically challenging environments. A new method of high dynamic range imaging (HDRI) based on …

Fabrication And Study Of Molecular Devices And Photovoltaic Devices By Metal/Dielectric/Metal Structures, Bing Hu

University of Kentucky Doctoral Dissertations

A new class of electrodes with nanometer-scale contact spacing can be produced at the edge of patterned metal/insulator/metal this film structures. A key challenge is to produce insulator layers with low leakage current and have pristine metal contacts for controlled molecular contacts. Atomic layer deposition of high quality Al₂O₃ thin films onto Au electrodes was enabled by surface modification with a self-assembled monolayer of -OH groups that react with a monolayer of trimethylaluminum gas source. Ar ion milling was then used to expose the edge of the Au/dielectric/Au structure for molecular electrode contacts. The junctions are characterized …

Floorplan Design And Yield Enhancement Of 3-D Integrated Circuits, Rajeev Kumar Nain

Dissertations and Theses

We have developed a placement-aware 3-D floorplanning algorithm that enables additional wirelength reduction by planning for 3-D placement of logic gates in selected circuit modules during the floorplanning stage. Thus it also bridges the existing gap between 3-D floorplanning and 3-D placement. To reduce the solution space of 3-D floorplanning which is known to be an NP-hard problem, we derive a set of feasibility conditions on the topological representation of a floorplan. In addition, we have designed a fast module packing algorithm that satisfies a set of constraints for placement-aware 3-D floorplanning. Furthermore, we have designed an efficient evolutionary algorithm …

Evaluation Methods For Health Monitoring Of Aerospace Structure Rotary Joints, Sergio Armando Navarro

Open Access Theses & Dissertations

In September 2007, the excessive vibrations played a significant role in the station operation since one of the rotary joints, which provides the station electrical energy, presented an anomaly. The replacement of its bearing components and re-lubrication were necessary to reduce the problem. To avoid a new anomaly, the inspection of the rotary joints performance continues by using the accelerometers data. This thesis presents three new approaches to monitor the vibrations at the International Space Station based on Root-Mean-Square, kurtosis, and Approximate Entropy (ApEn). MATLAB functions and codes were necessary to implement the three monitoring techniques results from the provided …

Modeling Impulse Oscillometry Data: Using Augmented-Ric And Extended-Ric Respiratory Impedance Model Paramaters To Track Pulmonary Health And Disease, Carlos Domingo Ramos Rocha

Open Access Theses & Dissertations

Respiratory diseases are a great health concern. Early detection of disease could greatly improve quality of life and yet the most common pulmonary function test can be an unreliable diagnostic method, especially in the case of children. A reliable method of detecting and assessing small airway impairment could greatly help with timely diagnosis. This research approaches this problem by taking Impulse Oscillometry (IOS) data and its model-derived parameters and assessing their utility in tracking respiratory function and more specifically, small airway function.

This research first describes the use of electric circuits as models to describe lung properties at distinct regions …

Pressure-Dependent Nanoheteroepitaxy Of Cdte On Si(100) And Soi(100) Substrates Using The Close-Spaced Sublimation Technique, Hoong Yan See Tao

Open Access Theses & Dissertations

CdTe is an ideal II-VI semiconductor compound with a direct bandgap energy of 1.53 eV used in solar cells and infrared detector applications [8]. The National Renewable Energy Laboratory (NREL) reported that cadmium telluride (CdTe) thin films solar cells have achieved efficiency of 16.5% and with potential for improvement up to the theoretical value of 29% [14]. The close-spaced sublimation (CSS) method used for solar cell CdTe growth is being tested for selective CdTe nanoheteroepitaxial growth because the CSS method is cost efficient compared to the molecular beam epitaxy (MBE) and metalorganic vapor phase epitaxy (MOVPE) methods. High quality films …

Novel Photovoltaic Device For Targeted Drug Delivery, Sunny S. Ambure

Open Access Theses & Dissertations

Despite decades of research, progress in targeted drug delivery is relatively slow, hampered, in part, by the lack of appropriate mechanisms to deliver anticancer drugs selectively to tumor tissues. Systemic or oral administration can cause severe toxicity, which limits the therapeutic potential of anticancer drugs [1]. Therefore, the most important goal of drug delivery is to minimize the exposure of normal tissues to these drugs while maintaining their therapeutic concentration in tumors.

A photovoltaic cell (PV) is a system that converts lights into electricity as well as induces charge transfer by photovoltaic effect. Motivated by such unique property, we have …