Electrical and Electronics Commons^™

Tonescale Compression For Electroluminescent Display, Michael E. Miller, Christopher J. White

AFIT Patents

A method for controlling an electroluminescent display to produce an image for display that has reduced luminance to reduce burn-in on the display while maintaining visible contrast, includes providing the electroluminescent (EL) display having a plurality of EL emitters, the luminance of the light produced by each EL emitter being responsive to a respective drive signal; receiving a respective input image signal for each EL emitter; and transforming the input image signals to a plurality of drive signals that have a reduced peak frame luminance value but maintains contrast in the displayed image to reduce burn-in by adjusting the drive …

Digital Control Board For Phased Array Antenna Beam Steering In Adaptive Communication Applications, Mayur Bansal

Master's Theses

The application of adaptive communication techniques for mobile communications has attracted considerable interest in the last decade. One example of these techniques is spatial filtering through planar antenna array beam forming.

This thesis describes the development of a digital system that adaptively controls a phased array antenna. The radiating structure of the phased antenna array is tetrahedral-shaped and contains four antenna elements on each of its three faces. The overall system comprises of a digital control board with an external computer interface, an RF control board, and the phased antenna array. The RF controls the main lobe direction on the …

A Clamped Dual-Ridged Waveguide Measurement System For The Broadband, Nondestructive Characterization Of Sheet Materials, Milo W. Hyde Iv, Michael J. Havrilla

Faculty Publications

A novel two-port probe which uses dual-ridged waveguides for the nondestructive, broadband characterization of sheet materials is presented. The new probe is shown to possess approximately 2 to 3 times the bandwidth of traditional coaxial and rectangular/circular waveguide probe systems while maintaining the structural robustness characteristic of rectangular/circular waveguide probe systems. The theoretical development of the probe is presented, namely, by applying Love’s equivalence theorem and enforcing the continuity of transverse fields at the dual-ridged waveguide apertures, a system of coupled magnetic field integral equations is derived. The system of coupled magnetic field integral equations is solved using the method …

Silver Oxide-Graphene Sensor For Hydrogen Peroxide, Austin D. Scherbarth, L Stanciu

The Summer Undergraduate Research Fellowship (SURF) Symposium

A nonenzymatic, amperometric sensor for Hydrogen Peroxide (H₂O₂) was designed by drop coating glassy carbon electrodes (GCEs) with Silver Oxide (Ag₂O). Combining Ag₂O with Graphene Oxide and a polymer, PEDOT, was also attempted in order to increase stability and electrochemical properties. Using metal oxides along with Graphene Oxide for sensors has been done quite a bit, but Ag₂O itself has not been research extensively. So, in order to produce the best H₂O₂ sensor, the configuration of all components had to be optimized. Three different Ag₂O …

Ultrashort Pulse Mode-Locked Lasers For Near-Earth Object Deflection, Grant Bergstue, Luke Burgess, Spencer Cole

Von Braun Symposium Student Posters

No abstract provided.

Analysis And Optimization Of Cooperative Wireless Networks, Phuong Thanh Tran

Open Access Dissertations

Recently, cooperative communication between users in wireless networks has attracted a considerable amount of attention. A significant amount of research has been conducted to optimize the performance of different cooperative communication schemes, subject to some resource constraints such as power, bandwidth, and time. However, in previous research, each optimization problem has been investigated separately, and the optimal solution for one problem is usually not optimal for the other problems.

This dissertation focuses on joint optimization or cross-layer optimization in wireless cooperative networks. One important obstacle is the non-convexity of the joint optimization problem, which makes the problem difficult to solve …

Harmonic Generation In Multiresonant Plasma Films, Maria Antonietta Vincenti, Domenico De Ceglia, Joseph W. Haus, Michael Scalora

Electrical and Computer Engineering Faculty Publications

We investigate second- and third-harmonic generation in a slab of material that displays plasma resonances at the pump and its harmonic frequencies. Near-zero refractive indices and local field enhancement can deplete the pump for kW/cm² incident powers, without resorting to other resonant photonic mechanisms. We show that low-threshold, highly efficient nonlinear processes are possible in the presence of losses and phase mismatch in structures that are 10⁴ times shorter than typical nonlinear crystals, for relatively low irradiance values.

Solar Cell Temperature Dependent Efficiency And Very High Temperature Efficiency Limits, John Robert Wilcox

Open Access Dissertations

Clean renewable solar energy is and will continue to be a critically important source of electrical energy. Solar energy has the potential of meeting all of the world's energy needs, and has seen substantial growth in recent years. Solar cells can convert sun light directly into electrical energy, and much progress has been made in making them less expensive and more efficient. Solar cells are often characterized and modeled at 25 °C, which is significantly lower than their peak operating temperature. In some thermal concentrating systems, solar cells operate above 300 °C. Since increasing the temperature drastically affects the terminal …

New Covariance-Based Feature Extraction Methods For Classification And Prediction Of High-Dimensional Data, Mopelola Adediwura Sofolahan

Open Access Dissertations

When analyzing high dimensional data sets, it is often necessary to implement feature extraction methods in order to capture relevant discriminating information useful for the purposes of classification and prediction. The relevant information can typically be represented in lower-dimensional feature spaces, and a widely used approach for this is the principal component analysis (PCA) method. PCA efficiently compresses information into lower dimensions; however, studies indicate that it is not optimal for feature extraction especially when dealing with classification problems. Furthermore, for high-dimensional data having limited observations, as is typically the case with remote sensing data and nonstationary data such as …

Photovoltaic Tracker Optimization With Unique Fault Detection And Enhanced Combiner System, Caitlin Nicole Conway

Electrical & Computer Engineering Theses & Dissertations

Renewable energy resources are rapidly becoming extremely important as the world's energy consumption continues to rise. The most popular of these resources is solar energy and more specifically photovoltaic energy. Currently, solar modules on the market are still not highly efficient. In order to increase the productivity of solar energy systems, larger fixed-panel photovoltaic systems or tracking photovoltaic systems are utilized. The major disadvantage of larger photovoltaic systems is the increased space requirements. Therefore, tracking photovoltaic systems are the best alternative to achieve higher solar energy yields.

To date, the only method of monitoring tracking photovoltaic systems is with the …

Control System Of An Atomic Layer Deposition (Ald) Machine, Nitin Vishnu Hegde

Electrical & Computer Engineering Theses & Dissertations

Atomic Layer Deposition is one of the most efficient deposition processes for obtaining ultrathin films. The deposition by this process happens one atomic layer at a time. ALD is known for its precision and ability to develop quality films with great thickness control. ALD machines simultaneously control DC and AC currents, low pressure operations, temperature control and heating (up to 500'C), precision flow control, precision timing intervals for deposition (milli-second intervals) and constantly monitor temperature. Such a high control comes at a high price. Furthermore, at the university level, the capacity to modify or enhance a machine is critical but …

Physiologically-Motivated Feature Extraction Methods For Speaker Recognition, Jianglin Wang

Dissertations (1934 -)

Speaker recognition has received a great deal of attention from the speech community, and significant gains in robustness and accuracy have been obtained over the past decade. However, the features used for identification are still primarily representations of overall spectral characteristics, and thus the models are primarily phonetic in nature, differentiating speakers based on overall pronunciation patterns. This creates difficulties in terms of the amount of enrollment data and complexity of the models required to cover the phonetic space, especially in tasks such as identification where enrollment and testing data may not have similar phonetic coverage. This dissertation introduces new …

Theoretical Analysis Of Laterally Vibrating Hammerhead Microcantilever Sensors In A Viscous Liquid, Jinjin Zhang

Dissertations (1934 -)

Dynamically driven prismatic microcantilevers excited in the in-plane flexural mode have been investigated and used in liquid-phase sensing applications. However, the performance is restricted due to their limited surface sensing area and higher stiffness in shorter and wider prismatic microcantilevers. To increase the surface sensing area, and further improve sensing characteristics, it has been proposed to investigate symmetric hammerhead microcantilevers vibrating laterally in viscous liquid media. In this work, a theoretical model is proposed and the characteristics of the microcantilevers with symmetric shaped hammerheads (isosceles trapezoid, semi-circle, uniform rectangle and composite rectangle) are investigated. In the analysis, the stem of …

A Novel Design Optimization Of A Fault-Tolerant Ac Permanent Magnet Machine-Drive System, Peng Zhang

Dissertations (1934 -)

In this dissertation, fault-tolerant capabilities of permanent magnet (PM) machines were investigated. The 12-slot 10-pole PM machines with V-type and spoke-type PM layouts were selected as candidate topologies for fault-tolerant PM machine design optimization problems. The combination of 12-slot and 10-pole configuration for PM machines requires a fractional-slot concentrated winding (FSCW) layout, which can lead to especially significant PM losses in such machines. Thus, a hybrid method to compute the PM losses was investigated, which combines computationally efficient finite-element analysis (CE-FEA) with a new analytical formulation for PM eddy-current loss computation in sine-wave current regulated synchronous PM machines. These algorithms …

Comparison Of Three Space Vector Pwm Methods For A Three-Level Inverter With A Permanent Magnet Machine Load, Alia Rebecca Strandt

Master's Theses (2009 -)

Much work exists on multilevel space vector pulse width modulation (PWM) to drive induction machines, in which the rotor currents are induced by stator rotating field effects. However, there are few investigations that analyze these modulation methods applied to permanent magnet (PM) and wound-field synchronous machines, in which the rotor induces a back emf in the stator. In this thesis, three different three-level space vector PWM switching sequences are applied to a three-level neutral-point-clamped (NP) inverter driving an internal permanent magnet (IPM) machine load. The inherent qualities of each of the switching sequences when under the influence of a forcing …

Non-Negative Matrix Factorization Based Algorithms To Cluster Frequency Basis Functions For Monaural Sound Source Separation., Rajesh Jaiswal

Doctoral

Monophonic sound source separation (SSS) refers to a process that separates out audio signals produced from the individual sound sources in a given acoustic mixture, when the mixture signal is recorded using one microphone or is directly recorded onto one reproduction channel. Many audio applications such as pitch modification and automatic music transcription would benefit from the availability of segregated sound sources from the mixture of audio signals for further processing. Recently, Non-negative matrix factorization (NMF) has found application in monaural audio source separation due to its ability to factorize audio spectrograms into additive part-based basis functions, where the parts …

Understanding Vehicular Traffic Behavior From Video: A Survey Of Unsupervised Approaches, Brendan Tran Morris, Mohan Manubhai Trivedi

Electrical & Computer Engineering Faculty Research

Recent emerging trends for automatic behavior analysis and understanding from infrastructure video are reviewed. Research has shifted from high-resolution estimation of vehicle state and instead, pushed machine learning approaches to extract meaningful patterns in aggregates in an unsupervised fashion. These patterns represent priors on observable motion, which can be utilized to describe a scene, answer behavior questions such as where is a vehicle going, how many vehicles are performing the same action, and to detect an abnormal event. The review focuses on two main methods for scene description, trajectory clustering and topic modeling. Example applications that utilize the behavioral modeling …

Footwear Antennas For Body Area Telemetry, Domenico Gaetano, Patrick Mcevoy, Max Ammann, Jacinta Browne, Louise Keating, Frances Horgan

Articles

Antennas designed to link footwear sensors within body centric networks are introduced with two small UWB antennas, one directional and another quasi-omnidirectional. The radiating characteristics are evaluated for three positions on a sample sports shoe using a detailed simulation model and measurements with a homogenous foot phantom. Antenna performance is assessed for resilience to close proximity loading by the footwear materials and the phantom foot.

Small-Scale Wind Turbines: An Appraisal, Tony Kealy

Conference Papers

This research seeks to evaluate the economic benefits to be gained by installing a small-scale wind turbine for a customer with a three-phase electrical supply requirement. The evidence for the claims made in this paper is obtained by using actual data obtained from the installed equipment over a three year period. The objective is to accurately appraise the financial investment using real data. There appears to be limited studies conducted into this type of research, possibly because the renewable energy sector is in the infancy stage in the host country, Ireland. There are some wind energy installations with financial appraisal …

Nonlinear Dynamics Of Bragg-Domain Acousto-Optic Hybrid Feedback For First-Order Scattering Of Profiled Optical Beams, Monish Ranjan Chatterjee, Fares S. Almehmadi

Electrical and Computer Engineering Faculty Publications

A series of recent studies involving hybrid acousto-optic (AO) scattering in the Bragg domain under first-order feedback have shown the ability of the AO feedback system to encrypt, transmit and decrypt RF information applied via the sound driver. The basic premise of this operation is founded on the chaotic nature of the hybrid Bragg cell under feedback.