Digital Commons Network^™

Magnetic Equivalent Circuit Modeling Of Induction Motors, S. D. Sudhoff, Brian T. Kuhn, Keith Corzine, Brian T. Branecky

Electrical and Computer Engineering Faculty Research & Creative Works

Finite element models are invaluable for determining expected machine performance. However, finite element analysis can be computationally intense; particularly if a large numbers of studies or high bandwidth studies are required. One method to avoid this difficulty is to extract machine parameters from the finite element model and use the parameters in lumped parameter models. While often useful, such an approach does not represent space harmonics or asymmetries in the motor. A methodology for constructing a state-variable model, based on a magnetic equivalent circuit of the motor is described herein. In addition, the parameters for this model are based solely …

A First Course In Power: Can A Single Course Serve All Students?, Mariesa Crow, Badrul H. Chowdhury, Keith Corzine, Mehdi Ferdowsi

Electrical and Computer Engineering Faculty Research & Creative Works

This paper is part of a panel entitled "Modernizing the First Course in Power Systems." In this paper the authors discuss the first power course requirement at the University of Missouri-Rolla. Undergraduate students are required to take a power course, but they may select between a power systems course or a electromechanical conversion course.

Control Methods In Dc-Dc Power Conversion -- A Comparative Study, Kai-Tak Wan, Jingsheng Liao, Mehdi Ferdowsi

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Several control techniques for dc-dc power conversion and regulation have been studied in this paper. Analog approaches have briefly been described since the focus is the newly developed digital techniques. Principles of operation, advantages, and disadvantages of each control method have been described. Simulation results have been used to compare the performance and accuracy of digital control techniques.

A Novel Impedance Measurement Technique For Power Electronic Systems, Peng Xiao, Ganesh K. Venayagamoorthy, Keith Corzine

Electrical and Computer Engineering Faculty Research & Creative Works

When designing and building power systems that contain power electronic switching sources and loads, system integrators must consider the frequency-dependent impedance characteristics at an interface to ensure system stability. Stability criteria have been developed in terms of source and load impedance for both dc and ac systems and it is often necessary to measure system impedance through experiments. Traditional injection-based impedance measurement techniques require multiple online tests which lead to many disadvantages. The impedance identification method proposed in this paper greatly reduces online test time by modeling the system with recurrent neural networks. The recurrent networks are trained with measured …

Adaptive Control Strategy For Active Power Sharing In Hybrid Fuel Cell/Battery Power Sources, Zhenhua Jiang, Lijun Gao, Roger A. Dougal

Faculty Publications

Hybrid systems composed of fuel cells and batteries combine the high energy density of fuel cells with the high power density of batteries. A dc/dc power converter is placed between the fuel cell and the battery to balance the power flow between them and greatly increase the peak output power of the hybrid. This paper presents an adaptive control strategy for active power sharing in the hybrid power source. This control strategy can adjust the output current setpoint of the fuel cell according to the state-of-charge (or voltage) of the battery, and is applicable in two topologies of active fuel …

A Small-Scale 3d Imaging Platform For Algorithm Performance Evaluation, Steven A. James

Theses and Dissertations

In recent years, world events have expedited the need for the design and application of rapidly deployable airborne surveillance systems in urban environments. Fast and effective use of the surveillance images requires accurate modeling of the terrain being surveyed. The process of accurately modeling buildings, landmarks, or other items of interest on the surface of the earth, within a short lead time, has proven to be a challenging task. One approach of high importance for countering this challenge and accurately reconstructing 3D objects is through the employment of airborne 3D image acquisition platforms. While developments in this arena have significantly …

Controller Design For Accurate Antenna Pointing Onboard A Spacecraft, Victor M. Barba

Theses and Dissertations

Controller design for a spacecraft mounted flexible antenna is considered. The antenna plant model has a certain degree of uncertainty. Additionally, disturbances from the host spacecraft are transmitted to the antenna and need to be attenuated. The design concept explored herein entails feedforward control to slew the antenna. Feedback control is then used to compensate for plant uncertainty and to reject the disturbance signals. A tight control loop is designed to meet performance specifications while minimizing the control gains. Simulations are conducted to show that the integration of feedforward control action and feedback compensation produces better responses than the implementation …

An Experimental Investigation Of Parallel Multimedia Streams Over Ieee 802.11e Wlan Networks Using Txop, Nicola Cranley, Tanmoy Debnath, Mark Davis

Conference papers

In this paper we perform an experimental investigation of the IEEE 802.11 TXOP facility to enhance the transmission of parallel multimedia streaming sessions through efficient bandwidth reservation and explicitly consider both the audio and video streams. The delay constraints associated with the audio and video streams that comprise a multimedia session pose the greatest challenge since real-time multimedia is particularly sensitive to delay as the packets require a strict bounded end-to-end delay. We show how the TXOPlimit parameter can be efficiently dimensioned to reduce the tranmission delay for the video frames. Due to tis frame-based nature, video applications are considered …

Differential Evolution Approach For Reactive Power Optimization Of Nigerian Grid System, G. A. Bakare, G. Krost, Ganesh K. Venayagamoorthy, U. O. Aliyu

Electrical and Computer Engineering Faculty Research & Creative Works

The goal of reactive power dispatch is to minimize the system losses and improve the system voltage profiles at all times. This is achieved by adjusting various generating units' excitation systems continuously, discrete tap positions of on-load tap changers of transformers as well as switching of correct doses of inductors or capacitors. This is a mixed integer non-linear optimization problem. In this paper, the differential evolution (DE), a novel evolutionary computation technique which was originally designed for continuous problems is applied to solve this problem. DE appears to ally qualities of established computational intelligence (CI) techniques with a more striking …

Digital Ripple Correlation Control For Photovoltaic Applications, Jonathan W. Kimball, Philip T. Krein

Electrical and Computer Engineering Faculty Research & Creative Works

Ripple correlation control (RCC) is a fast, robust online optimization technique. RCC is particularly suited for switching power converters, where the inherent ripple provides information about the system operating point. The present work examines a digital formulation that has reduced power consumption and greater robustness. A maximum power point tracker for a photovoltaic panel demonstrates greater than 99% tracking accuracy and fast convergence.

Reliability Studies Of Tin/Hf-Silicate Based Gate Stacks, Naser Ahmed Chowdhury

Dissertations

Hafnium-silicate based oxides are among the leading candidates to be included into the first generation of high-Κ gate stacks in nano-scale CMOS technology because of their distinct advantages as far as thermal stability, leakage characteristics, threshold stability and low mobility degradation are concerned. Their reliability, which is limited by trapping at pre-existing and stress induced defects, remains to be a major concern.

Energy levels of electrically active ionic defects within the thick high-Κ have been experimentally observed in the context of MOS band diagram for the first time in Hf-silicate gate stacks from low temperature and leakage measurements. Excellent match …

Design And Performance Of Cdma Codes For Multiuser Communications, Radharani Poluri

Dissertations

Walsh and Gold sequences are fixed power codes and are widely used in multiuser CDMA communications. Their popularity is due to the ease of implementation. Availability of these code sets is limited because of their generating kernels. Emerging radio applications like sensor networks or multiple service types in mobile and peer-to-peer communications networks might benefit from flexibilities in code lengths and possible allocation methodologies provided by large set of code libraries.

Walsh codes are linear phase and zero mean with unique number of zero crossings for each sequence within the set. DC sequence is part of the Walsh code set. …

Titanium Nitride As An Electrode Material For High Charge Density Applications, Mustafa Khan Patan

Theses

Present day neural prostheses require electrodes with high current densities. Traditional electrodes are not capable of delivering such high current densities. Titanium nitride as an electrode material and other techniques like reactive ion etching, platinization of titanium were studied in this thesis towards improving charge density of electrodes.

Titanium nitride (TiN) was sputtered in a custom designed pattern of electrodes with silicon as substrate, at a deposition rate of 2 A /sec. Atomic Force Microscopy (AFM) analysis of TiN film showed a smooth surface for a film thickness of 1 μm. X-Ray Diffraction (XRD) analysis of the film showed the …

On-Chip Surface-Enhanced Raman Scattering Detection Using Integrated Liquid-Core Waveguides, Aaron R. Hawkins, Evan J. Lunt, Phillip Measor, Leo Seballos, Dongliang Yin, Jin Z. Zhang, Holger Schmidt

Faculty Publications

The authors demonstrate surface-enhanced Raman scattering (SERS) detection on an optofluidic chip. Interconnected solid- and liquid-core antiresonant reflecting optical waveguides (ARROWs) form a planar beam geometry that allows for high mode intensities along microfluidic channels containing molecules optimized for SERS. The excitation power and concentration dependence of SERS from rhodamine 6G (R6G) molecules adsorbed to silver nanoparticles were systematically studied. The data can be described by a model that takes into account the microphotonic structure. Detection sensitivity to a minimum concentration of 30 nM is found, demonstrating the suitability of ARROW-based optofluidic chips for high sensitivity detection with molecular specificity

Broadband Ellipsometer Or Polarimeter System Including At Least One Multiple Element Lens, Martin M. Liphardt, Blaine D. Johs, Jeffrey S. Hale, Craig M. Herzinger, Steven E. Green, Ping He, John A. Woollam

Department of Electrical and Computer Engineering: Faculty Publications

Quasi-achromatic multi-element lens(es) which are precisely mounted with respect to one another in a tubular mounting fixture, and the application thereof in focusing, (and optionally re-colliminating), a spectroscopic electromagnetic beam into a very small, chromatically relatively undispersed, area spot on a material system.

Software Development For Mechatronics Systems: Simulation Of Multiple Uav Navigation And Device Driver Interface For The Q4 Data Acquisition Card, Ninad Pradhan

All Theses

Mechatronics systems are often a close interleaving of different aspects of hardware, software, control and mechanical design. Two such aspects are delved into in greater detail for this thesis, both related to software development.
Simulations are used to know the practical conditions under which a control design is effective. The system simulated in this case was a multiple vehicle system, where the vehicles navigated from source to a destination configuration avoiding two different kinds of obstacles.
Post simulation, a system is implemented using hardware and tested using an experimental setup. Data Acquisition Boards such as the Quanser Q4 are used …

System For And Method Of Investigating The Exact Same Point On A Sample Substrate With Multiple Wavelengths, Galen L. Pfeiffer, Martin M. Liphardt, Blaine D. Johs, Craig M. Herzinger, Christopher A. Goeden, Ping He, John A. Woollam, James D. Welch

Department of Electrical and Computer Engineering: Faculty Publications

Disclosed are system for and method of analyzing a sample at substantially the exact same small spot point on a sample with a plurality of wavelengths.

An Efficient Analysis Of Vertical Dipole Antennas Above A Lossy Half-Space , Yongfeng Huang

All Theses

The electromagnetic modeling of radiation by vertical dipole antennas above a lossy half-space has become an important subject due to many applications where these dipoles are involved. The modeling often encounters Sommerfeld-type integrals that are normally highly oscillatory with poor convergence. Recently, an efficient computation of the electric field radiated by an infinitesimal electric dipole above a lossy half-space has been reported, in which the Sommerfeld-type integrals are reduced to rapidly-converging integrals. Taking advantage of such efficiently-calculated electric field and using it as the Green's function, in this thesis, an electric field integral equation (EFIE) is formulated for the analysis …

System For And Method Of Investigating The Exact Same Point On A Sample Substrate With Multiple Wavelengths, Galen L. Pfeiffer, Martin M. Liphardt, Blaine D. Johs, Craig M. Herzinger, Christopher A. Goeden, Ping He, John A. Woollam, James D. Welch

Department of Electrical and Computer Engineering: Faculty Publications

Disclosed are system for and method of analyzing a sample at Substantially the exact same Small spot point on a sample with a plurality of wavelengths.

Improving Dc Power Supply Efficiency With Neural Network Controller, Weiming Li, Xiao-Hua Yu

Electrical Engineering

DC-DC converters can be found in almost every power electronics device. To improve the efficiency and controller response of a DC-DC converter to dynamical ~stem changes, neural network has been chosen as an alternative to classic methods. However, no prior work has been done in the neural network approach for control of a PSFB (phase-Shifted Full-Bridge) converter yet. In this research, a multi-layer feedforward neural network controller is proposed. The neural network based controller has the advantage of adaptive learning ability, and can work under the situation when the input voltage and load current fluctuate. Levenberg-Marquardt backpropagation training algorithm is …

Design Of A Low-Power Automatic Wireless Multi-Logger Networking Device, Kelly S. Lewis

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Virtually every industry and discipline (e.g., mining, pharmaceutical, construction, agriculture, reclamation, etc.) is finding applications for wireless data acquisition for monitoring and managing processes and resources. Two sectors, namely agriculture and environmental research, are seeking ways to obtain distributed soil and plant measurements over larger areas like a watershed or large fields rather than a single site of intensive instrumentation (i.e., a weather station). Wireless sensor networks and remote sensing have been explored as a means to satisfy this need. Commercial products are readily available that have remote wireless options to support distributed senor networking. However, these systems have been …

A Formal Approach To Specifying And Verifying Spacecraft Behavior, Allan I.S. Mcinnes

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Process algebra can provide spacecraft designers with a mathematical formalism for specifying, understanding, analyzing, and verifying spacecraft system behavior. Although it is standard practice to mathematically model and analyze the subsystems of a spacecraft to ensure that they will function correctly when built, the system-level behavior of the spacecraft is generally understood in much less rigorous terms. This leaves the spacecraft system vulnerable to design errors which may not become apparent until the integration and test phase, when design changes are most expensive. In this dissertation, we develop a formal approach to engineering spacecraft behavior, based on mathematical models of …

The History And Dynamics Of The Plasma Impedance Probe, Wayne G. Sanderson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

For over 40 years Utah State University / Space Dynamics Laboratory and their predecessors have built instruments to measure electron density in the ionosphere. These instruments have incrementally improved as new measuring techniques have developed and new technologies have been introduced. This thesis introduces the properties and measurement of electron density in the ionosphere. It maps the instrument advancements from the early radio frequency probes of the 1960's to the present Plasma Impedance Probe (PIP), with emphasis on the introduction of the phase lock looped Plasma Frequency Probe (PFP) and the rediscovery of the Swept Impedance Probe (SIP). The current …

Tropospheric Spectrum Estimations Comparing Maximum Likelihood With Expectation Maximization Solutions And Fast Fourier Transforms, Stanley James Wellard

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The FIRST program (Far Infrared Spectroscopy in the Troposphere) was created as an Instrument Incubator Program (IIP) by NASA Langley to demonstrate improved technology readiness levels (TRLs) for two technologies needed in the design of new imaging Fourier transform spectrometers (IFTS). The IIP IFTS was developed at the Space Dynamics Laboratory and flown to an altitude of 103,000 feet on an instrumented NASA balloon payload. The sensor collected approximately 15,000 interferograms during its 6-hour flight.

Fourier transforms (FFT) produced acceptable results except for noise equivalent temperature differences (NETD) that were five times higher than goal and inconclusive transforms at seven …

H-Infinity Output Feedback Control: Application To Unmanned Aerial Vehicle, Jyotirmay Gadewadikar

Electrical Engineering Dissertations - Archive

This dissertation presents new necessary and sufficient conditions for static output-feedback control of linear time-invariant systems using the H-Infinity approach. Simplified conditions are derived which only require the solution of two coupled matrix design equations. It is shown that the static output-feedback H-Infinity solution does not generally yield a well-defined saddle point for the zero sum differential game; conditions are given under which it does. This work presents a simplified parameterization of all H-Infinity static state-feedback controllers in terms of a single algebraic Riccati equation and a free parameter matrix. As a special case, necessary and sufficient conditions for the …

Distributed Cooperative Framework And Algorithms For Wireless Network Performance Optimization, Emily Hong Qi

Dissertations and Theses

In Wireless Local Access Networks (WLANs), the Medium Access Control (MAC) protocol is the primary element that determines the efficiency of sharing the limited communication bandwidth of the wireless channel. IEEE 802.11 MAC uses the contention-based Distributed Coordination Function (DCF) as a fundamental medium access mechanism. However, the dynamic nature of the wireless environment creates mobility challenges of maintaining maximum channel capacity, of obtaining optimal throughput and latency, and of retaining good security in a distributed wireless network.

This dissertation first introduces a set of parameters to characterize the medium status and radio environment, and a mechanism for mobile devices …

Experimental Characterization Of The Outdoor Mimo Wireless Channel Temporal Variation, Michael A. Jensen, Karl F. Warnick, Jon W. Wallace, Ajay Gummalla, Harry B. Lee

Faculty Publications

Time-variant multiple-input multiple-output (MIMO) channels are measured in an outdoor campus environment at 2.45 GHz with directional patch arrays and omnidirectional monopole arrays. A number of useful metrics are proposed for quantifying time variation in MIMO channels: eigenvalue level crossing rate, eigenvector angular deviation, and capacity loss for delayed transmit and receive channel state information (CSI). Measurements in four different environments confirm the strong correlation between angular spread of multipath and MIMO channel time variability. The rate of time variation is also strongly influenced by the type of array, indicating that directional elements may be advantageous for highly mobile environments. …

The Relationship Between Antenna Loss And Superdirectivity In Mimo Systems, Michael A. Jensen, Nicolas W. Bikhazi

Faculty Publications

Multiple-input multiple-output (MIMO) communication systems can theoretically use array superdirectivity to optimally exploit the propagation channel. This superdirectivity leads to very large capacity bounds, particularly when the antennas are closely spaced. However, because superdirective behavior is difficult to achieve in practice, new capacity bounds have been formulated for the case where the level of array superdirectivity is constrained. Existing capacity analyses limit the superdirectivity in a suboptimal way. In this paper, the impact of superdirectivity in the capacity solution is limited by introducing finite ohmic loss in the transmit and receive antenna elements. Computational results reveal that even a small …

An Overview Of Mav Research At Brigham Young University, Timothy W. Mclain, Randal W. Beard, D. Blake Barber, Nathan B. Knoebel

Faculty Publications

This paper summarizes research efforts at Brigham Young University related to the control of miniature aerial vehicles (MAVs). Recent results in the areas of vector field path following, precision landing and target prosecution, target localization, obstacle detection and avoidance, tailsitter aircraft control, and cooperative control are presented.

Soar Checkers - An Intelligent Checkers Playing Agent In Soar, Jithu Menon

All Theses

The classic board game of checkers is ideally suited for research in AI game-playing programs or agents. The objective behind Soar Checkers is to investigate if it is possible to create an agent-based game playing system that would beat novices with ease and at least challenge advanced novice to intermediate-level players by designing a rules-based expert system whose knowledge base consists of nothing more than the rules of checkers, and a set of guidelines for game-play based on good strategy. Soar was chosen as the platform for building this agent because it came built-in with features that facilitate creating rules-based …