Electrical and Computer Engineering Commons^™

Neural Networks Skin Tumor Diagnostic System, Zhao Zhang, William V. Stoecker, Randy Hays Moss

Electrical and Computer Engineering Faculty Research & Creative Works

In this study, a malignant melanoma diagnostic system is designed using a straightforward neural network with the back-propagation learning algorithm. Eleven features are automatically extracted from skin tumor images. The correct diagnostic rate of this system is better than the average rate of 16 dermatologists who based their diagnosis with only the slide images.

Neuro Emission Controller For Minimizing Cyclic Dispersion In Spark Ignition Engines, Pingan He, Jagannathan Sarangapani

Electrical and Computer Engineering Faculty Research & Creative Works

A novel neural network (NN) controller is developed to control spark ignition (SI) engines at extreme lean conditions. The purpose of neurocontroller is to reduce the cyclic dispersion at lean operation even when the engine dynamics are unknown. The stability analysis of the closed-loop control system is given and the boundedness of all signals is ensured. Results demonstrate that the cyclic dispersion is reduced significantly using the proposed controller. The neuro controller can also be extended to minimize engine emissions with high EGR levels, where similar complex cyclic dynamics are observed. Further, the proposed approach can be applied to control …

Over-Distention Operation Of Cascaded Multilevel Inverters, X. Kou, Keith Corzine, M. W. Wielebski

Electrical and Computer Engineering Faculty Research & Creative Works

Established research has shown that cascaded multilevel inverters can provide more voltage vectors per number of active semiconductors compared to typical multilevel converters. This feature is significant for increasing the drive performance as well as reducing the drive complexity and losses. When two inverters are cascaded, the maximum number of effective levels (or maximal distention operation) is the product of the number of levels of the individual inverters. It is possible to operate the cascaded inverter beyond maximum distention. The over-distention operation is desirable since it effectively increases the number of voltage levels in spite of some missing switching levels. …

Probabilistic Neural Networks For Multi-Class Tissue Discrimination With Gene Expression Data, Rui Xu, Donald C. Wunsch

Electrical and Computer Engineering Faculty Research & Creative Works

With the emergence and rapid advancement of DNA microarray technologies, construction of gene expression profiles for different cancer types has already become a promising means for cancer diagnosis and treatment. Most previous research has focused on binary classification. Here, we use a probabilistic neural network (PNN) for multi-classification of cancer data. The experimental results demonstrate the effectiveness of the PNN in addressing gene expression data.

Fatigue Testing Of A Composite Propeller Blade Using Fiber-Optic Strain Sensors, Steve Eugene Watkins, V. E. Zetterlind Iii, M. W. Spoltman

Electrical and Computer Engineering Faculty Research & Creative Works

The performance of surface-mounted extrinsic Fabry-Perot interferometric (EFPI) sensors during a seventeen-million-cycle, high-strain fatigue test is reported. Fiber-optic strain measurements did not degrade during the test. The sensors were applied to a composite propeller blade subject to a constant axial load and a cyclic bending load. Strain measurements were taken at four blade locations using two types of EFPI sensors and co-located electrical resistance strain gages. Static and dynamic strain measurements were taken daily during the 65 days of this standard propeller-blade test. All fiber-optic sensors survived the fatigue test while most of the resistive gages failed. The suitability of …

Fdtd Data Extrapolation Using Multilayer Perceptron (Mlp), H. Goksu, David Pommerenke, Donald C. Wunsch

Electrical and Computer Engineering Faculty Research & Creative Works

This work compares MLP with the matrix pencil method, a linear eigenanalysis-based extrapolator, in terms of their effectiveness in finite difference time domain (FDTD) data extrapolation. Matrix pencil method considers the signal as superposed complex exponentials while MLP considers each time step to be a nonlinear function of previous time steps.

Scene-Based Nonuniformity Correction For Focal Plane Arrays By The Method Of The Inverse Covariance Form, Sergio N. Torres, Jorge E. Pezoa, Majeed M. Hayat

Electrical and Computer Engineering Faculty Research and Publications

What is to our knowledge a new scene-based algorithm for nonuniformity correction in infrared focal-plane array sensors has been developed. The technique is based on the inverse covariance form of the Kalman filter (KF), which has been reported previously and used in estimating the gain and bias of each detector in the array from scene data. The gain and the bias of each detector in the focal-plane array are assumed constant within a given sequence of frames, corresponding to a certain time and operational conditions, but they are allowed to randomly drift from one sequence to another following a discrete-time …

Antenna-Coupled Infrared Focal Plane Array, Francisco Javier Gonzalez

Retrospective Theses and Dissertations

In this dissertation a new type of infrared focal plan array (IR FPA) was investigated, consisting of antenna-coupled microbolometer fabricated using electron-beam lithography. Four different antenna designs were experimentally demonstrated at 10-micron wavelength: dipole, bowtie, square-spiral, and log-periodic. The main differences between these antenna types were their bandwidth, collection area, angular reception pattern, and polarization. To provide pixel collection areas commensurate with typical IR FPA requirements, two configurations were investigated: a two-dimensional serpentine interconnection of individual IR antennas, and a Fresnel-zone-plate (FZP) coupled to a single-element antenna. Optimum spacing conditions for the two-dimensional interconnect were developed. Increased sensitivity was demonstrated …

A Numerical Investigation Of Interior Resonances In The Hybrid Fem/Mom Method, Yun Ji, Hao Wang, Todd H. Hubing

Electrical and Computer Engineering Faculty Research & Creative Works

The interior resonance problem that can occur when using a hybrid finite-element method/method of moments (FEM/MoM) method to model electromagnetic scattering problems is investigated. Calculations of the bistatic radar cross section of a coated dielectric sphere are presented using different formulations, solution approaches, and solvers. The solutions using the electric-field integral equation have significant errors near an interior resonance frequency. When the combined-field integral equation is employed, satisfactory solutions can be obtained that do not depend on the particular solution approach or solver.

Comparison Of Particle Swarm Optimization And Backpropagation As Training Algorithms For Neural Networks, Ganesh K. Venayagamoorthy, Venu Gopal Gudise

Electrical and Computer Engineering Faculty Research & Creative Works

Particle swarm optimization (PSO) motivated by the social behavior of organisms, is a step up to existing evolutionary algorithms for optimization of continuous nonlinear functions. Backpropagation (BP) is generally used for neural network training. Choosing a proper algorithm for training a neural network is very important. In this paper, a comparative study is made on the computational requirements of the PSO and BP as training algorithms for neural networks. Results are presented for a feedforward neural network learning a nonlinear function and these results show that the feedforward neural network weights converge faster with the PSO than with the BP …

On Implementing Dynamically Reconfigurable Architectures, Hatem Mahmoud El-Sayed El-Boghdadi

LSU Doctoral Dissertations

Dynamically reconfigurable architectures have the ability to change their structure at each step of a computation. This dissertation studies various aspects of implementing dynamic reconfiguration, ranging from hardware building blocks and low-level architectures to modeling issues and high-level algorithm design. First we derive conditions under which classes of communication sets can be optimally scheduled on the circuit-switched tree (CST). Then we present a method to configure the CST to perform in constant time all communications scheduled for a step. This results in a constant time implementation of a step of a segmentable bus, a fundamental dynamically reconfigurable structure. We introduce …

Design For Signal Integrity In High Frequency, High Density Circuit Boards, Juan Manuel Talavera Martinez

Theses

The electronics market is continually seeking fast and small high performance products. The clock frequency in computer systems is often above 2GHz and new generations of laptops have considerably reduced in size. These features make printed circuit board (PCB) design more difficult than in the past.

This thesis is an investigation of the current design of high speed PCB. The complexity of this type of circuit makes the designer needs an extensive knowledge of the techniques used to generate a reliable signalling, in other words, signal integrity. To achieve this objective, the design community has to overcome several problem related …

Automated Distribution And Management Of Software And Hardware Configurations For Heterogeneous Wireless Devices, Grainne Foley

Theses

The continuing evolution of wireless networks and services has increased the complexity and diversity of wireless networks and devices, placing significant emphasis on the need for flexible device configuration management. Widely varying wireless technologies currently operate independently worldwide, making global wireless network access for the mobile user confusing and unwieldy. New technologies, network access methodologies and improved services further obscure the evolving environment. The focus of effort for this thesis is the development of a system to automate the distribution and management of software and hardware configurations that enable different levels of wireless device reconfiguration. The scope of investigation will …

Dynamically Biased Radio Frequency Power Amplifier, Tom Twomey

Theses

With the current trend in mobile communications towards more complex modulation schemes to enhance spectral efficiency, the design of RF power amplifiers is the subject of considerable interest and research. The newer more spectrally efficient modulation schemes require a much higher level of linearity due to the non-constant level of their signal envelope. A variable envelope signal would in non-linear amplifiers lead to unacceptable levels of distortion. Linear amplifiers solve this problem at the cost of significant loss of efficiency. With the evolution towards more spectrally efficient modulation schemes, the trade off between linearity and power efficiency has become more …

Performance Evaluation Of Sip Based Services In Umts, Maria Isabel Pous Fenollar

Theses

With ever increasing penetration of IP technologies and the tremendous growth in wireless data traffic, the wireless industry is evolving the mobile core networks towards IP technology. The 3rd Generation Partnership Project (3GPP) is specifying an IP Multimedia Core Network Sub-System (IMS) in UMTS Release 5 and Release 6, which is adjunct to the UMTS GPRS core network. This IP-based network will allow mobile operators to provide commonly used Internet applications to wireless user. The UMTS IMS uses the Internet Engineering Task Force (IETF) defined text based Session Initiation Protocol (SIP), to control a wide range of anticipated IP-based services …

Novel High Frequency Silicon Carbide Static Induction Transistor-Based Test-Bed For The Acquisition Of Sic Power Device Reverse Recovery Characteristics, Kevin M. Speer, Ty R. Mcnutt, Alexander B. Lostetter, H. Alan Mantooth, Kraig J. Olejniczak

Journal of the Arkansas Academy of Science

A test system is presented that utilizes a high-frequency Silicon Carbide (SiC) Static Induction Transistor (SIT) in place of the traditional MOSFET to test reverse recovery characteristics for the new class of SiC power diodes. An easily implementable drive circuit is presented that can drive the high-frequency SIT. The SiC SIT is also compared to a commonly used Si MOSFET in the test circuit application.

Parameter Extraction Software For Compact Diode Model, Maruf Hossain, Edgar Cilio, Ty R. Mcnutt, Alexander B. Lostetter, H. Alan Mantooth

Journal of the Arkansas Academy of Science

No abstract provided.

Testing And Modeling Electrical Characteristics Of Novel Silicon Carbide (Sic) Static Induction Transistors (Sits), Avinash S. Kashyap, Sharmila D. Mangan Lal, Ty R. Mcnutt, Alexander B. Lostetter, H. Alan Mantooth

Journal of the Arkansas Academy of Science

No abstract provided.

Simple Plane Wave Implementation For Photonic Crystal Calculations, Shangping Guo, Sacharia Albin

Electrical & Computer Engineering Faculty Publications

A simple implementation of plane wave method is presented for modeling photonic crystals with arbitrary shaped ‘atoms’. The Fourier transform for a single ‘atom’ is first calculated either by analytical Fourier transform or numerical FFT, then the shift property is used to obtain the Fourier transform for any arbitrary supercell consisting of a finite number of ‘atoms’. To ensure accurate results, generally, two iterating processes including the plane wave iteration and grid resolution iteration must converge. Analysis shows that using analytical Fourier transform when available can improve accuracy and avoid the grid resolution iteration. It converges to the accurate results …

Motion Planning Using Potential Fields, Randal W. Beard, Timothy W. Mclain

Faculty Publications

The objective of these notes is to describe a reactive approach to motion planning for mobile robots. In a reactive approach, trajectories are not planned explicitly. Rather, robot interactions are defined explicitly and the robot motion is said to "emerge." The drawback of reactive methods is that it is sometimes difficult to get the robot to do exactly what you want. The reactive approach that will be described in these notes is called the "virtual fields" method and is commonly used in robotics.

Plasma Interaction With Microbes, M. Laroussi, D. A. Mendis, M. Rosenberg

Electrical & Computer Engineering Faculty Publications

The germicidal effects of a non-equilibrium atmospheric pressure plasma generated by a novel resistive barrier discharge on representatives of the two classes of bacteria (Gram-negative and Gram-positive) are discussed. The plasma exposure, while being lethal to both bacterial classes, also produced gross structural damage in the Gram-negative E. coli while none was observed in the more structurally robust Gram-positive Bacillus subtilis. An electrophysical process involving the role of the electrostatic tension on a charged body in a plasma is invoked to explain both observations. Since the efficacy of this electrophysical process depends not only on the tensile strength of …

Electron Bernstein Wave-X-O Mode Conversion And Electron Cyclotron Emission In Mast, Josef Preinhaelter, Pavol Pavlo, Vladimir Shevchenko, Martin Valovic, Linda L. Vahala, George Vahala

Electrical & Computer Engineering Faculty Publications

Electron cyclotron emission (ECE) from overdense plasmas can only occur due to electron Bernstein waves (EBW) mode converting near the upper hybrid region to an electromagnetic wave. Experimental data of ECE observations on MAST are studied and compared with EBW-X-O mode conversion modeling results.

Compact Supercell Method Based On Opposite Parity For Bragg Fibers, Wang Zhi, Ren Guobin, Lou Shuquin, Liang Weijun, Shangping Guo

Electrical & Computer Engineering Faculty Publications

The supercell- based orthonormal basis method is proposed to investigate the modal properties of the Bragg fibers. A square lattice is constructed by the whole Bragg fiber which is considered a supercell, and the periodical dielectric structure of the square lattice is decomposed using periodic functions (cosine). The modal electric field is expanded as the sum of the orthonormal set of Hermite-Gaussian basis functions based on the opposite parity of the transverse electric field. The propagation characteristics of Bragg fibers can be obtained after recasting the wave equation into an eigenvalue system. This method is implemented with very high efficiency …

Numerical Techniques For Excitation And Analysis Of Defect Modes In Photonic Crystals, Shangping Guo, Sacharia Albin

Electrical & Computer Engineering Faculty Publications

Two numerical techniques for analysis of defect modes in photonic crystals are presented. Based on the finite-difference time-domain method (FDTD), we use plane wave incidences and point sources for excitation and analysis. Using a total-field/scattered-field scheme, an ideal plane wave incident at different angles is implemented; defect modes are selectively excited and mode symmetries are probed. All modes can be excited by an incident plane wave along a non-symmetric direction of the crystal. Degenerate modes can also be differentiated using this method. A proper arrangement of point sources with positive and negative amplitudes in the cavity flexibly excites any chosen …

Transmission Property And Evanescent Wave Absorption Of Cladded Multimode Fiber Tapers, Shangping Guo, Sacharia Albin

Electrical & Computer Engineering Faculty Publications

Cladded multimode fiber optic tapers are proposed as chemical sensors using evanescent wave absorption. There is no need to strip the cladding; therefore, fabrication is easy and the taper is mechanically stronger than the taper without cladding. The transmission property and evanescent wave absorption are modeled using ray theory and wave theory, respectively. Effects of some parameters on the absorption sensitivity are analyzed numerically. Due to the presence of the cladding, the taper core is not in direct contact with the external medium, leading to some significant differences from the uncladded one, especially when the index of the external medium …

Distributed Sensor Network For Civil Infrastructure Health Monitoring, Jose Humberto Mata Hernandez

Masters Theses

"This thesis focuses on the development of a robust, low power consumption and cost effective wireless data acquisition, system to be used for civil infrastructure health monitoring. The complete solution that has been developed for this application integrates micro-electromechanical sensing elements (e.g. PVDF sensor); a wireless data acquisition system based on a Bluetooth-enabled radio, a microcontroller with analog to digital conversion capabilities, a power source including a solar cell array for long term operation, and a weatherproof enclosure for on-site installation. The complementary part of the solution is a weatherproof On-site Remote Access Point (ORAP) which collects, stores, and transmits …

Common- And Differential-Mode Signaling And Filtering, Zhe Li

Masters Theses

"Common-mode chokes are widely used as suppression filters against interference of common-mode noise in high-speed differential signaling. This thesis focuses on investigating the characteristics of common-mode chokes. Mixed-mode S-parameters are presented as a useful concept for explaining the modal operation of differential circuits.

Three methods for measuring common-mode and differentia-mode S-parameters of common-mode chokes are demonstrated. The three methods involve (1) ABCD chain matrix, 2) using hybrid couplers and 3) modal decomposition. Each measurement method provides a specific level of accuracy. The modal decomposition method can work up to 10GHz.

SPICE equivalent circuit model of common-mode chokes and the extraction …

Device Structure Effects On Electrical Crosstalk In Backwall Illuminated Cmos Compatible Photodiode Arrays, Paul Vernon Jansz

Theses : Honours

This research has made a comparative investigated of crosstalk in backside illuminated and frontside illuminated single junction photodiode and vertical double junction photodiode CMOS compatible pixels, using a commercial 2D device simulation package, SEMICAD DEVICE (1994). Comparison of pixel total, electron and hole quantum efficiency response and Absorption Volume data is undertaken. This is so that the underlying carrier drift-diffusion dynamics responsible for optimal pixel response resolution may be qualitatively understood, allowing prediction of even more optimal photodiode pixel configurations. The effect of varying the double junction and single junction photodiode pixel's geometry on response resolution is considered. Only for …

Adaptive Baseband Predistortion For Rf Power Amplifier Linearization., Laura Faus-Ferrer

Theses

In order to make use of spectrally efficient linear modulation methods for mobile communications, it is necessary to linearise the underlying RF power amplifier (PA). A number of techniques for linearizing a PA have been studied, focusing on the Adaptive Baseband Predistortion. The work is centred on the research concentrates on the analysis of different algorithms, their simulation using MatLab, and implementation of a predistorter as a subsystem of a prototype Cartesian based transmitter.

The thesis describes the typical architecture of a transceiver with an emphasis on the nonlinear analysis. Cavers’ algorithm has been examined in terms of its computational …

Modern Control Techniques For Induction Machines In High-Performance Adjustable-Speed Drives, Pat Cronin

Theses

Induction Motors (IM’s) are increasingly being considered for and used in high-performance motor drive (HPMD) systems. Their application has only gained acceptance since the 1970’s with the advent of vector control, microprocessors and improvements in power converter technology. D.C. motors were traditionally the preferred choice in HPMD systems. The main reasons for IM acceptance in HPMD systems are ruggedness, durability, low maintenance, cost, and small size by comparison with D.C. motors.

Alternating current asynchronous motors of the IM type are considered to be the universal workhorses of the manufacturing industry. It has been estimated that they are used in seventy …