Engineering Commons^™

Maximum Likelihood Estimation Of Exponentials In Unknown Colored Noise For Target In Identification Synthetic Aperture Radar Images, Matthew P. Pepin

Theses and Dissertations

This dissertation develops techniques for estimating exponential signals in unknown colored noise. The Maximum Likelihood ML estimators of the exponential parameters are developed. Techniques are developed for one and two dimensional exponentials, for both the deterministic and stochastic ML model. The techniques are applied to Synthetic Aperture Radar SAR data whose point scatterers are modeled as damped exponentials. These estimated scatterer locations exponentials frequencies are potential features for model-based target recognition. The estimators developed in this dissertation may be applied with any parametrically modeled noise having a zero mean and a consistent estimator of the noise covariance matrix. ML techniques …

Study Of Stress In Microelectronic Materials By Photoelasticity, Hancheng Liang

Dissertations

The study of stress is playing an important role in microelectronic technology. In comparison with other techniques, the photoelasticity technique has the advantages of having high spatial resolution and high sensitivity. It can be used in qualitative observation in real-time and quantitative determination of stress distribution in the microelectronic materials and devices.

This dissertation presents a systematic study of photoelastic stress analysis in microelectronic materials and devices, ranged from theoretical study to practical system setup, from measurement methods to their applications. At first, based on the detailed survey on the piezo-optic properties of the crystals used in microelectronics, we apply …

Detecting Stress And Fatigue Cracks, Christian J. Huber, R. Zoughi

Electrical and Computer Engineering Faculty Research & Creative Works

Discoveries in using open ended rectangular waveguides for microwave surface crack detection and sizing have generated interest. The foundation, potential, advantages and disadvantages of this methodology, developed at the Applied Microwave Nondestructive Testing Laboratory in the Electrical Engineering Department at Colorado State University, are discussed. Microwave techniques in general and this particular approach offer certain unique advantages that can advance the state of the art of fatigue/surface crack detection. The basic features and capabilities of this technique have been theoretically and experimentally investigated these past few years. However, more developmental work is needed to bring this technique from the laboratory …

Generation Of Synthetic-Focus Images From Pulse-Echo Ultrasound Using Difference Equations, Daryl G. Beetner, R. Martin Arthur

Electrical and Computer Engineering Faculty Research & Creative Works

To produce a complete-dataset, pulse-echo image requires a knowledge of the time of flight (TOF) from each source to each sensor in the transducer array for each site to be imaged. Increasing the speed of TOF calculation is important in adaptive-focus schemes. The authors determined TOF more rapidly than via direct calculation by representing TOF surfaces by two-dimensional (2-D), positive-integer-degree polynomials implemented in their forward-difference form. Errors which accumulate due to the use of a difference equation depend on the degree of the polynomial and on the size of the image. The number of bits needed to address echo samples …

Infrared Quarter-Wave Reflection Retarders Designed With High-Spatial-Frequency Dielectric Surface-Relief Gratings On A Gold Substrate At Oblique Incidence, Jian Liu, Rasheed M.A. Azzam

Electrical Engineering Faculty Publications

One- and two-dimensional high-spatial-frequency dielectric surface-relief gratings on a Au substrate are used to design a high-reflectance quarter-wave retarder at 70° angle of incidence and 10.6-μm light wavelength. The equivalent homogeneous anisotropic layer model is used. It is shown that equal and high reflectances (>98.5%) for the p and the spolarizations and quarter-wave retardation can be achieved with two-dimensional ZnS surface-relief gratings. Sensitivities to changes of incidence angle, light wavelength, grating filling factor, and grating layer thickness are considered.

Real-Time Visual Speech Articulation Training Aid, Neiyer S. Correal

Electrical & Computer Engineering Theses & Dissertations

A real-time visual articulation training aid has been implemented. It provides instantaneous visual feedback of vowel and stop-consonant production on a computer screen. The vowel training system corresponds to an improved floating-point implementation of a previous fixed-point system developed by Beck (1992). The new implementation provides better accuracy and an approximate five-fold increase in speed. Acoustic features computed from global short-time spectral shape are used for classification of vowels. Temporal spectral trajectories timed to begin with burst onset are used for stop consonants. A neural network is used to transform measurements of auditory stimuli from the feature space to a …

Monte Carlo Simulations Of Photoemission Characteristics From Gaas And Diamond, Abhishek Srivastava

Electrical & Computer Engineering Theses & Dissertations

Monte Carlo based numerical simulations were performed to study photoemission from GaAs and diamond. The central goal was to assess the potential for NEA photoemission from diamond, and to predict its characteristics. The GaAs material system was also included in the simulation study to provide: (i) calibration and validation of the numerical model developed by carefully matching the simulation results with available experimental data, and (ii) quantitative comparisons between the response characteristics of diamond and the better known GaAs system.

Predictions of the energy distribution, temporal response and angular distribution of emitted electrons were obtained. Effects of various parameters, such …

Resource/Dataflow Graph Operating System Development, Sriram J. Coimbatore

Electrical & Computer Engineering Theses & Dissertations

Implementation of a new dataflow schedule model is the objective of this thesis. The dataflow model algorithm called the resource/dataflow graph model is implemented on a peer-to-peer communication network comprising of six personal computers. This dataflow model is implemented making use of an earlier dataflow model called ATAMM (Algorithm to Architecture Mapping Model) developed by ODU and National Aeronautics and Space Administration (NASA). Development issues include modification of the RDFG testbed operating system and a scheme to transfer data buffers using the ethernet channel from one processor to another processor. This, in turn, equips each sub-module of an application with …

Nlo Waveguide "And" Switch And Method Therefor, John J. Kester, Iyad A. Dajani, Peter M. Ranon, Thomas G. Alley

AFIT Patents

Method and apparatus are provided for NLO switching by first providing a phase-matched SHG grating which outputs a reinforced SHG beam only when two input beams of frequency (ω) are present in two modes of such wg. The so encoded NLO switch is operated by directing at least two input pulsed laser beams of frequency (ω) into the two modes of the wg to generate a reinforced pulsed output SHG beam and output same from the wg in an NLO switching process. The two input beams desirably have a separate pulse train and the spatial and temporal overlap of the …

Determination Of The Refractive Index And Thickness Of Transparent Pellicles By Use Of The Polarization-Independent Absentee-Layer Condition, Y. Cui, R. M.A. Azzam

Electrical Engineering Faculty Publications

The refractive index and the thickness of a transparent pellicle are determined when the pellicle is placed between two vertical crossed polarizers and rotated in the horizontal plane. The transmission axes of the polarizers are neither parallel nor perpendicular to the plane of incidence. The light transmitted through the crossed polarizers reaches a minimum when the pellicle satisfies the absentee-layer condition. The refractive index and the film thickness are obtained from the pellicle orientation angles under such a condition.

Electromagnetic Scattering From Semi-Infinite Planar Arrays, Peter J. Collins

Theses and Dissertations

A hybrid method of moments (MM) based numerical model for the electromagnetic scattering from large finite by infinite planar slot arrays is developed. The method incorporates the novel concept of a physical basis function (PBF) to dramatically reduce the number of required unknowns. The model can represent a finite number of slot columns with slots oriented along the infinite axis, surrounded by an arbitrary number of coplanar dielectric slabs. Each slot column can be loaded with a complex impedance, allowing one to tailor the edge currents to provide a desired echo width pattern. The surface equivalence theorem is used to …

Globally Optimal Periodic Robot Joint Trajectories, Daniel J. Simon

Electrical and Computer Engineering Faculty Publications

This paper presents a new method for the planning of robot trajectories. The method presented assumes that joint-space knots have been generated from Cartesian knots by an inverse kinematics algorithm. The method is based on the globally optimal periodic interpolation scheme derived by Schoenberg, and thus is particularly suited for periodic robot motions. Of all possible periodic joint trajectories which pass through a specified set of knots, the trajectory derived in this paper is the ‘best’. The performance criterion used is the integral (over one period) of a combination of the square of the joint velocity and the square of …

Hybrid Kalman / Minimax Filtering In Phase-Locked Loops, Daniel J. Simon, Hossny El-Sherief

Electrical and Computer Engineering Faculty Publications

A method of combining Kahnan filtering and minimax filtering is proposed and demonstrated in an application to phase-locked loop design. Kalman filtering suffers from a lack of robustness to departures from the assumed noise statistics. Minimax filtering, however, has the drawback of ignoring the engineer's (admittedly incomplete) knowledge of the noise statistics. It is shown in this paper that hybrid Kalman/minimax filtering can provide the “best of both worlds” . Phase-locked loop filter design is used in this paper to demonstrate an application of hybrid estimation.

Real-Time Optically Processed Face Recognition System Based On Arbitrary Moiré Contours, Rafael A. Andrade, Bernard R. Gilbert, Donald W. Dawson, Chris L. Hart, Samuel Peter Kozaitis, Joel H. Blatt

Electrical Engineering and Computer Science Faculty Publications

We demonstrate a hybrid electronic-optical real-time system that performs 3-D face recognition. We constructed custom reference gratings that formed a desired moire pattern when mixed with images of structurally illuminated faces. The moiré patterns could be in any form such as, equal depth contours, error maps, or any arbitrary pattern. We demonstrate video methods to generate such error maps in real time, thus developing a real-time automated face recognition system based on the optical processing of arbitrary moiré contours. We chose the moiré pattern to be in the form of a Fresnel zone plate, which is displayed on a liquid …

An Empirical Comparison Of Area-Universal And Other Parallel Computing Networks, Ronald I. Greenberg, Lee Guan

Computer Science: Faculty Publications and Other Works

This paper provides empirical comparison of the communication capabilities of two area-universal networks, the fat-tree and the fat-pyramid, to the popular mesh and hypercube networks for parallel computation. While area-universal networks have been proven capable of simulating, with modest slowdown, any computation of any other network of comparable area, prior work has generally left open the question of how area-universal networks compare to other networks in practice. Comparisons are performed using techniques of throughput and latency analysis that have previously been applied to k-ary n-cube networks and using various existing models to equate the hardware cost of the networks being …

Maximum Likelihood Estimation Of Exponentials In Unknown Colored Noise For Target Identification In Synthetic Aperture Radar Images, Matthew P. Pepin

Theses and Dissertations

This dissertation develops techniques for estimating exponential signals in unknown colored noise. The Maximum Likelihood (ML) estimators of the exponential parameters are developed. Techniques are developed for one and two dimensional exponentials, for both the deterministic and stochastic ML model. The techniques are applied to Synthetic Aperture Radar (SAR) data whose point scatterers are modeled as damped exponentials. These estimated scatterer locations (exponentials frequencies) are potential features for model-based target recognition. The estimators developed in this dissertation may be applied with any parametrically modeled noise having a zero mean and a consistent estimator of the noise covariance matrix. ML techniques …

An Esr Study Of Free Radicals In Electroreduction Process Of Allyl Alcohol, Jindong Zhang, Yafei Kuang, Shukun Huang, Naixian Xie, Fengzhen Wang, Dewen Chen

Journal of Electrochemistry

Electrochemical-ESR technique with spin trap phenyl-t-butyl nitrone(PBN)was used to study the intermediates of electroreduction of allyl alcohol at platinized platinum electrode in acidic alcohol-aqua solution. Hydrogen and allyl group and(or)propyl group radicals were identified by a hyperfine spectrum of the radical adducts, and that provided a direct evidence for the presence of these radicals in the electroreduction of allyl alcohol.

A Study On Solid Polymer Electrolyte Fuel Cell, Hongfeng Xu, Ming Han, Baolian Yi, Xinge Zhang, Shanhai Ge

Journal of Electrochemistry

Solid polymer electrolyte fuel cell (SPEFC) show promise of a high level of performance in the present fuel cell. In this paper, we report the method of SPEFC electrode preparation,and the effects of temperature, pressure and gas flow rate on the performance.

A Study On Electrochemical Oxidation Of Reduced Nicotinamide Coenzyme Nadh In Organic Media, Fangzu Yang, Huihuang Wu, Shukai Xu, Shaomin Zhou

Journal of Electrochemistry

The behaviour of electrochemical oxidation of the reduced nicotinamide coenzyme NADH on glassy carbon was studied and some kinetic parameters were measured by means of voltammometry in the N-dimethylformamide (DMF) and 1,4-dioxane media respectively. The eletrochemical oxidation of NADH shows completely irriversable both in the two solvents,and the diagnostic experiments support that the process involves a fast chemical step.The oxidation rate and the diffusion coefficient of NADH in DMP are smaller than those in 1,4-dioxane, but the response current is more stable in DMF. The experimental results are discussed by solvent effects.

Studies On The Charge And Discharge Reaction Of Li/Lini0.3Co0.7O2 Battery, Fupjng Zhang

Journal of Electrochemistry

The charge and discharge reaction of Li/LiNi_0.3Co_0.7O₂ battery have been studied by using CV,CT,XRD and GCP. It is shown that the discharge capacity of the cell reaches 120-140 mA·h·g^-1 in the 4.30-3.00 V in 1 mol/L LiClO₄/PC electrolyte system. The discharge mechanism involve a two-step Li⁺ intercalation reaction. The thermodynamic data such as ΔG,ΔS, ΔH, of the reaction are given. Furthermore, the changes of the D or σ_i of Li⁺ with its composition have been discussed.

Study On The Growth Process Of Lead Dioxide On Lead-Antimony Electrodes By Impedance Tracing Method, Guolin Wei, Hongxin Yang, Jiarong Wang

Journal of Electrochemistry

The growth process of PbO₂ formed by the oxidation of PbSO₄ in the anodic film on lead-(1,3,5,7)wt% antimony electrodes was investigated with impedance tracing method of single frequency and the current-time transient method. The influence of antimony on this process was studied.The simulation curves obtained for capacity-time transients fit the experimental results very well. It has been shown that the mentioned growth process is a two-dimentional instantaneous nucleation and growth process. Antimony will inhibit the growth of PbO₂ nucleus but enhance its nucleation.

Real-Time Range Image Segmentation Using Adaptive Kernels And Kalman Filtering, Fred W. Depiero, Mohan M. Trivedi

Electrical Engineering

Segmentation is a fundamental process affecting the overall quality and utility of a machine vision system. Range Profile Tracking (RPT) is a systematic approach for stable, accurate and high speed segmentation of range images that is based on Kalman filtering. Tests of RPT have produced stable decompositions of second order surfaces bounded by jump and crease discontinuities, having a volumetric error of a few percent, in under 6 sec. for a wide variety of conditions. Results from over 900 tests on synthetic scenes and 150 real range images are presented.

Simple Rail-To-Rail Constant-Transconductance Input Stage Operating In Strong Inversion, Vladimir I. Prodanov, Michael M. Green

Electrical Engineering

A CMOS op-amp input and gain stage suitable for low voltage operation are introduced. The input stage operates in strong inversion and has common-mode range beyond rail-to-rail. It uses two complementary differential pairs connected in parallel. The common-mode dependent current biasing employs only four transistors, does not require additional voltage references, current switches and/or current mirrors and does not increase the minimum required supply voltage. The variation of the net transconductance is approximately 15% over the entire common-mode range. The gain-stage has constant output resistance. In addition it reduces the variation of the net transconductance due to variations in μn/μp …

Design And Implementation Of A Model For Authoring And Presenting Interactive Multimedia Documents, Vibha Mukul Nayyar

Dissertations and Theses

Multimedia technology enables direct manipulation of multiple media such as text, image, audio, and video, all integrated into one entity - the multimedia document. Interactive multimedia documents integrate text, images and continuous media such as audio and video, treat them as objects to be presented for a certain duration, and allow users to interact with the presentation. Authoring and presenting interactive multimedia documents imposes new requirements on document representation. We designed the interactive timeline model (ITM) for authoring and presenting interactive multimedia documents. We implemented the model and created a playback tool using the scripting language Tcl.

ITM uses an …

Fdtd Modeling Of Common-Mode Radiation From Cables, David M. Hockanson, James L. Drewniak, Todd H. Hubing, Thomas Van Doren

Electrical and Computer Engineering Faculty Research & Creative Works

Radiation from cables attached to printed circuit boards and shielding enclosures is among the primary concerns in meeting FCC Class A and B limits. The finite-difference time-domain (FDTD) method can be employed to model radiation from printed circuit boards and shielding enclosures with complex geometries, but difficulties in modeling wires and cables of arbitrary radii are encountered. Modeling the wire by setting the axial component of the electric field to zero in the FDTD method results in an effective wire radius that is determined by the mesh discretization. Neglecting the wire radius in applications, such as electromagnetic interference (EMI) or …

A Multi-Institutional Cooperative Approach To Power Engineering Education, Anil Pahwa, Kraig J. Olejniczak, S. D. Sughoff, Shelli K. Starrett, Mariesa Crow

Electrical and Computer Engineering Faculty Research & Creative Works

This paper describes the multi-institutional cooperative effort between the University of Missouri--Rolla, Kansas State University, and the University of Arkansas to develop two new courses in flexible power system control.

Experimental And Numerical Investigations Of Fundamental Radiation Mechanisms In Pcb Designs With Attached Cables, David M. Hockanson, Cheung-Wei Lam, James L. Drewniak, Todd H. Hubing, Thomas Van Doren

Electrical and Computer Engineering Faculty Research & Creative Works

Stacked-card and modules-on-backplane printed circuit board geometries are advantageous for conserving real-estate in many designs. Unfortunately, at high frequencies, current-driven noise sources may develop at the connector. The connector may effectively drive the daughter-card against the motherboard and attached cables, resulting in common-mode radiation. The connector geometry can be modified to reduce the level of the effective noise-source when high frequencies are routed between the mother-board and daughter-card. Current speeds and PCB board sizes result in geometries that are of significant dimensions in terms of wavelength at the upper frequency end of the signal spectrum. Geometries are then of sufficient …

Simulation And Measurement For Decoupling On Multilayer Pcb Dc Power Buses, Hao Shi, F. Yuan, Fei Sha, James L. Drewniak, Todd H. Hubing, Thomas Van Doren

Electrical and Computer Engineering Faculty Research & Creative Works

DC power bus decoupling of a multi-layer PCB is modeled by a combination of a lumped circuit model at low frequencies ( < 200 MHz), and a mixed-potential integral equation approach at high frequencies. In order to determine the lumped parameters of via interconnects, an effective procedure using a network analyzer has been developed to characterize the trace/via inductances/resistances. For an 8 inch × 10 inch ten-layer test board used in this study, the simulations show good agreement with the measurement. This method can lead to new design strategies of decoupling for multilayer PCB power buses.

A Comparison Of An Fdtd Thin-Slot Algorithm And Method Of Moments For Modeling Slots Near Corners, Kuang-Ping Ma, James L. Drewniak, Todd H. Hubing, Thomas Van Doren

Electrical and Computer Engineering Faculty Research & Creative Works

Subcellular FDTD algorithms for modeling thin slots in conductors have previously been developed. One algorithm that is based on a quasi-static approximation has been shown to agree well with experimental results for thin slots in planes. This FDTD thin-slot algorithm is compared herein with moment method results for thin slots near corners.

An Expert System Approach To Emc Modeling, Todd H. Hubing, James L. Drewniak, Thomas Van Doren, Navin Kashyap

Electrical and Computer Engineering Faculty Research & Creative Works

Existing computer software for EMC analysis can be divided into three categories. Analytical modeling codes employ closed form expressions to solve problems of general interest to EMC engineers or circuit designers. Numerical modeling codes use numerical techniques to solve Maxwell's equations subject to specific boundary conditions. EMC rule checkers search a design for features that violate basic EMC design guidelines. This paper outlines the relative advantages and limitations of each of these three approaches and describes an expert system EMC modeling approach. The new approach combines analytical models, numerical models, and EMC rule-checking in order to evaluate designs in much …