Electrical and Computer Engineering Commons^™

Effects Of Temperature On The Proton Diffusion Of Doped Ni(Oh)2, Jian-Hua Liu, Jing-Wu Yang, Zhi-Yuan Tang

Journal of Electrochemistry

The Chronoamperometry of powder spherical Ni(OH)₂ microelectrode was used to study the proton diffusion coefficients of Ni(OH)₂. The proton diffusion coeefficients and the apparent diffusion active energy in anode and cathode processes at different temperature were obtained. Compared with pure Ni(OH)₂, the apparent diffusion active energy (E_a) of Ni(OH)₂ doped with Co and Co + Zn was decreased and the diffusion constant (D_o) was increased in the anode and the cathode processes, respectively, the effect of Co was greater. In contrast, for Ni(OH)₂ doped with Zn, its E_{a …}

Study On The Effect Of Sodium Ion On Cycle Performance Of Lithium/Improved Graphite Lithium Ion Cell, Wen-Huang Huang, Yu-Shun Yan, Chun-Rong Wan, Chang-Yin Jiang

Journal of Electrochemistry

The different concentration of Na⁺ was introduced into the non-aqueous eletrolyte system EC/DEC/LiClO 4 with 4A molecular sieve and lithiated 4A molecular sieve, by which the trace amount of water was removed. The concentrations of Na⁺ and Li⁺ were determined by atomic adsorption spectrometry. The cycle performance of lithium/improved graphite cells was then examined by charging and discharging under the constant electric current. The results demonstrated that the cycle performance of the cells was destroyed by the high concentration of Na⁺ under the small electric current. With the increase of electric current the cell became less …

Accumulation Hole Layer In P-Gan/Algan Heterostructures, M. S. Shur, A. D. Bykhovski, R. Gaska, J. W. Yang, Grigory Simin, M. A. Khan

Faculty Publications

We present the results on piezoelectric and pyroelectricdoping in AlGaN-on-GaN and GaN-on-AlGaN heterostructures and demonstrate p-GaN/AlGaN structures with accumulation hole layer. Our results indicate that polarization charge can induce up to 5×10¹³ cm⁻² holes at the AlGaN/GaN heterointerfaces. We show that the transition from three-dimensional (3D) to two-dimensional (2D) hole gas can be only achieved for hole sheet densities on the order of 10¹³ cm⁻² or higher. At lower densities, only 3D-hole accumulation layer may exist. These results suggest that a piezoelectrically induced 2D-hole gas can be used for the reduction of the base spreading resistance …

Fdtd Modeling Of Lumped Ferrites, Min Li, Xiao Luo, James L. Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

Implementing ferrites in finite-difference time-domain (FDTD) modeling requires special care because of the complex nature of the ferrite impedance. Considerable computational resources and time are required to directly implement a ferrite in the FDTD method. Fitting the ferrite impedance to an exponential series with the generalized-pencil-of-function (GPOF) method and using recursive convolution is an approach that minimizes the additional computational burden. An FDTD algorithm for a lumped ferrite using GPOF and recursive convolution is presented herein. Two different ferrite impedances in a test enclosure were studied experimentally to demonstrate the FDTD modeling approach. The agreement is generally good.

Circular Optimal Trade-Off And Distance-Classifier Correlation Filters, Samuel Peter Kozaitis, Sila Thangwaritorn

Electrical Engineering and Computer Science Faculty Publications

We use circular versions of advanced distortion-invariant filters such as optimal trade-off synthetic discriminant function and distance classifier correlation filters to obtain rotation invariance with an optical correlator. The filter noise performance is compared using a common measure of probability of error because the filters have different characteristics. The filters are real-valued so they can be implemented on a variety of SLMs. The circular symmetry of the filters significantly decreases their computational requirement.

Dc Power Bus Modeling In High-Speed Digital Designs Including Conductor And Dielectric Losses, Jun Fan, Hao Shi, James L. Knighten, James L. Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

Power bus design is a critical aspect in high-speed digital circuit designs. A circuit extraction approach based on a mixed-potential integral equation formulation is presented herein to model arbitrary multilayer power bus structures including vertical discontinuities associated with surface mount (SMT) decoupling capacitor interconnects. Both conductor and dielectric losses are incorporated, and included into the first principles formulation. The agreement of modeling and measurements demonstrates its effectiveness and utilization in power bus designs.

A Common-Mode Current Measurement Technique For Emi Performance Evaluation Of Pcb Structures, Xiaoning Ye, David M. Hockanson, James L. Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

An experimental technique that measures the common-mode current on a cable attached to a DUT for assessing EMI performance is introduced herein. The technique was applied to evaluate the EMI performance of a module-on-backplane configuration with different connectors and different connector pin-outs.

Emi Resulting From A Signal Via Transition Through Dc Power Bus-Effectiveness Of Focal Smt Decoupling, Wei Cui, Xiaoning Ye, Bruce Archambeault, Doug White, Min Li, James L. Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

Signal vias are commonly used in multilayer printed circuit board (PCB) design. For a signal via transitioning through the internal power and ground planes, the return current has to jump from one reference plane to another reference plane. The discontinuity of the return current at the via excites the power and ground planes, and results in power bus noise, and can produce an EMI problem as well. Numerical methods, such as finite-difference time-domain (FDTD), moment methods (MoM), and partial element equivalent circuit (PEEC), were employed herein to study this problem. The modeled results were supported by the measurements. In addition, …

Emi Reduction From Airflow Aperture Arrays Using Dual-Perforated Screens And Loss, Min Li, Joe Nuebel, James L. Drewniak, Todd H. Hubing, Richard E. Dubroff, Thomas Van Doren

Electrical and Computer Engineering Faculty Research & Creative Works

Airflow perforations in shielding enclosures can act as apertures facilitating the coupling from internal sources to external electromagnetic interference (EMI). This EMI radiation for single- and dual-screen configurations was studied herein experimentally and with finite-difference time-domain (FDTD) modeling. A general EMI reduction of more than 20 dB was achieved for dual-perforated screens spaced 1 cm apart when compared to EMI for a single perforated screen. However, in the dual-screen case, the space between the screens can act as a thin cavity, which, in turn, can lead to significant radiation at distinct angles. Damping the resonances by loading the space between …

Rotation-Invariant Synthetic Discriminant Function Filter For Pattern Recognition, Vahid R. Riasati, Partha P. Banerjee, Mustafa A. G. Abushagur, Kenneth B. Howell

Electrical and Computer Engineering Faculty Publications

The ring synthetic discriminant function (RSDF) filter for rotation-invariant response is discussed for pattern recognition. This method uses one half of a slice of the Fourier transform of the object to generate the transfer function of the filter. This is accomplished by rotating the one half of a slice in the Fourier domain through 2π rad about the zero-frequency point of the Fourier plane. This filter has the advantage of always matching at least one half of a slice of the Fourier transform of any rotation of the image. An analytical discussion of the filter construction and correlation results are …

3d Outside Cell Interference Factor For An Air-Ground Cdma ‘Cellular’ System, David W. Matolak

Faculty Publications

We compute the outside-cell interference factor of a code-division multiple-access (CDMA) system for a three-dimensional (3-D) air-to-ground (AG) "cellular-like" network consisting of a set of uniformly distributed ground base stations and airborne mobile users. The CDMA capacity is roughly inversely proportional to the outside-cell interference factor. It is shown that for the nearly free-space propagation environment of these systems, the outside-cell interference factor can be larger than that for terrestrial propagation models (as expected) and depends approximately logarithmically upon both the cell height and cell radius.

Multilevel Coded Modulation For Unequal Error Protection And Multistage Decoding—Part Ii: Asymmetric Constellations, Motohiko Isaka, Marc P. C. Fossorier, Robert H. Morelos-Zaragoza, Shu Lin, Hideki Imai

Faculty Publications

In this paper, multilevel coded asymmetric modulation with multistage decoding and unequal error protection (UEP) is discussed. These results further emphasize the fact that unconventional signal set partitionings are more promising than traditional (Ungerboeck-type) partitionings, to achieve UEP capabilities with multilevel coding and multistage decoding. Three types of unconventional partitionings are analyzed for asymmetric 8-PSK and 16-QAM constellations over the additive white Gaussian noise channel to introduce design guidelines. Generalizations to other PSK and QAM type constellations follow the same lines. Upper bounds on the bit-error probability based on union bound arguments are first derived. In some cases, these bounds …

Maintenance Registers With Boundary Scan Interface, Shianling Wu, Ramesh Karri, Charles Eugene Stroud

Electrical and Computer Engineering Faculty Patents

Concurrent Fault Detector Circuits (CFDCs) are test components of a main system, e.g. an Application Specific Integrated Circuit, and provide the results of the tests in parallel to at least one Error Source Register (ESR). Instead of reading out the ESR in parallel, its contents are copied to a serial shadow register so the contents can be read out in series to an error correcting application, thus reducing the number of output pins and the burden on resources of the main system. The ESR's receipt and transfer of information is under the control of a Boundary Scan Interface. In one …

Steady State Operating Characteristics Of Hybrid Loaded Resonant Power Converter, Taufik

Electrical Engineering

No abstract provided.

Bulk Micromachining Of Silicon For Moems Prototype, Sung-Dong Suh

Doctoral Dissertations

In this dissertation, the optical application of silicon micromachining technology was investigated in order to create the three-dimensional microstructures that can be used as the components for the MOEMS prototype. These microstructures were designed and fabricated by utilizing corner compensation techniques and silicon bulk micromachining technologies. The fabricated microstructures are silicon mirror arrays that have a 1250 μm etch depth and through-holes across the OE-MCM substrate that has sixteen-fan-out OCDN on front side and a 1mm thickness.

Guided-wave OCDN on MCMs are designed and fabricated to meet the high-speed clocking requirements of next-generation digital systems through a realization of superior …

Kinetics Of Laser Chemical Vapor Deposition Of Carbon And Refractory Metals, Feng Gao

Doctoral Dissertations

Three-dimensional laser chemical vapor deposition (3D-LCVD) has been used to grow rods of carbon, tungsten, titanium, and hafnium from a variety of hydrocarbons and metal halide-based precursors. A novel computerized 3D-LCVD system was designed and successfully used in the experiments. A focused Nd:Yag laser beam (λ = 1.06 μm) was utilized to locally heat up a substrate to deposition temperature. The rods, which grew along the axis of the laser beam, had a typical diameter of 30–80 μm and a length of about 1 mm. The precursors for carbon deposition were the alkynes: propyne, butyne, pentyne, hexyne, and octyne. Propyne …

Cramer-Rao Bound And Optimal Amplitude Estimator Of Superimposed Sinusoidal Signals With Unknown Frequencies, Shaohui Jia

Doctoral Dissertations

This dissertation addresses optimally estimating the amplitudes of superimposed sinusoidal signals with unknown frequencies. The Cramer-Rao Bound of estimating the amplitudes in white Gaussian noise is given, and the maximum likelihood estimator of the amplitudes in this case is shown to be asymptotically efficient at high signal to noise ratio but finite sample size. Applying the theoretical results to signal resolutions, it is shown that the optimal resolution of multiple signals using a finite sample is given by the maximum likelihood estimator of the amplitudes of signals.

Efficient Algorithms And Implementations For Signal Processing, Changbai Xiao

Doctoral Dissertations

A scheme is presented to regain a finite number of lost samples from a Nyquist-rate-sampled band-limited signal f of finite energy by replenishing new sample values of the same number. The result can also be viewed as the solution to a special non-uniform sampling problem.

A scheme is also presented to recover a band-limited function f of finite energy from its sampling values on real sequences with an accumulation point. The result given here can also be viewed as an approach to the extrapolation problem of determination a band-limited function in terms of its given values on a finite interval. …

Unmanned Research Vehicle (Urv): Development, Implementation, & Flight Test Of A Mimo Digital Flight Control System Designed Using Quantitative Feedback Theory, Constantine H. Houpis, Steven J. Rasmussen

Faculty Publications

The Quantitative Feedback Theory (QFT) design technique, which has the ability to bridge the gap between theory and the real-world control design problem, is utilized in the design of a MIMO digital flight control system for an unmanned research vehicle (URV) that is presented in this paper. The design illustrates how the real-world knowledge of the plant to be controlled and the desired performance specifications can be utilized in trying to achieve a successful robust design for a nonlinear control problem. This paper presents some of the issues involved in developing, implementing, and flight testing a flight control system (FCS) …

A Cmos Chaotic Oscillator, Boonsin Chansilp

Masters Theses

A chaotic oscillator may be used as the basic component of an associative memory (AM). An AM is capable of pattern separation and noise reduction. Chua's circuit is a widely used chaotic oscillator. This circuit consists of a nonlinear resistor, two capacitors, an inductor and a resistor. A discrete implementation of Chua's circuit may be built using operational amplifiers, resistors, diodes, or discrete bipolar transistors. CMOS integrated circuit technology provides the opportunity for a compact implementation which enables construction of systems requiring a large number of oscillators. This thesis develops an integrated circuit design based on previous work performed by …

Pulsed Optoacoustics In Solids, Zibiao Wei

Electrical & Computer Engineering Theses & Dissertations

Optoacoustic techniques are widely used to probe and characterize target materials including solids, liquids and gases. Included in such applications are diagnoses of thin films and semiconductor materials. The need to obtain greater spatial resolution requires the generation of shorter optoacoustic pulses. For such pulses, non-thermal effects may be quite important. On the other hand, even when an optoacoustic pulse is generated by an initially non-thermal technique, the thermal aspects become important in its evolution and propagation. The research undertaken in this Ph.D. dissertation included the generation and detection of optoacoustic signals through the thermal elastic mechanism. Several applications in …

Application Of Linear Matrix Inequalities In The Control Of Smart Structural Systems, Sridhar Sana, Vittal S. Rao

Electrical and Computer Engineering Faculty Research & Creative Works

Natural frequency variations, unmodeled dynamics and control input constraints are some of the major problems in the design of controllers in smart structural systems. The performance and robustness of the closed-loop system are often constrained by the limited actuation force available from Lead Zirconate Titanate (PZT) actuators. Hence, it is desirable to design controllers to maximize the performance and robustness without violating the control input constraints. In this paper, we give a methodology for designing output feedback robust controllers for smart structural systems using Linear Matrix Inequalities (LMIs). A procedure is developed to incorporate the real parameter uncertainty resulting from …

Theory Of Sic Schottky Barrier Conduction And Model Analysis For Diode Breakdown With And Without Screw Dislocations, Lifeng Zheng

Electrical & Computer Engineering Theses & Dissertations

Silicon Carbide is a very promising candidate for applications in high-power, high-temperature, and high-radiation conditions under which conventional semiconductors cannot perform adequately. However, the SiC processing technology has not yet reached maturity. There is also limited knowledge of its physical and chemical characteristics, and its device behavior is not well understood. The aim of this thesis is to analyze two specific problems in the SiC area. The first issue involves the large discrepancy between experimental I - V characteristics of SiC Schottky diodes and their theoretical values. The observed data, especially at low voltages, is found to be orders of …

Nanofabrication Using Coulomb Crystals: Giving Shape To The Semiconductor Technology Roadmap, S. Bandyopedhyay, P. F. Williams

P. F. (Paul Frazer) Williams Publications

In 1959, Richard Feynman delivered a lecture with the title, “There is Plenty of Room at the Bottom.” The audience was attendees of the American Physical Society meeting at Caltech. What Feynman, a great seer, talked about was using progressively smaller structures for useful purposes such as storing bits of information.
He even offered a $1,000 (US) prize for anyone who could take the information on the page of a book and put in an area 1/25,000 times smaller in linear scale. In 1986, 26 years after Feynman offered the prize, it was won by a Stanford University graduate student. …

Decision Not To Build A Nuclear-Waste Incinerator: What Goes Up In Smoke?, Ibpp Editor

International Bulletin of Political Psychology

This article explores the political psychology of a decision not to build a nuclear-waste incinerator in the United States.

Adaptive Handoff Algorithms Based On Self-Organizing Neural Networks To Enhance The Quality Of Service Of Nonstationary Traffic In Hierarchical Cellular Networks, William S. Hortos

Electrical Engineering and Computer Science Faculty Publications

Third-generation (3G) wireless networks, based on a hierarchical cellular structure (HCS), support tiered levels of multimedia services. These services can be categorized as real-time and delay-sensitive, or non-real-time and delay-insensitive. Each call carries demand for one or more services in parallel; each with a guaranteed quality of service (QoS). Roaming is handled by handoff procedures between base stations (BSs) and the mobile subscribers (MSs) within the network. Metrics such as the probabilities of handoff failure, dropped calls and blocked calls; handoff transition time; and handoff rate are used to evaluate the handoff schemes, which also directly affect QoS. Previous researchers …

Separation Of Infrasound Signals Using Independent Component Analysis, Fredric M. Ham, Sungin Park, Joseph C. Wheeler

Electrical Engineering and Computer Science Faculty Publications

An important element of monitoring compliance of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) is an infrasound network. For reliable monitoring, it is important to distinguish between nuclear explosions and other sources of infrasound. This will require signal (event) classification after a detection is made. We have demonstrated the feasibility of using neural networks to classify various infrasonic events. However, classification of these events can be made more reliably with enhanced quality of the recorded infrasonic signals. One means of improving the quality of the infrasound signals is to remove background noise. This can be carried out by performing signal separation using …

Profiling The Performance Of Tcp/Ip On Windows Nt, P. Xie, M. Liu, J. Harris, C. Scheiman

Electrical Engineering

This paper presents detailed network performance measurements of a prototype implementation of the TCP/IP network software on Windows NT. The measurements include latency, throughput, and CPU utilization of the protocol stack and for some key operations within the stack

A Conformal Finite Difference Time Domain (Cfdtd) Algorithm For Modeling Perfectly Conducting Objects, Wenhua Yu, Raj Mittra, Dean Arakaki, Douglas H. Werner

Electrical Engineering

In this paper, the authors present a new and robust conformal Finite Difference Time Domain (FDTD) algorithm for the accurate modeling of perfectly conducting objects with curved surfaces and edges. We illustrate the application of this approach by analyzing a number of representative antenna and cavity problems. These include a quarter wave monopole mounted on a perfectly conducting elliptic disk, a circular patch antenna, and a cylindrical cavity. We validate the me~od by comparing the results for the pattern, impedance and resonant frequency, etc., with those derived by using other techniques.

A Technique For Analyzing Radiation From Conformal Antennas Mounted On Arbitrarily-Shaped Conducting Bodies, Dean Arakaki, Douglas H. Werner, Raj Mittra

Electrical Engineering

This paper presents an efficient method to solve the problem of radiation from conformal aperture and microstrip antennas mounted on arbitrarily-shaped conducting bodies. The method, based on the surface equivalence and reciprocity principles, uses a combination of the Finite Difference Time Domain (FDTD) and Method of Moments (MoM) techniques to substantially improve the computational efficiency of the radiation pattern calculation. When the geometry and location of the radiating element are modified, only a small portion of the overall analysis requires re-simulation. This leads to a significant improvement in computational efficiency over presently-used techniques, and can substantially improve design efficiency when …