Engineering Commons^™

Satellite Attitude Control System Design Using Reaction Wheels, Bhanu Gouda, Brian Fast, Daniel J. Simon

Electrical and Computer Engineering Faculty Publications

No abstract provided.

Controller Tuning For Dc Motor Speed Control Using Genetic Algorithms, Saurabh Jain, Daniel J. Simon

Electrical and Computer Engineering Faculty Publications

No abstract provided.

Electrostatic Radio Frequency (Rf) Microelectromechanical Systems (Mems) Switches With Metal Alloy Electric Contacts, Ronald A. Coutu Jr.

Theses and Dissertations

RF MEMS switches are paramount in importance for improving current and enabling future USAF RF systems. Electrostatic micro-switches are ideal for RF applications because of their superior performance and low power consumption. The primary failure mechanisms for micro-switches with gold contacts are becoming stuck closed and increased contact resistance with increasing switch cycles. This dissertation reports on the design, fabrication, and testing of micro-switches with sputtered bi-metallic (i.e., gold (Au)-on-Au-(6.3at%)platinum (Pt)), binary alloy (i.e., Au-(3.7at%)palladium (Pd) and Au-(6.3at%)Pt), and ternary alloy (i.e., Au-(5at%)Pt-(0.5at%)copper (Cu)) contact metals. Performance was evaluated, in-part, using measured contact resistance and lifetime results. The micro-switches with …

A Tightly-Coupled Ins/Gps Integration Using A Mems Imu, Jonathan M. Neu

Theses and Dissertations

Micro-Electro-Mechanical Systems (MEMS) technology holds great promise for future navigation systems because of the reduced size and cost of MEMS inertial sensors relative to conventional devices. Current MEMS devices are much less accurate than standard inertial sensors, but they can still be useful. In this thesis, data was recorded from an inexpensive MEMS inertial measurement unit and integrated with GPS measurements using a tightly-coupled Kalman filter. The overall goal of this research is to investigate the usefulness of MEMS sensors for a small, real-time, low-cost INS/GPS integration. A golf cart was used to collect dynamic data, along with a commercial …

Exploiting Independent Filter Bandwidth Of Human Factor Cepstral Coefficients In Automatic Speech Recognition, Mark D. Skowronski, John G. Harris

Electrical and Computer Engineering Faculty Research & Creative Works

Mel frequency cepstral coefficients (MFCC) are the most widely used speech features in automatic speech recognition systems, primarily because the coefficients fit well with the assumptions used in hidden Markov models and because of the superior noise robustness of MFCC over alternative feature sets such as linear prediction-based coefficients. The authors have recently introduced human factor cepstral coefficients (HFCC), a modification of MFCC that uses the known relationship between center frequency and critical bandwidth from human psychoacoustics to decouple filter bandwidth from filter spacing. In this work, the authors introduce a variation of HFCC called HFCC-E in which filter bandwidth …

Network Anomaly Detection Using Management Information Base (Mib) Network Traffic Variables, Jun Li

Dissertations

In this dissertation, a hierarchical, multi-tier, multiple-observation-window, network anomaly detection system (NADS) is introduced, namely, the MIB Anomaly Detection (MAD) system, which is capable of detecting and diagnosing network anomalies (including network faults and Denial of Service computer network attacks) proactively and adaptively. The MAD system utilizes statistical models and neural network classifier to detect network anomalies through monitoring the subtle changes of network traffic patterns. The process of measuring network traffic pattern is achieved by monitoring the Management Information Base (Mifi) II variables, supplied by the Simple Network Management Protocol (SNMP) LI. The MAD system then converted each monitored …

Carrier Transport In Ge Nanowires And One Dimensional Si/Ge Heterojunctions, Eun Kyu Lee

Theses

Ge Nanowires (Ge NWs) on single crystal, (100) and (111) oriented n-type Si substrates were grown via the vapor-liquid-solid (VLS) mechanism and studied with respect to their electrical properties.

Using different contact geometries, direct current (DC) and alternating current (AC) electrical and photoelectrical measurements were carried out at room temperature to investigate electrical properties of Ge NWs and Ge NWs/Si substrate one-dimensional (1 D) heterojunctions (HJs). A rectifying junction behavior is observed at NWs/substrate interface, but many orders of magnitude greater AC conductance than DC in Ge NW volume is measured at high frequencies. The obtained experimental data are consistent …

Detection Of Denial Of Service Attacks Using Database Queries, Dmytro Zakhalyavko

Theses

In the current intrusion detection world, most intrusion detection systems output data into flat files. This project was conducted in order to improve intrusion detection data and alerts by writing them into a database system and analyzing them with SQL. A database plug-in was developed that helps to transition the data from an intrusion detection system to a database. Storing, analyzing, categorizing, and accessing data are major advantages and reasons for using databases in intrusion detection. Security analysts have to constantly perform the difficult task of sorting through a haystack of attack alerts, many of which turn out to be …

Spectrum Control And Iterative Coding For High Capacity Multiband Ofdm, Divaydeep Sikri

Theses

The emergence of Multiband Orthogonal Frequency Division Modulation (MB-OFDM) as an ultra-wideband (UWB) technology injected new optimism in the market through realistic commercial implementation, while keeping promise of high data rates intact. However, it has also brought with it host of issues, some of which are addressed in this thesis.

The thesis primarily focuses on the two issues of spectrum control and user capacity for the system currently proposed by the Multiband OFDM Alliance (MBOA). By showing that line spectra are still an issue for new modulation scheme (MB-OFDM), it proposes a mechanism of scrambling the data with an increased …

Testing A Quantum Computer, Marek Perkowski, Jacob D. Biamonte

Electrical and Computer Engineering Faculty Publications and Presentations

We address the problem of quantum test set generation using measurement from a single basis and the single fault model. Experimental physicists currently test quantum circuits exhaustively, meaning that each n-bit permutative circuit requires ζ x 2n tests to assure functionality, and for an m stage permutative circuit proven not to function properly the current method requires ζ x 2n x m tests as the upper bound for fault localization, where zeta varies with physical implementation. Indeed, the exhaustive methods complexity grows exponentially with the number of qubits, proportionally to the number of stages in a quantum circuit and directly …

Optimal Sampling For Single-Tone Frequency Estimation, Travis E. Oliphant

Faculty Publications

Single-tone frequency estimation from irregularly spaced samples is analyzed. The ratio of the Cramr-Rao Bound (CRB) for regularly spaced samples to the bound for irregularly spaced samples is presented and shown to be a globally convex function. It's minima and maxima over the domain of interest are identified which reveals that improvements in the CRB can be obtained using non-equally-spaced samples. For a given sampling density, the best estimates of frequency are obtained when half of the samples are taken at one end of the total available interval and the remaining samples are taken at the other end.

Synergisms Of Electric Or Electromagnetic Fields And Photodynamic Effects Induce Apoptosis And Necrosis Of Cancer Cells, Radeva Maria, Lambrera Maya, Angelova Plamena, Traitcheva Nelly, Berg Hermann

Journal of Electrochemistry

Weak pulsating sinusoidal electromagnetic fields (PEMF) have been applied to change membrane permeation and induction of apoptosis (necrosis). In the case of suspension of human cancer cells U-937 and K-562 inside of Helmholtz-coils the amplitude of PEMF B=10 and at 39mT (at 50 Hz) was combined gradually with the cytotoxic agent actinomycin-C on one hand with its novel photodynamic activity on the other.

Electrochemical Reduction Of Nitrobenzene On The Wc Electrode In Acidic Solution, Chun-An Ma, You-Qun Chu, Ying-Hong Zhu, Zhi-Hua Xu

Journal of Electrochemistry

The tungsten carbide (WC) electrode was constructed by using polyterafluoroethylene as binder. The electrochemical behavior of nitrobenzene on the WC electrode in acidic solution was investigated by cyclic voltammetry, linear scan method and chronoamperometry. Experimental results showed that WC electrode had good activity for the electrochemical reduction of nitrobenzene, and the electrode process was controlled by diffusion and electrochemical stepssimultaneously. The apparent active energy of the electrode process is 23.7kJ⋅mol^-1, while the active energy of the electrochemicalstep is 10.91kJ⋅mol^-1.

Solid State Synthesis And Electrocatalysis Of Pt/Moo3 For The Oxidation Of Methanol, Qing Wang, Yi-Ming Zhou, Yang Shao, Yi-Gang Ji, Juan Xu, Ya-Wen Tang, Tian-Hong Lu, Tao Shen

Journal of Electrochemistry

The electrocatalyst, Pt/MoO₃ synthesized by solid state reaction, was used for the oxidation of methanol in direct methanol fuel cells. The X-Ray diffraction and cyclic voltammetry were employed to investigate the performance of the material. It was shown that the typical diffraction peaks for Pt appeared in XRD. And a good electrocatalysis for methanol oxidation was observed. The peak potential of the methanol oxidation appeared at ca. 0.63V(vs.SCE) and the peak current density for the oxidation was 78.1 mA⋅cm^-2.

Study On An Intermediate Temperature Planar Solid Oxide Fuel Cell, Shao-Rong Wang, Wen-Xia Chen, Ting-Lian Wen, Jia-Di Cao, Zhi-Yi Lv, Da-Qian Wang

Journal of Electrochemistry

Tape cast method was applied to prepare green sheets of Ni/YSZ anode supported YSZ thin film. After isostatic pressure treatment and cosintering, the YSZ film on the Ni/YSZ anode was gas-tight dense, and 15~30 μm thick. The area of the composite film was over 100 cm². A Ce_0.8Sm_0.2O_1.9 (CSO) interlayer was sintered on to the YSZ electrolyte film to protect La_0.6Sr_0.4CoO₃ (LSCO) cathode from reaction with YSZ at high temperatures. The LSCO cathode layer was screen printed onto the CSO interlayer and sintered at 1200 ℃ for 3 …

Fabrication Of Solid Oxide Fuel Cells And Analysis Of Their Structure And Performance, Nai-Tao Yang, Bo Meng, Ru-Jun Yu, Xiao-Yao Tan

Journal of Electrochemistry

An intermediate temperature solid oxide fuel cell (IT-SOFC) was fabricated by co-copressing-sintering methods, and the electrolyte of Ce_0.8Gd_0.2O_1.9 (CGO) and cathode materials of La_0.6Sr_0.4Co_0.2Fe_0.8O_3-α (LSCF) were prepared by sol-gel method. The effect of preparation methods on the microstructure of the prepared fuel cells was analyzed by SEM . It shows that the cells prepared by the co-pressing/co-sintering method possess a dense electrolyte layer and a compact interface between electrolyte and anode but a curved configuration, while those prepared by the colloidal technique have a flat configuration …

A Dual-Cell Technique And Its Application In Electrocatalytic Study Of Pt-Ru Metals, Lei Su, Bing-Liang Wu

Journal of Electrochemistry

Two local electrochemical reactive interfaces are established using two strips of Nafion membrane separated each other, which are in contact with different surface regions of the same metal-sheet working electrode. One potentiostatis used to control thepotentialof one electrochemical reactive interface to generate adsorbed surface speciesand the other potentiostatto hold the potential of the second interface as a detector of the intermediate. The adsorbed surface species driven by the difference in surface concentration diffuses alongthe surface of the metal-sheet between both local electrochemical interfaces and can be detected at the second interface when they achieveover there.The surface diffusion coefficient of the …

Preparation And Electrochemical Performance Of New Composite Seperators For Lithium-Ion Batteries, Hu Cheng, Hong-Yan Du, Yong Yang

Journal of Electrochemistry

New composite seperators for lithium ion batteries were prepared by coating PEO mixed with nanosize SiO₂ onto microporous polypropylene(PP) seperators. Highly conductive electrolytes were prepared by soaking them in an electrolyte solution. With these composite separators, the lithium ion cell consisting of Li anode and LiNi_0.8Co_0.2O₂ cathode were assembled. The high initial discharge capacity and good capacity retention were obtained through the cell.

Synthesis Of (S)-3-Phenylpropane-2-Tert-Butoxycarbonylamino-1-Thiol And Its Electrochemical Behavior Self-Assembled On Gold, Ru Sun, Jian-Feng Ge, Mei Wang, Ren-Ao Gu

Journal of Electrochemistry

The synthesis of (S)-3-Phenylpropane-2-tert-butoxycarbonylamino-1-thiol(N-Boc-APT) from L-phenylalanine was reported. L-Phenylalanine was reduced to the corresponding amino alcohol, protection of the amino group using tert-butyl pyrocarbonate gave (S)-2-tert-butoxycarbonylamino-3-phenylpropane-1-ol, which was then O-mesylated and treated with potassium thioacetate in DMF to give 3-phenylpropane-2-tert- butoxycarbonylamino-1-etylmercapto. After the acetyl group was removed with ammonia in alcohol, the desired target molecular was obtained. The structure of intermediate and target molecular was conformed by IR and ¹HNMR. We made N-Boc-APT self-assemble-modificated gold electrode and investigated its electrochemical behavior. The CV results of methylene blue on nano-Au/N-Boc-APT SAM/Au electrode showed that nano-Au could speed this electron transfer …

Synthesis And Electrochemical Behavior Of Layered-Structure Limn1-XCrXO2, Jie Xiao, Hui Zhan, Yun-Hong Zhou

Journal of Electrochemistry

The Layered-structure LiMn_1-xCr_xO₂(x=0, 0.15) solid solution has been prepared by the rheological phase method. From the XRD results, undoped LiMnO₂ crystallized almost entirely in the orthorhombic phase while the structure of LiMn_0.85Cr_0.15O₂ belongs to monoclinic phase. TEM investigation shows that the final powder product consists of ultrafine spherical particles which are distributed homogeneously, with the average diameter ranging from 60 to 300nm. The initial discharge capacity of LiMn_0.85Cr_0.15O is much higher than that of undoped LiMnO₂. After 40 cycles, the capacity retention …

Lithium Insertion Into Tio2(B) Nanobelts Synthesized By The "Soft Chemical" Method, Cha-Geng Nie, Zheng-Liang Gong, Lan Sun, Juan Zuo, Yue-Kun Lai, Chang-Jian Lin

Journal of Electrochemistry

TiO₂(B) Nanobelts were synthesized by using the "Soft chemical"method. The products were characterized by means of transmission electron microscope(TEM), X-ray diffraction(XRD), Raman spectrum and energy dispersive spectrum(EDS). Galvanostatic charging and discharging tests showed that lithium-ion intercalation/deintercalation occurred reversibly in the TiO₂(B) nanobelts electrode, and a high capacity (265 mAh·g^-1) can be obtained. The results suggested that TiO₂(B) Nanobelts might be a promising negative electrode material of second Lithium battery.

Preliminary Study Of Speek Membranes For Direct Methanol Fuel Cells Application, Su-Zhen Ren, Zhen-Xing Liang, Xin-Sheng Zhao, Qin Xing, Gong-Quan Sun, Xue-Feng Yang

Journal of Electrochemistry

This paper describes the methanol permeability characterization of SPEEK membranes and their feasibility for DMFC application. The SPEEK membranes showed a significant lower methanol permeation than Nafion 115 determined from voltammetric methods. An increase in open circuit voltage was found in the performance of SPEEK membranes in DMFC. The power density of the cell using SPEEK membrane was considerably poorer than that of Nafion 115. If modified properly, the SPEEK membranes can be chosen for DMFC application based on this study.

Structural Graph Matching With Polynomial Bounds On Memory And On Worst-Case Effort, Fred W. Depiero

Electrical Engineering

A new method of structural graph matching is introduced and compared against an existing method and against the maximum common subgraph. The method is approximate with polynomial bounds on both memory and on the worst-case compute effort. Methods work on arbitrary types of graphs and tests with strongly regular graphs are included. No node or edge colors are needed in the methods; the common subgraph is extracted based in structural comparisons only. Monte Carlo trials are benchmarked with 100% additional (clutter) nodes. Results are shown to be typically within 1-2 nodes of the maximum common subgraph. Over 7500 test trials …

Electromagnetic Crosstalk Penalty In Serial Fiber Optic Modules, Xiaomin Jin, Keith D. Lystad, Musoke H. Sendaula

Electrical Engineering

Electromagnetic crosstalk poses a serious problem within today S advanced serial communication modules. A major detrimental effect is the degradation of receiver sensitivity in the presence of crosstalk noise. The mitigation of crosstalk penalty becomes increasingly more challenging as data rates increase for higher throughput and as module sizes shrink for increased port density. This paper is a study of the primary sources of crosstalk penalty in a 2.5 GB/s serial fiber optic transceiver and a 10Gb/s serial fiber optic transponder. A novel method for quantifying crosstalk penalty by observing a receiver’s bit-error-ratio (BER) versus transmitter to receiver signal phase …

Frequency Estimation Of Linear Fm Scatterometer Pulses Received By The Seawinds Calibration Ground Station, Spencer S. Haycock

Theses and Dissertations

The SeaWinds Calibration Ground Station (CGS) is a passive ground station used to receive and sample transmissions from the SeaWinds scatterometer. During post processing, the received transmissions are characterized in order to verify proper instrument operation and to eliminate error in satellite telemetry and in data products generated from processing SeaWinds data. Sources of instrument error include uncertainties in transmitted power, pulse timing, and carrier frequency drift. Identifying these errors prevents their propagation to data products. A key aspect of this analysis involves accurately estimating the parameters of the SeaWinds transmissions. As better parameter estimates are researched and developed, the …

Nonlinear Dynamic Analysis Of An Orthotropic Composite Rotor Blade, Ming-Hung Hsu

Journal of Marine Science and Technology–Taiwan

This work presents the nonlinear dynamic analysis of orthotropic composite rotor blade using differential quadrature method (DQM). It can be found that the same efficient and procedure of DQM for both uniform composite beam and pre-twisted non-uniform composite beam. In this approach, only nine sample points are needed to achieve convergence. Dynamic responses of orthotropic composite rotor blade with various rotor rotation speeds are determined. Both linear and nonlinear dynamic responses have been obtained in order to study the significance of the nonlinear effect. The transient responses of the derived systems are calculated by using Newmark method. The bending-torsion coupled …

Single And Multiple Surface Scatterings From Rough Surfaces, Chin-Yuan Hsieh, Shun-Hsyung Chang

Journal of Marine Science and Technology–Taiwan

The objective of this paper is to study the contributions of multiple scattering and compare it with those of the single scattering from randomly rough surfaces. The existing Kirchhoff, small perturbation and IEM scattering model cannot be used to predict the multiple scattering along the azimuth angle. In this paper we modify the IEM model by adding the phase terms in Green’s function and its derivative for multiple scattering. The function of phase term is significant to investigate the contribution of multiple scattering in the upward and downward directions. The contribution by multiple scattering is mainly based on the normalized …

An Examination Into The Statistics Of The Singular Vectors For The Multi-User Mimo Wireless Channel, Scott Nathan Gunyan

Theses and Dissertations

Many capacity and near-capacity achieving methods in multiple-input-multipleoutput (MIMO) wireless channels make use of the singular value decomposition (SVD) of the channel matrix. For the multi-user case, the SVD of the channel matrix for each user may result in right and left singular vectors that are similar between users. This proposes another descriptive characterization of the multi-user MIMO channel. Closely aligned singular vectors between any two users could reduce the achievable signaling rates of signal processing communication methods as one user would be more difficult to resolve in space-time from another. An examination into how this alignment can be described …

Electromagnetic Interference Of System On Package, Toshio Sudo, Hideki Sasaki, Norio Masuda, James L. Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

Electromagnetic interference (EMI) issues are expected to be crucial for next-generation system-on-package (SOP) integrated high-performance digital LSIs and for radio frequency (RF) and analog circuits. Ordinarily in SOPs, high-performance digital LSIs are sources of EMI, while RF and analog circuits are affected by EMI (victims). This paper describes the following aspects of EMI in SOPs: 1) die/package-level EMI; 2) substrate-level EMI; 3) electromagnetic modeling and simulation; and 4) near electromagnetic field measurement. First, LSI designs are discussed with regard to radiated emission. The signal-return path loop and switching current in the power/ground line are inherent sources of EMI. The EMI …

Imaging Techniques And Hardware For Inhomogeneous Mri, David A. Thayer

Theses and Dissertations

Magnetic Resonance Imaging (MRI) has become one of the most important medical imaging modalities over the past few decades because of its flexibility and low risk, along with other useful attributes. For traditional MRI, the static magnetic field, B_0, must be highly homogeneous. Obtaining this homogeneity can be difficult. Traditional MRI also requires linear gradient fields that are directed along the static field direction. Under these conditions a Fourier transform relationship exists between sampled data and the image to be reconstructed. In the case of an inhomogeneous static field, gradient fields that are not linear, or gradients that are not …