Engineering Commons^™

Development Of An Efficient Ti:Sapphire Laser Transmitter For Atmospheric Ozone Lidar Measurements, Khaled A. Elsayed

Electrical & Computer Engineering Theses & Dissertations

The impetus of this work was to develop an all solid-state Ti:sapphire laser transmitter to replace the current dye lasers that could provide a potentially compact, robust, and highly reliable laser transmitter for differential absorption lidar measurements of atmospheric ozone. Two compact, high-energy pulsed, and injection-seeded Ti:sapphire lasers operating at a pulse repetition frequency of 30 Hz and wavelengths of 867 nm and 900 nm, with M² of 1.3, have been experimentally demonstrated and compared to model results. The Ti:sapphire lasers have shown the required output beam quality at maximum output pulse energy, 115 mJ at 867 nm and …

Eye Pattern Evaluation In High-Speed Digital Systems Analysis By Using Mtl Modeling, Giulio Antonini, James L. Drewniak, Antonio Orlandi, Vittorio Ricchiuti

Electrical and Computer Engineering Faculty Research & Creative Works

A method for simulating the eye pattern of high-speed digital signals propagated on printed circuit boards using multiconductor transmission-line modeling is proposed in this paper. The approach takes into account the frequency-dependent properties of the dielectric materials of the board and of the conductors. The validation is performed by comparing the modeling with measurements taken from the literature, and directly performed on test boards specially design for this study.

Semiconducting Polymer Leds, David Braun

Electrical Engineering

Technologies based on organic semiconductors may answer the increasing demands that consumers make in the areas of large-area electronics, lightweight displays, and portable computing. Advances in scientific understanding, technology, and device performance have occurred particularly rapidly in the area of polymer light-emitting diodes (LEDs). Material properties and economic considerations suggest that polymer LEDs are the devices most likely to win the race to applications that produce light on inorganic substrates such as glass and silicon, as well as plastic substrates.
The field of semiconducting polymers has its root in the 1977 discovery of the semiconducting properties of polyacetylene¹. …

Analysis On Possible Solution To Decreasing The Effect Of Non-Uniform Air-Gaps Due To Rotor Eccentricity In Asynchronous Machines, Dominic Chambega

Tanzania Journal of Engineering and Technology (TJET)

Rotor eccentricity introduces non-uniformity of the airgap which in turn causes additional frictional torques and losses in addition to establishing a uni-directional pulling magnetic force which is disastrous to the machine. This paper analyses the extent of the damage to the machine due to non-uniformity of the air-gap and proposes increasing the number of poles as a possible solution to arrest the effect. It is found through the analysis that as the number of poles increases the effect of eccentricity decreases.

A Comparative Application Of Telecommunication Traffic Forecasting Methods To A Backbone Link In Tanzania, M. L. Luhanga

Tanzania Journal of Engineering and Technology (TJET)

In this paper various mathematical models to characterize and forecast telecommunication traffic time series traffic have been applied, and the ranges of validity of the models are determined by comparing them with measured traffic data using the measurement errors criteria method which resulted into the superior model. Based on this model the ARIMA (0,2,1) model for smoothed data, the traffic forecast findings show that by the year 2006, the traffic demand will exceed the current installed capacity of 140 Mbps in the Tanzania Telecommunications Company Limited (TTCL) network along the major link between the Dar es Salaam and Dodoma backbone …

Probabilistic Microcell Prediction Model, Song-Kyoo Kim

Electrical Engineering and Computer Science Faculty Publications

A microcell is a cell with 1-km or less radius which is suitable for heavily urbanized area such as a metropolitan city. This paper deals with the microcell prediction model of propagation loss which uses probabilistic techniques. The RSL (Receive Signal Level) is the factor which can evaluate the performance of a microcell and the LOS (Line-Of-Sight) component and the blockage loss directly effect on the RSL. We are combining the probabilistic method to get these performance factors. The mathematical methods include the CLT (Central Limit Theorem) and the SPC (Statistical Process Control) to get the parameters of the distribution. …

Fast Landmark-Based Registration Via Deterministic And Efficient Processing, Some Preliminary Results, Fred W. Depiero

Electrical Engineering

Preliminary results of a new method for range view registration are presented. The method incorporates the LeRP Algorithm, which is a deterministic means to approximate subgraph isomorphisms. Graphs are formed that describe salient scene features. Graph matching then provides the scene-to-scene correspondence necessary for registration. A graphical representation is invariant with respect to sensor standoff. Test results from real and synthetic images indicate that a reasonable tradeoff between speed and accuracy is achievable. A mean rotational error of ~1 degree was found for a variety of test cases. Mean compute times were found to be better than 2 Hz, with …

Autoassociative-Heteroassociative Neural Network, Claudia V. Kropas-Hughes, Steven K. Rogers, Mark E. Oxley, Matthew Kabrisky

AFIT Patents

An efficient neural network computing technique capable of synthesizing two sets of output signal data from a single input signal data set. The method and device of the invention involves a unique integration of autoassociative and heteroassociative neural network mappings, the autoassociative neural network mapping enabling a quality metric for assessing the generalization or prediction accuracy of the heteroassociative neural network mapping.

Turing Day : 90Ème Anniversaire De La Naissance De Alan Mathison Turing, Christof Teuscher

Electrical and Computer Engineering Faculty Publications and Presentations

A brief statement on the life work and significance of computing pioneer Alan Turing, on the 90th anniversary of his birth.

A Course Assessment Of The Microelectronics Process Engineering Program At Sjsu, Gregory Young, Stacy H. Gleixner, David W. Parent, Yasser Dessouky, Emily Allen, Linda Vanasupa

Faculty Publications

The program assessment strategy of San Jose State University's new interdisciplinary curriculum in Microelectronics Process Engineering is described. Vertical integration of specific class and program learning objectives allows for a clear and efficient method to evaluate the continued growth and improvement of the program. The program assessment process relies on clearly defined and detailed program and course learning objectives that are linked vertically to ABET outcomes. In addition, we discuss briefly the structure of the program and the "hands-on" experience that we provide the students.

Nonresonant Detection Of Terahertz Radiation In Field Effect Transistors, W. Knap, V. Kachorovskii, Y. Deng, S. Rumyantsev, J.-Q. Lü, R. Gaska, M. S. Shur, Grigory Simin, X. Hu, M. Asif Khan, C. A. Saylor, L. C. Brunel

Faculty Publications

We present an experimental and theoretical study of nonresonant detection of subterahertz radiation in GaAs/AlGaAs and GaN/AlGaN heterostructurefield effect transistors. The experiments were performed in a wide range of temperatures (8–300 K) and for frequencies ranging from 100 to 600 GHz. The photoresponse measured as a function of the gate voltage exhibited a maximum near the threshold voltage. The results were interpreted using a theoretical model that shows that the maximum in photoresponse can be explained by the combined effect of exponential decrease of the electron density and the gate leakage current.

Airborne Radar Interference Suppression Using Adaptive Three-Dimensional Techniques, Todd B. Hale

Theses and Dissertations

This research advances adaptive interference suppression techniques for airborne radar, addressing the problem of target detection within severe interference environments characterized by high ground clutter levels, levels, noise jammer infiltration, and strong discrete interferers. Two-dimensional (2D) Space-Time Adaptive Processing (STAP) concepts are extended into three-dimensions (3D) by casting each major 2D STAP research area into a 3D framework. The work first develops an appropriate 3D data model with provisions for range ambiguous clutter returns. Adaptive 3D development begins with two factored approaches, 3D Factored Time-Space (3D-FTS) and Elevation-Joint Domain Localized (Elev-JDL). The 3D adaptive development continues with optimal techniques, i.e., …

Dynamic Multiphysics Model For Solar Array, Shengyi Liu, Roger A. Dougal

Faculty Publications

An approach to model the solar cell system with coupled multiphysics equations (photovoltaic, electro-thermal, direct heating and cooling processes) within the context of the resistive-companion method in the Virtual Test Bed computational environment is presented. Appropriate across and through variables are defined for the thermal terminal of the system so that temperature is properly represented as a state variable, rather than as a parameter of the system. This allows enforcement of the system power conservation through all terminals, and allows simultaneous solutions for both the electrical potentials and the system temperature. The thermal port built accordingly can be used for …

A Simplistic Plasma Dust Removal Model Employing Radiation Pressure, Robert A. Schill Jr.

Electrical & Computer Engineering Faculty Research

A simple heuristic model is developed to examine the feasibility of using radiation pressure as a means to transport plasma dust out of the path of the forthcoming electron or photon beam. A slow electromagnetic surface wave coupled to a planar target or substrate exerts the required pressure in the removal process. The model is examined using data and parameters from single-shot radiography experiments. Optimal source requirements are identified for a typical radiography experiment. Source energies and powers are a minimum over an optimum band of frequencies where both conduction and plasma oscillation effects are mutually significant. Above the band …

Implementation Of Large Neural Networks Using Decomposition, Henry Selvaraj, H. Niewiadomski, P. Buciak, M. Pleban, Piotr Sapiecha, Tadeusz Luba, Venkatesan Muthukumar

Electrical & Computer Engineering Faculty Research

The article presents methods of dealing with huge data in the domain of neural networks. The decomposition of neural networks is introduced and its efficiency is proved by the authors’ experiments. The examinations of the effectiveness of argument reduction in the above filed, are presented. Authors indicate, that decomposition is capable of reducing the size and the complexity of the learned data, and thus it makes the learning process faster or, while dealing with large data, possible. According to the authors experiments, in some cases, argument reduction, makes the learning process harder.

Cuin1-Xalxse2 Thin Films And Solar Cells, P. D. Paulson, M. W. Haimbodi, S. Marsillac, R. W. Birkmire, W. N. Shafarman

Electrical & Computer Engineering Faculty Publications

CuIn[sub 1-x]Al[sub x]Se[sub 2] thin films are investigated for their application as the absorber layer material for high efficiency solar cells. Single-phase CuIn[sub 1-x]Al[sub x]Se[sub 2] films were deposited by four source elemental evaporation with a composition range of 0≤x≤0.6. All these films demonstrate a normalized subband gap transmission >85% with 2 µm film thickness. Band gaps obtained from spectroscopic ellipsometry show an increase with the Al content in the CuIn[sub 1-x]Al[sub x]Se[sub 2] film with a bowing parameter of 0.62. The structural properties investigated using x-ray diffraction measurements show a decrease in lattice spacing as the Al content increases. …

Validation Of Sea Ice Motion From Quikscat With Those From Ssm/I And Buoy, David G. Long, Yunhe Zhao, Antony K. Liu

Faculty Publications

Arctic sea ice motion for the period from October 1999 to March 2000 derived from QuikSCAT and ocean buoy observations. Special Sensor Microwave/Imager (SSM/I) data using the wavelet analysis method agrees well with ocean buoy observations. Results from QuikSCAT and SSM/I are compatible when compared with buoy observations and complement each other. Sea ice drift merged from daily results from QuikSCAT, SSM/I, and buoy data gives more complete coverage of sea ice motion. Based on observations of six months of sea ice motion maps, the sea ice motion maps in the Arctic derived from QuikSCAT data appear to have smoother …

Closed Loop Identification Of A First Order Plus Dead Time Process Model Under Pi Control, Tony Kealy, Aidan O'Dwyer

Conference papers

Abstract -- This paper discusses the estimation of the parameters of a first order plus dead-time process model using the closed-loop step response data of the process under proportional plus integral (PI) control. The proportional gain and the integral time, in the PI controller, are chosen such that the closed-loop step response exhibits an under-damped response. From this response data, five characteristic points are used to determine a second order plus dead-time model and subsequently, the frequency response of the closed-loop system. Knowing the dynamics of the closed-loop system and the dynamics of the controller, the open-loop dynamics of the …

Adaptive Predictive Congestion Control Of High-Speed Atm Networks, Sarangapani Jagannathan, Jayasree Talluri

Electrical and Computer Engineering Faculty Research & Creative Works

This paper proposes an auto regressive moving average (ARMAX)-based adaptive control methodology to prevent congestion in high-speed asynchronous transfer mode (ATM) networks. Adaptive controller is developed to control traffic where sources adjust their transmission rates in response to the feedback information from the network switches. Specifically, the buffer dynamics at a given switch is modeled as a nonlinear discrete-time system and an ARMAX controller is designed so as to predict the explicit values of the transmission rates of the sources so as to prevent congestion. Tuning methods are provided for the unknown coefficients of the ARMAX model to estimate the …

Logic Synthesis Of Reversible Wave Cascades, Alan Mishchenko, Marek Perkowski

Electrical and Computer Engineering Faculty Publications and Presentations

A circuit is reversible if it maps each input vector into a unique output vector, and vice versa. Reversible circuits lead to power-efficient CMOS implementations. Reversible logic synthesis may be applicable to optical and quantum computing. Minimizing garbage bits is the main challenge in reversible logic synthesis. This paper introduces an algorithm to generate the cascade of reversible complex Maitra terms (called here reversible wave cascade) implementing incompletely specified Boolean functions. The remarkable property of the presented method compared to other reversible synthesis methods is that it creates at most one constant input and no additional garbage outputs. Preliminary estimation …

Theory And Design Of Mixed Lumped-Distributed Cross-Coupled Filters With Applications To Linear Phase Shifter And Tunable Filters, Sanghoon Shin

Dissertations

Using cross-coupled networks of a new concept, transmission zeros were efficiently located in the complex frequency-domain. With this approach, the group delay and attenuation slope of the circuit network can be controlled to get both sharp rejection characteristics and linear phase slopes. In order to achieve this performance, various types of combline filters are suggested. Various simulation tools (commercial linear circuit and E-M simulators), as well as the developed pole-zero locator program, were used to design a new class of cross-coupled networks. In particular, the polezero locator program can be used to extract an equivalent circuit of the topology that …

Experimental Studies Of Wave Propagation In Three-Dimensional Photonic Crystals, John M. Tobias

Dissertations

Photonic crystals were proposed fifteen years ago. Propagation is selectively prevented through these crystals resulting in a photonic band gap, that is, a frequency region where light cannot propagate. These frequency bands are analogous to electronic band gaps in solid-state crystals.

The optical properties of the photonic crystal in regions near the band gap remain relatively unexplored. Yet, there is significant evidence to suggest that this avenue of investigation can provide useful optical and microwave applications. Numerical studies have predicted that the effective permittivity near the photonic band gap approaches zero and becomes negative. Selfcollimation of the propagating beam and …

Stereo Matching Algorithm By Propagation Of Correspondences And Stereo Vision Instrumentation, Peerajak Witoonchart

Theses

A new image processing method is described for measuring the 3-D coordinates of a complex, biological surface. One of the problems in stereo vision is known as the accuracy-precision tradeoff problem. This thesis proposes a new method that promises to solve this problem. To do so, two issues are addressed. First, stereo vision instrumentation methods are described. This instrumentation includes a camera system as well as camera calibration, rectification, matching and triangulation. Second, the approach employs an array of cameras that allow accurate computation of the depth map of a surface by propagation of correspondences through pair-wise camera views.

The …

Recent Advances In Silicon Light Emitting Diodes, Aravind Balakrishnan

Theses

A silicon based light emitting diode (LED) is a new gateway for combining optoelectronics with CMOS integrated circuits. The choice of silicon is limited due to its indirect band gap nature. There are new approaches for improving emission efficiencies in Si-LED to nearly 1% at room temperature. Boron implantation has been employed to introduce dislocation array and as a p-type dopant to form p-n Junction in an n-type Si substrate. The device operates as a conventional LED under forward bias. The temperature dependence of radiative recombination rate is addressed by Varshni empirical formula. The difference between the energy at which …

Determination Of Phase Composition Of Sputtered Tantalum On Steel Substrates By Resistivity Measurements, Younes Abbassi

Theses

The objective of this thesis was to develop a method of distinguishing between alpha and beta phases of tantalum films on steel substrates, using the four-point probe resistivity measurements. While there is a large difference between resistivities of the two Ta phases, the problem is challenging because the measurements are influenced by the low resistivity of steel.

For reference, the resistivity measurements of tantalum coatings (1-20 μm) on silicon and silicon dioxide substrates were conducted first. The measured resistivities were related to the crystallographic phase composition of Ta, which has lower resistivity in bcc form, α-phase, (13.5 to 42 μΩcm), …

Syntheses And Photoluminescence Of Zinc Oxide Polyaniline Coaxial Nanowires And Their Array, Zhi-Xin Zheng, Yan-Yan Xi, Ping Dong, Huai-Guo Huang, Jian-Zhang Zhou, Lin-Lin Wu, Zhong-Hua Lin

Journal of Electrochemistry

A novel nanomaterial, zinc oxide (ZnO) and polyaniline (PANI) coaxial nanowires and their array in the template, was synthesized using anodic aluminum oxide (AAO) membrane as template. The morphology of these coaxial nanowires was observed with transmission electron microscope (TEM). The experiments on photoluminescence (PL) of coaxial nanowires and their array in AAO membrane show that the visible emission band of ZnO shifts from 530 nm to 400 nm and the luminescence is enhanced for the coaxial nanowires array in AAO membrane,and the visible emission band shifts to a lower wavelergth (385 nm) for coatial nanowires in NaOH solution. Possible …

Electrochemical Properties Of Mixed Metal Oxide Coated Titanium Anodes In Seawater, Ting-Yong Wang, Li-Kun Xu, Guang-Zhang Chen

Journal of Electrochemistry

Mixed metal oxide coated titanium anodes prepared by thermal decomposition were characterized by scanning electron microscopy and electrochemical measurement, while the consumption rate of an anode was also measured in seawater. In order to examine the practical performances of mixed metal oxide-coated anodes, a simulating test on floating dock in seawater has also been carried out. The SEM results indicate that oxide layers exhibited a cracked-mud morphology which endows the anode with good electrocatalytic activity. The electrochemical measurements showed that mixed metal oxide-coated anodes exhibit excellent electrochemical activity and electrochemical stability in seawater. Owing to good corrosion resistance and low …

Corrosive Electrochemical Behavior Of Carbon Steel In Microbiological Medium, Jing Liu, Hong-Bo Fan, Hai-Ping Xu, Jia-Shen Zheng, Li-Ming Xu, Zong-Qiang Mao

Journal of Electrochemistry

Sulfate-reducing bacteria (SRB)grows and propagates, PH of the solution is dropped from 7.5 to 5.8, and forms the biofilms on carbon steel in culture medium. The micro-environment on the surface of carbon steel is changed under the biofilms, the factors accelerate the formation of the pitting corrosion. When the biofilm on carbon steel is cleaned out, the surface of carbon steel have the non-uniform pitting corrosion. The activity of SRB and the porous structure of biofilms induced the initiation and development of the pitting corrosion of carbon steel. The process of microbiologically induced corrosion (MIC) involves the development of SRB …

Recent Developments In The Electrolyte For Lic6/Electrolyte/Cathode Battery, Cui-Ying Wang, Sheng-Liang Zhao, Guang-Ming Zhu, Jin-Kua You, Zu-Geng Lin

Journal of Electrochemistry

We present a reviewed the development and status of electrolyte for LiC 6/electrolyte/cathode battery. The effect of the salt, solvent, additive and impurity on the conductivity of the electrolyte, formation of the solid-electrolyte-interphase (SEI) and cycle life of the battery were described.

A Blend Conducting Membranes For Direct Methanol Fuel Cells, Lei Li, Jun Zhang, Hong Wu, Yu-Xin Wang

Journal of Electrochemistry

An attempt was made to modify membranes for direct methanol fuel cells by blending Nafion or polystyrene sulfonic acid (PSSA) with polyvinylidene fluoride (PVDF) from their solutions. The proton conductivity and methanol barrier property as a function of the membrane compositions are discussed. Compared with the Nafion 117 membrane, the PVDF-Nafion blend membranes with 25 wt% of Nafion showed a decrease in the conductivity by about 2 orders of magnitude, and the methanol barrier properties increased about 3 orders of magnitude. If the ratio (σ/P) is adopted to characterize the performance of the membrane, the PVDF-PSSA and PVDF-Nafiion blend membranes …