Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network™

Open Access. Powered by Scholars. Published by Universities.®

Electrical and Computer Engineering

Institution
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 13261 - 13290 of 14323

Full-Text Articles in Entire DC Network

Computation Of Stable Invariant Subspaces Of Hamiltonian Matrices, R. V. Patel, Z. Lin, Pradeep Misra Jan 1994

Computation Of Stable Invariant Subspaces Of Hamiltonian Matrices, R. V. Patel, Z. Lin, Pradeep Misra

Electrical Engineering Faculty Publications

This paper addresses some numerical issues that arise in computing a basis for the stable invariant subspace of a Hamiltonian matrix. Such a basis is required in solving the algebraic Riccati equation using the well-known method due to Laub. Two algorithms based on certain properties of Hamiltonian matrices are proposed as viable alternatives to the conventional approach.

Go to article

Polarimetric Fiber Optic Weigh-In-Motion Sensor, Jieping Wang Jan 1994

Polarimetric Fiber Optic Weigh-In-Motion Sensor, Jieping Wang

Theses

During the past decade, the demand for new methods of measuring the weight of moving vehicles has grown substantially. In the 1980's, several techniques for weighing vehicles in motion were developed. However, they often suffer from high installation and maintenance costs as well as low accuracy. This thesis describes a new technique based on polarization preserving optical fibers. A fibercore HB600 Bow-Tie fiber with an initial beat length of 1.16 mm was employed in the present study. Sensor response is discussed in terms of the effects of force amplitudes and velocities on the calibration parameter Tf. Tf …

Go to article

Numerical Modeling Of Cuinse2 An D Cdte Solar Cells, Jeffery L. Gray, Richard. J. Schwartz, Youn Jung Lee Jan 1994

Numerical Modeling Of Cuinse2 An D Cdte Solar Cells, Jeffery L. Gray, Richard. J. Schwartz, Youn Jung Lee

Department of Electrical and Computer Engineering Technical Reports

No abstract provided.

Go to article

Effective Bandgap Shrinkage In Gaas, E. S. Harmon, Michael R. Melloch, Mark S. Lundstrom Jan 1994

Effective Bandgap Shrinkage In Gaas, E. S. Harmon, Michael R. Melloch, Mark S. Lundstrom

Department of Electrical and Computer Engineering Faculty Publications

Electrical measurements of the equilibrium np product (n2ie) in heavily doped n‐ and p‐GaAs were performed. The n2ieDproduct (where D is the diffusivity) was measured by fitting the collector current‐voltage characteristic of a homojunction bipolar transistor to an ideal diode equation modified to account for transport in thin base transistors.The n2ie product was then extracted from n2ieD by utilizing diffusivity results obtained with the zero‐field time‐of‐flight technique. Our results show significant effective band‐gap shrinkage in heavily doped p‐GaAs, and very little effective band‐gap shrinkage …

Go to article

A Study Of Dc Permanent Magnet Motor Noise Related To Line Current, Candace Rogers Suriano Jan 1994

A Study Of Dc Permanent Magnet Motor Noise Related To Line Current, Candace Rogers Suriano

Department of Electrical and Computer Engineering Technical Reports

Lightweight, compact and inexpensive DC permanent magnet motors are well suited for low cost high production use in industry. Unfortunately, the audible noise emanating from these motors can cause a false negative perception of the motor's quality. In cars, for example, fan motor noise can be a nuisance. The objective of this thesis is to examine the connection between motor noise and the line current wave form for a specific four pole DC permanent magnet motor. It is further concerned with identifying the underlying factors which influence the line current ripple. An audible noise to motor current transfer function is …

Go to article

Investigation Of Cebus Traffic Across A Router, With And Without Acknowledgment, Wannakuwattawaduge Lalith Fernando Jan 1994

Investigation Of Cebus Traffic Across A Router, With And Without Acknowledgment, Wannakuwattawaduge Lalith Fernando

Theses

A power line and twisted pair implementation of the Consumer Electronic Bus(CEBus) has great potential toward inexpensive home automation. Since the introduction of the CEBus Standard, there has been increasing efforts on evaluating its performance. However, most of the work has been performed for unacknowledged networks. Pan[18] was able to implement an acknowledged network for PL CEBus. In this thesis, the acknowledgment process has been taken one step further. The effect of acknowledgment on a Power Line and Twisted Pair CEBus network interconnected by a router is studied. CEBus network performance parameters such as message and packet delays, message throughput, …

Go to article

The Characteristics Of Motion And Time Study In Taiwan's Electronics Industry And Their Relationship To Business Size, Betty Chang Jan 1994

The Characteristics Of Motion And Time Study In Taiwan's Electronics Industry And Their Relationship To Business Size, Betty Chang

Dissertations and Theses @ UNI

This research was conducted to investigate the characteristics of motion and time study implementation in Taiwan's electronics industry, as perceived by industrial engineers, and the relationships of these perceptions to business sizes of the firms. The questionnaires were mailed to 252 industrial engineers in the general firms group. A total of 206 (81.75%) instruments were returned. The questionnaires were then mailed to another 15 industrial engineers in the highly productive firms group. All the instruments (100%) were returned from the highly productive firm group. Telephone interviews were later conducted with six selected highly productive electronics firms to investigate their successful …

Go to article

Optimal Control Of Infinite-Order Smart Composite Structural Systems Using Distributed Sensors, Robert Butler, Vittal S. Rao Jan 1994

Optimal Control Of Infinite-Order Smart Composite Structural Systems Using Distributed Sensors, Robert Butler, Vittal S. Rao

Electrical and Computer Engineering Faculty Research & Creative Works

In recent years there has been considerable interest in the design of spatially shaped distributed sensors for the control of infinite-order structural systems. The smart materials polyvinylidene fluoride (PVDF) and shape-memory alloys can be utilized in the development of customized distributed sensors. Sensor shape-optimization techniques are needed for the implementation of optimal control strategies. In this paper, a method for generating the shapes of distributed sensors using finite-dimensional approximations to desired curvature and curvature rate kernels is examined. The output of these spatially distributed sensors is utilized directly as the control signal for suppressing vibrations in infinite-order structural systems. This …

Go to article

The Adaptive Control Of Smart Structures Using Neural Networks, Vittal Rao, Rajendra Damle, Chris Tebbe, Frank J. Kern Jan 1994

The Adaptive Control Of Smart Structures Using Neural Networks, Vittal Rao, Rajendra Damle, Chris Tebbe, Frank J. Kern

Electrical and Computer Engineering Faculty Research & Creative Works

The application of adaptive control algorithms for vibration suppression of smart structures is investigated in this paper. An accurate mathematical representation is not required in this approach. The controller adapts to the parameter variations of the structural system by updating the controller gains. When the desired performance of an unknown plant with respect to an input signal can be specified in the form of a linear or a non-linear differential equation, stable control can be achieved using model-reference adaptive control (MRAC) techniques. The conventional MRAC techniques have been successfully implemented on a smart-structure test article resulting in perfect model following. …

Go to article

Voltage Collapse. An Engineering Challenge, Mariesa Crow, Bernard C. Lesieutre Jan 1994

Voltage Collapse. An Engineering Challenge, Mariesa Crow, Bernard C. Lesieutre

Electrical and Computer Engineering Faculty Research & Creative Works

Voltage collapse is characterised by a loss of control of the voltage levels in a power system. Although all of the precise mechanisms that affect voltage collapse have not yet been identified, voltage instabilities are known to occur when the power system is operating under a stressed state. The authors discuss voltage collapse and its relationship with the point of maximum power transfer and how voltage collapse can be better predicted

Go to article

Neural Network Enhancement Of The Los Alamos Force Deployment Estimator, Bobby Turner, Donald C. Wunsch Jan 1994

Neural Network Enhancement Of The Los Alamos Force Deployment Estimator, Bobby Turner, Donald C. Wunsch

Electrical and Computer Engineering Faculty Research & Creative Works

The Force Deployment Estimator (FDE) is a decision support system. It allocates transportation resources given inputs such as forces to be deployed and their desired arrival times. Other inputs are assumptions about conditions that affect performance: carrier start time, node capacity, sustainment shipping time, bulk sustainment per day, ammo sustainment per day, unit start time, carrier service time, carrier round trip time, and carrier reassignment time. Outputs include the mean and standard deviation of estimated unit arrival times versus goal times, and data files for post-processing. However, when a goal time is not met, the simulator gives no explanation of …

Go to article

Model Parameter And Time Delay Estimation Using Gradient Methods, Aidan O'Dwyer, John Ringwood Jan 1994

Model Parameter And Time Delay Estimation Using Gradient Methods, Aidan O'Dwyer, John Ringwood

Conference papers

A number of approaches have been proposed for parameter and time delay estimation of process models in single input, single output (SISO) control systems using gradient descent algorithms; some of these approaches involve the selection of a rational polynomial that is used to approximate time delay variations. This paper takes a generalised approach to the investigation of the most appropriate choice of the rational polynomial, and the gradient descent algorithm, to be used.

Go to article

Neural Network Diagnosis Of Malignant Melanoma From Color Images, Fikret Erçal, Hsi-Chieh Lee, William V. Stoecker, Randy Hays Moss, Anurag Chawla Jan 1994

Neural Network Diagnosis Of Malignant Melanoma From Color Images, Fikret Erçal, Hsi-Chieh Lee, William V. Stoecker, Randy Hays Moss, Anurag Chawla

Computer Science Faculty Research & Creative Works

Malignant melanoma is the deadliest form of all skin cancers. Approximately 32,000 new cases of malignant melanoma were diagnosed in 1991 in the United States, with approximately 80% of patients expected to survive 5 years. Fortunately, if detected early, even malignant melanoma may be treated successfully, Thus, in recent years, there has been rising interest in the automated detection and diagnosis of skin cancer, particularly malignant melanoma. Here, the authors present a novel neural network approach for the automated separation of melanoma from 3 benign categories of tumors which exhibit melanoma-like characteristics. The approach uses discriminant features, based on tumor …

Go to article

Microwave Diagnosis Of Rubber Compounds, Stoyan I. Ganchev, J. Bhattacharyya, Sasan Bakhtiari, Nasser N. Qaddoumi, Deborah Brandenburg, R. Zoughi Jan 1994

Microwave Diagnosis Of Rubber Compounds, Stoyan I. Ganchev, J. Bhattacharyya, Sasan Bakhtiari, Nasser N. Qaddoumi, Deborah Brandenburg, R. Zoughi

Electrical and Computer Engineering Faculty Research & Creative Works

The results of a study investigating the dielectric properties of rubber compounds and their constituents in the frequency range of 5 to 24 GHz are presented. A completely filled short circuited waveguide technique was used to conduct these dielectric measurements. The influence of carbon black content in rubber was investigated for carefully prepared rubber samples. The results showed that for all frequencies, the dielectric constant increases as a function of increasing carbon black content. The variation of dielectric constant values decreases as frequency increases. The presence of curatives in uncured rubber samples was also detected, which indicates the sensitivity of …

Go to article

On Fault Modeling And Testing Of Content-Addressable Memories, Waleed K. Al-Assadi, A. P. Jayasumana, Y. K. Malaiya Jan 1994

On Fault Modeling And Testing Of Content-Addressable Memories, Waleed K. Al-Assadi, A. P. Jayasumana, Y. K. Malaiya

Electrical and Computer Engineering Faculty Research & Creative Works

Associative or content addressable memories can be used for many computing applications. This paper discusses fault modeling for the content addressable memory (CAM) chips. Detailed examination of a single CAM cell is presented. A functional fault model for a CAM architecture executing exact match derived from the single cell model is presented. An efficient testing strategy can be derived using the proposed fault model

Go to article

Automation Of Formation Flight Control, Vincent P. Reyna Jan 1994

Automation Of Formation Flight Control, Vincent P. Reyna

Theses and Dissertations

The research contained in this thesis explores the concepts of Automated Formation Flight Control documented in three previous AFIT theses. The generic formation analyzed consists of a Leader and Wingman, with the Wingman referencing its maneuvers off of Leader maneuvers. Specifically, planar formation flight control concerning only heading and velocity changes is considered. Next, the vertical separation constraint is relaxed to allow wing maneuvers outside of the flight plane of the lead in order to minimize the energy expended by the wing in a maneuver. Analysis of the two forms of formation flight control investigated in this thesis reveals the …

Go to article

Optical Wavelet Transform For Fingerprint Identification, Robert P. Macdonald Dec 1993

Optical Wavelet Transform For Fingerprint Identification, Robert P. Macdonald

Theses and Dissertations

The Federal Bureau of Investigation FBI has recently sanctioned a wavelet fingerprint image compression algorithm developed for reducing storage requirements of digitized fingerprints. This research implements an optical wavelet transform of a fingerprint image, as the first step in an optical fingerprint identification process. Wavelet filters are created from computer generated holograms of biorthogonal wavelets, the same wavelets implemented in the FBI algorithm. Using a detour phase holographic technique, a complex binary filter mask is created with both symmetry and linear phase. The wavelet transform is implemented with continuous shift using an optical correlation between binarized fingerprints written on a …

Go to article

Human Visual System Enhancement Of Reconstructed Satellite Images, James E. Treleaven Dec 1993

Human Visual System Enhancement Of Reconstructed Satellite Images, James E. Treleaven

Theses and Dissertations

This research investigated the enhancement of satellite images. The goal was to develop and test a suite of image enhancement software routines to improve the quality of reconstructed images for the human visual system. The primary focus was to enhance satellite features. Enhancement was accomplished in both the spatial domain and the frequency domain. In the spatial domain, routines were developed to enhance image contrast and edges. In the frequency domain, a routine was developed using research into the human visual system. The transfer function of the human visual system was used to develop a filter for frequency domain enhancement. …

Go to article

Radar Cross Section Visualization Using Sample Buffer Progressive Refinement Volume Rendering, Alain L. Jones Dec 1993

Radar Cross Section Visualization Using Sample Buffer Progressive Refinement Volume Rendering, Alain L. Jones

Theses and Dissertations

This study developed a prototype for an interactive radar cross section visualization software system. The system, hosted on a Silicon Graphics workstation, is intended to support aircrews, mission planners, aircraft designers, and others who require an understanding of aircraft radar cross section characteristics. The input to the system is a set of radar cross section samples taken at various aspect angles. A pre-processor developed as part of this study transforms the input radar cross section data into a three-dimensional cuberille data volume. This data volume is then visualized using an interactive volume renderer. The interactive volume renderer implements progressive image …

Go to article

Enhanced Tracking Of Airborne Targets Using Forward Looking Infrared And Laser Return Measurements, Patrick J. Grondin Dec 1993

Enhanced Tracking Of Airborne Targets Using Forward Looking Infrared And Laser Return Measurements, Patrick J. Grondin

Theses and Dissertations

The Air Force Institute of Technology has been involved in developing Kalman filter based trackers of ballistic missiles for 15 years. The goal of this thesis is to develop a Multiple Model Adaptive Estimator MMAE that tracks the missile plume using a forward looking infrared sensor and the missile hardbody center-of-mass additionally using low energy laser returns for the purpose of directing a high power laser to incapacitate the missile. The missile plume pogos about an offset equilibrium point relative to the hardbody center-of-mass with an amplitude and frequency of oscillation that are not precisely known a priori. The MMAE …

Go to article

Filtering, Coding, And Compression With Malvar Wavelets, Stephen R. Hall Dec 1993

Filtering, Coding, And Compression With Malvar Wavelets, Stephen R. Hall

Theses and Dissertations

This thesis develops and evaluates a number of new concepts and tools for the analysis of signals using Malvar wavelets lapped orthogonal transforms . Windowing, often employed as a spectral estimation technique, can result in irreparable distortions in the transformed signal. By utilizing the Malvar wavelet, any signal distortion resulting from the transformation can be eliminated or cancelled during reconstruction. This is accomplished by placing conditions on the window and the basis function and then incorporating the window into the orthonormal representation. Paradigms for both a complex-valued and a real-valued Malvar wavelet are summarized. I-lie algorithms for the wavelets were …

Go to article

Developing A Graphical User Interface To Support A Real-Time Digital Signal Processing System, Jeffrey C. Miller Dec 1993

Developing A Graphical User Interface To Support A Real-Time Digital Signal Processing System, Jeffrey C. Miller

Theses and Dissertations

A graphical software user interface for a VMEbus-based real-time digital signal processing system was designed. Use, requirements were defined and the Rumbaugh object-oriented analysis and design technique was applied to analyze the requirements and produce an object-oriented design. The software design includes a graphical, mouse- and keyboard driven user interface, specialized hardware driver modules, and operating system interfaces. An implementation plan was also developed to map the design into the C programming language using existing system code, automatically generated code, and newly written code. Based on the implementation plan, a limited software system prototype w successfully developed and demonstrated. The …

Go to article

A Concept For Sled Testing Minuteman Iii Guidance Systems, Hossny El-Sherief, Dave Knight, Daniel J. Simon, Myron Teeter Dec 1993

A Concept For Sled Testing Minuteman Iii Guidance Systems, Hossny El-Sherief, Dave Knight, Daniel J. Simon, Myron Teeter

Electrical and Computer Engineering Faculty Publications

No abstract provided.

Go to article

Analysis And Characteristics Of Compressor Stall Precursor Signals In Forward And Aft Swept High Speed Compressor, Bernard J. Frank Dec 1993

Analysis And Characteristics Of Compressor Stall Precursor Signals In Forward And Aft Swept High Speed Compressor, Bernard J. Frank

Theses and Dissertations

The stall characteristic of four single-stage transonic compressor rotors were investigated as they were throttled to stall. Forward-swept, backward-swept, and straight leading edge rotors were examined. Three methods of analysis (1) windowed power spectrum densities of pressure and spatial Fourier coefficients, (2) phase tracking analysis, and (3) system identification were used to identify the first appearance of modal waves and their accompanying frequencies in order to identify a stall warning time. A direct correlation between the amount of stall warning time and the shape of the compressor characteristic was found. Specifically, if the compressor characteristic had a significant period of …

Go to article

Exploring Qdes As A Tool For Determining Limits Of Achievable Performance In Aircraft Design, Mark F. Reidinger Dec 1993

Exploring Qdes As A Tool For Determining Limits Of Achievable Performance In Aircraft Design, Mark F. Reidinger

Theses and Dissertations

This thesis explores the usefulness of a computer aided control design software package called QDES in determining the limits of achievable aircraft performance as it relates to controller capability. Modern aircraft, particularly fighters, are being designed to be statically unstable to enhance their maneuverability and performance. It is possible that the aircraft, although physically capable of a certain level of performance due to its engine/ airframe combination, may be uncontrollable up to this level. This study sought to develop a methodology to use QDES to make a preliminary analysis of an aircraft design to determine if there exists a controller …

Go to article

Partitioning Structural Vhdl Circuits For Parallel Execution On Hypercubes, Kevin L. Kapp Dec 1993

Partitioning Structural Vhdl Circuits For Parallel Execution On Hypercubes, Kevin L. Kapp

Theses and Dissertations

Distributing simulations among multiple processors is one approach to reducing VHDL simulation time for large VLSI circuit designs. However, parallel simulation introduces the problem of how to partition the logic gates and system behaviors among the available processors in order to obtain maximum speedup. This research investigates deliberate partitioning algorithms that account for the complex inter-dependency structure of the circuit behaviors. Once an initial partition has been obtained, a border annealing algorithm is used to iteratively improve the partition. In addition, methods of measuring the cost of a partition and relating it to the resulting simulation performance are investigated. Structural …

Go to article

Weapon System Sensor Integration For A Dis-Compatible Virtual Cockpit, Matthew N. Erichsen Dec 1993

Weapon System Sensor Integration For A Dis-Compatible Virtual Cockpit, Matthew N. Erichsen

Theses and Dissertations

This thesis continues the Virtual Cockpit VC research which investigates distributed interactive virtual flying, environments. The VC vl.0 used the SIMNET protocols to only communicate position and orientation over a common network. A simple cockpit instrumentation configuration and limited head- tip display, HUD showed aircraft state. With VC vl.0 weapons or sensors could not interact in the simulation environment. The VC v2.0 transitions from the SIMNET protocol to a partial implementation of the Distributed Interactive Simulation DIS v2.0.3 protocol. Simulated radar and forward looking infra-red FLIR sensors were developed to aid operator detection and designation when employing various munition types. …

Go to article

Analysis And Simulation Of A Gps Receiver Design Using Combined Delay-Lock And Modified Tanlock Loops, George D. Harris Dec 1993

Analysis And Simulation Of A Gps Receiver Design Using Combined Delay-Lock And Modified Tanlock Loops, George D. Harris

Theses and Dissertations

The purpose of this thesis was to investigate the performance of two types of tracking loops used in Global Positioning System (GPS) receivers. The first loop, the Delay-Lock Loop (DLL), is responsible for maintaining synchronization with the received PN sequence. The second loop, the Modified Tanlock Loop (MTLL), is responsible for maintaining synchronization with the carrier signal. The performance of the two loops is investigated first separately then their performance is evaluated when operated together. This thesis is an investigation on the ability of these two loops to overcome corruption of the input signal due to noise. Expanding the dynamic …

Go to article

Design Of A Flight Controller For An Unmanned Research Vehicle With Control Surface Failures Using Quantitative Feedback Theory, Mark S. Keating Dec 1993

Design Of A Flight Controller For An Unmanned Research Vehicle With Control Surface Failures Using Quantitative Feedback Theory, Mark S. Keating

Theses and Dissertations

This thesis describes the application of the multiple-input multiple- output (MIMO) Quantitative Feedback Theory (QFT) design technique to the design of a digital flight control system for the Lambda Unmanned Research Vehicle (URV). The QFT technique allows the synthesis of a control system which is robust in the presence of structured plant uncertainties. Uncertainties considered in this design are the aircraft's plant variation within the flight envelope and the effects of damage to aircraft control surfaces. Mathematical models of control surface failure effects on aircraft dynamics are derived and used to modify an existing small perturbation model of the Lambda. …

Go to article

Investigation Into Model-Based Fuzzy Logic Control, Michael W. Logan Dec 1993

Investigation Into Model-Based Fuzzy Logic Control, Michael W. Logan

Theses and Dissertations

This thesis investigates the feasibility of a proposed hybrid linear/Fuzzy controller for nonlinear plants. The proposed controller concept is based on the use of multiple linearizations of a nonlinear plant, which describe the dynamics of perturbations about equilibrium points throughout the desired envelope of operation. A bank of linear compensators is developed, each corresponding to a linearized plant about a different equilibrium. The multiple control signals generated by the bank of compensators are then weighted and summed using Fuzzy Logic to produce a composite control perturbation signal, which is used to drive the nonlinear plant. Experiments were conducted to test …

Go to article

First Prev Next Last