Digital Commons Network^™

Numerical Solutions Of Poisson's Equation In A Superlatice Device, Norman Todd Rollins

Retrospective Theses and Dissertations

The relationship between the built-in potential and the energy bands in a heterojunction device is defined using the Anderson model. Based on this model, Poisson's equation for a nonhomogeneous semiconductor device in thermal equilibrium is derived and solved analytically for the special case of a doubly intrinsic abrupt heterojunction. Several numerical methods of solving Poisson's equation for general cases are explored to find the most efficient method. The validity of the chosen numerical method is tested against both the analytical solution for a Ge/GaAs doubly intrinsic diode and recently published results from similar numerical simulation studies. A p-i-n superlattice device …

New Directions In Subband Coding, Y. Shoham, Steven L. Grant, N. Seshadri, R. V. Cox, S. R. Quackenbush, N. S. Jayant

Electrical and Computer Engineering Faculty Research & Creative Works

Two very different subband coders are described. The first is a modified dynamic bit-allocation-subband coder (D-SBC) designed for variable rate coding situations and easily adaptable to noisy channel environments. It can operate at rates as low as 12 kb/s and still give good quality speech. The second coder is a 16-kb/s waveform coder, based on a combination of subband coding and vector quantization (VQ-SBC). The key feature of this coder is its short coding delay, which makes it suitable for real-time communication networks. The speech quality of both coders has been enhanced by adaptive postfiltering. The coders have been implemented …

Distribution Automation For The Association Of Missouri Electric Cooperatives—A Statewide Evaluation Of Load Management, Jack F. Morris, Frank J. Kern

Electrical and Computer Engineering Faculty Research & Creative Works

Presented is an in-depth technical and economic feasibility study utilizing one- and two-way management systems for statewide load control and distribution automation. Included are 1) an evaluation of the generation and transmission load patterns of the state cooperatives and the determination of the amount of controllable load for use by a load management system, 2) an in-depth economic cost-benefit study as a result of implementing a load management system on a statewide basis, 3) communication alternatives for implementing the statewide load management and distribution automation system, 4) an investigation into using an existing statewide microwave communications system for direct load …

Simulation Of Communication Systems Using Personal Computers, William H. Tranter, Carl R. Ryan

Electrical and Computer Engineering Faculty Research & Creative Works

Microcomputer simulation provides a powerful tool for computer-aided design and analysis of communication systems and requires a minimum of investment. Two different simulation examples are presented: a fixed topology simulation program for digital data links written in Pascal; and a simulation of an analog link using Fortran. These examples are followed by a consideration of the new 32-bit single-board computers and their potential impact on microcomputer simulation. © 1988 IEEE

Microprocessor Controller For A Multi-Targets System, Shoeineng Lin

Theses

This thesis presents a microprocessor controller for a multi-targets system, which is designed by a direct digital control in the modern computer-aided manufacture system. It is made up of digital control theory, computer hardware configuration and software algorithm. An example is illustrated by IBM PC/XT computer. In this example, the control laws of three simple targets are developed and implemented by C-language. Simultaneously, the computer self-test routines, such as CPU, ROM etc, are developed by intel-8088 assembly language.

Interfacing Of The Digital Spyghnomanometer [Sic] Ds-165 To The Intel 8052ah Basic Based Single Board Computer, Rakesh P. Patel

Theses

The aim of this thesis is to collect the measured data from the blood pressure measurement unit to the single board computer and to store the data for the analysis purposes.

Surface-To-Surface Transition Via Electromagnetic Coupling Of Coplanar Waveguides, Robert W. Jackson, David W. Matolak

Faculty Publications

A transition is investigated which couples coplanar waveguide on one substrate surface (a motherboard) to coplanar waveguide on another substrate surface (a semiconductor chip or subarray) placed above the first. No wire bonds are necessary. A full-wave analysis using coupled line theory is presented and verified experimentally. The use of this transition for coupling to millimeter-wave integrated circuits is discussed.

Transient Stability Simulation By Waveform Relaxation Methods, Marija D. Ilić, M. A. Pai, Mariesa Crow

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a new methodology for power system dynamic response calculations is presented. The technique known as the waveform relaxation has been extensively used in transient analysis of VLSI circuits and it can take advantage of new architectures in computer systems such as parallel processors. The application in this paper is limited to swing equations of a large power system. Computational results are presented.

Computered-Aided Digital Filter Design And Simulatio, Pao-Tsan Chiang

Theses

The simulation is written by C language on AT&T Unix pc 7300 environment, some fundamental mathematics is introduced in the beginning, then digital filter specification method: window, frequency sampling, equiripple are discussed, and Kaiser window method is discussed in details for programming.

There are many problems are met in my simulation, such as F.F.T. aliasing, leakage, Picket fence convolution, correlation, but solutions are proposed.

The result could be output data and graph, GSS_Drivers graph package is utilized, because consideration of operation speed and convenience are emphasized, speed is compromised, but easy to be restructured.

A Dsp Toolkit For The Unix/C Environment Of The Pc 7300 Compute, Suwutchai Jesdanun

Theses

The Digital Signal Processing (DSP) TOOLKIT is a package of programs designed to use the fast Fourier transform (FFT) and display its output responses in graphics form. This tool provides three different window functions and five data modifiers for filter designing and spectrum analysis. Flexible features for modifying the plottings, such as y-axis auto-scaling, xy-axis scaling and center line adjusting of the graphics display, are included.

All programs are written in C programming language for the UNIX System Environment of the UNIX PC 7300 computer. The program structure of DSP TOOLKIT is designed so that modules can be added or …

The Relationship Between Linguistic And Image Based Learning Approaches For Complex Problem Solving: A Case For Computer Generated Animation In Instructional Presentation Of Complex Technical Processes, Stanley T. Bissinger

Graduate Research Papers

The purpose of this study is to provide a rationale for development of new approaches to educating students about complex technical processes. This study may also prove helpful for determining what type of technical content is better suited for computer animated presentation.

An Investigation Of The Uses Of Scanning Electron Microscopy In The Analysis Of The Substructure Morphology Of Semiconducting Devices, Michael E. Courbat

Graduate Research Papers

The purpose of this study is to determine the technical requirements of SEM failure analysis in regard to its' inclusion in the Energy and Power curriculum of the Department of Industrial Technology, University of Northern Iowa.

A Computer-Aided Design And Manufacturing System For Wiring Boards Production, Shiau Chia-Ming

Theses

Our purpose is to build some SBC-8052-BASIC microcontroller based instrument systems, and this thesis integrate resources from two areas into a powerful CAD/CAM system for this purpose. Since wiring board is the most popular used tool for laboratory development and small-scale manufacturing, a microcomputer-aided design and manufacturing system is developed to improve the whole efficiency from wirelisting and wiring sequences to hardware and software debugging. So anytime a circuit theory design stage is finished, the prototype can be made easily, then tested and redesigned, till last stage producing. Several practical wiring board circuits have been made through this system, it …

Microcomputer-Based Automated System To Monitor Flow And Respiratory Quotient, Chung C. Chien

Theses

An instrument system has been designed to monitor Respiratory Quotient experiments on rats which are living within whole-body calorimeters. By using multiplexing techniques, this system is capable of monitoring Respiratory Quotients in six calorimeters (animal chambers). It exhibits some features that make it more versatile than the previous system. One of the features of this instrument is that it uses a more accurate method of determining rapid changes in gas exchange between subject and environment. The value of this method is its ability to assess the rapid change in metabolic rate which occurs as a result of change in activity, …

A Data Compression System Using Arithmetic Code, Seokrim Choi

Theses

Generally it is difficult to compress data, from statistically unknown sources, with significant compression ratio. To achieve this, the compression scheme should have an ability to gather context information of the source, adaptively. For better compression, it is desirable to separate the context gathering scheme from coding itself. Arithmetic code is very flexible and can accept any kind of context gathering scheme which can generate probabilities. One context gathering algorithm which generates Markov type probability adaptively is studied and implemented in software using Arithmetic code. This scheme performs well and results in compression ratio better than any existing algorithms such …

Ksc2408 Digital Filter Evaluation System For The Ecg, Chi-Tong Chung

Theses

A hardware implementation in digital filters by using the high speed and high precision KSC2408 digital filter chips, demonstrates the power of the KSC2408 and proves that the real time digital filters can be implemented without complex circuitry and without high expense.

The system consists of two parts - the digital filter board and the IBM PC; the former handles the data filtering, the latter handles the analog-to-digital data conversion and data display. The KSC2408 is programmed as a 16th order Butterworth digital filter to have flat response in the passband and good attenuation in the stopband.

Reliability Evaluation Of Liquid Crystal Displays Under Accelerated Life Conditions, Rajkumar Krishnamoorthy

Theses

This Thesis shows method of comparing the reliability of Liquid Crystal Display Devices by means of accelerated life testing at elevated temperature and relative humidity for two different vendors.

The tests were carried out at three different combinations of temperature and humidity.

1. 77°±1° C and no added humidity.

2. 85°±1° C and no added humidity

3. 98°±1° C and 98+2% relative humidity.

Leakage current measurements were carried out after every 1000 hours for up to 5000 hours for vendor no.l. Measurements were carried at 0, 500, 1000, 2000, 3000 and 5000 hours for vendor no.2. A DC bias of …

Image Analyzing Instrumentation System For The Activity Measurement Of Rats, Yun-Kang Li

Theses

A microcomputer based instrumentation system has been developed to measure the activity of rats in 12 metabolic chambers. The instrumentation system monitors the rats' behaviors and estimates their activity continuously in an automatic manner. The activity information of the rats are expressed by a quantitative index which describes the intensity of the activity level.

An Apple II microcomputer system is used to manage the activity measurement which consists of an image recording operation and an image analyzing operation. During the measurement, the microcomputer controls Optic RAM digital cameras to record the rats' image. The camera can take a digital picture …

Hardware Based Data Compression System Using Sliding Dictionary Algorithm, Hemant L. Nerurkar

Theses

Popular data compression schemes found in the literature are software based and present innumerable difficulties in hardware implementation. A data compression scheme, which can be directly implemented in hardware using systolic arrays, has been described. The scheme has a remarkable ability to 'adapt' itself to the changing statistics of the source file. Results generated after a comprehensive study and simulations of the algorithm have been presented. The scheme is inherently suitable for parallel processing. It can be incorporated in transmitting devices since it can be fabricated on a single VLSI chip. Comparison has been made with the LZW scheme. A …

Investigation Of The Size Of Gallium Clusters Formed Using A Modified Ion Cluster Beam Source With A Crucible Temperature Of 1250 Degrees C, Sujit M. Shah

Theses

Energy analysis of the ionized gallium clusters was done by retarding field method. The objective of this research was to investigate the possibility of gallium cluster formation during nozzle jet expansion and to estimate the probability of ionization of clusters. The measurements at a crucible temperature of 1250°C corresponding to gallium vapor pressure of 0.23 torr (inside the crucible) showed that no large cluster sizes could be obtained. The relationship between mass deposition rate (atoms/cm2-sec) and cluster size (atoms/cluster) showed that there were two distinct peaks. One with a cluster size of 1 atom/cluster and the other with about 13 …

Method Of Moments Analysis Of Very Thin Wires Using The Mini-Numerical Electromagnetics Code, Douglas F. Stolarz

Theses

The analysis of thin wire antenna systems in the presence of a conducting ground plane is an important engineering problem. This thesis presents an analysis of wire radiators using the method of moments as implemented in the Mini-Numerical Electromagnetics Code (MININEC). Due to singularities in the formulation, MININEC yields inaccurate results for very thin wires. This code was modified by introducing filament currents for very thin wire structures thereby eliminating inaccuracy due to the treatment of singularities.

The modified code was tested on a monopole over a perfect ground, symmetrical and asymmetrical dipoles in free space, and inverted L and …

Weighted Least Square State Estimation In Power System, Jinn-I. Wu

Theses

In this thesis two methods for power system real-time monitoring are presented, programed and tested. Method 1 is not new and method 2 is a modification of method 1. The two methods are comparable in performance and they solve the problem satisfactorily.

These methods are iterative and the problem of choosing a convergence criterion is unexplored yet. This problem has been discussed, guidelines are presented to select an optimal convergence criterion.

The concept of confidence level and techniques for error detection are investigated. programs to detect bad data and to establish a confidence level have been written and some tests …

Implementation Of Xilinx Development System And Xilinx Lca Application, Youcheng Wu

Theses

The Xilinx Application-Specific Integrated Circuit (ASIC) is a large array of programmable logic cells. Creating logic design using the Xilinx ASIC offers ease of implementation, high function density, design flexibility and lower consumption of supply power. The techniques of implementation of system and design with Xilinx CAD/CAM System include system analysis, modification, update, optimal design algorithms and real circuit emulation.

This thesis combines the setup and operation of the complete Xilinx system, and implement Xilinx LCA into 8052AH-BASIC based Single Board Computer and user's menu of real LCA chip evaluation Board. It presents our own design, construction, test and demonstration …

Mizer : A Ruled Based Cad Tool For Logic Optimization, Sandip Mukerjee

Theses

This objective of this research was to develop a knowledge based CAD tool, to address the problems of Logic Design. MIZER is an expert system, that accepts functional specifications of a logic circuit and connectivity description of its implementation to generate an optimal design. This information is then used to develop a hazard free circuit that brings about an optimization in area and timing. It stores the newly created design into its knowledge base with the approval of the designer, for future use.

Digital Signal Processing Implementing The C Language With Graphics Spectrum Analysis Display, Anuraksa Mahanirananda

Theses

Digital Signal Processing discussed in this thesis is concerned with the transformation of signals or complex wave forms From time domain to frequency domain and vise-versa, implemented on microcomputer systems. The primary principles are: speed of transformation, ease of usage as an application program, capabilities of graphics displaying transformed data (such as power spectrum analysis), storing these data onto record files, and capability of using these data Files and programs with other application programs.

We begin by discussing briefly, the concepts of Fourier theory, Discrete and Fast Fourier Transform, algorithms of Fast Fourier Transform and bit-reversal. Then we implement these …

Performance Of Second Order Delta Modulation System, Reza Aghazadeh Alavi

Theses

The performance of an ordinary delta modulation (DM) system under three types of input signals was investigated. These signals were band limited Gaussian noise, 800 Hz sine wave, and speech signal. The affects of 2nd DM added to the ordinary DM in improving the performance of the system were researched. This is called a Second Order Delta Modulation System. The obtained data showed an increase of about 3dB in the overall Signal to Noise Ratio (SNR) of the system, in the worse case.

Input to the 2nd DM is the band limited error of the first DM. A linear phase …

Microcomputer-Based Automated Feeding And Monitoring System For Eating Behavior Studies On Rats, Tseng-Huang Shih

Theses

An instrumentation system has been designed to monitor feeding behavioral experiments on rats. This instrumentation system is capable of performing these experiments in an automated manner without any human intervention. It is capable of monitoring these experiments concurrently in six cages. It exhibits several features that make it more versatile than previous feeding & monitoring systems. It is also capable of storing the data generated on to a floppy disk and later printing out the data for analysis.

Another feature that makes it more versatile is the flexibility of the system. Construction of a parameter file before doing the experiment …

Optically Phased Laser Transmitter, Janet S. Fender, Salvatore J. Cusumano, Robert R. Butts, Christopher R. Dehainaut

AFIT Patents

An apparatus and technique are described for phasing the outputs of a multiplier telescope array used as a laser transmitter. The technique uses samples of the transmitted beams to control optical path lengths through the separate telescopes so that the beams add coherently at the receiver. The phasing concept is applicable both to systems which provide inputs to the multiple telescopes by dividing a single laser beam and to systems in which the inputs to the telescopes and multiple, phase-locked laser beams. The approach is also compatible with single line and multi-line lasers, and it does not entail stringent alignment …

Computer Simulation Of Dynamic Systems, Charles G. Smith

Retrospective Theses and Dissertations

Computer simulation of a control system is a valuable tool in design or performance evaluation. This is especially true when non-linear elements cannot be ignored and must be included within the model. A general purpose block diagram oriented simulation program will be developed which can utilize continuous, discrete and non-linear building blocks. The software tool will be demonstrated by means of an example.

Ada Tools For The Description And Simulation Of Digital Signal Processing Systems, Mark D. Happel

Retrospective Theses and Dissertations

While specialized hardware description languages allow for maximum capability and efficiency in a design automation system, the use of a general purpose language in the same role can make the system more available or more available or more practical for a larger set of users. This project demonstrates the use of ADA* for the description and simulation of small digital signal processing systems. Building on conventions and primitives proposed by Denyer and Renshaw, a simple subsystem was described in ADA and then tested with a small simulator also written in ADA.

* ADA is a trademark of the United States …