Digital Commons Network^™

A Word Based Data Compression Using Arithmetic Encoding, Christopher Dean Peckham

Theses

It is usually difficult to compress data from a statistically unknown source and yield a good compression ratio. Using the fact that words are the fundamental basis of the written language, a data compression scheme based on words should yield high compression ratios. Discussed here is a compression scheme that gathers words from the source stream and places them in a dictionary, or word list, to use later in the coding, thereby becoming adaptive to the words in a given file without prior knowledge of the source. When a word is in the word dictionary, it is encoded by its …

Assessment Of Autonomic Regulation Of Heart Rate Variability, Shaw-Jyh Shin

Dissertations

Complex demodulation, accompanied by the techniques of interpolation, detrending and zero-phase-shift lowpass filtering were used to examine the effect of both divisions of the autonomic nervous system (sympathetic and parasympathetic) on heart rate by analyzing the heart rate variability signal from dogs under two different classical conditionings: CS+ and CS-, which cause different dynamic pattern changes in the autonomic nervous system to regulate the heart rate.

Unlike power spectral analysis, complex demodulation gives results in the time domain and shows the variation of amplitude and phase over time at a given frequency. The variation of phase indicates the frequency deviation …

Rf Characterization Of A Directly Modulated Ingaasp Buried Heterostructure Laser Diode, Charlotte Alvarez

Theses

The use of fiber optics for the transmission of microwave signals had its beginnings in 1984. Applications were limited to the lower microwave frequency regions. Technology in this field is advancing rapidly due to the high demand driven by the telecommunications community for high speed digital applications. Extensive research and development efforts are underway by both the component manufacturers and the subsystem end user. Most of the near term applications of microwaves in fiber optics are in weapon systems and communication systems for military and other government agencies.

The high frequency modulation characteristics of Lytel's InGaAsP 1300 nm buried heterostructure …

Design Of Bridge Inter-Connecting Token Ring & Token Bus Local Area Networks, Kasinath Anupindi

Theses

A Bridge interconnecting two Local Area Networks has been modelled. The two interconnected networks are the Token Ring and the Token Bus LANs. Concepts of Queueing theory have been employed in the design. Initially it is assumed that the buffer size at the Bridge is infinite. Further it is assumed that the arrival rate of the messages is Markovian and the service rate is General, Le it is an M/G/1 system. Expressions for the average waiting time at the Bridge and the size of the buffers is computed. Graphs for various parameters have been plotted. Based on these graphs the …

Data Flow Dependency Generator, Chin-Piao Chan

Theses

Data flow is a new approach to parallel computing. The concept is to enable the execution of an instruction whenever its operands become available. The only constraints in a data flow machine are the data flow dependencies between instructions.

In this thesis, a simulation package called the Data Flow Dependency Generator is developed. This package is designed to express the idea of data flow computations, the data flow dependencies and the use of multiprocessors.

Given a number of processors, a number of time units for each operation and a program, the Data Flow Dependency Generator finds the data dependencies between …

A 3-D Tactile Sensor With Digital Output, Sin-Shou Cho

Theses

This thesis details the design of a new tactile sensor for general-purpose robot manipulators. Such manipulators, designed to be functionally equivalent to the human hand, will require sensor arrays that fulfill several requirements : (1) many sensor elements to minimize tactile imaging time, (2) close spacing of small sensing elements for fine spatial discrimination, (3) ability to be molded to a convex fingertip surface for taction on concave surfaces, (4) tolerance to over-scale forces without damage. In addition to the above, which are considered requirements, several other characteristics are desirable. Foremost is the ability to sense shear forces, which provide …

A Computer-Based Microwave Interferometer Instrumentation System As A Non-Invasive Cardiopulmonary Monitor, Chin-Yee Eric Ho

Theses

The system comprises a microwave interferometer as a computer-based non-invasive cardiopulmonary monitor. The microwave interferometer records the mechanical vibration of the chest wall. The objective is to determine whether the signals may have diagnostic value and to evaluate the instrument as a non-invasive and non-contacting cardiopulmonary monitor.

With the help of a computer it is possible to analyze the mechanical vibration of the chest wall produced by the heart and thereby detect, and possibly categorize, cardiac abnormalities. This system is able to process two channels, the first signal from microwave interferometer records chest wall vibrations and the second signal is …

Apap: The Arithmetic Pipeline Analysis Package, Chang-Chieh Lin

Theses

This study is aimed at the development of an interactive PC-based package for simulating data flow within an arithmetic pipeline in multiprocessor systems. The user constructs the arithmetic pipeline, specifying the functionality of each segment, the intersegment connectivity and pipeline inputs and outputs. After defining reservation tables and data, analysis is performed with the results available in tabular, simple graphic and animated graphic forms.

APAP allows the user to design hardware and analyze its functionality with-out building the circuit, an economical alternative. Even when circuits are to be built, APAP allows the user to correct logic errors before implementation, leaving …

An Analysis Of The Second-Order, Type-One Hilbert Phase-Locked Loop, Inn-Shian Lin

Theses

In this thesis, a second-order, type-one PLL ( Phase- Lock, Loop ) in which the usual lead-lag loop filter is paralleled with a Hilbert Transformer (the whole system is called HPLL) is analyzed. A motivation for the study was that earlier researchers have found improved performance if Ilse lead-lag network is paralleled by a differentiator, result mg in the so called ERPIM (Extended-Range Phase-Locked Demodulator). For the purpose of com-parison with earlier experimental and analytical results on the PLL and the ERPLD, the numerical results in this thesis ale based on the parameters of Acampora and Newton.

The basic characteristics …

Simulation Study Of The Multi-H Continuous Phase Modulation, Min-Ling Lin

Theses

Of particular interest in satellite communications are modulation techniques that have a relatively constant envelope and are power and bandwidth efficient. Attempts have been made to satisfy these requirements by using phase and frequency modulation formats. Recently, one approach has been researched which combines the modulation and encoding functions, which is referred to as multi-h continuous phase modulation. Simultaneously good power and bandwidth efficiencies can be achieved at the expense of increased complexity.

This report examines the performance of multi-h continuous phase modulation by a simulation. A multi-h phase coded modulation is generated, passed through the AWGN transmission channel. The …

Independent Equations Method For Power System State-Estimation, Shun-Gee Lin

Theses

The problem of power system state estimation (PSSE) is to convert the available. redundant and noise contaminated measurements, and other information into a best estimate of the state of the system.

Methods to solve the PSSE, including the sub-problems of bad data presence detection, identification and reconstruction, are reviewed. The Independent Equations Method (IEM) was selected for in-depth study and analysis.

The tree method for bad data identification is tested and failed due to the suspected ill-conditioning of the sensitivity matrix. For bad-data reconstruction, the IEM fails as described. Modifications that saves computing time and ensures reconstruction success are presented …

Interface To 8052ah-Basic Microcontroller For A Multichannel Priority Interrupt System, Chen-Tung Mo

Theses

This thesis presents the design and development of a system with the capability to detect up to forty channels of signals generated from different analog sources and to process them under the control of a microcomputer.

The present work offers the design and implementation of a hardware interface unit in a multichannel real-time data acquisition system as well as the application software program to operate it. This kind of system can be widely used in process control, musical instrument interfacing, and machine automation.

This interface unit follows the general instrumentation architecture in both signal processing and logic control. The software …

High Frequency Gaussian Beams Solution Of A Plane Wave Coupling Into Cylindrical Cavity, Christine Issa Mourad

Theses

Propagation of high frequency fields as a superposition of Gaussian beams instead of geometrical ray fields has potential advantages in complicated environments because the beams do not fail in ray optic transition regions. While the Gaussian beam method can be made rigorous through self consistent stacking of displaced and tilted beams on a Gabor phase space lattice, with retention of full beam spectra, computation is facilitated when the propagation domain is covered with paraxially approximated nontilted beams. The spectral deficiencies introduced by this simplified propagation model depend on the propagation environment. They are examined here for a plane wave coupling …

Design Criteria Of Coherent Optical Fiber Communication System, Rajesh N. Patel

Theses

Design criteria of coherent optical fiber communication system were discussed and investigated. First, the different types of optical fibers (waveguides) were discussed. Then the laser sources, photo-detectors, transmitter & receiver circuits were discussed in detail.

Design criteria of conventional intensity modulated (direct detection) optical fiber communication system were discussed. Then, the design criteria and estimation of number of photons for different modulation schemes for coherent optical fiber communication system were analyzed.

Coherent optical fiber communication system's advantages and drawbacks were discussed in detail. Improvement in receiver sensitivity of coherent detection compare with conventional direct detection was investigated. Finally, some receiver …

System Performance Criteria In Cdma Networks Using Gold Codes, Yong H. Kim

Theses

First, we have presented the autocorrelation and crosscorrelation properties for periodic and aperiodic binary sequences. The generation of binary sequences using shift registers with feedback was reviewed. We have also included correlation properties for the Gold codes.

Next, we discussed Gold code generation for the balanced and unbalanced Gold codes.

Thirdly, we investigated the number of simultaneous users in a CDMA system using Gold codes for the worst case and the average case of mutual interference.

Finally, we simulated the probability of interference exceeding a threshold value, and the average crosscorrelation value caused by interference in a CDMA network which …

Modeling And Simulation Of Robot Arms With Flexible Links, John G. Danis

Theses

The design of lightweight robot arms introduces a degree of flexiblity in the individual links which renders the arm difficult to control. Solution of the control problem requires accurate and detailed mathematical models of the arm dynamics. A comprehensive survey of the current literature in this area has shown that although many such models exist, there is a great diversity in their structure, function, and applicability. The different objectives and techniques of model development which lead to this diversity are examined and summarized in this thesis. Bases for classification of the mathematical models and techniques of development are established, and …

Design And Development Of An Infrared Ccd Camera, John Frederick Romanowich

Theses

An infrared CCD camera system was designed and developed for operating various sizes of Schottky-barrier IR-CCD image sensor chips. The camera has a digitally programmable frequency synthesizer for operating the 160 X 244, 320 X 244, and 256 X 256 image sensors developed at the David Sarnoff Research Center. The electronics of the camera are designed to provide the outputs required for operating a XYZ monitor, a standard TV monitor, or a computer workstation. At the core of the camera design is a RS-170 standard sync generator that supplies the waveforms for synchronizing the camera's circuitry to produce a composite …

Analysis And Simulation Of Chirp Radar System, Tina Tsung Tsai

Theses

This paper consists of a technique to design a Chirp radar system and proposes a solution to optimize the design of the linear time delay network required in such systems. A Chirp radar system has a wide bandwidth for high range resolution, and long pulse duration for high velocity resolution and high transmitted energy. The technique of a pulse compression system offers a means of increasing the average power available to illuminate radar targets without any loss of the resolution at the receiver needed for the tactical requirements of the system. This is accomplished by transmitting a wide pulse in …

Attenuation Properties Of An Lp 11 Mode In A W-Type Fiber Operating Below Cutoff, Chih-Chiang Wang

Theses

Rigorous formulation of a W-type fiber for its dispersion properties is presented. An LP mode has been studies extensively with respect to its attenuation properties when the frequency of operation is kept below cut-off. Due to rigorous dispersion equation numerical difficulties encountered in the computations, an approximate dispersion equation corresponding to weakly guided modes is solved. Numerical results corresponding to attenuation and propagation characteristics of the W-type fiber for radii and refractive index variations are presented. A computational subroutine for radial functions (Bessel, etc ) for complex argument has been used and proved to be useful in the legion of …

Schema Based Wiring Tool : A Computer Network And Cad Design System, Jia Jing Zhang

Theses

For the purpose of building a SBC-8052-Basic micro-controller based instrument system, a new SCHEMA II Computer Aided Design system for IBM-PC is used to enhance circuits design routine, and it is described here. The new features of this CAD are discussed, and the design example of a new version of the SBC-8052-Basic micro-controller is given here in detail.

Since the wiring board system is adopted as tool of the laboratory development and controlled by the QL microcomputer, and since SCHEMA II CAD, on the other hand, is used on the IBM-PC-AT, communication between the two microcomputers is accomplished, and the …

C/Ku Band Satellite Television Reception System, Costas A. Economides

Theses

The purpose of this thesis is to examine and investigate the design of a satellite reception system able to receive most C and Ku band North American geostationary satellites' TV transmissions. The performance criterion used for the system design is based on a required demodulated video signal-to-noise ratio maintained for a specified percentage of time in conjunction with overall cost considerations.

Furthermore, a computer program written in FORTRAN 77 is developed, which among other functions lists the notified, operational, geostationary satellites in sight with their corresponding look angles, from any given location on the earth.

Design Of A Fiber Optic Oxygen Sensor Based On Immobilized Hemoglobin, Mendu Govind Raj

Theses

The fiber optic Oxygen sensor consists of a thin layer of immobilized deoxyhemoglobin at the common end of a bifurcated fiber. Immobilization is done using the alginate gel procedure. The immobilized reagent is separated from the standard oxygen sample by the gel with or without semi-permeable membrane, and the entire configuration is enclosed in an oxygen free sample cell. Light from a tungsten-halogen lamp, filtered through a 405nm filter is passed through one arm of a bifurcated fiber to the sample cell. The reflected intensity (a highly polished aluminum foil or a plate is placed at the bottom of the …

Ibm/Xt-Based Automatic Monitoring Instrumentation System For Eating Behavior Studies In Rats, Binghong Gui

Theses

An auto-feeding system based on the IBM-XT microcomputer has been designed for use in the anti-obesity research program in the Pharmacology Department at Hoffmann-La Roche Inc. By using this system, experimental rats can be automatically fed, some which have been given anti-obesity drugs and some which have not. The system can also collect data, such as eating times and food intake, which are used for studying the rat's eating behavior.

The system is designed to control thirty six cages with one experimental rat in each cage and it performs three functions:

1 ) To automatically dispense a preset quantity of …

A Dynamic Set-Based Multiaccess Protocol For Local Area Networks, Parul S. Nanavati

Theses

The packet-broadcasting technique brings together the advantages of both packet switching and broadcast communication. The central problem of a packet broadcast network is conflict resolution among the users sharing the broadcast communication link. Collisions are the major source of transmission errors which degrade the performance of a LAN. Proposed here is a novel multiaccess protocol which offers full communication resources to the user at low traffic requirements. It dynamically adjusts the number of users allowed to access the medium at heavy traffic requirements such that number of collisions are reduced and thus maintains the efficient utilization of the medium and …

Reliability Problems In Semiconductor Lasers, Ajay R. Patel

Theses

The stability and reliability of semiconductor laser is dependent on its design, fabrication, and output power. The best way to assure high reliability of these devices is by accelerated aging test and by selection of strict and meaningful criteria for the acceptance or rejection of a particular device. In this thesis emphasis is given on different failure mechanisms that are known. As new development takes place, other mechanisms may be found. Catastrophic degradation, gradual degradation, darkline defects, and contamination during the fabrication process are the main source of device failure.

The noise generation and the packaging issue of semiconductor laser …

Microprocessor Testing And Computer Aided Diagnosability Of Digital Circuits, Shirish Patel

Theses

Computer Aided Diagnosability Of Circuits (CADOC), a new method is developed for isolating and pin-pointing a faulty device in digital circuits. CADOC is based on graph-theoretic principle and PFD numbers. Without considering any SA1 or SAO faults, we can zoom out faulty device by selecting different diagnostic path to narrow down the faulty region and to isolate the faulty device. The efficiency of this new technique is confirmed by applying the technique to many examples.

Reliability Evaluation Of Liquid Crystal Displays Under Accelerated Test Conditions, Ishatdev Singh Rathore

Theses

This thesis deals with the recent study of reliability of liquid crystal displays. This study determined the effects of high temperature on LCD reliability. To accomplish this, reliability life testing was done on different kinds of LCD samples under different operating conditions. The tests were carried out on the samples of two different vendors at two different temperatures. No humidity was added in any test.

Vendor No. 1

1. 120 units at 77° ± l° C.

2. 80 units at 85° ± 1° C.

Vendor No. 2

1. 60 hard and 60 soft glass units at 77° ± 1°C.

2. …

Analysis Of Spread Spectrum System Using Direct Sequence Technique In Jamming Environment, Kandarp A. Vyas

Theses

A spread spectrum system is a means of transmitting data over a channel In addition it offers a wide variety of features like data security and signal hiding This work studies in detail a spread spectrum system using direct sequence binary phase shift keying. The Sliding Correlator and Sequential Detector techniques have been used to achieve synchronization. A brief study of pseudorandom noise has been presented. System was simulated on UNIX using 'c'. A modified version, suitable for software implementation, of Sliding Correlator and Sequential Detector was, used. Results generated using tins model are presented here.

An Investigation Of Interrupt Handling Schemes In Pipeline Processors, Shailesh Ratilal Gami

Theses

In order to acheive higher performance in a pipeline processor, proper interrupt handling is essential. In a pipeline processor, interrupt handling is difficult because many instructions are in the processor at the same time. This study describes and evaluates the different solutions to interrupt handling. Several pipelined 32-bit microprocessors have also been studied and their architectural and programming features are compared.

Performance Of Single Dwell Serial Synchronization System, Chan-Yee Hsiung

Theses

By using the sampling theorem, the problem of the detection of a signal in white Gaussian noise, reduces to the consideration of the sum of the squares of statistically independent Gaussian variates. If the transmitter and and receiver are not synchronous, then no data transmission is possible and the decision statistic has a central chi-square distribution. Otherwise, the decision statistic has a non-central chi-square distribution. Also, this. paper presents a method to calculate the mean and variance of the acquisition time which are the most important parameters to evaluate the performance of a PN spread synchronization system. In addition, the …