A simple approach to developing approximate analytical
performance models for complex systems (such as distributed
processing systems or computer networks) is presented.
The approach is applicable in cases where measurement
or simulation data describing system performance are
available but the system is too complex for exact analytical
models to be...
The suitability of discrete least-squares optimal (Wiener) filters
for deconvolution of tone-burst waveforms is studied. It is shown
that: (1) such waveforms are not well suited to these filters without
preprocessing, (2) the use of exponential weighting results in a significant
improvement in filter performance and (3) that "phase-unwrapping"
in...
An application of the theory of conditionally Gaussian random
processes to filtering and stochastic control problems is presented
here. The results due to Liptser and Shiryayev are proved to hold
in the multidimensional case under somewhat relaxed conditions,
when compared to the original ones. Such a generalization is required
from...
The problem of synchronization arises in the interaction among
digital systems not sharing a common clock reference. The reliability of synchronizers is related to metastable operation of
bistable elements. Because of its subtle nature, the phenomenon
until recently was not widely researched. However, the literature
now contains a sound theoretical...
Regular structures such as PLA's are very
important to reduce VLSI design time. Interest in CAD
tools such as a practical reducing PLA generator is high.
This dissertation presents PRONTO as a practical, near-optimal
product term reduction method, whose general
heuristic approach consists of the following four steps.
First, select...
This paper corrects an apparent deficiency in the published
information concerning Hardware Description Languages (HDLs) by
introducing and discussing an approach for selecting an HDL for
use in a design project. Although three classes of HDLs are discussed
in this paper, High-Level Languages (HLLs), General Purpose
Simulation Languages (GPSLs) and...
The electrical and optical properties of semi-insulating, epitaxial and ion-implanted GaAs and InP have been characterized and analyzed. Electron and hole traps in semi-insulating GaAs and InP, with activation energies ΔE[subscript T] ranging from 0.16 ± 0.01 to 0.98 ± 0.01 eV, have been detected and characterized by Photo-Induced Current...
This thesis reports on an investigation of the growth, by
Molecular Beam Epitaxy, of III,III-V ternary compound semiconductors.
Strained and unstrained growth was studied via the deposition of InGaAs
on GaAs and InP substrates. Lattice matched InGaAs on InP was grown,
and an in situ method was developed to find...
A new approximation technique to a certain class of nonlinear
filtering problems is considered in this dissertation. The method is
based on an approximation of nonlinear, partially-observable systems
by a stochastic control problem with fully observable state. The
filter development proceeds from the assumption that the
unobservables are conditionally Gaussian...
In microwave network analysis, proper matching of the measurement system is necessary to prevent measurement errors and provide a
proper terminating impedance for the device-under-test. To obtain
this matching, a buffer amplifier is often used in the first stage of
the network analyzer.
This study describes the design and analysis...
Accurate and efficient computational methods to evaluate the
quasi-TEM parameters of various planar structures such as microstrips,
coplanar lines and coplanar waveguides are developed. The characteristic
parameters of all these structures which are used extensively
in microwave integrated circuits for applications as transmission
lines and other circuit elements are computed...
Linear phase variable filters that are obtained with a frequency transformation of the form cos(ω) = P(cos(W)) were analyzed, where P is a finite degree polynomial, ω is the prototype frequency and W is the transformed filter frequency. A new transformation of third order is proposed. The new variable filter...
The problem of optimization of stochastic dynamic systems with
random coefficients is discussed. Systems with both Wiener processes and uncertain random-process disturbances are dealt with in
this dissertation, and these include certain bilinear stochastic
systems. It is the purpose of this thesis to study the optimal control and, to some...
Frequency domain design of deconvolution filters is
studied using Fast Fourier Transform. Filters for both the
spike and the Gaussian reflector wavelet are obtained. True
deconvolution filters are infinitely long IIR filters,
and frequency domain analysis is an effective way of
finding its optimum finite length approximation for an
arbitary...
The scope of this project was to build a high
energy impulse generator to be used for educational
and research purposes, such as small scale modeling
of lightning and switching surges or small scale
simulation of an electromagnetic pulse (EMP).
A one-stage impulse generator was designed to
deliver a voltage...
Two-way transmission of data on broadband community cable television systems is considered in this thesis. A discussion of the data transmission environment is presented which attempts to characterize the channel noise and interference which degrades data transmission performance. The analysis considers channel degradation resulting from additive gaussian noise and various...
White electroluminescence (EL) was observed for the
first time from diamond-like carbon (DLC) films at room
temperature. Electroluminescence was observed by the
application of ac voltages in excess of 200 V to a metal-insulator-
semiconductor (i.e. DLC)-insulator-metal (MISIM)
device structure.
For EL applications, three types of the DLC films were...
The objective of this thesis is to describe the design and
implementation of a VSLI reduced instruction set computer (RISC).
The RISC machine constitutes a new style of computer architecture.
It differs significantly from the complex instruction set computer
architectures (CISC) of the past. RISC architectures are
characterized by their...
The major goal of this research work was to develop better
electrical measurements for the evaluation of silicon material
quality.
The first approach investigated was the Zerbst generation
lifetime measurement technique. It was demonstrated that the
error in the estimation of the generation lifetime obtained with
this technique could be...
This thesis presents a simulation technique for the
post-detection of a point-source trajectory in an
isotropic, stationary random medium. The two-dimensional
source location is estimated from spatially correlated
angle-of-arrival data which are collected simultaneously at
two sensor positions. We assume that the data are collected
at discrete, constant time intervals...
As a result of the automation revolution, robots
are assuming ever more complex and demanding tasks.
Robot system control schemes for fast and precise robot
motion require utilization of the entirety of the robot
dynamic formulations and the ability to evaluate these
formulations in real-time. The dynamic formulations,
which take...
A microprogramming teaching tool was designed and implemented. This tool was based on the Am 2900 bitslice microprocessor family. It provides tools for understanding software development for a simple bitslice microprocessor.
A compartmental model of lymphocyte circulation
through a lymphnode is derived and simulated. The
purpose of the model is to analyze experimental data and
in turn design experimental plans from the analysis in
order to obtain sufficient data for the organ-distributed
immune response. The model will be used to predict...
The U.S. Air Force models many naturally occurring
phenomena. To validate such models, an automated data
collection system is used. Since validation is dependent
upon correct data, an inexpensive method to detect
erroneous data was investigated. The method uses a Wiener
filter to predict values one sample in advance. If...
In this research, a novel shunt compensation scheme
design procedure is developed for unbalanced, untransposed
n-phase transmission lines. The main function of the
scheme is to reduce the effect of the capacitive coupling
on untransposed transmission lines to levels where successful
single-pole switching is assured. The analysis procedure
is carried...
The sliding mode controller, based on the theory
of the Variable Structure System (VSS), is considered
for a robot manipulator. By consideration of VSS theory,
the nonlinear interactions of manipulator dynamics
are suppressed by use of linear sliding equations, and
VSS robustness with respect to the unknown physical manipulator
parameter...
This paper discusses the design strategies for interface of bus
architectures. It also describes the design of interface between the
two popular bus architectures, the Micro Channel and the Nu Bus.
The main objective of this thesis is to develop a procedure for
bus interface design and use this procedure...
Recently, switched-current circuits have received great
attention because they offer potentially better performance in terms
of speed, low voltage power supplies, and accuracy in mixed-mode
analog-digital signal processing. In this thesis, the distortion
characteristics, DC offset and AC gain errors induced by the threshold
voltage, channel width, channel length, and...
A highly flexible numerical simulation model for the performance
prediction of brushless dc drives is presented, which is capable of
investigating unbalanced and asymmetrical operating conditions as well
as drives with non-ideal parameters. Numerical speed-up procedures
allow for the investigation of pulse-width modulated (PWM) drives using
a personal computer. Experimental...
Ever-increasing size, complexity and operation costs in modern
power systems have stimulated the intensive study of an optimal
Load Shedding and Generator Rescheduling (LSGR) strategy in the
sense of a secure and economic system operation.
The conventional approach to LSGR has been based on the application of LP (Linear Programming)...
A short-circuit-protected line-driver circuit is
particularly adapted for use in a CMOS differential line-driver
system, where one line-driver circuit provides a
true output signal, and another line-driver circuit
provides a complementary false output signal. A short-circuit
is sensed by measuring current through a secondary
pull-up transistor, and disabling a primary...
Team pursuit-evasion games are studied here with one performance
index for the team as a unit in competition with one common opponent.
Particular structures of team games are discussed after a brief introduction
of the two-player differential games. The classical calculus
of variations is used to derive the feedback strategies...
Local computer networks are being installed in diverse application areas. Many of the networks employ a distributed control scheme, which has advantages in performance and reliability over a centralized one. However, distribution of control increases the difficulty in locating faulty hardware elements. Consequently, advantages may not be fully realized unless...
The electrical properties of ion-implanted GaAs FET channels
are investigated by two methods. First, the channel current (I) as
a function of voltage (V) is examined at different temperatures and
using different voltage ramp rates. The standard FET I-V curve,
which can be observed on a commercial curve tracer, is...
Morphological filters have shown good performance in various image processing applications. Furthermore, their algorithms are easy to implement in special architectures, with the exception that linear filtering cannot be implemented in many of these cases. In this study, a new architecture and corresponding algorithm, capable of realizing linear shiftinvariant filters,...
The system in this thesis uses multiple Intel iSBC86/12A cards
connected to the Intel Multibus. The system was written using the Intel
language PLM86. The final result is a low level debug tool that
provides the user with the following capabilities: examine/change
memory, examine/change processor registers, load a user written...
Minimizing the number of product terms in a PLA implementation is a large step
towards saving area on a VLSI chip using PLA logic. Due to the large amounts of computer
time necessary to achieve this minimization, a number of heuristic approaches have
been developed to provide near-optimal solutions in...
This paper describes the design and implementation of
"A multiprocessor node for communication and control"
(MPCC). MPCC is a high speed, high performance local area
network capable of performing real time control tasks. This
is achieved by the concurrent operation of two 8051
microcontrollers, a dual port RAM and the...
An important task of a Variable Speed Generation (VSG)
system is the capability to maintain and control the terminal
voltage at some desired value as determined by the
reactive power dispatch strategy.The main objective is to
design a sub-optimal fixed-parameter controller in the
sense that constraints with respect to practical...
The resolution of multiple overlapped reflections is
achieved by designing inverse filters using frequency
domain deconvolution. A careful study reveals a number of
problems involving frequency domain design of spike inverse
filters. These include the presence of noise and aliasing
in both the filter response and its output resulting from...
The core area of a conventional CMOS digital gate
array consists of only one size of NMOS device and one
size of PMOS device. Both primitives have fixed minimum
channel lengths, and this has significantly impeded analog
applications. This work has shown that by forming series
and parallel interconnections between...
A design style is presented for a self-synchronized,
multiple input change, asynchronous state machine which
processes input changes at a speed limited only by the
required machine behavior and implementation technology.
This state machine will operate at this ultimate speed
because of a new asynchronous delay element with unequal
rising...
We extend previous results for optimally scheduling
concurrent program modules, called tasks, on a fixed, finite number
of parallel processors in two fundamental ways: (1) we introduce a
new heuristic which considers the time delay imposed by message
transmission among concurrently running tasks; and (2) we
introduce a second heuristic...
Two new medium access protocols for ring type local area networks,
CTR (Concurrent Token Ring) protocol and DRUID (Destination Removal
withoUt Intermediate node Delay) ring protocol, are proposed, designed and
analyzed. A destination partial removal technique is designed and used in
these two protocols to support concurrent message transmission and...
"Expert systems" is an area in the field of
artificial intelligence which attempts to encode an
"expert's" heuristic knowledge and reasoning ability into
a computer program. The purpose of this study is to
investigate the applicability of using an "expert system"
in a closed-loop automatic control system.
An "expert system"...
The synchronous machine is an essential component of a power
system and determination of its parameters accurately is an
important task in securing adequate modes of operation through
certain control strategies. An estimation technique based on the
Powell algorithm was evaluated for the identification of these
parameters on the basis...
Rapid advances in technology have seen computing move from a
large central computer to desktop microcomputers.
This advance was also
seen in the design of dedicated computers, computers designed to perform a
few specialized tasks or duties.
These computers, or microcontrollers, are
often controlled by a central computer and themselves...
A frequency compensation technique for increasing the
settling speed of two-stage operational amplifiers used in
switched-capacitor applications has been developed. By
properly decompressing the pole-zero doublet to form a
three-pole one zero system, the settling speed is increased
up to 50 percent as compared to the optimized two-pole
system.
Control algorithms for accurate and fast moving robots require the use of the complete dynamic model of the robot. The complete dynamic model takes into account the nonlinearity and coupling terms of the whole structure. The time of computing the dynamic equations determines whether they are usable in practical applications....
PRONTO is a direct, one-pass heuristic method designed
to shrink the size of reducible programmable logic
arrays. Several people have contributed to the design,
and translation to a computer program, of this attempt to
produce a good solution quickly. This thesis discusses
efforts to improve PRONTO's implementation in order to...
The rapid development of semiconductor technology and the increasing complexity of VLSI chips have prompted both the industry and the
academic community alike to take an indepth look at the VLSI design
problem. Many design methodologies have been proposed and associated
computer-aided tools developed. This thesis is a study of...
The photoresponse behavior of semi-insulating GaAs is
investigated. The photocarrier lifetime is discussed and
the influence of surface and contact recombination is
taken into account. Photocurrent-voltage characteristics
have been measured and a mechanism for the gain in terms
of space charge amplification and avalanching is suggested.
The influence of deep...
The B lymphocyte is the immune cell responsible
for the production of antibodies. It has receptor
molecules on its surface which bind to a molecule known
as an antigen. The antigen either stimulates the cell
to produce antibodies or tolerizes it so that it is
unable to produce antibodies.
It...
Mathematical models for the doubly-fed machine are
presented. The properties of the machine with rotor excitation as supplied by a power converter with voltage
source character are reviewed. The peculiar torque-speed
characteristic of the machine in this operating mode and
its effect on the stability of the machine are presented....
A MOS biquadratic (biquad) filter employing the switched-current technique is
reported. The circuit uses current-mode processing which can offer wide
bandwidth, low voltage operation, and can be implemented with standard CMOS
technology. Examples of lowpass, highpass, and bandpass filters are given
which illustrate the synthesis procedures and the versatility of...
Conventional generators are operated at fixed speed,
and they lack the advantage of Variable Speed Generators
(VSG) i.e.a VSG system is capable to maximize the electromechanical
energy conversion process by varying the shaft
speed. This thesis deals with a VSG system which also
preserves all the functional features of a...
In this is paper, an implementation of a microprocessor
based distributed control system (DCS) is investigated. This
system consists of a digital PID controller and a high
level operator interface. A temperature control system
was designed to experimentally verify the system operation.
Experimental results compare closely with theoretical
prediction. The...
This paper describes the design and implementation of
COLAN V, a High Performance Local Area Network for
Communications and Control utilizing a Communications Coprocessor.
The main objective of this thesis is to improve upon
the performance of previous COLANs in speed, switching
techniques and error detection techniques. This was
possible...
Typically, a Floating Point processor will be
attached to a general-purpose digital computer to extend
and enhance its numeric processing capabilities. In this
thesis a multiple instruction, multiple data machine for
the addition, subtraction, multiplication and division of
floating point numbers is presented. The algorithms used
have been partitioned to...
The output characteristics of a conventional GaAs depletion-mode MESFET device have been investigated. One of the important parameters of the small-signal GaAs MESFET model, g[subscript ds] (output conductance), is shown to be frequency and temperature dependent. Variations in g[subscript ds] are a serious problem in many analog and digital circuits...
The properties of linear active coupled lines consisting of
electrically long GaAs MESFET structures are investigated for possible
applications as traveling-wave broad-band amplifiers. In addition,
the nonlinear coupled Schottky lines are studied for applications as
voltage tunable circuit elements.
The analysis of the general active asymmetric coupled transmission
lines in...
EDLAN is a simple, inexpensive local area network suitable for
educational applications. In EDLAN, a number of personal computers are
connected through an RS-485 global bus which carries the data
transmission among the computers. CSMA/CD protocol is used to control
the access of the global bus. The communications are controlled...
A modeling technique for simulating the noise
performance of chopper-stabilized switched-capacitor
filters using SPICE2 is presented. A method for
selection of switched-capacitor network (SCN) stages
to be chopped and an op amp topology for low noise
applications are also outlined. Validity of the
modeling is verified by the close agreement...
With the development of converters and inverters, it
became possible to control the stator current of an
induction motor. The differential equations which describe
transient behavior of the induction motor are conveniently
expressed by transforming the stator and rotor variables to
d-q axes rotating at synchronous speed. The transient
behavior...
Compaction of a horizontal microprogram is an attempt to
exploit fully the parallelism permitted by a given algorithm and data
processing structure in order to produce a short microprogram. B oth
viewpoints of the problem: the local compaction viewpoint which
deals with compaction within a straight-line segment, or a basic...
In engineering, biology, ecology, medicine, economics and social
science, some processes are essentially bilinear, and some could be
approximated accurately by bilinear processes under certain conditions.
In this thesis the bilinear stochastic process and bilinear time series
are discussed.
Bilinear models essentially are nonlinear; the superposition rule
is not valid....
This thesis discusses the design and development of a
viable local area network (LAN) which supports both
communications and control applications. The emphasis was
to develop a practical and cost effective system which
offered high performance while utilizing low cost
components. System cost was kept low by utilizing a
twisted-pair...
In high voltage direct current(HVDC) systems
transmission technology, a.c. power is
converted(rectified) to d.c. power by means of a
controlled rectifier bridge. This d.c. power is then
transmitted through a d.c. link to another
converter(inverter) where it is converted back to a.c.
power by means of another controlled rectifier bridge....
An observability problem for both deterministic and stochastic
systems is studied here.
Deterministic observability is a determination of whether every
state of the system is connected to the observation mechanism and how
it is connected, if connected. On the other hand, stochastic
observability discusses the "tightness" of the connection in...
A DC-to-DC power converter was designed on the
basis of pulse-area modulation which is applied to a
series-resonant circuit with internal frequency of 10 Khz
The series-resonant circuit was placed directly in the
energy path which provides a means for the thyristors to
be naturally commutated.
The design was tested...
This thesis is concerned with the problem of achieving accurate recognition
rates for Cursive Script Recognition (CSR). Cursive Script Recognition is
difficult due to writer variations such as script formation and time non-linearities.
This research entailed analysis and implementation of a Cursive Script
word-level Recognition system using Dynamic Time Warping...
An analog signal processing technique allowing arbitrary step
response is presented. A transversal structure is used with
nonuniform contradirectional coupling to provide continuous tapping.
Sinusoidal and chirp responses are presented as examples implemented
using this nonuniformly coupled microstrip structure.
The purpose of this study was to design and to implement
a practical Ethernet Local Area Network (LAN)
board for the Macintosh II computer system. A survey
of the literature provided a general definition of
LANs, a reference model for network layers, specifications
for an Ethernet LAN, and information on...
Sorting is typically a compute intensive operation used in many
areas of industry. With improved technology, both in the VLSI and CAE
areas, we can afford to develop hardware based database computers to
move the work load off the main computer. In this thesis the
architecture of a VLSI parallel...
COLAN (Control Oriented Local Area Network ) is a
redesign of the Task-Master, a daisy-chain structure
distributed control system. COLAN is a simple bus structure
communication subnetwork intended for distributed control
applications. Low cost and simplicity are two main design
criteria. Point-to-point and broadcast communications are
possible. A packet switching...
Computers have made a great contribution to the
design process in various applications, such as design
analysis and simulation. A new technology called
Computer-aided design (CAD) has helped the designer to
design and build very intricate systems.
While most of CAD software is run on workstations or
microcomputers with one...
This thesis is composed of four parts: i) system
description, ii) model development, iii) parameter
estimation, and iv) validation. The natural system used
here is an aspect of the immune system, namely, the
distribution of recirculating lymphocytes in various
organs throughout the body. This distribution gains
importance because: i) it...
In order to analyze the accuracy of the navigation system LORAN-C, we have collected time - difference (TD) data from the U.S. west coast chain (9940) at a fixed receiver location (Corvallis, Oregon). The analysis of the TD data shows an unexpected high correlation between the TDs as well as...
Accurate Position Control is an important technique in
robotic engineering. The working environment of robotic
systems presents special requirements for position control.
The scope of this study is to explore the control algorithms
of a digital, hierarchical position control system. Detailed
analysis and simulation show that the system can be...
Existing pattern recognition and classification
algorithms in computer vision require vast amounts of
computations on input data. As a result, memory access time
is a critical parameter in system performance. Tremendous
parallelism in structure and algorithm is required for the
system to operate in real-time. A preprocessing structure
for qualitative...
An EMCON-D distributed process controller is evaluated
for control and monitoring of an experimental doubly-fed
machine system. A closed-loop control circuit is
implemented to operate the doubly-fed machine with
constant rotor current. A standard PID algorithm as well
as an algorithm tailored to the doubly-fed machine are
evaluated.
The thesis describes the preliminary studies on a
laboratory model of a magnetic elevator intended as part
of a system for circulating magnetic materials in chemical
reactors. A multiple coil laboratory model, controlled by
computer, was designed and constructed. Current measuring
transducers were used to monitor system performance and
study...
This dissertation demonstrates the utility of the
Instruction Set Processor Specification (ISPS) in a design
environment. Although ISPS supports a wide range of
applications in the areas of architecture evaluation and
certification, design automation, software generation and
fault simulation, the .emphasis in this dissertation is
focused on using it in...
The purpose of the thesis is to synthesize the major results of a continuous
research effort directed toward new applications of high speed sampling in general and Electrooptic Sampling in particular.
Equivalent time sampling of repetitive high speed signals continues to provide significant performance enhancements for present and future generations...
This dissertation introduces a new idea for frequency
domain deconvolution of speech signals. The idea is to
approximate a unit sample by a Gaussian pulse. The
deconvolution is performed by designing a glottal inverse
filter that will estimate the excitation of the vocal tract.
Then, the excitation will be used...
In the past two decades, a great amount of attention has been
paid to investigating the economic and safe operation of power
systems using modern mathematical techniques. The classic economic
dispatch problem, now often called the Optimal Power Flow problem,
has been formulated as a mathematical optimization problem and has...
This paper describes the design and implementation
of COLAN II, a control oriented local area network (LAN).
COLAN II employs a bus interconnection structure and
a token passing method to control the access to the bus.
Major emphasis of the work is on the system structure and
the software operating...
The drain current of InP MISPETs is often observed
to decrease as a function of time after the application of
a positive gate bias which involves an accumulation of
electrons in the channel. Various models have been
proposed for this drain current drift (DCD) phenomenon.
In this thesis, variable-temperature bias-stress...
The influence of weather on the long range radio navigation system Loran-C was investigated. The variables analyzed over a period of 255 days were: time differences (TDs), TD signal-to-noise ratios, TD standard deviations (measured at a fixed receiver location in Corvallis, Oregon), time interval numbers (TINOs) (measured at the transmitter...