This dissertation studies two different wireless microwave sensing applications in the subjects of environmental monitoring and biomedical devices. The environmental sensing application presents a design of novel wireless sensor node configurations. These nodes are intended to be used specifically in a built environment of railroad track ballast for its health...
Typical power outputs of commercially available diode lasers are on the
order of 5 milliwatts. This thesis discusses the growth, processing and
fabrication of high power (lOO's of milliwatts) diode lasers. Devices were
grown by Molecular Beam Epitaxy (MBE) and by Metal Organic Chemical
Vapor Deposition (MOCVD). The MOCVD diode...
To protect the environment and save human lives, the detection of various hazardous toxins of biological or chemical origin has been a major challenge to the researchers at Oregon State University. Living fish cells can indicate the presence of a wide range of toxins by reactions such as changing color...
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...
The purpose of this thesis is to apply the wavelet transform WT to
multiresolution structures for analyzing the information content of images based on
multiresolution signal decomposition of the wavelet representation. The advantage
of the wavelet transform is the fact that it uses different building blocks than the
Fourier's sines...
The awareness of electric power quality has increased over the past decade as electronic equipment
has become more susceptible to power disturbances. The most disruptive power disturbances are voltage
sags and momentary interruptions and their effect on adjustable speed drives (ASDs) is studied in this
thesis.
Several solutions have been...
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...
Adjustable Speed Drive (ASD) systems are widely used in industry to effectively improve process efficiency and control. Typically, an ASD system consists of a motor with its speed controlled by a power electronics converter via varying the amplitude and frequency of the input voltage. However, several abnormal insulation failures of...
A new structure for the implementation of bit/serial adaptive IIR filter is
presented. The bit level system consists of gated full adders for the arithmetic
unit and data latches for the data path. This approach allows recursive
operation of the IIR filter to be implemented without any global
interconnections, minimal...
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...
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 Brushless Doubly Fed Machine (BDFM) is receiving attention as a candidate for use in adjustable speed drives (ASDs) and variable speed generators (VSGs). With a large percentage of a drive or generator system's cost due to power electronics content, considerable research has been conducted to find drives in which...
The major limiting factor of DRAM access time is the low transconductance of the
MOSFET's which have only limited current drive capability. The bipolar junction
transistor(BJT) has a collector current amplification factor, β, times base current and is
limited mostly by the willingness to supply this base current. This collector...
The low thermal conductivity of gallium arsenide compared to silicon
results in self-heating effects in GaAs MESFETs that limit the electrical
performance of such devices for high power applications. To date, analytical
thermal models of self heating in GaAs MESFETs are based on the assumption
of a uniformly heated channel....
Turbo codes have been used successfully for error correction in digital communications, however, their application to wireless mobile communications is still a fresh research topic. The objective of this thesis is to present a new solution that involves the usage of turbo codes, spatial diversity, and orthogonal complementary codes in...
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...
While the performance gap between microprocessors and main memory is ever increasing each year, cache memory has been a bridge to alleviate this discrepancy. In this thesis proposal, we introduce three techniques to tolerate this processor and memory speed imbalance. First, we propose the bloom filter scheme to identify which...
A numerical technique to compute the time domain response of multiconductor lossy
uniform and nonuniform lines terminated in general nonlinear elements is presented. The
technique is based on the generalized method of characteristics. The method transforms the
original system of transmission line equations into a system of ordinary differential
equations....