At frequencies exceeding 1-2 GHz, the substrate network models used in substrate coupling simulation must account for the reactive nature of the substrate. Unlike at low frequencies, where the purely resistive substrate models can be validated through DC resistance measurements, these high-frequency models, comprising reactive components, must be validated through...
The detection of motor faults at their incipient stage is of prime importance to any industrial plant. The introduction of adjustable speed drives has improved the control and the efficiency of induction motors, however, this has changed the nature of motor faults and how they can be detected.
Current signature...
Spacecrafts experience radiation in the course of their operation
and all electronic equipment on board these spacecrafts has to
be designed to withstand the effects of this radiation.
This thesis describes the effects of total ionization dose (TID)
and single event transients (SET) in phase-locked loops - an
important circuit...
Circuits operating outside the earth’s atmosphere are more vulnerable to cosmic radiation and require special design consideration. The purpose of this work is to explore methods of mitigating the effect of radiation in phase locked loop (PLL) circuits. Several voltage controlled oscillators (VCOs) and two complete PLLs are designed and...
The design of a 10-bit pipelined charge redistribution DAC employing MOSCAPs biased in their accumulation mode is presented in this thesis. A switched capacitor filter and output buffer have also been designed for the system. The effect of MOSCAP nonlinearity on the performance of the pipelined charge redistribution DAC has...
Digital phase-locked loops (PLLs) have been receiving increasing attention recently due to their ease of integration, scalability and performance comparable to their analog counterparts. In digital PLLs, increased resolution in time-to-digital conversion is desirable for improved noise performance. This work describes the design and simulation of a stochastic time-to-digital converter...
End-user programmers, because they are human, make mistakes. However, past research has not considered how visual end-user debugging devices could be designed to ameliorate the effects of mistakes. This paper empirically examines oracle mistakes mistakes users make about which values are right and which are wrong to reveal differences in...
Previous research has revealed gender differences that impact females’ willingness to adopt software features in end users’ programming environments. Since these features have separately been shown to help end users problem solve, it is important to female end users’ productivity that we find ways to make these features more acceptable...
A large number of sequential decision-making problems in uncertain environments
can be modeled as Markov Decision Processes (MDPs). In such settings, an agent
can observe at each time step the state of the environment and then executes an
action, causing a stochastic transition to a new state of the environment...
Ultra-wideband (UWB) radio is the transmission of data using an extremely wide bandwidth and very low power spectral density. In this thesis, the mereits and challenges of UWB architectures versus conventional narrowband architectures will be compared. Pulsed UWB systems can be implemented with very simple architectures. These advantages make UWB...
Ferrites have been used for various high frequency applications as bulk
materials. These applications, however, are limited to large dimension devices. In
this thesis, thin film ferrites were deposited from a low temperature solution-based
deposition process that is suitable for micro-scale high frequency applications. The
low temperature nature of this...
With the ever-increasing demand for portable devices used in applications
such as wireless communication, mobile computing, consumer electronics, etc.,
the scaling of the CMOS process to deep submicron dimensions becomes more
important to achieve low-cost, low-power and high-performance digital systems.
However, this downscaling also requires similar shrinking of the supply...
A discrete trap model is developed and employed for elucidation of thin-film transistor (TFT) device physics trends. An attractive feature of this model is that only two model parameters are required, the trap energy depth, E[subscript T], and the trap density, N[subscript T]. The most relevant trends occur when E[subscript...
Digital-to-analog converters (DACs) suffer from static and dynamic nonlinearity problems, which degrade their accuracy and performance. Mismatch errors in the analog components restrict the maximum achievable linearity.
This thesis presents various techniques for correcting these errors. It describes a correction process for the nonlinear behavior of DACs, on three different...
Recently, continuous-time ΔΣ modulators are appearing increasingly often in both the literature and the marketplace due to their features of inherent antialiasing and relaxed requirements for opamp and so on. However, several nonideal factors such as clock jitter, excess loop delay, inter-symbol interference and so on, degrade the SNR performance...
This thesis presents a Z-parameter based model to predict the substratenoise coupling between two contacts in a heavily doped substrate for frequenciesless than 2 GHz. The empirical model is scalable with contact size and spacingsbetween the contacts and model parameters can be readily extracted from simu-lated or measured data. The...
Commonly proposed ocean wave energy converters (OWEC) use inefficient and maintenance demanding intermediate hydraulic and pneumatic systems. We propose a novel rotary direct-drive OWEC that eliminates these intermediate stages. The new device employs a contactless force transmission system (CFTS) comprising a “piston” and a “cylinder” and a ball screw to...
There is a large and growing market for portable consumer audio products
with very small size. As the size of these products is reduced, the area occupied
by batteries becomes significant and hence limits the number of batteries to one.
In order to build such small products, high levels of...
Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), a shade intolerant species, and western hemlock (Tsuga heterophylla (Raf.) Sarg.), a shade tolerant species, were compared to learn more about the temporal pattern of release from suppression in both species, whether hydraulic architecture or photosynthetic capacity constrain release and how wood functional properties change...
Paclitaxel is a very important anticancer drug commonly called Taxol®.
We know from previous work (Hoffman, et al., 1998) that Taxol exists in filbert, Corylus avellana L. material. Quantification of Taxol in filbert plant material is painstaking and hitherto was accomplished by rapidly processing single batches in a complicated procedure...
Our objectives were to determine 1) the concentration of prostaglandin
F2α (PGF2α) in whole and extended bovine semen, 2) if concentrations of
prostaglandins in extended bovine semen are correlated to fertility, and 3) if PGF2α
administered at the time of artificial insemination would improve conception rate.
Concentration of PGF2α tended...
Regression calibration inference seeks to estimate regression models with measurement error in explanatory variables by replacing the mismeasured variable by its conditional expectation, given a surrogate variable, in an estimation procedure that would have been used if the true variable were available. This study examines the effect of the uncertainty...
The purpose of this thesis is to explore dependency speculation in Dynamic Simultaneous Multi-Threading (DSMT). DSMT is a microprocessor architecture which attempts to extract Thread Level Parallelism (TLP) from single-threaded programs at run-time. This is accomplished by running multiple iterations of program loops in parallel. The DSMT architecture was originally...
Functional programming is concerned with referential transparency, that is, given a certain function and its parameter, that the result will always be the same. However, it seems that this is violated in applications involving uncertainty, such as rolling a dice. This thesis defines the background of probabilistic programming and domain-specific...
Experiments were conducted to determine the influence of cultural management practices on weed growth in nursery containers. Experiments 1 and 2 evaluated the effects of dolomitic lime rate and application method on substrate pH, creeping woodsorrel (Oxalis corniculata L.) establishment in containers, and growth of azalea (Rhododendron ‘Rosebud’) and pieris...
The purpose of this study was to explore the phenomenon of community colleges creating pathways to degree completion in professional-technical programs by breaking degree programs into smaller portions, referred to as "chunks." The purpose or possible advantage of chunking was that it would improve the rate of degree completion among...
Continuously tunable diode laser sources coupled to single-mode fiber are useful sources for fiber Bragg grating (FBG) strain sensors. This paper describes the
development and fabrication of such a device. An introduction is given describing
applications of tunable lasers and some of the different methods of creating a tunable
diode...
Four aspects of factors influencing the accuracy of nondestructive chlorophyll (Chl) and nitrogen (N) measurement in fresh leaves were studied: (1) optimum wavelength (OW) identification; (2) indices development and evaluation; (3) influence of leaf properties; and (4) influence of meter parameters and sampling technique. Results were used to develop indices...
Fire is a major disturbance process in many forests. Long-term studies of the biogeochemical effects of fires, especially on soils, are very rare.
Consequently, long-term effects of fire on soils are often hypothesized from
short-term effects. In a chronosequence study, I studied 24 western Cascades
(Oregon) forest stands thought to...
This research was designed to broaden the understanding of how timber-harvest affects aquatic macroinvertebrates in perennial and intermittent headwater streams. This study compared emergent and benthic macroinvertebrate assemblages from 20 headwater streams in the central Oregon Coast Range that varied by harvest condition and flow duration. Through comparison of the...
Community colleges are experiencing a decline in state allocated funding. Traditionally, college administrators look for ways to cut expenditures and raise tuition and fees to make up for the shortfall. Using available land resources to generate a revenue stream may provide revenue for community colleges.
The purpose of this study...
Designing spectral efficient, high-speed wireless links that offer high quality-
of-service and range capability has been a critical research and engineering challenge. In this thesis, we mainly address the complexity and performance issues of
channel estimation and data detection in multiple-input multiple-output (MIMO)
orthogonal frequency division multiplexing (OFDM) systems over...
Island systems and species are susceptible to extinction because of their small population size and an ecological naiveté from an evolutionary past lacking strong competition and predation. For example, only one-fifth of the world’s bird species occur on islands, yet more than 90% of the avian extinctions witnessed during historic...
Previous research in South Fork Hinkle Creek suggested that coastal cutthroat trout exhibit an aggregated spatial pattern across multiple spatial scales. To evaluate the persistence of the observed abundance patterns and identify factors that affect those patterns, half-duplex passive integrated transponders (PIT-tags) were implanted in 320 coastal cutthroat trout (>...
Pinyon-juniper woodlands throughout the western U.S. have expanded rapidly following European settlement during the late 19th century. In central and eastern Oregon, western juniper (Juniperus occidentalis var. occidentalis Hook.) encroachment has been previously documented in the sagebrush steppe and upper elevation aspen communities. While these vegetation changes and dynamics have...
Habitat loss causes a reduction in available resources for wildlife, alters the configuration of remaining habitat, and may isolate wildlife populations. White-breasted nuthatches (Sitta carolinensis) are experiencing long-term population declines in the Willamette Valley of Oregon, where they are historically associated with oak woodlands. As secondary cavity-nesters, white-breasted nuthatches may...
Mycobacterium avium is an intracellular pathogen that is associated with disseminated
infection, especially in patients with acquired immunodeficiency syndrome (AIDS). It
appears that patients with AIDS acquire M. avium mostly through the intestinal tract,
and that bacteria enter the intestinal wall at the terminal ileum. Previous studies have
found that...
This thesis presents a comparison of time-domain and frequency-domain algorithms for phase noise calculation in oscillators. Floquet theory provides the mathematical foundation for these calculations and the numerical methods employ perturbation projection vectors (PPVs). The PPVs are an estimate of an oscillator's sensitivity to noise.
The in-house circuit simulator SPICE3...
Canopy gap formation is a major factor contributing to maintenance of overstory species diversity and stand structure in forests and may be integral to development of understory shrub and herb layers as well. Acknowledgement of gap formation as a fundamental feature of natural forests has led to consideration of gaps...
We isolated and characterized the expression of two genes from Populus
trichocarpa that are homologous to the TERMINAL FLOWER 1 (TFL1) gene from
the model annual plant Arabidopsis. In Arabidopsis, overexpression of the TFL1
gene extends the vegetative growth phase, and the homozygous mutant tfl1 allele
causes early flowering and...
Biological agents and their products commonly cause foodborne illnesses. In the United States it is estimated that there are over 76 million cases of foodborne illnesses each year, resulting in an economic loss of approximately $40 billion. These high figures demonstrate the need for bioassays that display a rapid and...
For the first objective of this thesis, we attempt to understand the role of water flow and directionality in determining steelhead (Oncorhynchus mykiss) and spring/summer and fall Chinook (O. tschawytscha) migration patterns within the Columbia River Estuary and plume by integrating recent advances in biotelemetry and environmental observation and forecasting...
Traditionally linear actuator applications are addressed by the use of hydraulic systems. The high maintenance cost and poor reliability will always be the most critical problem in the real applications. Benefited from both the high mechanical advantage of the roll screw and the simple structure of the switched reluctance motor,...
Recent studies of headwater streams have demonstrated their importance to overall watershed biodiversity, nutrient cycling, and energy flux. However, little attention has been paid to long-term effects of forest harvest on macroinvertebrate communities in headwater streams. This study investigated headwater stream macroinvertebrate communities in the H.J. Andrews Experimental Forest, Oregon,...
This thesis is an investigation of the natural products deriving from marine algae and cyanobacteria and has resulted in the discovery of eleven new secondary metabolites. The structure elucidations of these new molecules were performed using a variety of spectroscopic techniques. Four new macrolides were isolated and characterized from the...
Riparian zone vegetation can influence terrestrial and aquatic food webs through variations in the amounts, timing, and nutritional content of leaf and other litter inputs. Differences in vegetation composition and density, as well as riparian topography, may modulate the strength and quality of these inputs. Changes in inputs to small...
This research addresses sample process variance estimation on continuous domains and for non-probability samples in particular. The motivation for the research is a scenario in which a program has collected non-probability samples for which there is interest in characterizing how much an extrapolation to the domain would vary given similarly...
This dissertation concentrates on the controlling factors on the instability of the Laurentide Ice Sheet (LIS) and their effects on abrupt climate change. Northern Hemisphere climate fluctuated abruptly during the last deglaciation possibly related to variability in Atlantic meridional overturning circulation (AMOC) and reduced aerial extent of the LIS. Reductions...
In recent years, there has been growing interest in both industry and academia to use continuous-time (CT) Δ-Σ A/D converters for wideband wireless and wireline communication applications.
So far no reported CT Δ-Σ A/D modulator achieves 14-bit or higher dynamic range (DR) with more than 2MHz signal bandwidth (equivalently 4MS/s)....
The objectives of this project were to determine the effects of harvest maturity, packaging, and storage conditions on subsequent fruit quality of Actinidia arguta ‘Ananasnaya’ and to investigate the use of edible coatings to improve fruit quality and storage life. The influences of harvest maturity (6.0, 8.7, 9.1, and 15.1%...