This qualitative study describes and interprets the interactions of participants in a
community college writing class delivered by computer-mediated communication
(CMC). The class represented a best practice model of learner-centered instruction in a
CMC class. The description and the discussion are framed by five aspects of CMC
instruction: (1) context;...
Two studies which were similar in protocol were conducted.
Following a preliminary baseline period of 7 days, in which the
subjects consumed their self-chosen diets, they received 3 eggs daily
for 4 weeks. Depending upon the changes in plasma cholesterol in
response to 3 eggs daily, the subjects in studies...
This study investigated the attitudes of mental health counselors toward persons
with Acquired Immunodeficiency Syndrome (AIDS). Three hundred and fifty-eight
members of the American Mental Health Counselors Association were mailed a survey
packet including an Attitude Towards AIDS Victims scale and an additional two
questions assessing comfort with clients with...
The purpose of this study was to discern unpredicted, non-linear patterns that may emerge in complex instructional systems design projects. A secondary purpose was to determine how existing models could be redesigned to accommodate emerging factors. The following questions focused the inquiry:
1. In what ways does the actual ISD...
The phytohormones auxin and cytokinin control plant development through a complex network of interactions which include synergistic, additive, and opposite effects whose mechanisms are unknown. The auxin-insensitive diageotropica (dgt) mutant provided a tool to dissect the relationship between auxin- and cytokinin-induced responses in tomato. Morphological, physiological, and molecular data support...
The plant hormone auxin regulates many aspects of plant growth and
development. At the cellular level, auxin can stimulate cell division, cell elongation, and
cell differentiation. Little is known about the molecular mechanisms that mediate auxin
action at this level, although changes in gene expression have been implicated in each...
The thesis begins with an introduction to signal transduction
and an analysis of current understanding of plant signal
transduction. There are similarities between plants and animals,
but also key differences, including lack of protein kinase C and of a
cAMP signaling pathway in plants, and presence in plants of
calcium...
The auxin-resistant diageotropica (dgt) mutant of tomato (Lycopersicon esculentum Mill.) has a pleiotropic phenotype including a lack of lateral roots and reduced gravitropic response, apical dominance, vascular development, and fruit growth. The dgt mutation reduces the auxin sensitivity of only a subset of auxin responses while levels, metabolism, and transport...
Plant growth, development, and environmental responsiveness are
dependent on hormone-induced gene expression. This dissertation reports
multiple interactions between the plant hormones auxin and ethylene and
investigates their contribution to the gravitropic response, elongation
growth, adventitious root formation, callus and tracheary element initiation
and growth, and flower development.
Four mutants of...
Plant hormones regulate progression through the different phases of plant development in response to endogenous and environmental cues. Gene expression studies, as well as genetic and molecular analysis of mutants with altered hormonal responses, are two common approaches to elucidate hormone response pathways. This dissertation compares ovary and fruit development...
The diageotropica (dgt) mutation has been proposed to affect either auxin
perception or responsiveness in tomato plants. Auxins and cytokinins are plant
growth regulators known to interact with each other via a variety of mechanisms.
Here, we report the interactions of auxins and cytokinins in VFN8 wild-type and
dgt mutant...
Auxin and ethylene regulate many important aspects of plant growth and development and are
essential to the plants survival. They help regulate such diverse processes as cell elongation,
growth of adventitious roots, fruit growth, germination, and a variety of other processes. Few
studies have examined how the hormones auxin and...
The exponential rate of advances in modern communication devices in the last several years have brought us higher levels of functionality and performance as well as reductions in physical size and power consumption. To continue this rate of advancement, next generation systems require wider bandwidth and higher resolution ADCs. Additionally,...
Two aspects of ADC system performance are addressed in this work. First, the combination of the ADC and its associated reference are co-designed for an energy constrained remote sensing system. Second, sampling linearity is mathematically analyzed as a function of frequency to provide enhanced understanding into an ADC's requisite sampling...
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)....
There is a significant need in recent mobile communication and wireless broadband
systems for high-performance analog-to-digital converters (ADCs) that have wide
bandwidth (BW>5-MHz) and high data rate (>100-Mbps). A delta-sigma ADC is
recognized as a power-efficient ADC architecture when high resolution (>12-b) is
required. This is due to several advantages...
What are the most effective ways to improve the engineering curriculum? Improvements should result in increased student retention, undergraduates who are more industry-ready and graduates who are better prepared to be leaders. Current research suggests that the best predictor of persistence is a person’s self-efficacy. The focus of this thesis...
The ability to accurately locate people and objects indoors will enable opportunities for control and automation of indoor environments. Current indoor localization solutions require dedicated hardware which must be custom tailored to each application. There are large technological, societal, and economic benefits in developing a more general purpose system that...
Conversion of exogenous cis-zeatin to trans-zeatin in immature seeds of
Phaseolus vulgaris L. led to the isolation of a cis-trans isomerase from the endosperm.
The enzyme was purified over 2000-fold by chromatography on a series of FPLC
(anion exchange, gel filtration, and hydrophobic interaction) and Concanavalin A
columns. Non-enzymatic isomerization...
A biosystematic investigation of Cryptogramma section
Cryptogramma in western North America has been directed towards
resolution of two separate taxonomic questions.
Results of this research support the hypothesis that a
previously undescribed diploid (2n = 30 II) taxon, C. cascadensis, is
present along with the common and widespread C. acrostichoides....
Wheat breeders must effectively maintain and manage existing genetic diversity in order to continue the development of superior genotypes. It is therefore fundamental that the genetic relationships and diversity within the germplasm pools be thoroughly characterized and understood. Recently, DNA-based markers have provided powerful tools for genetic diversity analysis. This...
In this dissertation, a new Δ∑ A/D converter is presented that is ideally suited for communication applications. It is based on a single-loop single-stage structure, which can realize a high maximum out-of-band quantization noise gain while maintaining stable operation and thus achieve 14-bit resolution at 8 times oversampling. A fifth-order...
At frequencies exceeding 1-2 GHz, the reactive nature of a silicon substrate must be accounted in the substrate network models used in substrate coupling simulation. High-frequency substrate models, containing reactive components, must be validated through high-frequency network analyzer measurements. Prior fabricated test fixtures have been modified to enable high-frequency (up...
A computationally efficient and accurate substrate noise coupling model for multiple contacts in heavily doped CMOS processes is presented and validated with simulations and experimental data. The model is based on Z parameters that are scalable with contact separation and size. This results in fast extraction of substrate resistances for...
This thesis presents the contributions to substrate noise due to supply coupling and the effect of pin parasitics on the substrate noise generated by digital circuits. Various sources of substrate noise and their effect on analog circuits sharing the same substrate are discussed. A simulation approach to isolate the various...
A variable gain, high linearity, low power baseband filter for WLAN applications is implemented in a 1.5 V 3 V 0.15 μm CMOS process. This fourth-order low-pass filter, which is introduced in the transmit channel as a reconstruction filter between the D/A converter and the mixer, has a measured cut-off...
This dissertation focuses on the analysis, design, and application of inductor-capacitor (LC) oscillators for wireless sensor networks (WSNs).
First an analysis and design optimization approach for enhanced swing, low power CMOS LC oscillators is presented. A phasor based analysis is used for determining the amplitude and phase noise of these...
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...
This thesis presents a systematic top-down methodology for simulating a phase-locked loop using a macro model in Verilog-A. The macromodel has been used to evaluate the jitter due to supply noise, thermal noise, and ground bounce. The noise simulation with the behavioral model is roughly 310 times faster (best case)...
A scalable macromodel for substrate noise coupling in lightly doped substrates with and without a buried layer has been developed. This model is based on Z-parameters and is scalable with contact size and separation. This model requires process dependent parameters that can be extracted easily from a small number of...
The parasitic components of MOS switches at high speeds affect the linearity and resolution of CMOS sample and hold circuits. CCD-based circuit design can offer good performance at high speeds. This thesis presents the design of sample and hold circuits using charge-coupled device structures in a standard CMOS process. Three...
For today’s ubiquitous portable devices, innovative integrated circuits with high performance
yet very low power are necessary. As these devices are used to communicate and sense real world signals in the environment, analog-to-digital converters (ADC) and systems are the key interface circuits needed to digitize the sensed information and they...
Noise-shaping multibit quantizers in a ΔΣ modulator offer extra orders of noise shaping without increasing the loop-filter order and without compromising the stability of the modulator. This dissertation presents two new architectures for improving the overall performance of continuous-time ΔΣ modulators using noise-shaped quantizers.
The first modulator architecture is motivated...
A differential current-mode track-and-hold (T/H) amplifier is used to sample an analog input signal. A new closed-loop current-mode architecture has been developed that overcomes the stability problems associated with closed-loop architectures. The T/H circuit has been fabricated in a 0.35-μm quad-metal, double-poly CMOS process. The measured total harmonic distortion (THD)...
As the demand for real-time information in engineering and health care systems keeps increasing, the need for wireless sensor nodes is also continuously increasing. As a result, the cost and effort involved in installing and maintaining batteries to power the numerous sensor nodes is growing exponentially. Providing a cost effective...
A Z-parameter based macromodel for characterizing the substrate noise coupling in a lightly doped substrate at low frequencies has been developed. The model is scalable with contact geometries and separation. The cross-coupling impedance between two contacts is modeled using an improved geometric mean distance formulation. This approach obviates the need...
Analysis of substrate noise coupling has been performed for a 0.18¹m lightly doped silicon germanium BiCMOS process. Techniques to minimize noise coupling in the chip and board design are presented, as well as methods for accurate modeling for substrate noise coupling simulations. Measurements from a test chip were taken to...
A new method is presented to compress switching information in large digital circuits. This is combined with an efficient approach of generating the noise signatures of cells in a digital library that results in an accurate and efficient approach for estimating the noise generated in digital circuits. This method provides...
The substrate noise injected by a stepped buffer circuit into two single-ended 1.5GHz low noise amplifiers is examined for a heavily doped 0.25µm CMOS process. The difference in the LNA noise rejection is characterized as a function of the size and placement of substrate contacts. The use of a resistive...
An automated method, requiring the fabrication of a small set of test structures, efficiently extracts the coefficients of Z-parameter based macromodels. The extraction approach has been validated for both heavily and lightly doped substrates and can be applied to a variety of technologies. After the parameters of a macromodel have...
Harvesting energy from the environment for powering micro-power devices have been increasing in popularity. These types of devices can be used in embedded applications or in sensor networks where battery replacement is impractical. In this dissertation, different methods of energy harvesting from the environment are explored as alternative sources of...
Portable, high power efficiency communication devices is a growing market in the semiconductor industry. Analog-to-digital converters (ADC) are key interface that are used to digitize the sensed information. Recently, digital techniques have been proposed to improve analog building block power efficiency in sub-micron technologies. This research focuses on mixed signal...
A fully integrated CMOS GPS receiver RF front end optimized for low power operation is presented. The system operates with a supply voltage down to 250 mV. A prototype has been fabricated in a 0.13μm CMOS process and includes a low voltage LNA, quadrature oscillators, and quadrature mixers. It exhibits...
In 2000 the Electrical and Computer Engineering department at Oregon State University began a new and innovative program named TekBots[superscript TM]. This program was created to solve the problems of students in existing undergraduate engineering education not having sufficient skill when graduating in six program educational objectives; Depth, Breadth, Professionalism,...
In April of 1997 it was pointed out at an NSF Engineering Education Innovators conference that “… education appears to ignore the need for connections and for integration – which should be at the core of an engineering education.” In order to solve this problem a group named ‘TekBotsTM’ was...
Analysis and design optimization of enhanced swing, low power CMOS LC oscillators is presented. A phasor analysis based approach for determining the amplitude and phase noise of these oscillators is used. MOSFET operation in cut-off, linear and saturation regions is included. The calculated steady state output amplitude and phase noise...
Improved recovery of cryopreserved meristems and calli from in
vitro currant (Ribes aureum Pursh and R. ciliatum Humb. & Bonpl.) plants
was obtained by two-hour pretreatment with sucrose, proline, abscisic
acid-responsive protein (RABP), and bovine serum albumin (BSA)
solutions. Meristems and calli cold-acclimatized for one week were
immersed in pretreatment...
Calcium carbonate percentages at five Ceara Rise sites were estimated at 1- to 2-k.y. intervals over the past 5 m.y., using
reflectance spectroscopy and magnetic susceptibility proxies. From these estimates and detailed correlations between sites, gradients
of calcite and terrigenous sediment accumulation rates in a depth transect of sites reveal...
Attracting, educating and retaining new engineering students is a challenge. The creative aspirations and "can do" attitude spawned by the space race, Heathkits, and homemade crystal radios have been replaced with the passive satisfaction of video games, cell phones and throwaway electronic appliances. At Oregon State University we have made...
The self-help literature is full of texts on both self-compassion and postpartum depression. However, there has been minimal scientific exploration of the literature on these topics. As such, mental health researchers and practitioners have little sense of the psycholinguistic discourse contained in this literature. This study aimed to fill this...
An ultra low power crystal oscillator that provides a frequency reference for battery
powered timekeeping applications is presented. An amplitude control circuit is employed to ensure that minimum current is consumed. A subthreshold voltage regulator provides a supply voltage for the oscillator with minimum current consumption. The oscillator and regulator...
This thesis presents distinctly different methods of accurately predicting phase noise and absolute jitter in ring oscillators. The phase noise prediction methods are the commercially available SpectreRF and isf_tool, a simulator developed in this work from the Hajimiri and Lee theory of phase noise. Absolute jitter due to deterministic supply...
This thesis presents a design-oriented model for lightly doped CMOS substrates. The model predicts the substrate noise coupling between noisy digital and sensitive analog blocks in the early stages of the design. The model scales with the size and separation of these blocks and it is validated with device simulations...
Three types of low noise amplifiers operating at 2.4GHz were designed. They are the commonly used single-ended and differential amplifiers as well as a new quasi-differential amplifier. The substrate noise injected into these amplifiers is examined for both heavily and lightly doped CMOS substrates. For the single-ended amplifier the noise...
A methodology for rapid estimation of substrate noise generated by digital circuitry in mixed-signal circuits is presented. This methodology is incorporated into the Silencer! framework, and also provides for future improvements including pre-layout noise estimation. Measurements of a test chip fabricated in the TSMC o.25[mu]m heavily doped logic process validate...
An enhanced swing differential Colpitts VCO (ESDC-VCO) dramatically improves
the swing of a Colpitts VCO by allowing the signal to swing below ground and above the
supply voltage. Fabricated in a 1P8M 0.13 um CMOS process, the ESDC-VCO operates
at 4.9GHz with a 0.475-V supply and consumes 2.7mW. The measured...
In wireless sensor network applications, low-power operation of the wireless receiver is critical. To address this need an ultra-low power Binary Frequency Shift Keying (BFSK) receiver using the super-regenerative architecture is developed.
A prototype receiver is built and tested for operation in the 900 MHz ISM band. Lab measurements show...
Wireless sensor networks are becoming important in several monitoring and sensing applications. Ultra low power consumption in the sensor nodes is important for extending the battery life of the nodes. In this dissertation, two low power BFSK receiver architectures are proposed and verified with prototype implementations in silicion.
A 2.4...
This thesis presents a low-energy application specific digital controller for a battery-free 2.4 GHz wireless sensor network (WSN) node. The digital controller has been designed and fabricated in a standard 0.13 μm CMOS and implements a simple protocol for WSNs. Techniques such as supply voltage reduction and power gating have...
As the number of autonomous data collection applications keep increasing, the demand for wireless sensor networks (WSNs) has seen explosive growth. In this dissertation, an ultra-low-energy WSN transmitter is developed to reduce the energy consumption of sensor nodes in WSNs. With an ultra-low-energy transceiver, it is possible to eliminate the...
An analysis of substrate noise coupling in mixed-signal circuits has been performed in the TSMC 0.25 [mu]m lightly doped and heavily doped CMOS processes. Methods to minimize noise coupling in both the chip design and board design phases are presented along with techniques for accurate circuit simulation of noise coupling....
This thesis examines substrate noise coupling for NMOS transistors in heavily doped substrates. The study begins with the analysis of an NMOS transistor switching noise in a digital inverter at the device level. A resistive substrate network for the NMOS transistor is proposed and verified. Coupling between N+- P+ contacts...
This thesis presents Silencer!, a fully automated, schematic-driven tool for substrate noise coupling simulation and analysis. It has been integrated in the CADENCE DFII environment and seamlessly enables substrate coupling analysis in a standard mixed-signal design flow. Silencer! aids IC designers in the analysis of substrate noise coupling at different...
This thesis presents a low power DC-DC converter suitable for harvesting energy from high impedance thermoelectric generators (TEGs) for the use in body powered electronics. The chip has been fabricated in a 130nm CMOS technology. To meet the power demands of body powered networks, a novel dual-path architecture capable of...
A fully integrated CMOS latched comparator is presented for use as a wake-up circuit that is attached to an RF energy harvester in a battery free wireless sensor network. The system consumes less than 36nA static current at 20°C and dissipates 2pJ of energy per conversion. The comparator comprises of...
Low energy design techniques for digital circuits are examined to determine their suitability for use in a digital logic controller for wireless sensor network nodes. Transistor level simulations are used to evaluate the techniques and those demonstrating an energy reduction are used to implement a digital logic controller. The digital...
Conventional Delta-Sigma analog-to-digital converters (ADCs) utilize operational transconductance amplifiers (OTAs) in their loop filter implementation followed by multi-bit voltage domain quantizers. As CMOS integrated circuit technology scales to smaller geometries, the minimum transistor length and the intrinsic gain of the transistors decrease. Moreover, with process scaling the voltage headroom decreases...
Delay insensitive asynchronous circuitry provides significant advantages with
respect to substrate noise due to localized switching. The differences between the
substrate noise from NULL Convention Logic (NCL) and traditional Clocked
Boolean Logic (CBL) are described and analyzed based on measured results. A test chip fabricated in the TSMC 0.25 um...
Modern sensor network applications are often implemented wirelessly in order to lessen installation costs and reduce deployment times. Unfortunately, these wireless sensor network (WSN) nodes must often rely on batteries or energy harvesting techniques in order to sustain their operation and supply the power needed to maintain communication within the...
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...
Analog-to-digital converters (ADCs) are the key building block for sensor applications, such as wireless communications and digital electronics. These applications require ADCs to have medium to high accuracy (normally from 10-14 bits) and relatively low signal bandwidth (ranging from 100Hz-150kHz). Since these applications are often powered by batteries, high power...
The design of mobile wireless devices has always focused on reducing power, area, and cost. This dissertation proposes two techniques that are leveraged to save power and area and therefore cost. The first techniques reduces the noise in the receiver and results in a relaxed power requirement. The second technique...
This thesis presents an automated methodology to calibrate the substrate profile for accurate prediction of substrate parasitics using Green's function based extractors. The technique requires fabrication of only a few test structures and results in an accurate three layered approximation of a heavily doped epitaxial silicon substrate. The obtained substrate...
Efficient methods for simulating the substrate noise generated by complex synchronous and asynchronous digital logic circuits are presented. By simulating digital logic at the gate level, and precharacterizing the gates, the substrate noise generation can be predicted and used in a transistor level simulation of the sensitive analog blocks. This...
A new enhanced swing class-D VCO which operates from a supply voltage as low as 300 mV is presented. The architectural advantages are described along with an analysis for the oscillation frequency. Prototype differential and quadrature variants of the proposed VCO have been implemented in a 65 nm RF CMOS...
This thesis focuses on two aspects of oxide-based thin-film transistors (TFTs), contact resistance and instability assessment.
First, determination of the contact resistance of indium tin oxide (ITO) on two wide-band gap semiconductors, zinc oxide (ZnO) and indium gallium oxide (IGO), is attempted and the effects of contact resistance on device...
A method for improving performance/watt of an embedded single-instruction multiple-data (SIMD) architecture using application-guided a priori scheduling of hardware resources is presented. A multi-core architectural simulator is adopted that accurately estimates power, performance, and utilization of various processor components (logic, interconnect and memory). A greedy search is then performed on...
Victoria blight of oats is caused by the fungus Cochhobolus victoriae. This fungus is pathogenic due to its ability to produce the host-selective toxin victorin. Previously, a 100-kD protein that binds victorin in vivo only in susceptible genotypes was identified as
the P protein of the glycine decarboxylase complex (GDC)....
Protein kinases are an abundant class of enzymes which play important roles in numerous signal transduction systems. Arabidopsis TOUSLED kinase is a serine/threonine kinase which is essential for cell-cell communication within the shoot meristem. TOUSLED is encoded by a single gene in Arabidopsis. Recessive mutants in this gene show mild...
Coproporphyrinogen III oxidase (CPX) is an enzyme involved in the biosynthesis
of tetrapyrroles, catalyzing the oxidative decarboxylation of coproporphyrinogen III to
protoporphyrinogen IX. In bacteria and yeast this enzyme is cytosolic, in animals it is
mitochondrial, and in each it functions to produce heme. However, in all plants
investigated, the...
Calow (1983) realized that differences between parasites and their free-living
relatives can be explained by the differences in nutrient richness. I
propose a model that is based on Calow's idea which identifies the relative
position of different trophic strategies (e.g. predation, grazing, parasitism and
others) based on (1) the differences...
In this thesis, the performance degradation of a phase-locked loop due to substrate noise is examined. A new analytical equivalent circuit model for substrate noise coupling is derived for a heavily doped silicon substrate. The model has been validated with measured data from a 0.35 μm CMOS process. Since the...
In the Northwest Great Basin, aspen (Populus tremuloides) communities uniquely contribute to the biodiversity of a semi-arid, sagebrush-dominated landscape. In this same region, western juniper (Juniperus occidentalis) is encroaching into aspen stands. This study determined the timing, extent, and some of the effects of this expansion. Aspen stands below 2,133...
Llamas (Lama glama) appear to have predisposing anatomical features for developing
otitis media such as a long and narrow external acoustic meatus and a trabecular
tympanic bulla. However, there is limited information available about the morphology of
the ear in this species. The aim of this study was to evaluate...
Alternating temperature (22°C / -1°C) pretreatments were effective for
increasing cold hardiness and recovery of cryopreserved meristems. Combining low
temperature pretreatment with abscisic acid (ABA) or sucrose treatments reduced the
time required for optimal cold hardiness of meristems. Desiccation tolerance was
directly correlated with increased cold hardiness and recovery of...
Published February 1987. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
For good reason, suicide is of growing concern across the nation; rates continue to increase annually in the United States. Accurate assessment remains an obstacle to effective treatment for individuals who are suicidal. Without proper screening, a client cannot get a referral to see a specialist and therefore cannot receive...
Peroxisome proliferator-activated receptors (PPARs) are members of a
large group of ligand-regulated transcription factors that includes nuclear
receptors for steroid and thyroid hormones, retinoids and vitamin D₃.
Synthetic fibrates and thiazolidinediones that bind to and activate PPARs are
used efficaciously in humans to remedy hypertriglyceridemia and non-insulin
dependent diabetes mellitus,...
Maize defective kernel (dek) mutants identify genes necessary for the
successful passage of embryos through the embryogenic and maturation
phases of embryo development. The goal of this thesis was to characterize the
developmental potential of three dek mutants that appeared to be
morphologically blocked prior to the maturation phase of...
Experiments were performed to assess regulatory factors governing maize
embryo maturation and vivipary. Both visual and molecular markers of embryo
development were used to examine the roles of the hormones abscisic acid (ABA)
and gibberellins (GAs), as well as water stress in governing transit from early
embryogeny to maturation-phase development....