As Moore’s Law continues to give rise to ever shrinking channel lengths, circuits are becoming more digital and ever increasingly faster. Generating high frequency clocks in such scaled processes is becoming a tough challenge. Digital phase locked loops (DPLLs) are being explored as an alternative to conventional analog PLLs but...
The problem of footstep level resolution indoor path tracking and gait velocity
lacks a good solution. The current solutions are either prohibitively expensive [4],
extremely invasive to deploy [1], or too inaccurate to achieve the sub meter level
resolution required to track foot paths. By combining existing pedestrian dead
reckoning...
As the number of mobile devices accessing large-scale WLANs such as campus
and metropolitan area networks increases, the need for load balancing among the
cells becomes crucial. In addition, the network must also support some minimum
handoff tolerance defined by an application.
A number of load balancing techniques have been...
In this thesis, convergence of time inhomogeneous Markov chains is studied using an adiabatic approach. The adiabatic framework considers slowly changing systems and the adiabatic time quantifies the time required for the change such that the final state of the system is close to some equilibrium state. This approach is...
High speed serial links are critical components for addressing the growing demand for I/O bandwidth in next-generation computing applications, such as many-core systems, backplane and optical data communications. Due to continued process scaling and circuit innovations, today's CMOS serial link transceivers can achieve tens of Gb/s per pin. However, most...
The quality of a digital image pipeline relies greatly on its color reproduction which should at a minimum handle the color constancy, and the final judgment of the excellence of the pipeline is made through subjective observations by humans.
This dissertation addresses a few topics surrounding the color processing of...
Nanolaminate dielectrics combine two or more insulating materials in a many-layered film. These structures can be made to significantly outperform films composed of a single one of their constituent materials by adjusting the composition ratio, arrangement, and size of the component layers. In this work, atomic layer deposition (ALD) is...
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...
Solid-state based lighting offers a number of advantages such as long life, high efficiency
and compactness compared to a conventional halogen tube based lighting.
Due to these advantages they are being increasingly used in a variety of lighting
applications including portable devices, home, and automotive lighting. Consequently,
there has been...
Successive approximation register analog-to-digital converters (SAR ADCs) have been widely used for medium-speed, medium-resolution applications due to their excellent power efficiency and digital compatibility. Recently, SAR ADCs are also penetrating into the applications which have been earlier dominated by delta-sigma ADCs and pipeline ADCs. However, the resolution of SAR ADCs...
The performance of the power take-off (PTO) system for a wave energy converter (WEC) depends largely on its control algorithm. This paper presents an adaptive damping control algorithm that improves power capture across a range of sea states. Validation for the numerical model was performed using data from two sources;...
Polymer electrolyte membrane (PEM) fuel cells are being studied for use as high efficiency power plants in alternative fuel vehicles. To maintain high efficiency the operating temperatures of the membranes in these fuel cells must be closely monitored and controlled. However, the environment inside of the fuel cell is not...
Dual referencing has been garnering a lot of attention in the power integrity community, specifically in the voltage mode driver application because it shows a lower overall power delivery noise (PDN) compared to other signal referencing types. Additionally, the increasing push to drive down package and board manufacturing costs is...
ZnO nanowires (NWs) are good candidates for chemical sensing because of their high surface-to-volume ratio. In this work, ZnO nanobridge sensors were fabricated utilizing a novel method which uses carbonized photoresist (C-PR) as a nucleation layer. The use of C-PR allows simultaneous growth and integration of NWs to lithographically-defined features....
Relay-assisted cooperative communications are promising solutions for error-performance improvement and cell coverage extension. In this thesis, we propose several efficient cooperative relay communication schemes. First, an efficient space-time coded cooperative relay communications scheme that employs linear precoding and transmission-pattern selection is proposed. This is built upon an existing block linear...
Short-range wireless communications continually attract interest from both industry and academia, and it is changing our life in every aspect in the last decade. The design of wireless transceivers is the bottleneck for variety applications, due to RF modeling inaccuracy, stringent FCC regulations over the transmitted power spectrum, interference, multi-path...
This thesis studies cooperative techniques that rely on femtocell user diversity to improve the downlink communication quality of macrocell users. We analytically analyze and evaluate the achievable performance of these techniques in the downlink of Rayleigh fading channels. We provide an approximation of both the bit-error rate (BER) and the...
Peer-to-Peer (P2P) based distributed storage systems have gain much popularity in recent years. These systems rely greatly on the data redundancy to be robust under network dynamics, i.e., the dynamics of peer entering and departing the network. Hence, it is important to implement mechanisms for maintaining a certain level of...
Low power, high speed serial transceivers are employed in a wide range of applications ranging from chip-to-chip, backplane, and optical interconnects. Apart
from being capable of handling a wide range of data rates, the transceivers should
have low power consumption (mW/Gbps) and be fully integrated. This work
discusses enabling techniques...
The decrease of switching times accompanied by the corresponding increase of
clock speeds and data rates, contributes to improve the overall system
computational performance. At the same time, they also affect wireless
communications due to an increment in the emissions of electromagnetic
radiation on the radio bands.
In this dissertation...
Resistive random access memory (RRAM) is a non-volatile memory technology based on resistive switching in a dielectric or semiconductor sandwiched between two different metals. Also known as memristors, these devices are potential candidates for a next-generation replacement for flash memory. In this thesis, bipolar resistive switching is reported for the...
Ocean wave energy has great potential to develop into a strong and reliable form of renewable energy. As the technology develops, more wave energy converters will be grid interconnected and the variable nature of the ocean will begin to influence the stability of the electrical grid system. There are many...
The fast growth of wind energy utilization has necessitated research into wind energy integration. Due to the variable nature of wind and the forecasting challenges, it is desirable to utilize wind energy alongside energy storage sources for reliable wind energy integration. This work details the design of a 25 kW...
As the semiconductor industry works to integrate increasingly more "non-CMOS" devices onto CMOS ICs, compact model development has become an important step in the circuit/system verification tool flow. This research focuses on the two- and three-dimensional modeling of the physical phenomena that occur in nanoscale magnetic devices. This includes the...
Renewable energy is a topic of significant interest and importance in the world today. Ocean wave energy, particularly in areas such as the Oregon Coast, has considerable potential as a renewable resource. However, to rightly evaluate the overall cost of energy for wave energy converters, survivability and maintenance issues must...
The world's demand for energy is an ongoing challenge, which has yet to be overcome.
The efforts to find clean energy alternatives to fossil fuels have been hampered by the
lack of investment in technology and research. Among these clean energy alternatives
are ocean waves and wind. Wind power is...
The imperfections of the propagation channel due to channel fading and the self-generated noise from the RF front-end of the receiver cause errors in the received signal in electronic communication systems. When network coding is applied, more errors occur because of error propagation due to the inexact decoding process. In...
Hand-held devices are among the most successful consumer electronics in modern society. Behind these successful devices, lies a key analog design technique that involves high-performance analog-to-digital conversion combined with very low power consumption. This dissertation presents two different approaches to achieving high power efficiency from a two-step pipelined architecture, which...
The future of mixed-signal, memory, and microprocessor technologies are dependent on ever increasing analog and digital integration, higher cell densities, and demand for more processing power. As a result MOSFET device dimensions continue to shrink to meet these demands. A side effect of device scaling is increased variability at each...
Given a video, we would like to recognize group activities, localize video parts where these activities occur, and detect actors involved in them. To this and, we propose a novel, mid-level feature, called control point, for representing group activities. The control points are aimed at summarizing visual cues, lifting from...
As CMOS processes size continues to shrink, a number of factors limit the ability of analog circuit performance to scale with the process. These issues include smaller transistor intrinsic gains and lower supply voltages. However, scaling continues to increase the speed and decrease the power of digital circuits. In this...
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...
In networked control systems (NCS) information or packets usually flow from a
sensor or a set of sensors to a remotely located controller. Then the controller
processes the received information and sends a series of control commands to the
actuators through a communication network which could be either wireless or...
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...
The number of wind turbines and wind farms in the Pacific Northwest has increased dramatically in the past six years, which represents a significant amount of electrical generation capacity connected to the public electric grid. However, the variable nature of wind sometimes introduces excessive power, or conversely shortages, in power...
The central focus of this thesis is the design, fabrication and characterization of amorphous oxide semiconductor (AOS) thin-film transistor (TFT) current mirrors. The thin-film deposition and circuit fabrication methods used to realize zinc tin oxide (ZTO) TFT
current mirrors are addressed in order to elucidate the processing challenges for this...