Advances in electronic systems have lead to the demand for high resolution, high bandwidth Analog-to-Digital Converters (ADCs). Oversampled ADCs are well- known for high accuracy applications since they benefit from noise shaping and they usually do not need highly accurate components. However, as a consequence of oversampling, they have limited...
Probabilistic models have been successfully applied for a wide variety of problems, such as but not limited to information retrieval, computer vision, bio-informatics and speech processing. Probabilistic models allow us to encode our assumptions about the data in an elegant fashion and enable us to perform machine learning tasks such...
The classical store-and-forward routing has and will continue to be the most important routing architecture in many modern packet-switched communication networks. In a packet-switched network, data is sent in the form of discrete packets that traverse hop-by-hop from a source to a destination. At each intermediate hop, the router stores...
As CMOS processes keep scaling down devices, the maximum operating frequencies of CMOS devices increase, and hence circuits can process very wide band signals. Moreover, the small physical dimensions of transistors allow the placing of many more blocks into a single chip, including highly accurate analog blocks and complicated digital...
Since free riders in P2P network reduce the system's performance, how to maintain and encourage the nodes' cooperation is an important aspect of P2P related research. In this thesis, a P2P system is modeled based on two games: stag hunt game and snowdrift game. To relate the model to the...
For building robust software applications, it is important for the software engineer to make efficient use of the available building blocks. Learning the basic language constructs is only the first step in this process. It is becoming increasingly important for software engineers, especially students, to get acquainted with the available...
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...
We present the evolution of a reasoning system for inferring dimension information in
spreadsheets. The three papers included in this thesis show how the initial system can be
used to check the consistency of spreadsheet formulas and thus is able to detect errors in
spreadsheets, and the evolution to a...
Dimensionality reduction (DR) is an efficient approach to reduce the size of
data by capturing the informative intrinsic features and discarding the noise. DR
methods can be grouped through a variety of categories, e.g. supervised/ unsupervised,
linear/non-linear or parametric/non-parametric. Objective function based
methods can be grouped into convex and non...
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...
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...
Parallel processors are classified into two classes: shared-memory multiprocessors and distributed- memory multiprocessors. In the shared-memory system, processors communicate through a common memory unit. However, in the distributed multiprocessor system, each processor has its own memory unit and the communications among the processors are performed through an interconnection network. Thus,...
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...
This dissertation addresses two fundamental problems in computer vision—namely,
multitarget tracking and event recognition in videos. These problems are challenging
because uncertainty may arise from a host of sources, including motion blur,
occlusions, and dynamic cluttered backgrounds. We show that these challenges can be
successfully addressed by using a multiscale,...
This dissertation addresses a number of inter-related and fundamental problems in computer vision. Specifically, we address object discovery, recognition, segmentation, and 3D pose estimation in images, as well as 3D scene reconstruction and scene interpretation. The key ideas behind our approaches include using shape as a basic object feature, and...
Visual programming languages (VPLs) have been widely used to support end-user programming. However, end users are still not able to reuse code as actively as professional programmers, even when given abundant resources such as a large VPL program repository. One reason may be that current VPL development environments lack features...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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....
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...
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...
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...
This work presents a residential load simulation framework that allows the user to test the effectiveness of peak reduction, peak shifting, and valley filling load management strategies on a representative residential load prior to physical smart sensor and load control deployment. The simulation methodology uses household occupancy, appliance time-of-use, and...
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...
Beaversource provides both code-hosting tools and social networking in one place. Students and faculty at Oregon State University have been using Beaversource to host their projects, both for classwork and research. Several usability problems were reported in a survey conducted on Beaversource last year. Some of these issues were severe...
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...
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...
Free/Open Source Software (FOSS) is a powerful development paradigm for
creating software. Increasingly more FOSS projects, like Firefox and Android, are
integrated into mainstream technology. It is important that FOSS projects serve its
diverse user base well. Several surveys have found that existing FOSS communities
are very homogenous populations and...
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...
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 Internet is growing rapidly in terms of websites, users and uses. People use the Internet for reference, shopping, social networking, communications, business and much more. Though the Internet is useful, there are many risks associated with its use, like malicious websites, identity theft, hateful content and fraudulent practices. Online...
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...
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...
A distributed system is a network of multiple autonomous computational nodes designed primarily for performance scalability and robustness. The performance of a distributed system depends critically on how tasks and resources are distributed among the nodes. Thus, a main thrust in distributed system research is to design schemes for distributing...
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...
Acting intelligently to efficiently solve sequential decision problems requires the ability to extract hierarchical structure from the underlying domain dynamics, exploit it for optimal or near-optimal decision-making, and transfer it to related problems instead of solving every problem in isolation. This dissertation makes three contributions toward this goal.
The first...
Within the past several years the technology of high-throughput sequencing has transformed the study of biology by offering unprecedented access to life's fundamental building block, DNA. With this transformation's potential a host of brand-new challenges have emerged, many of which lend themselves to being solved through computational methods. From de...
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...
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...
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...
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...