Index Catalog // ScholarsArchive@OSU

A comparative study between sinusoidal and squarewave clocking for alleviating the jitter limitation in multi-gigaHertz ADCs

Creator:: Kesharwani, Divya
Abstract:: Various applications like wireless UWB communication, fast data acquisition systems and digital storage oscilloscopes needs ADCs with instantaneous input signal bandwidth from 0.1-40 GigaHertz range with 6-10 bits of resolution -- a challenging task and an impressive goal to achieve. Flash ADCs have been conventionally employed to achieve these goals...
Resource Type:: Masters Thesis

Feedback in multiple antenna wireless communication systems

Creator:: Xu, Tao
Abstract:: Multiple-input multiple-output wireless systems promise significant capacity gain and/or diversity gain over single antenna systems. If channel state information (CSI) is available at both the transmitter and the receiver, the performance can be further improved. In this thesis, first, we study binary index feedback problem in beamforming systems when the...
Resource Type:: Dissertation

Understanding the ultra-wideband channel within a computer chassis

Creator:: Redfield, Stephen J.
Abstract:: Recent developments in computing technology have generated a demand for more streamlined and effective test systems. By replacing traditional in-chassis wired interconnects with a broadcast wireless system, fault detection and error susceptibility will drastically improve, input/output capabilities will expand, and routing complexity will decrease. Ultra-wideband impulse radio's (UWB-IR) characteristic multipath-immunity...
Resource Type:: Masters Thesis

Computationally efficient block diagonalization for downlink multiuser MIMO-OFDM systems

Creator:: El Amrani, Samia
Abstract:: One of the key challenges in downlink multiuser multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) systems is the mitigation of the multi-access interference when different users share the same subcarriers. In this work, the block diagonalization (BD) algorithm for inter-user interference pre-cancelation is extended to MIMO-OFDM systems. However, in...
Resource Type:: Masters Thesis

iMAC : improved medium access control for multi-channel multi-hop wireless networks

Creator:: Maiya, Megha
Abstract:: Trends in wireless networks are increasingly pointing towards a future with multi-hop networks deployed in multi-channel environments. In this thesis, we present the design for iMAC—a protocol targeted at medium access control in such environments. iMAC uses control packets on a common control channel to faciliate a three-way handshake between...
Resource Type:: Masters Thesis

Learning ranking functions for efficient search

Creator:: Xu, Yuehua
Abstract:: This dissertation explores algorithms for learning ranking functions to efficiently solve search problems, with application to automated planning. Specifically, we consider the frameworks of beam search, greedy search, and randomized search, which all aim to maintain tractability at the cost of not guaranteeing completeness nor optimality. Our learning objective for...
Resource Type:: Dissertation

From multitarget tracking to event recognition in videos

Creator:: Brendel, William
Abstract:: 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,...
Resource Type:: Dissertation

An adiabatic approach to analysis of time inhomogeneous Markov chains : a queueing policy application

Creator:: Zacharias, Leena
Abstract:: 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...
Resource Type:: Masters Thesis

Optimal load and resource balance in internet distributed systems

Creator:: Nishida, Hiroshi
Abstract:: 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...
Resource Type:: Dissertation

Algorithms for massive biological datasets

Creator:: Bryant, Douglas W. (Douglas Wesley)
Abstract:: 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...
Resource Type:: Dissertation

Optimal communications system design for array-based electric generation

Creator:: Orozco, Ricardo
Abstract:: 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...
Resource Type:: Masters Thesis

Simulator for optimizing performance and power of embedded multicore processors

Creator:: Goska, Benjamin J.
Abstract:: This work presents improvements to a multi-core performance/power simulator. The improvements which include updated power models, voltage scaling aware models, and an application specific benchmark, are done to increase the accuracy of power models under voltage and frequency scaling. Improvements to the simulator enable more accurate design space exploration for...
Resource Type:: Masters Thesis

High efficiency wideband low-power delta-sigma modulators

Creator:: Lee, Sang Hyeon
Abstract:: Delta-sigma analog-to-digital converters traditionally have been used for low speed, high resolution applications such as measurements, sensors, voice and audio systems. Through continued device scaling in CMOS technology and architectural and circuit level design innovations, they have even become popular for wideband, high dynamic range applications such as wired and...
Resource Type:: Dissertation

Detection and Segmentation of Bird Song in Noisy Environments

Creator:: Neal, Lawrence W.
Abstract:: Recent work in machine learning concerns the detection and identification of bird species from audio recordings of their vocalizations. Such analysis can yield valuable ecological information concerning the activity and distribution of species in the wild. Current species-identification methods require individual syllables of bird audio as input, but field-collected audio...
Resource Type:: Honors College Thesis

Ultra-wideband indoor localization systems

Creator:: Ye, Ruiqing
Abstract:: Indoor localization systems have a variety of applications such as tracking of assets, indoor robot navigation, and monitoring of people (e.g. patients) in hospitals or at home. Global positioning system (GPS) offers location accuracy of several meters and is mainly used for outdoor location-based applications as its accuracy degrades significantly...
Resource Type:: Dissertation

Efficient detection and scheduling for MIMO-OFDM systems

Creator:: Liu, Wei
Abstract:: Multiple-input multiple-output (MIMO) antennas can be exploited to provide high data rate using a limited bandwidth through multiplexing gain. MIMO combined with orthogonal frequency division multiplexing (OFDM) could potentially provide high data rate and high spectral efficiency in frequency-selective fading channels. MIMO-OFDM technology has been widely employed in modern communication...
Resource Type:: Dissertation

Learning approaches for the early detection of kickback in chainsaws

Creator:: Arnold, Drew D.
Abstract:: Among the many safety hazards facing chainsaw operators, the phenomenon known as kickback is the most dangerous. Kickback occurs when the chain at the tip of the chainsaw is caused to stop abruptly, and transfers the energy of the cutting chain to motion of the saw. The saw will rotate...
Resource Type:: Masters Thesis

Linearizing techniques for voltage controlled oscillator based analog to digital converters

Creator:: Rao, Sachin B.
Abstract:: Voltage controlled oscillator (VCO) based ADC is an important class of time-domain ADC that has gained widespread acceptance due to their several desirable properties. VCO-based ADCs behave like an open-loop continuous time ΔΣ modulator and achieve excellent resolution by first order noise shaping the quantization error. However, the SNDR of...
Resource Type:: Dissertation

Fast queuing policies via convex relaxation

Creator:: Nguyen-Huu, Duong
Abstract:: Traditionally, networking protocol designs have placed much emphasis on point-to-point reliability and efficiency. With the recent rise of mobile and multimedia applications, other considerations such as power consumption and/or Quality of Service (QoS) are becoming increasingly important factors in designing network protocols. As such, we present a new flexible framework...
Resource Type:: Masters Thesis

Modeling and analysis of spur structure of digital-to-time conversion based frequency synthesizers

Creator:: Talwalkar, Sumit A.
Abstract:: Frequency synthesizers are critical components of all communication systems. This thesis considers the issue of undesirable frequency spurs of a relatively recent type of frequency synthesis architecture called digital-to-time conversion (DTC). The DTC-based frequency synthesis architecture has important performance benefits over older frequency synthesizers, such as fast frequency switching, large...
Resource Type:: Dissertation

Testing of wave energy converters using the Ocean Sentinel Instrumentation Buoy

Creator:: Lettenmaier, Terrance
Abstract:: Ocean testing of Wave Energy Converter (WEC) prototypes is necessary to facilitate commercial WEC development. The Ocean Sentinel Instrumentation Buoy, completed in August 2012, provides a stand-alone load for WEC prototypes during ocean testing. The first part of this work was to develop the power conversion and data acquisition equipment...
Resource Type:: Dissertation

Development of a grid-scale energy storage solution via demand response using model predictive control of multiple residential water heaters

Creator:: Halamay, Douglas A.
Abstract:: As the growth of renewable energy sources, such as wind, solar, and ocean wave, increases, their impact on the electrical grid has been rapidly escalating. Although renewable resources have been able to offset some traditional generation, they have also brought a need for increasing reserve capacity due to their non-dispatchable,...
Resource Type:: Dissertation

Adiabatic Markov Decision Process : convergence of value iteration algorithm

Creator:: Duong, Thai
Abstract:: Markov Decision Process (MDP) is a well-known framework for devising the optimal decision making strategies under uncertainty. Typically, the decision maker assumes a stationary environment which is characterized by a time-invariant transition probability matrix. However, in many real-world scenarios, this assumption is not justified, thus the optimal strategy might not...
Resource Type:: Masters Thesis

Design techniques for low power high speed successive approximation analog-to-digital converters

Creator:: Lin, Jiaming
Abstract:: This dissertation presents two high-speed pipeline successive approximation analog-to-digital converters (SAR ADCs). Capacitive DACs and resistive DACs are utilized in these two pipeline SAR ADCs, respectively. The pipeline SAR ADC with capacitive DACs can save 50% switching power compared with other time-interleaved SAR ADCs since the total capacitance of the...
Resource Type:: Dissertation

The MiniSpec : a low-cost, compact, FPGA-based gamma spectrometer for mobile applications

Creator:: Becker, Eric M.
Abstract:: There is a significant role in emergency response and personal radiation safety that can be played by a compact radiation detector that is capable of identifying radionuclides. Herein is described the design, construction, and characterization of a small, low-cost, low-power gamma ray spectrometer prototype intended to fill this role, conducted...
Resource Type:: Masters Thesis

Energy and area efficient techniques for data converters

Creator:: Venkatram, Hariprasath
Abstract:: Data converters are ubiquitous building blocks of a signal chain. The rapid increase in communication and connectivity devices presents new avenues for pushing the state of the art analog to digital converters. Techniques for improving resolution, bandwidth, linearity and bit-error rate, while reducing the power, energy and area is the...
Resource Type:: Dissertation

Reinforcement learning-based off-equilibrium incentives to approximate the VCG mechanism

Creator:: Moissinac, Béatrice
Abstract:: Auctions are used to solve resource allocation problem between many agents and many items in real-world settings. Unfortunately, in most cases, it is possible for selfish agents to manipulate the system for their own interest at the expense of the social welfare. Such manipulation can be prevented using the Vickrey-Clarke-Groves...
Resource Type:: Masters Thesis

Multi-instance multi-label learning : algorithms and applications to bird bioacoustics

Creator:: Briggs, Forrest
Abstract:: We consider the problem of supervised classification of bird species from audio recordings in a real-world acoustic monitoring scenario (i.e. audio data is collected in the field with an omnidirectional microphone, without human supervision). Obtaining better data about bird activity can assist conservation efforts, and improve our understanding of their...
Resource Type:: Dissertation

Micropower incremental analog-to-digital converters

Creator:: Chen, Chia-Hung
Abstract:: Incremental ADCs (IADCs) have many advantages for low-frequency high-accuracy data conversion—they are easy to multiplex between channels, need simpler digital decimation filter, and allow extended counting with a Nyquist-rate ADC. A single-loop incremental ADC was designed and fabricated in 90 nm for a biosensor interface circuit. It incorporates one integrator,...
Resource Type:: Dissertation

Compensation method of the excess loop delay in continuous-time delta-sigma ADCs based on model matching approach

Creator:: Guo, Jia
Abstract:: Continues-Time (CT) Delta-Sigma (ΔΣ) Analog-to-Digital Converters (ADCs) have one important constrain, namely the excess loop delay. Most previous excess lop delay compensation methods need to know the exact value of the excess loop delay in advance. However, the value of the excess loop delay is a uniformly distribution random variable....
Resource Type:: Masters Thesis

An ensemble method for macrosoma prediction

Creator:: Qin, Lu
Abstract:: Macrosomia is a medical term describing a new baby born with an excessive birth weight (greater than 4000g). Fetal macrosomia may lead to both pregnancy complications, and increased risk of mother's and baby's health problems after birth. But the potential complications may be mitigated by a cesarean delivery. As such,...
Resource Type:: Masters Thesis

A remotely operated, autonomous wave energy converter system

Creator:: Lewis, Timothy M.
Abstract:: The potential for electric energy generation from ocean waves is substantial and much research is being conducted on the conversion process as a renewable, grid-connected, power source. Some of the same attributes that make wave energy harvesting attractive as a grid-connected source also make it attractive as a remote, or...
Resource Type:: Dissertation

Parameter estimation of Gaussian hierarchical model using Gibbs sampling

Creator:: Mbuthia, Juliana
Abstract:: Gibbs sampling method is an important tool used in parameter estimation for many probabilistic models. Specifically, for many scenarios, it is difficult to generate high-dimensional data samples from its joint distribution. The Gibbs sampling provides a way to draw high-dimensional data via the conditional distributions which are typically easier to...
Resource Type:: Masters Thesis

Wideband and high accuracy delta sigma modulation data converter

Creator:: Jung, Youngho
Abstract:: Nowadays, needs for wideband and high accuracy analog-to-digital converter are increasing rapidly in manifold applications such as wireless communication, digital video and other consumer electronics. Besides, low power consumption is required to have longer battery life in portable systems. CMOS technology scaling and innovative modulator topology make the implementation much...
Resource Type:: Dissertation

Position estimation in indoor localization system

Creator:: Qiao, Tianzhu
Abstract:: Indoor positioning systems can be used for many applications such as indoor navigation,emergence response, asset monitoring, and shopper assistance. Due to the weak received signal and multipath reflection, the global positioning system (GPS) generally does not work in indoor environments. There are a variety of radio frequency (RF) signals and...
Resource Type:: Dissertation

Linearity enhancement techniques for data converters

Creator:: Cao, Jinzhou
Abstract:: Data converters are essential interface circuits between the analog world that people live in and the digital processors that people live with. Linearity, which often is a tradeoff against other performance criteria, is one of the major performance demands from applications for both analog-to-digital converts (ADC) and digital-to-analog converters (DAC)....
Resource Type:: Dissertation

Data Collection in Sensor Networks via the Novel Fast Markov Decision Process Framework

Creator:: Duong, Thai
Abstract:: We investigate the data collection problem in sensor networks. The network consists of a number of stationary sensors deployed at different sites for sensing and storing data locally. A mobile element moves from sites to sites to collect data from the sensors periodically. There are different costs associated with the...
Resource Type:: Masters Thesis

Supervised Hierarchical Segmentation for Bird Bioacoustics

Creator:: Tjahja, Teresa V.
Abstract:: Bioacoustics analysis can be used to conduct environmental monitoring by detecting the presence of birds species. This analysis usually involves identifying the species from their calls. In most frameworks, bird song syllables are extracted from audio recordings and individual syllables are input to a classifier to identify the species. Extraction...
Resource Type:: Masters Thesis

Ultra-Wideband Relay Communication Systems

Creator:: Abbasi, Arash
Abstract:: Impulse-radio ultra-wide-band (IR-UWB) signaling is a promising technique for high-speed, short-range relay communications networks. Depending on how the relay node retransmits the signal, there are two main relay schemes: conventional one-directional (one-way) relay model, and bi-directional (two-way) relay model. In bi-directional relay communications, wireless network coding (WNC), also called physical-layer...
Resource Type:: Dissertation

A Direction-Sensitive Radiation Detector for Low-Altitude, UAV-based Radiological Source Search

Creator:: Becker, Eric M. (Eric Matthew)
Abstract:: Many devices and methods for radiological searches are currently being developed, including scanning using simple detectors, mapping using large-volume detectors, and Compton imaging using 3-D position sensitive detectors. However, these devices are typically expensive and the methods used require long periods of time to generate a direction or location. The...
Resource Type:: Dissertation

Network Coding, Random Matrices, and Their Applications to Communication Systems

Creator:: Nguyen-Huu, Duong
Abstract:: In this work, we study network coding technique, its relation to random matrices, and their applications to communication systems. The dissertation consists of three main contributions. First, we propose efficient algorithms for data synchronization via a broadcast channel using random network coding. Second, we study the resiliency of network coding...
Resource Type:: Dissertation

Machine Learning Methods for Computational Sustainability

Creator:: Liu, Liping
Abstract:: Maintaining the sustainability of the earth’s ecosystems has attracted much attention as these ecosystems are facing more and more pressure from human activities. Machine learning can play an important role in promoting sustainability as a large amount of data is being collected from ecosystems. There are at least three important...
Resource Type:: Dissertation

Modeling, Fabrication, and Characterization of Magnetic Thin Films for Integrated Inductor and MRAM Applications

Creator:: Buford, Benjamin
Abstract:: Magnetic thin films have potential to improve devices such as on-chip inductors, and enable new technologies such as magnetic random access memory (MRAM). The use of magnetic cores in on-chip inductors is typically limited to applications well under 1 GHz. At higher frequencies, the performance of the magnetic core is...
Resource Type:: Dissertation

Power Efficient Architectures for High Accuracy Analog-to-Digital Converters

Creator:: Zhang, Yi
Abstract:: Incremental ADCs (IADCs) have found wide applications in sensor interface circuitry since, compared to ∆Σ ADCs, they provide low-latency high-accuracy conversion and easy multiplexing among multiple channels. On the other hand, continuous-time ∆Σ ADCs (CTDSM) have been receiving more and more attention as a power-efficient solution in targeting medium to...
Resource Type:: Dissertation

Simultaneous segmentation and classification of bird song using CNN

Creator:: Narasimhan, Revathy
Abstract:: In bioacoustics, automatic animal voice detection and recognition from audio recordings is an emerging topic for animal preservation. Our research focuses on bird bioacoustics, where the goal is to segment bird syllables from the recording and predict the bird species for the syllables. Traditional methods for this task addresses the...
Resource Type:: Masters Thesis

Position estimation in indoor localization with trilateration

Creator:: Su, Zhenqiang
Abstract:: Triangulateration uses geometric distance to estimate the location of user by employing techniques like received signal strength (RSS), time-of-arrival (TOA), time-difference-of-arrival (TDOA) and image processing. Radio frequency (RF) signal positioning using TOA or TDOA techniques generally requires timing synchronization of the anchors and/or the anchors and targets. If the desired...
Resource Type:: Dissertation

Learning with Partial Supervision for Clustering and Classification

Creator:: Pei, Yuanli
Abstract:: In the field of machine learning, clustering and classification are two fundamental tasks. Traditionally, clustering is an unsupervised method, where no supervision about the data is available for learning; classification is a supervised task, where fully-labeled data are collected for training a classifier. In some scenarios, however, we may not...
Resource Type:: Dissertation

Visualization and analysis of sensor data for detecting microclimate cold air pools

Creator:: Singh, Satpreet Harcharan
Abstract:: Cold air pools are spatiotemporal phenomena that occur when cold air from higher elevations roll down the slope to accumulate in lower elevations. Behaviors like this lead to microclimate anomalies such as the city of Corvallis (Oregon) experiencing persistent cold weather even on a sunny day. We analyze multivariate temperature...
Resource Type:: Masters Thesis

A Micro Scale Magnetic Particle Imaging System

Creator:: Lenox, Philip A.
Abstract:: Magnetic particle imaging (MPI) is a biomedical imaging technique which detects the presence of magnetic nanoparticles which have been introduced into the specimen prior to imaging. MPI has shown promise for real-time imaging with spatial resolution comparable to magnetic resonance imaging (MRI). MPI research has focused predominantly on the development...
Resource Type:: Masters Thesis

Sliding Mode Control of Oscillating Water Column Wave Energy Converters

Creator:: Brown, Danielle R.
Abstract:: This thesis concerns the development of a direct torque control strategy using a sliding mode control approach to optimize the power output of an oscillating water column (OWC) wave energy converter (WEC). The OWC WEC is a device that has a submerged vertical tail tube open at both ends, which...
Resource Type:: Masters Thesis

Coupled Compressive Sensing : Sequential Reinforcement Approach

Creator:: De Silva, Shashini A.
Abstract:: We consider multiple Compressive Sensing (CS) problems wherein the supports of signal vectors of CS problems are restricted to satisfy a collection of joint logical constraints, which we refer to as coupling constraints. We consider a case where the coupling constraints are encoded in a graph and present a sequential...
Resource Type:: Masters Thesis

Pixel- and Frame-level Video Labeling using Spatial and Temporal Convolutional Networks

Creator:: Lei, Peng
Abstract:: This dissertation addresses the problem of video labeling at both the frame and pixel levels using deep learning. For pixel-level video labeling, we have studied two problems: i) Spatiotemporal video segmentation and ii) Boundary detection and boundary flow estimation. For the problem of spatiotemporal video segmentation, we have developed recurrent...
Resource Type:: Dissertation

Design Considerations and Circuit Techniques for Robust Ring-Amplifiers

Creator:: Venkatachala, Praveen Kumar
Abstract:: Ring amplifiers (ringamps) have shown excellent power efficiency in the latest state-of-the-art analog to digital converters (ADCs). This thesis describes circuit techniques to ensure robust operation of ringamps using standard analog techniques and proportional-integral-derivative(PID) controller analogy. Large-signal and small-signal analysis of a ringamp are performed using simple RC settling and...
Resource Type:: Dissertation

Lamb Wave Mode Decomposition and Its Applications in Structural Health Monitoring

Creator:: Zoubi, Ahmad Bassil
Abstract:: Structural health monitoring (SHM) systems perform automated non-destructive damage detection and characterization for a variety of large structures including civil structures such as bridges and aerospace structures such as aircrafts and space vehicles. The goals of SHM include preventing catastrophic structural failures, increasing reliability, reducing maintenance costs, and increasing the...
Resource Type:: Dissertation

Anomaly Detection: Theory, Explanation and User Feedback

Creator:: Siddiqui, Md Amran
Abstract:: Anomaly detection has been used in variety of applications in practice, including cyber-security, fraud detection and detecting faults in safety critical systems, etc. Anomaly detectors produce a ranked list of statistical anomalies, which are typically examined by human analysts in order to extract the actual anomalies of interest. Unfortunately, most...
Resource Type:: Dissertation

Crowdsourcing via Pairwise Co-occurrences: Identifiability and Algorithms

Creator:: Ibrahim, Shahana
Abstract:: Crowdsourcing is a popular paradigm to address the high demands for labeled data in big data deluge. It aims to produce accurate labels by eﬀectively integrating noisy, non-expert labeling from crowdsourced workers (annotators). The machine learning community has been studying eﬀective crowdsourcing methods for many years, and many models and...
Resource Type:: Masters Thesis

Power Network Parameter Correction via Sparse Unsupervised Regression

Creator:: Senaratne, Galpottage Dilan S.
Abstract:: Accurate information of power network parameters is essential for performing various power system monitoring and control tasks including state estimation, economic dispatch, and contingency analysis. In this paper, we present a novel approach of power network parameter correction wherein we exploit the sparse nature of parameter errors. Parameter error correction...
Resource Type:: Masters Thesis

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