Digital Commons Network^™

Using Analytic Techniques To Resolve Numerical Issues In A Pseudo Spectral Solver For A Black Hole Scalar Field, Eugene Munro

Theses

In this paper, we will solve the Hamiltonian constraint describing a curved general relativistic spacetime to find initial data describing how a black hole exists in vacuum. This has been done before by other researchers [Ansorg, 2004], and we will be adapting our own methods to an existing pseudo spectral Poisson solver [Gourgoulhon, 2001]. The need for this adaptation arises from improper numerical handling, done by pseudo spectral-methods, of a large part the Hamiltonian constraint equation due to the presence of the black hole singularity. To resolve a portion of this issue up to a given order, we will determine …

Regularization Of Dynamic Time Warping Barycenter Averaging, With Applications In Sign Classification, John A.W.B. Costanzo

Theses

Sign language synthesis is a useful tool in addressing many of the issues faced by deaf communities. Sign languages are as different from spoken languages as spoken languages are from each other, and hence deaf persons raised learning sign language are not automatically proficient in communicating in written language. Existing methods of generating signing avatars are clunky and often unintuitive; hence the ability to classify gestures common to sign language using only data recorded by video would simplify the process dramatically.

Methods of gesture classification require a way to compare time series, and often (in particular, for k-means clustering) require …

A Dynamic Magnetic Resonance Imaging (Mri) Phantom Based On Electric Field Induced Residual Dipolar Couplings, Yujie Qiu

Theses

Multi-center functional MRI (fMRI) research studies are advantageous but unavoidably introduce variations in the results due to differences in imager vendor, magnetic field strength, imaging pulse sequences, and many other aspects. These variations make combining data from different MRI centers risky. Even for a single MRI center, temporal variations over the course of a study can make combining data problematic. Therefore, it is necessary in both situations to perform quality assurance (QA) measurements on a regular basis. Unfortunately, there are no dynamic standards or phantoms as they are called in the MRI community, which can mimic the small, rapidly changing …

Construction Of Multi-Mode Fiber Modes Using Phase Masks, Alexandre Tulikumwenayo

Theses

Transverse fiber modes are the distribution of electromagnetic fields in the cross-section of an optical fiber through which light propagates in the fiber. Research is being conducted to explore the usage of fiber modes with the purpose of increasing the capacity and reach of optical fibers. Mode Division Multiplexing, an area in which reseach is being conducted with the same purpose, is a multiplexing scheme used in optical networks that maps data channels onto different modes, and multiplexes these modes into one fiber for transmission. This thesis focuses on the study of modes in multi-mode fibers, and the simulation of …

Analysis Of Connecting Rod Bearing Design Trends Using A Mode-Based Elastohydrodynamic Lubrication Model, Travis M. Blais

Theses

Available design trends for big end connecting rod bearings utilize widely adopted rapid methods for prediction of minimum film thickness due to their superior speed and ease of use. However, they impose unrealistic assumptions such as surface rigidity, which could compromise the accuracy of results. The significance of structural elasticity and updated models was investigated using a mode based elastohydrodynamic lubrication model which includes body forces, mass conserving cavitation, and surface roughness. Eight physical connecting rods were modeled using finite element methods and simulated over a variety of conditions, varying engine speed, bearing clearance, and oil viscosity. The results show …

Effects Of Reputation And Aesthetics On The Credibility Of Search Engine Results, Bryan Christiansen

Theses

Search engines are the primary gatekeepers of online information, but are judged differently than traditional gatekeepers due to the interactive and impersonal nature of the online search process. The researcher distributed an online survey with 141 respondents and conducted 22 observational interviews. Information credibility was tested through measures of expertise, goodwill, and trustworthiness, which were each correlated with perceived reputation and perceived aesthetics. Search engine reputation was found to have moderate correlations with expertise and trustworthiness, and a lesser, but still moderate correlation with goodwill. Aesthetics was related to the credibility measures in similar but lesser proportions. Interviews indicated search …

Epistemic Uniqueness, Permissiveness, And Peer Disagreement, Tung-Ying Wu

Theses

Disagreement is very common in controversial areas such as politics, law, religion, and philosophy, but it is also very common in daily interactions. Clearly, in every disagreement it is neither the case that one should always defer to others, nor that one should always insist she is right. Instead, one should first evaluate the credence of the dissenter’ testimony. Suppose she recognizes the dissenter is her epistemic peer. In the current debate of the epistemology of peer disagreement, it is controversial whether one is rationally required to suspend one’s judgment when disputing with peers. Three different views have been proposed: …

An Sir Approach To Modeling Business Interactions In A Marketplace, Jessica R. Beiter

Theses

As interest in online coupons from distributors like Groupon and Living Social have grown, eBay has proposed and built a marketplace. This marketplace is called eBay Local. It is a place where local merchants can post coupons that distributors can bid on the right to publish. Based on some initial data, we have built a model to t and predict the growth of this marketplace. The influence of salesmen and organic growth convert potential merchants into active members of the marketplace posting their goods and services. We have modeled the recruitment and retention of businesses within the marketplace, based on …

Power Profile Obfuscation Using Rrams To Counter Dpa Attacks, Ganesh Chandrakantrao Khedkar

Theses

Side channel attacks, such as Differential Power Analysis (DPA), denote a special class of attacks in which sensitive key information is unveiled through information extracted from the physical device executing a cryptographic algorithm. This information leakage, known as side channel information, occurs from computations in a non-ideal system composed of electronic devices such as transistors. Power dissipation is one classic side channel source, which relays information of the data being processed. DPA uses statistical analysis to identify data-dependent correlations in sets of power measurements.

Countermeasures against DPA focus on hiding or masking techniques at different levels of design abstraction and …

Stability Analysis Of Switched Dc-Dc Boost Converters For Integrated Circuits, Kevin Fronczak

Theses

Boost converters are very important circuits for modern devices, especially battery- operated integrated circuits. This type of converter allows for small voltages, such as those provided by a battery, to be converted into larger voltage more suitable for driving integrated circuits. Two regions of operation are explored known as Continuous Conduction Mode and Discontinuous Conduction Mode. Each region is analyzed in terms of DC and small-signal performance. Control issues with each are compared and various error amplifier architectures explored. A method to optimize these amplifier architectures is also explored by means of Genetic Algorithms and Particle Swarm Optimization. Finally, stability …

Math Expression Retrieval Using Symbol Pairs In Layout Trees, David Stalnaker

Theses

We have developed a layout-based math retrieval system by indexing on pairs of symbols in mathematical expressions. Existing approaches to layout-based retrieval include tree edit distance-based matching on MathML trees (Kamali and Tompa, 2013) and longest common subsequence matching in LATEX strings (Kumar et al., 2012). In our work, we compare our new layout-based retrieval method with a math retrieval system built using the conventional text-based retrieval system Lucene (Zanibbi and Yuan, 2011), as such systems are commonly used for math search. We show that the search results returned by our system are scored by participants in a study as …

Workforce Planning And Facility Utilization Using A Two-Stage Stochastic Recourse Approach, Anirudha Kulkarni

Theses

Hi-tech manufacturing uses sophisticated and capital intensive processes that require a highly skilled workforce. Fluctuating demand leads to either a shortage of skilled workers that causes unmet demand or an excess of skilled labor that causes worker idleness. This mismatch in the available and required skillsets is a source of potential loss for the organization. This thesis formulates an industry-motivated workforce planning and facility utilization problem as a two-stage stochastic recourse program that considers fluctuating demand over a long planning horizon and includes business and labor rules, e.g., hiring, firing, overtime, cross-training, and shift swapping, that govern the structure of …

Large Substitution Boxes With Efficient Combinational Implementations, Christopher A. Wood

Theses

At a fundamental level, the security of symmetric key cryptosystems ties back to Claude Shannon's properties of confusion and diffusion. Confusion can be defined as the complexity of the relationship between the secret key and ciphertext, and diffusion can be defined as the degree to which the influence of a single input plaintext bit is spread throughout the resulting ciphertext. In constructions of symmetric key cryptographic primitives, confusion and diffusion are commonly realized with the application of nonlinear and linear operations, respectively. The Substitution-Permutation Network design is one such popular construction adopted by the Advanced Encryption Standard, among other block …

Dynamics And Control Of A Single-Line Maneuverable Kite, Christopher Donnelly

Theses

Through simulation, an automated control system for a single-line maneuverable kite is developed for application in kite wind energy production. The kite used in this study is a small, tension-controlled, single-line kite, commonly known as a fighter kite. These kites have a simple design, but flying them requires complex control of line tension and visual input. At low tether tension, the kite is unstable; spinning about the tether. Increasing tension in the tether causes the kite to deform and fly in the direction it was facing. Experienced fliers can produce intricate maneuvers and often participate in competitions with other fliers. …

Segmentation And Model Generation For Large-Scale Cyber Attacks, Steven E. Strapp

Theses

Raw Cyber attack traffic can present more questions than answers to security analysts. Especially with large-scale observables it is difficult to identify which packets are relevant and what attack behaviors are present. Many existing works in Host or Flow Clustering attempt to group similar behaviors to expedite analysis; these works often phrase the problem directly as offline unsupervised machine learning. This work proposes online processing to simultaneously model coordinating actors and segment traffic that is relevant to a target of interest, all while it is being received. The goal is not just to aggregate similar attack behaviors, but to provide …

Topographic Position And Land Cover Effects On Soil Organic Carbon Distribution Of Loess-Veneered Hillslopes In The Central United States, Thomas Rhanor

Theses

Soil organic carbon (SOC) is important both for its influence on agricultural productivity and for its role in the carbon cycle. The distribution of SOC is highly variable at the field scale both horizontally and vertically; a portion of SOC's variability can be attributed to differences in vegetative cover and to slope position. This study characterized and compared SOC concentration to a depth of 2 meters across 6 loess-veneered watersheds in the central United States. Data were collected as part of the Shawnee Hills Loess Catenas project, a collaboration between the U.S. Department of Agriculture (USDA) Natural Resources Conservation Service, …

An Examination Of Equilibria In The Multi-Site Iterated Prisoner's Dilemma, George A. Mcclain

Theses

Iterated Prisoner's Dilemma is a simple model for the interaction between two self-interested agents who can choose whether or not to cooperate with one another. Many real-world problems can be characterized in terms of the Iterated Prisoner's Dilemma, from the militarization of rival nations to the tradeoff between gas mileage and safety when purchasing a vehicle. The game theoretic properties of Iterated Prisoner's Dilemma are well understood, and previous research by Robert Axelrod into the performance of various strategies in a Darwinian environment is extensive. In this paper we extend Axelrod's work by investigating the dynamics of the Iterated Prisoner's …

Spatial Heterodyne Spectroscopy: Modeling And Interferogram Processing, Cara Perkins

Theses

This work presents a radiometric model of a spatial heterodyne spectrometer (SHS) and a corresponding interferogram-processing algorithm for the calculation of calibrated spectral radiance measurements. The SHS relies on Fourier Transform Spectroscopy (FTS) principles, and shares design similarities with the Michelson Interferometer. The advantages of the SHS design, including the lack of moving parts, high throughput, and instantaneous spectral measurements, make it suitable as a field-deployable instrument. Operating in the long-wave infrared (LWIR), the imaging SHS design example included provides the capability of performing chemical detection based on reflectance and emissivity properties of surfaces of organic compounds. This LWIR SHS …

Quantity And Composition Of Stream Dissolved Organic Matter In The Watershed Of Conesus Lake, New York, Morgan R. Bida

Theses

The watershed of Conesus Lake, New York is drained by more than 18 unique streams and several smaller tributaries and has multiple land uses, varying from highly agricultural to primarily wooded, making the lake an ideal study site for analysis of the effects of land use on various water quality parameters. Previous water quality and watershed-health studies at Conesus Lake have focused on the delivery of inorganic nutrients to the lake. We know much less, however, about the effects of watershed land use on the quantity and composition of dissolved organic matter (DOM) exported to the lake. We sought to …

Analysis Of Compressive Sensing For Hyperspectral Remote Sensing Applications, Maria Busuioceanu

Theses

Compressive Sensing (CS) systems capture data with fewer measurements than traditional sensors assuming that imagery is redundant and compressible in the spectral and spatial dimensions. This thesis utilizes a model of the Coded Aperture Snapshot Spectral Imager-Dual Disperser (CASSI-DD) to simulate CS measurements from traditionally sensed HyMap images. A novel reconstruction algorithm that combines spectral smoothing and spatial total variation (TV) is used to create high resolution hyperspectral imagery from the simulated CS measurements. This research examines the effect of the number of measurements, which corresponds to the percentage of physical data sampled, on the quality of simulated CS data …

Floristics And Above-Ground Biomass (Agb) In Peatlands In Peruvian Lowland Amazonia, Loreto – Peru, Elvis Valderrama

Theses

Amazonian forests comprise almost 10% of stored carbon (C) in the world’s land ecosystems. This C is held both in above-ground biomass (AGB) and in the soil. AGB in an individual plant depends on plant size, often measured in trees as height (H) and diameter (D), and the density of plant tissues, often approximated in trees by wood density (WD). Soil C storage depends on the balance between inputs from AGB due to mortality and senescence and outputs due to decay and erosion. Peatlands, wetlands recently described in northern Peruvian Amazonia, show unusually high rates of soil C accumulation. For …

Population Modeling With Delay Differential Equations, Shawna Nelson

Theses

We investigate a delay differential equation system version of a model designed to describe finite time population collapse.

The most commonly utilized population models are presented, including their strengths, weaknesses and limitations.

We introduce the Basener-Ross model, and implement the Hopf bifurcation test to identify whether there is a Hopf bifurcation in this system.

We attempt to improve upon the Basener-Ross model (which uses ordinary differential equations) by introducing delay differential equations to account for the gestational period of humans.

We utilize the singularity-removing transformation of the original Basener-Ross system for the delay differential equation system as well. The new …

Understanding And Modeling The Synchronization Cost In The Gpu Architecture, James Letendre

Theses

Graphic Processing Units (GPUs) have been growing more and more popu- lar being used for general purpose computations. GPUs are massively paral- lel processors which make them a much more ideal fit for many algorithms than the CPU is. The drawback to using a GPU to do a computation is that they are much less efficient at running algorithms with more complex con- trol flow. This has led to them being used as part of a heterogeneous system, usually consisting of a CPU and a GPU although other types of processors could be added. Models of GPUs are important in …

Usefulness Of Teaching Security Awareness For Middle School Students, Hani Alhejaili

Theses

Technology and the Internet bring many benefits to students. Studies show that technology and the available online resources encourage inquiry and support student success in schools. However, there are many threats to middle school students as a result of the misuse of technology. I believe that teaching security awareness for middle school students through an online interactive program is essential for reducing the risks that could affect them. The online interactive program should be multilingual, completely visual, continually updating, and suitable for both students and their families. Since many efforts have been made to minimize the risks, it has become …

Current Sensing Feedback For Humanoid Stability, Matthew Decapua

Theses

For humanoid robots to function in changing environments, they must be able to maintain balance similar to human beings. At present, humanoids recover from pushes by the use of either the ankles or hips and a rigid body. This method has been proven to work, but causes excessive strain on the joints of the robot and does not maximize on the capabilities of a humanlike body. The focus of this paper is to enable advanced dynamic balancing through torque classification and balance improving positional changes. For the robot to be able to balance dynamically, external torques must be determined accurately. …

Representing And Inferring Visual Perceptual Skills In Dermatological Image Understanding, Rui Li

Theses

Experts have a remarkable capability of locating, perceptually organizing, identifying, and categorizing objects in images specific to their domains of expertise. Eliciting and representing their visual strategies and some aspects of domain knowledge will benefit a wide range of studies and applications. For example, image understanding may be improved through active learning frameworks by transferring human domain knowledge into image-based computational procedures, intelligent user interfaces enhanced by inferring dynamic informational needs in real time, and cognitive processing analyzed via unveiling the engaged underlying cognitive processes.

An eye tracking experiment was conducted to collect both eye movement and verbal narrative data …

Phase Retrieval Using Power Measurements, Jamal Arif

Theses

Optical signals have two basic components that are power and phase, which can be demonstrated in both time and frequency domains. The common diagnostics which are available in the market only measure power component in time or frequency domain. However in certain areas phase measurements are also required. The phase retrieval techniques are used to calculate phase measurements from different methods. There are a number of applications where phase measurements are required like astronomy, wavefront sensing technique (James Webb space telescope), x-ray crystallography, fiber optic telecommunications etc. Various phase retrieval algorithms have been used in retrieving phase measurements in temporal …

Evaluation And Improvement Of The Workflow Of Digital Imaging Of Fine Art Reproduction In Museums, Jun Jiang

Theses

Fine arts refer to a broad spectrum of art formats, ie~painting, calligraphy, photography, architecture, and so forth. Fine art reproductions are to create surrogates of the original artwork that are able to faithfully deliver the aesthetics and feelings of the original. Traditionally, reproductions of fine art are made in the form of catalogs, postcards or books by museums, libraries, archives, and so on (hereafter called museums for simplicity). With the widespread adoption of digital archiving in museums, more and more artwork is reproduced to be viewed on a display. For example, artwork collections are made available through museum websites and …

Numerical Identification Of A Variable Parameter In 2d Elliptic Boundary Value Problem By Extragradient Methods, Selin Sariaydin

Theses

This work focuses on the inverse problem of identifying a variable parameter in a 2-D scalar elliptic boundary value problem. It is well-known that this inverse problem is highly ill-posed and regularization is necessary for its stable solution. The inverse problem is studied in an optimization framework, which is the most suitable framework for incorporating regularization. This optimization problem is a constrained optimization problem where the constraint set is a closed and convex set of the admissible coefficients. As an objective functional, we use both the output least squares and modified output least squares functionals. It is known that the …

A Graph Theoretic Approach To Quantifying Grey Matter Volume In Neuroimaging, Ashley Zanca

Theses

Brain atrophy occurs as a symptom of many diseases. The software package, Statistical Parametric Mapping (SPM) is one of the most respected and commonly used tools in the neuroimaging community for quantifying the amount of grey matter (GM) in the brain based on magnetic resonance (MR) images. One aspect of quantifying GM volume is to identify, or segment, regions of the brain image corresponding to grey matter. A recent trend in the field of image segmentation is to model an image as a graph composed of vertices and edges, and then to "cut" the graph into subgraphs corresponding to different …