Physical Sciences and Mathematics Commons^™

Information Overload In Structured Data, Pinar Yanardag Delul

Open Access Dissertations

Information overload refers to the difficulty of making decisions caused by too much information. In this dissertation, we address information overload problem in two separate structured domains, namely, graphs and text.

Graph kernels have been proposed as an efficient and theoretically sound approach to compute graph similarity. They decompose graphs into certain sub-structures, such as subtrees, or subgraphs. However, existing graph kernels suffer from a few drawbacks. First, the dimension of the feature space associated with the kernel often grows exponentially as the complexity of sub-structures increase. One immediate consequence of this behavior is that small, non-informative, sub-structures occur more …

Investigation Of Climate Variability And Climate Change Impacts On Corn Yield In The Eastern Corn Belt, Usa, Ruoyu Wang

Open Access Dissertations

The increasing demand for both food and biofuels requires more corn production at global scale. However, current corn yield is not able to meet bio-ethanol demand without jeopardizing food security or intensifying and expanding corn cultivation. An alternative solution is to utilize cellulose and hemi-cellulose from perennial grasses to fulfill the increasing demand for biofuel energy. A watershed level scenario analysis is often applied to figure out a sustainable way to strike the balance between food and fuel demands, and maintain environment integrity. However, a solid modeling application requires a clear understanding of crop responses under various climate stresses. This …

Energy Transfer And Localization In Molecular Crystals, Mitchell A. Wood

Open Access Dissertations

With the aim of developing new technologies for the detection and defeat of energetic materials, this collection of work was focused on using simulations to characterize materials at extremes of temperature, pressure and radiation. Each branch of the work here is collected by which material response is potentially used as the detectable signal.

Where the chemical response is of interest, this work will explore the possibility of non-statistical chemical reactions in condensed-phase energetic materials via reactive molecular dynamics (MD) simulations. We characterize the response of three unique high energy density molecular crystals to different means of energy input: electric fields …

Zephyr: A Social Psychology-Based Mobile Application For Long-Distance Romantic Partners, Dhiraj Bodicherla

Open Access Theses

Long-distance romantic relationships have become quite common nowadays. With CMC tools advancing day-by-day, their usage among LDRs is proliferating rapidly. Attachment-related anxiety and avoidance can block the ability to enjoy happy relationships. During such situations, remembering happy past moments can be comforting. In this study a mobile chat application that enables LDR couples to reminisce about happy moments was developed. This study primarily focuses on evaluating the usability of this mobile application using survey-based methods. System Usability Scale was considered to discuss the outcome of the study. The overall results provide useful recommendations for further improvements in the design of …

Simulation Of Conservation Practice Effects On Water Quality Under Current And Future Climate Scenarios, Carlington W. Wallace

Open Access Dissertations

Analysis of the effects of implementing different conservation practices, as well as increased levels of conservation practices under existing and projected future climate, will determine if current conservation practice recommendations will be sufficient to maintain soil and water resources. The Soil and Water Assessment Tool (SWAT) was used to study four watersheds of different sizes (CCW = 680 km2, F34 = 183 km2, AXL = 42 km 2 and ALG = 20 km2) located in Northeastern Indiana. The overarching goal of this study was to evaluate the effect of various agricultural practices on runoff and agricultural chemical losses under current …

Homological Properties Of Determinantal Arrangements, Arnold H. Yim

Open Access Dissertations

We study a certain family of hypersurface arrangements known as determinantal arrangements. Determinantal arrangements are a union of varieties defined by minors of a matrix of indeterminates. In particular, we investigate determinantal arrangements using the 2-minors of a 2 × n generic matrix (which can be thought of as natural extensions of braid arrangements), and prove certain statements about their freeness. We also study the topology of these objects. We construct a fibration for the complement of free determinantal arrangements, and use this fibration to prove statements about their homotopy groups. Furthermore, we show that the Poincaré polynomial of the …

End-To-End Security In Service-Oriented Architecture, Mehdi Azarmi

Open Access Dissertations

A service-oriented architecture (SOA)-based application is composed of a number of distributed and loosely-coupled web services, which are orchestrated to accomplish a more complex functionality. Any of these web services is able to invoke other web services to offload part of its functionality. The main security challenge in SOA is that we cannot trust the participating web services in a service composition to behave as expected all the time. In addition, the chain of services involved in an end-to-end service invocation may not be visible to the clients. As a result, any violation of client’s policies could remain undetected. To …

Undergraduate Students' Goals For Chemistry Laboratory Coursework, Brittland K. Dekorver

Open Access Dissertations

Chemistry laboratory coursework has the potential to offer many benefits to students, yet few of these learning goals are realized in practice. Therefore, this study seeks to characterize undergraduate students’ learning goals for their chemistry laboratory coursework. Data were collected by recording video of students completing laboratory experiments and conducting interviews with the students about their experiences that were analyzed utilizing the frameworks of Human Constructivism and Self-Regulated Learning. A cross-sectional sampling of students allowed comparisons to be made among students with varying levels of chemistry experience and interest in chemistry. The student goals identified by this study were compared …

Learning From Minimally Labeled Data With Accelerated Convolutional Neural Networks, Aysegul Dundar

Open Access Dissertations

The main objective of an Artificial Vision Algorithm is to design a mapping function that takes an image as an input and correctly classifies it into one of the user-determined categories. There are several important properties to be satisfied by the mapping function for visual understanding. First, the function should produce good representations of the visual world, which will be able to recognize images independently of pose, scale and illumination. Furthermore, the designed artificial vision system has to learn these representations by itself. Recent studies on Convolutional Neural Networks (ConvNets) produced promising advancements in visual understanding. These networks attain significant …

Is Metabolism Goal-Directed? Investigating The Validity Of Modeling Biological Systems With Cybernetic Control Via Omic Data, Frank T. Devilbiss

Open Access Dissertations

Cybernetic models are uniquely juxtaposed to other metabolic modeling frameworks in that they describe the time-dependent regulation of cellular reactions in terms of dynamic "metabolic goals." This approach contrasts starkly with purely mechanistic descriptions of metabolic regulation which seek to explain metabolic processes in high resolution — a clearly daunting undertaking. Over a span of three decades, cybernetic models have been used to predict metabolic phenomena ranging from resource consumption in mixed-substrate environments to intracellular reaction fluxes of intricate metabolic networks. While the cybernetic approach has been validated in its utility for the prediction of metabolic phenomena, its central feature, …

Effect Of Bioenergy Crops And Fast Growing Trees On Hydrology And Water Quality In The Little Vermilion River Watershed, Tian Guo

Open Access Dissertations

Energy security and sustainability require a suite of biomass crops, including woody species. Short rotation woody crops (SRWCs) such as Populus have great potential as biofuel feedstocks. Quantifying biomass yields of bioenergy crop and hydrologic and water quality responses to growth is important should it be widely planted in the Midwestern U.S. Subsurface tile drainage systems enable the Midwest area to become highly productive agricultural lands, but also create environmental problems like nitrate-N contamination of the water it drains. The Soil and Water Assessment Tool (SWAT) has been used to model watersheds with tile drainage, but the new tile drainage …

Fabrication And Photonics Properties Of Iii-V Semiconductor Nanowire Structures, Tzu-Ging Lin

Open Access Dissertations

III-V semiconductor nanowires (NWs) have shown great potential to be building blocks for optical, optoelectronic, and electronic devices due to their special transverse confinement of electrons and photons along the nanowire axis. In addition, semiconductor nanowires with subwavelength structures exhibit strong optical Mie resonance, making them ideal platforms for realizing novel optical devices, such as extreme solar energy absorbers and broadband light trapping devices. This special 1D optical Mie resonance can be enhanced by using semiconductor-core dielectric-shell (CS) and metal-core semiconductor-shell dielectric-outer shell (CSS) nanowire heterostructures. Those advantages can be even leveraged up by utilizing nanowire arrays, attributing to the …

Optimal Monitoring And Mitigation Of Systemic Risk In Lending Networks, Zhang Li

Open Access Dissertations

This thesis proposes optimal policies to manage systemic risk in financial networks. Given a one-period borrower-lender network in which all debts are due at the same time and have the same seniority, we address the problem of allocating a fixed amount of cash among the nodes to minimize the weighted sum of unpaid liabilities. Assuming all the loan amounts and cash flows are fixed and that there are no bankruptcy costs, we show that this problem is equivalent to a linear program. We develop a duality-based distributed algorithm to solve it which is useful for applications where it is desirable …

Kernels Of Adjoints Of Composition Operators On Hilbert Spaces Of Analytic Functions, Brittney Rachele Miller

Open Access Dissertations

This thesis contains a collection of results in the study of the adjoint of a composition operator and its kernel in weighted Hardy spaces, in particular, the classical Hardy, Bergman, and Dirichlet spaces. In 2006, Cowen and Gallardo-Gutiérrez laid the groundwork for an explicit formula for the adjoint of a composition operator with rational symbol acting on the Hardy space, and in 2008, Hammond, Moorhouse, and Robbins established such a formula. In 2014, Goshabulaghi and Vaezi obtained analogous formulas for the adjoint of a composition operator in the Bergman and Dirichlet spaces. While it is known that the kernel of …

Crop Modeling For Assessing And Mitigating The Impacts Of Extreme Climatic Events On The Us Agriculture System, Zhenong Jin

Open Access Dissertations

The US agriculture system is the world’s largest producer of maize and soybean, and typically supplies more than one-third of their global trading. Nearly 90% of the US maize and soybean production is rainfed, thus is susceptible to climate change stressors such as heat waves and droughts. Process-based crop and cropping system models are important tools for climate change impact assessments and risk management. As data- science is becoming a new frontier for agriculture growth, the incoming decade calls for operational platforms that use hyper-local growth monitoring, high-resolution real-time weather and satellite data assimilation and cropping system modeling to help …

Climate Change And Hazardous Convective Weather In The United States: Insights From High-Resolution Dynamical Downscaling, Kimberly A. Hoogewind

Open Access Dissertations

Global climate model (GCM) projections increasingly suggest that large-scale environmental conditions favorable for hazardous convective weather (HCW) may increase in frequency in the future due to anthropogenic climate change. However, this storm environment-based approach is undoubtedly limited by the assumption that convective-scale phenomena will be realized within these environments. The spatial resolution of GCMs remains much too coarse to adequately represent the scales at which severe convective storms occur, including processes that may lead to storm initiation. With the advancement of computing resources, however, it has now become feasible to explicitly represent deep convective storms within a high-resolution regional climate …

Energy Efficiency In Data Collection Wireless Sensor Networks, Miquel Andres Navarro Patino

Open Access Dissertations

This dissertation studies the problem of energy efficiency in resource constrained and heterogeneous wireless sensor networks (WSNs) for data collection applications in real-world scenarios. The problem is addressed from three different perspectives: network routing, node energy profiles, and network management. First, the energy efficiency in a WSN is formulated as a load balancing problem, where the routing layer can diagnose and exploit the WSN topology redundancy to reduce the data traffic processed in critical nodes, independent of their hardware platform, improving their energy consumption and extending the network lifetime. We propose a new routing strategy that extends traditional cost-based routing …

Monotonicity Formulas For Diffusion Operators On Manifolds And Carnot Groups, Heat Kernel Asymptotics And Wiener's Criterion On Heisenberg-Type Groups, Kevin L. Rotz

Open Access Dissertations

The contents of this thesis are an assortment of results in analysis and subRiemannian geometry, with a special focus on the Heisenberg group Hn, Heisenbergtype (H-type) groups, and Carnot groups.

As we wish for this thesis to be relatively self-contained, the main definitions and background are covered in Chapter 1. This includes basic information about Carnot groups, Hn, H-type groups, diffusion operators, and the curvature dimension inequality.

Chapter 2 incorporates excerpts from a paper by N. Garofalo and the author, [42]. In it, we propose a generalization of Almgren’s frequency function N : (0, 1) → R for solutions to …

Finite Dimensional Approximations And Deformations Of Group C*-Algebras, Andrew James Schneider

Open Access Dissertations

Quasidiagonality is a finite-dimensional approximation property of a C*-algebra which indicates that it has matricial approximations that capture the structure of the C*-algebra. We investigate when C*-algebras associated to discrete groups have such a property with particular emphasis on finding obstructions. In particular, we point out that groups with Kazhdan's Property (T) and only finitely many unitary equivalence classes of finite dimensional representations do not produce quasidiagonal C*-algebras. We then observe and note interactions with Property (T) and other approximation properties.

Property (QH) is a related but stronger approximation property with deep connections to E-Theory and …

Direct Drug Screening And Lipid Profiling Using Ambient Mass Spectrometry, Yuan Su

Open Access Dissertations

Mass spectrometry (MS) stands in an outstanding position in analysis of biological specimens owing to its abundant structural information, high accuracy, incomparable sensitivity, high speed, and the large variety of its applications. The ion source, an instrumental part for converting the analyte into ions, has played an important role in analyzing biological specimens by MS. However, the performance of conventional spray-based ionization methods always suffers from chemical interferences derived from complex biological matrices. A series of sample extraction, purification, and separation steps is required before the ionization, so as to ensure excellent performance of MS analysis. In order to simplify …

Double Optical Feedback And Pt-Symmetry Breaking Induced Nonlinear Dynamics In Semiconductor Lasers, Joseph S. Suelzer

Open Access Dissertations

A central aim of this research is to probe the nonlinear dynamics that arise in a semiconductor laser due to optical feedback. We investigate two schemes of optical feedback. The first scheme subjects the laser to optical feedback from two external cavities (or two loops), wherein each cavity contains a spectral filter. Using two filtered optical feedbacks, we experimentally demonstrate the ability to elicit and control unique dynamics in the optical emission frequency (wavelength) of the laser. These results are compared to a deterministic model describing the evolution of the complex electric field and carrier density of the laser. As …

Present Day Plate Boundary Deformation In The Caribbean And Crustal Deformation On Southern Haiti, Steeve Symithe

Open Access Dissertations

The Caribbean plate and its boundaries with North and South America, marked by subduction and large intra-arc strike-slip faults, are a natural laboratory for the study of strain partitioning and interseismic plate coupling in relation to large earth- quakes. In this work, I use the available campaign and continuous GPS measurements in the Caribbean to derive a regional velocity field expressed in a consistent reference frame. I use this velocity field as input to a kinematic model where surface velocities result from the rotation of rigid blocks bounded by locked faults accumulating inter- seismic strain, while allowing for partial locking …

Behavioral Responses And Policy Evaluation: Revisiting Water And Fuel Policies, Shanxia Sun

Open Access Dissertations

In my dissertation, I examine how policies regulating agricultural production and clean technology impact the environment. I focus on policies affecting water depletion, water pollution, and fuel consumption. I assess their cost-effectiveness by modeling and quantifying the behavioral responses of farmers and households.

My first essay focuses on decreasing groundwater depletion through increasing irrigation efficiency in Mexico. I quantify the impacts of different sources of inefficiency on groundwater extraction, and I evaluate the effectiveness of alternative policies that aim to reduce the over-extraction of groundwater. I find that mechanisms of electricity cost-sharing implemented in many wells have a sizable impact …

A History Of African And South American Basins, Rebecca A. Bobick

Open Access Theses

As hydrocarbon development in Africa and South America continues to expand, understanding the geologic evolution as well as the geologic symmetry of each of the continent's coastal basins grows increasingly important. Unfortunately, there's currently no comprehensive database that contains the stratigraphic record, depositional environments, and tectonic evolution available for either Africa or South America. Therefore, the goal of my research is to create an extensive datapack and guide booklet for Africa's major sedimentary basins, complete the South America datapack that's currently being constructed, and correlate the western African conjugate basins to the eastern South American conjugate basins. To accomplish this, …

Social Customer Relationship Management In Higher Education, Victorian A. Farnsworth

Open Access Theses

Customer Relationship Management is a concept that has become a requirement for any successful entity to attract and retain desired constituents. It is a set of processes and tools that help track, analyze, and act upon customer related data. Over the last decade, the toolsets have evolved to include social media as another source of information and connection. Nowhere is this information and connection more important than in higher education where globalization and tighter budgets have created a competitive market. This research evaluated the use of this most recent social toolset and its effectiveness in a higher education institution, all …

Purification And Preparation Of Intrinsically Disordered Proteins For Nmr Spectroscopy, Kyle Chamberlain

Open Access Theses

NMR spectroscopy has recently become a promising field for protein characterization and dynamic studies. As the technology and pulse sequences improve for tracking proteins, a greater demand for developing effective purification protocols to produce NMR grade protein samples have arisen. This thesis explores two proteins: histone H4 tail and Mucin 1; Two very different proteins that require different methods of expression and purification to achieve a high enough yield for NMR analysis. H4 is a water soluble protein that weighs ~2.7 kDa, and has no extinction coefficient. Since the protein is too small for many methods of expression and purification, …

Hardware Accelerated Redundancy Elimination In Network System, Kelu Diao

Open Access Theses

With the tremendous growth in the amount of information stored on remote locations and cloud systems, many service providers are seeking ways to reduce the amount of redundant information sent across networks by using data de-duplication techniques. Data de-duplication can reduce network traffic without the loss of information, and consequently increase available network bandwidth by reducing redundant traffic. However, due to the heavy computation required for detecting and reducing redundant data transmission, de-duplication itself can become a bottleneck in high capacity links. We completed two parts of work in this research study, Hardware Accelerated Redundancy Elimination in Network Systems (HARENS) …

Extracting Cng Tls/Ssl Artifacts From Lsass Memory, Jacob M. Kambic

Open Access Theses

Currently, there is no publicly accessible, reliable, automated way to forensically decrypt Secure Socket Layer (SSL)/Transport Layer Security (TLS) connections that leverage ephemeral key negotiations as implemented by the modern Windows operating system. This thesis explores the Local Security Authority Sub-System (LSASS) process used for Key Isolation within the Windows 10 operating system in pursuit of identifying artifacts that would allow a solution to that problem, along with any other connection artifacts that could provide forensic value. The end result was the identication of TLS/SSL secrets from the key exchange and contextual artifacts that provide identication of the other party …

User-Centric Workload Analytics: Towards Better Cluster Management, Suhas Raveesh Javagal

Open Access Theses

Effective management of computing clusters and providing a high quality customer support is not a trivial task. Due to rise of community clusters there is an increase in the diversity of workloads and the user demographic. Owing to this and privacy concerns of the user, it is difficult to identify performance issues, reduce resource wastage and understand implicit user demands. In this thesis, we perform in-depth analysis of user behavior, performance issues, resource usage patterns and failures in the workloads collected from a university-wide community cluster and two clusters maintained by a government lab. We also introduce a set of …

Economic And Environmental Impacts Of A Hypothetical Global Gmo Ban, Harrison H. Mahaffey

Open Access Theses

The objective of this research is to assess the global economic and greenhouse gas emission impacts of GMO crops. This is done by modeling two counterfactual scenarios and evaluating them apart and in combination. The first scenario models the impact of a global GMO ban. The second scenario models the impact of increased GMO penetration. The focus is on the price and welfare impacts, and land use change greenhouse gas (GHG) emissions associated with GMO technologies. Much of the prior work on the economic impacts of GMO technology has relied on a combination of partial equilibrium analysis and econometric techniques. …