Digital Commons Network^™

Robust L1-Norm Singular-Value Decomposition And Estimation, Duc H. Le

Theses

Singular-Value Decomposition (SVD) is a ubiquitous data analysis method in engineering, science, and statistics. Singular-value estimation, in particular, is of critical importance in an array of engineering applications, such as channel estimation in communication systems, EMG signal analysis, and image compression, to name just a few. Conventional SVD of a data matrix coincides with standard Principal-Component Analysis (PCA). The L2-norm (sum of squared values) formulation of PCA promotes peripheral data points and, thus, makes PCA sensitive against outliers. Naturally, SVD inherits this outlier sensitivity. In this work, we present a novel robust method for SVD based on a L1-norm (sum …

Graph Arrowing: Constructions And Complexity, Zohair Raza Hassan

Theses

Graph arrowing is concerned with determining which monochromatic subgraphs are unavoidable when coloring a given graph. There are two main avenues of research concerning arrowing: finding extremal Ramsey/Folkman graphs and categorizing the complexity of arrowing problems. Both avenues have been studied extensively for decades. In this thesis, we focus on graph arrowing problems where one of the monochromatic subgraphs being avoided is the path on three vertices, denoted as P3. Our main contributions involve computing Folkman numbers by generating graphs up to 13 vertices and proving the coNP-completeness of some arrowing problems using a novel reduction framework geared towards avoiding …

Learning Multi-Step Robotic Manipulation Tasks Through Visual Planning, Sulabh Kumra

Theses

Multi-step manipulation tasks in unstructured environments are extremely challenging for a robot to learn. Such tasks interlace high-level reasoning that consists of the expected states that can be attained to achieve an overall task and low-level reasoning that decides what actions will yield these states. A model-free deep reinforcement learning method is proposed to learn multi-step manipulation tasks. This work introduces a novel Generative Residual Convolutional Neural Network (GR-ConvNet) model that can generate robust antipodal grasps from n-channel image input at real-time speeds (20ms). The proposed model architecture achieved a state-of-the-art accuracy on three standard grasping datasets. The adaptability of …

Towards Efficient Lifelong Machine Learning In Deep Neural Networks, Tyler L. Hayes

Theses

Humans continually learn and adapt to new knowledge and environments throughout their lifetimes. Rarely does learning new information cause humans to catastrophically forget previous knowledge. While deep neural networks (DNNs) now rival human performance on several supervised machine perception tasks, when updated on changing data distributions, they catastrophically forget previous knowledge. Enabling DNNs to learn new information over time opens the door for new applications such as self-driving cars that adapt to seasonal changes or smartphones that adapt to changing user preferences. In this dissertation, we propose new methods and experimental paradigms for efficiently training continual DNNs without forgetting. We …

Lightness, Brightness, And Transparency In Optical See-Through Augmented Reality, Lili Zhang

Theses

Augmented reality (AR), as a key component of the future metaverse, has leaped from the research labs to the consumer and enterprise markets. AR optical see-through (OST) devices utilize transparent optical combiners to provide visibility of the real environment as well as superimpose virtual content on top of it. OST displays distinct from existing media because of their optical additivity, meaning the light reaching the eyes is composed of both virtual content and real background. The composition results in the intended virtual colors being distorted and perceived transparent. When the luminance of the virtual content decreases, the perceived lightness and …

Functional Evolutionary Adaptation Of Binding Dynamics In The Sars-Cov-2/Ace2 Interface From Bats To Humans, Madhusudan Rajendran

Theses

The COVID-19 pandemic highlights the substantial public health, economic, and societal consequences of virus spillover from a wildlife reservoir. Widespread human transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) also presents a new set of challenges when considering viral spillover from people to naïve wildlife and other animal populations. Here, we used molecular dynamic (MD) simulations to understand the transmission of the SARS-CoV-2 virus from bats to humans and investigate the evolution of the various human variants. More specifically, we used MD simulations to understand the atomic fluctuation dampening at the receptor-binding domain (RBD)/ angiotensin-converting enzyme 2 (ACE2) interface …

Reflectance And Emittance Spectra Of Intimately Mixed And Layered Media, Charles A. Tabor Jr

Theses

The remote characterization of intimately mixed and layered media is a com- plicated and yet critical aspect of understanding the natural and human ac- tivities that induce the mixing and layering of surface media. The study of this environment is aided by two Hapke models that attempt to address these challenges in the context of reflectance spectroscopy. The Hapke mixing model predicts the spectra of intimate mixtures based upon end member spectra and known geophysical parameters but has not been evaluated over a wide range of non-powder mixtures which are common in littoral environments. The Hapke model for the diffusive …

Sustainability In Design: The Exploration Of Using Digital Design As A Tool To Promote Environmental Conservation And Sustainable Practice, Kaitlyn Maxwell

Theses

The final website deliverable functions not only as a means of presentation, but as a jumping off point for digital designers to build off of, using the carefully curated resources and informational findings that are included in, and crafted specifically for, this project. By focusing on three main aspects of how to answer the research question 1) creating awareness, 2) making a case for caring, and 3) effective messaging methods, a framework has been created that the audience can expand upon without being overwhelmed by a question with many potential routes to travel down. A digital designer can promote sustainable …

Multi-Scale Architectures For Human Pose Estimation, Bruno Artacho

Theses

In this dissertation we present multiple state-of-the-art deep learning methods for computer vision tasks using multi-scale approaches for two main tasks: pose estimation and semantic segmentation. For pose estimation, we introduce a complete framework expanding the fields-of-view of the network through a multi-scale approach, resulting in a significant increasing the effectiveness of conventional backbone architectures, for several pose estimation tasks without requiring a larger network or postprocessing. Our multi-scale pose estimation framework contributes to research on methods for single-person pose estimation in both 2D and 3D scenarios, pose estimation in videos, and the estimation of multiple people’s pose in a …

Application Of Natural Radioactivity For Hydrogeological And Environmental Assessment Of Groundwater In Ras Alkhaimah, Uae, Mohammed Nasser Abdullah Al-Saqri

Theses

Groundwater includes a certain concentration of natural radioactive isotopes of uranium (U) and its decay products (daughters) like radon (Rn). Defining the concentration levels, spatial distribution, and possible environmental impact of these isotopes in groundwater is vital for sustainable groundwater resources in the United Arab Emirates (UAE). This dissertation focuses on documenting the distribution and determining the probable environmental impact and sources of Uranium-235 (²³⁵U), Uranium-238 (²³⁸U), and Radon-222 (²²²Rn) in groundwater in the Northern part of the UAE and specifically in the Wadi Al Bih aquifer in Ras Al Khaimah Emirate. The sampled …

Non-Adiabatic Perturbations And Non-Gaussianity During Inflation: Affine Gravity Approach, Isaac Bamwidhi

Theses

This thesis is concerned with providing a complete study of non-Gaussianity and entropy perturbations that are sourced by multiple fields nonminimally coupled to gravity. The study will be performed in the framework of the two important formulations of gravity, namely: purely metric (general relativity) and purely affine formulation – where the metrical structure results from the dynamics of the spacetime affine connection. We shall employ a covariant formalism in our framework and demonstrate that it leads to a curved field space which can produce a conspicuous departure from the purely metric gravity. This work is expected, not only to derive …

Finitely Generated Modules Over A Principal Ideal Domain, Mariam Mutawa Meshaab Shemal Al-Dhaheri

Theses

This thesis covers the main theory of modules: modules, submodules, cosets, quotient modules, homomorphisms, ideals, direct sums, and some related topics. Using these notions, a theorem on the structure of finitely generated modules over domains of principal ideals is proved. As an application of this theorem, the theory of the structure of normal forms of matrices over various fields is presented.

The Correlation Between The Effects Of Strain And Stochiometric Coefficient On The Magnetic Properties Of Srsno₃ And Sr₃Sno, Amal Sameh Kashcoul

Theses

Perovskites (ABX₃) are one of the most prominent families of crystalline alloys have received excellent research attention globally because of their diverse multi-functionalities and the interesting physics underpinning them. On the other hand, antiperovskites (X₃BA) are electronically inverted perovskite derivates, yet they are not an insignificant class of functional materials. Antiperovskites, inheriting the flexible structural characteristics of perovskites and rich in cations at X sites, display unusual chemical and physical properties. The SrSnO₃ is a distinctive perovskite oxide in that it possesses a higher electron conductivity despite its sizeable optical band gap. This dissertation has …

Bandgap Tuning Of Mose2 And Wse2 Monolayers Through Alloying And Substitution: An Ab Initio Study, Shahida Maqsood

Theses

2D materials attracted considerable interest in the research community following the first report in 2004 on the preparation of graphene by simple micromechanical exfoliation of highly oriented pyrolytic graphite. For example, single-layer Molybdenum Di selenide (MoSe₂) and Tungsten Di selenide (WSe₂) transistors with on/off ratios of 108 and ultra-low standby power dissipation were demonstrated. Graphene electrodes have been used to develop fully transparent resistive memories to suppress unwanted surface effects that occur in oxide memory devices. Photodetectors based on MoSe₂ with few layers have shown excellent photodetection properties. Phototransistors based on WSe₂ monolayers exhibit …

Convection In High-Mass And Low-Mass Common Envelopes, Emily C. Wilson

Theses

While isolated stars evolve in fairly predictable ways, the evolution of a binary star (i.e., a pair of stars) is not as well understood. Many close binary systems undergo a phase of evolution wherein one star engulfs the other such that both stars share a common stellar envelope. During this phase, the orbital distance between the two stars rapidly shrinks by a factor of 100-1000 in approximately 1-10 years. As a result of this so-called “inspiral,” the companion deposits energy into the envelope until the shared envelope itself becomes gravitationally unbound and is ejected from the system. The efficiency with …

Technology Assisted Review Of Legal Documents, Malik Umar Hassan

Theses

A legal prediction-based approach will help judges and solicitors to take judicial decisions on current cases, which are going on in courts, and make predictions on new cases on the basis of existing references and judgments. This model also helps law students learn about legal references. This application was developed specifically for the “Supreme Court of Pakistan (SCP)” and the “Pakistan Bar Council (PBC)” to expedite their judgments and provide legal guidance to lawyers based on historical data and constitutions.

Predicting Energy Consumption During Expo 2020, Rashed Waleed Albishre

Theses

The art of the Expo event is the bloom in the economy of the country where it is hosted along with the collaboration among the various areas of the country. Dubai availed the privilege of hosting Expo 2020. Dubai being a center of attention for tourist attraction and the growth in its economy, took pride in hosting the event while working on themes and ways to make the event stand out. Expo is known to bring visitors from around the world to one country for a duration of six months where the visitors are provided with an opportunity to enjoy …

Reproducing Kernel Method For Solving Fuzzy Initial Value Problems, Qamar Kamel Dallashi

Theses

In this thesis, numerical solution of the fuzzy initial value problem will be investigated based on the reproducing kernel method. Problems of this type are either difficult to solve or impossible, in some cases, since they will produce a complicated optimized problem. To overcome this challenge, reproducing kernel method will be modified to solve this type of problems. Theoretical and numerical results will be presented to show the efficiency of the proposed method.

Scalable Probabilistic Model Selection For Network Representation Learning In Biological Network Inference, K C Kishan

Theses

A biological system is a complex network of heterogeneous molecular entities and their interactions contributing to various biological characteristics of the system. Although the biological networks not only provide an elegant theoretical framework but also offer a mathematical foundation to analyze, understand, and learn from complex biological systems, the reconstruction of biological networks is an important and unsolved problem. Current biological networks are noisy, sparse and incomplete, limiting the ability to create a holistic view of the biological reconstructions and thus fail to provide a system-level understanding of the biological phenomena. Experimental identification of missing interactions is both time-consuming and …

The Effect Of Marine Snow Particle Distribution On The Foraging Behavior Of Calanus Pacificus, Elena Beckhaus

Theses

Marine snow is a major component of the biological pump, through which carbon is exported to the deep ocean. The sinking of marine snow can be disrupted by organisms, including many species of zooplankton that ingest or break up aggregates. These processes can have important impacts on planktonic food web dynamics and carbon export. Marine snow can have vertically patchy distributions, occurring in thin layers, which may further affect interactions with zooplankton. In this lab-based study, we examined how the presence of a marine snow layer affects copepod behavior and ingestion.

We conducted a series of experiments in which copepods …

Design And Implementation Of Photovoltaic Energy Harvesting Automaton, Iskandar Askarov

Theses

Global domestic electricity consumption has been rapidly increasing in the past three decades. In fact, from 1990 to 2020, consumption has more than doubled from 10,120 TWh to 23,177 TWh [1]. Moreover, consumers have been turning more towards clean, renewable energy sources such as Photovoltaic. According to International Energy Agency, global Solar power generation alone in 2019 has reached almost 3% [4] of the electricity supply. Even though the efficiency of photovoltaic panels has been growing, presently, the highest efficiency solar panels available to an average consumer range only from 20%-22% [14]. Many research papers have been published to increase …

Genomic Changes Associated With Transitions To Heterospory And Genome Downsizing In Land Plants, Rijan R. Dhakal

Theses

Green plants, ubiquitous and essential in the biosphere, have two reproductive life cycles: heterosporous and homosporous. Heterosporous plants are generally seen more often in daily life and tend to be the source of staple foods. Heterosporous reproduction has evolved at least 11 times from ancestral homosporous lineages. Heterospory, presumed to have selective advantages, has a perplexing correlation with chromosome numbers. Here I have used novel data, tools, and methodology to discover 19, so far unknown, gene families, with the potential to explain the correlation between the reproductive life cycle in green plants and chromosome numbers. The discovery of these gene …

Nonlinear Adaptive Sliding Mode Control With Application To Quadcopters, Ryan Mathewson

Theses

Nonlinear Adaptive Sliding Mode Control (NASMC) has the capability to adequately control a system whose parameters are unknown to the controller designer. Conventional model-based controllers require a mathematical dynamic model of the system with known parameters. These are normally determined by extensive system identification experiments which are expensive and time consuming to perform. In this thesis, a NASMC approach is proposed that does not require known system parameters. Using NASMC, a controller designer can skip the system parameter identification and fast forward to the control implementation. In addition, once a NASMC controller is derived for a quadcopter, the same controller …

Thermal Model Of A Centrifugal Nuclear Thermal Propulsion System, Jacob T. Keese

Theses

A numerical model was developed to study the heat transfer within the reactor of a Centrifugal Nuclear Thermal Propulsion system wherein liquid uranium heats hydrogen gas via direct-contact heat transfer. This one-dimensional, steady-state model treats the liquid uranium annulus of the centrifugal reactor as a conducting solid with internal energy generation and includes models of convection on the outside of the reactor, nonuniform energy generation from a detailed neutronics calculation, and models of bubble velocity and heat transfer. Results for three annulus geometries were compared for a variety of run conditions with the goal of maximizing the propellant output temperature …

Adaptive Data Association Using Multiple Hypothesis Tracker For Space Object Tracking, Thibault Richard

Theses

There are thousands of objects in space with only a few sensors. Also when multiple objects are observed by a sensor, there is often an ambiguity of which measurement belongs to which object. This research intends to find a solution to this data association problem by developing a joint data association and orbit determination approach to adaptively assist the data association problem in tracking all the objects as accurately as possible. The solution studied throughout this thesis is the Multiple Hypothesis Tracker, a structure that comprises all the observations combinations. Then, a gating system of initial orbit determination, orbit determination …

Assess, Address, Progress: An Online Approach To Evaluate And Develop Teacher Education Students’ Numeracy Capability, Kate Hartup

Theses

For as long as numeracy has been assessed as a major domain in Australia (since 2003), Australian school students’ numeracy levels have been declining (Thomson et al., 2019). This decline is evident despite it being a national requirement for teachers to teach numeracy skills across all subject areas at all year levels (Australian Curriculum and Reporting Authority (ACARA), n.d.). Although there are several definitions of numeracy, fundamentally it is the application of mathematics and the ability to interpret and utilise mathematical information (Australian Council for Educational Research (ACER), 2017). Given that teachers’ mathematical knowledge has been shown to affect their …

The Virtue Of Appropriate Transparency: Research Psychology And The Replication Crisis, Barry Mannolini-Winwood

Theses

I argue that one step toward addressing the replication crisis in psychology is through the application of appropriate transparency in research communication. Drawing upon virtue epistemology, I propose that appropriate transparency can be defined as a contextually informed point between understatement and overstatement. As such, I contend that judging appropriate transparency in research psychology requires a shared research design nomenclature (RDN). As researchers’ definitions of terms related to research psychology are not necessarily identical between individuals, it is beneficial to use transparent definitions of pivotal concepts to facilitate effective communication between researchers and their audience. However, the boundaries of appropriate …

Developing Mathematical Identities: Australian Children’S Gendered Constructs In The First Formal Year Of School, Rachelle Glynn

Theses

Researchers have been intrigued by the dichotomy of similar achievement levels between boys and girls but disparate mathematical attitudes, which show that girls are much less likely to enjoy or engage with mathematics or choose professions involving mathematics (Kyriacou & Goulding, 2006; Vale, 2008). Although studies have explored differences in boys' and girls' perceptions of their mathematical identity from age seven, there has not been research conducted on students as they begin school to see what gendered perceptions they bring to their mathematical learning. This study seeks to answer the question: How are girls’ and boys’ mathematical identities being informed …

The Process And Impact Of A Catholic School Amalgamation: A Mixed Method, Single Case Study, Stephen Gough

Theses

This research provides an investigative analysis of the impact of a large-scale change process involving the amalgamation of two long-standing Catholic schools in a capital city of Australia. The study explores how a change process impacted staff, student and parent stakeholders within the initial year of a school amalgamation by examining Catholic school life and culture, student learning and wellbeing, the physical learning environment, and leadership and administration. The objective is to better understand the process and the impact of the change that took place during the amalgamation, in order to further inform the planning and leading of future Catholic …

Federal Fashion: Uniform Modification, Self-Expression, And The Union Infantry Officer Of The American Civil War, Clayton Davis

Theses

The military uniforms of the American Civil War, particularly on the Union side, varied tremendously through time and location. There were an endless number of combinations􀂲myriad boots and hats, coats and jackets, insignias, and trousers. That was true for officers, especially commissioned officers, who exercised the greatest aesthetic freedom. Scattered works have broached the topic of officer uniforms, especially those of Confederate officers, though their Union counterparts have gone under the microscope also. Invariably, these works include non-regulation uniforms, either compiled by officers from separate pieces or handmade by one of the hundreds of tailors working across the nation. However, …