Physical Sciences and Mathematics Commons^™

On A Fundamental Polyhedron Of A Hyperbolic Cone-Manifold, Lilya Grunwald, Aydos Qutbaev

Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences

In this paper we propose to consider two different solutions having a common problem of establishing hyperbolic structure on a 3-manifold. Under the consideration will be a cone 3-manifold with underlying space as a 3-sphere and a singular set nested in it. Furthermore, this paper is divided into two cases: a singular set as the 3₁ knot with a bridge and a singular set as the 6₁³ link. The hyperbolic space $H³ for the analytical examination in the first case will be a hyperboloid model, in the second using the upper-half space model. To show that …

Usual, Quadratic And Cubic Numerical Ranges Corresponding To A $3\Times 3$ Operator Matrices, Mubina Sharipova

Bulletin of National University of Uzbekistan: Mathematics and Natural Sciences

In the present paper we consider bounded self-adjoint 3x3 operator matrices A. An alternative formula for the calculating the cubic numerical range of the operator matrices A is derived. The components of the quadratic numerical range with respect to the expansion of the Hilbert space are found.

The Facile Preparation Of Bis(Imino)Pyridine Complexes Via Mechanochemistry And Inorganic Synthons Via Benign Reductants, Thomas Shaw

Electronic Theses and Dissertations, 2020-2023

This thesis is comprised of two key themes: (i) leveraging mechanochemical synthetic methods for the green preparation of bis(imino)pyridine ligands and associated first row transition metal coordination complexes, and (ii) the preparation and characterization of both historic and novel mid-valent inorganic synthons via the use of dimethylphenylsilane as a stoichiometric reducing agent. The first portion of this thesis highlights the utilization of solvent-free vibratory ball-milling in lieu of traditional, solvent-based refluxes. A variety of both bis(imino)pyridine ligands and complexes were formed in drastically reduced timeframes with solvent-economical work-up procedures. This methodology was also leveraged for the isolation of acetyl(imino)pyridine ligands …

Torward Real-World Cross-View Image Geo-Localization, Sijie Zhu

Electronic Theses and Dissertations, 2020-2023

Cross-view image geo-localization aims to determine the locations of street-view query images by searching in a GPS-tagged reference image database from aerial view. One fundamental challenge is the dramatic view-point/domain difference between the street-view query images and aerial-view reference images. Recent works have made great progress on bridging the domain gap with advanced deep learning techniques and geometric prior knowledge, i.e. the query is aligned at the center of one aerial-view reference image (spatial alignment) and the orientation relationship between the two views is known (orientation alignment). However, such prior knowledge of the geometry correspondence of the two views is …

Recommendations For Sustainable Tourism In Patagonia: An Exploratory Analysis Of Sustainable Tourism In Costa Rica, The Nordic Region, And Thailand’S Communities, Julia K. Lowery

Undergraduate Honors Theses

This thesis explores different levels of governance and its role towards actualizing sustainable tourism in Patagonia. With the growing threat of climate change, international destinations such as Patagonia are looking to continue building their tourism industries in a sustainable way. Through analyzing case studies of national governance in Costa Rica, multi-national governance in the Nordic region, and community-based tourism in Thailand, we can better understand how each form of governance has the potential to create a sustainable tourism industry. With this understanding of successful governance in my case studies, as well as understanding the historical and political forces that have …

Full-Text Search Using Elasticsearch, Akash Shrestha

Culminating Experience Projects

Search engines have changed the way we use the internet. They can search or filter out relevant and valuable content of interest to the users. But many of the applications we use today lack search or are just poor. So how can we leverage the same power of search engines in our applications? This project aims to look at “Full-Text Search” which allows us to do a text-based search in text-intensive data. The search will be performed by matching any, or all words of the query exactly or with some relevancy against the indexes created by the searching tool. The …

Multi-Plane Light Conversion: Devices And Applications, Yuanhang Zhang

Electronic Theses and Dissertations, 2020-2023

Multi-plane light conversion (MPLC) has recently been developed as a versatile tool for manipulating spatial distributions of the optical field through repeated phase modulations. An MPLC Device consists of a series of phase masks separated by free-space propagation. It can convert one orthogonal set of beams into another orthogonal set through unitary transformation, which is useful for a number of applications. In telecommunication, for example, mode-division multiplexing (MDM) is a promising technology that will enable continued scaling of capacity by employing spatial modes of a single fiber. MPLC has shown great potential in MDM devices with ultra-wide bandwidth, low insertion …

Low-Resource Machine Learning Techniques For The Analysis Of Online Social Media Textual Data, Toktam Amanzadeh Oghaz

Electronic Theses and Dissertations, 2020-2023

Low-resource and label-efficient machine learning methods can be described as the family of statistical and machine learning techniques that can achieve high performance without needing a substantial amount of labeled data. These methods include both unsupervised learning techniques, such as LDA, and supervised methods, such as active learning, each providing different benefits. Thus, this dissertation is devoted to the design and analysis of unsupervised and supervised techniques to provide solutions for the following problems: Unsupervised narrative summary extraction for social media content, Social media text classification with Active Learning (AL), Investigating restrictions and benefits of using Curriculum Learning (CL) for …

Advanced Deep Learning Methodologies For Deepfake Detection, Aminollah Khormali

Electronic Theses and Dissertations, 2020-2023

The recent advances in the field of Artificial Intelligence (AI), particularly Generative Adversarial Networks (GANs) and an abundance of training samples along with robust computational resources have significantly propelled the field of AI-generated fake information in all kinds, e.g., deepfakes. Deepfakes are among the most sinister types of misinformation, posing large-scale and severe security and privacy risks targeting critical governmental institutions and ordinary people across the world. The fact that deepfakes are AI-generated digital content and not actual events captured by a camera implies that they still can be detected using advanced AI models. Although the deepfake detection task has …

Dynamic Rbi With Central Difference Method Approach In Calculation Of Uniform Corrosion Rate: A Casestudy On Gas Pipelines, M.Riefqi Dwi Alviansyah, Fernanda Hartoyo, Zahra Nadia Nurullia, Ari Kurniawan

Journal of Materials Exploration and Findings

The oil and gas industry generally uses a piping system to drain fluids. Even though the pipes used have been well designed, the use of pipes as a means of fluid transportation still provides the possibility of failure that can occur at any time, one of which is due to uniform corrosion. The use of standard Risk Based Inspection (RBI) according to the API RBI 581 document has been widely used to anticipate potential failures to pipe components. The use of standard RBI can reduce the risk of failure significantly. Because the standard RBI considers the component risk value to …

Federated Learning And Applications In Cybersecurity, Ani Sreekumar

Cybersecurity Undergraduate Research Showcase

Machine learning is a subfield of artificial intelligence that focuses on making predictions about some outcome based on information from a dataset. In cybersecurity, machine learning is often used to improve intrusion detection systems and identify trends in data that could indicate an oncoming cyber attack. Data privacy is an extremely important aspect of cybersecurity, and there are many industries that have more demanding laws to ensure the security of user data. Due to these regulations, machine learning algorithms can not be widely utilized in these industries to improve outcomes and accuracy of predictions. However, federated learning is a recent …

Contribution To Data Science: Time Series, Uncertainty Quantification And Applications, Dhrubajyoti Ghosh

Arts & Sciences Electronic Theses and Dissertations

Time series analysis is an essential tool in modern world statistical analysis, with a myriad of real data problems having temporal components that need to be studied to gain a better understanding of the temporal dependence structure in the data. For example, in the stock market, it is of significant importance to identify the ups and downs of the stock prices, for which time series analysis is crucial. Most of the existing literature on time series deals with linear time series, or with Gaussianity assumption. However, there are multiple instances where the time series shows nonlinear trends, or when the …

Quasiparticle And Excitonic Effects In Two-Dimensional Van Der Waals Materials, Linghan Zhu

Arts & Sciences Electronic Theses and Dissertations

Since their discovery, low dimensional van der Waals materials have attracted increasing research interests. They serve as ideal platforms to study novel physics in reduced-dimensional systems, and are critical in nowadays’ nanotechnology applications. Due to the reduced dielectric screening in low dimensions, strong excited state properties dictate their electronic, transport and optical properties, the study of which calls for a description of the many-particle interactions beyond the traditional density functional theory. This is where the many-body perturbation theory comes into play. In this thesis, I will present a comprehensive study of the quasiparticle and excitonic properties of a variety of …

A Synthesis-Based Approach To The Study Of Fe(Ii) Oxidation In Smectites, Robert Joe Kupper Ii

Arts & Sciences Electronic Theses and Dissertations

Smectite clay minerals are present in diverse environments on Earth as a major product of silicate weathering. Although smectites are compositionally varied, they almost always incorporate iron. Iron-bearing smectites are an important component of the biogeochemical iron cycle, serving as a major iron fraction in many soils and altered rocks as well as participating in redox reactions within the surrounding environment. Iron incorporates into smectites in the ferric [Fe(III)] form at the modern, oxygenated surface of Earth but clays forming in anoxic settings instead incorporate ferrous iron [Fe(II)]. Owing to their ubiquity at the surface of the modern Earth, the …

Fourier Acceleration In The Linear Sigma Model, Cameron Cianci

Honors Scholar Theses

The linear sigma model is a low energy effective model of Quantum Chromodynamics. This model mimics the breaking of chiral symmetry both spontaneously and explicitly through the quark condensate and pion mass matrix respectively. Fourier acceleration is a method that can be implemented in the Hybrid Monte-Carlo algorithm which decreases autocorrelations due to critical slowing down through tuning the mass parameters in the HMC algorithm. Fourier acceleration is applied to the linear sigma model with a novel mass estimation procedure, by assuming the modes behave approximately like simple harmonic oscillators. The masses are chosen by sampling the expectation values of …

Kernel Estimation Of Spot Volatility And Its Application In Volatility Functional Estimation, Bei Wu

Arts & Sciences Electronic Theses and Dissertations

It\^o semimartingale models for the dynamics of asset returns have been widely studied in financial econometrics. A key component of the model, spot volatility, plays a crucial role in option pricing, portfolio management, and financial risk assessment. In this dissertation, we consider three problems related to the estimation of spot volatility using high-frequency asset returns. We first revisit the problem of estimating the spot volatility of an It\^o semimartingale using a kernel estimator. We prove a Central Limit Theorem with an optimal convergence rate for a general two-sided kernel under quite mild assumptions, which includes leverage effects and jumps of …

Truncated Realized Variations Of Lévy Models: Optimality, Debiasing, And Implementation Approaches, Yuchen Han

Arts & Sciences Electronic Theses and Dissertations

Statistical inference for stochastic processes under high-frequency observations has been an active research area in econometrics and financial statistics for over twenty years. In this thesis, we consider some aspects related to the estimation of the volatility of an Itô semimartingale in the presence of Lévy-type jumps, which is of fundamental importance in derivatives pricing evaluation, risk management and portfolio allocation. The main technique we use is the Truncated Realized Variation (TRV) that is both rate- and variance-efficient, in the Cramer-Rao lower bound sense, when jumps are of bounded variation.

Motivated by recent results that state that the optimal threshold …

Development Of Redox-Responsive Phenazine-Based Foldamers. Acylative Kinetic Resolution Of Hydroxamic Acids, Jingwei Yin

Arts & Sciences Electronic Theses and Dissertations

Two different research directions have been presented in this thesis. The first project is about phenazine-based foldamers as molecular actuators. Researchers have been interested in the design and synthesis of foldamers and molecular actuators for years. We began our exploration by demonstrating that phenazine-1,6-dicarboxamides can function as redox-responsive molecular switches. We then designed and synthesized two generations of phenazine-based interleafed foldamers and studied their stability and redox behaviors under chemical and electrochemical conditions. In the second project, we have developed the first acylative kinetic resolution on hydroxamic acids. Although chiral hydroxamic acids have extensive applications, synthetic methods towards them are …

Functionalized Plasmonic Nanostructures For Ultrasensitive Single Cell Analysis, Priya Rathi

Arts & Sciences Electronic Theses and Dissertations

Ultrasensitive detection and quantification of soluble, secreted and cell surface-bound proteins is critical for advancing our understanding of cellular systems, enabling effective drug development, novel therapies, and bio-diagnostics. However, exiting technologies are largely limited by their sensitivity, making the detection and quantification of low-abundant proteins extremely challenging. This forms a major barrier in various fields of biology and biomedical sciences. In this work, we introduce novel cellular analysis methodologies based on plasmon-enhanced fluorescence for analyzing cell structure and probing surface and secreted proteins from cells. In the first part, we introduce plasmon-enhanced expansion microscopy and demonstrate the effectiveness of employing …

Toward Enhancing The Synthesis Of Renewable Polymers: Feedstock Conversions And Functionalizable Copolymers, Tedd Casey Wiessner

Arts & Sciences Electronic Theses and Dissertations

This thesis describes research under the rubric of the Center for Sustainable Polymers that is aimed at two separate goals. The goal of the first project (Chapters 1 and 2) was to develop a deeper mechanistic understanding of a method for the synthesis of linear α-olefins, while the second aimed at synthesizing statistical copolymers that incorporate olefin-containing monomers through ring-opening transesterification polymerization and showing that these copolymers could be functionalized. In Chapter 1, published methods for the conversion of fatty acids to linear α-olefins are reviewed to provide context for the mechanistic work we accomplished (Chapter 2). In Chapter 2 …

Observation Of Novel Phases Of Quantum Matter Beyond Topological Insulator, Sabin Regmi

Electronic Theses and Dissertations, 2020-2023

Because of the unique electronic properties, intriguing novel phenomena, and potentiality in quantum device applications, the quantum materials with non-trivial band structures have enticed a bulk of research works over the last two decades. The experimental discovery of the three-dimensional topological insulators (TIs) - bulk insulators with surface conduction via spin-polarized electrons - kicked off the flurry of research interests towards such materials, which resulted in the experimental discovery of new topological phases of matter beyond TIs. The topological semimetallic phase in Dirac, Weyl, and nodal-line semimetals is an example, where the classification depends on the dimensionality, degeneracy, and symmetry …

Effect Of X-Ray Illumination On Magnetic Domain Memory In [Co/Pd]/Irmn Multilayers, Colby Singint Walker

Theses and Dissertations

This thesis focuses on investigating the possible x-ray illumination effects on the magnetic domain memory (MDM) in magnetic [Co/Pd]IrMn multilayers. In this material, MDM is induced via exchange couplings between the ferromagnetic Co/Pd layer and the antiferromagnetic IrMn layer. To carry out this investigation, we have used magneto-transport and x-ray resonant magnetic scattering. The use of magneto-transport in-situ at synchrotron x-ray scattering facility has allowed us to follow the gradual effect of x-ray illumination on the amount of exchange bias, initially present after field cooling the material. With our in-situ measurements we have been able to see that x-ray illumination …

Development Of Novel Nucleophile-Intercepted Beckmann Fragmentations And Progress Toward The Total Synthesis Of 2(S)-Cathafoline, Evan M. Dunkley

Dartmouth College Master’s Theses

This thesis is comprised of two chapters, the first being the discovery of a novel nucleophile-intercepted Beckmann fragmentation of [2.2.1] indoline systems that resulted in highly stereo- and regioselective reactions. Chapter one details the exploration of this reaction as well as its relevant background information detailing its significance. Chapter two describes the application of the novel nucleophile-intercepted Beckmann fragmentation in the context of a total synthesis of akuammilline alkaloid 2(S)-cathafoline. While the target natural product was never synthesized, unpredicted reactivity resulted in interesting discoveries worthy of discussion.

Preferential Stiffness And The Crack-Tip Fields Of An Elastic Porous Solid Based On The Density-Dependent Moduli Model, Hyun C. Yoon, S. M. Mallikarjunaiah, Dambaru Bhatta

School of Mathematical and Statistical Sciences Faculty Publications and Presentations

In this paper, we study the preferential stiffness and the crack-tip fields for an elastic porous solid of which material properties are dependent upon the density. Such a description is necessary to describe the failure that can be caused by damaged pores in many porous bodies such as ceramics, concrete and human bones. To that end, we revisit a new class of implicit constitutive relations under the assumption of small deformation. Although the constitutive relationship \textit{appears linear} in both the Cauchy stress and linearized strain, the governing equation bestowed from the balance of linear momentum results in a quasi-linear partial …

The Origin And Evolution Of Impact Crater Lakes: A Case Study Of The Ries Impact Structure, Germany, Matthew J. O. Svensson

Electronic Thesis and Dissertation Repository

Impact events are known to generate hydrothermal systems, which can subsequently vent into an overlying crater lake and potentially create ideal conditions for some microbial life-forms. Thus, early post-impact sedimentary deposits would be excellent targets for Mars sample return, and as such, the robust characterization of such deposits on Earth is critical. In this thesis, we establish an improved understanding of how the Ries crater lake formed, and how an active impact-generated hydrothermal system influenced its early evolution. The ~14.8 Ma Ries impact structure hosts the majority of its paleolake deposits within the structure's central basin with some deposits situated …

Uv-Light-Tunable P-/N-Type Chemiresistive Gas Sensors Based On Quasi-1d Tis3 Nanoribbons: Detection Of Isopropanol At Ppm Concentrations, Victor V. Sysoev, Andrey V. Lashkov, Alexey Lipatov, Ilya A. Plugin, Michael Bruns, Dirk Fuchs, Alexey S. Varezhnikov, Mustahsin Adib, Martin Sommer, Alexander Sinitskii

Chemistry Department: Faculty Publications

The growing demand of society for gas sensors for energy-efficient environmental sensing stimulates studies of new electronic materials. Here, we investigated quasi-one-dimensional titanium trisulfide (TiS₃) crystals for possible applications in chemiresistors and on-chip multisensor arrays. TiS₃ nanoribbons were placed as a mat over a multielectrode chip to form an array of chemiresistive gas sensors. These sensors were exposed to isopropanol as a model analyte, which was mixed with air at low concentrations of 1–100 ppm that are below the Occupational Safety and Health Administration (OSHA) permissible exposure limit. The tests were performed at room temperature (RT), as …

Formation And Tectonic Evolution Of Structural Slices In Eastern Kargı Massif (Çorum, Türkiye), Cihan Yalçin, Nurullah Hani̇lçi̇, Mustafa Kumral, Mustafa Kaya

Bulletin of the Mineral Research and Exploration

The closure of Tethys Ocean has led to shaping the Central Pontides together with different types of rocks. In the east of Kargı (Gökçedoğan), which is located in the Central Pontides, allochthonous rocks of Late Palaeozoic-Early Cenozoic age and autochthonous units exist together, and allochthonous rocks present various tectono-stratigraphical sequences. Distinctive tectonic slices developed in the area as a consequence of the thrusting of the Permian carbonates from the north towards the south over the Middle Jurassic accretionary Complex (Kunduz Metamorphites) that form the basement of the area, and also because of the thrusting of the units of the Kirazbaşı …

Future Colorado River Basin Drought And Surplus, Rama Bedri, Thomas Piechota

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Historical and future drought and surplus periods in the Colorado River basin are evaluated based on eight climate scenarios. Unimpaired streamflow from 17 stations in the Colorado River are evaluated based on U.S. Geological Survey, Bureau of Reclamation, and Coupled Modeled Intercomparison Projection 5 downscaled data from 1950–2099. Representative Concentration Pathway (RCP) 4.5 and 8.5 emission scenarios are considered for four climate models (HadGEM2-ES, CNRM-CM5, CanESM2, MI-ROC5). Drought (surplus) quantities, magnitudes, severities, and water year flows are compared for the historical and future periods. Results indicate that there is a significant difference between the historical record and future projections. The …

Cloud Container Security’ Next Move, Vishakha Sadhwani

Dissertations and Theses

In the last few years, it is apparent to cybersecurity experts everywhere that the proverbial container tech genie is out of the bottle, and has been widely embraced across multiple organizations. To achieve the flexibility of building and deploying applications anywhere and everywhere, cloud native environments have gained great momentum and made the development lifecycle simpler than ever. However, container environments brings with them a range of cybersecurity issues that includes images, containers, hosts, runtimes, registries, and orchestration platforms, which needs the necessity to focus on investing in securing your container stack.

According to this report[1], released by cloud-native …

Uniqueness Of Steady State Positive Solutions To A General Elliptic System With Dirichlet Boundary Conditions, Joon Hyuk Kang

Faculty Publications

The purpose of this paper is to give conditions for the uniqueness of positive solution to a rather general type of elliptic system of the Dirichlet problem on a bounded domain Ω in Rⁿ. Also considered are the effects of perturbations on the coexistence state and uniqueness.