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Articles 12061 - 12090 of 302419

Full-Text Articles in Physical Sciences and Mathematics

Density Dependence And Dynamics Of Dipole-Dipole Interactions Among Rydberg Atoms, Hannah Conley Jul 2023

Density Dependence And Dynamics Of Dipole-Dipole Interactions Among Rydberg Atoms, Hannah Conley

Physics and Astronomy Summer Fellows

After trapping atoms, exciting them to an initial high-energy Rydberg state, and allowing them a brief time to exchange energy with each other through dipole-dipole interactions, we observe how their energies are redistributed among various energy levels. The measurements we make in this physical experiment do not give insight into how individual atoms interact or metrics like fidelity and entanglement entropy, which impact our results. For this reason, it is useful to compare our results from the physical experiment to those of our simulation on a supercomputer, in which we can track the final and initial energy of individual atoms …


Carbon Nanotubes Animated, Nicholas Onyemeke Jul 2023

Carbon Nanotubes Animated, Nicholas Onyemeke

Chemistry Summer Fellows

In this project, I implemented the knowledge about carbon nanotubes into an animated short. The animated short is meant to simplify the research so that anyone can understand regardless of their background in science. The research I did was on how nanotubes can be used in the medical field as a measure to inhibit bacteria growth. A nanotube dye solution was synthesized to inoculate bacteria along with an antibiotic solution with the nanotubes. This was done to observe how well the nanotubes can inhibit bacteria growth without the need for a drug compared to the effectiveness when it has a …


Sentiment Analysis Before And During The Covid-19 Pandemic, Emily Musgrove Jul 2023

Sentiment Analysis Before And During The Covid-19 Pandemic, Emily Musgrove

Mathematics Summer Fellows

This study examines the change in connotative language use before and during the Covid-19 pandemic. By analyzing news articles from several major US newspapers, we found that there is a statistically significant correlation between the sentiment of the text and the publication period. Specifically, we document a large, systematic, and statistically significant decline in the overall sentiment of articles published in major news outlets. While our results do not directly gauge the sentiment of the population, our findings have important implications regarding the social responsibility of journalists and media outlets especially in times of crisis.


Ortho-Fluoro Effect On The C–C Bond Activation Of Benzonitrile Using Zerovalent Nickel, Sébastien Lachaize, Dominique C. Gallegos, Juliana J. Antonio, Abdurrahman C. Atesin, Tülay A. Ateşin, William D. Jones Jul 2023

Ortho-Fluoro Effect On The C–C Bond Activation Of Benzonitrile Using Zerovalent Nickel, Sébastien Lachaize, Dominique C. Gallegos, Juliana J. Antonio, Abdurrahman C. Atesin, Tülay A. Ateşin, William D. Jones

Chemistry Faculty Publications and Presentations

The effect of fluoro substitution on the C–C bond activation of aromatic nitriles has been studied by reacting a variety of fluorinated benzonitriles with the nickel(0) fragment [Ni(dippe)] and by locating the reaction intermediates and transition-state structures on the potential energy surface by using density functional theory calculations with the [Ni(dmpe)] fragment (dippe = 1,2-bis(diisopropylphosphino)ethane, dmpe = 1,2-bis(dimethylphosphino)ethane). As in the previous reports, the reaction of fluorinated benzonitriles with the [Ni(dippe)] fragment initially formed an η2-nitrile complex, which then converted to the C–CN bond activation product. Thermodynamic parameters for the equilibrium between these complexes have been determined experimentally in both …


On Training Neurons With Bounded Compilations, Lance Kennedy Jul 2023

On Training Neurons With Bounded Compilations, Lance Kennedy

Master of Science in Computer Science Theses

Knowledge compilation offers a formal approach to explaining and verifying the behavior of machine learning systems, such as neural networks. Unfortunately, compiling even an individual neuron into a tractable representation such as an Ordered Binary Decision Diagram (OBDD), is an NP-hard problem. In this thesis, we consider the problem of training a neuron from data, subject to the constraint that it has a compact representation as an OBDD. Our approach is based on the observation that a neuron can be compiled into an OBDD in polytime if (1) the neuron has integer weights, and (2) its aggregate weight is bounded. …


Interposition Based Container Optimization For Data Intensive Applications, Rohan Tikmany Jul 2023

Interposition Based Container Optimization For Data Intensive Applications, Rohan Tikmany

College of Computing and Digital Media Dissertations

Reproducibility of applications is paramount in several scenarios such as collaborative work and software testing. Containers provide an easy way of addressing reproducibility by packaging the application's software and data dependencies into one executable unit, which can be executed multiple times in different environments. With the increased use of containers in industry as well as academia, current research has examined the provisioning and storage cost of containers and has shown that container deployments often include unnecessary software packages. Current methods to optimize the container size prune unnecessary data at the granularity of files and thus make binary decisions. We show …


Fixed Point Results In Soft Fuzzy Metric Spaces, Sonam Sonam, Ramakant Bhardwaj, Satyendra Narayan Jul 2023

Fixed Point Results In Soft Fuzzy Metric Spaces, Sonam Sonam, Ramakant Bhardwaj, Satyendra Narayan

Publications and Scholarship

The primary objective of the paper is to present the Banach contraction theorem in soft fuzzy metric spaces while taking into consideration a restriction on the soft fuzzy metric between the soft points of the absolute soft set. A new altering distance function, namely the Ψ -contraction function, is introduced on soft fuzzy metric spaces, and some fixed point results are proven by considering soft mappings that comprise Ψ -contraction with the continuity of soft t-norm. In addition to that, some illustrations are supplied for the support of the established soft fuzzy Banach contraction theorem and fixed point results over …


Bifurcation From Infinity With Oscillatory Nonlinearity For Neumann Problems, M. Chhetri, Nsoki Mavinga, R. Pardo Jul 2023

Bifurcation From Infinity With Oscillatory Nonlinearity For Neumann Problems, M. Chhetri, Nsoki Mavinga, R. Pardo

Mathematics & Statistics Faculty Works

We consider a sublinear perturbation of an elliptic eigenvalue problem with Neumann boundary condition. We give sufficient conditions on the nonlinear perturbation which guarantee that the unbounded continuum, bifurcating from infinity at the first eigenvalue, contains an unbounded sequence of turning points as well as an unbounded sequence of resonant solutions. We prove our result by using bifurcation theory combined with a careful analysis of the oscillatory behavior of the continuum near the bifurcation point.


Two-Particle Azimuthal Correlations In Γp Interactions Using Ppb Collisions At √SNn=8.16tev, A. Tumasyan Jul 2023

Two-Particle Azimuthal Correlations In Γp Interactions Using Ppb Collisions At √SNn=8.16tev, A. Tumasyan

Department of Physics and Astronomy: Faculty Publications

The first measurements of the Fourier coefficients (V) of the azimuthal distributions of charged hadrons emitted from photon-proton (γp) interactions are presented. The data are extracted from 68.8nb−1of ultra-peripheral proton-lead (pPb) collisions at √sNN=8.16 TeVusing the CMS detector. The high energy lead ions produce a flux of photons that can interact with the oncoming proton. This γp system provides a set of unique initial conditions with multiplicity lower than in photon-lead collisions but comparable to recent electron-positron and electron-proton data. The V coefficients are presented in ranges of event multiplicity and transverse momentum …


2023 July 20 - Tennessee Weekly Drought Summary, Tennessee Climate Office, East Tennessee State University Jul 2023

2023 July 20 - Tennessee Weekly Drought Summary, Tennessee Climate Office, East Tennessee State University

Tennessee Climate Office Weekly Drought Summaries

No abstract provided.


China’S Governance: Strategy Choice And Future Vision For Combating Desertification, Guipeng Cui, Chunlei Xiao, Jiaqiang Lei, Xiaosong Li, Yingshuang Bao, Qi Lu Jul 2023

China’S Governance: Strategy Choice And Future Vision For Combating Desertification, Guipeng Cui, Chunlei Xiao, Jiaqiang Lei, Xiaosong Li, Yingshuang Bao, Qi Lu

Bulletin of Chinese Academy of Sciences (Chinese Version)

China has made remarkable achievements in combating desertification over the past 70 years. At present, China has entered a new stage of combating desertification while facing many problems such as large desertification land base and high difficulty in combating desertification, and it is more important to meet the national strategic needs of ecological construction, rural revitalization, and the development and utilization of renewable energy in desert, Gobi, and wasteland areas. The strategic choice of combating desertification in China in the new era is overall improvement and key breakthroughs. The core of the strategy is whole-area governance, innovation-driven, and technology integration. …


Hydrology Data For Fern Cave, Alabama (2020-2022), Benjamin Tobin, Benjamin V. Miller, Matthew Niemiller, Andrea Erhardt Jul 2023

Hydrology Data For Fern Cave, Alabama (2020-2022), Benjamin Tobin, Benjamin V. Miller, Matthew Niemiller, Andrea Erhardt

Research Data--KGS

Dataset includes water level from four sites within Fern Cave in Jackson County Alabama. Additionally, it includes chemistry of water, sediments and cave-adapted isopods.


Survey Of Personalized Learning Software Systems: A Taxonomy Of Environments, Learning Content, And User Models, Heba Ismail, Nada Hussein, Saad Harous, Ashraf Khalil Jul 2023

Survey Of Personalized Learning Software Systems: A Taxonomy Of Environments, Learning Content, And User Models, Heba Ismail, Nada Hussein, Saad Harous, Ashraf Khalil

All Works

This paper presents a comprehensive systematic review of personalized learning software systems. All the systems under review are designed to aid educational stakeholders by personalizing one or more facets of the learning process. This is achieved by exploring and analyzing the common architectural attributes among personalized learning software systems. A literature-driven taxonomy is recognized and built to categorize and analyze the reviewed literature. Relevant papers are filtered to produce a final set of full systems to be reviewed and analyzed. In this meta-review, a set of 72 selected personalized learning software systems have been reviewed and categorized based on the …


A Hybrid Metaheuristic And Computer Vision Approach To Closed-Loop Calibration Of Fused Deposition Modeling 3d Printers, Graig S. Ganitano, Shay V. Wallace, Benji Maruyama, Gilbert L. Peterson Jul 2023

A Hybrid Metaheuristic And Computer Vision Approach To Closed-Loop Calibration Of Fused Deposition Modeling 3d Printers, Graig S. Ganitano, Shay V. Wallace, Benji Maruyama, Gilbert L. Peterson

Faculty Publications

Fused deposition modeling (FDM) is one of the most popular additive manufacturing (AM) technologies for reasons including its low cost and versatility. However, like many AM technologies, the FDM process is sensitive to changes in the feedstock material. Utilizing a new feedstock requires a time-consuming trial-and-error process to identify optimal settings for a large number of process parameters. The experience required to efficiently calibrate a printer to a new feedstock acts as a barrier to entry. To enable greater accessibility to non-expert users, this paper presents the first system for autonomous calibration of low-cost FDM 3D printers that demonstrates optimizing …


Implementation Path And Strategic Planning Of Winning The Battle Of “Three-North” And Reconstructing “New Three-North”, Qi Lu, Chunlei Xiao, Yingshuang Bao, Mengchun Cui, Xiaoming Cao, Xiao Que, Liu Yang, Guipeng Cui Jul 2023

Implementation Path And Strategic Planning Of Winning The Battle Of “Three-North” And Reconstructing “New Three-North”, Qi Lu, Chunlei Xiao, Yingshuang Bao, Mengchun Cui, Xiaoming Cao, Xiao Que, Liu Yang, Guipeng Cui

Bulletin of Chinese Academy of Sciences (Chinese Version)

Over the past 45 years, China has accomplished great achievements in carrying out “Three-North” project. Through largescale vegetation construction, the trends of land desertification, soil salinization, soil erosion and the deterioration of people’s living environment in the “Three-North” areas have been effectively restrained. The people in the desert area are getting rid of poverty and living a healthy life. In the new era, the “Three-North” project has encountered new demands, new challenges and new opportunities, and it is urgent to achieve a significant transform and upgrade and to improve quality and efficiency. This paper summarizes the current situation of the …


The Battle On The Edge Of Hexi Corridor–Taklimakan Desert: Wind-Blown Sand Situation And Prevention Tasks Of Desertification Control, Jiaqiang Lei, Xin Gao, Yongcheng Zhao, Heqiang Du, Qing He, Hongjing Ren, Xiaoyu Meng, Zihao Hu, Zuowei Yang Jul 2023

The Battle On The Edge Of Hexi Corridor–Taklimakan Desert: Wind-Blown Sand Situation And Prevention Tasks Of Desertification Control, Jiaqiang Lei, Xin Gao, Yongcheng Zhao, Heqiang Du, Qing He, Hongjing Ren, Xiaoyu Meng, Zihao Hu, Zuowei Yang

Bulletin of Chinese Academy of Sciences (Chinese Version)

In order to implement the spirit of General Secretary Xi Jinping’s important speech on strengthening the comprehensive control of desertification and promoting key ecological engineering projects such as the “Three-North Shelterbelt Program”, this study is designated to make concrete efforts to win the battle against desertification on the edge of Hexi Corridor—Taklimakan Desert. The study deeply explores the situation of wind-blown sand flux and prevention tasks in the area. Based on the characteristics of desertified land and wind-blown sand activities on the edge of Hexi Corridor—Taklimakan Desert, the goal is set to effectively prevent the spread of sand and control …


Exerting The Think Tank Role Of Academic Divisions And Serving The Needs Of National Dual Carbon Strategy—Major Consultancy Project Of Carbon Neutrality By Cas Academic Divisions, Jianming Gong, Hejun Yu, Xiaonan Duan, Jiansheng Qu, Jingjing Zeng, Chen Zhang Jul 2023

Exerting The Think Tank Role Of Academic Divisions And Serving The Needs Of National Dual Carbon Strategy—Major Consultancy Project Of Carbon Neutrality By Cas Academic Divisions, Jianming Gong, Hejun Yu, Xiaonan Duan, Jiansheng Qu, Jingjing Zeng, Chen Zhang

Bulletin of Chinese Academy of Sciences (Chinese Version)

The main responsibility of the national strategic scientific and technological force is to focus on national strategic needs, refine key scientific problems in basic research, and gather resources to conduct original and leading scientific and technological research. The dual carbon goal is an internal requirement to implement the new development concept, construct a new development pattern, and promote high-quality development. It is a major strategic decision made by the Central Committee of the Communist Party of China in current domestic and international situations. We take the carbon neutrality major consulting project, Chinese Academy of Sciences (CAS), as a specific case, …


International Soft Law Governance Of Artificial Intelligence Ethics: Current Situation, Challenges And Countermeasures, Mingting Zhu, Chongli Xu Jul 2023

International Soft Law Governance Of Artificial Intelligence Ethics: Current Situation, Challenges And Countermeasures, Mingting Zhu, Chongli Xu

Bulletin of Chinese Academy of Sciences (Chinese Version)

Artificial intelligence (AI) technology not only rapidly empowers economic and social development, but may also trigger many ethical issues highly related to the characteristics and development of AI technology itself. The rise of international soft law in the field of AI ethical governance is almost inevitable due to its flexibility, efficiency, low application cost, ability to fill the gap in hard law, and convenience in distinguishing governance and layered response to ethical issues. Under the current situation of developed international soft law and outdated hard law in this field, faced with the governance challenge of unstable cooperation among subjects of …


Integrated Observation And Research On Climate And Environment From Boundary Layer To Middle And Upper Levels Of Atmosphere, Xiang’Ao Xia, Yufang Tian, Yunfei Wu, Jing Yang, Dongsheng Ji, Jinqiang Zhang, Renjian Zhang, Pucai Wang, Hongbin Chen, Xiushu Qie, Daren Lü Jul 2023

Integrated Observation And Research On Climate And Environment From Boundary Layer To Middle And Upper Levels Of Atmosphere, Xiang’Ao Xia, Yufang Tian, Yunfei Wu, Jing Yang, Dongsheng Ji, Jinqiang Zhang, Renjian Zhang, Pucai Wang, Hongbin Chen, Xiushu Qie, Daren Lü

Bulletin of Chinese Academy of Sciences (Chinese Version)

After more than 50 years of development, the Xianghe station (XH), Institute of Atmospheric Physics, Chinese Academy of Sciences, has been equipped with comprehensive detection capabilities covering from the boundary layer to the middle and upper levels of the atmosphere. As one of the few atmospheric integrated field scientific test stations in the world, XH has joined a number of important networks. Many large international field campaigns have been carried out. Long-term continuous observation data are widely used to study exchange of energy and mass in the middle and upper atmosphere, atmospheric physical chemistry and air quality in the boundary …


Xianghe Integrated Observatory Of Climate And Environment, Institute Of Atmospheric Physics, Chinese Academy Of Sciences Jul 2023

Xianghe Integrated Observatory Of Climate And Environment, Institute Of Atmospheric Physics, Chinese Academy Of Sciences

Bulletin of Chinese Academy of Sciences (Chinese Version)

No abstract provided.


Measuring And Enhancing The Ionic Conductivity Of Chloroaluminate Electrolytes For Al-Ion Batteries, Anthony J Lucio, Iwan Sumarlan, Elena Bulmer, Igor Efimov, Stephen Viles, A Robert Hillman, Christopher J Zaleski, Karl S Ryder Jul 2023

Measuring And Enhancing The Ionic Conductivity Of Chloroaluminate Electrolytes For Al-Ion Batteries, Anthony J Lucio, Iwan Sumarlan, Elena Bulmer, Igor Efimov, Stephen Viles, A Robert Hillman, Christopher J Zaleski, Karl S Ryder

Student and Faculty Publications

At the core of the aluminum (Al) ion battery is the liquid electrolyte, which governs the underlying chemistry. Optimizing the rheological properties of the electrolyte is critical to advance the state of the art. In the present work, the chloroaluminate electrolyte is made by reacting AlCl3 with a recently reported acetamidinium chloride (Acet-Cl) salt in an effort to make a more performant liquid electrolyte. Using AlCl3:Acet-Cl as a model electrolyte, we build on our previous work, which established a new method for extracting the ionic conductivity from fitting voltammetric data, and in this contribution, we validate the method across a …


Advances In Copula Estimation And Distribution Theory, Yishan Zang Jul 2023

Advances In Copula Estimation And Distribution Theory, Yishan Zang

Electronic Thesis and Dissertation Repository

This dissertation initially features distributional results related to copulas. Four distinct copula density estimation methodologies, including Bernstein’s polynomial approximation, are proposed and criteria for the selection of their tuning parameters are provided. These four approaches were found to produce similar density estimates, which validates their suitability. Moreover, the copula associated with a Wiener process and its running maximum is determined, and an illustrative numerical example is presented. The principal properties of Spearman’s, Kendall’s, Blomqvist’ and Hoeffding’s measures of association as well as their representations in terms of copulas are also discussed. Then, a novel method that is based on an …


Learning That Matters Is Messy: Experiments Revealing Hidden Potential In Higher Education, Ryan Derby-Talbot Jul 2023

Learning That Matters Is Messy: Experiments Revealing Hidden Potential In Higher Education, Ryan Derby-Talbot

Turning Toward Being: The Journal of Ontological Inquiry in Education

Why are some learning experiences so profound that they alter our worlds, whereas others don’t end up sticking at all? The author investigates this question in the context of undergraduate education, recounting several educational experiments that highlight subtle but powerful aspects of the student learning experience. By exploring a different approach to teaching a math course, an alternative framework for academic specialization instead of traditional majors, and a radical approach to designing new institutions, an encounter with the hidden, ontological dimension of learning becomes possible. Accessing the ontological experience of the learner opens up new possibilities for meaningful, deep, and …


A Molten Salt Test Loop For Component And Instrumentation Testing, T L. Head, Allison M. Berry, Keaton J. Brewster, Robert L. Brown, Hailey N. Burden, Reuben Byrd, Timothy Doty, Jess Dowdy, Kameron A. Hill, R. A. Jinkerson, Timothy J. Kennedy, Ronald C. Laehn, Dakotah Martinez, Samuel L. Mulder, Charles Onstead, Kim L. Pamplin, Dylan C. Pfeifer, Michael B. Ranger, Aaron D. Robison, Nathaniel T. Rowlands, Raymond E. Smith, Matthew T. Steele, R. S. Towell, Travis Towell, Olive Tuyishimire, T. S. Watson Jul 2023

A Molten Salt Test Loop For Component And Instrumentation Testing, T L. Head, Allison M. Berry, Keaton J. Brewster, Robert L. Brown, Hailey N. Burden, Reuben Byrd, Timothy Doty, Jess Dowdy, Kameron A. Hill, R. A. Jinkerson, Timothy J. Kennedy, Ronald C. Laehn, Dakotah Martinez, Samuel L. Mulder, Charles Onstead, Kim L. Pamplin, Dylan C. Pfeifer, Michael B. Ranger, Aaron D. Robison, Nathaniel T. Rowlands, Raymond E. Smith, Matthew T. Steele, R. S. Towell, Travis Towell, Olive Tuyishimire, T. S. Watson

Chemistry and Biochemistry

Molten salt is an effective coolant for a wide range of applications, including nuclear reactors, concentrated solar power, and other high temperature industrial heat transfer processes. The technical readiness level of components and instrumentation for high-temperature molten salt applications needs improvement for molten salt to be more widely adopted. A molten salt test loop was designed, built, and commissioned as a test bed to address these issues. The molten salt test loop at Abilene Christian University was built out of 316 stainless steel with a forced flow centrifugal-type pump, and was instrumented for remote operation. A low-temperature molten nitrate salt …


Computation Of The Basic Reproduction Numbers For Reaction-Diffusion Epidemic Models, Chayu Yang, Jin Wang Jul 2023

Computation Of The Basic Reproduction Numbers For Reaction-Diffusion Epidemic Models, Chayu Yang, Jin Wang

Department of Mathematics: Faculty Publications

We consider a class of k-dimensional reaction-diusion epidemic models (k = 1; 2; • • • ) that are developed from autonomous ODE systems. We present a computational approach for the calculation and analysis of their basic reproduction numbers. Particularly, we apply matrix theory to study the relationship between the basic reproduction numbers of the PDE models and those of their underlying ODE models. We show that the basic reproduction numbers are the same for these PDE models and their associated ODE models in several important scenarios. We additionally provide two numerical examples to verify our analytical results.


Interpretable Timbre Synthesis Using Variational Autoencoders Regularized On Timbre Descriptors, Anastasia Natsiou, Luca Longo, Sean O'Leary Jul 2023

Interpretable Timbre Synthesis Using Variational Autoencoders Regularized On Timbre Descriptors, Anastasia Natsiou, Luca Longo, Sean O'Leary

Conference papers

Controllable timbre synthesis has been a subject of research for several decades, and deep neural networks have been the most successful in this area. Deep generative models such as Variational Autoencoders (VAEs) have the ability to generate a high-level representation of audio while providing a structured latent space. Despite their advantages, the interpretability of these latent spaces in terms of human perception is often limited. To address this limitation and enhance the control over timbre generation, we propose a regularized VAE-based latent space that incorporates timbre descriptors. Moreover, we suggest a more concise representation of sound by utilizing its harmonic …


Generative Relevance Feedback With Large Language Models, Iain Mackie, Shubham Chatterjee, Jeffrey Dalton Jul 2023

Generative Relevance Feedback With Large Language Models, Iain Mackie, Shubham Chatterjee, Jeffrey Dalton

Computer Science Faculty Research & Creative Works

Current query expansion models use pseudo-relevance feedback to improve first-pass retrieval effectiveness; however, this fails when the initial results are not relevant. Instead of building a language model from retrieved results, we propose Generative Relevance Feedback (GRF) that builds probabilistic feedback models from long-form text generated from Large Language Models. We study the effective methods for generating text by varying the zero-shot generation subtasks: queries, entities, facts, news articles, documents, and essays. We evaluate GRF on document retrieval benchmarks covering a diverse set of queries and document collections, and the results show that GRF methods significantly outperform previous PRF methods. …


Neuro-Symbolic Representations For Information Retrieval, Laura Dietz, Hannah Bast, Shubham Chatterjee, Jeff Dalton, Jian Yun Nie, Rodrigo Nogueira Jul 2023

Neuro-Symbolic Representations For Information Retrieval, Laura Dietz, Hannah Bast, Shubham Chatterjee, Jeff Dalton, Jian Yun Nie, Rodrigo Nogueira

Computer Science Faculty Research & Creative Works

This tutorial will provide an overview of recent advances on neuro-symbolic approaches for information retrieval. A decade ago, knowledge graphs and semantic annotations technology led to active research on how to best leverage symbolic knowledge. At the same time, neural methods have demonstrated to be versatile and highly effective. From a neural network perspective, the same representation approach can service document ranking or knowledge graph reasoning. End-to-end training allows to optimize complex methods for downstream tasks. We are at the point where both the symbolic and the neural research advances are coalescing into neuro-symbolic approaches. The underlying research questions are …


Topological Data Analysis Of Convolutional Neural Networks Using Depthwise Separable Convolutions, Eliot Courtois Jul 2023

Topological Data Analysis Of Convolutional Neural Networks Using Depthwise Separable Convolutions, Eliot Courtois

Dissertations

In this dissertation, we present our contribution to a growing body of work combining the fields of Topological Data Analysis (TDA) and machine learning. The object of our analysis is the Convolutional Neural Network, or CNN, a predictive model with a large number of parameters organized using a grid-like geometry. This geometry is engineered to resemble patches of pixels in an image, and thus CNNs are a conventional choice for an image-classifying model.

CNNs belong to a larger class of neural network models, which, starting at a random initialization state, undergo a gradual fitting (or training) process, often a …


Connecting The Optical Regime To The X-Ray In Neutron Star Low Mass X-Ray Binaries, Alexander B. Igl Jul 2023

Connecting The Optical Regime To The X-Ray In Neutron Star Low Mass X-Ray Binaries, Alexander B. Igl

LSU Doctoral Dissertations

Using Rossi X-Ray Timing Explorer and Otto Struve Telescope data of low mass X-ray binaries (LMXBs) Cyg X-2 and Sco X-1, the optical regime’s relationship to the X-ray was investigated through several angles. Discrete cross correlations using the optical and X-ray data revealed evidence of reprocessing in both datasets. These were more consistently present in Sco X-1, where both small and obvious features were seen at less than 4 s of optical lag. The size of these lags makes it likely that most of the reprocessing is taking place on the accretion disk. Parameterization of the Z tracks led to …