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Articles 61 - 90 of 1095
Full-Text Articles in Physical Sciences and Mathematics
Learning Internal State Memory Representations From Observation, Josiah Wong
Learning Internal State Memory Representations From Observation, Josiah Wong
Electronic Theses and Dissertations
Learning from Observation (LfO) is a machine learning paradigm that mimics how people learn in daily life: learning how to do something simply by watching someone else do it. LfO has been used in various applications, from video game agent creation to driving a car, but it has always been limited by the inability of an observer to know what a performing entity chooses to remember as they act in an environment. Various methods have either ignored the effects of memory or otherwise made simplistic assumptions about its structure. In this dissertation, we propose a new method, Memory Composition Learning, …
Mathematical Investigation Of The Spatial Spread Of An Infectious Disease In A Heterogeneous Environment, Arielle Gaudiello
Mathematical Investigation Of The Spatial Spread Of An Infectious Disease In A Heterogeneous Environment, Arielle Gaudiello
Electronic Theses and Dissertations
Outbreaks of infectious diseases can devastate a population. Researchers thus study the spread of an infection in a habitat to learn methods of control. In mathematical epidemiology, disease transmission is often assumed to adhere to the law of mass action, yet there are numerous other incidence terms existing in the literature. With recent global outbreaks and epidemics, spatial heterogeneity has been at the forefront of these epidemiological models. We formulate and analyze a model for humans in a homogeneous population with a nonlinear incidence function and demographics of birth and death. We allow for the combination of host immunity after …
Metastable-State Photoacids: Synthesis, Properties, And Applications, Parth Patel
Metastable-State Photoacids: Synthesis, Properties, And Applications, Parth Patel
Electronic Theses and Dissertations
Reversible photochromic compounds have the ability to reversibly change its color when it absorbs photons of a particular wavelength. This process of color change is a consequence of structural changes within the compound, such as cis-trans photo-isomerization. Some examples of photochromic compounds are spiropyrans, spirooxazines, diarylethenes and azobenzenes. These compounds have been extensively studied for decades, and are used in various applications such as biomedicine, chemical sensors and harvesting solar energy. However, majority of photochromic compounds are initially activated by ultraviolet (UV) light. The use of UV light is harmful for biological applications and photo-degrade the compound over repeated use. …
A Study Of Perceptions On Incident Response Exercises, Information Sharing, Situational Awareness, And Incident Response Planning In Power Grid Utilities, Joseph Garmon
Electronic Theses and Dissertations
The power grid is facing increasing risks from a cybersecurity attack. Attacks that shut off electricity in Ukraine have already occurred, and successful compromises of the power grid that did not shut off electricity to customers have been privately disclosed in North America. The objective of this study is to identify how perceptions of various factors emphasized in the electric sector affect incident response planning. Methods used include a survey of 229 power grid personnel and the use of partial least squares structural equation modeling to identify causal relationships. This study reveals the relationships between perceptions by personnel responsible for …
Solution Of Linear Ill-Posed Problems Using Overcomplete Dictionaries, Pawan Gupta
Solution Of Linear Ill-Posed Problems Using Overcomplete Dictionaries, Pawan Gupta
Electronic Theses and Dissertations
In this dissertation, we consider an application of overcomplete dictionaries to the solution of general ill-posed linear inverse problems. In the context of regression problems, there has been an enormous amount of effort to recover an unknown function using such dictionaries. While some research on the subject has been already carried out, there are still many gaps to address. In particular, one of the most popular methods, lasso, and its variants, is based on minimizing the empirical likelihood and unfortunately, requires stringent assumptions on the dictionary, the so-called, compatibility conditions. Though compatibility conditions are hard to satisfy, it is well …
Mode Coupling In Space-Division Multiplexed Systems, Huiyuan Liu
Mode Coupling In Space-Division Multiplexed Systems, Huiyuan Liu
Electronic Theses and Dissertations
Even though fiber-optic communication systems have been engineered to nearly approach the Shannon capacity limit, they still cannot meet the exponentially-growing bandwidth demand of the Internet. Space-division multiplexing (SDM) has attracted considerable attention in recent years due to its potential to address this capacity crunch. In SDM, the transmission channels support more than one spatial mode, each of which can provide the same capacity as a single-mode fiber. To make SDM practical, crosstalk among modes must be effectively managed. This dissertation presents three techniques for crosstalk management for SDM. In some cases such as intra-datacenter interconnects, even though mode crosstalk …
Nanoplasmonics In Two-Dimensional Dirac And Three-Dimensional Metallic Nanostructure Systems, Alireza Safaei
Nanoplasmonics In Two-Dimensional Dirac And Three-Dimensional Metallic Nanostructure Systems, Alireza Safaei
Electronic Theses and Dissertations
Surface plasmons are collective oscillation of electrons which are coupled to the incident electric field. Excitation of surface plasmon is a route to engineer the behavior of light in nanometer length scale and amplifying the light-matter interaction. This interaction is an outcome of near-field enhancement close to the metal surface which leads to plasmon damping through radiative decay to outgoing photons and nonradiative decay inside and on the surface of the material to create an electron-hole pair via interband or intraband Landau damping. Plasmonics in Dirac systems such as graphene show novel features due to massless electrons and holes around …
Design, Synthesis And Characterization Of Biomimetic, Bioinspired And Bio-Related Functional Polymers For Atmospheric Water Recovery, Abdullah Alqassar
Design, Synthesis And Characterization Of Biomimetic, Bioinspired And Bio-Related Functional Polymers For Atmospheric Water Recovery, Abdullah Alqassar
Electronic Theses and Dissertations
Atmospheric water recovery in changing environments has received wide attention in environmental science and engineering communities due to rapid population growth and frequent droughts. This study is focused on the design, synthesis, and characterization of biomimetic, bioinspired, and bio-related functional polymers (b3p) to help resolve the water supply issue especially in arid or semi-arid regions. It is aimed to develop unique synthetic methods to access well-defined polymers with the aid of nanomaterials and metal to produce next generation polymer materials for better atmospheric water recovery. The design of such new b3p is bioinspired by some skin materials of biological species …
Long-Term Carbon And Copper Impact On Nutrient Removal Via Green Sorption Media In Dynamic Linear Ditch Environments, Diana Ordonez
Long-Term Carbon And Copper Impact On Nutrient Removal Via Green Sorption Media In Dynamic Linear Ditch Environments, Diana Ordonez
Electronic Theses and Dissertations
Nutrient-laden stormwater runoff causes environmental and ecological impacts on receiving water bodies. Biosorption Activated Media (BAM) composed of the sand, tire crumb, and clay have been implemented in stormwater best management practices due to its ability to efficiently remove nutrients from stormwater runoff, such as in roadside linear ditches, via unique chemophysical and microbiological processes. In this study, a set of fixed-bed columns were set up to simulate some external forces in roadside linear ditches and examine how these external forces affect the performance of BAM. In our experiment, scenario 1 simulates the impact that animals such as tortoises, moles …
Novel Solid State Lasers Based On Volume Bragg Gratings, Evan Hale
Novel Solid State Lasers Based On Volume Bragg Gratings, Evan Hale
Electronic Theses and Dissertations
Since their invention in 1960, lasers have revolutionized modern technology, and tremendous amounts of innovation and development has gone into advancing their properties and efficiencies. This dissertation reports on further innovations by presenting novel solid state laser systems based on the volume Bragg gratings (VBGs) and the newly developed holographic phase mask (HPMs) for brightness enhancement, dual wavelength operation, and mode conversion. First, a new optical element was created by pairing the HPM with two surface gratings creating an achromatic holographic phase mask. This new optical device successfully performed transverse mode conversion of multiple narrow line laser sources operating from …
Cryogenic Performance Projections For Ultra-Small Oxide-Free Vertical-Cavity Surface-Emitting Lasers, Mina Bayat
Cryogenic Performance Projections For Ultra-Small Oxide-Free Vertical-Cavity Surface-Emitting Lasers, Mina Bayat
Electronic Theses and Dissertations
Small-sized vertical-cavity surface-emitting laser (VCSEL) may offer very low power consumption along with high reliability for cryogenic data transfer. Cryogenic data transfer has application in supercomputers and superconducting for efficient computing and also focal plane array cameras operating at 77 K, and at the lower temperature of 4 K for data extraction from superconducting circuits. A theoretical analysis is presented for 77 K and 4 K operation based on small cavity, oxide-free VCSEL sizes of 2 to 6 µm, that have been shown to operate efficiently at room temperature. Temperature dependent operation for optimally-designed VCSELs are studied by calculating the …
Artificial Magnetism And Topological Phenomena In Optics, Midya Parto
Artificial Magnetism And Topological Phenomena In Optics, Midya Parto
Electronic Theses and Dissertations
Recent years have witnessed intense research activities to effectively control the flow of photons using various classes of optical structures such as photonic crystals and metamaterials. In this regard, optics has benefited from concepts in condensed matter and solid-state physics, where similar problems concerning electronic wavefunctions arise. An important example of such correspondence is associated with the photon dynamics under the effect of an artificial magnetic field. This is especially important since photons, as neutral bosons, do not inherently interact with magnetic fields. One way to mitigate this issue is to exploit magneto-optical materials. However, as is well known, using …
High-Dynamic-Range Foveated Near-Eye Display System, Guanjun Tan
High-Dynamic-Range Foveated Near-Eye Display System, Guanjun Tan
Electronic Theses and Dissertations
Wearable near-eye display has found widespread applications in education, gaming, entertainment, engineering, military training, and healthcare, just to name a few. However, the visual experience provided by current near-eye displays still falls short to what we can perceive in the real world. Three major challenges remain to be overcome: 1) limited dynamic range in display brightness and contrast, 2) inadequate angular resolution, and 3) vergence-accommodation conflict (VAC) issue. This dissertation is devoted to addressing these three critical issues from both display panel development and optical system design viewpoints. A high-dynamic-range (HDR) display requires both high peak brightness and excellent dark …
Parameter Estimation Of Stochastic Models Against Probabilistic Temporal Logic Behavioral Specifications, Arfeen Khalid
Parameter Estimation Of Stochastic Models Against Probabilistic Temporal Logic Behavioral Specifications, Arfeen Khalid
Electronic Theses and Dissertations
The inherent behavioral variability exhibited by stochastic systems makes it a challenging task for human experts to manually analyze them. Computational modeling of such systems helps in investigating and predicting the behaviors of their underlying processes but at the same time introduces the presence of several unknown parameters. A key challenge faced in this scenario is to determine the values of these unknown parameters against known behavioral specifications. The solutions that have been presented so far estimate the parameters of a given model against a single specification whereas a correct model is expected to satisfy all the behavioral specifications when …
The Evaluation Of Classifier Performance On The Forensic Analysis Of Fire Debris And The Expansion Of The Substrate Database, Alyssa Allen
The Evaluation Of Classifier Performance On The Forensic Analysis Of Fire Debris And The Expansion Of The Substrate Database, Alyssa Allen
Electronic Theses and Dissertations
The current protocols in fire debris analysis rely on ignitable liquid pattern recognition and the identification of target compounds. These practices allow fire debris analysts to determine whether a sample contains or is absent of ignitable liquid residue and to classify that type of ignitable liquid based upon subjective thresholds. A statistical approach using computationally mixed datasets was devised in this research to generate an objective approach to the classification of fire debris samples and to determine error rates. Quadratic, linear, and partial least squares linear discriminant analysis (QDA, LDA, and PLS-DA) models were developed and evaluated to determine the …
Computational Imaging With Limited Photon Budget, Zheyuan Zhu
Computational Imaging With Limited Photon Budget, Zheyuan Zhu
Electronic Theses and Dissertations
The capability of retrieving the image/signal of interest from extremely low photon flux is attractive in scientific, industrial, and medical imaging applications. Conventional imaging modalities and reconstruction algorithms rely on hundreds to thousands of photons per pixel (or per measurement) to ensure enough signal-to-noise (SNR) ratio for extracting the image/signal of interest. Unfortunately, the potential of radiation or photon damage prohibits high SNR measurements in dose-sensitive diagnosis scenarios. In addition, imaging systems utilizing inherently weak signals as contrast mechanism, such as X-ray scattering-based tomography, or attosecond pulse retrieval from the streaking trace, entail prolonged integration time to acquire hundreds of …
Optical Sensing Of Structural Dynamics In Complex Media, Jose Rafael Guzman Sepulveda
Optical Sensing Of Structural Dynamics In Complex Media, Jose Rafael Guzman Sepulveda
Electronic Theses and Dissertations
Quantifying the structural dynamics of complex media is challenging because of the multiple temporal and spatial scales involved. Thanks to the ability to retrieve collective dynamics noninvasively, light scattering-based approaches are often the methods of choice. This dissertation discusses specific features of dynamic light scattering that utilizes spatio-temporal coherence gating. It is demonstrated that this optical fiber-based approach can operate over a large range of optical regimes and it has a number of unique capabilities such as an effective isolation of single scattering, a large sensitivity, and a high collection efficiency. Moreover, the approach also provides means for proper ensemble …
Collaborative Artificial Intelligence Algorithms For Medical Imaging Applications, Naji Khosravan
Collaborative Artificial Intelligence Algorithms For Medical Imaging Applications, Naji Khosravan
Electronic Theses and Dissertations
In this dissertation, we propose novel machine learning algorithms for high-risk medical imaging applications. Specifically, we tackle current challenges in radiology screening process and introduce cutting-edge methods for image-based diagnosis, detection and segmentation. We incorporate expert knowledge through eye-tracking, making the whole process human-centered. This dissertation contributes to machine learning, computer vision, and medical imaging research by: 1) introducing a mathematical formulation of radiologists level of attention, and sparsifying their gaze data for a better extraction and comparison of search patterns. 2) proposing novel, local and global, image analysis algorithms. Imaging based diagnosis and pattern analysis are "high-risk" Artificial Intelligence …
The Characterization Of Condom Lubricants And Personal Hygiene Products Using Dart-Tofms And Gc- Ms And The Investigation Of Gold Nanoparticle Behavior In Water And The Interaction With Blood Serum Proteins, Yasmine Moustafa
Electronic Theses and Dissertations
This dissertation is divided into two independent research projects. First, condom lubricants, sexual lubricants, and personal hygiene products (PHPs) were studied using direct analysis in real time-time-of-flight-mass spectrometry (DART-TOFMS) and gas chromatography-mass spectrometry (GC-MS). The purpose addressed the concern of perpetrators resorting to new tactics, i.e. using condoms to remove seminal fluid that could provide a DNA link to a suspect, leading to the need of the consideration of condom lubricants as pieces of sexual assault evidence. Due to condom lubricants having a chemical composition resembling PHPs, the investigation of both sample groups was analyzed to prevent false positives. Although …
Two Ramsey-Related Problems, Jingmei Zhang
Two Ramsey-Related Problems, Jingmei Zhang
Electronic Theses and Dissertations
Extremal combinatorics is one of the central branches of discrete mathematics and has experienced an impressive growth during the last few decades. It deals with the problem of determining or estimating the maximum or minimum possible size of a combinatorial structure which satisfies certain requirements. In this dissertation, we focus on studying the minimum number of edges of certain co-critical graphs. Given an integer r ≥ 1 and graphs G; H1; : : : ;Hr, we write → G (H1; : : : ;Hr) if every r-coloring of the edges of G contains a monochromatic copy of Hi in color …
Structure Of Reflectin Protein Probed By Solid-State Nuclear Magnetic Resonance, Tommy Boykin
Structure Of Reflectin Protein Probed By Solid-State Nuclear Magnetic Resonance, Tommy Boykin
Electronic Theses and Dissertations
An unusual protein found in squids, termed reflectin, possesses the unique ability for optical reflectivity and proton conductivity. Reflectin has the potential to become optically and electronically tunable, however, the molecular structure of reflectin has yet to be determined. Previous literature has considered using reflectin proteins as diffraction gratings, protonic transistors, and substrates for neural stem cell growth. Applying recombinant protein techniques, we purified the reflectin 4Ax4 protein. We determined the leucine, tryptophan, and threonine amino acids are in an ordered state by solid-state nuclear magnetic resonance (NMR). Knowing these ordered amino acids is possibly the key to understanding reflectin's …
Community-Based Coastal Restoration: Long Term Impacts On Habitats And People In Volusia County, Rachel Wimmer
Community-Based Coastal Restoration: Long Term Impacts On Habitats And People In Volusia County, Rachel Wimmer
Electronic Theses and Dissertations
Coastal habitats provide invaluable economic and ecosystem services. However, coastlines are eroding at increasing rates due to anthropogenic and climate driven changes. Grey and green infrastructure solutions have been proposed to retard the decay of coastlines, with oysters serving as a popular living shoreline. Three community-based stabilizations that implemented living shorelines and engaged local communities in restoration efforts over the past decade in Volusia County were revisited to determine if they were successful and if they produced positive public perceptions of success. Chicken Island, which was restored after waves, boat wakes, tides, and adverse weather altered the natural shoreline, had …
An Assessment Of Biosorption Activated Media For The Removal Of Pollutants In Up-Flow Stormwater Treatment Systems, Andrew Hood
An Assessment Of Biosorption Activated Media For The Removal Of Pollutants In Up-Flow Stormwater Treatment Systems, Andrew Hood
Electronic Theses and Dissertations
Nitrogen and phosphorus are often the limiting nutrients for marine and freshwater systems respectively. Additionally, stormwater often contains elevated levels of pathogens which can pollute the receiving water body and impact reuse applications [1-4]. The reduction of limiting nutrients and pathogens is a common primary target for stormwater best management practices (BMPs) [5]. Traditional BMPs, such as retention/detention treatment ponds require large footprints and may not be practical in ultra-urban environments where above ground space is limited. Upflow filters utilizing biosorption activated media (BAM) that can be placed underground offer a small footprint alternative. Additionally, BAM upflow filters can be …
Visual-Textual Video Synopsis Generation, Aidean Sharghi Karganroodi
Visual-Textual Video Synopsis Generation, Aidean Sharghi Karganroodi
Electronic Theses and Dissertations
In this dissertation we tackle the problem of automatic video summarization. Automatic summarization techniques enable faster browsing and indexing of large video databases. However, due to the inherent subjectivity of the task, no single video summarizer fits all users unless it adapts to individual user's needs. To address this issue, we introduce a fresh view on the task called "Query-focused'' extractive video summarization. We develop a supervised model that takes as input a video and user's preference in form of a query, and creates a summary video by selecting key shots from the original video. We model the problem as …
Broadband Mid-Infrared Frequency Combs Generated Via Frequency Division, Qitian Ru
Broadband Mid-Infrared Frequency Combs Generated Via Frequency Division, Qitian Ru
Electronic Theses and Dissertations
Frequency combs have revolutionized metrology and demonstrated numerous applications in science and technology. Combs operating in the mid-infrared region could be beneficial for molecular spectroscopy for several reasons. First, numerous molecules have their spectroscopic signatures in this region. Furthermore, the atmospheric window (3-5μm and 8-14μm) is located here. Additionally, a mid-infrared frequency comb could be employed as a diagnostic tool for the many components of human breath, as well as for detection of harmful gases and contaminants in the atmosphere. In this thesis, I used synchronously pumped subharmonic optical parametric oscillators (OPOs) operating at degeneracy to produce ultra-broadband outputs near …
Blockchain-Driven Secure And Transparent Audit Logs, Ashar Ahmad
Blockchain-Driven Secure And Transparent Audit Logs, Ashar Ahmad
Electronic Theses and Dissertations
In enterprise business applications, large volumes of data are generated daily, encoding business logic and transactions. Those applications are governed by various compliance requirements, making it essential to provide audit logs to store, track, and attribute data changes. In traditional audit log systems, logs are collected and stored in a centralized medium, making them prone to various forms of attacks and manipulations, including physical access and remote vulnerability exploitation attacks, and eventually allowing for unauthorized data modification, threatening the guarantees of audit logs. Moreover, such systems, and given their centralized nature, are characterized by a single point of failure. To …
Correctness And Progress Verification Of Non-Blocking Programs, Christina Peterson
Correctness And Progress Verification Of Non-Blocking Programs, Christina Peterson
Electronic Theses and Dissertations
The progression of multi-core processors has inspired the development of concurrency libraries that guarantee safety and liveness properties of multiprocessor applications. The difficulty of reasoning about safety and liveness properties in a concurrent environment has led to the development of tools to verify that a concurrent data structure meets a correctness condition or progress guarantee. However, these tools possess shortcomings regarding the ability to verify a composition of data structure operations. Additionally, verification techniques for transactional memory evaluate correctness based on low-level read/write histories, which is not applicable to transactional data structures that use a high-level semantic conflict detection. In …
The Schrödinger Equation With Coulomb Potential Admits No Exact Solutions, Ilia Toli
The Schrödinger Equation With Coulomb Potential Admits No Exact Solutions, Ilia Toli
Electronic Theses and Dissertations
We prove that the Schrödinger equation with the electrostatic potential energy expressed by the Coulomb potential does not admit exact solutions for three or more bodies. It follows that the exact solutions proposed by Fock [1–3] are flawed. The Coulomb potential is the problem. Based on the classical (non-quantum) principle of superposition, the Coulomb potential of a system of many particles is assumed to be the sum of all the pairwise Coulomb potentials. We prove that this is not accurate. The Coulomb potential being a hyperbolic (not linear) function, the superposition principle does not apply. The Schrödinger equation as studied …
Multi-Modal Interfaces For Sensemaking Of Graph-Connected Datasets, Anthony Wehrer
Multi-Modal Interfaces For Sensemaking Of Graph-Connected Datasets, Anthony Wehrer
Electronic Theses and Dissertations
The visualization of hypothesized evolutionary processes is often shown through phylogenetic trees. Given evolutionary data presented in one of several widely accepted formats, software exists to render these data into a tree diagram. However, software packages commonly in use by biologists today often do not provide means to dynamically adjust and customize these diagrams for studying new hypothetical relationships, and for illustration and publication purposes. Even where these options are available, there can be a lack of intuitiveness and ease-of-use. The goal of our research is, thus, to investigate more natural and effective means of sensemaking of the data with …
Scalable Network Design And Management With Decentralized Software-Defined Networking, Kuldip Singh Atwal
Scalable Network Design And Management With Decentralized Software-Defined Networking, Kuldip Singh Atwal
Electronic Theses and Dissertations
Network softwarization is among the most significant innovations of computer networks in the last few decades. The lack of uniform and programmable interfaces for network management led to the design of OpenFlow protocol for the university campuses and enterprise networks. This breakthrough coupled with other similar efforts led to an emergence of two complementary but independent paradigms called software-defined networking (SDN) and network function virtualization (NFV). As of this writing, these paradigms are becoming the de-facto norms of wired and wireless networks alike. This dissertation mainly addresses the scalability aspect of SDN for multiple network types. Although centralized control and …