Open Access. Powered by Scholars. Published by Universities.®
- Discipline
-
- Engineering (79)
- Mathematics (31)
- Numerical Analysis and Computation (29)
- Other Applied Mathematics (26)
- Computer Sciences (24)
-
- Electrical and Computer Engineering (22)
- Operations Research, Systems Engineering and Industrial Engineering (22)
- Statistics and Probability (22)
- Aerospace Engineering (17)
- Dynamic Systems (16)
- Ordinary Differential Equations and Applied Dynamics (16)
- Partial Differential Equations (16)
- Signal Processing (16)
- Life Sciences (15)
- Medicine and Health Sciences (15)
- Operational Research (15)
- Applied Statistics (13)
- Non-linear Dynamics (13)
- Physics (13)
- Control Theory (9)
- Statistical Models (9)
- Analysis (7)
- Biostatistics (7)
- Business (7)
- Environmental Sciences (7)
- Computer Engineering (6)
- Numerical Analysis and Scientific Computing (6)
- Public Health (6)
- Institution
- Keyword
-
- Algorithms (8)
- Differential equations (8)
- Mathematics (7)
- Mathematical modeling (6)
- Mathematical models (6)
-
- Optimization (6)
- Wavelets (Mathematics) (6)
- Image processing (5)
- Numerical analysis (5)
- Machine learning (4)
- Mathematical optimization (4)
- Monte Carlo method (4)
- Programming (Mathematics) (4)
- Signal processing--Digital techniques (4)
- Agent-based model (3)
- Chaos (3)
- Deep Learning (3)
- Finite element method (3)
- Graph theory (3)
- Groundwater--Pollution (3)
- Interpolation (3)
- Neural Networks (3)
- Neural networks (Computer science) (3)
- Parameter estimation (3)
- Partial differential equations (3)
- Probability (3)
- Sensitivity analysis (3)
- Stochastic processes (3)
- Target acquisition (3)
- Time series (3)
Articles 151 - 180 of 320
Full-Text Articles in Applied Mathematics
Analysis Of Temperature And Humidity Effects On Horizontal Photovoltaic Panels, Corey J. Booker
Analysis Of Temperature And Humidity Effects On Horizontal Photovoltaic Panels, Corey J. Booker
Theses and Dissertations
The United States Air Force seeks to address power grid vulnerability and bolster energy resilience through the use of renewable energy sources. Air Force Institute of Technology engineers designed and manufactured control systems to monitor power production from the most widely-used silicon-based solar cells at 38 testing locations around the globe spanning the majority of climate types. Researchers conducted multivariate regression analysis to establish a statistical relationship between photovoltaic power output, ambient temperature, and humidity pertaining to monocrystalline and polycrystalline photovoltaic panels. Formulated models first characterized power output globally, then by specific climate type with general inaccuracy. Location-specific models are …
Analysis Of A Medical Center's Cardiac Risk Screening Protocol Using Propensity Score Matching, Jake E. Johnson
Analysis Of A Medical Center's Cardiac Risk Screening Protocol Using Propensity Score Matching, Jake E. Johnson
Theses and Dissertations
Researchers at the University of Maryland Medical Center in Baltimore have developed a cardiac risk stratification protocol in the hopes of reducing the time-from arrival-to-first-operation for geriatric orthopedic patients. They collected observational data for two years prior to and following the October 2014 implementation of the new screening protocol. Therefore, advanced analytical techniques are required to isolate the treatment effect of the new screening protocol. Propensity score matching (PSM) is used to handle the observational data in order to reduce the bias attributable to the confounding covariates. In addition to PSM, various regression techniques are used to help the researchers …
Lightning Prediction Using Artificial Neural Networks And Electric Field Mill Data, Daniel E. Hill
Lightning Prediction Using Artificial Neural Networks And Electric Field Mill Data, Daniel E. Hill
Theses and Dissertations
Electric Field Mills (EFMs) located in the region surrounding Cape Canaveral record the electrification of the atmosphere near them. Research studying how these sensors could improve lightning warnings has had mixed results. This paper used a Convolutional Recurrent Neural Network (CRNN) and data from 30 EFMs from May-July of 2012-2016. The mean was calculated for every 60 second period and 30 minutes of this summarized data was used to create a lightning prediction with a warning period of 15 minutes. This method achieved a True Positive Rate (TPR) of 77.6%, a False Positive Rate (FPR) of 8.3%, a False Discovery …
Modeling Multimodal Failure Effects Of Complex Systems Using Polyweibull Distribution, Daniel A. Timme
Modeling Multimodal Failure Effects Of Complex Systems Using Polyweibull Distribution, Daniel A. Timme
Theses and Dissertations
The Department of Defense (DoD) enlists multiple complex systems across each of their departments. Between the aging systems going through an overhaul and emerging new systems, quality assurance to complete the mission and secure the nation‘s objectives is an absolute necessity. The U.S. Air Force‘s increased interest in Remotely Piloted Aircraft (RPA) and the Space Warfighting domain are current examples of complex systems that must maintain high reliability and sustainability in order to complete missions moving forward. DoD systems continue to grow in complexity with an increasing number of components and parts in more complex arrangements. Bathtub-shaped hazard functions arise …
Quasi-Static Nonlinear Analysis Of A Celestial Icosahedron Shaped Vacuum Lighter Than Air Vehicle, Kyle D. Moore
Quasi-Static Nonlinear Analysis Of A Celestial Icosahedron Shaped Vacuum Lighter Than Air Vehicle, Kyle D. Moore
Theses and Dissertations
Due to the many drawbacks associated with a traditional lighter than air vehicle (LTAV), there is a desire for a LTAV which generates lift from an internal vacuum. To date, two feasible designs (the icosahedron and the hexakis icosahedron) for this so called vacuum lighter than air vehicle (VLTAV) have been studied at the Air Force Institute of Technology (AFIT). This research looks to show the feasibility of a new design for a VLTAV, the celestial icosahedron. This research includes a boundary condition study which proves the symmetric nature of the celestial icosahedron's frame with laterally constrained and unconstrained vertices. …
Material Thermal Property Estimation Of Fibrous Insulation: Heat Transfer Modeling And The Continuous Genetic Algorithm, Elora Frye
Theses and Dissertations
Material thermal properties are highly sought after to better understand the performance of a material under particular conditions. As new materials are created, their physical properties will determine their performance for various applications. These properties have been estimated using many techniques including experimental testing, numerical modeling, and a combination of both. Existing methods can be time consuming, thus, a time-efficient and precise method to estimate these thermal properties was desired. A one-dimensional finite difference numerical model was developed to replicate the heat transfer through an experimental apparatus. A combination of this numerical model and the Continuous Genetic Algorithm optimization technique …
Developing A Cyberterrorism Policy: Incorporating Individual Values, Osama Bassam J. Rabie
Developing A Cyberterrorism Policy: Incorporating Individual Values, Osama Bassam J. Rabie
Theses and Dissertations
Preventing cyberterrorism is becoming a necessity for individuals, organizations, and governments. However, current policies focus on technical and managerial aspects without asking for experts and non-experts values and preferences for preventing cyberterrorism. This study employs value focused thinking and public value forum to bare strategic measures and alternatives for complex policy decisions for preventing cyberterrorism. The strategic measures and alternatives are per socio-technical process.
Penalized Mixed-Effects Ordinal Response Models For High-Dimensional Genomic Data In Twins And Families, Amanda E. Gentry
Penalized Mixed-Effects Ordinal Response Models For High-Dimensional Genomic Data In Twins And Families, Amanda E. Gentry
Theses and Dissertations
The Brisbane Longitudinal Twin Study (BLTS) was being conducted in Australia and was funded by the US National Institute on Drug Abuse (NIDA). Adolescent twins were sampled as a part of this study and surveyed about their substance use as part of the Pathways to Cannabis Use, Abuse and Dependence project. The methods developed in this dissertation were designed for the purpose of analyzing a subset of the Pathways data that includes demographics, cannabis use metrics, personality measures, and imputed genotypes (SNPs) for 493 complete twin pairs (986 subjects.) The primary goal was to determine what combination of SNPs and …
Delay Differential Equations And Their Application To Micro Electro Mechanical Systems, Asset Ospanov
Delay Differential Equations And Their Application To Micro Electro Mechanical Systems, Asset Ospanov
Theses and Dissertations
Delay differential equations have a wide range of applications in engineering. This work is devoted to the analysis of delay Duffing equation, which plays a crucial role in modeling performance on demand Micro Electro Mechanical Systems (MEMS). We start with the stability analysis of a linear delay model. We also show that in certain cases the delay model can be efficiently approximated with a much simpler model without delay. We proceed with the analysis of a non-linear Duffing equation. This model is a significantly more complex mathematical model. For instance, the existence of a periodic solution for this equation is …
Heterogeneous Anisotropy Index And Scaling In Multiphase Random Polycrystals, Muhammad Ridwan Murshed
Heterogeneous Anisotropy Index And Scaling In Multiphase Random Polycrystals, Muhammad Ridwan Murshed
Theses and Dissertations
Under consideration is the finite-size scaling of elastic properties in single and two-phase random polycrystals with individual grains belonging to any crystal class (from cubic to triclinic). These polycrystals are generated by Voronoi tessellations with varying grain sizes and volume fractions. By employing variational principles in elasticity, we introduce the notion of a 'Heterogeneous Anisotropy Index' and investigate its role in the scaling of elastic properties at finite mesoscales. The index turns out to be a function of 43 variables, 21 independent components for each phase and the volume fraction of either phase. Furthermore, the relationship between Heterogeneous Anisotropy Index …
Initial{Boundary And Nonlocal Boundary Value Problems For Higher Order Nonlinear Hyperbolic Equations With Two Independent Variables, Raja Ben-Rabha
Initial{Boundary And Nonlocal Boundary Value Problems For Higher Order Nonlinear Hyperbolic Equations With Two Independent Variables, Raja Ben-Rabha
Theses and Dissertations
Boundary value problems in a characteristic rectangle for nonlinear hyperbolic equations of higher order are considered. The concept of strong well–posedness of a boundary value problem is introduced. For initial–boundary value problems there are established: (i) Necessary and sufficient conditions of strong well–posedness; (ii) Unimprovable sufficient conditions of local and global solvability; (iii) Effective sufficient conditions of solvability of two–point, multi–point, periodic and Dirichlet type problems; (iv) Sharp a priori estimates of solutions of ill–posed initial–boundary value problems; (v) Unimprovable conditions guaranteeing unique solvability of ill–posed initial–boundary value problems. For nonlocal boundary value problems there are established: (i) Necessary and …
Superconvergence Of A Modified Weak Galerkin Approximation For Second Order Elliptic Problems By L^2 Projection Method, Betul Bogrek
Superconvergence Of A Modified Weak Galerkin Approximation For Second Order Elliptic Problems By L^2 Projection Method, Betul Bogrek
Theses and Dissertations
In this dissertation, the general superconvergence result of a modified weak Galerkin finite element approximation for the second order elliptic problem by using L^2 projection method is introduced. The novel weak Galerkin finite element method, which was first proposed and analyzed by Wang J. and Ye X., uses the appropriately defined weak functions and discrete weak gradients on arbitrary shapes for higher order polynomial functions. The modified weak Galerkin finite element method was introduced by Wang X. & et al. It reduces the number of unknowns by modifying weak functions from the weak Galerkin finite element method. The superconvergence for …
On The Classification Of The Second Minimal Orbits Of The Continuous Endomorphisms On The Real Line And Universality In Chaos, Naveed H. Iqbal
On The Classification Of The Second Minimal Orbits Of The Continuous Endomorphisms On The Real Line And Universality In Chaos, Naveed H. Iqbal
Theses and Dissertations
This dissertation presents full classification of second minimal odd periodic orbits of a continuous endomorphisms on the real line. A (2k + 1)-periodic orbit (k ≥ 3) is called second minimal for the map f , if 2k−1 is a minimal period of f in the Sharkovskii ordering. We prove that there are 4k−3 types of second minimal (2k+1)-orbits, each characterized with unique cyclic permutation and directed graph of transitions with accuracy up to inverses. The result is applied to the problem on the distribution of periodic windows within the chaotic regime of the bifurcation diagram of the one-parameter family …
The Air Force Fitness Test: Creating New Fitness Assessment Charts Using Waist To Height Ratios, John R. Griffith
The Air Force Fitness Test: Creating New Fitness Assessment Charts Using Waist To Height Ratios, John R. Griffith
Theses and Dissertations
The Air Force currently uses AFI 36-2905 for fitness standards and evaluation, but no study to our knowledge has evaluated these standards using large databases. Using a 5.38 million record database from the Air Force Fitness Management System, we evaluated how the abdominal circumference, body mass index (BMI), waist to height ratio (WtHR), and height to weight ratio correlated to fitness as assessed by the 1.5 mile aerobic run in the Air Force Fitness Test. Whether individually or adjusting for age group and gender, WtHR performed better that the rest with an average rank score of 1.1 with a relative …
The Effects Of Disturbance And Species Specific Interactions On Diversity In An Agent Based Forest Simulation, Matthew E. Mills
The Effects Of Disturbance And Species Specific Interactions On Diversity In An Agent Based Forest Simulation, Matthew E. Mills
Theses and Dissertations
In ecology literature, there is much data which suggests that conspecific negative density dependence (CNDD) and abiotic disturbances increase biodiversity in forests. This thesis elucidates the notion that not only do these two forces increase diversity, but they may also interact with one another in order to achieve higher levels of biodiversity. Abiotic disturbances, like fires and hurricanes, can indirectly impact conspecific effects because when these forces remove individuals from the landscape, the role of the conspecific effects will change. The interaction of these two factors in biodiversity are explored in an agent based forest simulation through a resource surface. …
Mathematical Models Of The Inflammatory Response In The Lungs, Sarah B. Minucci
Mathematical Models Of The Inflammatory Response In The Lungs, Sarah B. Minucci
Theses and Dissertations
Inflammation in the lungs can occur for many reasons, from bacterial infections to stretch by mechanical ventilation. In this work we compare and contrast various mathematical models for lung injuries in the categories of acute infection, latent versus active infection, and particulate inhalation. We focus on systems of ordinary differential equations (ODEs), agent-based models (ABMs), and Boolean networks. Each type of model provides different insight into the immune response to damage in the lungs. This knowledge includes a better understanding of the complex dynamics of immune cells, proteins, and cytokines, recommendations for treatment with antibiotics, and a foundation for more …
Series Solutions Of Polarized Gowdy Universes, Doniray Brusaferro
Series Solutions Of Polarized Gowdy Universes, Doniray Brusaferro
Theses and Dissertations
Einstein's field equations are a system of ten partial differential equations. For a special class of spacetimes known as Gowdy spacetimes, the number of equations is reduced due to additional structure of two dimensional isometry groups with mutually orthogonal Killing vectors. In this thesis, we focus on a particular model of Gowdy spacetimes known as the polarized T3 model, and provide an explicit solution to Einstein's equations.
Computational Fluid Dynamics In A Terminal Alveolated Bronchiole Duct With Expanding Walls: Proof-Of-Concept In Openfoam, Jeremy Myers
Computational Fluid Dynamics In A Terminal Alveolated Bronchiole Duct With Expanding Walls: Proof-Of-Concept In Openfoam, Jeremy Myers
Theses and Dissertations
Mathematical Biology has found recent success applying Computational Fluid Dynamics (CFD) to model airflow in the human lung. Detailed modeling of flow patterns in the alveoli, where the oxygen-carbon dioxide gas exchange occurs, has provided data that is useful in treating illnesses and designing drug-delivery systems. Unfortunately, many CFD software packages have high licensing fees that are out of reach for independent researchers. This thesis uses three open-source software packages, Gmsh, OpenFOAM, and ParaView, to design a mesh, create a simulation, and visualize the results of an idealized terminal alveolar sac model. This model successfully demonstrates that OpenFOAM can be …
Network Analytics For The Mirna Regulome And Mirna-Disease Interactions, Joseph Jayakar Nalluri
Network Analytics For The Mirna Regulome And Mirna-Disease Interactions, Joseph Jayakar Nalluri
Theses and Dissertations
miRNAs are non-coding RNAs of approx. 22 nucleotides in length that inhibit gene expression at the post-transcriptional level. By virtue of this gene regulation mechanism, miRNAs play a critical role in several biological processes and patho-physiological conditions, including cancers. miRNA behavior is a result of a multi-level complex interaction network involving miRNA-mRNA, TF-miRNA-gene, and miRNA-chemical interactions; hence the precise patterns through which a miRNA regulates a certain disease(s) are still elusive. Herein, I have developed an integrative genomics methods/pipeline to (i) build a miRNA regulomics and data analytics repository, (ii) create/model these interactions into networks and use optimization techniques, motif …
Robustness Of The Potential And Flux Landscapes In Fission Yeast Cell Cycle Networks, Xiaosheng Luo
Robustness Of The Potential And Flux Landscapes In Fission Yeast Cell Cycle Networks, Xiaosheng Luo
Theses and Dissertations
Using fission yeast cell cycle as an example, we uncovered that the non-equilibrium network dynamics and global properties are determined by two essential features: the potential landscape and the flux landscape. While potential landscape quantifies the probabilities of different states forming hills and valleys, the flux landscape quantifies the probability fluxes of different loops flowing through states. These two landscapes can be quantified through the decomposition of the dynamics into the detailed balance preserving part and detailed balance breaking non-equilibrium part. While the funneled potential landscape is often crucial for the stability of the single attractor networks, we have uncovered …
Synergistic Effects Of Phase Folding And Wavelet Denoising With Applications In Light Curve Analysis, Andrew M. Armstrong
Synergistic Effects Of Phase Folding And Wavelet Denoising With Applications In Light Curve Analysis, Andrew M. Armstrong
Theses and Dissertations
The growing size of cosmological data sets is causing the current human-centric approach to cosmology to become impractical. Autonomous data analysis techniques need to be developed in order to advance the field of cosmology. This research examines the benefits of combining two signal analysis techniques, namely phase folding and wavelet denoising, into a newly-developed suite of autonomous light curve analysis tools which includes aspects of component extraction and period detection. The improvements these tools provide, with respect to autonomy and signal quality, are demonstrated using both simulated and real-world light curve data. Although applied to light curve data, the suite …
Time Domain Analysis Of Electromagnetic Scattering From Multiple Cavities Embedded In A Ground Plane, Richard P. Uber
Time Domain Analysis Of Electromagnetic Scattering From Multiple Cavities Embedded In A Ground Plane, Richard P. Uber
Theses and Dissertations
This work examines the scattered fields produced when a transient wave is reflected from an infinite perfect electric conductor (PEC) ground plane with multiple embedded cavities. Incident and reflected waves will be decomposed into transverse magnetic to the z direction (TMz) and transverse electric to the z direction (TEz) polarizations, with primary focus given to the TMz. Cavities may be unfilled, partially filled, or fully filled with non-magnetic dielectric material and no assumptions are made regarding similarity, regularity, or periodicity. The Newmark method is used to discretize time and a variational formulation is presented for each time step. The principle …
A Logistic Regression And Markov Chain Model For The Prediction Of Nation-State Violent Conflicts And Transitions, Nicholas Shallcross
A Logistic Regression And Markov Chain Model For The Prediction Of Nation-State Violent Conflicts And Transitions, Nicholas Shallcross
Theses and Dissertations
Using open source data, this research formulates and constructs a suite of statistical models that predict future transitions into and out of violent conflict and forecasts the regional and global incidences of violent conflict over a ten-year time horizon. A total of thirty predictor variables are tested and evaluated for inclusion in twelve conditional logistic regression models, which calculate the probability that a nation will transition from its current conflict state, either In Conflict or Not in Conflict, to a new state in the following year. These probabilities are then used to construct a series of nation-specific Markov chain models …
Diagnosing Autism Spectrum Disorder Through Brain Functional Magnetic Resonance Imaging, Kyle A. Palko
Diagnosing Autism Spectrum Disorder Through Brain Functional Magnetic Resonance Imaging, Kyle A. Palko
Theses and Dissertations
Autism spectrum disorder (ASD) is a neurodevelopmental condition that can be debilitating to social functioning. Previous functional Magnetic Resonance Imaging (fMRI) classification studies have included only small subject sample sizes (n 50) and have seen high classification accuracy. The recent release of the Autism Brain Imaging Data Exchange (ABIDE) provides fMRI data for over 1,100 subjects. In our research, we derive a subject's functional network connectivity (FNC) from their fMRI data and develop a regularized logistic classifier to determine whether a subject has autism. We obtained up to 65% classification accuracy, similar to other studies using the ABIDE dataset, suggesting …
Radial Basis Function Based Quadrature Over Smooth Surfaces, Maloupu L. Watts
Radial Basis Function Based Quadrature Over Smooth Surfaces, Maloupu L. Watts
Theses and Dissertations
The numerical approximation of denite integrals, or quadrature, often involves the construction of an interpolant of the integrand and subsequent integration of the interpolant. It is natural to rely on polynomial interpolants in the case ofone dimension; however, extension of integration of polynomial interpolants to two or more dimensions can be costly andunstable. A method for computing surface integrals on the sphere is detailed in the literature (Reeger and Fornberg,Studies in Applied Mathematics, 2016). The method uses local radial basis function (RBF) interpolation to reducecomputational complexity when generating quadrature weights for the particular node set. This thesis expands upon thesame …
A Weak Galerkin Method For Parabolic Equations, Yajie Yu
A Weak Galerkin Method For Parabolic Equations, Yajie Yu
Theses and Dissertations
Parabolic equations have very broad applications in physics and engineering, such as heat diffusion and ocean acoustic propagation. Here we consider the 2D case with time dependent equations. Many numerical methods have been proposed to solve them, such as discontinuous Galerkin method, hybridized Galerkin method and so on. A weak Galerkin method is introduced by Dr. Wang and Dr. Ye by employing totally discontinuous functions in approximation space and an innovatively defined weak gradient operator which provide desirable flexibilities.In this thesis, we apply this method to solve parabolic equations. This method also has the energy conserva- tion property. Both continuous …
An Analysis Of The Impact Of The Csu Peer Leader Program On Student Performance In 2014-2015, Harrison E. Sharitt
An Analysis Of The Impact Of The Csu Peer Leader Program On Student Performance In 2014-2015, Harrison E. Sharitt
Theses and Dissertations
In efforts to retain students and increase student performance, Columbus State implemented a Peer Leader program. With access to archival data on the CSU Peer Leader Program, the goal of this project was to determine if the program at CSU had a significant impact on students’ course performance. The impact of the program was assessed by performing multiple regression analyses and ANOVA. Preliminary results showed that Columbus State’s Peer Leader program had a small, but statistically significant, positive impact on students’ final course grades.
Optimal Control And Its Application To The Life-Cycle Savings Problem, Tracy A. Taylor
Optimal Control And Its Application To The Life-Cycle Savings Problem, Tracy A. Taylor
Theses and Dissertations
Throughout the course of this thesis, we give an introduction to optimal control theory and its necessary conditions, prove Pontryagin's Maximum Principle, and present the life-cycle saving under uncertain lifetime optimal control problem. We present a very involved sensitivity analysis that determines how a change in the initial wealth, discount factor, or relative risk aversion coefficient may affect the model the terminal depletion of wealth time, optimal consumption path, and optimal accumulation of wealth path. Through simulation of the life-cycle saving under uncertain lifetime model, we are not only able to present the model dynamics through time, but also to …
A Two Host Species Stage-Structured Model Of West Nile Virus Transmission, Taylor A. Beebe
A Two Host Species Stage-Structured Model Of West Nile Virus Transmission, Taylor A. Beebe
Theses and Dissertations
We develop and evaluate a novel host-vector model of West Nile virus (WNV) transmission that incorporates multiple avian host species and host stage-structure (juvenile and adult stages), with both species-specific and stage-specific biting rates of vectors on hosts. We use this model to explore WNV transmission dynamics that occur between vectors and multiple structured host populations as a result of heterogeneous biting rates. Our analysis shows that increased exposure of juvenile hosts results in earlier, more intense WNV transmission when compared to the effects of differential host species exposure, regardless of other parameter values. We also find that, in addition …
A Study Of The Effect Of Harvesting On A Discrete System With Two Competing Species, Rebecca G. Clark
A Study Of The Effect Of Harvesting On A Discrete System With Two Competing Species, Rebecca G. Clark
Theses and Dissertations
This is a study of the effect of harvesting on a system with two competing species. The system is a Ricker-type model that extends the work done by Luis, Elaydi, and Oliveira to include the effect of harvesting on the system. We look at the uniform bound of the system as well as the isoclines and perform a stability analysis of the equilibrium points. We also look at the effects of harvesting on the stability of the system by looking at the bifurcation of the system with respect to harvesting.