Physical Sciences and Mathematics Commons^™

Dynamics Of Coupled Particles In A Time-Dependent, Double-Gyre Flow, Manuel Albrizzio

Theses, Dissertations and Culminating Projects

We consider a time-dependent, wind-driven, stochastic double-gyre flow, and investigate the interaction between the flow and coupled particles operating within the flow. It is known that noise can cause individual particles to escape from one gyre to another gyre. By computing the Lagrangian coherent structures (LCS) of the system, one can determine low and high probability regions of particle escape. We adjust the coupling between two particles, and study the effect on particle escape for a variety of initial conditions and noise intensities.

Understanding The Flow Structure Of Low Reynolds Number Flows, Albert Jarvis

Theses, Dissertations and Culminating Projects

Ocean flows and the mechanisms by which their contents are organized has been a longstanding area of interest in applied mathematics. In recent years, a new theory has been developed to identify the structures responsible for the organization of fluid particles within complex geophysical flows. This theory is known as the theory of Lagrangian Coherent Structures (LCS) and details which structures are responsible for the organization of the flow and how to identify them. Being able to identify these LCS in real time has far reaching implications ranging from developing strategies for search and rescue missions to identifying the best …

Conformal Mapping Improvement Of The Boundary Element Method Solution For Underground Water Flow In A Domain With A Very Singular Boundary, Megan Romero

UNLV Theses, Dissertations, Professional Papers, and Capstones

Numerical solutions using a Boundary Element Method (BEM) for a confined flow in a very singular finite domain are developed. Typically, in scientific journal publications, authors avoid domains with many and more malignant singularities due to the extremely big and difficult to estimate errors in the numerical calculations. Using exact Conformal Mapping solutions for simplified domains with the same singularity as in the original domain, this problem can be solved numerically with improvements introduced by Conformal Mapping solutions. Firstly, to experiment with improving the BEM solution by Conformal Mapping, a domain inside a rectangle is considered. The exact solution inside …

Full Field Computing For Elastic Pulse Dispersion In Inhomogeneous Bars, A. Berezovski, R. Kolman, M. Berezovski, D. Gabriel, V. Adamek

Publications

In the paper, the finite element method and the finite volume method are used in parallel for the simulation of a pulse propagation in periodically layered composites beyond the validity of homogenization methods. The direct numerical integration of a pulse propagation demonstrates dispersion effects and dynamic stress redistribution in physical space on example of a one-dimensional layered bar. Results of numerical simulations are compared with analytical solution constructed specifically for the considered problem. Analytical solution as well as numerical computations show the strong influence of the composition of constituents on the dispersion of a pulse in a heterogeneous bar and …

New Mechanism For Accelerated Removal Of Excess Radiogenic Heat, Russell Humphreys

Proceedings of the International Conference on Creationism

In a technical paper (Humphreys, 2014), I presented Biblical and scientific evidence that (a) space is a physical material that we do not perceive, (b) this fabric of space, and objects within it, are thin in a 4th spatial direction we do not ordinarily perceive, and (c) the fabric is surrounded by a hyperspace of four spatial dimensions. End note 27 of the paper explained that light emitted by objects within the fabric ordinarily would be constrained to travel entirely within the fabric. The end note also proposed that under certain extraordinary conditions the Bible calls the opening of the …

Finite Element Analysis Of Large Body Deformation Induced By A Catastrophic Near Impact Event, Denver W. Seely, Andrew Bowman, Heechen Cho, Mark Horstemeyer

Proceedings of the International Conference on Creationism

Finite element simulations of near impacts of terrestrial bodies are presented to investigate possible deformation behavior induced by a massive body during the creation week and/or Genesis Flood. Using the universal law of gravitation, a gravitationally loaded objected is subjected to the ‘pull’ of a near passing fly-by object, and the resulting surface deformations are studied. An Internal State Variable (ISV) pressure dependent plasticity model for silicate rocks (Cho et al., 2018) is used to model the deformation behavior and to capture the history effects involved during the complex surface loading/unloading found in a near impact event. The model is …

On Some Ergodic Impulse Control Problems With Constraint, J. L. Menaldi, Maurice Robin

Mathematics Faculty Research Publications

This paper studies the impulse control of a general Markov process under the average (or ergodic) cost when the impulse instants are restricted to be the arrival times of an exogenous process, and this restriction is referred to as a constraint. A detailed setting is described, a characterization of the optimal cost is obtained as a solution of an HJB equation, and an optimal impulse control is identified.

Calculus Of The Impossible: Review Of The Improbability Principle (2014) By David Hand And The Logic Of Miracles (2018) By Lásló Mérő, Samuel L. Tunstall

Numeracy

David J. Hand. 2014. The Improbability Principle: Why Coincidences, Miracles, and Rare Events Happen Every Day (New York, NY: Scientific American/Farrar, Straus and Giroux) 288 pp. ISBN: 978-0374175344.

Lásló Mérő. 2018. The Logic of Miracles: Making Sense of Rare, Really Rare, and Impossibly Rare Events (New Haven, CT: Yale University Press) 288 pp. ISBN: 978-0300224153.

David Hand and Lásló Mérő both grapple with the occurrence of seemingly impossible events in these two popular science books. In this comparative review, I describe the two books, and explain why I prefer Hand's treatment of the impossible.

Curve Tracking Control Under State Constraints And Uncertainties, Robert Kelly Sizemore

LSU Doctoral Dissertations

We study a class of steering control problems for free-moving particles tracking a curve in the plane and also in a three-dimensional environment, which are central problems in robotics. In the two-dimensional case, we provide adaptive controllers for curve tracking under unknown curvatures and control uncertainty. The system dynamics include a nonlinear dependence on the curvature, and are coupled with an estimator for the unknown curvature to form the augmented error dynamics. This nonlinear dependence puts our curvature identification objective outside the scope of existing adaptive tracking and parameter identification results that were limited to cases where the unknown parameters …

Extended Poisson Models For Count Data With Inflated Frequencies, Monika Arora

Mathematics & Statistics Theses & Dissertations

Count data often exhibits inflated counts for zero. There are numerous papers in the literature that show how to fit Poisson regression models that account for the zero inflation. However, in many situations the frequencies of zero and of some other value k tends to be higher than the Poisson model can fit appropriately. Recently, Sheth-Chandra (2011), Lin and Tsai (2012) introduced a mixture model to account for the inflated frequencies of zero and k. In this dissertation, we study basic properties of this mixture model and parameter estimation for grouped and ungrouped data. Using stochastic representation we show …

Fiducial Generalized P-Values For Testing Zero-Variance Components In Linear Mixed-Effects Models, Xinmin Li, Haiyan Su, Hua Liang

Department of Applied Mathematics and Statistics Faculty Scholarship and Creative Works

Linear mixed-effects models are widely used in analysis of longitudinal data. However, testing for zero-variance components of random effects has not been well resolved in statistical literature, although some likelihood-based procedures have been proposed and studied. In this article, we propose a generalized p-value based method in coupling with fiducial inference to tackle this problem. The proposed method is also applied to test linearity of the nonparametric functions in additive models. We provide theoretical justifications and develop an implementation algorithm for the proposed method. We evaluate its finite-sample performance and compare it with that of the restricted likelihood ratio test …

Lower Order Perturbations Of Critical Fractional Laplacian Equations, Khalid Fanoukh Al Oweidi

Theses and Dissertations

We give sufficient conditions for the existence of nontrivial solutions to a class of critical nonlocal problems of the Brezis-Nirenberg type. Our result extends some results in the literature for the local case to the nonlocal setting. It also complements the known results for the nonlocal case.

Non-Local Methods In Fracture Dynamics, Eyad Said

LSU Doctoral Dissertations

We first introduce a regularized model for free fracture propagation based on non-local potentials. We work within the small deformation setting and the model is developed within a state based peridynamic formulation. At each instant of the evolution we identify the softening zone where strains lie above the strength of the material. We show that deformation discontinuities associated with flaws larger than the length scale of non-locality $\delta$ can become unstable and grow. An explicit inequality is found that shows that the volume of the softening zone goes to zero linearly with the length scale of non-local interaction. This scaling …

Optimization Studies And Applications: In Retail Gasoline Market, Daero Kim

Electronic Thesis and Dissertation Repository

The study of the retail gasoline market is of great interest in financial economics, since it allows many theories about price formation, oligopolistic markets, and consumer search to be tested. In addition, the risk management of gasoline prices is an important instance of the management of any consumable commodity cost. For the retailer, the tool of dynamic pricing may be found to be useful.

This thesis contributes to the study of retail gasoline markets in three main ways, each in its own paper. The first paper tests various economic models to confirm earlier results about pricing behavior in retail gasoline …

Masked Instability: Within-Sector Financial Risk In The Presence Of Wealth Inequality, Youngna Choi

Department of Applied Mathematics and Statistics Faculty Scholarship and Creative Works

We investigate masked financial instability caused by wealth inequality. When an economic sector is decomposed into two subsectors that possess a severe wealth inequality, the sector in entirety can look financially stable while the two subsectors possess extreme financially instabilities of opposite nature, one from excessive equity, the other from lack thereof. The unstable subsector can result in further financial distress and even trigger a financial crisis. The market instability indicator, an early warning system derived from dynamical systems applied to agent-based models, is used to analyze the subsectoral financial instabilities. Detailed mathematical analysis is provided to explain what financial …

Building Long-Term Support For Faculty Through Graduate Student Instructor Professional Development, Nathan Wakefield, Karina Uhing, Mitchell Hamidi

Department of Mathematics: Faculty Publications

Improving university-level instruction is an important step to improving instruction at all levels, and in order to improve university-level instruction, instructors need to master more effective models of instruction and be able to draw on education literature as they continue to develop as instructors. Well-trained, informed instructors are well equipped to be agents of change when they take on faculty positions. However, this mastery requires training and practice.

Backstepping And Sequential Predictors For Control Systems, Jerome Avery Weston

LSU Doctoral Dissertations

We provide new methods in mathematical control theory for two significant classes of control systems with time delays, based on backstepping and sequential prediction. Our bounded backstepping results ensure global asymptotic stability for partially linear systems with an arbitrarily large number of integrators. We also build sequential predictors for time-varying linear systems with time-varying delays in the control, sampling in the control, and time-varying measurement delays. Our bounded backstepping results are novel because of their use of converging-input-converging-state conditions, which make it possible to solve feedback stabilization problems under input delays and under boundedness conditions on the feedback control. Our …

Spectra Of Quantum Trees And Orthogonal Polynomials, Zhaoxia Wang

LSU Doctoral Dissertations

We investigate the spectrum of regular quantum-graph trees, where the edges are endowed with a Schr\"odinger operator with self-adjoint Robin vertex conditions. It is known that, for large eigenvalues, the Robin spectrum approaches the Neumann spectrum. In this research, we compute the lower Robin spectrum. The spectrum can be obtained from the roots of a sequence of orthogonal polynomials involving two variables. As the length of the quantum tree increases, the spectrum approaches a band-gap structure. We find that the lowest band tends to minus infinity as the Robin parameter increases, whereas the rest of the bands remain positive. Unexpectedly, …

Discrete-Time Hybrid Control In Borel Spaces: Average Cost Optimality Criterion, Héctor Jasso-Fuentes, José-Luis Menaldi, Tomás Prieto-Rumeau, Maurice Robin

Mathematics Faculty Research Publications

This paper addresses an optimal hybrid control problem in discrete-time with Borel state and action spaces. By hybrid we mean that the evolution of the state of the system may undergo deep changes according to structural modifications of the dynamic. Such modifications occur either by the position of the state or by means of the controller's actions. The optimality criterion is of a long-run ratio-average (or ratio-ergodic) type. We provide the existence of optimal average policies for this hybrid control problem by analyzing an associated dynamic programming equation. We also show that this problem can be translated into a standard …

Apotik Jual Obat Aborsi Madiun 081901222272 Agen Obat Cytotec Penggugur Kandungan Di Madiun, Apotik Cytotec

Apotik Cytotec

Transport Phenomena In Field Effect Transistors, Ryan M. Evans, Arvind Balijepalli, Anthony Kearsley

Biology and Medicine Through Mathematics Conference

No abstract provided.

Quantitative Electroencephalography For Detecting Concussions, Sara Krehbiel, Kathy Hoke, Joanna Wares

Biology and Medicine Through Mathematics Conference

No abstract provided.

Finite Element Solution Of The Two-Dimensional Incompressible Navier-Stokes Equations Using Matlab, Endalew G. Tsega, V. K. Katiyar

Applications and Applied Mathematics: An International Journal (AAM)

The Navier–Stokes equations are fundamental in fluid mechanics. The finite element method has become a popular method for the solution of the Navier-Stokes equations. In this paper, the Galerkin finite element method was used to solve the Navier-Stokes equations for two-dimensional steady flow of Newtonian and incompressible fluid with no body forces using MATLAB. The method was applied to the lid-driven cavity problem. The eight-noded rectangular element was used for the formulation of element equations. The velocity components were located at all of 8 nodes and the pressure variable is located at 4 corner of the element. From location of …

Profit Analysis Of A Two Unit Cold Standby System Operating Under Different Weather Conditions Subject T O Inspection, M. S. Barak, Neeraj _, Sudesh Kumari

Applications and Applied Mathematics: An International Journal (AAM)

A system, or unit, is said to be working under normal weather conditions if the system is working under prescribed conditions as defined/stated by the definition of reliability of system/unit, otherwise the system is said to be working in abnormal weather conditions. For example, if a car with the capacity for five persons is carrying more than five persons, it will be said to be working under abnormal weather conditions. Another example, if a hydraulic machine having the capacity to lift a maximum weight of 500 tons is lifting a weight of 600 tons, then the machine is working under …

System Reliability Using Generalized Intuitionistic Fuzzy Rayleigh Lifetime Distribution, Ali Ebrahimnejad, Ezzatallah B. Jamkhaneh

Applications and Applied Mathematics: An International Journal (AAM)

Reliability analysis as one of the important research topics in engineering has been researched by a number of authors. Reliability in classical distributions is based on precise parameters. It is usually assumed that parameters of distributions are precise real numbers. However, in the real world, the data sometimes cannot be measured and recorded precisely. In this paper, the concept of fuzzy reliability is extended by the idea of generalized intuitionistic fuzzy reliability. We investigate the reliability characteristics of systems using Rayleigh lifetime distribution, in which the lifetime parameter is assumed to be generalized intuitionistic fuzzy number. Generalized intuitionistic fuzzy reliability, …

Ultimate Boundedness And Periodicity Results For A Certain System Of Third-Order Nonlinear Vector Delay Differential Equations, Linda D. Oudjedi, Moussadek Remili

Applications and Applied Mathematics: An International Journal (AAM)

In the last years, there has been increasing interest in obtaining the sufficient conditions for stability, instability, boundedness, ultimately boundedness, convergence, etc. For instance, in applied sciences some practical problems concerning mechanics, engineering technique fields, economy, control theory, physical sciences and so on are associated with third, fourth and higher order nonlinear differential equations. The problem of the boundedness and stability of solutions of vector differential equations has been widely studied by many authors, who have provided many techniques especially for delay differential equations. In this work a class of third order nonlinear non-autonomous vector delay differential equations is considered …

Resonance In The Motion Of A Geocentric Satellite Due To Poynting-Robertson Drag, Charanpreet Kaur, Binay K. Sharma, L. P. Pandey

Applications and Applied Mathematics: An International Journal (AAM)

The problem of resonance in a geocentric Satellite under the combined gravitational forces of the Sun and the Earth due to Poynting-Robertson (P-R) drag has been discussed in this paper with the assumption that all three bodies, the Earth, the Sun and the Satellite, lie in an ecliptic plane. Our approach differs from conventional ones as we have placed evaluated velocity of the Satellite in equations of motion.We observed five resonance points commensurable between the mean motion of the Satellite and the average angular velocity of the Earth around the Sun, out of which two resonances occur only due to …

Flow Maximization Problem As Linear Programming Problem With Capacity Constraints, Sushil C. Dimri, Mangey Ram

Applications and Applied Mathematics: An International Journal (AAM)

Flow maximization is a fundamental problem in mathematics; there are several algorithms available to solve this problem, but these algorithms have some limitations. This paper presents the flow maximization problem as a Linear Programming Problem (L.P.P.). The solution given by L.P.P. formulation of the problem and provided by Ford Fulkerson algorithm is same. This paper also compares the single path flow and k-splitting of the flow and suggests that k-splitting of flow is better than single path flow.

Inventory Model With Ramp-Type Demand And Price Discount On Back Order For Deteriorating Items Under Partial Backlogging, Sumit Saha, Nabendu Sen, Biman K. Nath

Applications and Applied Mathematics: An International Journal (AAM)

Modeling of inventory problems provides a good insight to retailers and distributors to maintain stock of different items such as seasonal products, perishable goods and daily useable goods etc. The deterioration of all these items exists to a certain extent due to several reasons like mishandling, evaporation, decay, environmental conditions, transportation etc. It is found from the literature that previously many of the researchers have developed inventory model ignoring deterioration and drawn conclusion. In the absence of deterioration parameter, an inventory model cannot be completely realistic. In this paper, we have made an attempt to extend an inventory model with …

Estimation Of The Burr Xii-Exponential Distribution Parameters, Gholamhossein Yari, Zahra Tondpour

Applications and Applied Mathematics: An International Journal (AAM)

The Burr XII distribution is one of the most important distributions in Survival analysis. In this article, we introduce the new wider Burr XII-G family of distributions. A special model in the new family called Burr XII-exponential distribution that has constant, decreasing and unimodal hazard rate functions is investigated. We discuss the estimation of this distribution parameters by maximum likelihood, three modifications of maximum likelihood and Bayes methods. In Bayes method, we use the uniform, triangular and Burr XII-uniform priors for posterior analysis and obtain Bayes estimations under two different loss functions. We obtain two approximations of the Bayes estimations, …