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Articles 4651 - 4680 of 7935

Full-Text Articles in Applied Mathematics

Pulses And Snakes In Ginzburg-Landau Equation, S.C. Mancas, Roy S. Choudhury Jan 2015

Pulses And Snakes In Ginzburg-Landau Equation, S.C. Mancas, Roy S. Choudhury

Publications

Using a variational formulation for partial differential equations combined with numerical simulations on ordinary differential equations (ODEs), we find two categories (pulses and snakes) of dissipative solitons, and analyze the dependence of both their shape and stability on the physical parameters of the cubic-quintic Ginzburg–Landau equation (CGLE). In contrast to the regular solitary waves investigated in numerous integrable and non-integrable systems over the last three decades, these dissipative solitons are not stationary in time. Rather, they are spatially confined pulse-type structures whose envelopes exhibit complicated temporal dynamics. Numerical simulations reveal very interesting bifurcations sequences as the parameters of the CGLE …

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Stability Of A Circular System With Multiple Asymmetric Laplacians, Ivo Herman, Dan Martinec, J. J. P. Veerman, Michael Sebek Jan 2015

Stability Of A Circular System With Multiple Asymmetric Laplacians, Ivo Herman, Dan Martinec, J. J. P. Veerman, Michael Sebek

Mathematics and Statistics Faculty Publications and Presentations

We consider an asymptotic stability of a circular system where the coupling Laplacians are different for each state used for synchronization. It is shown that there must be a symmetric coupling in the output state to guarantee the stability for agents with two integrators in the open loop. Systems with agents having three or more integrators cannot be stabilized by any coupling. In addition, recent works in analysis of a scaling in vehicular platoons relate the asymptotic stability of a circular system to a string stability. Therefore, as confirmed by simulations in the paper, our results have an application also …

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Blurring And Deblurring Digital Images Using The Dihedral Group, Husein Hadi Abbas Jassim, Zahir M. Hussain, Hind R.M. Shaaban, Kawther B.R. Al-Dbag Jan 2015

Blurring And Deblurring Digital Images Using The Dihedral Group, Husein Hadi Abbas Jassim, Zahir M. Hussain, Hind R.M. Shaaban, Kawther B.R. Al-Dbag

Research outputs 2014 to 2021

A new method of blurring and deblurring digital images is presented. The approach is based on using new filters generating from average filter and H-filters using the action of the dihedral group. These filters are called HB-filters; used to cause a motion blur and then deblurring affected images. Also, enhancing images using HB-filters is presented as compared to other methods like Average, Gaussian, and Motion. Results and analysis show that the HB-filters are better in peak signal to noise ratio (PSNR) and RMSE.

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Evaluating The Long-Term Effects Of Logging Residue Removals In Great Lakes Aspen Forests, Michael I. Premer Jan 2015

Evaluating The Long-Term Effects Of Logging Residue Removals In Great Lakes Aspen Forests, Michael I. Premer

Dissertations, Master's Theses and Master's Reports

Commercial aspen (Populus spp.) forests of the Great Lakes region are primarily managed for timber products such as pulp fiber and panel board, but logging residues (topwood and non-merchantable bolewood) are potentially important for utilization in the bioenergy market. In some regions, pulp and paper mills already utilize residues as fuel in combustion for heat and electricity, and progressive energy policies will likely cause an increase in biomass feedstock demand. The effects of removing residues, which have a comparatively high concentration of macronutrients, is poorly understood when evaluating long-term site productivity, future timber yields, plant diversity, stand dynamics, and …

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A Class Of High-Order Runge-Kutta-Chebyshev Stability Polynomials, Stephen O'Sullivan Jan 2015

A Class Of High-Order Runge-Kutta-Chebyshev Stability Polynomials, Stephen O'Sullivan

Articles

The analytic form of a new class of factorized Runge-Kutta-Chebyshev (FRKC) stability polynomials of arbitrary order N is presented. Roots of FRKC stability polynomials of degree L = MN are used to construct explicit schemes comprising L forward Euler stages with internal stability ensured through a sequencing algorithm which limits the internal amplification factors to ~ L2. The associated stability domain scales as M2 along the real axis. Marginally stable real-valued points on the interior of the stability domain are removed via a prescribed damping procedure. By construction, FRKC schemes meet all linear order conditions; for nonlinear …

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A Hamiltonian Approach To Wave-Current Interactions In Two-Layer Fluids, Adrian Constantin, Rossen Ivanov Jan 2015

A Hamiltonian Approach To Wave-Current Interactions In Two-Layer Fluids, Adrian Constantin, Rossen Ivanov

Articles

We provide a Hamiltonian formulation for the governing equations describing the two-dimensional nonlinear interaction between coupled surfacewaves, internalwaves, and an underlying current with piecewise constant vorticity, in a two-layered fluid overlying a flat bed. This Hamiltonian structure is a starting point for the derivation of simpler models, which can be obtained systematically by expanding the Hamiltonian in dimensionless parameters. These enable an in-depth study of the coupling between the surface and internal waves, and how both these wave systems interact with the background current.

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On The Dynamics Of Internal Waves Interacting With The Equatorial Undercurrent, Alan Compelli, Rossen Ivanov Jan 2015

On The Dynamics Of Internal Waves Interacting With The Equatorial Undercurrent, Alan Compelli, Rossen Ivanov

Articles

The interaction of the nonlinear internal waves with a nonuniform current with a specific form, characteristic for the equatorial undercurrent, is studied. The current has no vorticity in the layer, where the internal wave motion takes place. We show that the nonzero vorticity that might be occuring in other layers of the current does not affect the wave motion. The equations of motion are formulated as a Hamiltonian system.

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Will Oscillating Wave Surge Converters Survive Tsunamis?, Laura Cooke, P. Christodoulides, E. Renzi, T. Stefanakis, F. Dias Jan 2015

Will Oscillating Wave Surge Converters Survive Tsunamis?, Laura Cooke, P. Christodoulides, E. Renzi, T. Stefanakis, F. Dias

Articles

With an increasing emphasis on renewable energy resources, wave power technology is becoming one of the realistic solutions. However, the 2011 tsunami in Japan was a harsh reminder of the ferocity of the ocean. It is known that tsunamis are nearly undetectable in the open ocean but as the wave approaches the shore its energy is compressed, creating large destructive waves. The question posed here is whether an oscillating wave surge converter (OWSC) could withstand the force of an incoming tsunami. Several tools are used to provide an answer: an analytical 3D model developed within the framework of linear theory, …

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Shape Optimization For Drag Minimization Using The Navier-Stokes Equation, Chukwudi Paul Chukwudozie Jan 2015

Shape Optimization For Drag Minimization Using The Navier-Stokes Equation, Chukwudi Paul Chukwudozie

LSU Master's Theses

Fluid drag is a force that opposes relative motion between fluid layers or between solids and surrounding fluids. For a stationary solid in a moving fluid, it is the amount of force necessary to keep the object stationary in the moving fluid. In addition to fluid and flow conditions, pressure drag on a solid object is dependent on the size and shape of the object. The aim of this project is to compute the shape of a stationary 2D object of size 3.5 m2 that minimizes drag for different Reynolds numbers. We solve the problem in the context of shape …

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Analysis Of Nonlinear Dispersive Model Equations, Jacob Grey Jan 2015

Analysis Of Nonlinear Dispersive Model Equations, Jacob Grey

LSU Doctoral Dissertations

In this work we begin with a brief survey of the classical fluid dynamics problem of water waves, and then proceed to derive well known evolution equations via a Hamiltonian Variational approach. This method was first introduced in the seminal work of Walter Craig, et al. \cite{CG}. The distinguishing feature of this scheme is that the Dirichlet-Neumann operator of the fluid domain appears explicitly in the Hamiltonian. In the second and third chapters, we utilize the Hamiltonian perturbation theory introduced in \cite{CG} to derive the Benjamin-Bona-Mahony (BBM) and Benjamin-Bona-Mahony-Kadomtsev-Petviashvili (BBM-KP)equations. Finally, we briefly review the existence theory for their corresponding …

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Topological Dynamics On Compact Phase Spaces, Lieth Abdalateef Majed Jan 2015

Topological Dynamics On Compact Phase Spaces, Lieth Abdalateef Majed

LSU Doctoral Dissertations

Our main focus will be to investigate the various facets of what are commonly called dynamical systems or flows, which are triples $(S,X,\pi)$, where $X$ is a compact Hausdorff space and $\pi:S \times X \longrightarrow X$ is a separately continuous action of a semigroup $S$ on $X$. Historically, as was introduced by R.Ellis 1960, the enveloping semigroup, which is a closure of the set of continuous functions on a compact space $X$, was discovered to be an important tool to study dynamical systems. Soon, a realization of the existence of a universal compactification of a phase semigroup with an extended …

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A New Method In Distribution Theory With A Non-Smooth Framework, Yunyun Yang Jan 2015

A New Method In Distribution Theory With A Non-Smooth Framework, Yunyun Yang

LSU Doctoral Dissertations

In this work, we present a complete treatment of the theory of thick distributions and its asymptotic expansion. We also present several applications of thick distributions in mathematical physics, function spaces, and measure theory. We also discuss regularization using different surfaces. In the last chapter we present some recent applications of distributions in clarifying the moment terms in the heat kernel expansion, and in explaining the relation between the heat kernel expansion and the cylinder kernel expansion.

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Exploring Rational Numbers In Middle School, Robyn Jasmin Boudoin Jan 2015

Exploring Rational Numbers In Middle School, Robyn Jasmin Boudoin

LSU Master's Theses

The move by the state of Louisiana to fully implement the Common Core State Standards (CCSS) from 2013 -2014 school year on and to align all state mandated tests to the CCSS has caused teachers to change the way they teach and how they deliver content. The overall most crucial new part of the CCSS in Mathematics is the emphasis on the “Standards for Mathematical Practice”. In order to illustrate the meaning of the Mathematical Practice Standards, non routine problems must be used that allow students and teachers to “dig deeper” and practice their mathematical habits of mind. Rational numbers …

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Improved Full-Newton-Step Infeasible Interior-Point Method For Linear Complementarity Problems, Mustafa Ozen Jan 2015

Improved Full-Newton-Step Infeasible Interior-Point Method For Linear Complementarity Problems, Mustafa Ozen

College of Graduate Studies: Theses & Dissertations

In this thesis, we present an improved version of Infeasible Interior-Point Method (IIPM) for monotone Linear Complementarity Problem (LCP). One of the most important advantages of this version in compare to old version is that it only requires feasibility steps. In the earlier version, each iteration consisted of one feasibility step and some centering steps (at most three in practice). The improved version guarantees that after one feasibility step, the new iterated point is feasible and close enough to central path. Thus, the centering steps are eliminated. This improvement is based on the Lemma(Roos, 2015). Thanks to this lemma, proximity …

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Enumerating Graphs Using Integrals From Quantum Field Theory, William A. Coggins Jan 2015

Enumerating Graphs Using Integrals From Quantum Field Theory, William A. Coggins

College of Graduate Studies: Theses & Dissertations

Enumerating graphs is a relatively new subfield of mathematics. In this thesis, we will discuss a enumerative method that derives from Quantum Field Theory. We begin with the basic ideas of Calculus and extend them into a enumerative method that will allow us to classify graphs embedded on surfaces.

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Wavelets, Coorbit Theory, And Projective Representations, Amer Hasan Darweesh Jan 2015

Wavelets, Coorbit Theory, And Projective Representations, Amer Hasan Darweesh

LSU Doctoral Dissertations

Banach spaces of functions, or more generally, of distributions are one of the main topics in analysis. In this thesis, we present an abstract framework for construction of invariant Banach function spaces from projective group representations. Coorbit theory gives a unified method to construct invariant Banach function spaces via representations of Lie groups. This theory was introduced by \Fch\, and \Gro\, in \cite{FG,FG1, FG2,FG3} and then extended in \cite{CO2}. We generalize this concept by constructing coorbit spaces using projective representation which is first studied by O. Christensen in \cite{O1}. This allows us to describe wider classes of function spaces as …

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Loss Modeling Of A Permanent Magnet Dc Motor Drive Water Pumping System, Nelson Lujara Dec 2014

Loss Modeling Of A Permanent Magnet Dc Motor Drive Water Pumping System, Nelson Lujara

Tanzania Journal of Engineering and Technology (TJET)

The paper presents an analytical approach to the determination of losses in each of the sub-systems of the Photovoltaic (PV) Permanent Magnet DC Motor (PMDC) drive water pumping system with and without maximum power tracking. The losses of the system at varying heads are firstly, determined using parameters from the data sheets and then validated by experimental results. The results are used to establish the head and the flow rate optimal operating point of the system.

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Application Of Trip Generation Models For Urban Transport Planning In A Data Scarce Developing Country City: The Case Of Dar Es Salaam, Hannibal Bwire Dec 2014

Application Of Trip Generation Models For Urban Transport Planning In A Data Scarce Developing Country City: The Case Of Dar Es Salaam, Hannibal Bwire

Tanzania Journal of Engineering and Technology (TJET)

With the increase in travel demand and traffic management problems in many developing countries cities, travel demand forecasting models are being employed increasingly to make informed decisions about the operational improvements to the existing transportation system and the design and performance of future transportation systems. The main advantage of using travel demand forecasting models for such purposes is that they are capable of capturing the interactive effects of different components of the system under study. However, for some time now there have been concerns about the application of transport planning models in developing countries. The concerns have been mainly in …

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Rainich-Type Conditions For Perfect Fluid Spacetimes, Dionisios Krongos, Charles G. Torre Dec 2014

Rainich-Type Conditions For Perfect Fluid Spacetimes, Dionisios Krongos, Charles G. Torre

Research Vignettes

In this worksheet we describe and illustrate a relatively simple set of new Rainich-type conditions on an n-dimensional spacetime which are necessary and sufficient for it to define a perfect fluid solution of the Einstein field equations. Procedures are provided which implement these Rainich-type conditions and which reconstruct the perfect fluid from the metric. These results provide an example of the idea of geometrization of matter fields in general relativity, which is a purely geometrical characterization of matter fields via the Einstein field equations.

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Integrating Path-Dependent Functionals On Yeh-Wiener Space, Ian Pierce, David Skough Dec 2014

Integrating Path-Dependent Functionals On Yeh-Wiener Space, Ian Pierce, David Skough

Department of Mathematics: Faculty Publications

Denote by Ca,b(Q) the generalized two-parameter Yeh-Wiener space with associated Gaussian measure. We investigate several scenarios in which integrals of functionals on this space can be reduced to integrals of related functionals over an appropriate single-parameter generalized Wiener space Cˆa,ˆb[0, T ]. This extends some interesting results of R. H. Cameron and D. A. Storvick.

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A Periodic Matrix Population Model For Monarch Butterflies, Emily Hunt Dec 2014

A Periodic Matrix Population Model For Monarch Butterflies, Emily Hunt

Senior Honors Projects, 2010-2019

The migration pattern of the monarch butterfly (Danaus plexippus) consists of a sequence of generations of butterflies that originate in Michoacan, Mexico each spring, travel as far north as Southern Canada, and ultimately return to the original location in Mexico the following fall. We use periodic population matrices to model the life cycle of the eastern monarch butterfly and find that, under this model, this migration is not currently at risk. We extend the model to address the three primary obstacles for the long-term survival of this migratory pattern: deforestation in Mexico, increased extreme weather patterns, and milkweed degradation.

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On A Nonlinear Hyperbolic Partial Differential Equation With Irregular Data, Victor D´Evou´E Dec 2014

On A Nonlinear Hyperbolic Partial Differential Equation With Irregular Data, Victor D´Evou´E

Applications and Applied Mathematics: An International Journal (AAM)

The main purpose of this paper is to study the existence and properties of solutions of a certain nonlinear non-Lipschitz hyperbolic partial differential equation in two independent variables with irregular data. Using regularization techniques, we give a meaning to this problem by replacing it by a tow parameters family of Lipschitz regular problems. We prove existence and uniqueness of the solution in an appropriate algebra of generalized functions and we precise how it depends on the choices made. We study the relationship with the classical solution.

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Long Wavelength Analysis Of A Model For The Geographic Spread Of A Disease, Layachi Hadji Dec 2014

Long Wavelength Analysis Of A Model For The Geographic Spread Of A Disease, Layachi Hadji

Applications and Applied Mathematics: An International Journal (AAM)

We investigate the temporal and spatial evolution of the spread of an infectious disease by performing a long-wavelength analysis of a classical model for the geographic spread of a rabies epidemic in a population of foxes subject to idealized boundary conditions. We consider twodimensional and three-dimensional landscapes consisting of an infinite horizontal strip bounded by two walls a finite distance apart and a horizontal region bounded above and below by horizontal walls, respectively. A nonlinear partial differential evolution Equation for the leading order of infectives is derived. The Equation captures the space and time variations of the spread of the …

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Applying Gmdh-Type Neural Network And Particle Warm Optimization For Prediction Of Liquefaction Induced Lateral Displacements, Reza A. Jirdehi, Hamidreza T. Mamoudan, Hossein H. Sarkaleh Dec 2014

Applying Gmdh-Type Neural Network And Particle Warm Optimization For Prediction Of Liquefaction Induced Lateral Displacements, Reza A. Jirdehi, Hamidreza T. Mamoudan, Hossein H. Sarkaleh

Applications and Applied Mathematics: An International Journal (AAM)

Lateral spreading and flow failure are amongst the most destructive effects of liquefaction. Estimation of the peril of lateral spreading requires characterization of subsurface conditions, principally soil density, fine content, groundwater conditions, site topography and seismic characteristics. In this paper a GMDH-type neural network and particle swarm optimization is developed for prediction of liquefaction induced lateral displacements. Using this method, a new model was proposed that is suitable for predicting the liquefaction induced lateral displacements. The proposed model was tested before the requested calculation. The data set which is contains 250 data points of liquefaction-induced lateral ground spreading case histories …

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A Semiparametric Estimation For Regression Functions In The Partially Linear Autoregressive Time Series Model, R. Farnoosh, M. Hajebi, S. J. Mortazavi Dec 2014

A Semiparametric Estimation For Regression Functions In The Partially Linear Autoregressive Time Series Model, R. Farnoosh, M. Hajebi, S. J. Mortazavi

Applications and Applied Mathematics: An International Journal (AAM)

In this paper, a semiparametric method is proposed for estimating regression function in the partially linear autoregressive time series model . Here, we consider a combination of parametric forms and nonlinear functions, in which the errors are independent. Semiparametric and nonparametric curve estimation provides a useful tool for exploring and understanding the structure of a nonlinear time series data set to make for a more efficient study in the partially linear autoregressive model. The unknown parameters are estimated using the conditional nonlinear least squares method, and the nonparametric adjustment is also estimated by defining and minimizing the local L2 -fitting …

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Existence Of Mild Solutions For Semilinear Impulsive Functional Mixed Integro-Differential Equations With Nonlocal Conditions, Kamalendra Kumar, Rakesh Kumar Dec 2014

Existence Of Mild Solutions For Semilinear Impulsive Functional Mixed Integro-Differential Equations With Nonlocal Conditions, Kamalendra Kumar, Rakesh Kumar

Applications and Applied Mathematics: An International Journal (AAM)

In this paper, we prove the existence, uniqueness and continuous dependence of initial data on mild solutions of first order semilinear functional impulsive mixed integro-differential equations with nonlocal condition in general Banach spaces. The results are obtained by using the semigroup theory and Banach contraction theorem.

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Modern Approach For Designing And Solving Interval Estimated Linear Fractional Programming Models, S. Ananthalakshmi, C. Vijayalakshmi, V. Ganesan Dec 2014

Modern Approach For Designing And Solving Interval Estimated Linear Fractional Programming Models, S. Ananthalakshmi, C. Vijayalakshmi, V. Ganesan

Applications and Applied Mathematics: An International Journal (AAM)

Optimization methods have been widely applied in statistics. In mathematical programming, the coefficients of the models are always categorized as deterministic values. However uncertainty always exists in realistic problems. Therefore, interval-estimated optimization models may provide an alternative choice for considering the uncertainty into the optimization models. In this aspect, this paper concentrates, the lower and upper values of interval estimated linear fractional programming model (IELFPM) are obtained by using generalized confidence interval estimation method. An IELFPM is a LFP with interval form of the coefficients in the objective function and all requirements. The solution of the IELFPM is also analyzed.

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Modelling The Dynamics Of A Renewable Resource Under Harvesting With Taxation As A Control Variable, B. Dubey, Atasi Patra, S. K. Sahani Dec 2014

Modelling The Dynamics Of A Renewable Resource Under Harvesting With Taxation As A Control Variable, B. Dubey, Atasi Patra, S. K. Sahani

Applications and Applied Mathematics: An International Journal (AAM)

The present paper describes a model of resource biomass and population with a non-linear catch rate function on resource biomass. The harvesting effort is assumed to be a dynamical variable. Tax on per unit harvested resource biomass is used as a tool to control exploitation of the resource. Pontryagin’s Maximum Principle is used to find the optimal control to maintain the resource biomass and population at an optimal level. A numerical simulation is also carried out to support the analytical results.

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Among Several Successful Algorithms, Simpler Ones Usually Work Better: A Possible Explanation Of An Empirical Observation, Vladik Kreinovich, Olga Kosheleva Dec 2014

Among Several Successful Algorithms, Simpler Ones Usually Work Better: A Possible Explanation Of An Empirical Observation, Vladik Kreinovich, Olga Kosheleva

Departmental Technical Reports (CS)

Often, several different algorithms can solve a certain practical problem. Sometimes, algorithms which are successful in solving one problem can solve other problems as well. How can we decide which of the original algorithms is the most promising -- i.e., which is more probable to be able to solve other problem? In many cases, the simplest algorithms turns out to be the most successful. In this paper, we provide a possible explanation for this empirical observation.

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Scaling Group Analysis On Mhd Free Convective Heat And Mass Transfer Over A Stretching Surface With Suction / Injection, Heat Source/Sink Considering Viscous Dissipation And Chemical Reaction Effects, Hunegnaw Dessie, Naikoti Kishan Dec 2014

Scaling Group Analysis On Mhd Free Convective Heat And Mass Transfer Over A Stretching Surface With Suction / Injection, Heat Source/Sink Considering Viscous Dissipation And Chemical Reaction Effects, Hunegnaw Dessie, Naikoti Kishan

Applications and Applied Mathematics: An International Journal (AAM)

This paper concerns with scaling group analysis on MHD free convective heat and mass transfer over stretching surface considering effects of thermal-diffusion and diffusion-thermo with suction /injection, heat source/sink and chemical reaction by taking into account viscous dissipation. Scaling group transformations are used to convert the partial differential equations of governing equations into ordinary differential equation and are solved numerically by Keller Box Method. Numerical results obtained for different parameters are drawn graphically and their effects on velocity, temperature and concentration profiles are discussed and shown graphically. Skin-friction coefficient, Nusselt number and Sherwood number are presented in table. It is …

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