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- Wavelet Analysis (4)
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- Ricker competition model (2)
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- Allee curve (1)
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- Allee effect (1)
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Articles 1 - 30 of 31
Full-Text Articles in Physical Sciences and Mathematics
The Topology Of Biological Swarms, Lori Ziegelmeier
The Topology Of Biological Swarms, Lori Ziegelmeier
Lori Beth Ziegelmeier
No abstract provided.
On The Data Of Images, Lori Ziegelmeier
An Algorithm In Computational Geometry And An Exploration In Computational Topology, Lori Ziegelmeier
An Algorithm In Computational Geometry And An Exploration In Computational Topology, Lori Ziegelmeier
Lori Beth Ziegelmeier
No abstract provided.
A Behavioural Dynamic Model Of The Relative Age Effect, Kawika Pierson, Vittorio Addona, Phillip Yates
A Behavioural Dynamic Model Of The Relative Age Effect, Kawika Pierson, Vittorio Addona, Phillip Yates
Vittorio Addona
No abstract provided.
Digital Images: They're Not Just For Viewing, Lori Ziegelmeier
Digital Images: They're Not Just For Viewing, Lori Ziegelmeier
Lori Beth Ziegelmeier
No abstract provided.
Variances For Maximum Penalized Likelihood Estimates Obtained Via The Em Algorithm, Mark Segal, Peter Bacchetti, Nicholas Jewell
Variances For Maximum Penalized Likelihood Estimates Obtained Via The Em Algorithm, Mark Segal, Peter Bacchetti, Nicholas Jewell
Mark R Segal
We address the problem of providing variances for parameter estimates obtained under a penalized likelihood formulation through use of the EM algorithm. The proposed solution represents a synthesis of two existent techniques. Firstly, we exploit the supplemented EM algorithm developed in Meng and Rubin (1991) that provides variance estimates for maximum likelihood estimates obtained via the EM algorithm. Their procedure relies on evaluating the Jacobian of the mapping induced by the EM algorithm. Secondly, we utilize a result from Green (1990) that provides an expression for the Jacobian of the mapping induced by the EM algorithm applied to a penalized …
General Allee Effect In Two-Species Population Biology, Saber Elaydi
General Allee Effect In Two-Species Population Biology, Saber Elaydi
Saber Elaydi
The main objective of this work is to present a general framework for the notion of the strong Allee effect in population models, including competition, mutualistic, and predator-prey models. The study is restricted to the strong Allee effect caused by an interspecific interaction. The main feature of the strong Allee effect is that the extinction equilibrium is an attractor. We show how a "phase space core" of three or four equilibria is sufficient to describe the essential dynamics of the interaction between two species that are prone to the Allee effect. We will introduce the notion of semistability in planar …
Bifurcation And Invariant Manifolds Of The Ricker Competition Model, Saber Elaydi
Bifurcation And Invariant Manifolds Of The Ricker Competition Model, Saber Elaydi
Saber Elaydi
We study the stability and bifurcation of all equilibrium points, including extinction, exclusion, and coexistence points. Stable , unsgtable are computed. Moreover, for the nonhyperbolic cases, we computed the center manifolds and determine their stability or lack of it thereof.
Applying A Marginalized Frailty Model To Competing Risks, Stephanie Dixon, G. Darlington, V. Edge
Applying A Marginalized Frailty Model To Competing Risks, Stephanie Dixon, G. Darlington, V. Edge
Stephanie Dixon
No abstract provided.
A Competing Risk Model For Correlated Data Based On The Subdistribution Hazard, Stephanie Dixon, G. Darlington, A. Desmond
A Competing Risk Model For Correlated Data Based On The Subdistribution Hazard, Stephanie Dixon, G. Darlington, A. Desmond
Stephanie Dixon
No abstract provided.
The 1905 Einstein Equation In A General Mathematical Analysis Model Of Quasars, Byron E. Bell
The 1905 Einstein Equation In A General Mathematical Analysis Model Of Quasars, Byron E. Bell
Byron E. Bell
No abstract provided.
Logically Rectangular Finite Volume Methods With Adaptive Refinement On The Sphere, Marsha Berger, Donna Calhoun, Christiane Helzel, Randall Leveque
Logically Rectangular Finite Volume Methods With Adaptive Refinement On The Sphere, Marsha Berger, Donna Calhoun, Christiane Helzel, Randall Leveque
Donna Calhoun
The logically rectangular finite volume grids for two-dimensional partial differential equations on a sphere and for three-dimensional problems in a spherical shell introduced recently have nearly uniform cell size, avoiding severe Courant number restrictions. We present recent results with adaptive mesh refinement using the GEOCLAW software and demonstrate well-balanced methods that exactly maintain equilibrium solutions, such as shallow water equations for an ocean at rest over arbitrary bathymetry.
A Finite Volume Method For Solving Parabolic Equations On Logically Cartesian Curved Surface Meshes, Donna Calhoun, Christiane Helzel
A Finite Volume Method For Solving Parabolic Equations On Logically Cartesian Curved Surface Meshes, Donna Calhoun, Christiane Helzel
Donna Calhoun
We present a second-order, finite-volume scheme for the constant-coefficient diffusion equation on curved, parametric surfaces described via smooth or piecewise smooth mappings on logically Cartesian meshes. Our method does not require analytic metric terms, shows second-order accuracy, can be easily coupled to existing finite-volume solvers for logically Cartesian meshes and handles general mixed boundary conditions. We present numerical results demonstrating the accuracy of the scheme, and then use the scheme to solve advection-reaction-diffusion equations modeling biological pattern formation on surfaces.
Bayesian Density Forecasting Of Intraday Electricity Prices Using Multivariate Skew T Distributions, Anastasios Panagiotelis, Michael Smith
Bayesian Density Forecasting Of Intraday Electricity Prices Using Multivariate Skew T Distributions, Anastasios Panagiotelis, Michael Smith
Michael Stanley Smith
Electricity spot prices exhibit strong time series properties, including substantial periodicity, both inter-day and intraday serial correlation, heavy tails and skewness. In this paper we capture these characteristics using a first order vector autoregressive model with exogenous effects and a skew t distributed disturbance. The vector is longitudinal, in that it comprises observations on the spot price at intervals during a day. A band two inverse scale matrix is employed for the disturbance, as well as a sparse autoregressive coefficient matrix. This corresponds to a parsimonious dependency structure that directly relates an observation to the two immediately prior, and the …
A Mathematical Regression Of The U.S. Gross Private Domestic Investment 1959-2001, Byron E. Bell
A Mathematical Regression Of The U.S. Gross Private Domestic Investment 1959-2001, Byron E. Bell
Byron E. Bell
SUMMARY OF PROJECT What did I do? A study of the role the U.S. stock markets and money markets have possibly played in the Gross Private Domestic Investment (GPDI) of the United States from the year 1959 to the year 2001 and I created a Multiple Linear Regression Model (MLRM).
An Euler-Type Formula For Zeta (2k+1), Tian-Xiao He
An Euler-Type Formula For Zeta (2k+1), Tian-Xiao He
Tian-Xiao He
No abstract provided.
If F(X) =∫X2x F(T) Dt Is Constant, Must F(T) = C/T ?, Tian-Xiao He
If F(X) =∫X2x F(T) Dt Is Constant, Must F(T) = C/T ?, Tian-Xiao He
Tian-Xiao He
No abstract provided.
Mra Frame Wavelets With Certain Regularities Associated With The Refinable Generators Of Shift Invariant Spaces, Tian-Xiao He
Mra Frame Wavelets With Certain Regularities Associated With The Refinable Generators Of Shift Invariant Spaces, Tian-Xiao He
Tian-Xiao He
In this paper, we will start the discussion with the refinable generators of the shift invariant (SI) spaces in L2 (R) that possess the largest possible regularities and required vanishing moments. For the pseudo-scaling generators, the corresponding MRA frame wavelets with certain regularities are constructed. In addition, the stability of the refinable SI spaces and the corresponding complementary spaces, biorthogonality of the SI spaces, and the approximation property of the spaces are also discussed.
Biorthogonal Spline Type Wavelets, Tian-Xiao He
Biorthogonal Spline Type Wavelets, Tian-Xiao He
Tian-Xiao He
Let ¢ be an orthonormal scaling function with approximation degree p - 1, and let Bn be the B-spline of order n. Then, spline type scaling functions defined by fn = f * Bn (n = 1, 2, ... ) possess higher approximation order, p+n-1, and compact support. The corresponding biorthogonal wavelet functions are also constructed. This technique is extended to the case of biorthogonal scaling function system. As an application of the method supplied in this paper, one can easily construct a sequence of pairs of biorthogonal spline type scaling functions from one pair of biorthogonal scaling functions or …
Boundary-Type Quadrature And Boundary Element Method, Tian-Xiao He
Boundary-Type Quadrature And Boundary Element Method, Tian-Xiao He
Tian-Xiao He
In this paper, we apply a boundary-type quadrature technique to derive a type of boundary element scheme, which is used to solve the boundary-value problems of partial differential equations.Numerical examples for solving the exterior boundary-value problem of Helmholtz equation by using the spline approximation and the spline wavelet approximation are given.
Stable Refinable Generators Of Shift Invariant Spaces With Certain Regularities And Vanishing Moments, Tian-Xiao He
Stable Refinable Generators Of Shift Invariant Spaces With Certain Regularities And Vanishing Moments, Tian-Xiao He
Tian-Xiao He
In this paper, we discuss the stable refinable functions that generate shift in variant (SI) spaces and possess the largest possible regularities and required vanishing moments. The stability of the corresponding complementary spaces is also discussed.
Biorthogonal Wavelets With Certain Regularities, Tian-Xiao He
Biorthogonal Wavelets With Certain Regularities, Tian-Xiao He
Tian-Xiao He
In this paper, we will discuss the construction of biorthogonal wavelets that possess the largest possible regularities and required vanishing moments. For the sake of applications, we also give a general Daubechies’ iteration method of constructing biorthogonal wavelets by using biorthogonal splines.
Biorthogonal Wavelets With Certain Regularities, Tian-Xiao He
Biorthogonal Wavelets With Certain Regularities, Tian-Xiao He
Tian-Xiao He
No abstract provided.
Biorthogonal Wavelets With Certain Regularities, Tian-Xiao He
Biorthogonal Wavelets With Certain Regularities, Tian-Xiao He
Tian-Xiao He
No abstract provided.
Boundary Quadrature Formulas And Their Applications, Tian-Xiao He
Boundary Quadrature Formulas And Their Applications, Tian-Xiao He
Tian-Xiao He
This chapter surveys the analytical approach for constructing multivariate numerical integration formulas that use only boundary points as evaluation points. The applications of boundary quadrature formulas to boundary value problems of partial differential equations are also discussed.
C1 Quadratic Macroelements And C1 Orthogonal Multiresolution Analyses In 2d, Tian-Xiao He
C1 Quadratic Macroelements And C1 Orthogonal Multiresolution Analyses In 2d, Tian-Xiao He
Tian-Xiao He
Each triangle of an arbitrary regular triangulation Δ of a polygonal region in R2 is subdivided into twelve subtriangles by using three connecting lines joining three arbitrarily chosen points on its edges, three connecting lines from an arbitrarily chosen interior point in the triangle to its three vertices, and three connecting lines joining the points on the edges and the interior point. In this refinement, C1 quadratic finite elements can be constructed. In this paper, we will give explicit Bezier coefficients of elements in terms of the parameters that describe function and first partial derivative values at vertices …
Short Time Fourier Transform, Integral Wavelet Transform, And Wavelet Functions Associated With Splines, Tian-Xiao He
Short Time Fourier Transform, Integral Wavelet Transform, And Wavelet Functions Associated With Splines, Tian-Xiao He
Tian-Xiao He
In this article, we discuss short time Fourier transforms, integral wavelet transforms, and wavelet series expansions associated with spline functions in shift-invariant spaces of B-splines. A recurrence relation formula and the corresponding algorithm about the B-wavelets are also given.
Shape Criteria Of Bernstein-Bezier Polynomials Over Simplexes, Tian-Xiao He
Shape Criteria Of Bernstein-Bezier Polynomials Over Simplexes, Tian-Xiao He
Tian-Xiao He
This paper discusses the criteria of convexity, monotonicity, and positivity of Bernstein- Bezier polynomials over simplexes.
On A General Class Of Multivariate Linear Smoothing Operators, Tian-Xiao He
On A General Class Of Multivariate Linear Smoothing Operators, Tian-Xiao He
Tian-Xiao He
No abstract provided.
Asymptotic Properties Of Positive Summation-Integral Operators, Tian-Xiao He
Asymptotic Properties Of Positive Summation-Integral Operators, Tian-Xiao He
Tian-Xiao He
No abstract provided.