bluuebunny/crossref_metadata_2025_split huggingface dataset:
Variational and Finite Element Analysis of Vibroequilibria
Authors: Beyer K. , Günther M. , Timokha K. 
Published: April 2013

AbstractWe adapt, via asymptotic expansion, Kapitsa's formula for the effective
potential of a pendulum with vibrating suspension to rapidly forced potential flows with
free boundaries. Determination of time-averaged stationary states leads to an optimal
shape design problem. Under periodic boundary conditions existence and uniqueness of
smooth minimizers to the averaged energy is proved using local coerciveness. In the numerical
part of the article, 2D and 3D finite element approximations including related
error estimates are discussed. Some illustrating examples are sketched.
Spectral Collocation and Waveform Relaxation Methods with Gegenbauer Geconstruction for Nonlinear Conservation Laws
Authors: Jackiewicz Z. , Zubik-Kowal B. 
Published: April 2013

Abstract We investigate the Chebyshev spectral collocation and waveform relaxation methods for nonlinear conservation laws. Waveform relaxation methods allow
to replace the system of nonlinear differential equations resulting from the application
of spectral collocation methods by a sequence of linear problems which can be effectively integrated by highly stable implicit methods. The obtained numerical solution is
then enhanced on the intervals of smoothness by the Gegenbauer reconstruction. The
effectiveness of this approach is illustrated by numerical experiments.
Transfer Matrix Study of Finite-size Corrections in the 2D Ising Model
Authors: Kaupužs J. 
Published: April 2013

AbstractEffective exact transfer matrix algorithms have been developed to compute the two-point correlation function G(r) of the 2D Ising model on a square finite size lattice. Systems including up to 800 spins have been considered and corrections to the finite-size scaling at the critical point have been analysed.As a new result, we
have found that the correlation function has a nontrivial amplitude correction of a very small magnitude.
Functional-discrete Method for Eigenvalue Transmission Problem with Periodic Boundary Conditions
Authors: Makarov V. L. , Rossokhata N. O. , Bandyrsiĭ B. Ĭ. 
Published: April 2013

AbstractWe apply a functional-discrete method with convergence rate not worse than that of a geometric series for an eigenvalue transmission problem with periodic boundary conditions. It is shown that the convergence rate increases with an increase in the ordinal number of trial eigenvalue. Based on asymptotic behavior of eigenvalues of the basic problem and the functional-discrete method, qualitative results concerning the arrangement of the eigenvalues of the original eigenvalue transmission problem with periodic boundary conditions are proved. A number of numerical examples are given to support the theory.
A New Fast Iterative Method for Interpolation of Multivariate Scattered Data
Authors: Masjukov Andrey V. , Masjukov Vladimir I. 
Published: April 2013

AbstractThis paper presents Iterative Scalable Smoothing (ISS), a new itera-
tive multi-scale method for multivariate interpolation of scattered data. Each iteration
step in the process reduces the residues of the current interpolation result by appli-
cation of a smoothing operator to a piecewise constant function that interpolates the
residues of the current interpolant, and by adding the resulting function to the current
approximation, which is initially set to zero. The convergence of the method is proved
and conditions for the di®erentiability of the convergence result are given. For a uni-
form mesh an e±cient algorithm is constructed, for which the numerical complexity is
estimated.
Several 2D numerical examples illustrate the theoretical results. By a 3D test with
several test-functions and random nodes it is shown that the accuracy of the proposed
method is comparable with the quadratic modiffcation of Shepard's method, which
is known to be more accurate than triangle-based methods. Then, in 1D tests, by
stochastic simulation with random nodes and random functions the ISS method is
compared with the Cubic Splines method, Shepard's method and the Kriging method.
We also compare the stability of these methods with respect to noisy data. For the
special case of regular nodes, properties of the method are verified by comparing its
1D response function with the response function of the cubic spline and the perfect
interpolator (the sinc-function).
Special attention is paid to the e®ect of the tuning parameter
Automatic Computation of Conservation Laws in the Calculus of Variations and Optimal Control
Authors: Gouvei Paulo D. F. , Torres Delfim F. M. 
Published: April 2013

AbstractWe present analytical computational tools that permit us to identify, in an automatic way, conservation laws in optimal control. The central result we use is the famous Noether's theorem, a classical theory developed by Emmy Noether in 1918, in the context of the calculus of variations and mathematical physics, which was extended recently to the more general context of optimal control. We show how a Computer Algebra System can be very helpful in finding the symmetries and corresponding conservation laws in optimal control theory, thus making useful in practice the theoretical results recently obtained in the literature. A Maple implementation is provided and several illustrative examples are given.
Improved Applications of Relaxation Schemes for Hyperbolic Systems of Conservation Laws and Convection-diffusion Problems
Authors: Seaïd Mohammed 
Published: April 2013

AbstractA class of third-order relaxation schemes for hyperbolic systems of
conservation laws with source terms is reconstructed. The schemes employ general
higher-order reconstruction for spatial discretization and higher-order implicit-explicit
schemes or TVD Runge — Kutta schemes for time integration of relaxed systems. Extension
to multidimensional convection-diffusion problems is also included in this paper.
Numerical results for inviscid gas Euler equations, shallow water and incompressible
Navier — Stokes equations are given in both one and two space dimensions.
Sharp Error Bounds for a Symmetrized Locally 1d Method for Solving the 2d Heat Equation
Authors: Zlotnik Alexander , Ilyicheva Svetlana 
Published: April 2013

Abstract We analyze the three-stage symmetrized locally 1D finite-difference
scheme for solving an initial-boundary value problem for the 2D heat equation. Error
bounds of orders and related ones are proved for nonsmooth data. The sharpness in order
of these in a strong sense is confirmed by
deriving the corresponding lower error bounds. The error bounds are, in the main,
worse than the known optimal error bounds that are valid, for example, for the symmetric
scheme. The above confirms the general conclusion that symmetrized locally
1D methods cannot serve as optimal methods for solving parabolic problems.
Difference Schemes for Nonlinear BVPS on the Semiaxis
Authors: Gavrilyuk I.P. , Hermann M. , Kutniv M.V. , Makarov V.L. 
Published: April 2013

Abstract The scalar boundary value problem (BVP) for a nonlinear second order
differential equation on the semiaxis is considered. Under some natural assumptions
it is shown that on an arbitrary finite grid there exists a unique three-point exact
difference scheme (EDS), i.e., a difference scheme whose solution coincides with the
projection of the exact solution of the given differential equation onto the underlying
grid. A constructive method is proposed to derive from the EDS a so-called truncated
difference scheme (n-TDS) of rank n, where n is a freely selectable natural number.
The n-TDS is the basis for a new adaptive algorithm which has
all the advantages known from the modern IVP-solvers. Numerical examples are given
which illustrate the theorems presented in the paper and demonstrate the reliability of
the new algorithm.
Numerical Solution of a Hyperbolic-parabolic System by Splitting Methods and Optimal Control Approaches
Authors: Agoshkov V.I. , Botvinovsky E.A. 
Published: April 2013

AbstractA new approach has been developed for solving the tide dynamics
problem, based on the splitting methods and the optimal control theory. We first
apply the classical splitting method for solving the problem. Then we use the optimal
control theory approaches to the system of equations obtained after the splitting. An
optimal control problem has been formulated for realizing a splitting method step.
We prove that the optimal control problem is well-posed and we propose an iterative
process of the minimization problem. The results of the numerical experiments are
presented.
Integration of Jacobi and Weighted Bernstein Polynomials Using Bases Transformations
Authors: Rababah Abedallah 
Published: April 2013

AbstractThis paper presents methods to compute integrals of the Jacobi polynomials
by the representation in terms of the Bernstein — B´ezier basis. We do this
because the integration of the Bernstein — B´ezier form simply corresponds to applying
the de Casteljau algorithm in an easy way. Formulas for the definite integral of the
weighted Bernstein polynomials are also presented. Bases transformations are used.
In this paper, the methods of integration enable us to gain from the properties of the
Jacobi and Bernstein bases.
Finite-order Integration Weights Can be Dangerous
Authors: Sloan I.H. 
Published: April 2013

Abstract Finite-order weights have been introduced in recent years to describe the
often occurring situation that multivariate integrands can be approximated by a sum
of functions each depending only on a small subset of the variables. The aim of this
paper is to demonstrate the danger of relying on this structure when designing lattice
integration rules, if the true integrand has components lying outside the assumed finiteorder
function space. It does this by proving, for weights of order two, the existence
of 3-dimensional lattice integration rules for which the worst case error is of order
O(N¯½), where N is the number of points, yet for which there exists a smooth 3-
dimensional integrand for which the integration rule does not converge.
Error Bounds of a Fully Discrete Projection Method for Symm’s Integral Equation
Authors: Solodky S.G. , Lebedeva E.V. 
Published: April 2013

Abstract The approximation properties of a fully discrete projection method
for Symm’s integral equation with a infinite smooth boundary have been investigated.
For the method, error bounds have been found in the metric of Sobolev’s spaces. The
method turns out to be more accurate compared to the fully discrete collocation method
known before.
A numerical method of bicharacteristics For quasi-linear partial functional Differential equations
Authors: ARLUKOWICZ P. , CZERNOUS W. 
Published: April 2013

Abstract
Classical solutions of mixed problems for first order partial functional differential equations in several independent variables are approximated by solutions of an Euler-type difference problem. The mesh for the approximate solutions is obtained by the numerical solution of equations of bicharacteristics. The convergence of explicit difference schemes is proved by means of consistency and stability arguments. It is assumed that the given functions satisfy the nonlinear estimates of the Perron type. Differential systems with deviated variables and differential integral systems can be obtained from the general model by specializing the given operators.
Approximate Solution Of The System Of Non-Linear Volterra Integro-Differential Equations
Authors: KHANI A. , MOGHADAM M.M. , SHAHMORAD S. 
Published: April 2013

Abstract
In this paper we develop a new method to find a numerical solution for the system of non-linear Volterra integro-differential equations (SNVE). To this end, we present our method based on the matrix form of SNVE. The corresponding unknown coefficients of our method have been determined by using the computational aspects of matrices. Finally the accuracy of the method has been verified by presenting some numerical computations.
An Adaptive Scheme to Handle the Phenomenon of Quenching for a Localized Semilinear Heat Equation with Neumann Boundary Conditions
Authors: Kouakou TH. K. , Boni TH. K. , Kouakou R. K. 
Published: April 2013

AbstractUnder some assumptions, we prove that the solution of a discrete form of the above
problem quenches in a finite time and estimate its numerical quenching time. We also
show that the numerical quenching time in certain cases converges to the real one when
the mesh size tends to zero. Finally, we give some numerical experiments to illustrate
our analysis.
Paralel Predictor-Corrector Schemes for Parabolic Problems on Graphs
Authors: Čiegis R. , Tumanova N. 
Published: April 2013

AbstractWe consider a predictor-corrector type finite difference scheme for solving
one-dimensional parabolic problems. This algorithm decouples computations on
different subdomains and thus can be efficiently implemented on parallel computers
and used to solve problems on graph structures. The stability and convergence of the
discrete solution is proved in the special energy and maximum norms. The results of
computational experiments are presented.
Lavrentiev Regularization and Balancing Principle for Solving Ill-Posed Problems with Monotone Operators
Authors: Semenova E.V. 
Published: April 2013

AbstractThe paper considers a method for solving nonlinear ill-posed problems
with monotone operators. The approach combines the Lavrentiev method, the fixedpoint
method, and the balancing principle for selection of the regularization parameter.
The method’s optimality has been proved for some set of smooth solutions. A test
example proves the efficiency of the proposed method.
On an Efficient Finite Element Method for Navier-Stokes-ω with Strong Mass Conservation
Authors: Manica Carolina C. , Neda Monika , Olshanskii Maxim , Rebholz Leo G. , Wilson Nicholas E. 
Published: April 2013

AbstractWe study an efficient finite element method for the NS-ω model, that uses
van Cittert approximate deconvolution to improve accuracy and Scott-Vogelius elements
to provide pointwise mass conservative solutions and remove the dependence of
the (often large) Bernoulli pressure error on the velocity error. We provide a complete
numerical analysis of the method, including well-posedness, unconditional stability,
and optimal convergence. Additionally, an improved choice of filtering radius (versus
the usual choice of the average mesh width) for the scheme is found, by identifying a
connection with a scheme for the velocity-vorticity-helicity NSE formulation. Several
numerical experiments are given that demonstrate the performance of the scheme, and
the improvement offered by the new choice of the filtering radius.
Layer-adapted methods for a singularly perturbed singular problem
Authors: Grossmann Christian , Ludwig Lars , Roos Hans-Görg 
Published: April 2013

Abstract In the present paper we analyze linear finite elements on a layer adapted mesh for a
boundary value problem characterized by the overlapping of a boundary layer with a
singularity. Moreover, we compare this approach numerically with the use of adapted basis
functions, in our case modified Bessel functions. It turns out that as well adapted meshes
as adapted basis functions are suitable where for our one-dimensional problem adapted bases
work slightly better.
QTT Representation of the Hartree and Exchange Operators in Electronic Structure Calculations
Authors: Khoromskaia Venera , Khoromskij Boris , Schneider Reinhold 
Published: April 2013

AbstractIn this paper, the tensor-structured numerical evaluation of the Coulomb and exchange
operators in the Hartree-Fock equation is supplemented by the usage of recent quantized-TT
(QTT) formats. It leads to O(log n) complexity at computationally extensive stages in the
rank-structured calculation with the respective 3D Hartree and exchange potentials discretized
on large n×n×n Cartesian grids. The numerical examples for some volumetric organic molecules
confirm that the QTT ranks of these potentials are nearly independent of the one-dimension
grid size n. Thus, paradoxically, the complexity of the grid-based evaluation of the Coulumb
and exchange matrices becomes almost independent of the grid size, being regulated only by
the structure of a molecular system. As a result, the grid approximation of the Hartree-Fock
equation allows to gain the high resolution with a guaranteed accuracy.
A Study of CFD Simulations of the Flow Pattern in an Agitated System with a Pitched Blade Worn Turbine
Authors: Skočilas Jan , Fořt Ivan , Jirout Tomáš 
Published: April 2013

Abstract
This paper presents a numerical analysis of an agitated fully baffled cylindrical vessel with a down pumping four blade worn or unworn pitched blade impeller (α = 45° and 30°) under a turbulent flow regime. CFD simulations predict the pumping capacity of the system equipped by worn and unworn pitched blade impeller. Experimental data were taken from the authors’ previous work and compared with results of numerical computations. A good agreement with experimental data was obtained. The ensemble-average mean velocity field with worn and unworn impellers was computed. It follows from the simulation results that the wear rate of the impeller blade has a significantly negative effect on the velocity distribution in an agitated liquid. The greater the destruction of the worn blade, the higher is the deformation of the velocity field around the rotating impeller, with a simultaneous decrease in impeller pumping capacity.
A Numerical Approach to Predict Sulphur Dioxide Emissions During Switchgrass Combustion
Authors: Peters Bernhard , Smuła-Ostaszewska Joanna 
Published: April 2013

Abstract
The demand for a net reduction of carbon dioxide and restrictions on energy efficiency make thermal conversion of biomass a very attractive alternative for energy production. However, sulphur dioxide emissions are of major environmental concern and may lead to an increased corrosion rate of boilers in the absence of sulfatation reactions. Therefore, the objective of the present study is to evaluate the kinetics of formation of sulphur dioxide during switchgrass combustion. Experimental data that records the combustion process and the emission formation versus time, carried out by the National Renewable Energy Institute in Colorado (US), was used to evaluate the kinetic data.
The combustion of switchgrass is described sufficiently accurate by the Discrete Particle Method (DPM). It predicts all major processes such as heating-up, pyrolysis, combustion of switchgrass by solving the differential conservation equations for mass and energy. The formation reactions of sulphur dioxide are approximated by an Arrhenius-like expression including a pre-exponential factor and an activation energy. Thus, the results predicted by the Discrete Particle Method were compared to measurements and the kinetic parameters were subsequently corrected by the least square method until the deviation between measurements and predictions was minimised. The determined kinetic data yielded good agreement between experimental data and predictions.
Does Globalization Affect Regional Growth? Evidence for Nuts-2 Regions in EU-27
Authors: Polasek Wolfgang , Sellner Richard 
Published: April 2013

Abstract
We analyze the influence of newly constructed globalization measures on regional growth for the EU-27 countries between 2001 and 2006. The spatial Chow-Lin procedure, a method constructed by the authors, was used to construct, on a NUTS-2 level, complete regional data for exports, imports and FDI inward stocks, which serve as indicators for the influence of globalization, integration and technology transfers on European regions. The results suggest that most regions have significantly benefited from globalization measured by increasing trade openness and FDI. In a non-linear growth convergence model, the growth elasticities for globalization and technology transfers decrease with increasing GDP per capita. Furthermore, the estimated elasticity for FDI decreases when the model includes a higher human capital premium for CEE countries and a small significant growth enhancing effect accrues from the structural funds expenditures in the EU.
Inter-frame Prediction with Fast Weighted Low-rank Matrix Approximation
Authors: Huang Zhi-Long , Hsiao Hsu-Feng 
Published: April 2013

Abstract
In the field of video coding, inter-frame prediction plays an important role in improving compression efficiency. The improved efficiency is achieved by finding predictors for video blocks such that the residual data can be close to zero as much as possible. For recent video coding standards, motion vectors are required for a decoder to locate the predictors during video reconstruction. Block matching algorithms are usually utilized in the stage of motion estimation to find such motion vectors. For decoder-side motion derivation, proper templates are defined and template matching algorithms are used to produce a predictor for each block such that the overhead of embedding coded motion vectors in bit-stream can be avoided. However, the conventional criteria of either block matching or template matching algorithms may lead to the generation of worse predictors. To enhance coding efficiency, a fast weighted low-rank matrix approximation approach to deriving decoder-side motion vectors for inter frame video coding is proposed in this paper. The proposed method first finds the dominating block candidates and their corresponding importance factors. Then, finding a predictor for each block is treated as a weighted low-rank matrix approximation problem, which is solved by the proposed column-repetition approach. Together with mode decision, the coder can switch to a better mode between the motion compensation by using either block matching or the proposed template matching scheme.
Methodology for 3D Video Subjective Quality Evaluation
Authors: Lewandowski Filip , Paluszkiewicz Mateusz , Grajek Tomasz , Wegner Krzysztof 
Published: April 2013

Abstract
The paper presents the methodology for 3D video subjective quality evaluation. Described methodology was designed to compare different 3D video compression technologies without an influence of any particular displaying or rendering technology. In addition detailed step by step description of test session design and preparation is provided. Experimental results for state-of-the-art 3D encoders are also included. All tests were conducted on two 3D monitors (polarization and autostereoscopic) thus influence of different displaying technologies on 3D video quality assessments has also been evaluated.
Joint Channel and Carrier Estimation Using Extended Kalman Filter
Authors: Haza Grzegorz 
Published: April 2013

Abstract
In this paper a proposal of joint channel and carrier estimation using extended Kalman filter (EKF) is presented. For the proposed algorithm simulations are performed and the results are compared with the separate channel estimation based on the Kalman filter (KF) and carrier estimation based on the extended Kalman filter (EKF).