bluuebunny/crossref_metadata_2025 huggingface dataset:
Solution of the Stokes Problem as an Inverse Problem
Authors: Agoshkov V. , Bardos C. , Buleev S.
Published: April 2013

In this study, we examine one of the approaches to the investigation and
solution of the Stokes equations: an original problem is regarded as an inverse problem
and then reduced to a problem of optimal control. Iteration algorithms are suggested
and results of numerical experiments are presented.
Solution of the Multi-interface Stefan Problem by the Method of Dynamic Adaptation
Authors: Mazhukin Vladimir , Chuiko Michail
Published: April 2013

The application of the dynamic adaptation method to the numerical
solution of multidimensional Stefan problems with explicit tracking of interfaces is
considered. The dynamic adaptation method is based on the idea of transition to
any non-stationary coordinate system. The results of the numerical experiment on
modelling the pulsed action of high-energy fluxes on metals are presented.
On Superconvergence of a Gradient for Finite Element Methods for an Elliptic Equation with the Nonsmooth Right–hand Side
Authors: Zlotnik Alexander
Published: April 2013

The elliptic equation under the nonhomogeneous Dirichlet boundary
condition in 2D and 3D cases is solved. A rectangular nonuniform partition of a
domain and polylinear finite elements are taken. For the interpolant of the exact
solution u, a priori error estimates are proved provided that u possesses a weakened smoothness.
Next error estimates are in terms of data. An estimate is established for the right–hand side f
of the equation having a generalized smoothness. Error estimates are derived in the case
of f which is not compatible with the boundary function. The proofs are based on some propositions
from the theory of functions. The corresponding lower error estimates are also included;
they justify the sharpness of the estimates without the logarithmic multipliers. Finally,
we prove similar results in the case of 2D linear finite elements and a uniform partition.
Spectrally Consistent Approximations to the Matrix Exponent and Their Applications to Boundary Layer Problem
Authors: Bobkov Vladimir V.
Published: April 2013

In an attempt to show maximum-norm stability and smoothing estimates for finite element discretizations of parabolic problems on nonquasi-uniform triangulations
we consider the lumped mass method with piecewise linear finite elements in one and two space dimensions. By an energy argument we derive resolvent estimate for the
associated discrete Laplacian, which is then a finite difference operator on an irregular mesh, which show that this generates an analytic semigroup in l_p for p‹∞
uniformly in the mesh, assuming in the two-dimensional case that the triangulations are of Delaunay type, and with a logarithmic bound for p=∞.
By a different argument based on a weighted norm estimate for a discrete Green's function this is improved to hold without a logarithmic factor for p=∞
in one dimension under a weak mesh-ratio condition. Our estimates are applied to show stability also for time stepping methods.
Applications of Primal-dual Interior Methods in Structural Optimization
Authors: Hoppe Ronald H. W. , Petrova Svetozara I.
Published: April 2013

We are concerned with structural optimization problems for technological processes in material science that are described by partial differential equations. In particular, we consider the topology optimization of conductive media in high-power electronic devices described by Maxwell equations and the optimal design of composite ceramic materials by homogenization modeling. All these tasks lead to constrained nonconvex minimization problems with both equality and inequality constraints on
the state variables and design parameters. After discretization by finite elements, we solve the discretized optimization problems by a primal-dual Newton interior-point
method. Within a line-search approach, transforming iterations are applied with respect to the null space decomposition of the condensed primal-dual system to find the
search direction. Some numerical experiments for the two applications are presented.
Analysis of a New Mixed Finite Volume Method
Authors: Mishev Ilya D.
Published: April 2013

A new mixed finite volume method for elliptic equations with tensor coefficients on rectangular meshes (2 and 3-D) is presented. The implementation of
the discretization as a finite volume method for the scalar variable (“pressure”) is derived. The scheme is well suited for heterogeneous and anisotropic media because
of the generalized harmonic averaging. It is shown that the method is stable and well posed. First-order error estimates are derived. The theoretical results are confirmed
by the presented numerical experiments.
Resolvent Estimate in L_p for Discretisations of Second Order Ordinary Differential Operators on Variable Grids
Authors: Grigorieff R. D.
Published: April 2013

In this paper, a resolvent estimate is proved for discretisations of second
order ordinary differential operators subject to Dirichlet boundary conditions on a finite
or infinite interval. As a discretisation method, a fully discrete Galerkin method using
continuous splines of order r > 2 on a locally quasi-uniform grid is considered. As a
byproduct, an a priori estimate for the discretised differential operator is obtained.
D-gap Functions for a Class of Equilibrium Problems in Banach Spaces
Authors: Konnov I. V. , Pinyagina O. V.
Published: April 2013

We consider rather a general class of equilibrium problems in a real Banach space, which involve nonsmooth convex functions. We apply the D-gap function
approach to these problems and show that, under certain additional assumptions, they can be converted into a problem of finding a stationary point of a differentiable function.
Based on this property, we suggest a descent type algorithm to find a solution to the initial problem. An example of applications to nonlinearly constrained equilibrium
problems is also given.
On Conditioning of a Schwarz Method for Singularly Perturbed Convection–diffusion Equations in the Case of Disturbances in the Data of the Boundary-value Problem
Authors: Shishkin Gregorii I.
Published: April 2013

In this paper we discuss conditioning of a discrete Schwarz method on piecewise–uniform meshes with an example of a one-dimensional singularly perturbed
boundary-value problem. We consider a Dirichlet problem for singularly perturbed ordinary differential equations with convection terms and a small perturbation parameter
ε. To solve the problem numerically we use an ε-uniformly convergent (in the maximum norm) difference scheme on special piecewise–uniform meshes. For this base scheme
we construct a decomposition scheme based on a Schwarz technique with overlapping subdomains, which converges ε-uniformly with respect to both the number of mesh
points and the number of iterations. The step-size of such special meshes is extremely small in the neighborhood of the layer and changes sharply on its boundary, that (as
was shown by A.A. Samarskii) can generally lead to a loss of well-conditioning of the above schemes. For the decomposition scheme we study the conditioning of the system
(difference scheme) and the conditioning of the system matrix (difference operator), and also the influence of perturbations in the data of the boundary-value problem on
disturbances of its numerical solutions. We derive estimates for the disturbances of the numerical solutions (in the maximum norm) depending on the subdomain in which
the disturbance of the data appears. It is shown that the condition number of the difference operator associated with the Schwarz method, just as for the base scheme,
is not ε-uniformly bounded. However, these difference schemes are well-conditioned ε-uniformly (with the ε-uniform estimate for the condition number being the same as
for the schemes on uniform meshes for regular problems) when the right-hand side of the discrete equations is considered in a “natural” norm, i.e., in the maximum norm
with a special weight multiplier. In the case
of the boundary-value problem with perturbed data we give conditions under which the solution of the iterative scheme based on the overlapping Schwarz method is convergent
ε-uniformly to the solution of this Dirichlet problem as the number of mesh points and the number of iterations increase.
Solution of Linear Equation Systems with a Dominant Skew-symmetric Part Using the Product Triangular Iterative Method
Authors: Chikina L. G. , Krukier B. L.
Published: April 2013

A new product triangular iterative methods for solving nonsymmetric linear systems of equations with positive real coefficient matrices based on the skewsymmetric part of the initial matrix are proposed. The convergence analysis for the new methods is presented.
Methods for Numerical Modeling of Two-Dimensional Capillary Surfaces
Authors: Polevikov Victor K.
Published: April 2013

Certain methods for numerical solving plane and axially symmetric
problems on equilibrium shapes of a capillary surface are presented. The methods
possess a high order of approximation on a nonuniform grid. They are easy to realize,
fairly universal and suitable for constructing not only simply connected but also doubly connected and disconnected surfaces, including strongly curved ones. It is shown
that the iterative algorithms constructed are absolutely stable at each iteration. The
condition for convergence of iterations is obtained within the framework of a linear
theory. To describe peak-shaped configurations of a magnetic
uid in a high magnetic field, an algorithm of generation of adaptive grid nodes in accordance with the surface
curvature is proposed. The methods have been tested for the well-known problems
of capillary hydrostatics on equilibrium shapes of a drop adjacent to the horizontal
rotating plate under gravity, and of an isolated magneticuid drop in a high uniform
magnetic field. It has been established that they adequately respond to the physical
phenomenon of a crisis of equilibrium shapes, i.e., they can be adopted to investigate
the stability of equilibrium states of a capillary surface.
A New Estimate of the Sing Method for Linear Parabolic Problems Including the Initial Point
Authors: Gavrilyuk Ivan , Makarov Vladimir L. , Vasylyk Vitaliy
Published: April 2013

For two new effcient methods for solving initial value problems in a Hilbert or Banach spaces based on a Sinc quadrature for an
improper Dunford-Cauchy integrals over a path enveloping the spectrum of the operator
we give a new unified estimate in the case of a Hilbert space.
Variational and Finite Element Analysis of Vibroequilibria
Authors: Beyer K. , Günther M. , Timokha K.
Published: April 2013

We 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

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

Effective 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

We 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

This 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

We 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

A 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

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.
Asymptotic Stability of a Three-level Operator-difference Scheme
Authors: Jovanović Boško S.
Published: April 2013

Asymptotic stability of linear three-level operator-difference schemes is
investigated in the case of commutative operators. Some new a priori estimates are obtained.
Difference Schemes for Nonlinear BVPS on the Semiaxis
Authors: Gavrilyuk I.P. , Hermann M. , Kutniv M.V. , Makarov V.L.
Published: April 2013

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

A 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

This 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

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

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

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

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

Under 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

We 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

The 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

We 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

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

In 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

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

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

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

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

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

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).
A comparison of two growing stock assessments by stratified sampling– how does accuracy of inventory affect our interpretation of the results
Authors: Jabłoński Marek
Published: April 2013

Since 1967, when the Polish State Forests were first inventoried, a continuous increase in the volume of growing stock has been recorded. This increase in timber resources is mainly the result of sustainable forest management. However, during this time period inventory methods have been changed a few times and this may have affected the estimates of of wood resources.

Since 2011 new instructions have been in place for forest management plans in the Polish State Forests. Despite this, the method of taking forest inventories remained consistent with the previous guidelines. This should allow us to consider changes in the volume of growing stock in relation to inventory methods and their accuracy.

In this paper, the results of growing stock estimations based on two assessments made using stratified random sampling are compared. After five years of inventories made for forest management plans, 422 sample plots in two forest districts were measured within 15 strata. Predicted age classes structure at the beginning of successive management plans was used to determine new strata. Data from two inventories were compared on the basis of age class. In addition, data from the State Forests Information System i.e. updated stand level inventory data (on felling and tree growth) were analyzed.

Comparing data from the two inventories, in three of seven age classes there was a decrease in the volume of growing stock after a five year period. We found no rational explanation for this. The extent of felling in the analyzed stand was very low, as confirmed by data from State Forests database. However, the largest decrease in volume was 1.5%, whereas the accuracy of growing stock assessment of discussed age class was estimated at some 9% in 2006 and 8% in 2011. Hence, from statistical viewpoint there was no differences between the results of both inventories.

However, the differences between volume of growing stock of examined age classes, updated in the Information System of the State Forests and results of assessments by stratified sampling are less than 95% confidence intervals for means of samples. Because of that, updated information could be used in the long term management planning. The results clearly suggest that changes of growing stock, estimated as a difference between two assessments, should be interpreted in conjunction with the accuracy of these inventories. The accuracy of sampling should be also taken into account when creating management plans.
Cardiorespiratory Fitness and Motor Skills in Relation to Cognition and Academic Performance in Children – A Review
Authors: Haapala Eero A.
Published: April 2013

Different elements of physical fitness in children have shown a declining trend during the past few decades. Cardiorespiratory fitness and motor skills have been associated with cognition, but the magnitude of this association remains unknown. The purpose of this review is to provide an overview of the relationship of cardiorespiratory fitness and motor skills with cognitive functions and academic performance in children up to 13 years of age. Cross-sectional studies suggest that children with higher cardiorespiratory fitness have more efficient cognitive processing at the neuroelectric level, as well as larger hippocampal and basal ganglia volumes, compared to children with lower cardiorespiratory fitness. Higher cardiorespiratory fitness has been associated with better inhibitory control in tasks requiring rigorous attention allocation. Better motor skills have been related to more efficient cognitive functions including inhibitory control and working memory. Higher cardiorespiratory fitness and better motor skills have also been associated with better academic performance. Furthermore, none of the studies on cardiorespiratory fitness have revealed independent associations with cognitive functions by controlling for motor skills. Studies concerning the relationship between motor skills and cognitive functions also did not consider cardiorespiratory fitness in the analyses. The results of this review suggest that high levels of cardiorespiratory fitness and motor skills may be beneficial for cognitive development and academic performance but the evidence relies mainly on cross-sectional studies.
Determining the Relationship Between Homocysteinemia and Biomarkers of Inflammation, Oxidative Stress and Functional Kidney Status in Patients with Diabetic Nephropathy
Authors: Čabarkapa Velibor , Đerić Mirjana , Stošić Zoran , Sakač Vladimir , Davidović Sofija , Eremić Nevena
Published: April 2013

Background: One of the leading causes of terminal renal failure is diabetic nephropathy. The aim of this study was to determine the relationship between homocysteine levels and the biomarkers of renal function, inflammation and oxidative stress, as well as the incidence of macrovascular complications in patients with diabetic nephropathy.

Methods: Sixty-four patients with diabetic nephropathy were included in this study. They were divided according to their homocysteine levels into two groups: hyperhomocysteinemic (HHcy, n=47) and normohomocysteinemic patients (NHCy, n=17). The re sults were compared to a control group (n=20) with normal renal function and without diabetes. Besides homocysteine, cystatine C, creatinine, urea, albuminuria, creatinine clearance, lipid status parameters, apolipoprotein A-I and B, lipo protein (a), CRP, fibrinogen, oxidative LDL were determined using appropriate methods. The incidence of macro vascular diabetic complications was also determined.

Results: The results indicate that the level of renal dysfunction is greater in HHcy than in NHcy patients (p<0.05). In HHcy patients levels of oxLDL were also higher compared to NHcy patients (119.3±140.4 vs. 71.4±50.8 ng/mL, disp< 0.05) as well as fibrinogen levels (4.3±1.3 vs. 3.7±0.8 g/L, p<0.05). The in cidence of macrovascular complications is more frequent in HHcy than in NHcy patients (55.3. vs. 35.3 %, p>0.05), and in patients with macroalbuminuria compared to patients with microalbuminuria (65% vs. 39%, p<0.05).

Conclusions: It can be concluded that HHcy is significantly present in patients with diabetic nephropathy, especially if there is greater reduction of renal function. Besides that, significantly higher concentrations of inflammatory (fibrinogen) and oxidative stress (oxLDL) markers were present in HHcy patients with diabetic nephropathy compared to NHcy patients.Therefore in diabetic nephropathy patients it is useful to regularly monitor the levels of homocysteine, as well as inflammatory and markers of oxidative stress.
Anemia and Anysocytosis in the Emergency Department: A Cross-Sectional Investigation
Authors: Lippi Giuseppe , Pipitone Silvia , Campana Valentina , Cervellin Gianfranco
Published: April 2013

Background: Anemia is a public healthcare problem, which is associated with increased morbidity and mortality. Some studies assessed the frequency of anemia in pediatric emergency departments (EDs), but no such information is available in adult patients admitted to the ED.

Methods: The study population consisted of adult patients admitted to the ED of the Academic Hospital of Parma during the year 2010 with the five most frequent acute pathologies (i.e., acute myocardial infarction, AMI), renal colics, pneumonia, pancreatitis and major trauma). Hospital re - cords were extracted from informatics database according to ICD-9 code and related terms. Routine hematological testing was performed on the entire population with identical instrumentation.

Results: The study population consisted of 462 ED patients (cases; 262 renal colics, 62 pneumonia, 51 acute pancreatitis, 46 AMI and 41 major trauma) and 429 healthy blood donors (controls). The median hemoglobin value was significantly lower in all patients than in controls (137 versus 151 g/L; p<0.01), whereas the median RDW value was significantly higher (13.7 versus 13.4%; p<0.01). The frequency of anemia and anysocytosis was higher in patients than in controls (anemia: 23 versus 4%, p<0.01; anysocytosis: 25 versus 16%; p=0.03). Hemoglobin values of all subclasses of patients were significantly lower than those of the controls, while those of RDW were significantly increased in patients with AMI, pancreatitis and pneumonia.

Conclusions: We found a high prevalence of anemia and anysocytosis in a population of ED patients, whose identification may be vital for appropriate therapy and subsequent management.
MYELOPEROXIDASE AND GLUTAMATE-CYSTEINE LIGASE POLYMORPHISMS IN TYPE 2 DIABETES MELLITUS: A PRELIMINARY STUDY / POLIMORFIZMI MIJELOPEROKSIDAZE I GLUTAMAT-CISTEIN LIGAZE U DIABETES MELLITUSU TIPA 2: PRELIMINARNA STUDIJA
Authors: Eksi Yunus Emre , Karaali Zeynep Ermig , Incekara Kutiuhan , Ergen H. Arzu
Published: April 2013

Background: Oxidative stress can accompany the physio- pathology of diabetes mellitus. Myelopercecidase and gluta- mate-cysteine ligase catalytic subunit are two important sub- stances which are connected with the maintaining of the redox balance in the body. In this study, the association be- tween diabetes, lipid levels, myeloperoxidase -463G/A, and the glutamate-cysteine ligase catalytic subunit -3506A/G gene polymorphisms have been investigated.

Methods: Frequencies of genotypes and alleles have been assessed using PCR-RFLP techniques in 90 type 2 diabetic patients and 70 healthy controls. Results: We found an association between myeloperoxidase -463 G/A genotype distributions (p=0.023) and allele distri- butions (p=0.009) in the study groups. In addition, there is a significant difference for each of the genotype (p=0.014) and allele (p=0.007) distributions for the glutamate-cysteine ligase catalytic subunit -3506A/G polymorphism.

Conclusions: Our study reveals the first data about the myeloperoxidase -463G/A and glutamate-cysteine ligase catalytic subunit -3506A/G gene polymorphisms for type 2 diabetes and we believe that this work will play a pioneering role for further studies.
The Effect of Wheat, Barley, and Oat Root System Interactions, in Two-Species Mixtures
Authors: Kaczmarek Sylwia , Matysiak Kinga , Krawczyk Roman
Published: April 2013

Pot experiments performed in the Institute of Plant Protection - National Research Institute were designed to determine the influence of the root systems of various spring cereal species sown in mixtures. The experiment used the Bryza variety of spring wheat, Antek variety of spring barley, and Cwał variety of oat, sown in two-species mixtures (8 + 8 plants per pot). In three of the six study objects, plastic sleeves were used at the time of sowing the seeds so as to separate the root systems of the cereal species under study. Cereals were harvested at full maturity. The height and number of stalks, the number of cereal spikes (panicles), dry root weight, dry stalk weight, the number of grains per spike (panicle), the 1,000-grain weight, and grain yield were established. The results have shown that the strongest competitor in the mixtures was barley. Barley also responded positively to the presence of both wheat and oat in the mixtures.
Susceptibility Level of the Pollen Beetle (Meligethes Aeneus F.) to Selected Pyrethroids in Poland, and Resistance Mechanisms of the Pest to Deltamethrin
Authors: Zamojska Joanna , Węgorek Paweł , Mrówczyński Marek
Published: April 2013

Pollen beetle susceptibility level to different insecticides has been investigated in Poland for several years. So far, high resistance to many of the insecticides’ active substances has been found. The work presents the current status of the pollen beetle susceptibility level to deltamethrin and beta-cyfluthrin, pointing to the beetle’s medium, high or very high resistance to both active substances. Also, pollen beetle resistance mechanisms to deltamethrin were investigated. Research, conducted with the use of oxidases, esterases and glutathione transferases blockers, showed that all three enzymes groups are involved in the pollen beetle resistance mechanisms to deltamethrin. The main role was played by oxidases and to a lower degree: esterases and glutathione transferases, respectively.
Bayes Signification Tests in Linear Regression and Economic Applications
Authors: Ciuiu Daniel
Published: April 2013

In this paper we will use the statistical inference, in particular the Bayes tests for the signification of the parameters of linear regression. We will consider the cases of known variance, and unknown variance respectively. Because we replace the Student tests by the Z tests in practice if the involved number of degrees of freedom is at least 30 , we can replace the case of unknown variance with that of known variance in our paper, if the above number of degrees of freedom is at least 30 . Because in economics we generally know the signs of the involved parameters, in practice the one-sided parametric tests are used. However, in this paper we will refer also to the two-sided Bayes test.
The Influence of Coating Fabrication Processes on the Optical Efficiency of Replicated Moiré Diffraction Gratings
Authors: Ribeiro João Eduardo
Published: April 2013

One of the most important parameters in the study of diffraction gratings is their optical efficiency. This paper analyzes the different manufacturing processes to cover gratings of Moiré interferometry and their influence on the quality and absolute efficiency of replicated gratings on the surfaces of specimens. The Moiré interferometry is a field measurement technique that has been used in many different fields such as applied mechanics, microelectronics, biomechanics or micromechanics, hence the importance of this study. The applied reflected coating was done by sputtering and aluminium vaporization processes. In this work different materials and thickness layers were analyzed. The obtained coatings have a high degree of reflectivity on the replicated gratings.