Communications - Scientific Letters of the University of Zilina, 2010 (vol. 12), issue 1
Articles
Applications of the Fractional Calculus: On a Discretization of Fractional Diffusion Equation in One Dimension
Tomas Kisela
Communications - Scientific Letters of the University of Zilina 2010, 12(1):5-11 | DOI: 10.26552/com.C.2010.1.5-11 
The paper discusses the problem of classical and fractional diffusion models. It is known that the classical model fails in heterogeneous structures with locations where particles move at a large speed over a long distance. If we replace the second derivative in the space variable in the classical diffusion equation by a fractional derivative of order less than two, we obtain the fractional diffusion equation (FDE) which is more useful in this case. In this paper we introduce a discretization of FDE based on the theory of the difference fractional calculus and we sketch a basic numerical scheme of its solution. Finally, we present some examples comparing...
Orthogonal Polynomials and Related Special Functions Applied in Geosciences and Engineering Computations
Vladimir Guldan, Mariana Marcokova
Communications - Scientific Letters of the University of Zilina 2010, 12(1):12-15 | DOI: 10.26552/com.C.2010.1.12-15
In applications of mathematics involving either the Laplace or the Helmholtz equation in spherical coordinates the associated Legendre equation occurs. Its solutions are called associated Legendre functions. They have some relations to classical Legendre orthogonal polynomials and classical Jacobi orthogonal polynomials. The classical Legendre polynomials and the associated Legendre functions have been used by some authors at the approximation of length of curves and cylindrical surfaces and the approximation of Earth shape in geosciences and engineering computations. In the present paper we investigate some relations between these functions pointing...
Stress Field Distribution in Magnetoelastic Pressure Force Sensor
Iveta Tomcikova, Dobroslav Kovac, Irena Kovacova
Communications - Scientific Letters of the University of Zilina 2010, 12(1):16-19 | DOI: 10.26552/com.C.2010.1.16-19
Modelling of the stress field distribution in a magnetoelastic sensor core is proposed. The components of stress field are carried out by a numerical solution of boundary-value problem for stress field. The obtained results are presented in graphical form.
Partial Differential Equation for Heat Conduction and Its Solvability
Ondrej Kovacik, Pavol Orsansky
Communications - Scientific Letters of the University of Zilina 2010, 12(1):20-22 | DOI: 10.26552/com.C.2010.1.20-22
This paper deals with the heat conduction equation which is a model of thermomechanical processes in the special case. The considered case is based on the nonstandard type of coefficients in this equation.
Analysis of Complex Time Function of Converter Output Quantities Using Complex Fourier Transform/Series
Maria Zaskalicka, Pavel Zaskalicky, Mariana Benova, Mahmud A. R. Abdalmula, Branislav Dobrucky
Communications - Scientific Letters of the University of Zilina 2010, 12(1):23-30 | DOI: 10.26552/com.C.2010.1.23-30
The paper deals with the complex- and discrete Fourier transform which has been considered for both three- and two phase orthogonal voltages and currents of systems. The investigated systems are power electronic converters supplying alternating current motors. Output voltages of them are strongly non-harmonic ones, so they must be pulse-modulated due to requested nearly sinusoidal currents with low total harmonic distortion. Modelling and simulation experiment results of half-bridge matrix converter for both steady- and transient states are given under substitution of the equivalence scheme of the electric motor by resistive-inductive load and back...
Better Confidence Intervals for a Binomial Proportion
Ivana Pobocikova
Communications - Scientific Letters of the University of Zilina 2010, 12(1):31-37 | DOI: 10.26552/com.C.2010.1.31-37
Interval estimation of a binomial proportion is one of the basic problems in statistics. In technical practice a binomial proportion is often used in statistical quality control. The standard Wald interval and the exact Clopper-Pearson interval are the most common and frequently used intervals. They are presented in the majority of statistical literature. It is known that the Wald interval performs poorly and this interval should not be used. In this paper we recommend the alternatives of confidence intervals that have a better performance and are appropriate for practical use. We compare the performance of six alternatives of confidence intervals...
Mathematical Foundations of Cartography
Darina Stachova
Communications - Scientific Letters of the University of Zilina 2010, 12(1):38-43 | DOI: 10.26552/com.C.2010.1.38-43
The aim of this contribution is to acquaint the reader with a specific part of mathematical cartography that is interesting not only from the point of view of mathematics, but also from the point of view of constructive geometry.
Mathematical Models for Acoustic Spectra Simulation
Peter Hockicko, Peter Bury, Peter Sidor, Stanislav Jurecka, Igor Jamnicky
Communications - Scientific Letters of the University of Zilina 2010, 12(1):44-49 | DOI: 10.26552/com.C.2010.1.44-49
The experimentally obtained acoustic spectra of some investigated materials; particularly the ion conductive glasses and MOS (metal-oxide-semiconductor) structures are analyzed using suitable theoretical models and mathematical procedure to fit the experimental data. The acoustic spectra of ion conductive glasses can reflect the basic features of the relaxation and transport processes of the mobile ions. The results obtained form acoustic deep level transient spectroscopy (A-DLTS) spectra of MOS structures are used for the characterization of deep centers and determination of some of their physical parameters. Suitable theoretical model and mathematical...
Perceptual Analysis of L2 Phonic Competence
Tomas Lengyelfalusy, Zdena Kralova
Communications - Scientific Letters of the University of Zilina 2010, 12(1):50-54 | DOI: 10.26552/com.C.2010.1.50-54
The research is focused on the quality of English pronunciation of Slovak native speakers reflected in the score of perceptual evaluation by English native speakers. The primary objective is to detect the improvement of English phonic competence after the metaphonetic input focused on the contrastive analysis of the Slovak and English segmental systems.
Experimental Behavior of Jurik's Nearest Point Approach Algorithm for Linear Programming
Ondrej Such
Communications - Scientific Letters of the University of Zilina 2010, 12(1):55-57 | DOI: 10.26552/com.C.2010.1.55-57
T. Jurik recently proposed a new algorithm for solving linear programming problems. The algorithm is iterative, finding points on the boundary of the problem's convex polyhedron. Global convergence of the algorithm is an open question. Jurik benchmarked the performance of the algorithm on standard sets of linear optimization problems, and the algorithm was on par with commonly used ones, and sometimes beating the simplex method by a wide margin. In this note we concentrate on testing local behavior of the algorithm near a vertex in the three dimensional Euclidean space. Our experiments indicate that the behavior of the algorithm is mostly very fast,...
Clustering of Slovak Sentence Melody - Methods and Results
Maria Cernanska, Ondrej Skvarek
Communications - Scientific Letters of the University of Zilina 2010, 12(1):58-64 | DOI: 10.26552/com.C.2010.1.58-64
Modern speech synthesis systems implement prosody features to achieve more naturally sounding voices, trying to produce sounds similar to the human speech. This article deals with obtaining one of prosody characteristics (sentence melody contour) from human speech recordings. Similarities of melody contours are studied using cluster analysis. Several clustering methods are evaluated for this purpose, estimation of proper number of clusters is described and typical melodies for different types of Slovak language sentences (declarative, interrogative, exclamatory, clauses with final "," etc.) are found and recommended for implementation in our text-to-speech...
Implementation of Environmental Management Systems in the Slovak Republic
Milan Majernik, Jana Chovancova
Communications - Scientific Letters of the University of Zilina 2010, 12(1):65-69 | DOI: 10.26552/com.C.2010.1.65-69
The human environment is always influenced by enterprise activity, which is mostly negative. The introduction of an Environmental Management System (EMS) can be an important step towards fulfilling the principles of sustainable development on a practical level. However, there are few ways of EMS implementation. Authors of the paper present and analyze possible approaches of EMS implementation in Slovak enterprises. According to this analysis possible development trends in the environmental management can be indicated.
Integrated Management Systems
Jana Chovancova, Milan Majerník, Jana Jurikova
Communications - Scientific Letters of the University of Zilina 2010, 12(1):70-74 | DOI: 10.26552/com.C.2010.1.70-74
Over the past few years an increasing number of companies certified according to the requirements of ISO 9001:2008 for Quality Management System (QMS) but also according to the requirements of other standards, for example environmental management system according to ISO 14001:2004 (EMS) and / or a management system for Occupational Health & Safety Management System, according to OHSAS 18001:2007, or other standards (ISO 22000, ISO 27000, etc.) can be seen in industrial sector and in services as well. Integration of management systems has become a key aspect of more sustainable management of a company. The aim of paper is to (1) better explain role...