Our aim in this paper is to count the zero points of the solutions of the second order differential equation (r(t)u'(t))'+ p(t)u(t) = 0. (E+) The sufficient conditions for the equation (E+) to be oscillatory are also presented.

Please find the abstract in the attached paper

An article says about the basic magnetic features of ferromagnetic material, which need to be taken to the consideration when designing model of elastomagnetic sensor. Mentioned is an intelligent calculator, which is used for calculation of change of sensor permeability in cubic grate in dependence of the lay of vectors of magnetostriction and external field. In the article, the sensor model in program PSPICE is described. Model in program PSPICE simulates a real hysterezis loop of sensor, his loses, his dependency from the frequency and the entry signal. Realized is by passive elements and controlled current sources the way it could simulates real entry signal and also the shape of the hysterezis loop. In the conclusion of the article, the hysterezis loop of real sensor of a torque is showed. The basic requirements for the sensor model were simplicity, accuracy, comprehensibility, open system and further utility for similar types of sensors.

This paper deals with computation of harmonic current flows and voltages in three phase systems using by a nodal method. The nodal method is useful to determinate unknown branch currents and nodal voltages by known source voltages or currents and nodal admittance matrix of the network. To obtain the correct solution it is necessary to correctly determinate the nodal admittance matrix, which contains admittances of three-phase elements. This article is also describing the ways how to model some three-phase elements for the purpose of nodal method analysis.

The paper is focused on Predictive Control Algorithm design for time-invariant state space models of dynamic systems with various dynamics, (mechanical system-helicopter, hydraulical system - three tanks with interaction). The predictive control algorithm based on state space models is verified by simulation schemes in language Matlab/Simulink using architecture of S-functions of the library PredicLib. The results are presented by created Internet applications using the technology Matlab Web Server. Internet applications enable to simplify the usage of designed predictive algorithms for testing their properties at various dynamics of MIMO non-linear systems without the proper installation language Matlab/Simulink on client’s PC.

This paper deals with basic principles of metaprogramming and reflection with connection to aspect-oriented programming (AOP). Metaprogramming is about writing programs that represents and manipulate other programs or themselves, i.e. metaprograms are programs about programs. The impact of metaprogramming is obvious in traditional development processes, by sorting existing programs as transformational processes with inputs and outputs. Open implementation and metalevel architectures are related to their reflective properties. Reflection is an entity’s integral ability to represent, operate on and otherwise deal with itself in the same way that it represents, operates on, and deal with its primary subject matter. Structural reflection represents the ability of a program to access a representation of its structure, as it is defined in the programming language. Behavioural reflection represents the ability of a program to access a dynamic representation of itself, that is to say, of the operational execution of the program as it is defined by the programming language implementation (processor). AOP allows development of required application using principle of separation of concerns. Reflection and AOP share many similarities in concepts, possibilities and applied techniques. There are several solutions to provide a reflective system among which belong following approaches: MetaclassTalk, Geppetto Reflex and Iguana/J. The former two are systems based on Smalltalk - Squeak; the latter two are based on Java.

In the article presented we deal with one method of stochastic programming – probabilistic programming. It is a programming in which the probabilities of the values of the variables are of interest. Our approach is that solving problem we can construct in logical reasoning over some mathematical theories. In this approach we use category theory for construction of type theory and of the logical system. Then we formulate the logical theory to enclose the solution of the problem. These steps we show at well-known examples: the random number generator and the Blackjack game.
 

The article presents possibilities of distance remote via Internet. The Internet protocols divided by OSI model that can be used for controlling and regulations are discussed with final focusing on TCP and UDP protocols and comparing these protocols from the controlling point of view. The paper is analyzing advantages and disadvantage of using the Internet in different level of the existing levels in the information hierarchy and the delay time problem in communication via Internet. The item compares more buses used in distance remote. It contains also some distance remote control system proposal.

The study of the Power flow is very significant, because it makes it possible to provide information of large importance; in order to better plan, to control and ensure finally the correct operation of the electrical supply networks. In our article, we present a method of calculation of the flow of powers in a mixed electrical supply network in high voltage (AC/DC). This method called also method SPI: (Substituted Power Injection) makes a small modification to the level of the bus of connection DC. The calculation of the active and reactive powers at the final bus of system AC-DC, are obtained by the subtraction of the powers of the converters and those which are specified with the bus of connection DC. This method will be applied to the 14 bus networks.

In the presented paper we deal with the determination of magnetic field in the elastomagnetic sensor core. The elastomagnetic sensor core consists of the ferromagnetic plates which thickness is negligible to the rest of the core dimensions so it is sufficient to solve the magnetic field in one core plate. The dimension of the plate is designed in such a way that the plate can be divided into the squares a number of which is equal to a number of the holes in each plate. Each of the square is called as an integrative element of the sensor and the magnetic field in such one is solved. The magnetic field in this integrative element is computed by using Partial Differential Equation Toolbox of MATLAB that provides effectual tool for the solution of partial differential equations in two space dimensions and time. The use of this toolbox requires only a basic level of the partial differential equation knowledge what is considered to be the most important advantage of this toolbox. The magnetic field in the integrative sensor element for the plane case can be expressed by the elliptic partial differential equation for the magnetic vector potential. The partial differential equation coefficients are magnetic permeability and the current density for the domain in which the magnetic vector potential field is solved. The domain consists of three subdomains so the coefficients in each of these regions have to be determined. For the subdomain that represents ferromagnet the functionality between the magnetic permeability and the magnetic flux density is needed because ferromagnet permeability is dependent on the field strength. The boundary conditions specifying for the outer boundaries and the interior ones is the necessary part of the PDE problem formulation too. The toolbox provides execution the most of hard work such as the mesh generation, the partial differential equation transformation to the discrete form by the finite element method and the approximation to the solution itself. The results can be visualized in several ways. In our case the equipotential lines of magnetic vector potential in the integrative sensor element are selected.