The paper deals with the application of Kalman filter for state variable estimation of the induction motor. The mathematical model of the extended Kalman filter used for rotor flux and speed estimation was presented. Some simulation results were shown in the paper. The influence of parameters of the induction motor equivalent circuit on the state variable estimation quality was demonstrated. The problem of suitable choice of Kalman filter parameters, such as elements of the covariance matrix Q, was also discussed. The possibility of practical realisation of such Kalman filter was discussed.

Most current geographic information systems assume and present the static world. But, new generations of GIS applications have much more demands in comparison to possibilities, which could provide traditional database management systems. Information that exists in the spatial database may be updated over time. Also, the very important demand is time capability to answer to state changing in database. 
The goals of our research activities are defining an active architecture, identifying the need for mediators in GIS, adding the active rules to the GinisNT spatial database and realize the active mediator level which perform active behaviour of the GinisNT. Paper describes how complete active database semantics can be supported on an existing framework by adding a mediator between the GinisNT spatial database and the client applications. ECA rules are fully supported through the ActiveMediator component without changing applications or the spatial database schema. The Active Mediator prototype provides integration of active and object-oriented features in one system. To provide support for temporal GIS application design and implementation, a suite of spatio-temporal object modelling and management technologies and tools has been developed constituting spatio-temporal object modelling and management system. The openness and scalability of developed frameworks enable their further improvement and refinement to satisfy the needs of specific, temporal GIS applications. Active, temporal GIS would improve understanding of the dynamic geographic processes caused by man, the nature or both, provide methods for detecting and analyzing trends and cycles in geographic phenomena, an would enable prediction of the future geographic states.

This paper deals with the influence of dust electrical resistivity on the electrostatic precipitator activity. Electrical resistivity is one of the critical parameters influencing fly ash collection by electrostatic precipitator. The electrical resistivity of fly ash depends on the chemical composition of the ash, the components of flue gases, and the temperature. Fly ash composition is largely determined by the type and composition of the coal being burned, and the furnace operating conditions. Precipitators work best, when the dust has a resistivity of between 102 and 1010 Wm. At lower resistivities the dust tends to fall off collecting electrodes and becomes re-entrained in the gas. At higher resistivities back-ionization becomes a problem.
During the macroscopic particles deposition on the collecting electrode the inhomogenities inside the deposited layer of dust and on the surface of layer appears. The anomalies appear of which the external demonstration is back corona. From the electro-physical point of view it is the solution of energy balance in the interface of medium: metal electrode – dust particle – air with the consideration of the combination of electrical forces, the acting of space charge and the creation of electron-ion conductivity in the layer of deposited dust particles.
Corona current from the discharge electrodes must pass through the collected dust layer on the plates to reach grounded collecting plate surfaces. Passage of the current builds up a voltage across a dust layer in accordance with Ohm’s law. Theory and experience indicate that when the dust resistivity exceeds a critical value of about 1012 Wm, corona current is limited by electrical breakdown in the collected dust layer. This limits useful operating voltage and reduces precipitator efficiency.

Artificial neural networks are recently showing good promise for application in power electronics and motion control system. They have been applied mainly in control of converters and drives. Sensorless control of the induction motor drives requires knowledge of the instantaneous value of the rotor speed. Various methods of the rotor speed estimation were recently used, based on the mathematical models of the induction machine, on non-linear phenomena of the motor and based on neural networks. This paper deals with utilisation of artificial neural networks (ANN) for observing an induction motor drive variables. The observing is realised utilising several quasi-single estimators, number of those is equal to number of observed variables. The observers are based on feed-forward neural network and on cascade-forward backpropagation ANN, respectively. The structure of the neural network is analogues to the mathematical model of an induction motor. Stator currents and stator voltages of the induction motor are inputs of the neural network. Estimation is based on off-line learning principle using backpropagation algorithm with Levenberg-Marquardt algorithm. The simulation using Matlab with Simulink realises the application results. Rotor flux, torque and angular speed of an induction motor are estimated. Changes in the rotor resistor do not influence the quality of observing. 
The results of simulated experiments indicate that a neural network can be an alternative way to other estimation methods.

The purpose of this article is to show how electrical and thermal field exercise an influence on life-time of insulation material. Fist of all simple ageing is described. When thermal stress is analyses, the Arrhenius’s law is used together with chemical kinetic reaction theory. From theses assumption thermal classes of each material applied in insulation system can be determined. Nowadays there is material with class F. It is ReMica material based on mica, epoxy resin and textile base. After thermal heating it is prepared for industry used. It is necessary to know the influence of temperature during production and service, because ageing mechanism can be change if certain boundary above thermal class is overcame. The same situation is during electrical stress. For thermoplastic materials the sufficient theory isn’t present nowadays, especially for critical limits. Finally the combination of both brings their interaction. The influence from single stresses can’t be cumulated without correction.

In this paper non-linear dynamical system is controlled using a predictive control strategy. This control technique needs a model of the system, which can predict the output of the system. The non-linear identification can be done using neural feed forward model as a predictor. The predictive control strategy is based on the on-line optimisation of a cost function. The on-line minimization is done using Levenberg-Marguardt algorithm by simulation language MATLAB.

Genetic algorithms are quite often presented as a panacea that is suitable to almost any problem and is going to replace traditional techniques. They are oversimplified, oversold and their real potential is very often overestimated. In order to avoid some mistakes related to genetic algorithms application and to prevent frustration associated with that it is necessary as in the other fields of human activities to learn from faults that were done before. To be able to do it these failures must be recorded, described, and analysed. 
Unfortunately, there are just a few contributions whose authors have confessed a failure when attempting to apply genetic algorithms to a particular problem and who has analysed such a disappointment. When one gets deeper into genetic algorithms field it is easy to realise that these algorithms are definitely not a kind of tool that is applicable immediately and to whichever problem without sufficient understanding the essence of the particular problem. Having understood the nature of the particular problem we might be able to design a hybrid evolutionary algorithm that might be a very competitive one or we might reach a conclusion that it is not a good idea to employ an evolutionary inspired approach. We do believe that there are some very good reasons that can help us to indicate potential problems and that is why we are going to describe them here in a greater detail.

Often goal interference and wittingly obstruction are antenna systems use in radar technology alternatively in communication systems. A expedient on solving problems incident with activity interferences and unwanted signals is applique adaptive antenna systems. Specific facilities this systems are used on safekeeping of radars and communication systems from interference, when a tendency of approach interference isn't noted in advance. Antenna array is important component of adaptive antenna system. It realizes a lot of-channel middle of receipts of signals. On achievement spatial selectivity is needs implement receipts of signals with antenna system, which is composite from two alternatively several spatial arrangement elements. For area adaptive antenna systems are used prefer linear antenna systems and singular plane antenna systems in period. For many applications in smart technology is needed to design antenna system with much good directional alternatively omnidirectional properties. Appropriate procedure what is used on achievement directional alternatively omnidirectional facilities is to configure individual antenna elements from those is created antenna array into various geometrical structures.
The article alocates on solution directional functions structured cylindrical antenna system, by means of which is possible to form wide spectrum radiation patterns for different application exploitation. The structured cylindrical antenna system we classe among space distributed antenna system. In this article is mention contrasts in solution antenna systems with different oriented dipoles. A solution of antenna system with dipoles oriented other as in tendency z-axis is essentially serious from aspect analytical solution but also by numeric solution on computing technics. This antenna array is assigned for applications in region adaptive antenna systems, where it exploit preferences omnidirectional pattern.

How to cancel the software crisis? To prove that programs are reliable. But it is possible only in mathematics. So, the programming has to use mathematics. In this paper we present basic mathematical concepts that enable to start discussion about the theory of programming in the framework of the classical mathematical logic, an axiomatic set theory, category theory, and universal algebra.

In this article is presented a simple method for transient stability assessment of a single machine-infinite bus power system using catastrophe theory. Catastrophe theory is a mathematical technique for the qualitative analysis of system equations, defining the jump phenomena and sudden changes caused by smooth alterations in the situation. 
The computation of critical fault clearing time and critical fault clearing angle has been demonstrated and compared with results obtained by the numerical step-by-step method. The technique is performed in such a way that individual machine energies are balanced. It is valid for any fault type or location and is effective for on-line stability assessment.

Developments in semiconductors drive power electronic into transmission and distribution applications as solution of power flow control and voltage stability problems. Advances in power semiconductor technology and power electronic equipment have provided a means for fast and smooth control of three system parameters that have a direct impact on power flow: the bus voltage, the line impedance and the transmission angle [8]. This paper describes new means of power electronic concrete FACTS (Flexible Alternating Current Transmission Systems) devices. These devices can fulfil functions of reactive shunt compensation, series compensation, phase shifting, series voltage injection device and shunt current injection device or a combination of these. This article describes individual FACTS devices and their application for voltage and power flow control.
Installation of FACTS devices on key locations in a electric power network increases the network's controllability. By using these devices we can push transmission lines to their thermal limits [3]. This way we can update existing lines and delay construction of new lines. We also add flexibility which may be used to increase the efficiency of energy transfer and decrease the cost of generation. FACTS devices have been successfully applied in many countries. This paper describes in brief some examples of these applications. 
This article also describes the Distributed Superconducting Magnetic Energy Storage System (D-SMES). Advantage of this system is the combination of superconducting and semiconductor technology.