September 2005, Volume 5, Number 3
MOKHTARI, N., ZEBLAH, A., LOUSDAD, A., MASSIM, Y.: Modelisation and Optimization of Squirrel-Cage Using Orthogonal Designs |
Perić, H. Z., Stefanović, Č.
M.,Jovanović,
Ž. A.: Analysis of Some New Approximations of Piecewise Uniform Polar Quantization |
KOVÁČOVÁ,
I., KAŇUCH, J., KOVÁČ, D.: EMC of Electrical Systems – Galvanic Coupling (Part I.) |
TURÁN,
J., OVSENÍK, Ľ., TURÁN, J. Jr.: Optically Powered Fiber Optic Sensors |
MOKRIŠ,
I., SKOVAJSOVÁ, L.: Neural Network Model of System for Information Retrieval from Text Documents in Slovak Language |
MERNIK, M., ČREPINŠEK, M.: Prolog and Automatic Language Implementation Systems |
NOVITZKÁ.V.: Logical Reasoning about Programming of Mathematical Machines |
KAJAN,
E.: The Fundamental Technologies for Open B2B – A Survey |
Gamcová, M., Marchevský, S., Gamec,
J.: Lokalizácia pozície chyby estimácie pohybu |
Záskalický, P.Záskalická, M. Vlastnosti dvojfázového synchrónneho motorčeka s permanentnými magnetmina rotore pri napájaní cez triak z jednofázovej siete |
Summary: |
MOKHTARI, N., ZEBLAH, A., LOUSDAD, A., MASSIM, Y.: Modelisation and Optimization of Squirrel-Cage Using Orthogonal Designs [full paper] In terms of general approach the problem of optimal design and construction is considered. In the present paper an optimization method is elaborated and takes on the process in establishing mathematical models for conducting real procedure that allows an optimal design and construction of asynchronous electrical motor of 13kW. The proposed method is a multi-objective optimization approach that determines the most influencing parameters and there interaction effects on both the economical function and the desired performances using design of experiment. The Strategy adopted avoids cumbersome computations used in traditional optimization techniques.
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Perić, H. Z.Stefanović, Č. M.Jovanović, Ž. A.: Analysis of Some New Approximations of Piecewise Uniform Polar Quantization [full paper]In this paper the piecewise uniform polar quantization of Gaussian source is analyzed. Simultaneous inside the rings after the first partition the constant probability density function of input signal vector amplitude is supposed. For this case and for the given code rate we optimized the granular distortion in order to get the manner of total points number distribution per rings after the first partition; than the manner of the second partition, i.e. we evaluated the expressions for amplitude levels number and the phase levels number on one amplitude level. Also we found the expression for granular distortion which we used to estimate the suggested model. Namely, we compare the obtained signal to quantization noise ratio with the known optimal ratio and on these bases we conclude, among the other things, under which condition the suggested approximation can be applied.
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KOVÁČOVÁ,
I., KAŇUCH, J., KOVÁČ, D.: EMC of Electrical Systems – Galvanic Coupling (Part I.) [full paper] This papers deals with the analysis of the electromagnetic compatibility (EMC) - galvanic coupling problems focused to the area of power electrical systems. Description of galvanic coupling problem is divided into two separate parts according the length of common conductors or the working frequency. First part (PART I.) is dealing with the galvanic coupling problem of concentrated parameter circuits, it means such that the length of common conductors is short or processed signals have low working frequency. The second one (PART II.) is analyzing the same problem for circuits with distributed parameters, it means such that the length of common conductors is long or processed signals have high working frequency. For detail problem investigation a mathematical analysis, computer simulation method and verification measuring are used, too.
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TURÁN,
J., OVSENÍK, Ľ., TURÁN, J. Jr.: Optically Powered Fiber Optic Sensors [full paper] In this paper a review of optically powered fiber optic sensors is presented. The basic properties, key elements (photovoltaic power converters) and possible generalized sensory system architectures are discussed. A brief outlook on recent developments and industrial applications is presented
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MOKRIŠ,
I., SKOVAJSOVÁ, L.: Neural Network Model of System for Information Retrieval from Text Documents in Slovak Language [full paper] The aim of the paper is to describe the information retrieval model which retrieves the information from the text documents in Slovak language and which, for this purpose, uses the neural networks. This model comes from linguistic and conceptual approach for the analysis of text documents in Slovak language. The neural network model, based on multilayer perceptron and spreading activation network type, accepts the structure of conceptually and linguistically oriented model, where problems of document database creation and document indexing for keyword determination are solved. Proposed structure of the neural network model solves the problem of the document retrieval on the base of user's question. However, learning algorithm and neural network invariance, come from utilization of the neural networks, enable the decrease of the computational complexity of the language analysis algorithm.
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MERNIK,
M., ČREPINŠEK, M.: Prolog and Automatic Language Implementation Systems [full paper] In the paper the use of Prolog, their benefits and drawbacks in automatic language implementation systems are presented. Various formal methods such as attribute grammars, operational semantics and denotational semantics are briefly described and implemented in Prolog. The advantages of Prolog basically stem from the use of unification and nondeterminism, and the price paid for the advantages are slower execution times. Various Prolog implementation of formal semantics method show that Prolog is viable tool for programming language development, design and prototyping.
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NOVITZKÁ.V.: Logical Reasoning about Programming of Mathematical Machines [full paper] We always start the solving of a problem with the formulation of its theoretical foundations. If we would like to use mathematical machines (computers) in problem solving, we need to formalize its theoretical foundations as logical reasoning because the programs should really prove the correctness of their results. In our paper we present central ideas of our approach regarding programming as logical reasoning. Our first idea is that the theory in which we reason is the type theory starting with basic types. Our second idea is that the running program is actually a proof in the theory above formulated as the intuitionistic linear version of Gentzen's calculus. We show that such a synthesis of categorical and linear logic forms a theoretical foundations of programming for mathematical machines.
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KAJAN,
E.: The Fundamental Technologies for Open B2B – A Survey [full paper] B2B is a strong multidisciplinary research field with many constituent disciplines and technologies. This paper deals with the B2B interoperability in the sense of open component and framework standards. In particular, underlying network technologies, protocols, the components and concepts of Web intelligence, and the frameworks for B2B interoperability are described. All technologies described are covered by an overview of relevant standards. Concluding remarks emphasize a critical overview of the current state of B2B openness and future directions in research and standardization in terms of fundamental technologies described here. The most of discussed issues are of wider interest for many e-applications.
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Gamcová, M., Marchevský, S., Gamec,
J.: Lokalizácia pozície chyby estimácie pohybu [full paper] This paper presents the analysis of errors produced by block matching motion estimation methods with lower computational cost (fast search algorithms). We try to find an answer on the question what model of distortion can be used and which motion vectors are founded as fault (corrupted by noise). We consider the vector fields obtained by using of full search algorithm (FSA) as lossless data. We take the vectors of movement obtained by using 2D logarithmic (2D log) search procedure as data corrupted by noise. The results of analysis can help optimize post processing of motion vectors in endeavouring to reduce computational cost or regularize vector fields.
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Záskalický,
P.Záskalická, M. Vlastnosti dvojfázového synchrónneho motorčeka s permanentnými magnetmina rotore pri napájaní cez triak z jednofázovej siete [full paper] A synchronous motor with ferrite permanent magnet rotor is a good solution for small pump applications. Strontium-ferrite based permanent magnets are attractive for application in electric machines due to several reasons. Their price is relative low. They are chemically inert, which make them suitable for application in aggressive environments. Strontium-ferrite magnets have high specific electric resistance, so they do not experience thermal problems due to eddy-current losses. On the other side, their low residual flux density imposes the need for special machine construction when high air-gap flux density is needed. It also has some drawbacks. The most important of them seems to be its inability to start directly on the mains, Permanent magnet motor has to by equipped with an electronic circuit for direct starting, which increases motor price. Another drawback is the torque ripple for the non- harmonic supply. This paper shown analytical calculation of the torque ripple of the small permanent magnet motor, which does a triac converter supply. The converter forms a two supply triacs in each phase of motor, connected on one-phase 50Hz mains.
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