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Kosice, Slovakia

Technical University of Košice is the second largest university of technology in Slovakia. Wikipedia.

Pocs J.,Slovak Academy of Sciences | Pocs J.,Technical University of Kosice
Information Sciences

We provide a generalization of fuzzy concept lattices based on so-called weak Galois connections. Generalization is that instead of dually isomorphic closure systems we consider dually isomorphic retracts of complete lattices. We also give a generalization of the concept lattices with hedges, proposed by Bělohlávek and Vychodil, based on composition of interior operators with Galois connections. © 2012 Elsevier Inc. All rights reserved. Source

Petr I.,Technical University of Kosice
Computers and Mathematics with Applications

This paper deals with the Bloch equations which are a set of macroscopic equations that are used for modeling of nuclear magnetization as a function of time. These equations were introduced by Felix Bloch in 1946 and they are used for a description of the Nuclear Magnetic Resonance (NMR). This physical phenomenon is used in medicine, chemistry, physics, and engineering to study complex material. Fractional-order generalization of the Bloch equations was presented by Richard Magin et al. in 2008 as an opportunity to extend their use to describe a wider range of experimental situations involving heterogeneous, porous, or composite materials. In this paper we describe numerical and simulation models (created for Matlab/Simulink) of the classical and the fractional-order Bloch equations. The behaviour and stability analysis of the Bloch equations are presented as well. © 2010 Elsevier Ltd. All rights reserved. Source

Vagaska A.,Technical University of Kosice
Applied Mechanics and Materials

The article is focused on the actuator with one pneumatic artificial muscle and spring which counteracts the tensile force of the artificial muscle. Such a solution requires only one inlet and one outlet electromechanical pneumatic valve. It is suitable for the synthesis of so-called low cost bioservosystems. The paper presents mathematical description and static characteristics of individual parts of the actuator and also characteristics of the all mechanism. © (2014) Trans Tech Publications, Switzerland. Source

Myskova H.,Technical University of Kosice

Max-min algebra is an algebraic structure in which classical addition and multiplication are replaced by ⊕ and ⊗, where a ⊕ b = max{a, b}, a ⊗ b = min{a, b}. The notation A ⊗ x = b represents an interval system of linear equations, where A = [A,A], b = [b, b] are given interval matrix and interval vector, respectively, and a solution is from a given interval vector x = [x, x]. We define six types of solvability of max-min interval systems with bounded solution and give necessary and sufficient conditions for them. Source

Vascak J.,Technical University of Kosice

Purpose: Conventional rule-based systems are insufficient for description of complex dynamic systems requiring nontrivial decision procedures. Fuzzy cognitive maps seem to be convenient to overcome these limitations. However, they lack ability of self-learning and therefore some adaptation approaches are needed. The purpose of this paper is both to show the use of fuzzy cognitive maps for such systems and to present migration algorithms as convenient adaptation means. Design/methodology/approach: Some problems of a complex dynamic system description by knowledge-based means are discussed. Fuzzy cognitive maps are presented as a possible way to solve these problems followed by description of migration algorithms as their adaptation means. Their use is clarified on an example of the so-called parking problem based on path planning using a graph search algorithm and a traffic simulation system. Findings: After series of simulations the reality of the proposed system and selected methods with their modifications was proved. It has shown the robustness of the presented solution under circumstances of uncertainty, too. Research limitations/implications: The paper points to stability investigation of the proposed approach introducing uncertainties into the traffic simulation system to take into account, e.g. unexpected events. Further, a possibility of developing a linguistic information retrieval system is mentioned. Practical implications: The proposed approach can find various implementations not only in planning tasks but also in robotic navigation and multi-agent applications in general. In addition, it suggests possibilities of knowledge-based systems, directly using human-like approaches, to areas of decision making under uncertainties and contradictories. Originality/value: An new modification of migration algorithms for adaptation of parameters for fuzzy cognitive maps is introduced and compared to other known self-learning methods. Further, the concept of a traffic simulation system for path planning is presented. © Emerald Group Publishing Limited. Source

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