Letna

Košice, Slovakia
Košice, Slovakia
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Repka M.,Institute of Computer Science and Mathematics | Varchola M.,Letna | Drutarovsky M.,Letna
Journal of Electrical Engineering | Year: 2015

In this work, we improved Correlation Power Analysis (CPA) attack against Digital Signature Algorithm (DSA) and its various derivations, such as Elliptic Curve Digital Signature Algorithm (ECDSA). The attack is aimed against integer multiplication with constant secret operand. We demonstrate this improvement on 16-bit integer multiplier in FPGA. The improvement makes it possible to guess more blocks of key, and the improvement also eliminates errors of simulated attacks what is very important when approximating attack success rate and complexity based on simulated attacks. We also discus a possible efficient countermeasure. © 2015 FEI STU.


Broda M.,Letna | Hajduk V.,Letna | Levicky D.,Letna
Proceedings Elmar - International Symposium Electronics in Marine | Year: 2015

Steganography is the process of implanting secret message in a cover data without causing degradation neither to the cover information nor to the secret message implanted in the cover data. Most of the steganographic techniques are applied on images, texts, and protocols. In this paper a novel algorithm of image steganography is proposed to implant a secret text message into a cover image using YCbCr color space model and 2D Haar Discrete Wavelet Transform. In this proposed technique, input text in ASCII code is encrypted by AES what ensures, that the relative letter frequency of a plain text secret message will be disturbed. Proposed technique also solves conversion between color space models RGB and YCbCr in spite of modification in component Cb by the secret message. This step allows extracting of secret message without errors what is a very important characteristic, because change of only one bit causes extracting of different character. Performance of the proposed algorithm has been gauged by the peak signal to noise ratio (PSNR) and mean square error (MSE) for the stego image. © 2015 Croatian Society Electronics in Marine-ELMAR.


Iveta G.,Letna | Jozef B.,Letna
Applied Mechanics and Materials | Year: 2014

In this paper concepts and behaviour of plasticity, hyperelasticity and hyperplasticity are explained and clarified. Description of hardening models and hyperplastic models is provided too. The theoretical overview presented in this paper covers the crucial prerequisite for creating and applying hyperplastic material models into practice, either for simulation purposes or for real world application. © (2014) Trans Tech Publications, Switzerland.


Trebuna F.,Letna | Simcak F.,Letna | Bocko J.,Letna | Pastor M.,Letna | Delyova I.,Letna
EAN 2011: 49th International Scientific Conference on Experimental Stress Analysis | Year: 2011

After more than ten years of operation of casting pedestal the cracks occur in its supporting structure. In the paper is given a procedure for analysis of supporting structure of casting pedestal with the aim to determine reasons of failures and to propose modifications that ensure its future operation. © Tomáš Návrat, Vladimír Fuis, Lubomír Houfek and Miloš Vlk, 2011.


Trebuna F.,Letna | Simcak F.,Letna | Gasinec J.,Institute of Geodesy and Geographical Information Systems | Sarga P.,Letna | Bobovsky Z.,Letna
EAN 2011: 49th International Scientific Conference on Experimental Stress Analysis | Year: 2011

Stop logs of hydraulic power stations are during their operation loaded by dynamic loading. With respect to their long-term operation it is necessary to verify their safe functionality to block watercourses. In the paper is presented stress analysis of stop logs with the aim to verify their functionality as well as determination of critical locations on stop logs for identification of potential failures of welds. © Tomáš Návrat, Vladimír Fuis, Lubomír Houfek and Miloš Vlk, 2011.


Marianna T.,University of P.J. Šafarik | Laputkova G.,University of P.J. Šafarik | Sabo J.,University of P.J. Šafarik | Zivcak J.,Letna
Biomedical Research (India) | Year: 2013

The aim of the study was to evaluate the genotoxic effect of high-frequency electromagnetic field on the human adenocarcinoma cells using HRM analysis. Detecting genetic variations can contribute to the future perspective of anti-tumor strategies combining EMF and anti-cancer drugs. Our data suggest that high-frequency EMF with a frequency of 900 MHz (an input power of 8 W) after 3 h exposure may produce alterations in the melting temperature of DNA of MCF-7 cells from 76.4±0.9°C to 82.6±1.0°C. DNA was extracted from control sample and EMF-exposed MCF-7 cells and MDR1 was sequenced. Comparing the ratio of G+C/A+T on the forward end as well as on the backward end: forward - MCF-7/wt (36.36%/38.67%), MCF-7/EMF (35.30%/39.04%); backward - MCF-7/wt (41.54%/44.62%), MCF-7/EMF (40.13%/44.20%); the decrease of the relative content of G+C/A+T of EMF-exposed MCF-7 cells was observed.


Tarhanicova M.,Letna | Machova K.,Letna | Sincak P.,Letna
Advances in Intelligent Systems and Computing | Year: 2015

Detecting human emotions is an important reserach task in intelligent systems. This paper in the following sections outlines the issue of sentiment analysis with emphasis on recent research direction in emotion detection in text. Firstly, we describe emotions from a psychological point of view. We depict accepted and most used emotional models (categorical, dimensional and appraisal-based). Next, we describe what sentiment analysis is and its interconnection with emotions. We take a closer look at methods used in sentiment analysis taking into consideration emotion detection. Each method will be covered by a few studies. At the end, we propose utilization of emotion detection in the text in human-machine interaction. © Springer International Publishing Switzerland 2015.


Filasova A.,Letna | Hladky V.,Letna | Krokavec D.,Letna
Advances in Intelligent Systems and Computing | Year: 2015

One principle for designing the robust Takagi-Sugeno fuzzy fault detection filter, dedicated to a class of continuous-time nonlinear MIMO system, is treated in this paper. The problem addressed can be designated as an approach exploiting the fuzzy reference model to reflect the problem as an H∞ optimization task, guaranteeing the fault detection performance and the state observer stability. The conditions are outlined in the terms of linear matrix inequalities to possess a stable structure closest to optimal asymptotic properties. © Springer International Publishing Switzerland 2015.

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