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Search Results: 1 - 10 of 294 matches for " Dusan Kocur "
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Performance Evaluation of M-APSK Modulation in the Nonlinearly Distorted LTE Uplink
Juraj Gazda,Denis Dupak,Dusan Kocur
Information Technology Journal , 2012,
Abstract: Single Carrier Frequency Division Multiple Access (SC-FDMA) scheme has been considered to be promising technology for the uplink of the 4G mobile communication systems. In spite of the precoding application, SC-FDMA signal using the standard M-QAM base-band modulation scheme still suffers from its high envelope fluctuation resulting in a nonlinear distortion of the transmitted signals due to the transmitter High Power Amplifier (HPA). In order to improve the SC-FDMA performance, the M-ary Amplitude Phase Shift Keying (M-APSK) is proposed as a base-band modulation scheme for SC-FDMA in this study. The application of M-APSK for SC-FDMA has been motivated by its high spectrum efficiency and at the same, time smaller signal fluctuation of the M-APSK signals than that of M-QAM. The performance properties of M-APSK and M-QAM based SC-FDMA transmission scheme will be illustrated using numerical results. The obtained results will show very clearly that the M-APSK based SC-FDMA transmission can provide the preferable performance to M-QAM SC-FDMA if the nonlinear operation of HPA has to be assumed.
Imaging Method: An Efficient Algorithm for Moving Target Tracking by UWB Radar
Dusan Kocur,Jan Gamec,Maria ?vecová,Maria Gamcová
Acta Polytechnica Hungarica , 2010,
Abstract: This paper presents the imaging method applied for moving target tracking by amultistatic ultra-wideband radar system. The imaging method consists of such signalprocessing phases as raw radar data pre-processing, background subtraction, the fusion ofthe data obtained by the particular receiving channels of a radar, detection, localizationand the tracking itself. In this paper, the particular phases of the imaging method aredescribed. Firstly, the theoretical base of the particular phases is denoted and then anoverview of the signal processing methods which can be applied within correspondingphase is given. Here, we will also outline that a signal cross-talk, exponential averaging,2D double-stage (N,k) detector, a target gravity center estimation and a low-complexnonlinear two-stage tracking filter can be used within the mentioned radar signalprocessing phases as convenient signal processing methods. The good performance of theimaging method presented in this contribution is illustrated by processing signals obtainedby the ultra-wideband radar for a scenario represented by through wall tracking of a singlemoving target.
Identification and Modelling of Linear Dynamic Systems
Stanislav Kocur
Advances in Electrical and Electronic Engineering , 2006,
Abstract: System identification and modelling are very important parts of system control theory. System control is only as good as good is created model of system. So this article deals with identification and modelling problems. There are simple classification and evolution of identification methods, and then the modelling problem is described. Rest of paper is devoted to two most known and used models of linear dynamic systems.
What’s new at the back of the eye?
Ivo Kocur
Community Eye Health Journal , 2006,
Abstract: The changing demographic pattern of visual impairment VISION 2020 and the prevention of visual impairment are moving into the political and public spotlight. Recent WHO discussions on the growing incidence of chronic, age-related, non-communicable diseases indicate that visual health and its preservation are now receiving attention. Recent publications illustrate the changing demographic pattern of visual impairment, implications for public health and possible interventions to control sight-threatening conditions. Both The State of the World’s Sight, VISION 2020: the Right to Sight, 1999-2005,1 published jointly by WHO and the International Agency for the Prevention of Blindness (IAPB), and an article in the World Health Bulletin, November 2004,2 illustrate these trends.
Compensation of Wall Effect for Through Wall Tracking of Moving Targets
J. Rovnakova,D. Kocur
Radioengineering , 2009,
Abstract: Through wall tracking of moving targets is of interest for rescue, surveillance and security operations. A useful method applies an ultra-wideband radar approach for this purpose since electromagnetic waves in the lower GHz- range penetrate most common building materials, such as bricks, wood, dry walls, concrete and reinforced concrete. However in consequence of a wall effect, estimated target track can be considerably spatially shifted and distorted. In the paper, two different methods for compensation of this ef- fect are described. Their effectiveness is evaluated at syn- thetic as well as real radar data. Obtained results prove that proposed novel approach reach the best outcomes.
The Machiavellianism and manipulation tactics used by patients with borderline personality disorder in everyday life and in therapy
Mandal, Eugenia,Kocur, Dagna
Psychiatria Polska , 2013,
Abstract: Aim. The aim of the researches was to inspect the relation between borderline personality and Machiavellianism as well as the tendency to apply various manipulation tactics in everyday life and in therapy.Method. The test used an original/ authors’ survey for testing the tendency to employ manipulation tactics as well as a MACH-IV questionnaire (Christie, Geis, 1970) for measuring Machiavellianism. The studied group included 30 patients with diagnosed BPD, 37 therapists and 30 persons in the control group.Results. No differences were noted in the general indicator of Machiavellianism; however, the patients scored lower on the Tactics scale than people from the control group. Patients preferred employing the tactics of taking offense, lying and begging in everyday life. Compared to people from the control group, patients presented a larger tendency to employ tactics of begging, threatening and threatening to break off a close relationship, and a lower tendency to employ seduction. According to therapists, during the therapy patients most often resorted to lying and arousing guilt. Therapists assessed the patients’ tendency to employ manipulation tactics higher than the patients themselves.
Time-Frequency Analysis of Signals Generated by Rotating Machines
D. Kocur,R. Zetik
Radioengineering , 1999,
Abstract: This contribution is devoted to the higher order time-frequency analyses of signals. Firstly, time-frequency representations of higher order (TFRHO) are defined. Then L-Wigner distribution (LWD) is given as a special case of TFRHO. Basic properties of LWD are illustrated based on the analysis of mono-component and multi-component synthetic signals and acoustical signals generated by rotating machine. The obtained results confirm usefulness of LWD application for the purpose of rotating machine condition monitoring.
Chua's Circuit in Spread Spectrum Communication Systems
P. Galajda,D. Kocur
Radioengineering , 2002,
Abstract: Communication system via chaotic modulations is demonstrated. Itcontains the well-known chaotic circuits as its basic elements - Chua'scircuits. The proposed system has some standard properties of spreadspectrum communication. The following advantage is found insimulations: a) Transmitted signals have broad spectra. b) Securecommunications are possible in the sense that the better parametermatching is required in order to recover the signal. c) The circuitstructure of the communication system is most simple and communicationsystems are easily built at a small outlay. Finally computersimulations are given to examine the validity of this system.
Fast Tracking RLS Adaptation Algorithms of the Second-Order Volterra Digital Filters
J. Vasko,D. Kocur
Radioengineering , 1995,
Abstract: Two new fast tracking exponentially weighted conventional recursive least-squares (RLS) algorithms of adaptation of the adaptive Volterra filters (AVF) for time-varying systems are presented. The new algorithms are based on a modification of a priciple of variable forgetting factor with unity zone [1]. Their additional computational complexity due to the forgetting factor adaptation is negligible compared to that of conventional RLS algorithms. The performance properties of the proposed algorithms are verified via computer experiments.
Polyspectral Analysis of Signals: An Introduction
D. Kocur,R. Stanko
Radioengineering , 1998,
Abstract: In this paper, basic terms of the higher order spectrum theory as moments and cumulants of random variables and stationary random processes as well as cumulant and moment spectra are introduced. A part of this paper is devoted to bispectrum estimators. The objective of this paper is also description of bispectrum application for quadratic phase coupling detection.
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