1999/2

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    Time-Frequency Analysis of Signals Generated by Rotating Machines
    (Společnost pro radioelektronické inženýrství, 1999-06) Kocur, D.; Zetik, R.
    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.
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    Interactive Progressive Image Transmission
    (Společnost pro radioelektronické inženýrství, 1999-06) Matus, E.; Levicky, D.
    In progressive image transmission (PIT) the image is transmitted progressively i.e. the low detail image is transmitted as first followed by transmission of detail signals. In our contribution we consider interactivity in the PIT. For example, the observer could specify image regions of highest interest (ROI). In this case, the image transmission should be optimised with respect to the ROI. The definition of objective criterion for interactive PIT is made in this paper as first. The spatial signal decomposition is derived with respect to this criterion. Wavelet transform of spatial components is used. At the end demonstration of proposed algorithm is made.
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    Medium Access Control Protocols for Wireless ATM
    (Společnost pro radioelektronické inženýrství, 1999-06) Dobos, L.; Juhar, J.; Cizmar, A.
    The most crucial issues in the conception of an efficient wireless ATM network are the design of the physical layer, data link layer. Medium Access Control (MAC) protocol and mobility management functions. In this article we focus on MAC protocols, namely on requirements for MAC protocols and on basic concepts of TDMA and CDMA based one. For illustration we consider with Time Division Duplex (TDD) as well as Frequency Division Duplex (FDD).
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    Fuzzy Stack Filters for Image Processing
    (Společnost pro radioelektronické inženýrství, 1999-06) Marchevsky, S.; Stupak, Cs.
    This paper is oriented to filtering by fuzzy stack filter of monochromatic images distorted with impulsive noise. Fuzzy stack filter is acquired by extension of stack filters by means of fuzzy logic. Adding some parameters to this filter, that are adjusted by neural adaptation algorithm, is obtained the new class of filters, so-called fuzzy rank-order filters. This class of filters is compared with other well known filters as stack filters and neural stack filters.
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    The State Space Mystery with Negative Load in Multiple-Valued Logic
    (Společnost pro radioelektronické inženýrství, 1999-06) Galajda, P.; Guzan, M.; Spany, V.
    Switching sequential circuits are an indispensable part of many modern electronic devices, such as memory cells, flip-flop sensors, and many others. Since the invention of flip-flop switching circuits, the study of their dynamic behaviour has played an ever-increasing role. The dynamic properties of sequential circuits can be investigated by means of switching between the system's attractors. In this paper the boundary surfaces are discussed that play a crucial role in the process of switching.