National Repository of Grey Literature 12 records found  1 - 10next  jump to record: Search took 0.00 seconds. 
Digisonde measurement
Kouba, Daniel ; Mošna, Zbyšek ; Koucká Knížová, Petra ; Boška, Josef ; Rejfek, Luboš
Ionospheric station in Průhonice currently performs its measurements using Digisonda DPS 4D. The vertical profile of the electron concentration can be measured by ionospheric vertical sounding using Ionosonde and Digisonde. The electron concentration profile shows the location of the layers of the ionosphere, the D, E, F1 and F2 layers, and the electron concentration at a given height. Another way to study the behavior of the ionosphere is to measure Doppler shift in ionospheric plasma. The Průhonická observatory is part of the Digisond World Network. The measured data is immediately automatically sent to the GIRO database (http://ulcar.uml.edu/DIDBase/).
Impact of the troposphere on the inosphere
Koucká Knížová, Petra ; Mošna, Zbyšek ; Potužníková, Kateřina ; Boška, Josef ; Kouba, Daniel
Ionosphere represents weakly ionized plasma that reflects solar and geomagnetic activity and processes\nin the neutral atmosphere. Correlation of long time series of the ionospheric plasma critical frequencies,\nobtained by mean of vertical sounding from European stations, is analysed with respect to latitudinal and\nlongitudinal difference and surface distance of stations. Time series of critical frequencies are highly correlated\nreflecting the dominant solar influence. Correlation coefficients are high not only for raw data and subtracted\nmean courses but for fluctuations around mean as well. At the surface distance exceeding 1000 km and/ or about\n10 degrees of latitudinal difference between stations, the correlation coefficients of fluctuations decrease\nrapidly. Such effect is less visible on the latitudinal dependence, where the correlation coefficients decrease with\nincreasing distance with less pronounced threshold. We explain the existence of the ‘break point’ at 10 degrees\nin longitude and/or 1000 km by the ‘local’ influence of the neutral atmosphere and the wave activity. As a\npossible source of the common influence on scale 1000 km/10 degree we propose tropospheric systems that are\nknown to be an important source of atmospheric waves in a broad period range. Large tropospheric mesoscale\nsystems have typically up to 2000 km in size.
POS systems in cooperatives
Boška, Josef ; Kubálková, Markéta (advisor) ; Kubálek, Tomáš (referee)
This work is devoted to POS systems in Consumer Cooperatives, their contribution to the supply market, practical solutions and use their weaknesses. The theoretical introduction is defined portion, which includes POS systems and their theoretical benefits in a business informatics. Furthermore, the real situation is outlined deployment and use of POS systems in Consumers Cooperatives. The conclusion is demonstrated on a practical example of a possible way of improving the efficiency of utilization of the datamining.
Měření driftů v F-vrstvě ionosféry, první výsledky pro zimu 2006
Kouba, Daniel ; Šauli, Petra ; Boška, Josef ; Santolík, Ondřej
We describe step by step a newly improved method of drift velocity evaluation: (i) height range selection, (ii) Doppler frequency shift value limitation, and (iii) choice of the maximum incidence angle. Our preliminary results describe drift velocity behaviour during quiet geomagnetic conditions for the winter season for station Pruhonice.
Driftová měření pro F-vrstvu ionosféry na stanici Průhonice - sezonní průběhy charakteristik pro klidné dny
Kouba, Daniel ; Šauli, Petra ; Boška, Josef ; Santolík, Ondřej
In the paper we concentrate on the F-region drift-data measured by the ionospheric station Pruhonice (50.0N, 14.6E). We demonstrate application of the skymap points selection method on the data set collected in 2006, during a period of low geomagnetic and solar activity. Using histograms of horizontal and vertical velocity components we found prevailing directions of plasma motion corresponding to specified ranges of velocities. Within the analyzed data we found significant decrease of the daily-maximal horizontal component from winter to summer 2006.
Characterization of the acoustic-gravity waves observed in the electron concentration mesured via vertical ionospheric sounding using wavelet anaysis
Šauli, Petra ; Abry, P. ; Boška, Josef ; Potužníková, Kateřina
Description of the oscillations in the electron concentration in the F region ionosphere using wavelet analysis allows detection of the wave-like structures, that could be „invisible“ for classical spectral analysis. Suitable choice of mother wavelet and sampling period, it is possible to find coherent structures in the wide range of the ionosphere. This aproach allows to improve localiyation of the wavelike structure, find propagation parameters and locate the source region of the propagation.
Ionospheric effects of Solar eclipse 11.8. 1999
Boška, Josef ; Šauli, Petra ; Burešová, Dalia
Ionospheric response to Solar eclipse of 11.8.1999 was observed by ionospheric vertical sounding at Pruhonice observatory. One minute ionograms have been taken to evaluate changes of the main ionospheric characteristics and wave effects during this unique phenomenon.
Wave effects in the electron concentration in the ionospheric F-layer during geomagnetic quiet conditions
Šauli, Petra ; Boška, Josef
The Earth's atmosphere supports wide range of wave like movements so called atmospheric waves. The observed acoustic gravity waves during geomagnetically quiet conditions are dominantly of tropospheric or stratospheric origin.

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