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This paper presents some of the challenges facing the introduction of ultra-wideband (UWB) technology in wireless applications intended for commercial use, summarizes relevant regulatory and standards developments, and addresses potential implications on spectrum management and radio regulations. 相似文献
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Ewa Slominska Hanna Rothkaehl 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2013
The diurnal, seasonal and latitudinal variations of the electron temperature in the Earth‘s topside ionosphere during relatively low solar activity period of 2005 – 2008 are investigated. In order to examine seasonal variations and morphology of the topside ionospheric plasma temperature, CNES micro-satellite DEMETER ISL data are used. Presented study is oriented on the dataset gathered in 2005 and 2008. Within conducted analysis, global maps of electron temperature for months of equinoxes and solstices have been developed. Furthermore, simultaneous studies on two-dimensional time series based on DEMETER measurements and predictions obtained with the IRI-2012 model supply examination of the topside ionosphere during recent deep solar minimum. Comparison with the IRI-2012 model reveals discrepancies between data and prediction, that are especially prominent during the periods of very low solar activity. 相似文献
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