Abstract Spectral analysis characterises oscillatory time series behaviours such as cycles, but accurate estimation requires Hair Mask reasonable numbers of observations.At the time of writing, COVID-19 time series for many countries are short: pre- and post-lockdown series are shorter still.Accurate estimation of potentially interesting cycles see
Risk assessment during emission of toxic chemicals at railway transport is the problem of great scientific interest.To make such assessment we need special computer models.At present, in Ukraine,we have lack of such models.The authors present numerical models for territorial risk assessment in case of organized emissionsat railway transport (for ex
This paper investigates the performance of using multiple intelligent reflecting surface (IRS)-assisted communication as compared to the hybrid approach.We demonstrate that for practical scenarios with a limited amount of radiated power, the performance can be significantly enhanced by increasing numbers of IRS.Upper bounds are derived for multiple