Search results for " time variation"
showing 2 items of 2 documents
The International Business Cycle in a Changing World: Volatility and the Propagation of Shocks
2003
This paper examines the changing relationships between the G-7 countries through VAR models for the quarterly growth rates, estimated both over sub-periods and using a rolling data window. Six trivariate models are estimated, all of which include the US and a European (E15) aggregate. In relative terms, the conditional volatility of E15 growth has declined more since 1980 than the well-documented decline for the US. The propagation of shocks has also changed, with the volatility and propagation effects separated by applying shocks of pre-1980 magnitude to VARs estimated over various periods. Rolling estimation reveals that E15 has a steadily increasing impact on the US economy over time, wh…
FLUMO: FLexible Underwater MOdem
2019
The last years have seen a growing interest in underwater acoustic communications because of its applications in marine research, oceanography, marine commercial operations, the offshore oil industry and defense. High-speed communication in the underwater acoustic channel has been challenging because of limited bandwidth, extended multipath, refractive properties of the medium, severe fading, rapid time variation and large Doppler shifts. In this paper, we show an implementation of a flexible Software-Defined Acoustic (SDA) underwater modem, where modulation parameters are completely tunable to optimize performance. In particular, we develop the system architecture following two key ideas. …