In this paper, we consider a new channel sounding scheme for opportunistic scheduling with the use of reduced channel information in the uplink of orthogonal frequency division multiplexing (OFDM)-based wireless systems. To reduce signaling overhead for the sounding, we propose a two step channel sounding process considering the correlation characteristic in the time and frequency domain; calle...

The existence of a strong internal magnetic field allows probing of the interior through both long term changes of and short period fluctuations in that magnetic field. Venus, while Earth's twin in many ways, lacks such a strong intrinsic magnetic field, but perhaps short period fluctuations can still be used to probe the electrical conductivity of the interior. Toward the end of the Venus Expr...

EM sounding formally encompasses both propagative (high-frequency) and inductive (low-frequency) methods. Orbital, surface-penetrating radars have been shown to be effective to depths of kilometers on the Moon and in icy parts of Mars, but have been ineffective over the most of Mars’ silicate surface. Fixed, surface-based radars will likely improve penetration to no more than several hundred me...

[1] Six different geophysical investigations, (1) ground-penetrating radar, (2) DC resistivity sounding, (3) seismic refraction, (4) very low frequency (VHF) electromagnetic, (5) helicopter borne electromagnetic (HEM), and (6) transient electromagnetic (TEM) techniques, were employed to obtain information on the ice body properties of pingos near Fairbanks, Alaska. The surface nuclear magnetic ...

Ionospheric disturbance was observed in ionograms at Kazan, Russia (55.85◦N, 48.81E), associated with the M8.8 Chile earthquake in 2010 (35.91◦S, 72.73W). The disturbance was caused by infrasound waves that were launched by seismic Rayleigh waves propagating over 15,000 km along Earth’s surface from the epicenter. This distance was extremely large compared with the detection limit of similar io...

In this paper we present a brief look at some of the knowledge-based processes used in generatii~g referring expressions in the natural language advisory system WlSBER. Although WISBER is fully capable of exploiting syntactic information to generate contextually appropriate references, the work described here concentrates on the use of conceptual and contingent knowledge about objects in the do...

On 30.14 March 1997 we observed the EUV spectrum of the bright comet C/1995 O1 (Hale-Bopp) at the time of its perihelion, using our EUVS sounding rocket tele-scope/spectrometer. The spectra reveal the presence H Ly β, O + , and, most notably, Argon. Modelling of the retrieved Ar production rates indicates that comet Hale-Bopp is enriched in Ar relative to cosmogonic expectations. This in turn i...