The makers of the tracking systems say the software can determine the viewer's gender, approximate age range and, in some cases, ethnicity - and can change the ads accordingly.

In track simulation, the corresponding earth equivalent radius of a track in a specific range is approximate to the earth curvature radius of the latitudinal location of the target.

The results show that the reduced bilinear model developed can approximate the reactor dynamics more accurately than the linear one over a much wider range around the operating state.