directivity

A measure of the performance of an antenna compared to an isotropic antenna; the ratio of the maximum value of radiation intensity to the average radiation intensity.

Anisotropy in the propagation of earthquake waves in the direction of rupture.

Directionality

1991, COSPAR. Plenary Meeting, Jean-Louis Fellous, COSPAR., Global change and relevant space observations: proceedings of Symposium 1 of the COSPAR twenty-eighth Plenary Meeting held in The Hague, the Netherlands, 25 June-6 July 1990, Pergamon For higher degrees, the spatial integration tends to produce a cancellation and a rapid loss of visibility, although less rapidly for velocity measurement than for luminosity measurement, on account of the directivity of the velocity vector.

First we renounced the directivity of the velocity measurement by using a hot point whose size is of order of the wire diameter [4]. Numerical simulations have shown that the probe then measures the velocity modulus [5].