Database Reference
In-Depth Information
(a)
(b)
(c) (d)
Figure 9.5 Anonymization steps. (a) Characteristic points. (b) Spatial clusters. (c) Territory
tessellation. (d) Generalized trajectories. (See color plate.)
low average probability. A possible technique is to ensure that for any subtra-
jectory used by the attacker, the reidentification probability is always controlled
below a given threshold 1/
k
; in other words, ensuring the
k
-anonymity property
in the released data set. Here, the notion of
k
-anonymity proposed is based
on the definition of
k-harmful trajectory,
that is, a trajectory occurring in the
database with a frequency less than
k
. Therefore, a trajectory database
D
∗
is
