  In the multisensor sequential change detection problem, a disruption occurs
in an environment monitored by multiple sensors. This disruption induces a
change in the observations of an unknown subset of sensors. In the Byzantine
version of this problem, which is the focus of this work, it is further assumed
that the postulated change-point model may be misspecified for an unknown
subset of sensors. The problem then is to detect the change quickly and
reliably, for any possible subset of affected sensors, even if the misspecified
sensors are controlled by an adversary. Given a user-specified upper bound on
the number of compromised sensors, we propose and study three families of
sequential change-detection rules for this problem. These are designed and
evaluated under a generalization of Lorden's criterion, where conditional
expected detection delay and expected time to false alarm are both computed in
the worst-case scenario for the compromised sensors. The first-order asymptotic
performance of these procedures is characterized as the worst-case false alarm
rate goes to 0. The insights from these theoretical results are corroborated by
a simulation study.
