  This study deals with security issues in dynamical networked control systems.
The goal is to establish a unified framework of the attack detection stage,
which includes the four processes of monitoring the system state, making a
decision based on the monitored signal, disconnecting the corrupted subsystem,
and operating the remaining system during restoration. This paper, in
particular, considers a disconnection-aware attack detector design problem.
Traditionally, observer-based attack detectors are designed based on the system
model with a fixed network topology and cannot cope with a change of the
topology caused by disconnection. The disconnection-aware design problem is
mathematically formulated and a solution is proposed in this paper. A numerical
example demonstrates the effectiveness of the proposed detector through an
inverter-based voltage control system in a benchmark model.
