  Motivated by the safety and security issues related to cyber-physical systems
with potentially multi-rate, delayed, and nonuniformly sampled measurements, we
investigate the attack detection and identification using the lifted system
model in this paper. Attack detectability and identifiability based on the
lifted system model are formally defined and rigorously characterized in a
novel approach. The method of checking detectability is discussed, and a
residual design problem for attack detection is formulated in a general way.
For attack identification, we define and characterize it by generalizing the
concept of mode discernibility for switched systems, and a method for
identifying the attack is discussed based on the theoretical analysis. An
illustrative example of an unmanned aircraft system (UAS) is provided to
validate the main results.
