  This paper studies the possibility of detecting and isolating topology
failures (including link failures and node failures) of a networked system from
subsystem measurements, in which subsystems are of fixed high-order linear
dynamics, and the exact interaction weights among them are unknown. We prove
that in such class of networked systems with the same network topologies, the
detectability and isolability of a given topology failure (set) are generic
properties, indicating that it is the network topology that dominates the
property of being detectable or isolable for a failure (set). We first give
algebraic conditions for detectability and isolability of arbitrary parameter
perturbations for a lumped plant, and then derive graph-theoretical necessary
and sufficient conditions for generic detectability and isolability of topology
failures for the networked systems. On the basis of these results, we consider
the problems of deploying the smallest set of sensors for generic detectability
and isolability. We reduce the associated sensor placement problems to the
hitting set problems, which can be effectively solved by greedy algorithms with
guaranteed approximation performances.
