  In this paper, we develop a new denial-of-service (DoS) estimator, enabling
defenders to identify duration and frequency parameters of any DoS attacker,
except for three edge cases, exclusively using real-time data. The key
advantage of the estimator lies in its capability to facilitate security
control in a wide range of practical scenarios, even when the attacker's
information is previously unknown. We demonstrate the advantage and application
of our new estimator in the context of two classical control scenarios, namely
consensus of multi-agent systems and impulsive stabilization of nonlinear
systems, for illustration.
