  We propose a realization of a transformation-based acoustic temporal cloak
using an active closed-loop control approach to an equivalent electromagnetic
problem. Unlike the more common spatial cloaks the goal of which is hiding
fixed objects from detection, the goal of the temporal cloak is hiding the
occurrence of events during a finite period of time. In electromagnetic
systems, in which events represent, for example, leakage of signals from
transmission lines or optical fibers, temporal cloaking solutions usually rely
on nonlinear phenomena related to the fibers properties, or on modulating the
properties of the propagation medium itself. In particular, the
transformation-based solution requires modulating the constitutive parameters
of the medium both in space and time. Our control approach is fully linear,
where the required change in the medium parameters is programmed into the
controllers and created by external actuators in real-time. This cloaking
system keeps the physical medium unchanged, and enables to reprogram the
cloaking parameters upon request. We demonstrate our solution in a simulation
of a one-dimensional water channel.
