The aero-servo-elastic reduced order model may also be used to identify, for a given feedback controller, the critical value of control input time delay at which the closed-loop aero-servo-elastic system loses its stability.
The proposed study presents an original procedure to evaluate, for two representative passive earplugs, the shortest delay at which human listeners start to perceive two sounds composed of the signal transmitted through the electronic circuit and the passively transmitted signal.
Defined here as the shortest time delay at which at least 20% of the participants noticed an echo, the echo threshold was found to be 8 ms for a bell signal, 16 ms for clean speech and 22 ms for speech corrupted by babble noise when using a shallow earplug fit.
where t 0 is the delay at which I t) is maximum, t 1 t 2 t 3 are the lifetimes and A 1 A 2 A 3 are the weights of each process, respectively.
Three parameters were extracted: (1) the peak correlation coefficient value; (2) the delay at which the peak response occurred; and (3) the halfwidth, which is the width of the cross-covariance function at half its peak value.
The cross-covariance function in the first row shows that neuron A (650 µm) fired before neuron B (800 µm), as indicated by the delay at which the peak activity occurs, and by the function's center of mass.
As a benchmark for echo-threshold, Yin [11] and others [9], [10] have reported the delay at which the lag's response increased to 50% of the response evoked, in each cell, by single sounds.
Defined as the delay at which the lag source begins to influence the owl's behavior [9], [27], and given the delays tested, we can therefore say that the echo-threshold was between 6 and 12 ms, a range consistent with earlier studies [9], [12], [27], [28].
The correlation coefficient is a measure of the peak connection strength and is defined by
On a voxel-wise basis, the delay at which the GLM explained the most variance in that voxel was chosen as the optimal delay.
