Because the characteristics of the disturbance are
known a priori, it is feasible to include this information
in the control design. In IDC and FSCF methods, the
disturbance was modeled either as filtered white noise
or notch-filtered process output. In the DOFC method,
the disturbance is modeled explicitly as an autonomous
sinusoidal signal, with the possibility for nonzero mean
value also taken into account through the introduction
of additional bias states. Essentially, the method shares
the same IMC-like structure as the first three designs.