In the first scenario, the single input, single output
(SISO) performance is evaluated. Here only the first
input and output of the process are considered, signifi-
cantly simplifying the control problem thereof. In the
second scenario, all inputs and outputs are considered,
resulting in a true MIMO problem, commonly found in
most of the more complex processes. In the third scenario,
both of the inputs and only the first output are
considered, resulting in a multiple input, single output
(MISO) problem. This type of problem is common for
processes where the required control forces are such
that multiple actuators are required to provide them.
In the last scenario, only the first input and both outputs
are considered, resulting in a single input, multiple
output (SIMO) problem. These types of problems arise
when the disturbance rejection is required at several