Try to think of a regulatory system where the parameter to be regulated can be controlled by either a human-in- the-loop control system or a computer-in-the-loop control system. ( We already dealt with a ton of these! But try to come up with an example of you own). Now draw the block diagrams for these two control systems. Remember, the inputs for both of the block diagrams have to be the same ( as well as the outputs) - you are regulating the same parameter but in different ways