On zeros and responses of linear regulators and linear observers

In the pole assignment of the single input and output regulator, there is a case where the integrated square output becomes infinite and the response of the output has an infinitely large maximal amplitude when all poles of the closed loop system are assigned to negative infinity in the numerical
s
-plane. This paper deeply investigates this problem from the linear structure point of view and applies the obtained results to the pole specification problem of observers.