“…Those advantages originate in their simplicity, their connection with classical single-input single-output control and in implementation and tuning issues (Conley, 2000), (Yuz and Goodwin, 2003). Nevertheless, that approach to control system design poses several fundamental questions (Sourlas and Manousiousthakis, 1995), (Goodwin et al, 1999), (Salgado and Conley, 2004). Among those questions are, firstly, how to select those measurements that will be used to generate every plant input, i.e., how to pair inputs and outputs, and secondly, once the pairing has been decided, how to synthesize, if possible, a stabilizing controller.…”