“…Selecting α * = 0.55 yields T u (t) t ≤ 1 2 according to Cond 1 . Given α = 0.5, T * a = 0.8253 has been obtained according to 46th IEEE CDC, New Orleans, USA, Dec. [12][13][14]2007 ThPI27.14 Cond 2 . Thus, according to (21), if the unavailability rate is not more than 1 2 , that is, the total failure time is not more than half of the whole time, and the failure frequency is less than 1 T * a , then system (29) with actuator or controller failure is still exponentially stable with ||x(t)|| ≤ 2.3772e −0.025t ||x 0 || c1 .…”