“…The true values of unknown parameters are set as A = (10, 28, 8/3) T , B = (35, 28, 3) T and C = (45, 25, 6, 5) T , respectively, which can ensure that the drive systems (25) and (26) operate chaotically, and the response system (27) operates in hyperchaotic state without control. The initial conditions of the systems (25), (26) and (27) are arbitrarily chosen as x(0) = (−10, 0, 37) T , y(0) = (5, −14, −16) T and z(0) = (3.6 − 0.6 j, 0.9 − j, 13, 15) T , separately. The initial values of estimated parameters are randomly selected asÂ(0) = (10, 10, 10) T ,B(0) = (10, 10, 10) T andĈ(0) = (10, 10, 10, 10) T , respectively.…”