“…Recently, the mechanism of the instability in this CML was clarified by the H ∞ -norm concept, which plays important roles in the robust control theory [Konishi et al, 1999]. Konishi, Kokame and Hirata reported that the decentralized delayed feedback control (DDFC) method can stabilize chaotic behavior in a one-way open CML [Konishi et al, 1998[Konishi et al, , 2000a. Imai et al observed the instability in the electronic CML circuits, and demonstrated the suppression of the instability by the DDFC method [Imai et al, 2002].…”