“…Recently, relying on Finsler lemma, [22] derived more general extended filter design conditions that can contain the conditions from [8,23] as particular cases. Most recently, less conservative robust H ∞ filter design procedures were proposed in [27,28] where memory-based filter schemes were provided via exploiting the past filter states (the past measurements) to compute the current estimation. Note that, the filter design conditions in [8,22,23,27] have a common conservatism, which is the variable structural constraint in linearization of analysis condition.…”