“…Though a constant Lyapunov function can greatly facilitate the analysis and synthesis, the results obtained within time-invariant framework can be somewhat conservative. For this reason, some recent efforts have been made towards the construction of nonquadratic Lyapunov functions that may lead to LMIs or bilinear matrix inequalities (BMIs), see, e.g., Kapila et al [10] for a Lure-Postnikov type Lyapunov function, and Mulder and Kothare [12] and Johansson and Rantzer [9] for the type of piecewise quadratic Lyapunov functions. Some recent works provided novel ideas in constructing Lyapunov functions for saturated systems, see, e.g., Hu et al [8] for a combined quadratic function method consisting of both quadratic and nonquadratic Lyapunov functions, and Lin and Saberi [11] for a parametric Lyapunov equation approach.…”