“…Stochastic resonance was originally proposed by Benzi and his coworkers in 1981 to interpret the periodic recurrences of the earth's ice ages [1], which has attracted lots of attention now and got its potential application in a wide range, for instance, in paleoclimatology [2], electronic circuits [3], lasers [4], chemical systems [5], biological systems [6] and so on. Consequently, great efforts have been devoted to it and many results have been reported [7][8][9][10][11][12][13][14][15][16][17][18][19]. To quantify the onset of stochastic resonance, several approaches (or indicators) have been suggested, such as signal-to-noise ratio (SNR), Fokker-Planck description, linear-response theory and residence-time distributions.…”