The variation of R for ER in the case of before and after PR optimization with different RP, where N = 200. (a) The variation of R when RP = 0, (b) the variation of R when RP = 1, (c) the variation of R when RP = 2, (d) the variation of R when RP = 3, and (e) the variation of R when RP = 4. |