One mole of an ideal gas undergoes two different cyclic processes I and II, as shown in the P-V diagrams below. In cycle I, processes a, b, c and d are isobaric, isothermal, isobaric and isochoric, respectively. In cycle II, processes ${\mathrm{a}}^{\mathrm{\prime }},{\mathrm{b}}^{\mathrm{\prime }},{\mathrm{c}}^{\mathrm{\prime }}\text{ and }{\mathrm{d}}^{\mathrm{\prime }}$are isothermal, isochoric, isobaric and isochoric, respectively. The total work done during cycle I is W_I and that during cycle II is W_II. The ratio W_I/W_II is _______.