Diffusion of electrons in a two-dimensional system with time-dependent random potentials is investigated numerically. The correction to the conductivity due to inelastic scatterings by oscillating potentials is shown to be a universal function of the frequency $\omega$, which is consistent with the weak localization prediction $(e^2)/(3\pi^2 \hbar) log \omega$.
Comment: 4 pages, RevTeX, 3 postscript figures, accepted in J. Phys. Soc. Jpn.(1997)Apr