Figure 5.

Estimation of a broad step-size distribution in the presence of measurement noise; results from one representative simulation. As in Fig. 4, a 2000-point time course was simulated, but in this case it consisted of variable-sized steps. (A) Step-size histogram of the 200 generated steps; the distribution approximates a mixture of Gaussians with means of 20 and 30 nm having standard deviations of 3 nm. (B) Convergence of L with a one-state HMM when the simulated time-course had 3, 7, 10, or 15 nm RMS of added Gaussian noise. The value of L after 1500 iterations was taken to be the maximum value. (C–F) Estimated step-size distributions from data having the indicated noise standard deviations σ. The final estimated step-size distributions c(w) (solid lines) and the distributions obtained after partial convergence, when L was 1 log-unit below its final value (solid bars), are plotted. Note that the continuous distribution in panel A is recovered as spikes in the analyses of panels C–F.