(color online) Optimization algorithm analyses of experimental data under variable forces. Optimized parameters (a) , (b) , (c) , and (d) are shown as functions of the average transition number from experiments of different constant loading rates: 0.01 pN/s, 0.02 pN/s, and 0.005 pN/s. Each point is obtained from eight cycles. By optimizing the whole experiment data of the three different loading rates with about 1164 transition numbers, we obtain the optimized parameters values: s⁻¹, pN, nm, nm (red horizontal lines).