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Trajectory Data Analyses for Pedestrian Space-time Activity Study
Published on: February 25, 2013
Reducing weighted ensemble variance with optimal trajectory management
Won Hee Ryu1, John D Russo1, Mats S Johnson2
1Biomedical Engineering, Oregon Health and Science University, Portland, Oregon 97239, USA.
The Journal of Chemical Physics
|March 3, 2026
Summary
Optimal parameterization of the weighted ensemble (WE) method enhances the accuracy of biophysical process kinetics. This strategy reduces variance in mean first-passage time (MFPT) estimates for molecular folding and unfolding simulations.
Area of Science:
- Computational chemistry
- Biophysics
- Statistical mechanics
Background:
- Weighted ensemble (WE) is a path-sampling method for estimating mean first-passage times (MFPTs).
- WE simulations can suffer from high variance in MFPT estimates due to suboptimal parameter choices for trajectory pruning and replication.
- Previous work introduced an optimal WE parameterization strategy for low-dimensional systems.
Purpose of the Study:
- To apply and evaluate an optimal WE parameterization strategy to high-dimensional molecular models.
- To assess the strategy's effectiveness in improving the accuracy and reliability of MFPT estimates for biophysical processes.
- To investigate the impact of parameterization on Trp-cage and NTL9 folding/unfolding simulations.
Main Methods:
- Application of an optimal WE parameterization strategy based on local MFPT estimates.
- Simulation of synthetic and atomistic molecular dynamics (MD) models for Trp-cage and NTL9.
- Estimation of folding/unfolding MFPTs using WE in various friction regimes.
Main Results:
- The optimal parameterization strategy was applied to high-dimensional molecular models.
- Reduced variance in MFPT estimates was observed in three out of four systems studied.
- A significant improvement in MFPT estimation was achieved for a challenging atomistic NTL9 folding system.
Conclusions:
- The optimal WE parameterization strategy enhances the accuracy and reliability of kinetic estimates for biophysical processes.
- This approach is effective for complex, high-dimensional molecular systems.
- The strategy offers a robust method for improving WE simulation outcomes in biophysics.
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