On the Impact of Monte Carlo Statistical Uncertainty on Surrogate-based Design Optimization

Fuente: arXiv
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Auteurs principaux: Erdem, Omer F., Broughton, David P., Svoboda, Josef, Huang, Chengkun, Radaideh, Majdi I.
Format: Preprint
Publié: 2025
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author Erdem, Omer F.
Broughton, David P.
Svoboda, Josef
Huang, Chengkun
Radaideh, Majdi I.
author_facet Erdem, Omer F.
Broughton, David P.
Svoboda, Josef
Huang, Chengkun
Radaideh, Majdi I.
contents In multi-objective design tasks, the computational cost increases rapidly when high-fidelity simulations are used to evaluate objective functions. Surrogate models help mitigate this cost by approximating the simulation output, simplifying the design process. However, under high uncertainty, surrogate models trained on noisy data can produce inaccurate predictions, as their performance depends heavily on the quality of training data. This study investigates the impact of data uncertainty on two multi-objective design problems modelled using Monte Carlo transport simulations: a neutron moderator and an ion-to-neutron converter. For each, a grid search was performed using five different tally uncertainty levels to generate training data for neural network surrogate models. These models were then optimized using NSGA-III. The recovered Pareto-fronts were analyzed across uncertainty levels, and the impact of training data quality on optimization outcomes was quantified. Average simulation times were also compared to evaluate the trade-off between accuracy and computational cost. Results show that the influence of simulation uncertainty is strongly problem-dependent. In the neutron moderator case, higher uncertainties led to exaggerated objective sensitivities and distorted Pareto-fronts, reducing normalized hypervolume. In contrast, the ion-to-neutron converter task was less affected--low-fidelity simulations produced results similar to those from high-fidelity data. These findings suggest that a fixed-fidelity approach is not optimal. Surrogate models can still recover the Pareto-front under noisy conditions, and multi-fidelity studies can help identify the appropriate uncertainty level for each problem, enabling better trade-offs between computational efficiency and optimization accuracy.
format Preprint
id arxiv_https___arxiv_org_abs_2506_00018
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle On the Impact of Monte Carlo Statistical Uncertainty on Surrogate-based Design Optimization
Erdem, Omer F.
Broughton, David P.
Svoboda, Josef
Huang, Chengkun
Radaideh, Majdi I.
Applications
Computational Physics
In multi-objective design tasks, the computational cost increases rapidly when high-fidelity simulations are used to evaluate objective functions. Surrogate models help mitigate this cost by approximating the simulation output, simplifying the design process. However, under high uncertainty, surrogate models trained on noisy data can produce inaccurate predictions, as their performance depends heavily on the quality of training data. This study investigates the impact of data uncertainty on two multi-objective design problems modelled using Monte Carlo transport simulations: a neutron moderator and an ion-to-neutron converter. For each, a grid search was performed using five different tally uncertainty levels to generate training data for neural network surrogate models. These models were then optimized using NSGA-III. The recovered Pareto-fronts were analyzed across uncertainty levels, and the impact of training data quality on optimization outcomes was quantified. Average simulation times were also compared to evaluate the trade-off between accuracy and computational cost. Results show that the influence of simulation uncertainty is strongly problem-dependent. In the neutron moderator case, higher uncertainties led to exaggerated objective sensitivities and distorted Pareto-fronts, reducing normalized hypervolume. In contrast, the ion-to-neutron converter task was less affected--low-fidelity simulations produced results similar to those from high-fidelity data. These findings suggest that a fixed-fidelity approach is not optimal. Surrogate models can still recover the Pareto-front under noisy conditions, and multi-fidelity studies can help identify the appropriate uncertainty level for each problem, enabling better trade-offs between computational efficiency and optimization accuracy.
title On the Impact of Monte Carlo Statistical Uncertainty on Surrogate-based Design Optimization
topic Applications
Computational Physics
url https://arxiv.org/abs/2506.00018