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Bayesian Optimization of Partially Known Systems using Hybrid Models

arXiv:2603.11199v1 Announce Type: new Abstract: Bayesian optimization (BO) has gained attention as an efficient algorithm for black-box optimization of expensive-to-evaluate systems, where the BO algorithm iteratively queries the system and suggests new trials based on a probabilistic model fitted to previous samples. Still, the standard BO loop may require a prohibitively large number of experiments to converge to the optimum, especially for high-dimensional and nonlinear systems. We present a hybrid model-based BO formulation that combines the iterative Bayesian learning of BO with partially known mechanistic physical models. Instead of learning a direct mapping from inputs to the objective, we write all known equations for a physics-based model and infer expressions for variables missing equations using a probabilistic model, in our case, a Gaussian process (GP). The final formulation then includes the GP as a constraint in the hybrid model, thereby allowing other physics-based non

arXiv:2603.11199v1 Announce Type: new Abstract: Bayesian optimization (BO) has gained attention as an efficient algorithm for black-box optimization of expensive-to-evaluate systems, where the BO algorithm iteratively queries the system and suggests new trials based on a probabilistic model fitted to previous samples. Still, the standard BO loop may require a prohibitively large number of experiments to converge to the optimum, especially for high-dimensional and nonlinear systems. We present a hybrid model-based BO formulation that combines the iterative Bayesian learning of BO with partially known mechanistic physical models. Instead of learning a direct mapping from inputs to the objective, we write all known equations for a physics-based model and infer expressions for variables missing equations using a probabilistic model, in our case, a Gaussian process (GP). The final formulation then includes the GP as a constraint in the hybrid model, thereby allowing other physics-based nonlinear and implicit model constraints. This hybrid model formulation yields a constrained, nonlinear stochastic program, which we discretize using the sample-average approximation. In an in-silico optimization of a single-stage distillation, the hybrid BO model based on mass conservation laws yields significantly better designs than a standard BO loop. Furthermore, the hybrid model converges in as few as one iteration, depending on the initial samples, whereas, the standard BO does not converge within 25 for any of the seeds. Overall, the proposed hybrid BO scheme presents a promising optimization method for partially known systems, leveraging the strengths of both mechanistic modeling and data-driven optimization.

Executive Summary

This article introduces a novel Bayesian optimization (BO) approach for tackling partially known systems by combining mechanistic physical models with probabilistic models. The proposed hybrid BO formulation leverages the strengths of both data-driven and model-based optimization methods, yielding significantly better designs and faster convergence. The authors demonstrate the effectiveness of their approach in an in-silico optimization of a single-stage distillation process. By integrating physics-based models with probabilistic constraints, the hybrid BO scheme presents a promising optimization method for complex systems. However, the article raises important questions about the scalability and generalizability of this approach, particularly in the context of high-dimensional systems. Overall, the article makes a significant contribution to the field of optimization and has the potential to impact various fields, including engineering, computer science, and data science.

Key Points

  • Combines mechanistic physical models with probabilistic models for Bayesian optimization
  • Hybrid model formulation yields significantly better designs and faster convergence
  • Incorporates physics-based nonlinear and implicit model constraints

Merits

Strength in leveraging strengths of both data-driven and model-based optimization

The hybrid BO scheme effectively combines the strengths of both mechanistic modeling and data-driven optimization, yielding better designs and faster convergence.

Improved convergence and computational efficiency

The hybrid BO scheme demonstrates significantly faster convergence and improved computational efficiency compared to standard BO loops.

Demerits

Scalability and generalizability limitations

The article raises concerns about the scalability and generalizability of the hybrid BO scheme, particularly in the context of high-dimensional systems.

Dependence on initial samples and prior knowledge

The performance of the hybrid BO scheme is highly dependent on the quality of the initial samples and prior knowledge, which may limit its applicability in real-world scenarios.

Expert Commentary

The article presents a novel and promising approach to Bayesian optimization that leverages the strengths of both mechanistic modeling and data-driven optimization. The hybrid BO scheme demonstrates improved convergence and computational efficiency, making it an attractive option for tackling complex systems. However, the article's limitations and concerns about scalability and generalizability highlight the need for further research and development. In particular, the dependence on initial samples and prior knowledge may limit the applicability of the hybrid BO scheme in real-world scenarios. Nevertheless, the article's findings have significant implications for various fields and have the potential to impact the development of more efficient and effective optimization methods.

Recommendations

  • Future research should focus on addressing the scalability and generalizability limitations of the hybrid BO scheme.
  • The authors should investigate the potential of integrating machine learning and data-driven optimization with the hybrid BO scheme to further improve its performance and applicability.

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