Simulation assisted machine learning

TL;DR

This paper introduces SimKern, a novel kernel method that leverages approximate simulations to improve machine learning predictions when system details are partially known, especially with limited training data.

Contribution

The paper proposes using simulation-based kernels in machine learning to incorporate prior system knowledge, enhancing prediction accuracy in data-scarce scenarios.

Findings

Simulation-based kernel outperforms traditional methods with limited data

SimKern effectively captures system behavior across uncertainty scenarios

Applicable across disciplines with approximate simulation models

Abstract

Motivation: In a predictive modeling setting, if sufficient details of the system behavior are known, one can build and use a simulation for making predictions. When sufficient system details are not known, one typically turns to machine learning, which builds a black-box model of the system using a large dataset of input sample features and outputs. We consider a setting which is between these two extremes: some details of the system mechanics are known but not enough for creating simulations that can be used to make high quality predictions. In this context we propose using approximate simulations to build a kernel for use in kernelized machine learning methods, such as support vector machines. The results of multiple simulations (under various uncertainty scenarios) are used to compute similarity measures between every pair of samples: sample pairs are given a high similarity score if they behave similarly under a wide range of simulation parameters. These similarity values, rather than the original high dimensional feature data, are used to build the kernel. Results: We demonstrate and explore the simulation based kernel (SimKern) concept using four synthetic complex systems--three biologically inspired models and one network flow optimization model. We show that, when the number of training samples is small compared to the number of features, the SimKern approach dominates over no-prior-knowledge methods. This approach should be applicable in all disciplines where predictive models are sought and informative yet approximate simulations are available. Availability: The Python SimKern software, the demonstration models (in MATLAB, R), and the datasets are available at https://github.com/davidcraft/SimKern.