Parameter Estimation in Stochastic Differential Equations via Wiener Chaos Expansion and Stochastic Gradient Descent
For researchers in stochastic modeling and inverse problems, this work provides a computationally efficient alternative to traditional MCMC/MLE methods, though the novelty is incremental as it combines existing techniques.
This paper tackles parameter estimation in stochastic differential equations by minimizing a regularized discrepancy functional via stochastic gradient descent, using Wiener chaos expansion to convert the stochastic problem into a deterministic optimization. The method achieves accurate parameter recovery from discrete, noisy observations, offering a paradigm shift in efficient stochastic modeling.
This study addresses the inverse problem of parameter estimation for Stochastic Differential Equations (SDEs) by minimizing a regularized discrepancy functional via Stochastic Gradient Descent (SGD). To achieve computational efficiency, we leverage the Wiener Chaos Expansion (WCE), a spectral decomposition technique that projects the stochastic solution onto an orthogonal basis of Hermite polynomials. This transformation effectively maps the stochastic dynamics into a hierarchical system of deterministic functions, termed the \textit{propagator}. By reducing the stochastic inference task to a deterministic optimization problem, our framework circumvents the heavy computational burden and sampling requirements of traditional simulation-based methods like MCMC or MLE. The robustness and scalability of the proposed approach are demonstrated through numerical experiments on various non-linear SDEs, including models for individual biological growth. Results show that the WCE-SGD framework provides accurate parameter recovery even from discrete, noisy observations, offering a significant paradigm shift in the efficient modeling of complex stochastic systems.