We study a class of importance sampling methods for stochastic differential equations
(SDEs). A small noise analysis is performed, and the results suggest that a simple
symmetrization procedure can significantly improve the performance of our
importance sampling schemes when the noise is not too large. We demonstrate that
this is indeed the case for a number of linear and nonlinear examples. Potential
applications, e.g., data assimilation, are discussed.
Keywords
importance sampling, stochastic differential equations,
small noise theory, symmetrization, data assimilation