Exponential squared loss based robust variable selection of AR models

Time series analysis is widely used in the fields of economics, ecology and medicine. Robust variable selection procedures through penalized regression have been gaining increased attention. In our work, a robust penalized regression estimator based on exponential squared loss for autoregressive (AR) models is proposed and discussed. The objective model with adaptive Lasso penalty realizes variable selection and parameter estimation simultaneously. Under some regular conditions, we establish the asymptotic and “Oracle” properties of the proposed estimator. In particular, the induced non-convex and non-differentiable mathematical programming problem offers challenges for solving algorithms. To solve this problem efficiently, we specially design a block coordinate descent (BCD) algorithm equipped with concave-convex process (CCCP) and provide a convergence guarantee. Numerical simulation studies are carried out to show that the proposed method is particularly robust and applicable compared with some recent methods when there are different types of noise or different intensity of noise. Furthermore, an application on a dataset of daily minimum temperature in Melbourne over 1981-1990 is performed.