A novel and unified approach is proposed in sieve estimation to tackle the issue of unbounded support of variables in nonparametric regression models. The model em- braces time trend and both stationary and nonstationary variables that are allowed to be correlated. This approach is introduced...

This paper considers nonparametric additive models that have a deterministic time trend and both stationary and integrated variables as components. The diverse nature of the regressors caters for applications in a variety of settings. In addition, we extend the analysis to allow the stationary...

In this paper, we propose three new predictive models: the multi-step nonparametric predictive regression model and the multi-step additive predictive regression model, in which the predictive variables are locally stationary time series; and the multi-step time-varying coefficient predictive...