This paper offers a new method for estimation and forecasting of the linear and nonlinear time series when the stationarity assumption is violated. Our general local parametric approach particularly applies to general varying-coefficient parametric models, such as AR or GARCH, whose coefficients...

Implied trinomial trees (ITTs) present an analogous extension of trinomial trees proposed by Derman, Kani, and Chriss (1996). Like their binomial counterparts, they can fit the market volatility smile and actually converge to the same continuous limit as binomial trees. In addition, they allow...

Most dimension reduction methods based on nonparametric smoothing are highly sensitive to outliers and to data coming from heavy-tailed distributions. We show that the recently proposed methods by Xia et al. (2002) can be made robust in such a way that preserves all advantages of the original...