This dissertation consists of three essays on modeling and parameter estimation for covariance non-stationary processes. The first essay considers the non-linear deformation of time scale for G(lambda)-stationary processes developed by Jiang, Gray and Woodward [2006]. After the appropriate...

In this thesis, we extend Bai and Perron's (1998, Econometrica, pp. 47-78) method fordetecting multiple breaks to nonlinear models. To that end, we consider an unstable univariatenonlinear least squares (NLS) model with a limited number of parameter shifts occurring atunknown dates. In our...