In this paper we study new nonlinear GARCH models mainly designed for time series with highly persistent volatility …. For such series, conventional GARCH models have often proved unsatisfactory because they tend to exaggerate volatility …

This paper offers a new approach for estimation and forecasting of the volatility of financial time series. No … assumption is made about the parametric form of the processes, on the contrary we only suppose that the volatility can be … homogeneity, then the estimate of the volatility can be simply obtained by local averaging. We construct a locally adaptive …

assets, stock market indices, exchange rates etc. A particular problem in investigating multivariate volatility processes … arises from the high dimensionality implied by a simultaneous analysis of variances and covariances. Parametric volatility … to a parametric approach, namely the multivariate GARCH model. -- stochastic volatility model ; adaptive estimation …