This paper presents a duration dependent model for analyzing the evolution of credit ratings. It considers the backward recurrence process to tackle the time of permanence problem in the rating classes. In this way it is possible to manage the duration effects, which represent one of the most...

We propose a statistical approach to tornadoes modeling for predicting and simulating occurrences of tornadoes and accumulated cost distributions over a time interval. This is achieved by modeling the tornadoes intensity, measured with the Fujita scale, as a stochastic process. Since the Fujita...