Analysis of fuzzy time interval in the hybrid Petri net model of train operation system

The paper presents a method for calculating fuzzy time interval in the hybrid Petri net model of train operation system. Owing to the system hybrid attributes, hybrid Petri net is used to model the train operation system. In order to quantitatively analyze various uncertainty factors of the system, the theory of probability-possibility transformations is introduced to calculate fuzzy time interval related to the model. We design two experiments which are the simulations of single train and train tracking. The results show that possibility distribution of train´s arrival time can be statistically gained, and then we compute fuzzy time interval based on the theorem of probability-possibility transformations. Compared with existing methods, this method based on hybrid Petri net provides a more reasonable way of analyzing uncertainty factors and improves former methods of temporal reasoning.