A Class Of Processing Time Uncertainty

The temporal knowledge is of certain uncertainty, making its expression and processing has certain difficulty. Because of the universal existence of conflict relations, a series of temporal uncertainty problems associated with conflict events arise in the complicated application system modeling process. However, the existing methods of temporal knowledge processing are not capable of handling quantitative temporal uncertainties in conflict and, therefore, can not deal with the specific needs in various complicated application system modeling.On the basis of existing studies on temporal uncertainty, this paper gives prominence to temporal uncertainty associated with conflict events exists in complicated system modeling. Combining with possibility theory, we propose an uncertain temporal knowledge expression and analysis method by introducing fuzzy time interval and computation of possibility to do quantitative analysis for temporal uncertainty based on system modeling. The method represents the uncertain temporal knowledge with fuzzy time interval, implements the reasoning through computation of fuzzy time functions, and analyzes quantitatively temporal uncertainty in conflict events based on possibility theory. A train group operation instance in RITS shows that the method can effectively analyze the temporal uncertainty in train group operation and adjustment and capable of dealing with temporal uncertainty associated with conflict events, and therefore, overcome the shortcomings of existing methods. Compared with existing methods, this method has some outstanding characteristics such as quantitative analysis for conflict, easy to calculate and simple reasoning process.The Extended Fuzzy-Timing Petri net described in this paper and the corresponding reasoning method can deal with quantitatively the temporal uncertainty associated with conflict events in complicated system. It can be used to study not only train group operation and adjustment but also other transport system, communication, network, industry and mining machine control and so on.