Fuzzy temporal rules:: A rule-based approach for fuzzy temporal knowledge representation and reasoning

In this paper a model for the representation and execution of a type of fuzzy control rules that explicitly handle time variable (Fuzzy Temporal Rules) is presented. The model here described permits using temporal references for the occurrence of events. These references are allowed to be described either in an absolute manner or related to occurrence of other events. A complete grammar that formally describes the representation language of the model is presented, together with its semantic counterpart. This knowledge and reasoning representation model is illustrated by means of a number of examples that show the substantial increase in the expresiveness that FTRs exhibit when compared to usual fuzzy control rules.