关键词: 逻辑数据Petri网, 电子商务系统, 优先级, 时间

Abstract: To solve the problem of token priority in logical Petri nets,the logical data Petri nets with firing rules and its reachability graph were put forward by combining with the advantage of time Petri nets and logic Petri nets.Attributes and arrival time were added for each token.Batch waiting time and duration were added in logic input and output transitions,and duration was added in ordinary transitions.Deletion function and writing function were defined for tokens,and their attributes and arrival time were operated.Moreover,the logical data Petri net model of an electronic commerce system was constructed and the reachability graph was produced based on new states.Time analysis of tokens with different priority and the fairness of user requests were discussed.

Key words: logical data Petri nets, electronic commerce system, priority, time