标识T-网中同步距离的计算

Computation of Synchronic Distance in Marked T-net

同步距离是刻画事件之间同步关系的一个重要的定量分析手段。由于同步距离的求解不仅和网的结构特征有关系,而且和网的初始标识也存在关系,因此到目前为止还没有一个很简洁易行的算法来求解一般Petri网的同步距离。然而,一些特殊的Petri网子类,如标识T-图、标识S-图的同步距离的计算已经有了较简洁的求解方法。对另一个Petri网子类——标识T-网给出了其同步距离的计算方法。标识T-网也可以直接通过网的结构和初始标识分布情况来得到变迁之间的同步距离,不需要考察网系统的运行,这就使得同步距离的求解简单易行。文中给出了相应的求解定理。

Synchronic distance is an important analyzing metric to describe the dependence relationship between two events. Because computation of synchronic distance involves both structure and initial marking of net systems, a simple and feasible algorithm which can get synchronic distance in normal Petri nets doesn＇t have been obtained so far. Howew er computation of synchronic distance in some particular subclass of Petri nets such as marked T-graph and marked S- graph is simple and feasible. Another subclass of Petri net-marked T-net in which solution of synchronic distance is given in this paper. Synchronic distance of marked T-net can be directly obtained according to structure of net systems and distributed situation of initial marking, which make solution of synchronic distance become feasible. Solution theorem of them are given simultaneously in this paper.