Study on the simplified interpretative structural modeling method for the directed acyclic graph

Interpretative Structural Modeling method requires calculating the reachability matrix to realize the structural modeling.However the reachability matrix is difficult to get.It is proved that there is no need to calculate the reachability matrix for a Directed Acyclic Graph(DAG).The Simplified Interpretative Structural Modeling method(SISM) for the DAG is proposed and an algorithm is presented.Under some conditions,SISM can be extended to the general Directed Graph.An example based on the SISM is given.