As an extension of the traditional signed digraph model , layered digraph models make hazard and operability analysis more thorough and systematic , which improves the capability of the expert system in identification of the potential safety hazards in the chemical processes .
In simple introduction content of all directions spreads notional base , be based on actual project project to use background , point out content of all directions sheds the crucial question in running , built gift multidimensional the digraph model of authority .
