Improvement method for testability modeling with multiple faults

The existing methods for testability modeling were analyzed, and their shortcomings in project application were given. An improvement method for testability modeling was proposed, based on the signal flow graph method. It supports to set multiple faults for units, and can distinguish between global fault and local fault, while the global fault can be set to propagate along special signal flow of units. The graph definition, the hide attributions definition, the dependency matrix definition of the testability model and the corresponding testability inference method were provided. An improvement algorithm to generate the dependency matrix was presented, based on the high order dependency analysis. An inertial navigation system was taken as an example for modeling. The system testability graph model was built. The improving dependency matrix was generated, and compared with the dependence matrix built with the exiting method. The result shows the feasibility and validity of the improvement method for testability modeling.