A method for dependency matrix combination based on port connection relationship

Dependency matrix is a kind of description form of the dependency relationships between the faults and tests in a UUT (Unit Under Test). Testability analysis, testability prediction and fault diagnosis can be accomplished on the basis of dependency matrix. The traditional method of acquiring dependency matrix is to search the signal flow of the UUT´s dependency graphical model. The difficulties in integrating the models together and the exponentially growing workload to search the signal flow are two major disadvantages of the traditional method. To overcome these disadvantages, a new method for dependency matrix combination based on port connection relationship is proposed. Definitions of port-extended dependency matrix and global port connection matrix are given. The principle of dependency matrix combination method is analyzed with the definitions of the two matrixes above given. The generation algorithms of a port-extended dependency matrix and a global port connection matrix are studied. Based on the port-extended dependency and the global port connection matrix, the algorithm flow of the dependency matrix combination method is given. A case of an avionic system is given and the above method is applied. The result shows that the method is feasible and effective.