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The block diagrams of the composite system and the signal flow graphs of the subsystems are the inputs of the software, which topologies are analyzed in the software and analysis results are output into a M-file for Matlab. The transfer function matricex of the subsystems are derived by the Masion rule. The MATLAB's symbolic computation is used in the software to derive the structural controllability and observability according to the structural criterion over F(z).
Liu et al. (Thu,) studied this question.