Structural identifiability of delayed singular systems

In this paper we derive a condition for a delayed singular system to be a priori structurally globally identifiable with input-state data. At first an identifiability condition is given for a singular system with input delays. We show that identifiability of delayed singular system is related with its weak S controllability. Then structural identifiability condition for delayed singular system is derived under some assumptions. Finally we extend these results to matching problems of bipartite graphs for a special case, where entries of its system matrices are either fixed zeros or free parameters, by graph theoretic approach.