An approach to performance equivalent simplification of sequent and parallel structures of DSPN

State space explosion of DSPN and inexistence of homogeneous Markov chain are key problems of DSPN models analysis. Based on the analysis of the definition of DSPN and the characters of different transitions, a method to performance equivalent simplification of sequent and parallel structures of DSPN is proposed. Based on this method, an arbitrary sequent or parallel structure with arbitrary number immediate, deterministic and exponential transitions, could be simplified into a sequent structure with a deterministic transition and an exponential transition, or be simplified into a single exponential transition. And the time characters of the simplified structure are reserved. The analysis result of an example shows that, the method is effective in reducing the state space of the DSPN models with sequent or parallel structures. And the method could resolve the inexistence of homogeneous Markov for some DSPN models.