[IEEE Eighth ACIS International Conference on Software Engineering, Artificial Intelligence, Networking, and Parallel/Distributed Computing (SNPD 2007) - Qingdao, China (2007.07.30-2007.08.1)] Eighth ACIS International Conference on Software Engineering, Artificial Intelligence, Networking, and Parallel/Distributed Computing (SNPD 2007) - Two Symmetrical Decomposition Methods for Structure-complex Petri Nets and Their Applications