Epk 2005

One of the main features of Event driven Process Chains (EPCs) is the non-local semantics of the OR-join and the XOR-join connectors. Simulating this non-local semantics faithfully and efficiently is still a challenging problem. A year ago, we have shown that the semantics of moderately sized EPCs can be calculated in reasonable time by using techniques from symbolic model checking. For larger EPCs, however, this method still takes too long for practical use. In this paper, we introduce and discuss a new technique for calculating the semantics of EPCs: We combine an explicitly forward construction of the transition system with a backward marking algorithm for checking the non-local constraints. Though this method does not always provide a result, it works for most practical examples and, in most cases, it is much faster than the symbolic algorithm. Basically, the computation time is linear in the size of the resulting transition system. The algorithm works for large EPCs as long as the resulting transition systems are small (where transition systems with millions of states and transitions are still considered to be small), which is true for many practical EPCs.