Automatic transformation from UML statechart to Petri nets for safety analysis and verification

As a powerful and object-oriented graphical modeling language, Unified Modeling Language (UML) has been introduced into the design and development of safety-critical computer systems. However, UML model is difficult to reflect the concurrency and consistency of constraint rules between objects and impossible to completely demonstrate the dynamic behavior characteristics of a system. Further, it cannot be directly expressed and analyzed by mathematical tools. Petri net modeling technology uses graphical element place and transition to clearly describe the internal interactions of a system. Meanwhile, Petri net has mature mathematical analysis methods. We have proposed to combine these two tools for designing and analyzing a system with a set of transformation rules from UML statecharts to Petri net. In this paper, an automatic conversion tool is introduced. The tool performs the transformation with three steps as follows: (1) Transforming UML model into XML document, which makes information extraction of the UML model become easier. (2) Analyzing semantics of UML model and Petri net model, then designing data structure for transformation, and completing the transformation based on the transformation rules. (3) Analyzing the transformed Petri net model to verify the characteristics of the UML model. The transformation rules and the tools are developed based on a new railway interlocking system.