A method of transition conflict resolving in hierarchical control

The paper concerns the problem of automatic solving of transition conflicts in hierarchical concurrent state machines (also known as UML state machine). Preparing by the designer a formal specification of a behaviour free from conflicts can be very complex. In this paper, it is proposed a method for solving conflicts through transition predicates modification. Partially specified predicates are transformed into a symbolic Boolean space, whose points code all possible valuations of transition predicates. Next, points of the space are logically multiplied by functions which represent all valuations under partial specifications. The result of this operation contains all possible collections of predicates, which under given partial specification make that the original diagram is conflict free.