Manipulating Clocks in Timed Automata Using PVS

Clock is an important notion in TA (Timed automata). In order to manipulate clock easily and conveniently in TA, a mechanized system called FVofTA (formal verification of timed automata) for specifying and reasoning about real-time systems using TA theory in PVS (prototype verification system) is presented in this paper. This system includes two parts: one for modeling real-time system using TA template in PVS and the other for proof intending for formal verification of real-time system. As one of the important modular of FVofTA, clock manipulations are given in PVS specification and mainly include (1) clock interpretation and clock constraints, (2) clock region equivalence definition and its application, and (3) the clock zone and its DBM (difference-bound matrices) representation. Finally, a case study is investigated with the aid of clock manipulation theories and the results are satisfied.