An Efficient Explicit-time Description Method for Timed Model Checking

Hao Wang
(Centre for Logic and Information,St. Francis Xavier University,Canada)
Wendy MacCaull
(Centre for Logic and Information,St. Francis Xavier University,Canada)

Timed model checking, the method to formally verify real-time systems, is attracting increasing attention from both the model checking community and the real-time community. Explicit-time description methods verify real-time systems using general model constructs found in standard un-timed model checkers. Lamport proposed an explicit-time description method using a clock-ticking process (Tick) to simulate the passage of time together with a group of global variables to model time requirements. Two methods, the Sync-based Explicit-time Description Method using rendezvous synchronization steps and the Semaphore-based Explicit-time Description Method using only one global variable were proposed; they both achieve better modularity than Lamport's method in modeling the real-time systems. In contrast to timed automata based model checkers like UPPAAL, explicit-time description methods can access and store the current time instant for future calculations necessary for many real-time systems, especially those with pre-emptive scheduling. However, the Tick process in the above three methods increments the time by one unit in each tick; the state spaces therefore grow relatively fast as the time parameters increase, a problem when the system's time period is relatively long. In this paper, we propose a more efficient method which enables the Tick process to leap multiple time units in one tick. Preliminary experimental results in a high performance computing environment show that this new method significantly reduces the state space and improves both the time and memory efficiency.

In Lubos Brim and Jaco van de Pol: Proceedings 8th International Workshop on Parallel and Distributed Methods in verifiCation (PDMC 2009), Eindhoven, The Netherlands, 4th November 2009, Electronic Proceedings in Theoretical Computer Science 14, pp. 77–91.
Published: 15th December 2009.

ArXived at: bibtex PDF

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