Kronos 8,10,7,11,20,16,4,3,9] is a software tool aiming at assisting designers of real-time systems to develop projects meeting the speci ed requirements.One major objective of Kronos is to provide a veri cation engine to be integrated into design environments for real-time systems in a wide range of application areas. Real-time communication protocols 8,10], timed asynchronous circuits 16,4], and hybrid systems 18,10] are some examples of application domains where Kronos has already been used.Kronos has been also used in analyzing real-time systems modeled in several other process description formalisms, such as Atp 17], Aorta 5], Et-lotos 8], and T-argos 15]. On the other direction, the tool itself provides an interface to untimed formalisms such as labeled-transition systems (LTS) which has been used to exploit untimed veri cation techniques 20].
Theoretical backgroundThe system-description language of Kronos is the model of timed automata 2], which are communicating nite-state machines extended with continuous realvalued variables (clocks) used to measure time delays. Usually a system is modeled as a network of automata. Communication is achieved by label synchronization a la CCS or CSP (binary or n-ary rendez-vous), or shared variables (of bounded integer or enumeration type).System requirements can be speci ed in Kronos using a variety of formalisms, such as the real-time logic Tctl 1,14], timed B uchi automata, or ? Kronos is developed at Verimag, a joint laboratory of UJF, Ensimag and CNRS.
