For optimal scheduling of real-time systems
Computer systems penetrate all aspects of everyday life; sometimes in easily recognisable forms such as personal computers, but also hidden in mobile phones, cars and even washing machines. On the other hand, the development of the associated software is hindered by the limited scientific insight into security and reliability as well as efficiency problems and their solutions. Researchers within the framework of the AMETIST project worked on developing a sound and well-understood theoretical basis to the methods underlying software development. More specifically, substantial progress was made in developing mathematical models of complex, distributed real-time systems that could be used to validate their correct functioning. Project partners at the Aalborg Universitet in Denmark sought to establish timed automata as a unifying model for a large class of systems where timing information plays a crucial role. With the term 'timed automate' they defined the more essential mathematical model of a dynamical system equipped with a clock that measures time. Timed automata were used in the same sense that differential equations underlie a large number of physics and traditional engineering problems. However, the basic timed automata formalism was extended to allow the continuous consumption of resources, such as energy, to be modelled and analysed. In this way, different feasible schedules could be distinguished according to their consumption of resources, with obvious preference for the optimal schedule with the minimal resource requirements. The algorithms developed for priced timed automata have already been made available in the recently released real-time verification tool UPPAAL CORA. With the help of this technology, dedicated to analysing and automatically debugging complex reactive systems, several challenging industrial problems were tackled. These include scheduling lacquer production and a car periphery supervision system, as well as the implementation of a biphase mark protocol.
