DEPARTMENT OF COMPUTER SCIENCE TARI ROROHIKO Control and Automation Robi Malik Department of Computer Science The University of Waikato Analysis and Synthesis of Finite-State Systems

15 June 2005 © THE UNIVERSITY OF WAIKATO TE WHARE WANANGA O WAIKATO 2 Control Systems Technical devices  Household equipment  Automotive electronics  Industrial plants All these are …  often safety-critical  reactive systems

15 June 2005 © THE UNIVERSITY OF WAIKATO TE WHARE WANANGA O WAIKATO 3 Model Checkers Real-world system Never blow up! Desired property AG  blow_up Logic formula Finite-state model Model checker Yes or  No

15 June 2005 © THE UNIVERSITY OF WAIKATO TE WHARE WANANGA O WAIKATO 4 Central Locking System Model:  Finite-state machines  Composed by strict synchronisation timer wsptime

15 June 2005 © THE UNIVERSITY OF WAIKATO TE WHARE WANANGA O WAIKATO 5 Model Checking Large Systems Central Locking System  51 automata  7.5  10 8 reachable states Conflicting ! timer wsptime

15 June 2005 © THE UNIVERSITY OF WAIKATO TE WHARE WANANGA O WAIKATO 6 Verification vs. Synthesis Verification  Check whether a given system satisfies desired properties  Find bugs Synthesis  Automatically construct a system from its desired properties Real-world system Never blow up! Desired property

15 June 2005 © THE UNIVERSITY OF WAIKATO TE WHARE WANANGA O WAIKATO 7 Example of Using Synthesis ?

15 June 2005 © THE UNIVERSITY OF WAIKATO TE WHARE WANANGA O WAIKATO 8 Control Systems at Waikato Using and developing tools to …  edit finite-state models,  check properties,  synthesise controllers,  using new methods to do this in a smart way.