1. DEPARTMENT OF COMPUTER SCIENCE TARI ROROHIKO Control and Automation Robi Malik Department of Computer Science The University of Waikato robi@cs.waikato.ac.nz Analysis and Synthesis of Finite-State Systems

2. 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

3. 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

4. 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

5. 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

6. 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

7. 15 June 2005 © THE UNIVERSITY OF WAIKATO TE WHARE WANANGA O WAIKATO 7 Example of Using Synthesis 4 3 2 1 1 2 3 ?

8. 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.