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EECE 396-1 Hybrid and Embedded Systems: Computation. T. John Koo, Ph.D. Institute for Software Integrated Systems Department of Electrical Engineering and Computer Science Vanderbilt University 300 Featheringill Hall January 29, 2004 john.koo@vanderbilt.edu
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EECE 396-1Hybrid and Embedded Systems: Computation T. John Koo, Ph.D. Institute for Software Integrated Systems Department of Electrical Engineering and Computer Science Vanderbilt University 300 Featheringill Hall January 29, 2004 john.koo@vanderbilt.edu http://www.vuse.vanderbilt.edu/~kootj
Hybrid System • A system built from atomic discrete components and continuous components by parallel and serial composition, arbitrarily nested. • The behaviors and interactions of components are governed by models of computation (MOCs). • Discrete Components • Finite State Machine (FSM) • Discrete Event (DE) • Synchronous Data Flow (SDF) • Continuous Components • Ordinary Differential Equation (ODE) • Partial Differential Equation (PDE)
Topics • Finite Automata • Transition Relation = Edges + Guard • Ordering of events • Timed Automata • Notions of time: Global/Local Clocks • Transition Relation • Total ordering of events • Multi-rate time automata • Example • Rate Monotonic Scheduling • Train Gate model • Ref: • [1] R. Alur, T.A. Henzinger, and P.-H. Ho. Automatic Symbolic Verification of Embedded Systems. IEEE Transactions on Software Engineering 22:181-201, 1996. • [2] T.A. Henzinger, P.-H. Ho, and H. Wong-Toi. HyTech: A Model Checker for Hybrid Systems. Software Tools for Technology Transfer 1:110-122, 1997.
Timed Automata GPS INS
Train Gate model • The gate controller of a railroad crossing has a delay of a seconds; that is, the gate starts closing a seconds after a train signals its approach. HyTech computes the safe values of a such that the gate is fully closed whenever the train is within 10 meters of the gate. • Reference and On-Line Demo: • www-cad.eecs.berkeley.edu/~tah/HyTech/demo.html