Title: Modular discrete time approximations of distributed hybrid automata

Speaker: Shaofa Yang (Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences)

Time: 10:00, Wednesday, September 26th, 2012

Venue: Lecture Room, 3rd Floor, Building 5#, State Key Laboratory of Computer Science, Institute of Software, Chinese Academy of Sciences

Abstract:

We consider a network of controllers that observe and control a plant whose Dynamics is determined by a finite set of continuous variables. At any given time a variable evolves at a constant rate. However, a controller can switch the rates of a designated subset of the continuous variables. These mode changes are determined by the current values of a designated subset of the variables that the controller can observe. Each variable's rate is controlled by exactly one controller and its value is observed by at most one controller. We model this setting as a network of hybrid automata and study its discrete time behavior.

We show that the set of global control state sequences displayed by the network is regular. More importantly, we show that one can succinctly represent this regular language as a family of communicating finite state automata. We allow the observation of the variables and the changes in the rates of the variables to incur delays. We also permit the digital clocks associated with the controllers to evolve at different---but rationally related---rates.

This is joint work with P. S. Thiagarajan.

Bio:

Shaofa Yang is presently a faculty member at Shenzhen Institute of Advanced Technology (SIAT), Chinese Academy of Sciences. His current research interests are in verification of hybrid (discrete-continuous) systems. He also did work in the areas of logics in computer science, concurrency theory (Petri nets, message sequence charts) and control synthesis. In 1996, he was selected jointly by the Ministry of Education of China, and that of Singapore, to receive a generous scholarship for undergraduate studies in Singapore, attached with a bond of six-year employment in Singapore upon graduation. He obtained his Bachelor's degree, master's degree and PhD degree, respectively, in 2000, 2003, 2006, from the computer science department of National University of Singapore. And he cleared the six-year bond by working as a teaching assistant in the same department from 2000 to 2006. Before joining SIAT, he held post-doctoral positions at INRIA, France, and UNU-IIST, Macau.