SHIFT: A Formalism and a Programming Language for Dynamic Networks of Hybrid Automata

Aleks Gollu Assistant Research Engineer
PATH/ITS

Thursday, January 30, 1997
Hogan Room, 531 Cory Hall
5:00-6:00 p.m.

Abstract:

SHIFT is a programming language for describing dynamic networks of hybrid automata. Such systems consist of components which can be created, interconnected and destroyed as the system evolves. Components exhibit hybrid behavior, consisting of continuous-time phases separated by discrete-event transitions. Components may evolve independently, or they may interact through their inputs, outputs and exported events. The interaction network itself may evolve.

We believe that the SHIFT model offers the proper level of abstraction for describing complex applications such as automated highway systems, air traffic control systems, robotic shopfloors, coordinated submarines and other systems whose operation cannot be captured easily by conventional models.

We have implemented a compiler for translating a SHIFT program to a C program, and we have implemented the SHIFT run-time system for obtaining an executable program. The executable program, when run, simulates the design specified in the SHIFT source program.

We have used SHIFT to create SmartAHS, a full functionality micro-simulator for all aspects of the Automated Highway System (AHS). It simulates vehicle dynamical behaviors under various control laws, roadway configurations and geometries. Local, link, and network impacts can all be investigated using SmartAHS.

This presentation will discuss the SHIFT language and the underlying mathematical model. We will use examples to illustrate the use of SHIFT and its key characterisitcs.

Postscript of slides