Summary: Event­Clock Automata:
A Determinizable Class of Timed Automata \Lambda
Rajeev Alur y Limor Fix z Thomas A. Henzinger x
Abstract. We introduce event­recording automata. An event­recording automaton
is a timed automaton that contains, for every event a, a clock that records the time
of the last occurrence of a. The class of event­recording automata is, on one hand,
expressive enough to model (finite) timed transition systems and, on the other hand,
determinizable and closed under all boolean operations. As a result, the language­
inclusion problem is decidable for event­recording automata. We present a translation
from timed transition systems to event­recording automata, which leads to an algorithm
for checking if two timed transition systems have the same set of timed behaviors.
We also consider event­predicting automata, which contain clocks that predict the
time of the next occurrence of an event. The class of event­clock automata, which contain
both event­recording and event­predicting clocks, is a suitable specification language for
real­time properties. We provide an algorithm for checking if a timed automaton meets
a specification that is given as an event­clock automaton.
1 Introduction
Finite automata are instrumental for the modeling and analysis of many phenomena within com­
puter science. In particular, automata theory plays an important role in the verification of con­
current finite­state systems [15, 21]. In the trace model for concurrent computation, a system is

Source: Alur, Rajeev - Department of Computer and Information Science, University of Pennsylvania

Collections: Computer Technologies and Information Sciences