On Checking Timed Automata for Linear Duration Invariants on Checking Timed Automata for Linear Duration Invariants

The mission of UNU/IIST is to assist developing countries in the application and development of software technology. UNU/IIST contributes through its programmatic activities: 1. advanced development projects in which software techniques supported by tools are applied, 2. research projects in which new techniques for software development are investigated, 3. curriculum development projects in which courses of software technology for universities in developing countries are developed, 4. courses which typically teach advanced software development techniques, 5. events in which conferences and workshops are organised or supported by UNU/IIST, and 6. dissemination, in which UNU/IIST regularly distributes to developing countries information on international progress of software technology. Fellows, who are young scientists and engineers from developing countries, are invited to actively participate in all these projects. By doing the projects they are trained. At present, the technical focus of UNU/IIST is on formal methods for software development. UNU/IIST is an internationally recognised center in the area of formal methods. However, no software technique is universally applicable. We are prepared to choose complementary techniques for our projects, if necessary. UNU/IIST produces a report series. Reports are either Research R , Technical T , Compendia C or Administrative A. They are records of UNU/IIST activities and research and development achievements. Many of the reports are also published in conference proceedings and journals. Abstract In this work, we address the problem of verifying a Timed Automaton for Duration Calculus formula in the form of Linear Duration Invariants. Accurate methods 14] seem not practical even for small examples. We present a conservative method for solving the problem that is based on linear programming techniques applied on an algebraic representation of Timed Automata. We also provide a translation procedure from Timed Automata to this sort of regular expressions for real-time languages. Some previous linear programming-based approaches 8] work for algebraic notations which are less expressive than Timed Automata. In comparison to these approaches, our method is more general: Timed Automata are our starting point and we provide an accurate answer to the problem for a larger (and representative) class of them. Victor Braberman is a PhD Candidate at the University of Buenos Aires, Argentina. He was a UNU/IIST fellow from September, 1997 to February 1998. His main research interests are the formal modelling, veriication and testing of Real-Time Systems.