Towards Automatic Generation of Formal Scenarios Specifications from Real-Time Reactive Systems Requirements Written in NL Las Vegas Nevada, USA, June 26-29, 2006 O. Ormandjieva, I. Hussain Department of Computer Science and Software Engineering Concordia University Montreal, Quebec, Canada Abstract - This paper describes a new method for automatic generation of formal scenario-based specifications from requirements written in structured natural language (NL). The goal is to allow for completion of the formalization of the real-time reactive systems development process from users’ requirements. We believe this method would guarantee the correctness and the completeness of the scenarios generated in the requirements specification phase, thus decreasing the probability of errors in the subsequent development phases. To our knowledge, the approach is completely new in the field of requirements engineering. Keywords: Real-Time Reactive System, Generation of System-Level Formal Scenarios, Requirements Engineering, Natural Language Processing. 1.0 Introduction The correctness and completeness of the scenarios specifications generated in the analysis phase is crucial for the development of quality software, as errors introduced at this stage and propagated to implementation are extremely costly to fix. This is particularly true for real-time reactive systems [2] which are largely event-driven, interacting intensively and continuously with the environment through stimulus-response behavior and are regulated by strict timing constraints. Examples of such systems include emergency alarm systems, air traffic control systems, nuclear reactor control systems and telecommunication systems. The goal of this paper is to introduce a new approach for automatic generation of formal scenario-based specifications from textual requirements of real-time reactive systems written in structured English. In the context of real-time reactive systems, which are mostly safety- critical, the main motivation for formalization of the development process comes from the requirements for correct implementation of time- dependent behavior. Our aim is to assist developers in the tedious task of developing correct and complete scenarios for such complex systems. To guarantee the correctness, we propose to automatically generate all possible traces of interactions between the users and the system (giving rise to scenarios), which exhaustively cover the possible behaviors of the system. The completeness is achieved through automatically selecting only a subset of scenarios, which represent the critical system’s behavior, based on certain criteria.