Abstract: Problem statement: Event-based systems have importance in many application domains ranging from real time monitoring systems in production, logistics, medical devices and networking to complex event processing in finance and security. The increasing popularity of Event-based systems has opened new challenging issues for them. One such issue is to carry out requirements analysis of event-based systems and build conceptual models. Currently, Object Oriented Analysis (OOA) using Unified Modeling Language (UML) is the most popular requirement analysis approach for which several OOA tools and techniques have been proposed. But none of the techniques and tools to the best of our knowledge, have focused on event-based requirements analys...