Verifying scenarios with time Petri-nets

Recently, a substantial amount of research activities has been focused on a user-oriented perspective to the development of software systems. One of the key elements in this perspective is the notion of scenarios: a description of what people do and experience as they try to make usage of computer systems and applications. A variety of applications of scenarios has been proposed, for example, to elicit user requirements, or to validate requirements specifications. As scenarios are useful for the lifecycle of requirements engineering, it is important to enable verification of these scenarios, especially, to detect any wrong information and missing information that are hidden in scenarios. However, scenarios are usually stated in an informal way, which impedes the easiness for verification. The focus of this paper is on the use of time Petri-nets (TPNs) to serve as the verification mechanism for the acquired scenarios. Use cases are used to elicit the user needs and to derive the scenarios. Each of the use cases is described from a user's perspective and depicts a specific flow of events in the system. After specifying all possible scenarios, each of them can be transformed into its correspondent time Petri-nets model. Through the analysis of these TPNs models, wrong information and missing information in scenarios can be detected. The proposed approach is illustrated by means of a course registration problem domain. (C) 2001 Elsevier Science B.V. All rights reserved.