Multi-modal scenarios revisited: A net-based representation

Live sequence charts (LSC) is a visual formalism that can be used to model reactive systems. In terms of LSC, a system model is a set of charts, each of which may be referred to as a multi-modal scenario. In this paper, we revisit the scenarios of the UML2-compliant dialect of LSC. We abstract from their concrete visual representation, and show how to capture multi-modal scenarios in a flexible, yet conservative, way. For this, we use the building blocks of Petri nets; i.e., places and transitions, extendedwithmodalities and interpreted in accordance with the semantics of LSC. This results in what we refer to as LSC nets. LSC nets can express a variety of advanced constructs of LSC, as well as several semantic variations suggested in the literature, with just a few primitive notions. At the same time, the net corresponding to an LSC involves rather superficial, technical, changes in presentation. As a result, LSC nets form a rigorous basis to present, discuss, and investigate the language as a whole, or interesting fragments thereof. © 2011 Elsevier B.V. All rights reserved.