LSCs: That’s the Name of the Game! A Specification Framework based on Live Sequence Charts and Game Theory

Message Sequence Charts (MSCs) are a standard, widely adopted scenario-based notation. However, its use for the requirements engineering of reactive systems still suffers fundamental issues about which few researchers and practitioners seem to care: (1) its semantics is too weak to model such basic things as a response pattern, (2) no distinction is made between descriptive and prescriptive statements, (3) it is impossible to deal with class-level scenarios. We take up the seminal work of Harel and Damm on Live Sequence Charts (an extension of MSCs) and elevate the notation to the status of full-fledged requirements engineering language for specifying functional properties of reactive systems. We do this by (1) extending LSCs syntax, (2) providing a semantics based on game theory, (3) defining proof obligations, (4) giving direction for implementing automated verification mechanisms and (5) illustrating our contributions on an air traffic control case-study.