Message sequence chart : syntax and semantics
Michel A. Reniers · Centrum Wiskunde & Informatica (CWI), the national research institute for mathematics and computer science in the Netherlands · 1999
The subject of this thesis is the language Message Sequence Chart (MSC) and the definition of its formal semantics.Message Sequence Chart is a graphical language for the description of the interactions between system components.Every system component is represented by a vertical line called an instance.Along an instance, 1The extension of the language MSC with features for describing the composition of MSCs has been influenced greatly by the operators in the language Interworking.A difference between the composition operators in MSC and in Interworking is that the language MSC offers a graphical means of describing these compositions instead of a textual one.• a clear commitment of the Formal Methods Group of Eindhoven University of Technology and of Philips Research Laboratories Eindhoven to actively participate in the standardization committee was given.As mentioned before this has led to the standardization of a formal semantics of MSC92.This thesis reports on the research that has been performed in order to define a semantics for the language MSC96.Related to the use of MSC for the description of requirements is the use of MSC in connection with use cases [JCJ092].In the Unifying Modeling Language (UM-L) [BJR96] and related object oriented methods, use cases are a key ingredient in the development process.Use cases describe the typical interactions between the user and a system.Most of the time, use cases are simply described in natural language.In UML, sequence diagrams are used for visualizing a single use case.These sequence diagrams are very close to MSC.Currently, there is a debate on using MSCs for the formalization of use cases [AB95]. Visualization and simulation Because of their emphasis on communication and not on internal process behavior MS Cs are. very useful for presenting an overview of the Structure of this thesisThis thesis is structured as follows.In Chapter 2, the language MSC as it is standardised by the ITU in October 1996 is introduced.The language elements are introduced piecewise and for each language element the graphical syntax is explained and illustrated, an informal explanation of the semantics is provided, and the textual syntax is explained and illustrated.This chapter presents the language MSC in an informal but nevertheless rigorous way.After finishing this chapter the reader should have a