Reactive Systems

Reactive Systems

Topic:

Specification of reactive systems, including consideration of states

Coordinator:

Egidio Astesiano (Genova) and Heinrich Hussmann (Munich)

Mailing List:

cofi-reactive

Notes Series:

see the CoFI Reactive Systems Home Page below

Home Page:

http://www.disi.unige.it/person/ReggioG/COFI/index.html, mirror

An area of particular interest for applications is that of reactive, concurrent, distributed and real-time systems. There is considerable past work in algebraic specification that tackles systems of this kind, but nonetheless the application of Casl to such systems is speculative and preliminary in comparison with the rest of CoFI. The aim here is to propose and develop one or more extensions of Casl to deal with systems of this kind, and to study methods for developing software from such specifications. Extensions in three main categories are currently being considered:

• Combination of formalisms for concurrency (e.g. CCS, Petri nets, CSP) with Casl for handling classical (static) data structures;
• Formalisms built over Casl, where processes are treated as special dynamic data; and
• Approaches where Casl is used for coding, at the meta-level, some formalism for concurrency, as an aid to reasoning.

Since object-oriented methods have a dominant role in concrete developments, the group will address OO aspects insofar they are needed for reaching the above goals, but object orientation is not addressed as an independent topic in itself.

Work in this area begun only after the design of Casl was complete and so it is still in its early stages. Presently, the work is organized in two tracks: autonomous and coordinated extensions.

Autonomous Extensions:

Coordinated Effort:

• The basic idea is to adopt Casl, or an extension of it, for annotating UML, thus possibly replacing OCL (work led by Heinrich Hussmann, Dresden).
• We have joined the activity of the free group Precise UML; the goal is to provide a formal/rigorous underpinning of UML, possibly exploiting CoFI-related techniques. A sketchy proposal for a general approach to the problem has been presented at a workshop at OOPSLA'98 [2]. Two other draft papers are available, one relating the ADT approach to UML [23] and the other proposing an underlying model for UML state machines [46].

Reactive Systems