Abstract State Processes

Abstract

Abstract. Process-algebraic languages offer a rich set of structuring techniques and concurrency patterns which allow one to decompose complex systems into concurrently interacting simpler component processes. They abstract however almost entirely from a notion of system state. The method of Abstract State Machines (ASMs) offers powerful abstraction and refinement techniques for specifying system dynamics based upon a most general notion of structured state. The evolutions of the state are governed however by a fixed and typically unstructured program, called 'rule', which describes a set of abstract updates occurring simultaneously at each step (synchronous parallelism). We propose to incorporate into one machine concept the advantages offered by both structuring techniques, and introduce to this purpose Abstract State Processes (ASPs), i.e. evolving processes (extended ASM programs which are structured and evolve like process-algebraic behaviour expressions) operating on evolving abstract states the way traditional ASM rules do.

The Abstract State Machines Method for High-Level System Design and Analysis

“…It is also often used to define what among the class of all possible runs of an ASM is considered as a legal run, describing axiomatically a certain number of features one wants to abstract away at the investigated level of abstraction. Similarly, whatever one wants to classify as an event can be included into the declaration of the state signature and be treated correspondingly in rule guards; see for example Event-B, where events are considered as rule firings, or [14] where process-algebraic event-based structuring techniques and concurrency patterns are combined with the state-based abstraction mechanism and synchronous parallelism of ASMs.…”

“…of an FSM, which however is particularly useful for modeling control systems, protocols, business processes and the like. 14 We therefore proposed in [22] To display such rules often the standard graphical notation for FSMs is used, where circles represent the control states, rhombs the guard cond ition and rectangles the rule body. See Fig.…”

Abstract State Machines: a unifying view of models of computation and of system design frameworks

“…Successful projects in this direction have been reported using theorem proving systems (KIV, PVS, Isabelle) and model checkers, see the survey paper [14] for details. See also [10] for an integration of process-algebraic and ASM concepts.…”

Stepwise Refinement of Processes

“…It has been noted [25] that to model components in a modular style it would be useful to combine the event-based reasoning of process algebra with state-based reasoning. But it has been commented [24] that in order for process algebras to become of greater use in practice there is a need for a more well-defined methodology.…”