AsmetaA: Animator for Abstract State Machines

Lecture Notes in Computer Science, 2016

Formal models are a rigorous way to specify informal system requirements. However, they are not widely used in practice, since they are considered difficult to develop and understand. Visualization is often considered a good means for people to communicate and to get a common understanding. We here make a proposal of a visual notation for Abstract State Machines (ASMs), and we introduce visual trees that visualize ASM transition rules. In addition to these graphical components that are based only on the syntactical structure of the model, we also present visual patterns that permit to visualize part of the behavior of the machine. A tool is also available to graphically represent ASM models using the proposed notation.

A formal specification is a mathematical description of a given system. Writing a formal specification for real-life, industrial problems is a difficult and error prone task, even for experts in formal methods. It is crucial to get the approval and feedback when domain experts have a lack of knowledge of any specification language, to avoid the cost of changing a specification at later stage of development. This paper introduces a new functional architecture, together with a direct and efficient method of using real-time data set, in a formal model without generating the legacy source code in any target language. The implemented architecture consists of six main units. These units are: Data acquisition and preprocessing unit; Feature extraction unit; Database; Graphical animations dedicated tool: Macromedia Flash; Formal model animation tool Brama plug-in to interface between Flash animation and Event-B model; and formal specification system Event-B. These units are invoked independently and allow for simple algorithms to be executed concurrently. All the units of this proposed architecture help to animate the formal model with real-time data set and offer an easy way for specifiers to build a domain specific visualization that can be used by domain experts to check whether a formal specification corresponds to their expectations.

This paper explores the possibility to incorporate validation of formal specifications into their step-wise development process. The key idea in formal methods to assess that an implementation is correct is to break the verification into smaller proofs associated with each refinement step. Likewise, the technique of animation could be used with each refinement step to break its validation into smaller assessments. Animating an abstract specification often requires to alter it in ways that proof obligations cannot be discharged anymore. So, we have developed a process and a set of transformation rules whose application produce an animatable specification which may be non-provable, but which is guaranteed to have the same behavior. 10 rules have been identified; they are presented and discussed with a special emphasis on their validity. We relate how step-wise animation is used in two case studies and what we gain from this. * This work has been partially supported by the ANR (National Research Agency) in the context of the TACOS project, whose reference number is ANR-06-SETI-017 (http://tacos.loria.fr), and by the Pôle de Compétitivité Alsace/Franche-Comté in the context of the CRISTAL project (http://www.projet-cristal.org).

… Conference on Informatics …

The X-machine formal method forms the basis for a specification/modeling language with a substantial potential value to software engineers. An X-machine is a more expressive and flexible state machine, capable of modeling both the dynamic and the static aspect of a system. Communicating X-machines provide a methodology for building communicating systems out of existing stand-alone X-machines. However, for practically using the model in an real-world system development process, a tool for demonstrating and informally verifying the properties of the modeled system is required. An ideal platform for efficiently implementing such a tool, should support, process oriented programming, efficient communication primitives and declarativeness. Cspcons is a distributed CLP platform that supports program execution over multiple independent sequential CLP processes that synchronize though message and event passing. The present paper demonstrates the applicability of the Cspcons programming model to the implementation of a communicating X-machine animator tool that will act as the basis for an extended set of tools that will support the formal mathematical analysis of the specified X-machine models.

: This codeless method of programming using ASMs is not only capable of producing transparent software but reliable, proven and checked, all the way through its specification as ground model to its implementation. In other words evolving algebra method supports all the software life-cycle phases from initial specifications or requirement gathering to executable code. Above all, this method is platform independent and the ease with which computer scientist can build simple and clean system models out of evolving algebra pushes further the potential it needs to influence future industrial formal methods techniques. This formal specifications and designs demonstrate the consistency between the specifications and the code for all possible data inputs at various levels of abstractions.