Accessing Databases within Esterel

A current limitation of the Esterel language for reactive-systems design is its lack of support for accessing databases. This talk presents the results of a summer student project which investigated a way of integrating databases and Esterel by providing an API for database use inside Esterel. A case study, involving a warehouse storage system built using Lego Mindstorms robotics kits, demonstrates the utility of the API. This system employs an Esterel-programmed robot whose task it is to collect various items from a customer\u27s order and assemble them in one place. To do so, the robot accesses customer-order data and floor-plan data stored in a database

Summary Refinement Patterns for Contractual Statecharts

The strategic goal of this project is to improve the theoretical bases and corresponding tool support for the design languages and methodologies that are widely used for building avionics and aerospace systems. Existing languages, particularly the popular Stateflow statecharts, lack in expressiveness and tool support for refinement-based designs as practised by engineers. In particular, they have no support for declarative styles of specification used at early design stages, and their semantics do not entirely benefit from the existing wealth of research on concurrent systems and semantics in component–based design. The specific novel contributions of this proposed research project are: 1. The definition of the syntax and semantics of an extension of Stateflow statecharts, Contractual Statecharts, which supports developers in writing models in mixed declarative and operational specification styles; 2. A refinement relation for component–based, stepwise design that allows for trading off operational for declarative content in models; 3. Supporting simulation and model checking tools, which shall be developed and implemented so as to integrate with the industry-standard Stateflow tool, to enable engineers to analyse their mixed–style models; 4. A set of refinement patterns capturing standard rules expressing how to translate between declarative and operational styles of specification, and a tool assisting in the application of refinement patterns. The project will be driven by industrial case studies and, where necessary, will involve feedback from the industrial partner on the utility of the language, supporting tools and patterns

A Logical Process Calculus

This paper presents the Logical Process Calculus (LPC), a formalism that supports heterogeneous system specifications containing both operational and declarative subspecifications. Syntactically, LPC extends Milner's Calculus of Communicating Systems with operators from the alternation-free linear-time mu-calculus (LT(mu)). Semantically, LPC is equipped with a behavioral preorder that generalizes Hennessy's and DeNicola's must-testing preorder as well as LT(mu's) satisfaction relation, while being compositional for all LPC operators. From a technical point of view, the new calculus is distinguished by the inclusion of: (1) both minimal and maximal fixed-point operators and (2) an unimple-mentability predicate on process terms, which tags inconsistent specifications. The utility of LPC is demonstrated by means of an example highlighting the benefits of heterogeneous system specification

Saturation: An efficient iteration strategy for symbolic state-space generation

This paper presents a novel algorithm for generating state spaces of asynchronous systems using Multi-valued Decision Diagrams. In contrast to related work, the next-state function of a system is not encoded as a single Boolean function, but as cross-products of integer functions. This permits the application of various iteration strategies to build a system's state space. In particular, this paper introduces a new elegant strategy, called saturation, and implements it in the tool SMART. On top of usually performing several orders of magnitude faster than existing BDD-based state-space generators, the algorithm's required peak memory is often close to the nal memory needed for storing the overall state spaces