Julien Deantoni

Execution of heterogeneous models for thermal analysis with a multi-view approach

To deal with the high complexity of embedded systems, engineers rely on high-level heterogeneous models that combine functional and non-functional aspects, hardware/software artifacts, structural and behavioral descriptions. PRISMSYS is a system-level multi-view modeling framework, which provides a means to specify functional and non-functional aspects in interrelated views. Each concern/view is addressed separately with a dedicated set of models and correspondence rules, maintaining the semantic consistency between those different views. The behavioral specification mixes UML state machines with equational models defined as SYSML parametric diagrams. To supply a complete non-functional property-aware simulation environment, it is mandatory to formalize 1) the execution semantics of the UML state machines, 2) the SYSML parametric diagrams and 3) the coordination between them. This is achieved by using CCSL, the Clock Constraint Specification Language, to provide an event-based semantics for each model and their coordination. The proposed co-simulation framework combines TIMESQUARE, a discrete event simulator for CCSL, and Scilab, a tool for numerical computation. The framework is illustrated on a CPU thermal manager case study with a joint simulation of both its functional and non-functional models.

Generating EAST-ADL Event Chains from Scenario-Based Requirements Specifications

Real-time software-intensive embedded systems complexity, as in the automotive domain, requires rigorous Requirements Engineering (RE) approaches. Scenario-based RE formalisms like Modal Sequence Diagrams (MSDs) enable an intuitive specification and the simulative validation of functional requirements. However, the dependencies between events occurring in different MSD scenarios are implicit so that it is difficult to find causes of requirements defects, if any. The automotive architecture description language east-adl addresses this problem by relying on event chains, which make dependencies between events explicit. However, east-adl event chains have a low abstraction level, and their relationship to functional requirements has seldom been investigated. Based on the east-adl functional architecture, we propose to use its central notion of event to conciliate both approaches. We conceived an automatic transformation from the high abstraction level requirements specified in MSDs to the low abstraction level event chains.