Sébastien Gérard

Challenges in Combining SysML and MARTE for Model-Based Design of Embedded Systems

Using model-based approaches for designing embedded systems helps abstract away unnecessary details in a manner that increases the potential for easy validation and verification, and facilitates reuse and evolution. A common practice is to use UML as the base language, possibly specialized by the so-called profiles. Despite the ever increasing number of profiles being built in many domains, there is still insufficient focus on discussing the issue of combining multiple profiles. Indeed, a single profile may not be adequate to cover all aspects required in the multidisciplinary domain of embedded systems. In this paper, we assess possible strategies for combining the SysML and MARTE profiles in a common modelling framework, while avoiding specification conflicts. We show that, despite some semantic and syntactical overlapping, the two are highly complementary for specifying embedded systems at different abstraction levels. We conclude, however, that a convergence agenda is highly desirable to align some key language features.

Annotating UML models with non-functional properties for quantitative analysis

This work is motivated by the recent Request For Proposals issued by OMG for a new UML Profile named “Modeling and Analysis of Real-Time and Embedded systems”. The paper describes first some domain concepts for annotating Non-Functional Properties (NFPs), whose focus is on supporting temporal verification of UML-based models. Particular emphasis is given to schedulability and performance analysis for real-time systems. We discuss next some general requirements for NFP annotations and evaluate how the UML profiles for “Schedulability, Performance, and Time Specification” and for “Modeling Quality of Service and Fault Tolerance Characteristics and Mechanisms”, address these requirements. Last but not least, the paper proposes a preliminary framework for describing NFPs by considering the major requirements previously stated and by analyzing some UML mechanisms to attach NFPs to model elements.

Modeling and analysis of real-time and embedded systems

This paper presents an overview of the workshop MARTES on Modeling and Analysis of Real-time and Embedded Systems that has taken place for the first time in association with the MODELS/UML 2005 conference. The main themes discussed at this workshop concerned (1) methodologies and tools for quantitative analysis and (2) methodologies and languages for modeling quantitative aspects of real-time and embedded systems in the context of model driven development.

First Experiments Using the UML Profile for MARTE

A UML profile for Modeling and Analysis of Real-Time and Embedded systems (MARTE) has been recently standardized by the OMG. This initiative meets the needs of several Thales divisions (e.g., aerospace, land and joint and air systems), which develop real-time and embedded systems. CEA LIST, INRIA and Thales have been the main contributors to the MARTE standard through the ProMARTE consortium. To foster the deployment of MARTE in Thales divisions, we have launched the development of a case study related to a real-time and embedded system using the MARTE adopted specification. As a first step of this study, we make use of a fictive system- the Josefil challenge-to evaluate whether the profile is applicable to the Thales current systems and software engineering practices. The purpose of this paper is to report on this first stage and outline the next scheduled activities.

Consolidated Product Line Variability Modeling

In this chapter we present an improved and simplified metamodel for product line variability. This model has been consolidated from diverse approaches in the earlier research projects ESAPS, CAF and other existing work, supplied with recent research in FAMILIES. The consolidated metamodel aims to be the starting point for standardization. A standard will lay the grounds for commercial and open-source tool support. We present here a prototype tool based on the metamodel. To put the work in context, we present three different approaches for capturing variability: using standard languages (exemplified by UML 2.0), using annotations to standard languages, and using domain-specific languages. We use the same Watch example to present how variability is handled in all three approaches.

Model-Driven analysis and synthesis of concrete syntax

Metamodeling is raising more and more interest in the field of language engineering. While this approach is now well understood for defining abstract syntaxes, formally defining concrete syntaxes with metamodels is still a challenge. Concrete syntaxes are traditionally expressed with rules, conforming to EBNF-like grammars, which can be processed by compiler compilers to generate parsers. Unfortunately, these generated parsers produce concrete syntax trees, leaving a gap with the abstract syntax defined by metamodels, and further ad-hoc hand-coding is required. In this paper we propose a new kind of specification for concrete syntaxes, which takes advantage of metamodels to generate fully operational tools (such as parsers or text generators). The principle is to map abstract syntaxes to concrete syntaxes via bidirectional mapping-models with support for both model-to-text, and text-to-model transformations.

Optimum: a MARTE-based methodology for schedulability analysis at early design stages

The construction of a design model is a critical phase in RTS development as the choices made have a direct impact on timing aspects. In traditional model-based approaches, the design relies largely on the designer experience. Once the design model is constructed, a convenient schedulability test has to be found in order to ensure that the design allows the respect of the timing constraints. This late analysis does not guarantee the existence of a test for the given design and does not allow early detection of unfeasible designs. In order to enhance reliability of RTS, this paper proposes a two step methodology for schedulability-aware real-time software design models construction. Having a high-level functional model as entry, the first methodology step consists in the workload model specification. The workload model represents the system end-to-end workload of critical scenarios triggered by an external stimulus and subject to hard-real time constraints. The second step is the refinement of the workload model towards a Schedulability Analysis Model defining an appropriate and analyzable threading strategy model. The threading strategy defines the set of units of execution taken into account by the scheduler of the system and their scheduling parameters. Different threading strategies can be then evaluated from a schedulability point of view in order to guide the designer towards the choice of the most appropriate one

Managing Complexity of Automotive Electronics Using the EAST-ADL

The complexity of embedded automotive systems calls for a more rigorous approach to system development compared to current state of practice. A critical issue is the management of the engineering information that defines the embedded system. Development time, cost efficiency, quality and dependability all benefit from appropriate information management. System modeling based on an architecture description language is a way to keep the engineering information within one information structure. The EAST-ADL was developed in the EAST-EEA project (www.easteea.net) and is an architecture description language for automotive embedded systems. It is currently refined in the ATESSTproject (www.atesst.org). This paper gives an overview of the EAST-ADL and accounts for some recent refinements as developed in the ATESST project. Areas covered include the relation to other standardization initiatives such as UML2.0, AADL, AUTOSAR, SysML, Marte profile, requirements management and variability.

Validation and automatic test generation on UML models: the AGATHA approach

UML-based methodologies take more and more space in the software development domain. In addition, the need to validate applications as early as possible in the development cycle is now mandatory to satisfy cost and time-to-market constraints. In this context, this paper describes, first, how to bridge the gap between semiformal UML models and a formal technology ensuring test case generation. Second, the formal tool used to automatically generate test sequences, named AGATHA, is described in minute detail. Finally, this approach is illustrated throughout by a toy example of an elevator system.

Enabling Scheduling Analysis for AUTOSAR Systems

AUTOSAR (Automotive Open System Architecture) is enjoying increasing interest and broad acceptance in the automotive domain. AUTOSAR aims at defining an open standardized software architecture to face future challenges in automotive development including the development of time-critical systems (e.g. brake-by-wire or steer-by-wire). Mastering the development of such systems requires being able to analyze their real-time behavior. Scheduling analysis is the theory that studies how far a real-time system may satisfy its real-time requirements against its real-time properties. In this paper, we will study to what extent it is possible to apply some of those scheduling analysis techniques on real-time systems deployed on AUTOSAR-compliant architectures. The paper focuses on scheduling analysis techniques implemented in one open source tool. A concrete case study shows the feasibility of the approach and shows scheduling analysis results.