Modèle de contraintes temporelles pour systèmes polychrones

International audienceLa modélisation des systèmes répartis et des systèmes électroniques modernes nécessite des référentiels temporels multiples. Nous désignons ces systèmes sous le nom de “systèmes polychrones”. Le profil UML pour les systèmes temps réel et embarqués (MARTE) permet leur modélisation ainsi que la spécification de contraintes temporelles avec CCSL (Clock Constraint Specification Language). Dans MARTE, CCSL est non normatif et sa sémantique est informelle. Nous proposons ici une sémantique formelle en termes d'évolutions d'un “Time System” pour un noyau de CCSL. Un “Time System” est un modèle dynamique qui associe un ensemble de configurations à un modèle structurel constitué d'un ensemble d'horloges discrètes et de relations sur ces horloges. Les Time Systems sont comparés à d'autres modèles de causalités asynchrones, synchrones et polychrones. CCSL et sa mise en oeuvre sont illustrés sur un exemple de contrôleur d'ABS

Correctness Issues on MARTE/CCSL constraints

International audienceThe UML Profile for Modeling and Analysis of Real-Time and Embedded systems promises a general modeling framework to design and analyze systems. Lots of works have been published on the modeling capabilities offered by MARTE, much less on available verification techniques. The Clock Constraint Specification Language (CCSL), first introduced as a companion language for MARTE, was devised to offer a formal support to conduct causal and temporal analysis on MARTE models.This work relies on a state-based semantics for CCSL to establish correctness properties on MARTE/CCSL specifications. We propose and compare two different techniques to build the state-space of a specification. One is an extension of some previous work and is based on extended finite state machines. It relies on integer linear programming to solve the constraints and reduce the state-space. The other one is based on an intentional representation and uses pure Boolean abstractions but offers no guarantee to terminate when the specification is not safe.The approach is illustrated on one simple example where the architecture plays an important role. We describe a process where the logical description of the application is progressively refined to take into account the execution platform through allocation

Executing AADL models with UML/Marte

International audienceAADL and MARTE are two modeling formalisms supporting the analysis of real-time embedded systems. Since both cover similar aspects, a clear assessment of their respective strength and weakness is required. Building on previous works, we focus here on the time aspects of the two specifications. Relying on the MARTE Time Model and the operational semantics of its companion language CCSL we attempt to equipped UML activities with the execution semantics of an AADL specification. This is part of a much broader effort to build a generic simulator for UML models with the semantics explicitly defined within the model

ANALYSIS OF FULL-WAVEFORM LIDAR DATA FOR CLASSIFICATION OF URBAN AREAS

International audienceIn contrast to conventional airborne multi-echo laser scanner systems, full-waveform (FW) lidar systems are able to record the entire emitted and backscattered signal of each laser pulse. Instead of clouds of individual 3D points, FW devices provide connected 1D profiles of the 3D scene, which contain more detailed and additional information about the structure of the illuminated surfaces. This paper is focused on the analysis of FW data in urban areas. The problem of modelling FW lidar signals is first tackled. The standard method assumes the waveform to be the superposition of signal contributions of each scattering object in such a laser beam, which are approximated by Gaussian distributions. This model is suitable in many cases, especially in vegetated terrain. However, since it is not tailored to urban waveforms, the generalized Gaussian model is selected instead here. Then, a pattern recognition method for urban area classification is proposed. A supervised method using Support Vector Machines is performed on the FW point cloud based on the parameters extracted from the post-processing step. Results show that it is possible to partition urban areas in building, vegetation, natural ground and artificial ground regions with high accuracy using only lidar waveforms

An SMT-Based Approach to the Formal Analysis of MARTE/CCSL

International audienceMARTE (abbreviated for Modeling and Analysis of Real-Time and Embedded systems) is a UML profile which provides a generalmodeling framework to design and analyze real-time embedded systems. CCSL (abbreviated for Clock Constraint Specification Language) is aformal language companion to MARTE, used to specify the constraints between the occurrences of events in real-time embedded systems. Many approaches have been proposed to the formal analysis of CCSL such as simulation and model checking. We propose in this paper an SMT-based approach to the formal analysis of CCSL. It is well-known that the SMT-based approach can effectively overcome the state-explosion problem for model checking, and can also be used for theorem proving. The latter feature allows us to prove the invalidity of CCSL constraints, which most of the existing approaches lack. We implement the proposed approach in a prototype tool clyzer on top of K framework and use Z3 as theunderlying SMT solver

MARTE: A Profile for RT/E Systems Modeling, Analysis (and Simulation?)

The original publication is available from ACM Digital Library (http://portal.acm.org/citation.cfm?id=1416222.1416271)International audienceAs its name promises, the Unified Modeling Language (UML) provides a collection of diagrammatic modeling styles. To the early class/objects and use-case diagrams were almost immediately added state-, activity-, collaboration-, and component diagrams. All these modeling views, required for structural and behavioral representations of systems, were then progressed to further detailed expressivity. Provision for domain- specific specializations was made under the form of profiles. Somehow this goal of being rather universal and extendible discarded the possibility of UML to adopt too strict and precise a semantics; as users were generally to define and refine it in their stereotyped profiles anyway. As a result, even the little execution semantics there is in the standard is often not considered in such specializations. We tackled the general issue of defining a broadly expressive Time Model as a sub-profile of the upcoming OMG Profile for Modeling and Analysis of Real-Time Embedded systems (MARTE), currently undergoing finalization at OMG. The goal is to provide a generic timed interpretation, on which timed models of computation and timed simulation semantics could be built inside the UML definition scope, instead of as part of the many external proprietary profiles. The MARTE time library can be used as the basis for the definition of a UML real-time simulator

CCSL: specifying clock constraints with UML/MARTE

The original publication is available at www.springerlink.com.International audienceThe Object Management Group (OMG) Unified Modeling Manguage (UML) profile for Modeling and Analysis of Real-Time and Embedded systems (MARTE) aims at using the general-purpose modeling language UML in the domain of Real-Time and Embedded (RTE) systems. To achieve this goal, it is absolutely required to introduce inside the mainly untimed UML an unambiguous time structure which MARTE model elements can rely on to build precise models amenable to formal analysis. The MARTE Time model has defined such a structure. We have also defined a non-normative concrete syntax called the Clock Constraint Specification Language (CCSL) to demonstrate what can be done based on this structure. This paper gives a brief overview of this syntax and its formal semantics, and shows how existing UML model elements can be used to apply this syntax in a graphical way and benefit from the semantics

Natural Interpretation of UML/MARTE Diagrams for System Requirements Specification

International audienceTo verify embedded systems early in the design stages, we need formal ways to requirements specification which can be as close as possible to natural language interpretation, away from the lower ESL/RTL levels. This paper proposes to contribute to the FSL (Formal Specification Level) by specifying natural language requirements graphically in the form of temporal patterns. Standard modeling artifacts like UML and MARTE are used to provide formal semantics of these graphical models allowing to eliminate ambiguity in specifications and automatic design verification at different abstraction levels using these patterns

Semantic Multi-View model for Low-Power

5 pagesNational audiencePower is an important concern in embedded systems. Reduction of power consumption is achieved by balancing the control of multiple domains: switching power, reducing or increasing voltage and changing the frequency on system sections. Model-Driven Engineering gives tools to model the interactions of these domains. In this work, we propose to use MARTE combined to UPF concepts to capture the structure and behavior of these multiple domains. We adopt CCSL to unify the multiform aspects among domains and to verify their proper interaction. We provide an example to illustrate MARTE representation and a simulation of multi-domain power design, specified on CCSL and running on TIMESQUARE

Multi-View Power Modeling based on UML MARTE and SysML

The development of SoC involves different activities, usually driven by specialists. These specialists use specific languages and tools to manipulate their specific concepts. The problem is that the multiple views of the system are split into different tools with redundant information. It makes it difficult to ensure consistency as well as to change from one tool to another. We propose a multi-view model where each view represents the specialist concepts in a tool-agnostic manner. The model can be kept consistent by using explicit associations instead of redundancy and tool transformation can be performed to analysis-specific tools. The approach is based on UML and two of its extensions: MARTE and SysML. It is illustrated by adding specific views to specify power management techniques. The resulting model is then transformed into a tool-specific model; \ie a model for Docea Aceplorer, a power analysis tool