The SIGNAL Approach to the Design of System Architectures

International audienceModeling plays a central role in system engineering. It significantly reduces costs and efforts in the design by providing developers with means for cheaper and more relevant experimentations. So, design choices can be assessed earlier. The use of a formalism, such as the synchronous language SIGNAL which relies on solid mathematical foundations for the modeling, allows validation. This is the aim of the methodology defined for the design of embedded systems where emphasis is put on formal techniques for verification, analysis, and code generation. This paper mainly focuses on the modeling of architecture components using SIGNAL. For illustration, we consider the modeling of a bounded FIFO queue, which is intended to be used for communication protocols. We bring out the capabilities of SIGNAL to allow specifications in an elegant way, and we check few elementary properties on the resulting model for correctness

Synchronous modeling of avionics applications using the SIGNAL language

International audienceIn this paper, we discuss a synchronous, component-based approach to the modeling of avionics applications. The specification of the components relies on the avionics standard ARINC 653 and the synchronous language SIGNAL is considered as modeling formalism. The POLYCHRONY tool-set allows for a seamless design process based on the SIGNAL model, which provides possibilities of high level specifications, verification and analysis of the specifications at very early stages of the design, and finally automatic code generation through formal transformations of these specifications. This suits the basic stringent requirements that should be met by any design environment for embedded applications in general, and avionics applications in particular

Operational Semantics of the Marte Repetitive Structure Modeling Concepts for Data-Parallel Applications Design

International audienceThis paper presents an operational semantics of the repetitive model of computation, which is the basis for the repetitive structure modeling (RSM) package defined in the standard UML Marte profile. It also deals with the semantics of an RSM extension for control-oriented design. The goal of this semantics is to serve as a formal support for i) reasoning about the behavioral properties of models specified in Marte with RSM, and ii) defining correct-by-construction model transformations for the production of executable code in a model-driven engineering framework

Operational Semantics of the Marte Repetitive Structure Modeling Concepts for Data-Parallel Applications Design

International audienceThis paper presents an operational semantics of the repetitive model of computation, which is the basis for the repetitive structure modeling (RSM) package defined in the standard UML Marte profile. It also deals with the semantics of an RSM extension for control-oriented design. The goal of this semantics is to serve as a formal support for i) reasoning about the behavioral properties of models specified in Marte with RSM, and ii) defining correct-by-construction model transformations for the production of executable code in a model-driven engineering framework

A Model for the Mixed-Design of Data-Intensive and Control-Oriented Embedded Systems

This paper presents a model and its semantics for the design of embedded systems that contain data-intensive parts such as multimedia applications, and require adaptivity w.r.t. criteria such as platform resources or quality of service (QoS). The proposed solution relies on a combination of: i) the repetitive model of computation dedicated to the design of high-performance embedded systems and ii) reactive control features based on finite state machines and modes. It is defined within a framework, called Gaspard, that implements automatic transformations that lead to various target languages, e.g., synchronous languages, SystemC, VHDL. The new model offers the adequate expressive power to describe complex behaviors of high-performance embedded systems. It also reconciles execution models dedicated to regular computations and control-oriented models that rather lead to irregular computations

Enhancing the Compilation of Synchronous Dataflow Programs with a Combined Numerical-Boolean Abstraction

RR version = http://hal.inria.fr/hal-00780521/enInternational audienceIn this paper, we propose an enhancement of the compilation of synchronous programs with a combined numerical-Boolean abstraction. While our approach applies to synchronous dataflow languages in general, here, we consider the SIGNAL language for illustration. In the new abstraction, every signal in a program is associated with a pair of the form ( clock, value ), where clock is a Boolean function and value is a Boolean or numeric function. Given the performance level reached by recent progress in Satisfiability Modulo Theory (SMT), we use an SMT solver to reason on this abstraction. Through sample examples, we show how our solution is used to determine absence of reaction captured by empty clocks; mutual exclusion captured by two or more clocks whose associated signals never occur at the same time; or hierarchical control of component activations via clock inclusion. We also show that the analysis improves the quality of the code generated automatically by a compiler, e.g., a code with smaller footprint, or a code executed more efficiently thanks to optimizations enabled by the new abstraction. The implementation of the whole approach includes a translator of synchronous programs towards the standard input format of SMT solvers, and an ad hoc SMT solver that integrates advanced functionalities to cope with the issues of interest in this wor

The Signal Synchronous Multiclock Approach to the Design of Distributed Embedded System

International audienceThis paper presents the design of distributed embedded systems using the synchronous multiclock model of the Signal language. It proposes a methodology that ensures a correct-by-construction functional implementation of these systems from high-level models. It shows the capability of the synchronous approach to apply formal techniques and tools that guarantee the reliability of the designed systems. Such a capability is necessary and highly worthy when dealing with safety-critical systems. The proposed methodology is demonstrated through a case study consisting of a simple avionic application, which aims to pragmatically help the reader to understand the manipulated formal concepts, and to apply them easily in order to solve system correctness issues encountered in practice. The application functionality is first modeled as well as its distribution on a generic hardware architecture. This relies on the endochrony and endo-isochrony properties of Signal specifications, defined previously. The considered architectures include asynchronous communication mechanisms, which are also modeled in Signal and proved to achieve message exchanges correctly. Furthermore, the synchronizability of the different parts in the resulting system is addressed after its deployment on a specific execution platform with multirate clocks. After all these steps, a distributed code can be automatically generated

Toward Static Analysis of SIGNAL Programs using Interval Techniques

International audienceThis paper presents a work-in-progress aiming at improving the functional analysis of Signal programs. The usual adopted technique relies on abstractions. Typically, in order to check the presence or absence of variables in a program at some logical instants, the program is transformed into another program that reflects its clock information so that the presence or absence of each variable can be straightforwardly checked. Signal adopts a boolean abstraction for the static functional analysis of programs. This abstraction does not enable to fully reason on the values of non logical variables. Here, we propose a solution based on interval techniques in order to be able to deal with both logical and numerical parts of programs

Tutorial: Using the UML profile for MARTE to MPSoC co-design dedicated to signal processing

International audienceThis paper demonstrates the use of a model driven design flow for Multiprocessor System on chips (MPSoCs) such as those dedicated to intensive signal processing applications. The most intensive part of these applications is usually composed of systematic signal processing followed by intensive data processing. The systematic signal processing mainly consists of a chain of filters and regular processing applied on the input signals independently of the signal values. It results in a characterization of the input signals with values of interest. The intensive data processing applies irregular computations on these values of interest. Those computations may depend on the signal values. Examples of these applications are Software Radio Receiver, Sonar Beam Forming and Multimedia video codes