P. L. Guernic, T. Gautier, M. L. Borgne, and C. de Marie. Programming real-time applications with SIGNAL. Proceedings of the IEEE, 79(9):1321-- 1335, September 1991.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....specification may have zero solutions, one solution or multiple solutions. Though an implementation of a system usually demands a unique solution, other solutions may be interesting for high level specifications. The relation based approach has been employed in the synchronous language Signal [39]. VHDL defines the data type boolean by means of type boolean is (false, true) At program start variables and signals take the leftmost value of their data type definitions, in case of the boolean data type the value false. ForSyDe defines process networks as a set of equations. To date ....

....such as if then else, Esterel has a large number of preemption statements that allow the termination of statements. There is a formal framework developed for Esterel, which includes causality analysis ensuring that causality constraints are never contradictory in any reachable state. A Signal [39] program is a specification of constraints or relations on the involved signals. The Signal compiler performs formal calculations on synchronization, logic, and data dependencies to check program correctness and produce executable code. Signal is a declarative data flow language and supports ....

P. L. Guernic, T. Gautier, M. L. Borgne, and C. de Marie. Programming real-time applications with SIGNAL. Proceedings of the IEEE, 79(9):1321-- 1335, September 1991.

....and its actual completion . Asynchronous languages are well suited to describing transformational and interactive systems but are often not so appropriate where reactive systems are concerned [21] The most notable examples of synchronous languages are Esterel [24] Lustre [62] Signal [59] and Statecharts [65] Lustre and Signal are declarative languages which are designed with realtime DSP systems in mind. In contrast Esterel and Statecharts are imperative languages which focus instead on describing real time controllers. Although the problem domains are varied, the common factor ....

GUERNIC, P. L., BORGNE, M. L., GAUTIER, T., AND MAIRE, C. L. Programming real time applications with Signal. Proceedings of the IEEE 79 (September 1991), 1321--1336.

....conditional equational logic [4] with time. Our approach is new and departs from the proposals already made in order to add time into (constraints) logic languages such as tcc [14] Templog [1] and Chronolog [16] Roughly speaking, timed programs are provided, as in synchronous languages, e.g. [8], with a canonical signal or clock, noted Sref which serves as a reference for other possible user de ned or input signals. In general, operator de nitions within a program P may depend on time. Thus, at each instant t, of Sref, a new store consisting of operator de nitions is updated in the same ....

.... sorted family of timed operators. S stands for the set of non empty strings over S. We assume that S contains at least the sort of booleans, bool, and the sort of naturals, nat. The meaning of a signal in our approach is very close to the ones introduced in some synchronous languages, e.g. [8, 5]. A signal s of sort s 1 ; s n ; s, noted s : s 1 ; s n s is a stream of operator denotations. These denotations are associated implicitly to some instants over time. These instants constitute a set called ticks of s. Hence, our notion of time is linear and multi form. Every ....

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P. L. Guernic, T. Gautier, M. L. Borgne, and C. L. Maire. Programming real time applications with signal. Proceedings of the IEEE, 79(9), 1991.

....all this is performed on sound formal bases. The analysis and verification techniques handle 2 the logical time aspects of discrete event systems. Synchronous languages A family of languages is based on the synchronous hypothesis, featuring among others Esterel [6] Lustre [7] and Signal [8]. In Statecharts [9] the semantics of parallelism (called orthogonality) is consistent with the synchronous parallel composition. These languages all have complete environments, with sets of tools based upon their formal semantics, and which support specification, formal verification, ....

....and its languages are available commercially, and applied in industrial contexts [10] Parallelly, research is going on as well as experiments on new features, such as the experiment reported in this paper. Among synchronous languages, Signal is a real time synchronized data flow language [8]. Its model of time is based on instants, and its actions are performed within the instants. SignalGT is an extension that introduces intervals of time, and provides constructs for the specification of hierarchical preemptive tasks executed on these intervals [11] this way, it offers a ....

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P. Le Guernic, M. Le Borgne, T. Gautier, and C. Le Maire. Programming real time application with Signal. Proc. of the IEEE, 79(9):1321--1336, September 1991.

.... 1 E = 0 P = 0 Motor is bad Motor = Off Motor = On P = E = 0 Motor = On P = 1, E = 0 Motor = Off E is broken Motor = Off P = E = 1 Motor = On P = 0, E = 1 Motor = Off P is broken Figure 2: Automaton for a paper tray with failure modes The class of synchronous languages [BG92,HCP91,GBGM91,Har87] have the following features: Perfect Synchrony: Program combinators are determinate primitives that respond instantaneously to input. Output at time t is a function of the input at time up to t; at any instant the presence and the absence of signals can be detected. Bounded State: ....

P. Le Guernic, M. Le Borgne, T. Gauthier, and C. Le Maire. Programming real time applications with signal. In Special issue on Another Look at Realtime Systems, Proceedings of the IEEE, September 1991. REFERENCES 67

....the Hierarchical Conditional Dependency Graph (HCDG) It is a special kind of directed graph that represents data and control dependencies from a data flow perspective. Historically, it has been developed as internal representation of synchronous programs written in the SIGNAL programming language [9], used for the specification of reactive, real time systems. This internal representation is an aggregation of two objects: the Conditional Dependency Graph (CDG) and the Clock Hierarchy (CH) The CH will be connected to the CCFG by linking each conditional predicate in the input description to ....

P. Le Guernic, M. Le Borgne, T. Gautier, C. Le Maire, "Programming Real Time Applications with SIGNAL", Proc. of the IEEE, vol.79, no.9, pp. 1321-1336, Sep. 1991

....the determinism of the specified systems, and supports techniques for formal verification (like the detection of causality cycles and logical incoherences) A family of languages is based on this approach [14] featuring Esterel, Lustre, Signal, Argos and also Statecharts. Among them, Signal [18] is a data flow language, with a declarative style: processes are systems of equations on values and their occurrence instants. The compiler transforms the specification into an optimized executable code (in C, Fortran or Ada) computing and outputting the solutions to this system of equations at ....

....preceding characteristics. 5 Nested preemption of reactive data flow tasks: SignalGT 5. 1 The synchronous reactive data flow language Signal As said in Section 1, Signal is a synchronous real time language, data flow oriented (i.e. declarative) and built around a minimal kernel of operators [18]. It manipulates signals, which are unbounded series of typed values (integer, logical, They have an associated clock determining the instants where values are present. For instance, a signal X denotes the sequence (x t ) t2IN of data indexed by time index t. Signals of a special kind called ....

P. Le Guernic, M. Le Borgne, T. Gautier, and C. Le Maire. Programming real time application with Signal. Proceedings of the IEEE, 79(9):1321--1336, September 1991.

....like SIGNAL, with a facility to safely and accurately compute WCET bounds and thus enable the designer of R T applications, reason about the correctness of both functional and temporal properties at a high abstraction level. 2 Introduction to SIGNAL SIGNAL is a dataflow oriented language [6] based on the synchrony hypothesis[7] It belongs to the family of synchronous languages [8] and it is used for the functional specification of reactive R T systems for control and DSP applications. Using the language expressions the user is programming in an equational style and thus each program ....

....it is used for the functional specification of reactive R T systems for control and DSP applications. Using the language expressions the user is programming in an equational style and thus each program is a system of equations. The SIGNAL compiler resolves these systems and performs checks (see [6][10] useful in discovering possible sources of error. Around the SIGNAL language and its compiler exists a variety of tools like a Graphical User Interface for program entry, code generators (C, Fortran, VHDL[9] and intermediate code genera tors to access formal verification and other ....

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Paul Le Guernic, Michel Le Borgne, Thierry Gautier, Claude Le Maire, "Programming Real Time Applications with SIGNAL", Proceedings of the IEEE, vol.79, no.9, pp. 1321-1336, Sep. 1991.

....input, the instant at which u is read is not : reading of the input is on demand driven mode. This is reflected by the fact that inputs of this sts are the pair factivation clock h, value of u when it is presentg. Using these primitives, dataflow synchronous languages such as Lustre [13] Signal [16], and Statecharts [21] are easily encoded. Open environments and modularity. As modularity is wanted, it is desirable that the pace of an sts is local to it rather than global. Since any sts is subject to further composition in some yet unknown environment, this makes the requirement of having a ....

P. Le Guernic, T. Gautier, M. Le Borgne, C. Le Maire, "Programming real-time applications with Signal", Another look at real-time programming, special section of Proc. of the IEEE, vol. 9 n o 9, September 1991, 1321--1336.

....the Hierarchical Conditional Dependency Graph (HCDG) It is a kind of directed graph that represents both data and control dependencies from a data flow perspective. Historically, it has been developed as internal representation of synchronous programs written in the SIGNAL programming language [13], used for the specification of reactive systems. An HCDG is the aggregation of two objects: the Conditional Dependency Graph (CDG) and the Clock Hierarchy (CH) It consists of nodes and edges labeled by clocks. Each node corresponds to an operation that assigns a value to a variable. Clocks are ....

P. Le Guernic, M. Le Borgne, T. Gautier, C. Le Maire, "Programming Real Time Applications with SIGNAL", Proc. of the IEEE, vol.79, no.9, pp. 1321-1336, Sep. 1991

....CVFP (Osys) 11 11 28 17 Splicer 24 9 43 CAPSYS 21 4 15 HAL 12 6 26 20 SE 11 9 25 16 ELF 11 11 30 SPAID 19 17 Table 1: Comparison of Osys performance on the elliptic filter with other tools [7] results not available) 6 4.2 SIGNAL 4.2. 1 The language The Signal language [19] was developed at IRISA Rennes to design and implement real time systems. The basic object handled by Signal is a possibly infinite sequence (or a stream) of values called a signal. A Signal process is a set of relations (equations) between signals, specifying both constraints on their values and ....

P. Le Guernic, Th. Gautier, M. Le Borgne, and C. Le Maire. Programming real-time applications with signal. Proceedings of the IEEE, 79(9):1321--1336, September 1991.

....approach guarantees the determinism of the specified systems, and supports techniques for the detection of causality cycles and logical incoherences. A family of languages is based on this approach [5] featuring amongst other Esterel, Lustre, Signal and also Statecharts. Among them, Signal [6] is a data flow language, with a declarative style: processes are systems of equations. The compiler transforms the specification into an optimized executable code (in C or Fortran) Verification of dynamical properties is based on polynomial dynamic systems over ZZ= 3ZZ . SignalGT is a ....

....series of activation intervals found in the application. Then Section 4 describes the detailed specification of the confirmation phase, and just a brief account of the rest of the controller for the sake of brevity. p. 2 3. The synchronous language Signal The Signal equational language. Signal [6] is built around a minimal kernel of operators. It manipulates signals X, which denote unbounded series of typed values (x t ) t2T , indexed by time t in a time domain T . An associated clock determines the set of instants at which values are present. A particular type of signals called event is ....

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P. Le Guernic, M. Le Borgne, T. Gautier, and C. Le Maire. Programming real time application with signal. Proc. of the IEEE, 79(9):1321--1336, September 1991.

....of timing information, or the absence thereof, and the ability to define mixed systems over infinite time intervals. These two features are already present in the previously introduced Signalea language [3] which represents an an extension of the Signal synchronous real time language [22, 5, 4]. The Signalea language generalizes stochastic Buchi automata, Petri nets, and our Sig minilanguage. But the mathematical foundations of Signalea in [3] are somewhat shaky and estimation is not included. Thus, generalizing CSS to Signalea is a high priority task, particularly since Signalea is ....

P. Le Guernic, T. Gauthier, M. Le Borgne, and C. Le Maire, Programming real-time applications with Signal, Proc. IEEE, 79 (1991), pp. 1321--1336.

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P. Le Guernic, T. Gautier, M. Le Borgne, C. Le Maire, "Programming real-time applications with Signal", Another look at real-time programming, special section of Proceedings of the IEEE, vol. 79, n o 9, September 1991, 1321--1336.

....example The motivations for choosing Statecharts for our example are the following. First, Statecharts are a widely known and visual formalism [16] And, second, we wish to convince the reader that our technique for distributing synchronous programs extends beyond our own Signal formalism [20], and even beyond the french synchronous Esterel [9] and Lustre [14, 15] The Statecharts example shown in figure 1 will support our discussion throughout this paper. The Statecharts has four and states working in parallel : an arbiter, an emitter, and a out p 1 bit # 2 bit # h a a a a ....

P. Le Guernic, T. Gautier, M. Le Borgne, and Le Maire C. Programming real-time applications with SIGNAL. Another look at real-time programming, special section of Proc. of the IEEE, 79(9):1321--1336, September 1991.

....CFSM (Codesign Finite State Machines) as a model for synchronous machines which can be desynchronized; this can be seen as a refinement of [13] although the referred model of asynchrony is not fully stated. Independently, another approach relating synchrony and asynchrony has been followed. In [7, 18] it is shown how nondeterministic Signal programs can be used to model asynchronous communication media such as queues and buffers. Reactive Modules [1] were proposed as a synchronous language for hardware modeling, in which asynchrony is emulated by the way of nondeterminism. Although this is of ....

P. Le Guernic, T. Gautier, M. Le Borgne, and Le Maire C. Programming real-time applications with SIGNAL. Another look at real-time programming, special section of Proc. of the IEEE, 79(9):1321--1336, September 1991.

....these problems there are the automatic partitioning into hardware and software, the synthesis of hardware and the generation of optimal code for software implementation. The work presented in this paper is part of a more general effort for building a hybrid framework in which the Signal [12] [13] and Alpha [20] languages can be used for real time system codesign. 1.2 Cospecification and Cosimulation of Signal Alpha Systems Signal is a synchronous [4] language developed for the specification, validation and implementation of real time systems. Signal variables represent finite or ....

Le Guernic P., Gautier T., Le Borgne M., Le Maire C.: "Programming Real-time Applications with Signal", Proceedings of the IEEE, September 1991, 79, (9), pp. 1321-1336

....a system are instantaneous; 2. Two or more actions can take place at the same instant (they are simultaneous) Thus, from the point of view of the temporal properties of a system, only succession and simultaneity of instants are of interest, their exact time values have no signification. Signal [3] is a synchronous language developed for the specification, validation and implementation of real time systems. Due to the synchronous approach, the verification of the logical properties of an application is possible before considering the physical properties of a particular implementation. The ....

.... the abstraction of the specification from the details of a given implementation, offering the possibility to verify logical properties and to guarantee the functional safety of an application [2] Moreover, programming in Signal consists simply of writing systems of equations on program variables [3]. The Signal compiler resolves these systems and verifies thus the correctness of the program. A variety of tools exist around the Signal language and its compiler; among these, a Graphical User Interface for high level system design [17] and a C code generator for functional simulation. The ....

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Le Guernic, P., Le Borgne, M., Gautier, T., Le Maire, C.: Programming real-time applications with Signal. Technical Report 1446, INRIA, France (June 1991)

....of a discrete logical time, the synchronous languages [1] Signal, Lustre [2] Esterel [3] have proved their efficiency for the design of critical and safe real time applications. They are characterized by strong semantics that allow the programmer to use verification and proof techniques. Signal [4], one of the synchronous languages, is declarative and data flow oriented. In this language, a signal is a sequence of values; the instants of presence of the signal are called clocks. The Signal compiler [5] is a formal system able to solve equations and to reason upon logic. All along the ....

Paul Le Guernic, Thierry Gautier, Michel Le Borgne, and Claude Le Maire. Programming real-time applications with Signal. Proceedings of the IEEE, 79(9):1321--1336, septembre 1991.

....study. 1 Introduction This paper presents a formal method for the verification of reactive real time systems and its application to the case study of the controller of a power transformer station. The specification of the controller is made in the real time synchronized data flow language Signal[10]. Its declarative style is based on equations defining the values and the synchronizations of flows of data called signals. Schematically, processes are systems of equations, and the compilation of a Signal program involves transforming the specification into an executable code solving this system ....

....code solving this system of equations at each reaction. Compilation performs the checking of the causal and temporal consistency of the specification. Some statical properties can thus be proved by the compiler (this part of the verification is only briefly mentioned in this paper; see [2] and [10] for details) The original equational nature of Signal makes that it relies on a formal model in terms of polynomial dynamical equations systems, and the proof method is based on the theory of algebraic geometry. This way, it is possible to prove a wide variety of dynamical properties, such as ....

[Article contains additional citation context not shown here]

P. Le Guernic, M. Le Borgne, T. Gautier, and C. Le Maire. -- Programming real time application with signal. -- Proc. of the IEEE, 79(9):1321--1336, September 1991.

....so as to support automated assistance tools, while not introducing undue unpredictability in composition and tasking. The synchronous approach to reactive systems addresses this problem specifically, in the form of programming languages and environments amongst which the data flow language Signal (Le Guernic e.a. 1989), and also Esterel, Lustre, Argos (Halbwachs, 1993) and StateCharts (Harel, 1987) They offer tools based on a formal model of reactive systems for e.g. analysis, verification, evaluation, and code generation. A characteristic feature of the synchronous models is the synchronous composition. It ....

....to go from the original (possibly partial) specification to final (possibly distributed) implementation. Various experiments have been performed with Signal and the methodology associated to its use, some made in cooperation with industrial partners. Among them were systems for speech recognition (Le Guernic e.a. 1989), digital watch control (Gautier e.a. 1994) active vision in robotics (Marchand, E. e.a. 1996) the control of a production cell (In Lewerentz e.a. 1995) the control of an electrical power transformer station (Marchand, H. e.a. 1995) and behavioural animation in computer graphics. This ....

[Article contains additional citation context not shown here]

Le Guernic, P., Le Borgne, M., Gautier, T. and Le Maire, C. (1989) Programming real time application with Signal. Proc. of the IEEE, 79(9), pp. 1321--1336.

....input, the instant at which u is read is not: reading of the input is on demand driven mode. This is reflected by the fact that inputs of this sts are the pair factivation clock h, value of u when it is presentg. Using these primitives, dataflow synchronous languages such as Lustre [9] and Signal [13] are easily encoded. Statecharts [10] are encoded too [2, 3] Open environments and modularity. As modularity is wanted, it is desirable that the pace of an sts is local to it rather than global. Since any sts is subject to further composition in some yet unknown environment, this makes the ....

P. Le Guernic, T. Gautier, M. Le Borgne, C. Le Maire, "Programming real-time applications with Signal", Another look at real-time programming, special section of Proc. of the IEEE, vol. 9, n o 9, September 1991, 1321--1336.

....applications become more and more demanding in terms of safety, complexity, flexibility, modularity, integrability, etc. a new concept for real time programming has emerged these last few years: the synchronous programming. The so called synchronous languages Esterel [7] Lustre [12] and Signal [14] are the pillars of synchronous programming, but other formalisms such as the Statecharts [13] are also closely related. From the user s point of view, the main characteristics of these languages are the following: ffl a precise mathematical semantics, ffl precise notions of modularity and ....

....are generic so that nodes can be configured to be attached to local menus, responding to actions on the graph. In the future, new features will be added to the existing ones: multi windowing, editing (copy cut paste) operations, PostScript output, etc. 4. 3 A brief introduction to Signal Signal [14] is a synchronous real time language, data flow oriented and built around a minimal kernel. It manipulates signals, which are unbounded series of typed values, with an implicit associated clock denoting the instants when values are present. For instance, a signal X denotes the sequence (x t ) ....

Paul Le Guernic, Thierry Gautier, Michel Le Borgne, and Claude Le Maire. Programming real-time applications with Signal. Proceedings of the IEEE, 79(9):1321--1336, septembre 1991.

No context found.

P. L. Guernic, T. Gautier, M. L. Borgne, and C. L. Maire, Programming real-time applications with Signal, Proceedings of the IEEE, 79 (1991), pp. 1321--1336.

No context found.

P. L. Guernic, T. Gautier, M. L. Borgne, and C. L. Maire, Programming real-time applications with Signal, Proceedings of the IEEE, 79 (1991), pp. 1321-- 1336.

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