Specification of Realtime Systems

IEEE Transactions on Software Engineering, 1997

ASTRAL is a formal specification language for realtime systems. It is intended to support formal software development and, therefore, has been formally defined. The structuring mechanisms in ASTRAL allow one to build modularized specifications of complex systems with layering. A realtime system is modeled by a collection of state machine specifications and a single global specification. This paper discusses the rationale of ASTRAL's design. ASTRAL's specification style is illustrated by discussing a telephony example. Composability of one or more ASTRAL system specifications is also discussed by the introduction of a composition section, which provides the needed information to combine two or more ASTRAL system specifications.

2010 International Symposium on Information Technology, 2010

This paper presents a survey about the formal specification languages which are used to specify Real-time systems. Real time systems are critical systems such as nuclear missile system, auto pilot system etc. A minor fault in these systems can result into serious consequences. These consequences may comprise threat to human life. Therefore it is very vital to specify the system correctly. To achieve the correct and unambiguous specification, formal languages are used. Formal languages increase the confidence on the specification and hence the overall system. This paper compares formal languages which are used to specify real-time systems such as VDM++, RTSJ, ASTRAL. A comparison criterion is established to select the best suitable specification languages for Real-Time systems. In the end a small example is mapped in to three selected specification languages which conclude that which language provides the best constructs and tools for Real-Time systems.

Proc. 8'th EuroMicro Workshop on Real Time Systems, 1996

A new formal method for the specification, of real-time system requirements and their refinement to a design architecture is set out here. This integrated method is derived from a recently developed formal semantics, logic and refinement calculus for the IEEE standard hardware specification language VHDL. The specification format consists of three-phase “before, during and after” logical schemas, and comes with a combinatorial schema calculus and a refinement theory. The look and feel is reminiscent of Z and VDM and is intended to present an “upgrade path” to real-time for users with specification skills in these languages

Lecture Notes in Computer Science, 1991

ASTRAL is a formal specification language for realtime systems. This paper discusses the rationale of ASTRAL's design and shows how the language builds on previous language experiments. ASTRAL is intended to support formal software development; therefore, the language itself has been formally defined. ASTRAL's specification style is illustrated by discussing a case study taken from telephony.

This paper presents a survey about the formal specification languages which are used to specify Real-time systems. Real time systems are critical systems such as nuclear missile system, auto pilot system etc. A minor fault in these systems can result into serious consequences. These consequences may comprise threat to human life. Therefore it is very vital to specify the system correctly. To achieve the correct and unambiguous specification, formal languages are used. Formal languages increase the confidence on the specification and hence the overall system. This paper compares formal languages which are used to specify real-time systems such as VDM++, RTSJ, ASTRAL. A comparison criterion is established to select the best suitable specification languages for Real-Time systems. In the end a small example is mapped in to three selected specification languages which conclude that which language provides the best constructs and tools for Real-Time systems.

requirements for high quality specifications of real-time systems are stated. An approach based on the integration of logic and object-oriented formalisms is advocated and the essential features of a language-named TRIO +that exploits such an approach are described. It is also argued that the benefits of the use of rigorous approaches to the system specification phase can be highly enhanced by suitable CASE tools that support the whole process. Early experiences on the application of the TRIO + language and of its tools to industrial problems are reported.

A specification language for real-time software systems is presented. Notions from Category Theory are used to specify how the components of a system should interact. The potential role of the proposed language in the search for interoperability of specification formalisms is briefly discussed.

2002

The specification of complex systems, such as software, requires welldefined languages and methods. In the case of real-time systems, where temporal correctness must be achieved in addition to functional, descriptions of time dependant behaviour must be expressable within the specification language.

1996

Abstract Formal methods are being increasingly used in engineering industrial software. They are mostly used for specifying and verifying software requirements, but seldom in later development phases. This paper tries to bridge the gap between formal requirements specification and final code by introducing a formally defined design notation. The proposed design notation extends structured analysis specification notations with constructs derived from POSIX real-time extensions.

Increasingly complex systems are being designed that consist of concurrently operating and communicating processes, often combining both hardware and software. A methodology for high level specification and design of software/ hardware systems (SHE [1]) has been designed to cope with this increasing complexity. SHE incorporates a formal specification language named POOSL. Many systems today can be characterised as real-time. The timing properties of such a realtime system determine the correctness of an implementation. This paper describes the extension of the language POOSL with a notion of time and with real-time primitives, which enable it to specify and model timing properties. Concepts and aspects related to timing and concurrency are discussed and options for introducing time and adding temporal meaning to existing elements of the language are investigated. The language POOSL and its formal semantics have been extended with a notion of time and a new primitive has been added. It is shown that this extension enables the expression of typical forms of temporal behaviour such as execution time, time-out behaviour, etcetera. POOSL can thus be used as a formal basis for specifying and designing real-time systems within the SHE methodology.