Development of safety-critical real-time systems (original) (raw)
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Formal methods for the specification and design of real-time safety critical systems
Journal of Systems and Software, 1992
Safety critical computers increasingly a ect nearly every aspect of our lives. Computers control the planes we y on, monitor our health in hospitals and do our work in hazardous environments. Computers with software de ciencies that fail to meet stringent timing constraints have resulted in catastrophic failures. This paper surveys formal methods for specifying, designing and verifying real-time systems, so as to improve their safety and reliability.
Real Time Systems Design for Safety Critical Applications
CVR journal of science and technology, 2011
This paper studies and suggests few of the famous techniques employed in various applications in different domains, and generalise the guidelines for designing and developing Real Time Systems in safety critical applications.
Formal Analysis of Concurrent Real-Time Requirements Models
1996
This report demonstrates the use of modal and temporal logic to analysis the functional and safety requirements of concurrent real-time systems. Our research is based on the integrated method: Hazard and Operability Studies; Ward and Mellor Essential Models; and the Temporal Calculus of Communicating Systems to model and analyse real-time control systems. In particular, we discuss the interplay between traditional hazard analysis techniques and formal methods and their associated analyses in the context of an integrated model. The approach is illustrated by a small but realistic industrial case study.
A Transformational Approach to the Systematic Design of Real-Time Systems
In this paper, a bottom-up formal technique to obtain a correct system specification from the RT/SA requirements specification of a real-time system is proposed. The systematic procedure yields a complete specification in terms of CSP+T processes by means of the application of a set of transformation rules, which give a formal semantics to the semi-formal analysis entities of RT/SA. The approach takes advantage of the long tradition of RT/SA methodologies in the industry and at the same time, aims to foster the use of Process Algebras as an adequate way to overcome the intrinsic imprecision that SA presents in describing real-time systems. The method has been developed so that it may be integrated into a Software Engineering Environment, such as a CASE tool or SA-based tool. Furthermore, a formal semantics is given to the RT/SA entities in terms of CSP+T process algebra, which, by means of the new CSP-based programming libraries in Java, provides our method with the capability of au...
Science of Computer Programming, 2007
By following a methodological approach, introduced in a previous work, a correct system specification in terms of CSP+T process algebra is systematically obtained from the UML-RT model of a real-time software system. Among other contributions, this article aims at integrating collaboration diagrams into our approach to facilitate the specification of capsules in UML-RT design models. Thus, an improved systematic transformation procedure to derive a correct and complete formal system specification of real-time systems is established here. Temporal requirements integration in the design and system specification stages of a real-time system is also addressed, so that the approach now opens up the possibility to carry out scheduling and dependability analysis at the design phase of the system development life cycle for hard real-time systems. The article also discusses a practical application to present a systematic transformation from a UML-RT model of a well known manufacturing-industry paradigmatic case, the "Production Cell".
Proceedings of the Eighth International Conference on Enterprise Information Systems
The systematic translation from a UML/RT model into CSP+T specifications, proposed in a previous paper, may give a way to use jointly UML and CSP in a unified, practical and rigorous software development method for real-time systems. We present here a systematic transformation method to derive a correct system specification in terms of CSP+T from a semi-formal system requirement specification (UML-RT), by applying a set of transformation rules which give a formal semantics to the semi-formal analysis entities of UML/RT, and thus open up the possibility of verifying a software system design that also includes realtime constraints. As to show the applicability of the approach, a correct design of a real-time system is obtained by following the process of development proposed here.
Technical Report SBU-CISM-01-03, 2001
Formal methods are usually used for computer system specification, production and verification. In this paper, a new direction for the use of formal methods is proposed, namely formalization of the regulatory requirements for software of safety-critical real-time control systems. Formal regulatory requirements, as opposed to formal specifications for a concrete system, have a generic nature, are applied for a wide range of safety-critical control systems, and are the basis for a licensing process. The use of formal regulatory requirements could help to eliminate ambiguity or misunderstanding of informal definitions, to allow rigorous assessment of satisfaction with respect to requirements and finally to increase the safety level of a system. As a formal method for describing the regulatory requirements, the Z notation is proposed. To demonstrate the proposed approach, requirements for protection against common mode software failures and requirements for protection against unauthorized access are considered. Z schemas for these requirements are presented.
Formal specification of real-time systems by transformation of UML-RT design models
Proceedings of the …, 2006
We are motivated to complement our methodology by integrating collaboration diagrams to facilitate the specification of capsules in UML-RT design models. An improved systematic transformation method to derive a correct and complete formal system specification of real-time systems is established. This article aims at integrating temporal requirements in the design stage of the life cycle of a real-time system, so that scheduling and dependability analysis can be performed at this stage. The application of CSP+T process algebra to carry out a systematic transformation from a UML-RT model of a well known manufacturing-industry paradigmatic case, the "Production-Cell", is also presented.
Correct development of Real-time systems IST-2001-33522
2005
Abstract. Constructing a program from a specification is a long-known general and fundamental problem. Besides its theoretical interest, this question also has practical implications, since finding good synthesis algorithms could bring about a major improvement in the reliable development of complex systems. In this paper we describe a methodology for synthesizing statechart models from scenario-based requirements.
Formal specification languages for real-time systems
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.