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Safety Critical Software in Vehicle and Traffic Control, IEE Colloquium on

Date 13 Feb 1990

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  • Safety critical software in traffic control systems

    Page(s): 2/1 - 2/5
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (272 KB)  

    Because of the safety implications, certain conditions in road traffic signal systems must be avoided, and it is not acceptable for them to be discovered once the system is in use. The article identifies relevant factors. First, all potential hazards must be identified. The specification needs rigorous analysis; the specifier may be unaware of the types of problems arising in software. Formal methods of testing and analysis are considered. The use of tools in software development, and particularly for detecting unforeseen consequences of apparently slight changes in software, is discussed View full abstract»

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  • Vehicle control systems-reliability through simplicity

    Page(s): 3/1 - 310
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (348 KB)  

    Vehicle electronic control systems have the potential to become unreliable when they grow too complex. By careful design of the whole system, both hardware and software, it is possible to organise the data processing tasks in such a way that the risks associated with software failure are indeed minimal. The validation tools already in widespread use throughout the industry, when rigorously applied, reduce this risk to below that associated with hardware design failures. The paper concerns the programmable automotive microcontroller (PAM), an ASIC-based device developed by AB Automotive Electronics to improve reliability. It describes ways in which PAM can detect errors arising from various sources in software. AB has written, and maintains, its own compiler for PAM. The compiler gives warnings of possible sources of difficulty. Standards for software and the development thereof are given View full abstract»

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  • On the development of a high quality software design methodology for automotive applications

    Page(s): 6/1 - 6/5
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    Microprocessor systems are beginning to be used in a variety of safety-critical applications in the automotive industry. Throttle, brake and steering systems are changing from mechanically controlled systems to electrical systems. Thus there is a need for safe and reliable actuators and controllers. The issue of reliability should be considered by the customer from a system viewpoint, since it is affected by both hardware and software. There already exist stringent standards for hardware design, such as the German TUV standard, but there remains a need for rigorous standards to produce more reliable software. A systematic approach to software design throughout its lifecycle is presented. Particular emphasis is paid to software documentation and maintenance. To assist various phases of the design process, a set of guidelines which are invoked for the development of safety-related systems are introduced in order to assist various phases of the design process View full abstract»

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  • Design for safety

    Page(s): 1/1 - 1/4
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (160 KB)  

    Developers coming into safety-related projects for the first time are particularly seeding guidance in microprocessor-based electronics, where the designer has previously been concerned primarily with exacting the most economic utilisation from the minimum component count. This paper summarises some important considerations in design of a safety-related microprocessor-based system. It considers preliminary hazard analysis, requirements specification, the conflict between safety and reliability, safety evaluation techniques and design for assessment View full abstract»

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  • Introduction of new methods for assuring safety into the software development process

    Page(s): 5/1 - 5/2
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    Discusses how, without significant retraining, software engineers can adopt techniques to ensure the safety of safety-critical software. It is suggested that one or more specialists in a chosen real-time structured analysis or design technique work with the project team, using the technique in the project, and thereby demonstrate its effectiveness, and incidentally identify its weaknesses for subsequent improvement View full abstract»

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  • IEE Colloquium on `Safety Critical Software in Vehicle and Traffic Control' (Digest No.031)

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    The following topics were dealt with: microprocessor design for safety; traffic signal software development; reliability through simplicity; system architectures; safety assurance methods; road transport informatics; and formal methods in software development View full abstract»

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  • The role of formal methods in developing safety-critical software

    Page(s): 9/1 - 9/3
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    Formal methods use the rigour of mathematics to strengthen the process of software development, leading to lower risk, higher quality and better control of costs and timescales. The use of these methods is growing and practical experience is already quite widespread. Nevertheless, several fallacies still surround formal methods-for example that they are primarily for proving that programs are correct, that they involve complex mathematics, that they increase the cost of development, and that they are incomprehensible to clients. Belief in these fallacies inhibits more widespread use of formal methods by engineers, which damages companies commercially and probably reduces system safety. The article describes the characteristics of the methods, refutes some fallacies, and describes projects in vehicle and traffic control View full abstract»

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  • System architectures for safety critical automotive applications

    Page(s): 4/1 - 4/3
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (180 KB)  

    As vehicle electronic control systems increase in both complexity and control authority there must be a commensurate increase in our ability to design and implement these systems safely. Sources of failure are described, and architectures for systems with and without a safe state are discussed. The use of common specifications, hardware and software are all seen as hazardous for very high integrity systems. Diversity is regarded as the best approach for providing the safety levels required and the preferred approach is to provide this by utilising checking and back-up systems which are designed against a different requirement, and have less functionality than the main control system. In this way the integrity of these systems can be kept high at a reasonable cost View full abstract»

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  • The design of distributed safety critical software using CSP

    Page(s): 8/1 - 8/5
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (228 KB)  

    Generally speaking, traffic control systems using signals are basically complex distributed control systems. These large-scale systems and networks are made up from interacting hierarchically structured subsystems. In order to control such highly complex systems, conventional mechanisms have become inefficient and impractical. The reliance on sophisticated computer control systems to manage such systems and networks is now becoming increasingly essential in order to match with ever growing demands and needs. As the traveling public are the primary clients of these systems, their safety must be ensured. In order to design and develop such safety critical software with high degree of correctness, a systematic and logical method is therefore necessary. This paper presents the use of the formal system Communicating Sequential Processes (CSP) with a complementary CSP interpreter as powerful toolset. CSP provides a model not only for the separate discrete event processes which constitute the system, but also for the interactions among them. The CSP interpreter provides an automatic tool for specifications written in CSP. These tools can be efficaciously applied by control and software engineers to initiate their designs, especially in the early stage of software development where ideas have to be tested out efficiently for their correctness and feasibility View full abstract»

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  • DRIVE project V1051-procedure for safety submissions for road transport informatics

    Page(s): 7/1 - 7/4
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    This paper discusses the on-going movement towards common standards and harmonisation in the application of information technology to European road transport systems, particularly the work of Project V1051, Procedure for Safety Submissions for Road Transport Informatics, in the DRIVE programme. The programme exists because it is expected that the widespread use of computer systems to vehicles and in traffic management systems will provide the mechanism on which to base a viable solution to current and foreseeable problems. A major assumption that has influenced the direction of DRIVE is the idea that whereas there appears to be unlimited demand to use the road networks, there is a limit to the number of new roads that can be built. The resolution of this dichotomy is seen in the proposed provision of effective information systems, navigation systems and dynamic traffic management systems. Within these three areas the following ideas are being seriously considered; the use of artificial intelligence and expert systems, automatic or semi-automatic vehicle control systems, lane and positioning control and collision avoidance systems, and road usage and access control View full abstract»

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