Graeme Parkin

Vienna Development Method Specification Language (VDM-SL)

Abstract This paper, one of a simultaneously published set, describes the establishment in 1987 of the ISO standards project for the Vienna Development Method Specification Language (VDM-SL), and the progress of the project to the end of 1993.

Internet-Enabled Calibration: An Analysis of Different Topologies and a Comparison of Two Different Approaches

This paper discusses different network topologies used in Internet-enabled metrology and calibration and explores and compares two different remote calibration systems used by the National Metrology Institutes in England and Norway: the National Physical Laboratory (NPL) and the Justervesenet (JV). The two systems are iGen (NPL) and iMet (JV). The systems both deal with remote calibration of electrical equipment but have substantial architecture differences. In iGen, calibration procedures are downloaded from a server and then locally run at the instrument client, where the operator sits. The client is generic in such a way that it is not dependent on the structure of the measurement procedures. In iMet, two clients can communicate via a public server, and the calibration process may be remotely controlled and monitored. That is, the instruments and the operator may be separated by the Internet.

Specification of the MAA Standard in VDM

A detailed example is given of how a formal specification language has been used to specify an international banking standard on message authentication. It illustrates how a specification language can be used to specify and validate a standard.

A Dynamic Instrumentation Framework for Remote Operation of PC-Connected Devices

The authors present a dynamic instrumentation framework for remote operation of PC-connected devices. The framework is dynamic in a way such that hardware information can be downloaded and added to the system at runtime. The hardware information consists of high-level hardware drivers and the graphical user interface (GUI) components to communicate with them. The solution makes it easy to maintain the instrumentation system, and the same system may be used to operate all PC-connected devices. The system is well suited for Internet-enabled calibration

Ensuring numerical correctness using the Internet

Testing the numerical correctness of software used in metrology is necessary to establish the correctness and traceability of measurement results. Consideration is given to the way the Internet may be used to deliver mechanisms to support software testing. The mechanisms themselves depend on software and, consequently, if users are to have confidence in the results provided by the mechanisms, the software must be shown to be fit for purpose. Consideration is given to approaches to validating the software, based on publicly available guidelines.

Conformity Clause for VDM-SL

Some of the often quoted barriers to the use of formal methods have been the lack of standardised formal methods and the lack of associated tools. The Vienna Development Method Specification Language (VDM-SL) is being standardised by ISO/IEC. It has become clear from this work that we need to clarify what we mean by conformity of a specification or a tool to such standards. In this paper we define what conformity to such standards means and also highlight some of the problems that arise from this. This work is also applicable to other language standards.

SCT: building testing into standards

Strict Conformance Testing (SCT) is a methodology for testing the conformance of a security product to standards. We summarise the methodology and report on the result of our recent work applying the methodology to Secure EDIFACT. We show that SCT is useful not only in evaluating products, but also in developing and validating standards.

Complex systems proved and improved

Abstract Formal methods, the application of mathematics to the development of systems, have been promoted as bringing dramatic improvements to the quality of developed products. In practice it has been found that, although systems can be described in mathematics, going on to prove properties is too difficult and expensive. Prover technology overcomes the problems of proof, by modelling systems in propositional logic using a unique patented algorithm to do automatic proofs quickly. This technique works because the algorithm is able to exploit the fact that people design systems which they can understand and do not require hard proofs. Prover technology is briefly described showing what it can do and how it does it. Descriptions of how it is being used in the avionics and railway industries will be given.