Knowledge engineering in the communication of Information for safety critical systems

Abstract

The design and assessment of safety critical systems often involves broad and distributed teams of designers, suppliers and analysts who represent diverse areas of expertise and motivations. Accurate and effective communication between these groups is therefore an issue of primary importance. The formalisation of specifications and arguments of safety can be of significant benefit in ensuring the consistency of evidence in such cases, when it must be presented across many domains. However, a formal description of a safety critical system may be unconvincing unless it is presented in a form which is (or forms which are) accessible to the broad range of users and assessors of safety cases. This raises issues of human communication which include the tailoring of information to particular communicative tasks; the efficacy of differing media for communication and the cognitive impact that such differing media have. This paper draws together work in fields of knowledge engineering, knowledge based systems and human communication in an effort to address, from a sound theoretical basis, these and other communication issues raised by the use of formal descriptions in safety critical systems. Further, this paper argues that a primary role for knowledge based systems techniques in safety critical systems is in supporting the communication of information.

Argument Representation for Dependable Computer-Based Systems

“…This is to say, the object language and meta-framework we propose offers a sufficiently expressive form of representing dependability arguments, but a formal description of such an argument may be confusing or unconvincing unless it is presented in a form which is (or forms which are) accessible to the broad range of reviewers who must assess it. This issue, as it relates specifically to dependability arguments for safety-critical systems, is discussed at length in (Gurr 1997). A conclusion of that discussion is that salient and accessible presentations of the high-level structure of dependability arguments, such as those which the diagrammatic ASCE and GSN notations reviewed in Section 2 seek to capture, are an essential part of an effective argument representation.…”