STRUCTURAL-ENGINEERING AND SOFTWARE - CERTAINTY, UNCERTAINTY AND PROBABILITY

The design of any engineering artefact for use in a safety critical ap plication should be subject to safety analysis; this applies inter ali a to physical structures and software. It is often stated that softwar e is different to other engineered artefacts because it does not degra de in any physical sense, with use or the passage of time, and it is p rone to design error much more than physical systems, as much of the c omplexity in a system often 'resides' in the software. However, in ass essing software and physical structures one has certainty on some issu es, but there is a need to deal with probability and uncertainty with regard to others. The aim of this paper is to draw out the analogies a nd distinctions between the software and structural engineering discip lines, focusing on certainty, uncertainty and probability in the asses sment process.