Interdisciplinary Design and Evaluation of Dependability

Principal Investigator:

Robin Williams

Funding:

This project was funded by EPSRC.


Overview

Computers increasingly play vital roles in organisations - e.g., hospitals or factories - which thus become "computer-based systems". The dependability of these systems is a major societal concern. In response, EPSRC funded the Dependability Interdisciplinary Research Collaboration (DIRC) between City, Edinburgh, Lancaster, Newcastle and York universities. DIRC was based on the premise that dependability must be studied not as a purely technical issue, but as a socio-technical property of the combination of a computing system with the environments in which it is procured, developed and used. DIRC thus assembled a world class interdisciplinary team of computer scientists, psychologists, sociologists and statisticians, which has achieved substantial results through a rare degree of collaboration between engineering and social sciences.

INDEED will build on DIRC's results to address important challenges in extending these results and combining them with current practices, to ensure a real, long-term impact on the design and evaluation of dependable systems. It will apply a multidisciplinary approach in four major research activities:

Timing and Structure

This work will further develop DIRC's "time band" concept for reasoning about processes that unfold on different time scales, from microseconds to days, within a system. We will define an appropriate descriptive language, and extend it to deal with probabilistic relationships between events in different time bands. We will then build a software tool to use in case studies, to validate the use of time bands in structuring dependable systems.

Adaptation and diversity

This activity will help designers and assessors of socio-technical systems to address some of the hard problems caused by the difficulty of predicting how people adapt to computers. We will give designers greatly enhanced abilities to analyse quantitatively, control and exploit the phenomena of adaptation and diversity, which although often recognised in informal terms need more thorough and formal treatment. Our focus will be data-rich, knowledge intensive activities that are increasingly supported by automation.

Responsibility and trust

Inappropriate allocation or perception of responsibilities, and inappropriate levels of trust in the various system components, are important causes of failure in computer-based systems. This work will support the modelling, management and analysis of responsibility and trust during the design and deployment of such systems, by developing the necessary notations, techniques and software tools.

Confidence and Uncertainty in dependability cases

A "case" is the web of evidence and reasoning through which system dependability is assessed. DIRC defined "confidence-based" cases, which describe dependability claims together with the degree of confidence that can be had in them. We will produce methods for detailing and structuring cases, using the results of work on time bands; guidance for using more diverse evidence and arguments towards increasing confidence; new interdisciplinary understanding of the factors causing people to trust a case less (or more) than its contents warrant.

These activities are integrated into a coherent programme of work. An integration mechanism is the use of real-world case studies where we work with our partners in the project (Voca, British Energy, CAA and Qinetiq) to challenge and validate our research.