|The Structure of
a system can contribute to its dependability, understandability
and its ability to evolve. In this Research Theme, DIRC participants
have studied the structure of both human organisations and technical
systems (and the way they interact). The Structure page
also provides information about the new book on this work.
of computer-based systems is that they are required to function
at many different time scales (from microseconds or less to hours
or more). Time is clearly a crucial notion in the specification
(or behavioural description) of computer-based systems, but it
has a wide range of technical, social and psychological properties.
The Timeliness theme explores
this rich set of issues.
An essential element of dependability is protective redundancy, or
fault tolerance. But the risk of common failures among redundant
elements needs to be contained by pursuing diversity. The Diversity
theme studies the advantages and difficulties of pursuing diversity
both in systems and processes, including the socio-techncial processes
that develop technical and socio-technical systems. The work includes
empirical studies as well as probabilistic modelling.
In the Responsibility theme,
we explore one of the major differences between people and computers:
people can be given or assume responsibilities and computers
can't. Many system failures are, at least, partly a consequence of
responsibility failures. To reduce responsibility-related failures,
we need to develop a deeper understanding of these failures, to
understand how responsibilities interact in complex computer-based
systems and to invent ways of making responsibilities explicit in
models that can be used to inform system design.
|Risk in computer-based
systems is more heterogeneous and difficult to capture than conventional
systems because they are deeply embedded in social and organizational
contexts. The Risk theme emphasizes the need to consider issues
of Risk perception since different participants in an organization
have very different perception of the existence and severity of
Risks. We also consider mechanisms for handling Risk arising for
the ongoing process of change in organizational systems.