WP1: Timing and Structure

This workpackage is concerned with the role time plays within any structural description of complex computer-based systems, for example, socio-technical systems. We aim to explore the benefits of placing time at the centre of any description of system structures. To exploit the unique properties of time, with the aim of producing more dependable computer-based systems it is desirable to explicitly identify distinct time bands in which the system is situated. Such a framework enables the temporal properties and associated dynamic behaviour of existing systems to be described and the requirement for new or modified systems to be specified.

We are currently working on developing a sound semantics for a system model based on a finite set of distinct time bands. Some unique requirements must be satisfied in such a framework. For example, in the context of any particular band, activities within faster bands are instantaneous, whereas they are static within slower bands; between bands an event (an activity without duration) at one band can be mapped to an activity at a lower band. The time band model is also considered to deal with continuous time and discrete time, continuous states and discrete states. Machine assisted tools are to be developed so as to apply the framework in practice.

This research primarily involves Alan Burns, Jim Woodcock and Kun Wei at York.