Modular Formal Specification of Data and Behaviour

We propose a modular approach to the formal specification of the requirements on embedded systems. In this approach, requirements on data are specified as invariants on states. Requirements on behaviour are specified assertionally by temporal logic formulae, restricting the runs of the system. The proposed method is modular, because components can be specified and analysed in isolation, and the views of several components can be combined in an easy way. Requirements can be combined by simply putting them in conjunction. A mathematical framework supporting this approach is developed and implemented in the theorem prover PVS. The method is illustrated by formalising the requirements of a miniature embedded system. This specification is then analysed using the theorem prover, revealing some errors in the original specification

High performance work practices in small firms: a resource-poverty and strategic decision-making perspective

Contains fulltext : 116515.pdf (publisher's version ) (Open Access)High performance work practices (HPWPs) are human resource management practices aimed at stimulating employee and organisational performance. The application of HPWPs is not widespread in small organisations. We examine whether the implementation of coherent bundles of HPWPs (aimed at employee ability, employee motivation or at the opportunity to perform) depends on the scarcity of resources, as reflected in the size of the company, and on strategic decision-making in small firms related to the owner’s expertise and attitudes. In our research, a total of 211 employees from 45 small organisations were asked to rate the presence of HPWPs in their organisation. These averaged perceptions were linked to information provided by the owner–managers on the size of their firm and their own expertise and attitudes. The findings support that smaller but coherent bundles of HPWPs can be found in small organisations and that the implementation of these bundles depends on available resources, strategic decision-making and the combination of the two. These findings highlight the need to integrate the notions of resource poverty and strategic decision-making to understand the uptake of bundles of HPWPs within small firms

A compositional axiomatisation of safety and liveness properties for statecharts

Statecharts is a behavioral specification language proposed for specifying large real-time, event driven, reactive systems. It is a graphical language based on state-transition diagrams for finite state machines extended with many fea tures like hierarchy, concurrency, broadcast communication and time-out. By generating external events symbolically, Statecharts can be executed, thereby turning it into a programming language for real-time concurrency (as well as enabling rapid prototyping). As such it is amenable to compositional pro gram verification. We supply Statecharts with a compositional proof system for both safety and liveness properties which we prove to be sound and (rela tively) complete. Especially, we focus on extending compositional techniques for proving safety properties to liveness, without immediately adopting tem poral logic, since that formalism, elegant as it is, introduces some difficulties with a compositional treatment of sequentiality and looping