Learn More
A different way to execute pure LISP programs is presented. It delays the evaluation of parameters and list structures without ever having to perform more evaluation steps than the usual method. Although the central idea can be found in earlier work this paper is of interest since it treats a rather well-known language and works out an algorithm which(More)
The UK e-Science Programme is a £250M, 5 year initiative which has funded over 100 projects. These application-led projects are underpinned by an emerging set of core middleware services that allow the coordinated, collaborative use of distributed resources. This set of middleware services runs on top of the research network and beneath the applications we(More)
We review the various arguments which have been advanced for and against the use of executable speciications. Examples are given of the problems which may arise in applying this technique and of the beneets which may accrue. A case study is reported in which execution is used to validate the published speciication of a commercially available package. We(More)
The ability to compensate for previous activities, often in the case of failure or exceptional events, is an important feature of long-running business transactions. In this paper, we present several extensions to existing notions of compensation for business transactions. The extensions are described using a business process modeling language called StAC(More)
This paper describes RolEnact: a process-modelling notation used to provide enactable models of process instances. The paper shows how RolEnact models may be produced which are equivalent to role activity diagrams (RADs). This allows the modeller to describe processes in a notation (RADs); which can be understood both by process consultants and process(More)
When trying to understand the behaviour of large systems, such as the business processes of large enterprises, we often adopt diagramming techniques based on derivatives of data flow diagrams. For very complex systems such diagramming techniques suffer from the inability to abstract uniformly from arbitrary subcollections of components. In this paper we(More)
Formal methods are a nice idea, but the size and complexity of real systems means that they are impractical. We propose that a reasonable alternative to attempting to specify and verify the system in its entirety is to build and evaluate an abstract model(s) of aspects of the system that are perceived as important. Using a model will not provide proof of(More)
Designing systems of asynchronous web services is challenging. Addressing the design in terms of component reuse helps address important questions that need to be answered if dynamic configuration of business solutions from web services is to be achieved. The fact that the components are web services doesn't mean that all the problems of reuse have been(More)