This thesis presents an approach to design, specify, validate, verify, implement, and evaluate composed web/grid services. Web and grid services can be composed to create new services with complex behaviours. The BPEL (Business Process Execution Language) standard was created to enable the orchestration of web services, but there have also been investigation of its use for grid services. BPEL s...

Bigraphical Reactive Systems (BRSs) have been proposed as a formal metamodel for global ubiquitous computing that encompasses process calculi for mobility, notably the π-calculus and the Mobile Ambients calculus, as well as graphical models for concurrency such as Petri Nets. In this paper we demonstrate that BRSs also allow natural formalizations of programming languages used in practice. We d...

This thesis presents an approach to design, specify, validate, verify, implement, and evaluate composed web/grid services. Web and grid services can be composed to create new services with complex behaviours. The BPEL (Business Process Execution Language) standard was created to enable the orchestration of web services, but there have also been investigation of its use for grid services. BPEL s...

Although Service-Oriented Architectures (SOAs) were not designed for multimedia processing, they speed up the development of distributed multimedia applications by allowing the composition or reconfiguration of existing services. For example, the Business Process Execution Language for Web Services (BPEL) is a powerful tool to orchestrate, model and execute workflows. However, due to its proces...

The Business Process Execution Language (BPEL) aims at enabling the usage of high abstraction levels when orchestrating Web Services to represent business processes. While this has partly been achieved, several tasks required for the creation of a BPEL process demand cumbersome implementation of technical details, adding little value for the actual business process. Real-world tool-support stil...

This paper investigates the use of the Business Process Execution Language for Web services (BPEL4WS/ BPEL) for managing scientific workflows. The complexity, unpredictability and inter-dependency of the components in a scientific workflow often demand great flexibility in a workflow-language in order to support; 1) exception handling, 2) recovery from uncertain situations, 3) user interactions...