A novel approach to user-steering in scientific workflows

Scientific workflows (swf) are commonly used to model and execute large-scale scientific experiments. From the scientist's perspective the workflow execution is like black boxes. The scientist submits the workflow and at the end, the result or a notification about failed completion is returned. Concerning long running experiments or when workflows are in experimental phase it may not be acceptable. Thus scientists need to monitor the experiment during its execution in order to fine-tune their experiments or to analyze partial results and dynamically interfere with the execution of the simulation. To support the scientist with special user interaction tool we introduced the concept of intervention points (iPoints) where the user takes over the control for a while and has the possibility to interfere, namely to change some parameters or data, or to stop, to restart the workflow or even to deviate from the original workflow model during enactment. We plan to implement our solution in IWIR language which was targeted to provide interoperability between four existing well-known SWfMS within the framework of the SHIWA project.