GridNexus: A Grid Services Scientific Workflow System

We introduce GridNexus, a graphical system for creating and executing scientific workflows in a grid environment. GridNexus allows the user to assemble complex processes involving data retrieval, analysis and visualization by building a directed acyclic graph in a visual environment. Workflows in GridNexus are described by a script written in a language called JXPL. The script can be executed either locally or in a remote managed-job environment. GridNexus enables the composition of larger software modules from smaller ones to build very complex tasks and separates the graphical user interface (GUI) from execution of the workflow. This increases system flexibility while retaining interactive capabilities. We compare our approach with that of similar projects, and provide an assessment of the system by highlighting two real-world scientific applications that have taken advantage of the GridNexus environment.