Workflow Composition: Semantic Representations for Flexible Automation

Abstract

Many different kinds of users may need to compose scientific workflows for different purposes. This chapter focuses on the requirements and challenges of scientific workflow composition. They are motivated by our work with two particular application domains: physics-based seismic hazard analysis (Chapter 10) and data-intensive natural language processing [238]. Our research on workflow creation spans fully automated workflow generation (Chapter 23) using artificial intelligence planning techniques for assisted workflow composition [237,276] by combining semantic representations of workflow components with formal properties of correct workflows. Other projects have used similar techniques in different domains to support workflow composition through planning and automated reasoning [286,289,415] and semantic representations (Chapter 19). As workflow representations become more declarative and expressive, they enable significant improvements in automation and assistance for workflow composition and in general for managing and automating complex scientific processes. The chapter starts off motivating and describing important requirements to support the creation of workflows. Based on these requirements, we outline the approaches that we have found effective, including separating levels of abstraction in workflow descriptions, using semantic representations of workflows and their components, and supporting flexible automation through reuse and automatic completion of user specifications of partial workflows.