  Scientific workflow is a powerful tool to streamline and organize
computational steps of scientific application. This paper presents Emerald, a
system that adds sophisticated cloud offloading capabilities to scientific
workflows. Emerald automatically offloads computation intensive steps of
scientific workflow to the cloud in order to enhance workflow performance.
Emerald provides easy-to-use APIs to help developers build cloud offloading
enabled scientific workflows. Evaluation showed that Emerald can effectively
reduce up to 55% of execution time for scientific applications.
