Database Research Group (CIS)

Document Type

Technical Report

Date of this Version



We study the problem of searching a repository of complex
hierarchical workflows whose component modules, both composite and
atomic, have been annotated with keywords. Since keyword search does
not use the graph structure of a workflow, we develop a model of
workflows using context-free bag grammars. We then give
efficient polynomial-time algorithms that, given a workflow and a
keyword query, determine whether some execution of the workflow
matches the query. Based on these algorithms we develop a
search and ranking solution that efficiently retrieves the
top-k grammars from a repository. Finally, we propose a novel
result presentation method for grammars matching a keyword query,
based on representative parse-trees. The effectiveness of our


scientific workflows, keyword search, result presentation



Date Posted:17 May 2013

This document has been peer reviewed.