· Research Professor, School of Information Sciences, University of Illinois2025–
· Research Professor, Siebel School of Computing and Data Science2025–
· Chief Scientist, National Center for Supercomputing Applications (NCSA)2020–
· Director for Cyberinfrastructure Development and Adjunct Associate Professor, Louisiana State University (LSU)2006–2009
· Various roles including Principal Member of the Information Systems and Computer Science Staff, Supervisor of the Parallel Applications Technologies group, and Area Program Manager of High End Computing, JPL (Jet Propulsion Laboratory)1996–2006
· Computational Scientist, Cray Research, Inc.1993–1996