- 2002-current: Director of Research and Development, Center for the Study of Biological Complexity, VCU Life Sciences Building, Richmond, VA 23284. Collateral appointment with Department of Gerontology, School of Allied Health Professions (2004-current). Associate Professor, Department of Emergency Medicine, School of Medicine. Adjunct Associate Professor, VCU School of Social Work.
- 2000-2002: Research Assistant, Department of Biostatistics, Medical College of Virginia, Richmond, VA 23284, Visiting Faculty, Department of Sociology and Anthropology, Virginia Commonwealth University, Richmond, VA 23284
- 1999-2000 : Associate Professor, Department of Mathematics, Trinity University, San Antonio, TX 78212-7200; Adjunct Associate Professor, Department of Family Medicine, University of Michigan School of Medicine, Ann Arbor, MI 48109
- 1998-1999 : Associate Professor, Department of Community Dentistry, University of Texas Health Science Center San Antonio, San Antonio, TX 78284; Adjunct Associate Professor, Department of Family Medicine, University of Michigan School of Medicine, Ann Arbor 48109.
- 1996--1998 : Adjunct Associate Professor, Department of Mathematics, University of Michigan, East Hall, Ann Arbor, MI 48109.
- 1995--1998 : Research Scientist, Reproductive Sciences Program, University of Michigan at Ann Arbor, 300 North Ingalls Blvd., Ann Arbor, 48109; Chief Information Officer, Comprehensive Gender Services Program, University of Michigan Medical Center, 1500 East Medical Center Drive, Ann Arbor, MI 48109-0050.
- 1994--1998 : Visiting Senior Research Scientist, Institute of Gerontology, Group on Computational Medicine, Public Health, and Biotechnology, University of Michigan at Ann Arbor, 300 North Ingalls, Ann Arbor, MI 48109-2007.
- 1989--1994 : Associate Director, University of Texas System Center For High Performance Computing, 1.154 CMS, BRC, 10100 Burnet Road, Austin, TX 78758-4497; Adjunct Associate Professor of Biomedical Engineering, University of Texas at Austin, Austin, TX; Adjunct Associate Professor of Physiology, University of Texas Health Science Center, 7703 Floyd Curl Drive, San Antonio, TX.
- 1988--1989 : Computational Research Scientist, ETA Systems, Inc., 1450 Energy Park Drive, St. Paul, MN; Adjunct Associate Professor of Ophthalmology, University of Louisville, School of Medicine, Louisville, KY; Visitor-in-Residence, Institute For Mathematics And Its Applications, University of Minnesota, Minneapolis, MN; Adjunct Associate Professor of Physiology, University of Texas Health Science Center, 7703 Floyd Curl Drive, San Antonio, TX.
- 1985--1988 : Associate Professor of Engineering Mathematics and Computer Science, University of Louisville; Associate Professor, Department of Community Medicine, University of Louisville, School of Medicine, Adjunct Associate Professor of Ophthalmology, University of Louisville, School of Medicine, Louisville, KY; Adjunct Associate Professor of Physiology, University of Texas Health Science Center, 7703 Floyd Curl Drive, San Antonio, TX.
- 1982--1985 : Assistant Professor, Department of Mathematics, Illinois Institute of Technology, Chicago, IL 60616; Part--time Instructor in Computer Science, Roosevelt University, Chicago, IL; Part--time Instructor in Mathematics, Harper Community College, Palatine, IL.
- 1981--1982 : Visiting Lecturer, Department of Mathematics, University of California, Santa Barbara, CA; Lecturer, Department of Computer Science and Mathematics, Santa Barbara City College, Santa Barbara, CA.
- 1979--1981 : Assistant Professor, Department of General Systems, University of Southern California, Los Angeles, CA; Research Assistant Professor, Department of Communication, Arts, and Sciences, University of Southern California, Los Angeles, CA.
- 1978--1979 : Senior Research Analysis, Planning Research Corporation. Secret Clearance. Work in systems design and analysis; Postdoctoral fellow, Department of Biomedical Engineering, University of Southern California (Advisor: F.S. Grodins); NSF Summer Student Training Program Advisor; Onsite medical technician, Healthgarde Inc. and Senior Programmer, Department of Respiratory Physiology (Advisor: John Mohler)
- 1977--1978 : Staff consultant, Department of Biometry, Medical University of South Carolina, Charleston, SC (Advisors: R. Duncan and M.C. Miller III); Part--time Instructor, Department of Mathematics, University of South Carolina at Charleston, Charleston, SC.