Lecture, Department of Computer and Mathematical Sciences, University of Houston-Downtown, Houston, Texas, 2010 through present.
Professor of Computer and Applied Mathematical Sciences, University of Houston-Downtown, Houston, Texas, 1987 through Lecturer.
Professor and Chairman of Computer and Information Science, Indiana University, Purdue University at Indianapolis, IN, 1987.
Professor and Acting Chairman of Computer and Information Science, Indiana University, Purdue University at Indianapolis, IN, 1986 through 1987.
Professor of Computer and Information Science, Indiana University, Purdue University at Indianapolis, IN, 1983 through 1986.
Professor of Mathematics and Computer Science, Indiana State University, Terre Haute, IN, 1982 through 1983.
Professor of Mathematics and Computer Science Visiting, Indiana University, Purdue University at Indianapolis, 1981 through 1982.
Professor of Mathematics and Computer Science, Indiana State University, Terre Haute, IN, 1975 through 1981.
Associate Professor of Mathematics, Indiana State University, Terre Haute, IN, 1971 through 1975.
Assistant Professor of Mathematics, Indiana State University, Terre Haute, IN, 1969 through 1971.
Assistant Professor of mathematics Visiting, Carnegie Mellon University, 1968 through 1969.
Assistant Professor of Mathematics, Carnegie Mellon University, Pittsburgh, PA, 1967 through 1968.
Consultant Mathematician, I.B.M. Corporation, Los Angeles Scientific Center, CA, 1964 through 1967.
Mathematician and Programmer, I.B.M. Corporation, San Jose, 1963 through 1964.
Teaching Assistant of Algebra and Calculus, University of California, Los Angeles, September 1961 through 1963.