Electronic Journal of Differential Equations, Conference 03 (1999), pp. 119-125. Title: Determination of the source/sink term in a heat equation Authors: Ping Wang (Schuylkill Haven, PA, USA) Kewang Zheng (Hebei Univ. of Science and Technology, China) Abstract: In this work, we consider the problem of determining an unknown parameter in a heat equation with ill-posed nature. Applying Tikhonov regularization, we obtain a stable approximation to the unknown parameter from over-specified data. We also present numerical computations that verify the accuracy of our approximation. Published July 10, 2000. Math Subject Classifications: 35K05, 35R25. Key Words: Heat equation; inverse problem; regularization.