A NEW SHOOTING METHOD FOR QUASI-BOUNDARY REGULARIZATION OF MULTI-DIMENSIONAL BACKWARD HEAT CONDUCTION PROBLEMS

We employ a quasi-boundary regularization to construct a two-point boundary value problem for multi-dimensional backward heat conduction equations. The multidimensional backward heat conduction problem (BHCP) is renowned as severely illposed because the solution does not fullly depend on the data. In order to numerically tackle the multi-dimensional BHCP, we propose a Lie-group shooting method (LGSM) in the time direction to find the unknown initial conditions. The pivot point is based on the establishment of a one-step Lie group element G(T) and the construction of a generalized mid-point Lie group element G(r). Then, by imposing G(T) = G(r) we can search for the missing initial conditions through a minimum discrepancy to the real targets by the numerical ones, in terms of the weighting factor r is an element of ( 0, 1). When numerical examples are tested, we find that the LGSM is applicable to the BHCP. Even with noisy final data, the LGSM is also robust against disturbance.