This research is on the numerical study of strongly gravitating systems with special emphasis on the properties of the gravitational waves they generated in dynamical evolutions. This uses supercomputers for fully numerical treatments, and semi-analytical methods closely coupled to the numerical treatments, to study highly non-linear and dynamical astrophysical events, like the inspiral coalescence of compact binary systems consisting of neutron stars and/or black holes. One of the focuses of the research is on the accurate numerical constructions and analyses of 3D black hole spacetimes. Instead of the traditional approach of using time slicings to avoid the singularities inherent in black hole spacetimes, Prof. Suen's group will develop an approach in full 3+1 numerical relativity which uses the apparent horizons as inner boundaries in dynamical evolutions. This apparent horizon boundary condition approach is expected to have major impact on the numerical study of black hole spacetimes. Apparent horizons and event horizons are important characteristic of black holes. The PI is developing routines to determine their existence and locations, as well as tools for analyzing their properties, in a numerically constructed 3+1 dimensional spacetime. These routines, to be available to the numerical relativity community soon, will have impact on the study of black holes.