************************************************************************* Department of Mathematical Sciences The Johns Hopkins University SEMINAR ************************************************************************* Professor Cheng Cheng April 27, 2000 Department of Mathematical Sciences 304 Whitehead Hall The Johns Hopkins University Preseminar: 3:00 p.m. Refreshments: 3:30 p.m. Seminar: 4:00 p.m. ************************************************************************* TEST OF COMPLETE RANDOMNESS AND EXTRACTION OF CLUSTERS ON A HOMOGENEOUS SPACE ************************************************************************* ABSTRACT Roughly speaking, as far as proability distributions are concerned, a "homgeneous space" is a topological space on which the uniform distribution can be properly defined. Intervals, squares, cubes, and spheres are examples of homogeneous spaces. This talk will present a simulation-based statistical test of complete randomness defined in terms of certain point processes on a homogeneous space. A Monte Carlo power study of testing complete randomness on the unit sphere and open questions will be discussed. Upon rejecting the complete randomness null hypothesis, it is natural to further investigate which observed points resulted in the rejection. This leads to the cluster extraction problem. An algorithm for extracting clusters from the observed points (data), along with an index measuring the "tightness" of the clusters, will be presented. *************************************************************************