We focus on mixtures of factor analyzers from the perspective of a method for model-based density estimation from high-dimensional data, and hence for the clustering of such data. This approach enables a normal mixture model to be fitted to a sample of n data points of dimension p, where p is...

This dissertation investigates the problem of developing models and mechanisms for user authorization based on uncertain evidence and dynamic trust. The research directions are modeling dynamic trust, modeling uncertain evidence, and integrating them with role assignment for user authorization....