1. A method comprising: building a hierarchical multi-stage model of asset failure risk for complex heterogeneously distributed physical assets, said hierarchical multi-stage model considering heterogeneity of failure patterns for said assets; analyzing at least one data stream to determine a change in said failure patterns; and dynamically updating said hierarchical multi-stage model to obtain an updated hierarchical multi-stage model based at least in part on said change in said failure patterns; wherein said considering heterogeneity of failure patterns for said assets comprises: performing multi-dimensional segmentation on data comprising failure history for said assets to obtain segmented data; and implementing hierarchical modeling to integrate heterogeneous clusters of failure risks for said assets from said segmented data.