All the proposed approaches are evaluated on multimedia retrieval tasks with large-scale video collections. Beyond multimedia collections, we also evaluate our approaches on meta-search tasks with large-scale text collections. Experi mental evaluations demonstrate the promising performance of the probabilistic retrieval framework with query analysis and context analysis in the task of knowledge source combination. The applicability of the proposed methods can be extended to many other areas, such as question answering, web IR, cross-lingual IR, multi-sensor fusion, human tracking, and so forth.
