To divide and conquer search ranking by learning query difficulty.

@inproceedings{zhu-2009-divide, author = {Zeyuan Allen Zhu and Weizhu Chen and Tao Wan and Chenguang Zhu and Gang Wang and Zheng Chen}, editor = {David Wai-Lok Cheung and Il-Yeol Song and Wesley W. Chu and Xiaohua Hu and Jimmy Lin}, title = {{To divide and conquer search ranking by learning query difficulty}}, booktitle = {{Proceedings of the 18th ACM Conference on Information and Knowledge Management, CIKM 2009, Hong Kong, China, November 2-6, 2009}}, pages = {1883--1886}, publisher = {ACM}, year = {2009}, url = {https://doi.org/10.1145/1645953.1646255}, doi = {https://doi.org/10.1145/1645953.1646255} }