Zhendong Zhao Lei Yuan Yuxuan Wang Forrest Sheng Bao Shunyi Zhang Yanfei Sun A Novel Model of Working Set Selection for SMO Decomposition Methods http://arxiv.org/abs/0706.0585 2007 CoRR abs/0706.0585 db/journals/corr/corr0706.html#abs-0706-0585 informal publication