Charles H.-P. Wen Li-C. Wang Jayanta Bhadra An incremental learning framework for estimating signal controllability in unit-level verification. 250-257 2007 conf/iccad/2007 ICCAD http://doi.acm.org/10.1145/1326073.1326126 db/conf/iccad/iccad2007.html#WenWB07