The chunking states included in the NE classes were: BEGIN (beginning of a NE), MIDDLE (middle of a NE), END (ending of a NE), and SINGLE (a single-word NE).
in text-based NER, better results are obtained using discriminative schemes such as maximum entropy (ME) models (Borthwick, 1999;Chieu and Ng, 2003), support vector machines (SVMs) (Isozaki and Kazawa, 2002), and conditional random fields (CRFs) (McCallum and Li, 2003).