“…Given an input sequence x = (w 1 , ..., w n ) where w i is the i-th eojeol, Korean morphological analysis aims to produce an output sequence y = ( m 1 , t 1 , ..., m k , t k ) where m j is the j-th morpheme and t j is its POS tag. Korean morphological analysis is different from existing NLP tasks such as English POS tagging (Toutanova et al, 2003;Manning, 2011), and joint word segmentation and POS tagging for Chinese (Zhang and Clark, 2008;Shao et al, 2017;Chen et al, 2017). In English POS tagging, a word and its tag have a one-to-one mapping so that the length of an input sequence is equal to that of an output sequence.…”