We use an encoding scheme similar to that of (Zhang et al., 2002 token before the period token after the period character to the right type of character to the right character to the left type of character to the left character to the right of blank after word type of character to the right of blank after word character left of first character of word type of character left of first character of word first character of the preceding word type of first character of the preceding word length of preceding word distance to previous period The features presented here may not be optimal.
unlike (Zhang et al., 2002), we do not use higher order features (for example, combinations of the above features).