Such approaches have been tried recently in restricted cases ( McCallum et al. , 2000 ; Eisner , 2001b ; Lafferty et al. , 2001 ) .
maximum entropy markov models for information extraction and segmentation
A McCallum D Freitag F Pereira
The resulting machine must be normalized , either per-state or globally , to obtain a joint or a conditional distribution as desired . Such approaches have been tried recently in restricted cases ( McCallum et al. , 2000 ; Eisner , 2001b ; Lafferty et al. , 2001 ) . Normalization may be postponed and applied instead to the result of combining the FST with other FSTs by composition , union , concatenation , etc. .
Such approaches have been tried recently in restricted cases ( @@CITATION ; Eisner , 2001b ; Lafferty et al. , 2001 ) .