tailieunhanh - Báo cáo khoa học: "Exploring Deterministic Constraints: From a Constrained English POS Tagger to an Efficient ILP Solution to Chinese Word Segmentation"

We show for both English POS tagging and Chinese word segmentation that with proper representation, large number of deterministic constraints can be learned from training examples, and these are useful in constraining probabilistic inference. For tagging, learned constraints are directly used to constrain Viterbi decoding. | Exploring Deterministic Constraints From a Constrained English POS Tagger to an Efficient ILP Solution to Chinese Word Segmentation Qiuye Zhao Mitch Marcus Dept. of Computer Information Science University of Pennsylvania qiuye mitch@ Abstract We show for both English POS tagging and Chinese word segmentation that with proper representation large number of deterministic constraints can be learned from training examples and these are useful in constraining probabilistic inference. For tagging learned constraints are directly used to constrain Viterbi decoding. For segmentation character-based tagging constraints can be learned with the same templates. However they are better applied to a word-based model thus an integer linear programming ILP formulation is proposed. For both problems the corresponding constrained solutions have advantages in both efficiency and accuracy. 1 introduction In recent work interesting results are reported for applications of integer linear programming ILP such as semantic role labeling SRL Roth and Yih 2005 dependency parsing Martins et al. 2009 and so on. In an ILP formulation non-local deterministic constraints on output structures can be naturally incorporated such as a verb cannot take two subject arguments for SRL and the projectivity constraint for dependency parsing. In contrast to probabilistic constraints that are estimated from training examples this type of constraint is usually hand-written reflecting one s linguistic knowledge. Dynamic programming techniques based on Markov assumptions such as Viterbi decoding cannot handle those non-local constraints as discussed above. However it is possible to constrain Viterbi 1054 decoding by local constraints . assign label t to word w for POS tagging. This type of constraint may come from human input solicited in interactive inference procedure Kristjansson et al. 2004 . In this work we explore deterministic constraints for two fundamental NLP problems English POS .

TỪ KHÓA LIÊN QUAN
crossorigin="anonymous">
Đã phát hiện trình chặn quảng cáo AdBlock
Trang web này phụ thuộc vào doanh thu từ số lần hiển thị quảng cáo để tồn tại. Vui lòng tắt trình chặn quảng cáo của bạn hoặc tạm dừng tính năng chặn quảng cáo cho trang web này.