2002 Journal of Software, )

Transcription

1 /2002/13(04) Journal of Software Vol13 No4 ( ); ( ) hdstsysgn@cisezjueducn http//wwwzjueducn ; ; ; TP18 A ( ) (anaphora) 3 [1~3] GroszSidnerWalker Grosz Sidner PAL WalkerMA Grosz Sidner Focus Stack Cache ( ) ; ( ) (1974 ) ; (1959 )

2 733 [4] 1 A A { f = v f = v } T A = f n = v n n > 0 ; n Z f i v i f =v i f i v i A / A A T A' { A1 A 2 A n = } n > 0 ; n Z A i i=1 n (multiple-branched and multiple-labeled tree model MMT ) [5] MMT MMT MMT 9 [5] 2 21 LiYan-hui [6] (individuate) ( ) V L V n <W 1 W 2 W n > n W i V M L fw + n M W + n W i (i 1 n) W i M k k n W + n W j ={ } W j W i ={ }; a ={ }; a ={ }; ; ; ( 1 ) M 22

3 734 Journal of Software (4) [6] Ge Ju Zhong Duan Pian Ben Bu Sentence Speech Words Text Morpheme Word Paragraph Book Xie Fig1 Compositive habit between Chinese quantifier and meta_anaphoric symbol 23 EE 1 EE [7] EE Elementary Event EE EE EE EE EE EE EE tell_event( ) preposition_event( ) quote_event( ) EE EE EE EE EE EE 1 EE Condition Cause Conjunction( ) Content( ) Explanation( ) Disjunction( ) Reference( ) 3 EE EE EE 1 EE ; EE EE Content( ) Explanation( ) Disjunction( ) Reference( ) EE EE EE 3 (1) (2) 1 {( )+( )+( )+( )+

4 } 2 EE ( ) 3 EE 1 2 EE EE EE EE_CurrentFocus EE ; ( ); EE_CurrentFocus EE_OldFocusStack ( ) ; ( ) 4 EE 1~3 EE_CurrentFocus EE_OldFocusStack ( ) Word Word { 1 2} EE11 tell_event EE CurrentFocus( EE ) tell_event Theme( EE ) ThemeStack( Theme ) FocusStack( ) EE_CurrentFocus( ) 1 1 EE11 tell_event Content tell_event EE_OldFocusStack CurrentFocus tell_event;theme ;ThemeStack=NULL;FocusStack=NULL; EE_CurrentFocus=tell_event;EE_OldFocusStack= 1 EE111Word EE [7] Word EE111 tell_event 1 EE (condition) CurrentFocus=Word;Theme Word;ThemeStack= ;FocusStack=tell_event; EE_CurrentFocus=tell_event;EE_OldFocusStack= 1 EE112 EE it it EE CurrentFocus it EE112 EE CurrentFocus= ;Theme Word(it);ThemeStack=Word ;FocusStack=Word tell_event; EE_CurrentFocus=EE112;EE_OldFocusStack=tell_event 1 EE21 EE 2

5 736 Journal of Software (4) 3EE112 EE21 2 Conjunction 2 EE EE (condition) CurrentFocus= ;Theme ;ThemeStack=Word ;FocusStack= Word tell_event; EE_CurrentFocus=EE112;EE_OldFocusStack=tell_event 1 EE21 EE112 EE22Word EE 3 EE Sentence1 Sentence2 Condition Condition Cause Someone Condition Word EE11 Content EE111 Condition tell_event it Paragraph The speech Word Disjunction E EE21 Conjunction Mapping words EE22 It Expert 1 2 Fig2 The multiple-branched and multiple-labeled tree of example MMT Word CurrentFocus=Word;Theme Word; ThemeStack= Word ;FocusSta- ck= Word tell_event; EE22 EE21 Cause( )EE22 EE_CurrentFocus=EE22;EE_OldF ocusstack=ee112 tell_event EE11 MMT ( 2 ) ~ ~ (1) (2) (3) 3 General controlling module Input module Meta-Anaphora search module Meta-Anaphoric resolution module Statistic module Fig3 A raw drawing of the system 3 VisualC MMT MMT

6 737 MMT Table 1 Recognizability of Zi type of meta-anaphora 1 Meta-Anaphora (48 items) Non-Meta-Anaphora (70 items) Uncertainty (5 items) Items found by the algorithm Items match the criterian Recall factor (%) Pertinency factor (%) (48 ) (70 ) (5 ) ( ) 925% 89% % 71% % % % (+ ) (1) (2)

7 738 Journal of Software (4) 5 References [1] Grosz BJ Sidner CL Attentions intentions and the structure of discourse Computational Linguistics (3)175~204 [2] Grosz BJ Joshi AK Weinstein Scott Centering a framework for modeling the local coherence of discourse Computational Linguistics (2)203~225 [3] Huls C Claassen W Bos E Automatic referent resolution of deitic and anaphoric expressions Computational Linguistics (1)59~80 [4] Chen Zhi-qun FB-Model of Chinese discourse semantic representation Journal of Hangzhou University (Natural Science Edition) (Suppl)29~33 (in Chinese) [5] Feng Zhi-wei Natural Language Processing Shanghai Shanghai Foreign Language Teaching and Education Press 1996 (in Chinese) [6] Lu Bing-fu Analysing syntactic relation using semantics and pragmatics Journal of Chinese Philology ~367 (in Chinese) [7] Azzam S Humphreys K Gaizauskas R Evaluating a focus-based approach to anaphora resolution In Proceedings of the 36th Annual Meeting of the Association for Computational Linguistics and 17th International Conference on Computational Linguistics Montreal Morgan Kaufmann Publishers Inc ~78 [4] FB ( )199825( )29~33 [5] 1996 [6] ~367 Study on Meta-Anaphoric Resolution in Chinese Discourse Understanding ZHANG Wei ZHOU Chang-le (Department of Computer Science and Engineering College of Information Science and Technology Zhejiang University Hangzhou China); (Institute of Artificial Intelligence Zhejiang University Hangzhou China) hdstsysgn@cisezjueducn http//wwwzjueducn Abstract Anaphoric resolution is a hot field in computational linguistics According to the research it is found that a kind of anaphora meta-anaphora which represents the form of sentence paragraph or discourse (not the subject or object of the sentence) plays an important role in discourse So meta-anaphoric resolution affects the computer s ability of discourse understanding This paper focuses on the meta-anaphoric resolution A new concept called Elementary Event focus (EE_focus) is introduced And some meta-anaphoric resolution algorithms based on the concept are designed The algorithms examined by a large Chinese natural language corpus The experimental results show that the EE_focus set can do good job in meta-anaphoric resolution The work enriches the theory of discourse s structural representation It is important in confirming the cohesion and coherence of the Chinese discourses Key words natural language understanding; Chinese text analysis; anaphoric resolution; meta-anaphora; EE_focus Received September ; accepted November Supported by the National Natural Science Foundation of China under Grant No