An Acquisition Model for both Choosing and Resolving Anaphora in Conjoined Mandarin Chinese Sentences

An Acquisition Model for both Choosing and Resolving Anaphora in Conjoined Mandarin Chinese Sentences Benjamin L. Chen Application Software Department Computer and Communication Research Laboratories Industrial Technology Research Institute W300/CCL, #1 RA~D Rd. I, Hsinchu, 30045, Taiwan, R. O. C. e-mail: blchen@jaguar .ccl.it ri.org.tw Von-Wun Soo Department of Computer Science National Tsing-Hua University Hsinchu, 30043, Taiwan, R. O. C. e-mail: eoo@es.nthu.edu.tw Abstract Anaphoric reference is an important linguistic phe- nomenon to understand the discourse structure and content. In Chinese natural language processing, there are both the problems of choosing and resolv- ing anaphora. In Mandarin Chinese, several linguists have attempted to propose criteria to ezplain the phe- nomenon of anaphora but with controversial results. On the other hand, search-based computational tech- niques for resolving anaphora are neither the best way to resolve Chinese anaphora nor to facilitate choosing anaphora. Thus, to facilitate both choosing and resolv- ing anaphora with accuracy and efficiency, we propose a case-based learning model G-UNIMEM to automat- ically acquire anaphorie regularity from a sample set of training sentences i, which are annotated with a list of features. The regularity acquired from training was then tested and compared with other approaches in both choosing and resolving anaphora. Keywords: anaphoric reference, semantic roles(case), natural language acquisition, ease- based learning. i Introduction In discourse, there may be anaphora in two consec- utive sentences. When anaphora appear in a pair of consecutive sentences, the two consecutive sentences are called conjoined sentences. In real life conver- sation, we frequently choose and resolve anaphora to understand the utterances. There are primarily three types of anaphora in Mandarin Chinese: zero (ellipsis), pronominal (using pronoun) and nominal anaphora[4]. Let's take the conjoined Chinese sen- tencez in (B) to illustrate the phenomenon. The con- 1This paper is partially supported" by the Minis- ter of Economic Affairs, R.O.C. under the project no. 33H3100 at ITRI and by National Science Councial of R.O.C. under the grant no. NSC81-0408-E007-02 at National Tsing Hua University. The authors also want to thank Dr. Martha Pollack for valuable comments during 1991 UCSC linguistic institute. joined sentence in (C) is the English translation of the Chinese sentences m (B). (B) Yueh-haa sheng-bing. [ ] i-thing hui-chia-le. John got sick [ ] already gone home (C) Because John .as sick, he has gone home. Because the anaphora in (B) is a zero anaphora and there is no zero anaphora in English, the antecedent of zero anaphora in (B) must be resolved first before choosing an appropriate pronominal anaphora in Chi- nese to English translation. In the translation from (C) to (B), it is not good to directly translate an En- glish pronoun to a Chinese pronoun. A better way is to resolve the anaphora ire (C) and then choose an appropriate type of anaphora in Chinese. In natural language processing, better results seems to be attainable if rich linguistic or domain knowl- edge is available. However it generally costs much and doesn't seem to be realistic. The same situa- tion applies for resolving …

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