Implicit Role Linking on Chinese Discourse: Exploiting Explicit Roles and Frame-to-Frame Relations

Proceedings of the 53rd Annual Meeting of the Association for Computational Linguistics and the 7th International Joint Conference on Natural Language Processing, pages 1263–1271, Beijing, China, July 26-31, 2015. c⃝2015 Association for Computational Linguistics Implicit Role Linking on Chinese Discourse: Exploiting Explicit Roles and Frame-to-Frame Relations Ru Li1,2, Juan Wu1, Zhiqiang Wang1 and Qinghua Chai3 1School of Computer and Information Technology 2Key Laboratory of Ministry of Education for Computation Intelligence and Chinese Information Processing 3School of Foreign Languages, Shanxi University, Taiyuan, China {liru,charles}@sxu.edu.cn, {wujuan_0922,zhiq.wang}@163.com Abstract There is a growing interest in research- ing null instantiations, which are those implicit semantic arguments. Many of these implicit arguments can be linked to referents in context, and their discoveries are of great benefits to semantic process- ing. We address the issue of automat- ically identifying and resolving implicit arguments in Chinese discourse. For their resolutions, we present an approach that combines the information about overtly la- beled arguments and frame-to-frame rela- tions defined by FrameNet. Experimental results on our created corpus demonstrate the effectiveness of our approach. 1 Introduction In natural discourse, only a small proportion of the theoretically possible semantic arguments of predicates tend to be locally instantiated. Other locally unrealized semantic roles are called null instantiations (NIs). Nevertheless, many of these implicit roles, while linguistically unexpressed, can often be bound to antecedent referents in the discourse context. What’s more, capturing such implicit semantic roles and linking them to their antecedents can dramatically help text understanding. Example (1) shows an analyzed result (Li, 2012) by employing Chinese FrameNet (Liu, 2011), which is a lexical semantic knowledge base based on the frame semantics of Fillmore (1982) and takes Berkeley’s FrameNet Project (Baker et al., 1998) as the reference. In Chinese FrameNet, the predicates, called lexical units (LU), evoke frames which roughly correspond to different events or scenarios. Each frame defines a set of arguments called Frame Elements (FE). The set of FEs is further split into core FEs and non-core FEs. Particularly, the core FEs are the essential components of a frame and can be defined by themselves. However, not all core FEs of a frame can be realized simultaneously in a sentence. These non-instantiated FEs are considered as null instantiations of the frame elements. Depending on the interpretation type of the omission, Chinese FrameNet divides the NIs into two categories: 1) Indefinite Null Instantiations (INIs), the missing element which can be understood given interpre- tational conventions and do not need resolution, and 2) Definite Null Instantiations (DNIs), the missing element which is something that can be understood in the linguistic or discourse context, and the fillers need to be inferred from the context through resolutions. (1) [U:¥(]Entity•´ ´ ´ á á áu u u, , ,a a a [<E¥(]Category, Ú ��¥(!Ï&¥(!í–¥(�Óá˜a" [The celestial burial satellite]Entity is Being_in_category [artificial satellite]Category , and belongs to the same category with reconnaissance, communications and meteorological satellite. ØÓ�´^åˆÉ§´;€^5•˜�•Ý�¶pÝ ½ØÓ§˜„u u u� � � ¦ ¦ ¦ £ £ £ [�å/¥L¡3000õúp? �‚¥;�þ]Goal"[Theme DNI] [Agent INI] The purpose is …

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