http://dspace.cityu.edu.hk:80/handle/2031/737 2013-04-30T08:38:35Z http://dspace.cityu.edu.hk:80/handle/2031/6518 Title: Enhanced term extraction based on probabilistic estimation from syntactic parse trees Authors: Zhang, Xing ( 張杏) Abstract: This research is an effort to explore how the syntactic information of term candidates can be exploited for the task of term extraction. It proposes an approach that represents a novel, linguistically motivated perspective in the area of terminological processing. The hypothesis of this work is that terms tend to perform certain types of syntactic functions more prominently than others. This syntactic behaviour of terms can be captured as termhood by estimating term probabilities from their occurrences in different syntactic paths. Based on a large corpus of parse trees, this feature allows for highly reliable statistics on properties of term occurrences. In essence, this method is a weighting scheme that measures probabilistic relations between term occurring patterns and syntactic paths, which is discussed in this thesis as Syntactic Function Value (SF-Value) and implemented in a term extraction system. Experiments conducted in this study begin by building up an automatic term extraction system that integrates such a weighting scheme. The purpose of these experiments is not to design a term extraction system with the best performance but to investigate the contributions of syntactic information to term extraction, including single-word terms, multi-word terms, and new terms. Specifically, these experiments are aimed at answering several research questions, including the following: whether linguistic knowledge as term rates in syntactic paths is useful for recognising candidate terms in medical texts; to what extent singleword terms can be extracted by this linguistic indicator; and subsequently how this linguistically based metric can be used to improve the ranking of multi-word terms, and whether term rates in syntactic paths can be used effectively for new term extraction. Finally, with the aim of investigating whether this linguistic metric can be used as an effective feature within a machine learning framework, a series of experiments are conducted on general term extraction and new term extraction using the method of Conditional Random Fields (CRF). Empirical results strongly argue that the term extraction approach proposed in this study demonstrates superior performance when compared with two existing term extractors. The key technique of this term extraction system, SF-Value, proves to be especially useful in selecting single-word terms and is also effective in enhancing the ranking of multi-word term candidates after their initial ranking by a statistical measure, C-Value. With regard to new term extraction, results show that SF-Value does not perform as well, which suggests that more features are needed to distinguish new terms from known terms. CRF framework is subsequently applied with the uses of SF-Value and term rate as added features for the extraction of new terms. Results show that this machine learning framework performs quite well in general term extraction. However, for the task of generating a list of new term candidates, this framework does not show good performance as expected. This result indicates that, for the task of new term extraction, more features related to new term candidates should be taken into consideration, in addition to syntactic function information. In conclusion, this study devises an innovative, linguistically motivated measure for term extraction and implements it in a software system. Comprehensive experiments are conducted to evaluate its performance, and empirical results demonstrate its superior performance in comparison with existing term extraction systems. Notes: CityU Call Number: P305.18.D38 Z46 2011; xii, 200 leaves 30 cm.; Thesis (Ph.D.)--City University of Hong Kong, 2011.; Includes bibliographical references (leaves 165-175) 2011-01-01T00:00:00Z http://dspace.cityu.edu.hk:80/handle/2031/6517 Title: The implicitness constructed and translated in diplomatic discourse : a perspective from grammatical metaphor Authors: Zhang, Junfeng ( 張峻峰) Abstract: The dissertation addresses the issue of implicitness and its translation in diplomatic discourse (DD). It takes the Chinese Ministry of Foreign Affairs web coverage, in both Chinese and English, of the 2001 Hainan Air-Collision Incident as the case corpus. The case study argues that Grammatical Metaphor (GM) can be supplemented by findings about Conceptual Metaphor in Cognitive Linguistics as a major implicitness-creating mechanism. Zhu’s (1996a) threefold analytical framework SOM (Structure of Meaning) is modified for a descriptive and explanatory study of translational treatment of the implicitness. As I will explain in Chapter Five, the "two very sorries" letter and its translated Chinese versions are included in the corpus for the significant role the construction and the translations of the letter have played. Implicitness can be a prominent feature of the DD produced in conflict-resolution scenarios. It is employed for covering up information not sharable to the public out of national interest concerns in DD and its translation. The implicitness can be regarded as being motivated by interpersonal considerations oriented to the desired responses of the public. Previous research has classified linguistic representations of implicitness mainly as lexical phenomena, i.e. ambiguity, vagueness, fuzziness, and generality. Lexis and grammar form the two ends of a dynamic lexicogrammatical continuum, where there is a mutual movement between them, responding to the actual needs of communication. These needs at times would cause the tension between discourse semantics and the lexicogrammar in a language. As a solution to the tension, GM emerges at the lexicogrammatical level and out of the need of discourse semantics. Implicitness can be a result of this semantic extension. Loss (or concealment) of information occurs when a "congruent" coding is packaged into a GM, in which the syntactic concealment of the human element is largely responsible for the implicitness at issue. The semantic duality and the condensation of information into more compact linguistic realization units in a GM are thus instrumental in creating implicitness. Two factors make the blending of some findings in Cognitive Linguistics into the GM theory necessary. Firstly, Cognitive Linguistics lends some working judging criteria of congruence to the GM theory. Secondly, both Conceptual Metaphor theory and GM theory look at metaphor from above, as a chosen linguistic form representing underlying possible multiple meanings. It is hypothesized that lexical choice comes before grammatical configuring in constructing the linguistic form of an intended message. It is argued that the blending can better explain the conceptual factors in word choices and transitivity selections in clause building and information presenting for creating implicitness. With reference to a collection of contextual data, the dissertation studies the deployment of GMs in the data and examines in particular how the translated versions play up certain elements "packaged" in the original while down-toning others in relation to the different diplomatic goals the Chinese government pursued. These comparisons are conducted against disclosed intentions of the discourse producers. It is found that: 1) Demarcation between ST and TT of the DD is blurred. 2) Lexical choices in each translation are consistent with and complemented by the use of GMs. 3) The syntactic concealment of the human element plays a key role in the making of Ideational GMs. 4) The Explicitation Hypothesis does not appear to be universal in translation. It is contended that the translation of the DD featured with implicitness is invested with a prominent interpersonal concern for maintaining international engagement, even at the expense of the ideational content. Such a concern is textually accountable in the framework of GM with each text in question viewed as an SOM. Notes: CityU Call Number: P306.2 .Z42 2011; xiii, 317 leaves 30 cm.; Thesis (Ph.D.)--City University of Hong Kong, 2011.; Includes bibliographical references (leaves 255-266) 2011-01-01T00:00:00Z http://dspace.cityu.edu.hk:80/handle/2031/6516 Title: English transitivity alternation in second language acquisition : an attentional approach Authors: Wang, Yuxia ( 汪玉霞) Abstract: This doctoral research investigates the acquisition of English transitivity alternation by adult Chinese EFL learners within an attentional framework. Specifically, the following research questions are addressed: i) whether instruction is effective and if yes, what instruction type is more effective in facilitating the acquisition of the target form, ii) whether the level of rule awareness as developed in different instruction types has differential effects on learning, and iii) whether aptitude correlates positively with the level of awareness and the extent of learning on the target form. These research questions are addressed in an experimental study for which 84 low- and 78 intermediate- proficiency learners were recruited. Participants at both proficiency levels were randomly assigned to a control, explicit-inductive or explicit-deductive group. Both the picture-stimulated production and grammaticality judgment tasks were conducted to assess the learning outcome in a format of pre-post-delayed tests. Learners' awareness of the target rule was categorized into three levels, namely the level of non-reporting, noticing and understanding, based on their responses to a post-exposure questionnaire. Meanwhile, learners' individual differences in aptitude were measured in two subtests on grammatical sensitivity and language analysis respectively. Analyses of the quantitative results revealed: i) form-focused instruction in both explicit groups proved to be more effective than the control group in acquiring English transitivity alternation; ii) the explicit-inductive and explicit-deductive instruction had differential learning effects for the intermediate learners, but not for the low-proficiency ones; iii) the results concerning the relationship between awareness and instruction type suggested that learners (both low and intermediate) engaged in more explicit learning conditions developed higher levels of awareness; iv) awareness at the level of noticing was sufficient to bring more learning for learners at both the low and intermediate proficiency levels; awareness at the level of understanding seemed to have more beneficial results only for learners at the intermediate level, but not for those at the low level; v) aptitude subtests on grammatical sensitivity and language analysis indicated that aptitude emphasized certain language learning abilities, i.e., aptitude was influenced by the learners' proficiency level but still differed from it; and vi) for both proficiency levels, significant correlations between learning gains in the receptive and productive tests and scores of aptitude subtests were only found for participants in the explicit-inductive groups, but not in the control or explicit-deductive groups. Pedagogical implications and suggestions for future research were also discussed. The findings suggest that the acquisition of English transitivity alternation follows as a consequence of the cognitive processing of language input, which is induced by the nature of task requirements in different learning conditions and influenced by individual differences in aptitude and learners' readiness as indicated in their prior language proficiency levels. Therefore, the effects on L2 acquisition of English transitivity alternation should be considered as a complicated interaction of a number of variables, including the nature of the target form, task requirements of learning activities, explicitness of L2 input, learners' individual differences in aptitude as well as their proficiency levels. In other words, the level of attention/awareness depends upon the nature of target linguistic form, the nature of instruction and learners' individual differences. Notes: CityU Call Number: PE1315.T72 W36 2010; xi, 305 leaves : ill. 30 cm.; Thesis (Ph.D.)--City University of Hong Kong, 2010.; Includes bibliographical references (leaves 252-270) 2010-01-01T00:00:00Z http://dspace.cityu.edu.hk:80/handle/2031/6514 Title: A phonetic study of Fuzhou Chinese Authors: Peng, Gongguan ( 彭攻關) Abstract:  Notes: CityU Call Number: PL1690.F8 P46 2011; xlvii, 528 leaves : ill. 30 cm.; Thesis (Ph.D.)--City University of Hong Kong, 2011.; Includes bibliographical references (leaves 367-373) 2011-01-01T00:00:00Z