Focusing for Pronoun Resolution in English Discourse: An Implementation

Anaphora resolution is one of the most active research areas in natural language processing. This study examines focusing as a tool for the resolution of pronouns which are a kind of anaphora. Focusing is a discourse phenomenon like anaphora. Candy Sidner formalized focusing in her 1979 MIT PhD thesis and devised several algorithms to resolve definite anaphora including pronouns. She presented her theory in a computational framework but did not generally implement the algorithms. Her algorithms related to focusing and pronoun resolution are implemented in this thesis. This implementation provides a better comprehension of the theory both from a conceptual and a computational point of view. The resulting program is tested on different discourse segments, and evaluation and analysis of the experiments are presented together with the statistical results.Comment: iii + 49 pages, compressed, uuencoded Postscript file; revised version of the first author's Bilkent M.S. thesis, written under the supervision of the second author; notify Akman via e-mail ([email protected]) or fax (+90-312-266-4126) if you are unable to obtain hardcopy, he'll work out somethin

Anaphora and Discourse Structure

We argue in this paper that many common adverbial phrases generally taken to signal a discourse relation between syntactically connected units within discourse structure, instead work anaphorically to contribute relational meaning, with only indirect dependence on discourse structure. This allows a simpler discourse structure to provide scaffolding for compositional semantics, and reveals multiple ways in which the relational meaning conveyed by adverbial connectives can interact with that associated with discourse structure. We conclude by sketching out a lexicalised grammar for discourse that facilitates discourse interpretation as a product of compositional rules, anaphor resolution and inference.Comment: 45 pages, 17 figures. Revised resubmission to Computational Linguistic

An Incremental Model of Anaphora and Reference Resolution Based on Resource Situations

Notwithstanding conclusive psychological and corpus evidence that at least some aspects of anaphoric and referential interpretation take place incrementally, and the existence of some computational models of incremental reference resolution, many aspects of the linguistics of incremental reference interpretation still have to be better understood. We propose a model of incremental reference interpretation based on Loebner’s theory of definiteness and on the theory of anaphoric accessibility via resource situations developed in Situation Semantics, and show how this model can account for a variety of psychological results about incremental reference interpretation

Anaphora resolution for Arabic machine translation :a case study of nafs

PhD ThesisIn the age of the internet, email, and social media there is an increasing need for processing online information, for example, to support education and business. This has led to the rapid development of natural language processing technologies such as computational linguistics, information retrieval, and data mining. As a branch of computational linguistics, anaphora resolution has attracted much interest. This is reflected in the large number of papers on the topic published in journals such as Computational Linguistics. Mitkov (2002) and Ji et al. (2005) have argued that the overall quality of anaphora resolution systems remains low, despite practical advances in the area, and that major challenges include dealing with real-world knowledge and accurate parsing. This thesis investigates the following research question: can an algorithm be found for the resolution of the anaphor nafs in Arabic text which is accurate to at least 90%, scales linearly with text size, and requires a minimum of knowledge resources? A resolution algorithm intended to satisfy these criteria is proposed. Testing on a corpus of contemporary Arabic shows that it does indeed satisfy the criteria.Egyptian Government

Generating referring expressions in a domain of objects and processes

This thesis presents a collection of algorithms and data structures for the generation of pronouns, anaphoric definite noun phrases, and one-anaphoric phrases. After a close analysis of the particular kinds of referring expressions that appear in a particular domain -that of cookery recipes -the thesis presents an appropriate ontology and a corresponding representation language. This ontology is then integrated into a wider framework for language generation as a whole, whereupon we show how the representation language can be successfully used to produce appropriate referring expressions for a range of complex object types.Amongst the more important ideas explored in the thesis are the following:• We introduce the notion of a generalized physical object as a way of representing singular entities, mass entities, and entities which are sets.• We adopt the view that planning operators are essentially underspecified events, and use this, in conjunction with a simple model of the hearer, to allow us to determine the appropriate level of detail at which a given plan should be described.• We make use of a discourse model that distinguishes local and global focus, and is closely tied to a notion of discourse structure; and we introduce a notion of DISCRIMINATORY POWER as a means to choosing the content of a referring expression.• We present a model of the generation of referring expressions that makes use of two levels of intermediate representation, and integrate this model with the use of a linguistically- founded grammar for noun phrases.The thesis ends by making some suggestions for further extensions to the work reported here

Generation of anaphors in Chinese

The goal of this thesis is to investigate the computer generation of various kinds of anaphors in Chinese, including zero, pronominal and nominal anaphors, from the se¬ mantic representation of multisentential text. The work is divided into two steps: the first is to investigate linguistic behaviour of Chinese anaphora, and the other is to implement the result of the first part in a Chinese natural language generation system to see how it works.The first step is in general to construct a set of rules governing the use of all kinds of anaphors. To achieve this, we performed a sequence of experiments in a stepwise refined manner. In the experiments, we examined the occurrence of anaphors in humangenerated text and those generated by algorithms employing the rules, assuming the same semantic and discourse structures as the text. We started by distinguishing between the use of zero and other anaphors, termed non-zeroes. Then we performed experiments to distinguish between pronouns and nominal anaphors within the nonzeroes. Finally, we refined the previous result to consider different kinds of descriptions for nominal anaphors. In this research we confine ourselves to descriptive texts. Three sets of test data consisting of scientific questions and answers and an introduction to Chinese grammar were selected. The rules we obtained from the experiments make use of the following conditions: locality between anaphor and antecedent, syntactic constraints on zero anaphors, discourse segment structures, salience of objects and animacy of objects. The results show that the anaphors generated by using the rules we obtained are very close to those in the real texts.To carry out the second step, we built up a Chinese natural language generation system which is able to generate descriptive texts. The system is divided into a strategic and a tactical component. The strategic component arranges message contents in response to the input goal into a well-organised hierarchical discourse structure by using a text planner. The tactical component takes the hierarchical discourse structure as input and produces surface sentences with punctuation marks inserted appropriately. Within the tactical component, the first task consists of linearising in depth-first order the message units in the discourse structure and mapping them into syntactic-oriented representations. Referring expressions, the main concern in this thesis, are generated within the mapping process. A linguistic realisation program is then invoked to convert the syntactic representation into surface strings in Chinese.After the implementation, we sent some generated texts to a number of native speakers of Chinese and compared human-created results and computer-generated text to investigate the quality of the generated anaphors. The results of the comparison show that the rules we obtained are effective in dealing with the generation of anaphors in Chinese