http://hdl.handle.net/2436/7576 Thu, 23 May 2013 11:20:30 GMT 2013-05-23T11:20:30Z http://hdl.handle.net/2436/27900 Title: Discovery of event entailment knowledge from text corpora Authors: Pekar, Viktor Abstract: Event entailment is knowledge that may prove useful for a variety of applications dealing with inferencing over events described in natural language texts. In this paper, we propose a method for automatic discovery of pairs of verbs related by entailment, such as X buy Y X own Y and appoint X as Y X become Y. In contrast to previous approaches that make use of lexico-syntactic patterns and distributional evidence, the underlying assumption of our method is that the implication of one event by another manifests itself in the regular co-occurrence of the two corresponding verbs within locally coherent text. Based on the analogy with the problem of learning selectional preferences Resnik’s [Resnik, P., 1993. Selection and information: a class-based approach to lexical relationships, Ph.D. Thesis, University of Pennsylvania] association strength measure is used to score the extracted verb pairs for asymmetric association in order to discover the direction of entailment in each pair. In our experimental evaluation, we examine the effect that various local discourse indicators produce on the accuracy of this model of entailment. After that we carry out a direct evaluation of the verb pairs against human subjects’ judgements and extrinsically evaluate the pairs on the task of noun phrase coreference resolution. Tue, 01 Jan 2008 00:00:00 GMT http://hdl.handle.net/2436/27900 2008-01-01T00:00:00Z http://hdl.handle.net/2436/27899 Title: Design and development of a concept-based multi-document summarization system for research abstracts Authors: Ou, Shiyan; Khoo, Christopher S.G.; Goh, Dion H. Abstract: This paper describes a new concept-based multi-document summarization system that employs discourse parsing, information extraction and information integration. Dissertation abstracts in the field of sociology were selected as sample documents for this study. The summarization process includes four major steps — (1) parsing dissertation abstracts into five standard sections; (2) extracting research concepts (often operationalized as research variables) and their relationships, the research methods used and the contextual relations from specific sections of the text; (3) integrating similar concepts and relationships across different abstracts; and (4) combining and organizing the different kinds of information using a variable-based framework, and presenting them in an interactive web-based interface. The accuracy of each summarization step was evaluated by comparing the system-generated output against human coding. The user evaluation carried out in the study indicated that the majority of subjects (70%) preferred the concept-based summaries generated using the system to the sentence-based summaries generated using traditional sentence extraction techniques. Tue, 01 Jan 2008 00:00:00 GMT http://hdl.handle.net/2436/27899 2008-01-01T00:00:00Z http://hdl.handle.net/2436/27898 Title: Automatic multidocument summarization of research abstracts: Design and user evaluation Authors: Ou, Shiyan; Khoo, Christopher S.G.; Goh, Dion H. Abstract: The purpose of this study was to develop a method for automatic construction of multidocument summaries of sets of research abstracts that may be retrieved by a digital library or search engine in response to a user query. Sociology dissertation abstracts were selected as the sample domain in this study. A variable-based framework was proposed for integrating and organizing research concepts and relationships as well as research methods and contextual relations extracted from different dissertation abstracts. Based on the framework, a new summarization method was developed, which parses the discourse structure of abstracts, extracts research concepts and relationships, integrates the information across different abstracts, and organizes and presents them in a Web-based interface. The focus of this article is on the user evaluation that was performed to assess the overall quality and usefulness of the summaries. Two types of variable-based summaries generated using the summarization method - with or without the use of a taxonomy - were compared against a sentence-based summary that lists only the research-objective sentences extracted from each abstract and another sentence-based summary generated using the MEAD system that extracts important sentences. The evaluation results indicate that the majority of sociological researchers (70%) and general users (64%) preferred the variable-based summaries generated with the use of the taxonomy. Mon, 01 Jan 2007 00:00:00 GMT http://hdl.handle.net/2436/27898 2007-01-01T00:00:00Z http://hdl.handle.net/2436/27897 Title: Multi-document summarization of news articles using an event-based framework Authors: Ou, Shiyan; Khoo, Christopher S.G.; Goh, Dion H. Abstract: Purpose – The purpose of this research is to develop a method for automatic construction of multi-document summaries of sets of news articles that might be retrieved by a web search engine in response to a user query. Design/methodology/approach – Based on the cross-document discourse analysis, an event-based framework is proposed for integrating and organizing information extracted from different news articles. It has a hierarchical structure in which the summarized information is presented at the top level and more detailed information given at the lower levels. A tree-view interface was implemented for displaying a multi-document summary based on the framework. A preliminary user evaluation was performed by comparing the framework-based summaries against the sentence-based summaries. Findings – In a small evaluation, all the human subjects preferred the framework-based summaries to the sentence-based summaries. It indicates that the event-based framework is an effective way to summarize a set of news articles reporting an event or a series of relevant events. Research limitations/implications – Limited to event-based news articles only, not applicable to news critiques and other kinds of news articles. A summarization system based on the event-based framework is being implemented. Practical implications – Multi-document summarization of news articles can adopt the proposed event-based framework. Originality/value – An event-based framework for summarizing sets of news articles was developed and evaluated using a tree-view interface for displaying such summaries. Sun, 01 Jan 2006 00:00:00 GMT http://hdl.handle.net/2436/27897 2006-01-01T00:00:00Z