Search (10 results, page 1 of 1)

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Abstract

A relevancy-ranking algorithm for a natural language interface to Boolean online public access catalogs (OPACs) was formulated and compared with that currently used in a knowledge-based search interface called the E-Referencer, being developed by the authors. The algorithm makes use of seven weIl-known ranking criteria: breadth of match, section weighting, proximity of query words, variant word forms (stemming), document frequency, term frequency and document length. The algorithm converts a natural language query into a series of increasingly broader Boolean search statements. In a small experiment with ten subjects in which the algorithm was simulated by hand, the algorithm obtained good results with a mean overall precision of 0.42 and mean average precision of 0.62, representing a 27 percent improvement in precision and 41 percent improvement in average precision compared to the E-Referencer. The usefulness of each step in the algorithm was analyzed and suggestions are made for improving the algorithm.

Content

"Most Web search engines accept natural language queries, perform some kind of fuzzy matching and produce ranked output, displaying first the documents that are most likely to be relevant. On the other hand, most library online public access catalogs (OPACs) an the Web are still Boolean retrieval systems that perform exact matching, and require users to express their search requests precisely in a Boolean search language and to refine their search statements to improve the search results. It is well-documented that users have difficulty searching Boolean OPACs effectively (e.g. Borgman, 1996; Ensor, 1992; Wallace, 1993). One approach to making OPACs easier to use is to develop a natural language search interface that acts as a middleware between the user's Web browser and the OPAC system. The search interface can accept a natural language query from the user and reformulate it as a series of Boolean search statements that are then submitted to the OPAC. The records retrieved by the OPAC are ranked by the search interface before forwarding them to the user's Web browser. The user, then, does not need to interact directly with the Boolean OPAC but with the natural language search interface or search intermediary. The search interface interacts with the OPAC system an the user's behalf. The advantage of this approach is that no modification to the OPAC or library system is required. Furthermore, the search interface can access multiple OPACs, acting as a meta search engine, and integrate search results from various OPACs before sending them to the user. The search interface needs to incorporate a method for converting the user's natural language query into a series of Boolean search statements, and for ranking the OPAC records retrieved. The purpose of this study was to develop a relevancyranking algorithm for a search interface to Boolean OPAC systems. This is part of an on-going effort to develop a knowledge-based search interface to OPACs called the E-Referencer (Khoo et al., 1998, 1999; Poo et al., 2000). E-Referencer v. 2 that has been implemented applies a repertoire of initial search strategies and reformulation strategies to retrieve records from OPACs using the Z39.50 protocol, and also assists users in mapping query keywords to the Library of Congress subject headings."

Source

Electronic library. 22(2004) no.2, S.112-120

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Abstract

Khoo, Dai, and Loh examine new statistical methods for the identification of two and three character words in Chinese text. Some meaningful Chinese words are simple (independent units of one or more characters in a sentence that have independent meaning) but others are compounds of two or more simple words. In their segmentation they utilize the Modern Chinese Word Segmentation for Application of Information Processing, with some modifications to focus on meaningful words to do manual segmentation. About 37% of meaningful words are longer than 2 characters indicating a need to handle three and four character words. Four hundred sentences from news articles were manually broken into overlapping bi-grams and tri-grams. Using logistic regression, the log of the odds that such bi/tri-grams were meaningful words was calculated. Variables like relative frequency, document frequency, local frequency, and contextual and positional information, were incorporated in the model only if the concordance measure improved by at least 2% with their addition. For two- and three-character words relative frequency of adjacent characters and document frequency of overlapping bi-grams were found to be significant. Using measures of recall and precision where correct automatic segmentation is normalized either by manual segmentation or by automatic segmentation, the contextual information formula for 2 character words provides significantly better results than previous formulations and using both the 2 and 3 character formulations in combination significantly improves the 2 character results.

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Abstract

Purpose - Potential and benefits of classification schemes and thesauri in building organizational taxonomies cannot be fully utilized by organizations. Empirical data of building an organizational taxonomy by the top-down approach of using classification schemes and thesauri appear to be lacking. The paper seeks to make a contribution in this regard. Design/methodology/approach - A case study of building an organizational taxonomy was conducted in the information studies domain for the Division of Information Studies at Nanyang Technology University, Singapore. The taxonomy was built by using the Dewey Decimal Classification, the Information Science Taxonomy, two information systems taxonomies, and three thesauri (ASIS&T, LISA, and ERIC). Findings - Classification schemes and thesauri were found to be helpful in creating the structure and categories related to the subject facet of the taxonomy, but organizational community sources had to be consulted and several methods had to be employed. The organizational activities and stakeholders' needs had to be identified to determine the objectives, facets, and the subject coverage of the taxonomy. Main categories were determined by identifying the stakeholders' interests and consulting organizational community sources and domain taxonomies. Category terms were selected from terminologies of classification schemes, domain taxonomies, and thesauri against the stakeholders' interests. Hierarchical structures of the main categories were constructed in line with the stakeholders' perspectives and the navigational role taking advantage of structures/term relationships from classification schemes and thesauri. Categories were determined in line with the concepts and the hierarchical levels. Format of categories were uniformed according to a commonly used standard. The consistency principle was employed to make the taxonomy structure and categories neater. Validation of the draft taxonomy through consultations with the stakeholders further refined the taxonomy. Originality/value - No similar study could be traced in the literature. The steps and methods used in the taxonomy development, and the information studies taxonomy itself, will be helpful for library and information schools and other similar organizations in their effort to develop taxonomies for organizing content and aiding navigation on organizational sites.

Date

7.11.2008 15:22:04

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Abstract

A taxonomy is being developed to organize the content of a cultural heritage portal called Singapore Memory Portal, that provides access to a collection of memory postings about Singapore's history, culture, society, life/lifestyle and landscape/architecture. The taxonomy is divided into an upper-level taxonomy to support user browsing of topics, and a lower-level taxonomy to represent the types of information available on specific topics, to support user learning and information synthesis. The initial version of the upper-level taxonomy was developed based on potential users' expectations of the content coverage of the portal. The categories are centered on the themes of daily life/lifestyle, historically significant events, disasters and crises, festivals, a variety of cultural elements and national issues. The lower-level taxonomy was derived from attributes and relations extracted from essays and mindmaps produced by coders after reading memory postings for a sample of topics.

Source

Knowledge organization in the 21st century: between historical patterns and future prospects. Proceedings of the Thirteenth International ISKO Conference 19-22 May 2014, Kraków, Poland. Ed.: Wieslaw Babik

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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.

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Abstract

The various ways of improving the online catalog for subject searching are reviewed. The paper then discusses the expert system approach to developing a subject search front-end. It is suggested that an effective expert front-end can be developed by focusing on search strategies. A design for a rule-based expert system front-end is described. Possible search strategies and selection rules are illustrated. The inference structure of the system is based on Clancey's model of heuristic classification

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Date

12. 9.2004 9:56:22

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Content

An automated method for clustering terms/concepts from a set of documents on the same topic was developed for the purpose of multidocument summarization. The clustering method makes use of a combination of lexical overlap between multiword terms, syntactic constraints and semantic consideration based on a manually constructed taxonomy to generate hierarchically organized clusters of terms. This study evaluates the machine-generated clusters by calculating the proportion of overlap with two sets of human-generated clusters for 15 topics. It was found that the overlap between machine-generated clusters and individual human-generated clusters are higher than that between two human-generated clusters. A quailtative analysis of the human clustering found that clusters formed are either semantic-conceptual based or lexical based (similar to machine clustering). The semantic-conceptual based clusters that were formed tended to be different for different human coders. This has raised questions about whether machine-generated clustering can be evaluated by comparing with human clustering.

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Abstract

The Online Public Access Catalog (OPAC) is an information retrieval system characterized by short bibliographic records, mainly of books, journals, and audiovisual materials available in a particular library. This, coupled with a Boolean search interface and a heterogeneous user population with diverse needs, presents special problems for subject searching by end users. To perform effective subject searching in the OPAC system requires a wide range of knowledge and skills. Various approaches to improving the OPAC design for subject searching have been proposed and are reviewed in this entry. The trend toward Web-based OPAC interfaces and the developments in Internet and digital library technologies present fresh opportunities for enhancing the effectiveness of the OPAC system for subject searching.

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Abstract

This paper presents an evaluation study of the navigation effectiveness of a multifaceted organizational taxonomy that was built on the Dewey Decimal Classification and several domain thesauri in the area of library and information science education. The objective of the evaluation was to detect deficiencies in the taxonomy and to infer problems of applied construction steps from users' navigation difficulties. The evaluation approach included scenario-based navigation exercises and postexercise interviews. Navigation exercise errors and underlying reasons were analyzed in relation to specific components of the taxonomy and applied construction steps. Guidelines for the construction of the hierarchical structure and categories of an organizational taxonomy using existing general classification schemes and domain thesauri were derived from the evaluation results.