Search (14 results, page 1 of 1)

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Abstract

In a changing information environment, we need to reassess each element of bibliographic control, including classification theories and systems. Every classification system is a theoretical construct imposed an "reality." The classificatory relationships that are assumed to be valuable have generally received less attention than the topics included in the systems. Relationships are functions of both the syntactic and semantic axes of classification systems, and both explicit and implicit relationships are discussed. Examples are drawn from a number of different systems, both bibliographic and non-bibliographic, and the cultural warrant (i. e., the sociocultural context) of classification systems is examined. The part-whole relationship is discussed as an example of a universally valid concept that is treated as a component of the cultural warrant of a classification system.

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Source

Knowledge organization, information systems and other essays: Professor A. Neelameghan Festschrift. Ed. by K.S. Raghavan and K.N. Prasad

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Abstract

Classical knowledge representation methods have been successfully working for years with established - but in a way restricted and vague - relations such as synonymy, hierarchy (meronymy, hyponymy) and unspecified associations. Recent developments like ontologies and folksonomies show new forms of collaboration, indexing and knowledge representation and encourage the reconsideration of standard knowledge relationships for practical use. In a summarizing overview we show which relations are currently used in knowledge organization systems (controlled vocabularies, ontologies and folksonomies) and which relations are expressed explicitly or which may be inherently hidden in them.

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Date

22. 9.2007 15:45:57

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Abstract

Purpose - The purpose of this paper is to summarize the varied structural characteristics which may be present in retrieval languages. Design/methodology/approach - The languages serve varied purposes in information systems, and a number of these are identified. The relations between structure and function are discussed and suggestions made as to the most suitable structures needed for various purposes. Findings - A quantitative approach has been developed: a simple measure is the number of separate terms in a retrieval language, but this has to be related to the scope of its subject field. Some ratio of terms to items in the field seems a more suitable measure of the average specificity of the terms. Other aspects can be quantified - for example, the average number of links in hierarchical chains, or the average number of cross-references in a thesaurus. Originality/value - All the approaches to the analysis of retrieval language reported in this paper are of continuing value. Some practical studies of computer information systems undertaken by Aslib Research Department have suggested a further approach.

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Abstract

The structure of terminology systems can be seen as one way to organize knowledge. This paper focuses an three types of relationships among terms: synonymy, hierarchical relationships, and explicit mapping relationships. Examples drawn from various medical vocabularies illustrate each type of relationship. The integration of disparate terminological knowledge structures in the Unified Medical Language System is presented and discussed.

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Abstract

The basic elements of faceted thesauri are described, together with a review of their origins and some prominent examples. Their use in browsing and searching applications is discussed. Faceted thesauri are distinguished from faceted classification schemes, while acknowledging the close similarities. The paper concludes by comparing faceted thesauri and related knowledge organization systems to ontologies and discussing appropriate areas of use.

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Abstract

Extracting semantic relationships between entities from text documents is challenging in information extraction and important for deep information processing and management. This paper investigates the incorporation of diverse lexical, syntactic and semantic knowledge in feature-based relation extraction using support vector machines. Our study illustrates that the base phrase chunking information is very effective for relation extraction and contributes to most of the performance improvement from syntactic aspect while current commonly used features from full parsing give limited further enhancement. This suggests that most of useful information in full parse trees for relation extraction is shallow and can be captured by chunking. This indicates that a cheap and robust solution in relation extraction can be achieved without decreasing too much in performance. We also demonstrate how semantic information such as WordNet, can be used in feature-based relation extraction to further improve the performance. Evaluation on the ACE benchmark corpora shows that effective incorporation of diverse features enables our system outperform previously best-reported systems. It also shows that our feature-based system significantly outperforms tree kernel-based systems. This suggests that current tree kernels fail to effectively explore structured syntactic information in relation extraction.

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Abstract

This article deals with the meaningful processing of information in relation to two systems of Information processing: pre-coordination and post-coordination. The different approaches are discussed, with emphasis an the need for a controlled vocabulary in information retrieval. Assigned indexing, which employs a controlled vocabulary, is described in detail. Types of indexing language can be divided into two broad groups - those using pre-coordinated terms and those depending an post-coordination. They represent two different basic approaches in processing and Information retrieval. The historical development of these two approaches is described, as well as the two tools that apply to these approaches: thesauri and subject headings.

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Abstract

The IFLA Section on Classification and Indexing's Working Group on Principles Underlying Subject Headings Languages has identified a set of eleven principles for subject heading languages and excerpted the texts that match each principle from the instructions for each of eleven national subject indexing systems, including excerpts from the LC's Subject Cataloging Manual: Subject Headings. This study compares the IFLA principles with other texts that express the principles underlying LCSH, especially Library of Congress Subject Headings: Principles of Structure and Policies for Application, prepared by Lois Mai Chan for the Library of Congress in 1990, Chan's later book on LCSH, and earlier documents by Haykin and Cutter. The principles are further elaborated for clarity and discussed

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Abstract

Relationships between the terms in thesauri and Indexes are the subject of national and international standards. The standards for thesauri enumerate and provide criteria for three basic types of relationship: equivalence, hierarchical, and associative. Standards and guidelines for indexes draw an the thesaurus standards to provide less detailed guidance for showing relationships between the terms used in an Index. The international standard for multilingual thesauri adds recommendations for assuring equal treatment of the languages of a thesaurus. The present standards were developed when lookup and search were essentially manual, and the value of the kinds of relationships has never been determined. It is not clear whether users understand or can use the distinctions between kinds of relationships. On the other hand, sophisticated text analysis systems may be able both to assist with development of more powerful term relationship schemes and to use the relationships to improve retrieval.

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Abstract

Classification schemes, thesauri, taxonomies, and other controlled vocabularies play important roles in the organization and retrieval of information in many different environments. While the design and construction of controlled vocabularies have been prescribed at the technical level in great detail over the past decades, the methodological level has been somewhat neglected. However, classification research has in recent years focused on developing approaches to the analysis of users, domains, and activities that could produce requirements for the design of controlled vocabularies. Researchers have often argued that the design, construction, and use of controlled vocabularies need to be based on analyses and understandings of the contexts in which these controlled vocabularies function. While one would assume that the growing body of research on human information behavior might help guide the development of controlled vocabularies shed light on these contexts, unfortunately, much of the research in this area is descriptive in nature and of little use for systems design. This paper discusses these trends and outlines a holistic approach that demonstrates how the design of controlled vocabularies can be informed by investigations of people's interactions with information. This approach is based on the Cognitive Work Analysis framework and outlines several dimensions of human-information interactions. Application of this approach will result is a comprehensive understanding of the contexts in which the controlled vocabulary will function and which can be used for the development of for the development of controlled vocabularies.

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Abstract

The current standards for monolingual and multilingual thesauri are long overdue for an update. This applies to the international standards ISO 2788 and ISO 5964, as well as the corresponding national standards in several countries and the American standard ANSI/NISO Z39.19. Work is now under way in the UK and in the USA to revise and extend the standards, with particular emphasis on interoperability needs in our world of vast electronic networks. Work in the UK is starting with the British Standards, in the hope of leading on to one international standard to serve all. Some of the issues still under discussion include the treatment of facet analysis, coverage of additional types of controlled vocabulary such as classification schemes, taxonomies and ontologies, and mapping from one vocabulary to another. 1. Are thesaurus standards still needed? Since the 1960s, even before the renowned Cranfield experiments (Cleverdon et al., 1966; Cleverdon, 1967) arguments have raged over the usefulness or otherwise of controlled vocabularies. The case has never been proved definitively one way or the other. At the same time, a recognition has become widespread that no one search method can answer all retrieval requirements. In today's environment of very large networks of resources, the skilled information professional uses a range of techniques. Among these, controlled vocabularies are valued alongside others. The first international standard for monolingual thesauri was issued in 1974. In those days, the main application was for postcoordinate indexing and retrieval from document collections or bibliographic databases. For many information professionals the only practicable alternative to a thesaurus was a classification scheme. And so the thesaurus developed a strong following. After computer systems with full text search capability became widely available, however, the arguments against controlled vocabularies gained more followers. The cost of building and maintaining a thesaurus or a classification scheme was a strong disincentive. Today's databases are typically immense compared with those three decades ago. Full text searching is taken for granted, not just in discrete databases but across all the resources in an intranet or even the Internet. But intranets have brought particular frustration as users discover that despite all the computer power, they cannot find items which they know to be present an the network. So the trend against controlled vocabularies is now being reversed, as many information professionals are turning to them for help. Standards to guide them are still in demand.

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Abstract

Linguists in the structuralist tradition (e.g., Lyons, 1977; Saussure, 1959) have asserted that concepts cannot be defined on their own but only in relation to other concepts. Semantic relations appear to reflect a logical structure in the fundamental nature of thought (Caplan & Herrmann, 1993). Green, Bean, and Myaeng (2002) noted that semantic relations play a critical role in how we represent knowledge psychologically, linguistically, and computationally, and that many systems of knowledge representation start with a basic distinction between entities and relations. Green (2001, p. 3) said that "relationships are involved as we combine simple entities to form more complex entities, as we compare entities, as we group entities, as one entity performs a process on another entity, and so forth. Indeed, many things that we might initially regard as basic and elemental are revealed upon further examination to involve internal structure, or in other words, internal relationships." Concepts and relations are often expressed in language and text. Language is used not just for communicating concepts and relations, but also for representing, storing, and reasoning with concepts and relations. We shall examine the nature of semantic relations from a linguistic and psychological perspective, with an emphasis on relations expressed in text. The usefulness of semantic relations in information science, especially in ontology construction, information extraction, information retrieval, question-answering, and text summarization is discussed. Research and development in information science have focused on concepts and terms, but the focus will increasingly shift to the identification, processing, and management of relations to achieve greater effectiveness and refinement in information science techniques. Previous chapters in ARIST on natural language processing (Chowdhury, 2003), text mining (Trybula, 1999), information retrieval and the philosophy of language (Blair, 2003), and query expansion (Efthimiadis, 1996) provide a background for this discussion, as semantic relations are an important part of these applications.