知識組織工具（四）索引典 (Thesaurus)

知識組織工具（四）索引典 (Thesaurus) 藍文欽 Lanw@ccms.ntu.edu.tw 05/15/2003

Prelude • 索引典是字彙控制(vocabulary control)的工具之一。 • 索引典是索引用語及檢索詞彙的authority list。 • 索引典是由已知的概念查得代表該概念的適當用語。[concept  term] • 索引典透過標準化詞彙的選用，使同一概念產生類聚(grouping)的作用。

Introduction • Thesaurus 的原義為：Treasury, Collection • 通常用於同義字字典。 “A book of words and their synonyms”（Merriam-Webster’s Dictionary） “A book of words that are put in groups together according to connections between their meanings rather than in an alphabetical list.” (Longman Dictionary of Contemporary English) • e.g., Roget’s Thesaurus of English Words and Phrases • 1957AD – H. P. Luhn最早以Thesaurus代表「主題索引用語辭典」（簡稱索引典），並以之為字彙控制的工具。（一說Brownson於1957正式使用索引典一詞）

Definition “The vocabulary of a controlled indexing language, formally organized so that the a priori relationships between concepts (for example as “broader” and “narrower”) are made explicit. “ (Source: Guidelines for the establishment and development of monolingual thesauri, ISO 2788:1986)

Definition (cont.) “A thesaurus may be defined either in terms of its function or its structure. In terms of function, a thesaurus is a terminological control device used in translating from the natural language of documents, indexers or users into a more constrained “system language” (documentation language, information language). In terms of structure, a thesaurus is a controlled and dynamic vocabulary of a controlled and dynamic vocabulary of semantically and generically related terms which covers a specific domain of knowledge.” (Source: Unesco. The UNISIST Guidelines for the Establishment and Development of Monolingual Thesauri)

Definition (cont.) • “A compilation of words and phrases showing synonymous, hierarchical, and other relationships and dependencies, the function of which is to provide a standardized vocabulary for information storage and retrieval. “ • “A controlled vocabulary arranges in a known order in which equivalence, homographic, hierarchical, and associative relationships among terms are clearly displayed and identified by standardized relationship indicator, which must be employed reciprocally.” (Source: Guidelines for the Construction, Format, and Management of Monolingual Thesauri Document Number, ANSI/NISO Z39.19-1993)

Definition (cont.) A thesaurus in the field of information storage and retrieval is a list of terms and/or of other signs (or symbols) indicating relationships among these elements, provided that the following criteria hold: • the list contains a significant proportion of non-preferred terms and/or of preferred terms not used as descriptors; • terminological control is intended. (Source: Dagobert Soergel. Indexing Languages and Thesarui: Construction and Maintenance. Los Angeles: Melville, 1974. p. 38-39.)

Definition (cont.) 「就資訊儲存與檢索的範疇而言，索引典乃收集足以表示知識概念的字或詞，並將之以特定的結構加以排列，這些字彙控制了同義字，區別了同形異義字，並顯現各相關詞彙間階層及語意互屬上的各種關係，以作為索引者在分析處理資料及讀者在檢索資料時能選用一致的、經過控制的詞彙。換言之，及提供資訊儲存與檢索標準化的用語。」（Source: 蔡明月。線上資訊檢索—理論與應用。台北：台灣學生，民80。頁177。）

Brief History • 1959 – the Engineering Information Center of E. I. Dupont de Nemours developed the first true thesaurus • 1960 – the Armed Services Technical Information Agency (ASTIA) produced the Thesaurus of ASTIA Descriptors • 1961 – the American Institute of Chemical Engineers (AIChE) published the Chemical Engineering Thesaurus • 1964 – the Engineers Joint Council (EJC) published the Thesaurus of Engineering Terms • 1967 –Thesaurus of Engineering and Scientific Terms (TEST)

Brief History (cont.) • 1967 – the Committee on Scientific and Technical Information (COSATI) published the first set of guidelines for thesaurus construction • 1970 – Unesco Guidelines for the Establishment and Development f Monolingual Scientific and Technical Thesaurus • 1974 – ANSI (American National Standards Institute) Z39.19 [a US national standard for thesaurus construction] • 1974 – the first international standard for thesaurus construction – ISO 2788

Purposes and Use of Thesauri • “Its purposes are to promoted consistency in the indexing of documents, predominantly for postcoordinated information storage and retrieval systems, and to facilitate searching by linking entry terms with descriptors” (ANSI Z39.19-1993, p. 38) • Four principal purposes are served by a thesaurus: • Translation. To provide a means for translating the natural language of authors, indexers, and users into a controlled vocabulary used for indexing and retrieval. • Consistency. To promote consistency in the assignment of index terms. • Indication of Relationships. To indicate semantic relationships among terms. • Retrieval To serve as a searching aid in retrieval of documents. (ANSI Z39.19-1993, p. 1)

Vocabulary Control The need to control the formation and use of terms stems mainly from two basic features of natural language: Synonyms– different terms representing the same concept Polysemes– a word with multiple meanings [in spoken language, polysemes are homonyms; in written language, they are homographs– terms with the same spelling representing different concepts. Only the latter is relevant to thesauri.]

Vocabulary Control (cont.) Vocabulary control in a thesaurus is achieved through three principal means: • the delineation of the scope, or meaning, of descriptors  Scope Note (SN) • the linking of synonymous and nearly (quasi) synonymous terms through equivalence relationship  USE and UF • the disambiguation of homographs  Qualifier (Source: ANSI Z39.19-1993, p. 1)

Structure and Relationships • An intrinsic feature of a thesaurus is its ability to distinguish and display the structural relationships between the terms it contains. • There are two broad types of relationships within a thesaurus: • Micro Level – the semantic links between individual terms • Macro level – how the terms and their inter-relationships relate to the overall structure of the subject field (Source: J. Aitchison, A. Gilchrist, & D. Bawden. Thesaurus Construction and Use: A Practical Manual. 3rd ed. London: Aslib, 1997. P. 47)

Basic Thesaural Relationships Three basic inter-term relationships: • Equivalence: the relationship between preferred and non-preferred terms where two or more terms are regarded, for indexing purposes, as referring to the same concept • Hierarchical: this relationship shows levels of superordination and subordination. The superordinate term represents a class or whole, and the subordinate terms refer to its members or parts • Associative: the relationship is found between terms which are closely related conceptually but not hierarchically and are not members of an equivalence set. (本頁及以下關於各種relationship的敘述，主要參考: Aitchison, Gilchrist, & Bawden, 1997, Section F)

Equivalence Relationships • Descriptors – Preferred terms • Lead-in terms (Entry terms) – Non-preferred terms • Lead-in term USE DESCRIPTOR • DESCRIPTOR UF Lead-in term • Example: 耗子 USE 老鼠 (preferred term) 老鼠 UF 耗子 (non-preferred term)

Equivalence Relationships (cont.) • Synonyms – terms are virtually interchangeable or regarded as the same • Popular names and scientific names • Common nouns or scientific names, and trade names • Standard names and slang • Terms originating from different cultures sharing a common language (e.g., pavements/sidewalks) • Competing names for emerging concepts (e.g., metadata之各種中譯名) • Current or favored term versus outdated or deprecated term (e.g. dishwashers/washing-up machines)

Equivalence Relationships (cont.) • Lexical variants – different word forms for the same expressing, such as spelling, grammatical variation, irregular plurals, direct versus indirect order, and abbreviated formats • Variant spellings e.g., moslems/muslims; mouse/mice; colour/color • Direct and indirect form e.g, academic library vs. library, academic • Abbreviations and full names e.g., ALA vs. American Library Association

Equivalence Relationships (cont.) • Quasi-synonyms, or near-synonyms – terms whose meanings are generally regarded as different in ordinary usage, but they are treated as though they are synonyms for indexing purposes. • Terms having a significant overlap e.g., urban areas/cities gifted people/geniuses • Antonyms or terms representing different viewpoints of the same property continuum e.g., dryness/wetness equality/inequality

Equivalence Relationships (cont.) • Upward posting (generic posting) – This is a technique which treats narrower terms as if they are equivalent to, rather than a species of, their broader terms. The effect is to reduce the size of the vocabulary. • SOCIAL CLASS UF Elite Middle class Working class …… • Elite USE SOCIAL CLASS

Hierarchical Relationships The relationship is reciprocal and is set out in a thesaurus using the following conventions: BT (Broader Term) NT (Narrower Term) e.g., Public Libraries BT Libraries Libraries NT Academic Libraries Children’s Libraries Public Libraries ……

Hierarchical Relationships (cont.) • Generic/species relationship – identifies the link between a class or category and its members or species (e.g., Bird / Robin) • Whole/part relationship • Systems and organs of the body (e.g., 消化系統 / 胃) • Geographical location (e.g., Taipei / Ta-an District) • Discipline or field of study (e.g., Chemistry / Organic chemistry) • Hierarchical social structure (e.g., army and its rank system)

Hierarchical Relationships (cont.) • Instance relationship – a general category of things and events, expressed by a common noun, and an individual instance of that category, the instance then forming a class of one which is represented by a proper name (e.g., SEAS / Pacific Ocean) • Polyhierarchical relationships – the relationship between the term and its two or more superordinate terms is said to be polyhierarchical. NURSES HEALTH ADMINISTRATORS NT Nurse Administrators NT Nurse Administrators NURSES ADMINISTRATORS BT Health administrators Nurses

Associative Relationships • The relation is reciprocal, and is distinguished by the abbreviation “RT” (Related Terms) e.g., TEACING RT Teaching aids TEACHING AIDS RT Teaching

Associative Relationships (cont.) Two types of associative relationship: • Terms belonging to the same category (e.g., motorcycle / bicycle) • Terms belonging to different categories • Whole-part (e.g., buildings / doors) • A discipline and the objects studied (e.g., ethnography / primitive societies) • An operation or process and the agent or instrument (e.g., motor racing / racing cars) • An occupation and the person in that occupation (e.g., accountancy / accountants) • An action and the product of the action (e.g., publishing / music scores)

Associative Relationships (cont.) • Terms belonging to different categories (cont.) • An action and its patient (e.g., data analysis / data) • Concepts related to their properties (e.g., women / femininity) • Concepts linked by causal dependence (e.g., injury / accidents) • A thing or action and its counter-agent (e.g., pests / pesticides) • A raw material and its product (e.g., 皮革 / 皮衣) • An action and a property associated with it (e.g., precision measurement / accuracy) • A concept and its opposite (e.g., single people / married people)

A Sample Thesaurus Entry –from Thesaurus of ERIC Descriptors COMPETENCY BASED EDUCATION Mar. 1980 CIJE: 884 RIE: 2881 GC: 330 SN Educational system that emphasizes the specification, learning, and demonstrating of those competencies (knowledge, skills, behaviors) that are of central importance to a given task, activity, or career. UF Consequence Based Education Criterion Referenced Education Output Oriented Education NT Competency Based Teacher Education BT Education RT Academic Standards Accountability Back to Basics Individualized Instruction ……

Display • Alphabetical • Classified • Hierarchical • Permuted Keyword Index • Graphical （詳見課堂上所印發之講義）

Planning and Design of Thesauri – Two Check Points • Is a thesaurus necessary? • If it is, which of the followings would be a better or more suitable approach? • Buying • Compiling • Adapting • A very useful Web site to find information about thesaurus construction and use – prepared by Willpower Information http://www.willpower.demon.co.uk/thesbibl.htm

Planning and Design of Thesauri –Information System Considerations • Subject field • Type of literature/data • Quantity of literature/data • Language considerations • System users • Questions, searchers, profiles • Resources available (Source: Aitchison, Gilchrist, & Bawden, 1997, Section B)

How to Build a Thesaurus – The Top-Down Method • Convene a group of subject experts to decide on the scope and broad categories of terms to be included. • Use existing dictionaries and thesauri to decide on the terms and their relationships. • Review and organize the preliminary term set: decide on preferred terms and make Use references from the variants and synonyms; and build hierarchical and associative relationships among the preferred terms. • Produce a draft thesaurus, test index and revise. (source: http://www.asindexing.org/site/thesbuild.shtml)

How to Build a Thesaurus – The Bottom-up Method • Develop a group of subject experts to serve as advisors; work with them to determine the scope if it is not already set. • If there is a set of representative already-indexed documents, use the index terms from this set as your preliminary term list. • If not, index a set of representative documents using free language (i.e., no vocabulary control), and take this term set as your preliminary list. • Build your thesaurus by reviewing and organizing these terms, using a variety of resources as aids, as in the top-down method. • Refer to your subject experts on terms whose meaning or usage is unclear, and for advice on which variant or synonym to prefer (or on whether two terms really are synonyms in the field). • Produce a draft thesaurus, test index, and revise. (Source: http://www.asindexing.org/site/thesbuild.shtml)

Procedures Involved in Thesaurus Construction • Collecting terms • Modifying and inventing terms • Choosing preferred terms and standardizing the form of words • Establishing semantic relationships • Thesaurus arrangement and display • Testing and revising • Thesaurus maintenance The American Society of Indexers provides a list of thesaurus management software -- http://www.asindexing.org/site/thessoft.shtml

Standard • The UNISIST Guidelines for the Establishment and Development of Monolingual Thesauri. 2nd rev. ed.(Paris: UNESCO, 1981) • Guidelines for the establishment and development of monolingual thesauri, ISO 2788:1986 (http://www.nlc-bnc.ca/iso/tc46sc9/standard/2788e.htm) • Guidelines for the establishment and development of multilingual thesauri, ISO 5964: 1985 (http://www.nlc-bnc.ca/iso/tc46sc9/standard/5964e.htm)

Standard (cont.) • Guidelines for the Construction, Format, and Management of Monolingual Thesauri Document Number, ANSI/NISO Z39.19-1993 (R1998) (http://www.niso.org/standards/resources/Z39-19.html) • Guidelines for Forming Language Equivalents: A Model Based on the Art & Architecture Thesaurus, prepared by International Terminology Working Group, 1999(http://www.chin.gc.ca/Resources/Publications/Guidelines/English/index.html) • 西方單一語文索引典編製標準（CNS 13224）

Examples • 農業科技索引典 • 水資源索引典 • 立法資訊系統主題索引典 http://lis.ly.gov.tw/lghtml/crshelp/search.htm • 食品科技索引典 • 科技索引典 • 中文教育類詞庫 (http://140.122.127.251/ttscgi/ttsweb1?@0:0:1:ericthe::http|//140.122.127.251/edd/edd.htm@@0.57560553)

Examples (cont.) • Unesco Thesaurus: A Structured List of Descriptors for Indexing and Retrieving Literature in the Fields of Education, Science, Social and Human Science, Culture, Communication and Information. • The Unesco: IBE Education Thesaurus • Thesaurus of ERIC Descriptors • Thesaurus of Sociological Research Terminology • Thesaurus of Sociological Indexing Terms

Examples (cont.) • Arts and Architecture Thesaurus (http://www.getty.edu/research/tools/vocabulary/aat/index.html) • Thesaurus of Graphic Materials I: Subject Terms (TGM I)(http://www.loc.gov/rr/print/tgm1/) • Thesaurus for Graphic Materials II: Genre and Physical Characteristic Terms (TGM II) (http://www.loc.gov/rr/print/tgm2/) • British Museum Materials Thesaurus(http://www.mda.org.uk/bmmat/matintro.htm) • Vocabulary of Basic Terms for Cataloguing Costume (http://www.mda.org.uk/costume/vbt00e.htm)

Examples (cont.) • British Museum Object Names Thesaurus • Union List of Artist Names (ULAN)http://www.getty.edu/research/tools/vocabulary/ulan/index.html • Thesaurus of Geographic Names (TGN)http://www.getty.edu/research/tools/vocabulary/tgn/ • Thesaurus of Monument Types • mda Archaeological Objects Thesaurus • Building Materials Thesaurus • INSCRIPTION(http://www.mda.org.uk/fish/i_lists.htm)

Examples (cont.) • Macrothesaurus for Information Processing in the Field of Economic and Social Development • Social Science and Business Microthesaurus: A Hierarchical List of Indexing Terms Used by NTIS • Political Science Thesaurus • SPINES Thesaurus: A Controlled and Structured Vocabulary of Science and Technology for Policy Making • Thesaurus of Psychological Index Terms

Examples (cont.) • Thesaurus of Engineering and Scientific Terms (TEST) • INSPEC Thesaurus • NASA Thesaurus • Thesaurus of Computing Terms • Thesaurus of Scientific, Technical and Engineering Terms • International Road Research Documentation (IRRD) Thesaurus • Construction Industry Thesaurus

Examples (cont.) • ASIS Thesaurus of Information Science and Librarianship • Thesaurus of Information Science Terminology • Zoological Record Online Thesaurus • Food: Multilingual Thesaurus • Thesaurus of Agricultural Terms • Medical Subject Headings (MeSH) • The ISDD Thesaurus. Keywords Relating to Non-Medical Use of Drugs and Drug Dependence

知識組織工具（四）索引典 (Thesaurus)