第二讲 信息组织方法论

1. 第二讲 信息组织方法论 第五章 主题法 刘炜 wliu@libnet.sh.cn

2. 主题法 • 直接以表示文献主题的语词作标识，提供字顺检索途径，并主要采用参照系统结石词间关系的标引和检索文献的方法。其中的语词可以是自然语言，也可以是受控语言。 （p.114）

3. 主题法的特点 • 揭示文献的内容属性 • 以自然语言为基础（不用标记制度） • 直接以局部（语词）指代文献 • 以特性检索为主，族性检索通过词间的关联达到 • 以明确性的检索为主，模糊检索通过技术的手段达到

4. 主题法的类型 • 标题法（Subject Heading） • 用规范化的自然语言语词作标题，直接表达文献主题概念，按照标题字顺排列，并用参照系统（已借鉴叙词表的参照关系：用代属分参）显示标题之间关系。 • 最早产生（1876年克特出版《字典式目录规则》） • 标题含义明确、易于使用 • 标题列举、先组式，概念表达能力有限，难以多向成族，检索途径少，标识的通用性差（由于采用自然语言？）

5. 主题法的类型 • 单元词法Uniterm • 又称元词法，以取自自然语言、经过规范化处理的语词作标识，通过子面组配表达主题。 • 最基本的、概念上不可再分解的词，表示文献主题 • 克服标题不足 • 后组式，易轮排（每个词）索引，灵活 • 20世纪50年代用于穿孔卡系统（最早的机检系统） • 字面分拆，语义准确性差 • 词间缺乏联系，缺乏参照系统

6. 主题法的类型 • 叙词法，又称主题词法Thesaurus • 以规范化的自然语言语词作为文献主题的标识，通过叙词的概念组配表达主题概念。 • 20世纪50年代末提出。吸取了元词法、标题法以及分面组配分类法的优点而发展起来 • 能够多向成族、多检索途径、多因素组配、灵活扩检/缩检/改变检索范围 • 灵活性、专指度、可扩展性俱佳

7. 主题法的类型 • 关键词法（又称自由词） • 直接以文献中能够表达主题概念的关键词作为标识。来自于计算机自动抽词 • 关键词：出现在文献的题名、文摘、正文中，能够表达文献主题，具有检索意义的语词。 • 自然语词，不做规范化处理（不受控） • 无词间关系，但编制禁用词表 • 现在计算机也能结合一定的受控功能，以提高检索的准确性

8. 叙词法的综合性 • 与元词法和标题法一样采用自然语言，但规范控制严格，保证标识与概念的唯一对应； • 适当采用标题法的预先组配，而不是元词法尽可能细分，以表达组合、专有概念，减少组配误差； • 借鉴分面组配分类法，采用概念组配而不是字面组配； • 完善了标题法的参照系统； • 采用体系分类法的叙词分类索引和等级索引（词族索引），甚至直接引入体系分类表或分面分类表，实现分类主题一体化； • 采用关键词法的轮排方法，编制叙词轮排索引

9. 主题法的功能 • 对信息内容进行标引的功能（指代用以检索）； • 对主题内容及其相关信息予以集中或揭示相关性的功能； • 对大量信息加以系统化或组织化的功能； • 便于将标引用语与检索用语进行相符性比较的功能

10. 叙词表 • 叙词表是词汇控制(vocabulary control)的工具之一。 • 叙词表是索引用语及检索词汇的authority list。 • 叙词表是由已知的概念查得代表该概念的适当用语。[concept  term] • 叙词表透过标准化词汇的选用，使同一概念产生类聚(grouping)的作用。

11. 《汉语主题词表》 • 1975 年，中国情报所、北京图书馆、国防科工委情报所、电子科技情报所、六二八所、机械科技情报所等单位组建全国1048个单位、7519人参加的《汉语主题词 表》研究编辑工作，是全国汉学信息处理系统工程（简称748工程）的组成部分，目的是建立全国统一的联机情报检索网络。该主题词表是中国第一部大型综合性 检索工具书，全书包括主表、附表、词族索引、范畴表、英汉对照索引等、共分3卷10个分册。其收词范围之广、编辑技术之先进、结构体系之严谨，当时是国内 外一流的。该成果获1985年国家科技进步二等奖。

12. 叙词表详解（略）

13. Introduction • Thesaurus 的原义为：Treasury, Collection • 通常用于同义字字典。 “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「主題索引用语词典」（简称叙词表），并以之为词汇控制的工具。（一說Brownson于1957正式使用叙词表一詞）

14. 叙词表的简要历史 • 1959年杜邦公司的工程信息中心开发了首个实用的序词表 • 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)

15. 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

16. 采用叙词表的目的 • 采用叙词表能够促进文本标引和后控情报存储和检索系统的一致性，并能够利用规范词进行搜索“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) • 采用叙词的四个主要目的Four principal purposes are served by a thesaurus: • 翻译Translation. 把作者、标引者和用户使用的自然语言翻译成受控规范词汇To provide a means for translating the natural language of authors, indexers, and users into a controlled vocabulary used for indexing and retrieval. • 一致性Consistency. 促进标引用词的一致性To promote consistency in the assignment of index terms. • 建立关系Indication of Relationships. 建立语词之间的语义联系To indicate semantic relationships among terms. • 检索Retrieval充当文献检索的辅助工具To serve as a searching aid in retrieval of documents. (ANSI Z39.19-1993, p. 1)

17. 词汇控制 信息控制和使用词根的需求来自于对自然语言两个缺点的克服: 多词一意Synonyms – different terms representing the same concept 一词多义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.]

18. 词汇控制（续） 叙词表的词汇控制通过三种方法达成：Vocabulary control in a thesaurus is achieved through three principal means: • 范围、含义说明the delineation of the scope, or meaning, of descriptors  Scope Note (SN)范围说明 • 同义词和近义词通过“等价关系”联系起来the linking of synonymous and nearly (quasi) synonymous terms through equivalence relationship  USE and UF • 通过修饰揭示同形异义情况the disambiguation of homographs  Qualifier (Source: ANSI Z39.19-1993, p. 1)

19. 结构和关系 • 叙词表必须能够揭示其所含叙词之间的结构关系An intrinsic feature of a thesaurus is its ability to distinguish and display the structural relationships between the terms it contains. • 叙词表内两类广义的关系There are two broad types of relationships within a thesaurus: • 微观层次——个体词之间的语义联系Micro Level – the semantic links between individual terms • 宏观层次——词和词间关系与主题领域的整体结构相关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)

20. 基本叙词关系 三类词间关系: • 等价: the relationship between preferred and non-preferred terms where two or more terms are regarded, for indexing purposes, as referring to the same concept • 层次: 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 • 相关: the relationship is found between terms which are closely related conceptually but not hierarchically and are not members of an equivalence set. (本頁及以下關于各種relationship的敘述，主要參考: Aitchison, Gilchrist, & Bawden, 1997, Section F)

21. 等价关系 • 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)

22. 等价关系（续） • 同义词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)

23. 等价关系（续） • 异形变体词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

24. 等价关系（续） • 近义词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

25. 等价关系（续） • 靠上位词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

26. 层次关系 互逆关系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 ……

27. 层次关系（续） • 一般/特殊关系Generic/species relationship– identifies the link between a class or category and its members or species (e.g., Bird / Robin) • 整体/部分关系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)

28. 层次关系（续） • 实例关系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) • 多对一层次关系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

29. 相关关系 • 关系是互逆的，由RT标示 • The relation is reciprocal, and is distinguished by the abbreviation “RT” (Related Terms) e.g., TEACING RT Teaching aids TEACHING AIDS RT Teaching

30. 相关关系（续） 有两种相关关系： • 同类相关Terms belonging to the same category (e.g., motorcycle / bicycle) • 异类相关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)

31. 相关关系（续） • 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)

32. 叙词表款目示例 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 ……

33. 显示 • 字顺Alphabetical • 分类Classified • 层次Hierarchical • 关键词索引Permuted Keyword Index • 图象表示Graphical

34. 序词表的设计 – 两步法 • 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

35. 叙词表的设计 – 信息系统因素 • 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)

36. 如何开发叙词表——自顶向下方法 • 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)

37. 如何开发叙词表——自底向上法 • 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)

38. 建立叙词表的步骤 • 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