1 CS 502: Computing Methods for Digital Libraries Lecture 13 Descriptive Metadata I: cataloguing, classification, authority files

2 Administration Open laptop examination Read the Course Notices for instructions Remember, electronic communication is cheating! Extension of wireless network Uris Library and Olin Library (1st floor and basement) Schedule changes See Course Notices for next two lectures Change of dates for future assignments

3 Text Retrieval Conferences (TREC) Quantitative research in digital libraries. Compare performance of techniques, e.g., automatic thesauri, sophisticated term weighting, natural language techniques, relevance feedback, and advanced machine learning. Corpus of several million textual documents -- 5 Gbytes. Standard set of tasks, e.g., Search the corpus for topics provided Match a stream of documents against standard queries Participants include large commercial companies, small information retrieval vendors, and university research groups.

4 Descriptive metadata Catalog: metadata records that have a consistent structure, organized according to systematic rules. Abstract: a free text record that summarizes a longer document. Indexing record: less formal than a catalog record, but more structure than a simple abstract. Some methods of information discovery search descriptive metadata about the objects. Metadata typically consists of a catalog or indexing record, or an abstract, one record for each object.

5 Descriptive metadata Usually stored separately from the objects that it describes, but sometimes is embedded in the objects. Usually the metadata is a set of text fields. Textual metadata can be used to describe non-textual objects, e.g., software, images, music

6 Library Cataloguing Anglo American Cataloguing Rules (AACR2) rules for what goes into each field of a catalog record MARC format an exchange format for catalog records "MARC Catalog" catalog in MARC format, where content of each field follows AACR2

7 Example: Monograph catalog record Citation Caroline R. Arms, editor, Campus strategies for libraries and electronic information. Bedford, MA: Digital Press, 1990.

8 MARC fields tag value r Z675.U5C / Campus strategies for libraries and electronic title statement information/Caroline Arms, editor. 260 {Bedford, Mass.} : Digital Press, c1990. publisher 300 xi, 404 p. : ill. ; 24 cm. collation 440 EDUCOM strategies series on information technology series title 504 Includes bibliographical references (p. {373}-381). 020 ISBN X : $34.95

9 MARC fields (continued) 650 Academic libraries--United States--Automation. subject heading 650 Libraries and electronic publishing--United States. 650 Library information networks--United States. 650 Information technology--United States. 700 Arms, Caroline R. (Caroline Ruth) 040 DLC DLC DLC 043 n-us CIP ver. br02 to SL APIF/MIG

10 MARC Encoding tag: 260 subfield a:{Bedford, Mass.} : subfield b:Digital Press, subfield c:c1990. MARC encoding: &2600#abc#{Bedford, Mass.} :#Digital Press,#c1990.%

11 Name authority files Caroline R. Arms or Caroline Ruth Arms? Which William Phillips of Cardiff? Mark Twain or Samuel Clemens? Epithets: of Cardiff doctor Dates: flourished 1860 circa

12 Shared cataloguing OCLC -- Large centralized transaction processing database system When a library catalogs a book it deposits MARC record in OCLC Other libraries can copy the record saves duplication of cataloguing build database of holdings OCLC database has 42 million records

13 Subject information Library of Congress Subject Headings Academic libraries--United States--Automation Hierarchical classification Library of Congress call number:Z675.U5C16 Dewey Decimal Classification:027.7 Creation and maintenance of lists of subject headings and classifications is a never ending task.

14 Online public access catalog (OPAC) First stage Library mounts its MARC records on a central computer Provides a simple terminal interface and dedicated terminals Boolean search -- fielded searching [Most university libraries reached this stage about 1990] Second stage Library connects computer to a campus network and Internet Converts card catalog records to MARC (retrospective conversion)

15 Library information systems When the catalog is online... Add other collections and services: Secondary information (Inspec, Medline, Chemical Abstracts) Reference works (dictionaries, encyclopedias) Improve user interface Add full text searching Add web interface Add connections to off-campus information sources: Scientific journals Databases (census, genome)

16 Library management systems A library management system, sometimes called an integrated library system, integrates the internal processes of a library, e.g., acquisitions, cataloguing, binding, circulation, etc. It usually contains an online public access catalog, but does not provide integrated services to users. Library management systems are produced by small companies who lack the capital and technical expertise to develop modern digital libraries.

17 Notes on MARC A great achievement: Developed in 1960s Magnetic tape exchange format for printing catalog records The dawn of computing: mixed upper and lower case variable length fields, repeated fields non-Roman scripts 100(?) million records with standard content and format Thousands of trained librarians (millions?)

18 Notes on MARC A great problem: Not designed for computer algorithms One record per item (poor links between records) Tied to traditional materials and traditional practices Not Unicode 100 of million records at $ $10 billion A classic legacy system!