CS 430: Information Discovery Lecture 7 Descriptive Metadata 3 Dublin Core Automatic Generation of Catalog Records 1 Course Administration • 2 Relationship between Library of Congress, OCLC and American Memory Dublin Core elements 1. Title The name given to the resource by the creator or publisher. 2. Creator The person or organization primarily responsible for the intellectual content of the resource. For example, authors in the case of written documents, artists, photographers, or illustrators in the case of visual resources. 3. Subject The topic of the resource. Typically, subject will be expressed as keywords or phrases that describe the subject or content of the resource. The use of controlled vocabularies and formal classification schemes is encouraged. 3 Dublin Core elements 4. Description A textual description of the content of the resource, including abstracts in the case of document-like objects or content descriptions in the case of visual resources. 5. Publisher The entity responsible for making the resource available in its present form, such as a publishing house, a university department, or a corporate entity. 6. Contributor A person or organization not specified in a creator element who has made significant intellectual contributions to the resource but whose contribution is secondary to any person or organization specified in a creator element (for example, editor, transcriber, and illustrator). 4 Dublin Core elements 7. Date A date associated with the creation or availability of the resource. 8. Type The category of the resource, such as home page, novel, poem, working paper, preprint, technical report, essay, dictionary. 9. Format The data format of the resource, used to identify the software and possibly hardware that might be needed to display or operate the resource. 5 10. Identifier A string or number used to uniquely identify the resource. Examples for networked resources include URLs and URNs. Dublin Core elements 11. Source Information about a second resource from which the present resource is derived. 12. Language The language of the intellectual content of the resource. 13. Relation An identifier of a second resource and its relationship to the present resource. This element permits links between related resources and resource descriptions to be indicated. Examples include an edition of a work (IsVersionOf), or a chapter of a book (IsPartOf). 6 Dublin Core elements 14. Coverage The spatial locations and temporal durations characteristic of the resource. 15. Rights A rights management statement, an identifier that links to a rights management statement, or an identifier that links to a service providing information about rights management for the resource. 7 Qualifiers Element qualifier Example: Date DC.Date -> Created: 1997-11-01 DC.Date -> Issued: 1997-11-15 DC.Date -> Available: 1997-12-01/1998-06-01 DC.Date -> Valid: 1998-01-01/1998-06-01 8 Qualifiers Value qualifiers Example: Subject DC.Subject -> DDC: 509.123 DC.Subject -> LCSH: Digital libraries-United States 9 Metadata about subjects (a) Classification (usually manual) Dewey Decimal Classification (DDC) 324.973 political web site Library of Congress classification system (LCC) E840.8.G65 political web site (b) Subject headings (usually manual) Keywords assigned from controlled vocabulary e.g., Medical Subject Headings (MeSH) Library of Congress subject headings (LCSH) Political campaigns - United States (c) Terms extracted from text (automatic) 10 Automatic indexing [CS 430] Methods from computational linguistics [CS 374/474] Dewey Decimal Classification Main classes: 000 Computers, information, & general reference 100 Philosophy & psychology 200 Religion 300 Social sciences 400 Language 500 Science 600 Technology 700 Arts & recreation 800 Literature 900 History & geography 11 Dewey Decimal Classification Hierarchy, e.g.: 600 Technology (Applied sciences) 630 Agriculture and related technologies 636 Animal husbandry 636.7 Dogs 636.8 Cats Uses: • Shelving collections of physical objects so that items on similar subjects are shelved together • Crude subject access Scorpion project (OCLC): Automatic subject recognition and assignment of DDC classes 12 13 14 Limits of Dublin Core Complex objects Metadata records Complete object Sub-objects • Article within a journal • A thumbnail of another image • The March 28 final edition of a newspaper 15 Flat v. linked records Flat record All information about an item is held in a single Dublin Core record, including information about related items convenient for access and preservation information is repeated -- maintenance problem Linked record Related information is held in separate records with a link from the item record less convenient for access and preservation information is stored once Compare with normal forms in relational databases 16 17 Dublin Core with qualifiers <title>Digital Libraries and the Problem of Purpose</title> <creator>David M. Levy</creator> <publisher>Corporation for National Research Initiatives</publisher> <date date-type = "publication">January 2000</date> <type resource-type = "work">article</type> <identifier uri-type = "DOI">10.1045/january2000-levy</identifier> <identifier uri-type = "URL">http://www.dlib.org/dlib/january00/01levy.html</identifier> <language>English</language> <rights>Copyright (c) David M. Levy</rights> 18 Dublin Core with flat record extension Continuation <relation rel-type = "InSerial"> <serial-name>D-Lib Magazine</serial-name> <issn>1082-9873</issn> <volume>6</volume> <issue>1</issue> </relation> 19 Events Version 1 Version 2 New material Should Version 2 have its own record or should extra information be added to the Version 2 record? How are these represented in Dublin Core? 20 Minimalist versus structuralist Minimalist 15 elements, no qualifiers, suitable for non-professionals encourage creators to provide metadata Structuralists 15 elements, qualifiers, RDF, detailed coding rules will require trained metadata experts [For an example of how complex Dublin Core can become, see the source of: http://purl.org/dc/documents/rec-dces199809.htm#] 21 Dublin Core in many languages See: Thomas Baker, Languages for Dublin Core, D-Lib Magazine December 1998, http://www.dlib.org/dlib/december98/12baker.html 22 Dublin Core: Personal Opinion Dublin Core is a simple way to describe digital content that: • is a single, self-contained object ("document-like") • is static with time • has few relationships Some web sites satisfy these criteria Dublin Core is not suitable for digital content that: • is heavily structured • changes dynamically 23 Automatic extraction of catalog data Example: Dublin Core records for web pages Strategies 24 • Manual by trained cataloguers - high quality records, but expensive and time consuming • Entirely automatic - fast, almost zero cost, but poor quality • Automatic followed by human editing - cost and quality depend on the amount of editing • Manual collection level record, automatic item level record - moderate quality, moderate cost DC-dot DC-dot is a Dublin Core metadata editor for web pages, created by Andy Powell at UKOLN http://www.ukoln.ac.uk/metadata/dcdot/ DC-dot has two parts: (a) A skeleton Dublin Core record is created automatically from clues in the web page (b) A user interface is provided for cataloguers to edit the record 25 26 Automatic record for CS 430 home page DC-dot applied to http://www.cs.cornell.edu/courses/cs430/2001sp/ <link rel="schema.DC" href="http://purl.org/dc"> <meta name="DC.Title" content="CS 430: Information Discovery"> <meta name="DC.Subject" content="wya@cs.cornell.edu; Course Structure; Readings and references; Slides; Basic Information; William Y. Arms; Information Retrieval Data Structures and Algorithms; cs430@cs.cornell.edu; Assignments; Syllabus; Text Book; Laptop computers; Assumed Background; Nomadic Computing Experiment; Notices; Course Description; Code of practice; Assignments and Grading; Last changed: February 6, 2001"> continued on next slide 27 Automatic record for CS 430 home page (continued) DC-dot applied to http://www.cs.cornell.edu/courses/cs430/2001sp/ <meta name="DC.Publisher" content="Cornell University"> <meta name="DC.Date" scheme="W3CDTF" content="2001-02-07"> <meta name="DC.Type" scheme="DCMIType" content="Text"> <meta name="DC.Format" content="text/html"> <meta name="DC.Format" content="5781 bytes"> <meta name="DC.Identifier" content="http://www.cs.cornell.edu/courses/cs430/2001sp/"> 28 Observations on DC-dot applied to CS430 home page DC.Title is a copy of the html <title> field DC.Publisher is the owner of the IP address where the page was stored DC.Subject is a list of headings and noun phrases presented for editing DC.Date is taken from the Last-Modified field in the http header DC.Type and DC.Format are taken from the MIME type of the http response DC.Identifier was supplied by the user as input 29 30 Automatic record for George W. Bush home page DC-dot applied to http://www.georgewbush.com/ <link rel="schema.DC" href="http://purl.org/dc"> <meta name="DC.Subject" content="George W. Bush; Bush; George Bush; President; republican; 2000 election; election; presidential election; George; B2K; Bush for President; Junior; Texas; Governor; taxes; technology; education; agriculture; health care; environment; society; social security; medicare; income tax; foreign policy; defense; government"> <meta name="DC.Description" content="George W. Bush is running for President of the United States to keep the country prosperous."> 31 continued on next slide Automatic record for George W. Bush home page (continued) DC-dot applied to http://www.georgewbush.com/ <meta name="DC.Publisher" content="Concentric Network Corporation"> <meta name="DC.Date" scheme="W3CDTF" content="2001-01-12"> <meta name="DC.Type" scheme="DCMIType" content="Text"> <meta name="DC.Format" content="text/html"> <meta name="DC.Format" content="12223 bytes"> <meta name="DC.Identifier" content="http://www.georgewbush.com/"> 32 Observations on DC-dot applied to George W. Bush home page The home page has several meta tags: <META NAME="TITLE" CONTENT="George W. Bush for President"> [The page has no html <title>] <META NAME="CONTACT" CONTENT="George W Bush Campaign, P. O. Box 1902, Austin, TX 78767, Phone: (512) 6372000"> <META NAME="DESCRIPTION" CONTENT="George W. Bush is running for President of the United States to keep the country prosperous."> <META NAME="KEYWORDS" CONTENT="George W. Bush, Bush, George Bush, President, republican, 2000 election and more 33 Collection-level metadata Several of the most difficult fields to extract automatically are the same across all pages in a web site. Therefore create a collection record manually and combine it with automatic extraction of other fields at item level. For the CS 430 home page, collection-level metadata: <meta name="DC.Publisher" content="Cornell University"> <meta name="DC.Creator" content="William Y. Arms"> <meta name="DC.Rights" content="William Y. Arms, 2001"> See: Jenkins and Inman 34 Collection-level metadata Compare: (a) Metadata extracted automatically by DC-dot (b) Collection-level record (c) Combined item-level record (DC-dot plus collection-level) (d) Manual record 35 36 Metadata extracted automatically by DC-dot D.C. Field Qualifier Content title Digital Libraries and the Problem of Purpose subject not included in this slide publisher Corporation for National Research Initiatives date W3CDTF 2000-05-11 type DCMIType Text format text/html format 27718 bytes 37 identifier http://www.dlib.org/dlib/january00/01levy.html Collection-level record D.C. Field Qualifier Content publisher Corporation for National Research Initiatives type article type resource work relation rel-type InSerial relation serial-name D-Lib Magazine relation issn 1082-9873 language English rights Permission is hereby given for the material in D-Lib Magazine to be used for ... 38 Combined item-level record (DC-dot plus collection-level) D.C. Field Qualifier Content title publisher date type Digital Libraries and the Problem of Purpose (*) Corporation for National Research Initiatives W3CDTF 2000-05-11 (*) article type type format resource (*) work DCMIType Text text/html format 27718 bytes (*) indicates collection-level metadata continued on next slide 39 Combined item-level record (DC-dot plus collection-level) D.C. Field Qualifier Content relation rel-type (*) InSerial relation serial-name (*) D-Lib Magazine relation issn (*) 1082-9873 language (*) English rights (*) Permission is hereby given for the material in D-Lib Magazine to be used for ... identifier http://www.dlib.org/dlib/january00/01levy.html (*) indicates collection-level metadata 40 Manually created record D.C. Field Qualifier title Digital Libraries and the Problem of Purpose creator (+) David M. Levy publisher date type type Content Corporation for National Research Initiatives publication resource January 2000 article work (+) entry that is not in the automatically generated records continued on next slide 41 Manually created record D.C. Field Qualifier relation relation relation relation relation identifier identifier language rights Content rel-type InSerial serial-name D-Lib Magazine issn 1082-9873 volume (+) 6 issue (+) 1 DOI (+) 10.1045/january2000-levy URL http://www.dlib.org/dlib/january00/01levy.html English (+) Copyright (c) David M. Levy (+) entry that is not in the automatically generated records 42