More than Lists of Changes: Tracing the history of DDC concepts

More than Lists of Changes: Tracing the history of DDC concepts Dewey Breakfast/Update ALA Midwinter Meeting January 24, 2009

Overview • The why and how of representing change in knowledge organization systems • Parsing history information contained in the DDC • Providing access to history notes for machines and humans: a sneak peak at the history web service • Further plans

Change in knowledge organization systems • Tracking change • of the scheme as a whole (snapshots/editions) • of individual classes (contents of a classes) • of individual topics associated with a class

History information in concept schemes Lists of Changes available in the DDC Relocations Discontinuations Comparative and equivalence tables (not in Edition 22) Records of change not machine-actionable in a standard way Goal: Formally model change to make history of classes useful to Semantic Web agents and other discovery processes Change in knowledge organization systems

How to expose history information for machine access • Standard identifier (URL):<http://dewey.info/class/004.165/> • Type of history note:<http://dewey.info/class/004.165/> ddc:relocationNote [] • Normalized date:dcterms:issued "2008-08-01"^^xs:date • Relationships of note to scheme:dcterms:isPartOf <http://dewey.info/scheme/e22/> • Result of changedcterms:description "Partially changed number“@en

How to expose history information for machine access Numbers of affected classesddc:oldNumber "004.165"^^<schema-terms/Notation>ddc:newNumber "004.1675"^^<schema-terms/Notation> Affected topicddc:hasTopic "Specific handheld devices"@en Complete note in human-readable formrdf:value "Specific handheld devices relocated to 004.1675"@en

Class history as web service This data (as a service) should be able to answer exploratory questions: Were there any semantic changes to the class with the Dewey number 154.634 after May 2003? What is the (genetic) relationship between 157 and 616.89? Which classes in 940–949 have been completely vacated since the publication of Edition 22? What are the new numbers for these classes?

Why model change for access? Resolving mappings in retrieval components Mapping relationship: “BlackBerry”—“004.165” Timestamp of this mapping: 2007-02-04 Using history information 685 20 $tSpecific handheld devices $irelocated to $b004.1675 $d200808 $222 Expanded query: 004.165 [< 2007-02-03] 004.1675 [>= 2007-02-04] Additional information: 004.167 is a completely new number, so every mapping to 004.165 should automatically include 004.1675 until mappings are updated intellectually

Why model change for access? Verbal access to DDC for retrieval Search term: “Information theory” Resulting DDC number: 003.54 Using history information “Relocations and Discontinuations” (Ed. 20):Ed. 19: [001.539] Ed. 20: 003.54 685 01 $tInformation theory $iformerly located in $b001.539 $d19890306 $220 Expanded query: {001.539 20; 003.54 21; 003.54 22}

Further plans Make history data available as a free servicehttp://dewey.info/class/154.634/e22/history.en.rdf Much improved (more up-to-date & more readable) access also for human users to what has been Lists of Changes in the print edition At the same time: Test bed for a more comprehensive Dewey web service

Thank you! Any ideas how we could make DDC history information more helpful to you? panzerm@oclc.org

More than Lists of Changes: Tracing the history of DDC concepts