DCMI Kernel Metadata Task Group J. Kunze   A. Turner   California Digital Library   January 23, 2008 - DRAFT V1.3

Kernel Metadata/ERC and Dublin Core Application Profiles

 

Introduction

Kernel metadata ([KSPEC]) is a small prescriptive vocabulary designed to support highly uniform but minimal object descriptions for the purpose of orderly collection management. The Kernel vocabulary, based on a subset of the Dublin Core (DC) metadata element set, aims to describe objects of any form or category, but its reach is limited to a small number of fundamental questions such as who, what, when, and where. The Electronic Resource Citation (ERC) is a Kernel metadata-based profile, specifying requirements for representing Kernel metadata in any given object description.

This document comprises guidelines for representing Kernel metadata and ERC requirements, using Dublin Core Abstract Model [DCAM]-based application profiles.

Functional Requirements and Domain Model

Kernel metadata is designed to assist orderly collection management by supporting the creation of brief but highly uniform object descriptions that can be listed, surveyed, and searched efficiently during normal collection maintenance and trouble-shooting activities. These descriptions serve as object surrogates that are convenient for automated sorting and filtering operations and are also eye-readable without specialized display software. The goal of Kernel metadata is to balance the needs for expressive power, very simple machine processing, and direct human manipulation of metadata records.

Kernel metadata is based on the Dublin Core (DC) metadata element set [RFC5013] maintained by the Dublin Core Metadata Initiative [DCMI]. Kernel elements are descriptors that identify various object properties. In principle they apply to any object in the universe, whether digital, physical, or abstract, following in the tradition of [RFC3986]. This extreme diversity of objects is approached with the hypothesis that highly variable and rich object descriptions can be directly comparable at the level of about four fundamental elements — who, what, when, and where — as applied to the expression (i.e., publication, installation, performance, discovery) of the object. This sequence is a recurring theme in the Kernel. In anticipation of future extensions to "how" and "why", we refer to the first four elements as "the four h's" (what they all have in common is an initial aspirated "h" sound, which is also shorter to say than "w").

Kernel-based descriptions make it possible to compare an extremely diverse set of objects. Comparison is possible even when many other elements co-exist with Kernel elements, or when a minor amount of information in other elements overlaps with Kernel element information. Regardless of whether an object is smoked, worn, navigated, or in any other way, interacted with, its Kernel based description ensures the presence of a few predictable points of commonality in the form of easily isolatable Kernel elements. Kernel elements provide a concise intersection of interoperable (or at least comparable) elements across a broad range of object descriptions.

Syntax and Usage Guidelines

Standard encoding methods such as [RDF] and [XML] may be used to format ERCs and Kernel metadata. It is also possible to encode modified forms of Kernel element values using other methods, such as [MARC] or [MODS], although some granularity of information may be lost in the process. For specific syntax and usage guidelines, refer to the Kernel metadata specification [KSPEC] and crosswalk to other encoding schemes [KMAP].

Description Set Profile

ERC requirements can be roughly mapped to Dublin Core Abstract Model [DCAM]-based application profiles -- such as the Simple Dublin Core application profile [SIMPLEDC] -- as outlined in the tables below (with some modifications to accommodate mappings to a few qualified Dublin Core elements). In principle, however, ERC requirements may be expressed through any formal Dublin Core application profile (such as for EPrints [EPRINTS] or Dublin Core Collections [DCCOLL]), with the following conditions:

• All four Kernel elements "who", "what", "when", and "where" must be present with no missing values; these four h's each have the coded synonyms h1, h2, h3, and h4, respectively. These four Kernel elements roughly correspond to Dublin Core elements, as described in the table below. If a best effort to supply a value fails, in its place must be given a standardized value based on the Kernel specification [KSPEC] indicating the reason for the missing value.

KERNEL ELEMENT  SYNONYM			DUBLIN CORE ELEMENT APPROXIMATION

*  who          h1			Creator/Contributor/Publisher
*  what         h2			Title
*  when         h3			Date
*  where        h4			Identifier (permanent)

about-who      	h11			Subject (personage)
about-what     	h12			Subject
about-when     	h13			Coverage (temporal)
about-where    	h14			Coverage (spatial)
about-how      	h15			Description


*  A complete record requires a non-missing value for this element.

• Some Kernel elements should contain values formatted in a particular manner. This formatting should carry over into any representation of the values in Dublin Core elements.
  • The Kernel assumes that most values, especially personal names given in "who", will be given in "sort-friendly" manner, for example, "lastname, firstname" for western names and natural word order for Chinese names.
  • The Kernel assumes [TEMPER] format for dates in order to express date ranges, lists, approximate dates, and BC dates (not possible, for example, with [W3CDTF].

 

Creator

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Title

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Date

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Identifier

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Subject (Personage)

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Subject

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Coverage (Temporal)

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Coverage (Spatial)

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Description

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Publisher

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Contributor

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References

[AACR2]	American Library Association, “Anglo-American Cataloguing Rules,” 2007 (HTML).
[DCAM]	Powell A. and M. Nilsson et al., “DCMI Abstract Model”, June 2007 (HTML).
[DCCOLL]	Dublin Core Collection Description Task Group, “Dublin Core Collections Application Profile”, March 2007 (HTML).
[DCMI]	Dublin Core Metadata Initiative, “DCMI Metadata Terms”, December 2006 (HTML).
[EPRINTS]	Allinson, J. and A. Powell, “EPrints Application Profile”, 2007 (HTML).
[KMAP]	Kunze, J. and A. Turner, “Mapping and Crosswalk: Kernel Metadata to Dublin Core, MARC21, MODS, and VRA Core”, September 2007 (HTML).
[KSPEC]	Kunze, J. and A. Turner, “Kernel Metadata and Electronic Resource Citations (ERCs)”, October 2007 (HTML).
[MARC]	Library of Congress, “Machine Readable Cataloguing,” 2007 (HTML).
[MODS]	Library of Congress, “Metadata Object Description Schema,” June 2006 (HTML).
[RDF]	W3C, “Resource Description Framework”, 2004 (HTML).
[SIMPLEDC]	Enoksson, F., “Simple Dublin Core: an Application Profile,” September 2007 (HTML).
[TEMPER]	Blair, C. and J. Kunze, “Temporal Enumerated Ranges,” August 2007 (PDF).
[W3CDTF]	W3C, “Date and Time Formats (W3C profile of ISO8601)”, September 1997 (HTML).
[XML]	W3C, “Extensible Markup Language (XML) 1.0 (Fourth Edition),” August 2006 (HTML).
[RFC5013]	Kunze, J. and T. Baker, “The Dublin Core Metadata Element Set,” RFC 5013, August 2007 (HTML).
[RFC3986]	Berners-Lee, T., Fielding, R., and L. Masinter, “Uniform Resource Identifier (URI): Generic Syntax,” STD 66, RFC 3986, January 2005 (TXT, HTML, XML).