Metadata Standards in Various EnvironmentsMetadata Standards in Various Environments

Spring 2006Spring 200630 January, 200630 January, 2006

Bharat MehraBharat MehraIS 520 Organization and Representation of Information IS 520 Organization and Representation of Information

School of Information SciencesSchool of Information SciencesUniversity of TennesseeUniversity of Tennessee

What is Metadata? What is Metadata? Structured information that describes, explains, locates,

or makes it easier to retrieve, use, or manage an information resource (information object?)

Data about data or information about information

Used differently in different communities “machine understandable information”; library environment: any formal scheme of resource (information object) description

Why Metadata?Why Metadata?

Why Metadata?Why Metadata?

Why Why Metadata?Metadata?

Why Metadata?Why Metadata?

Types of Metadata SchemesTypes of Metadata Schemes Descriptive metadata describes a resource for purposes such as

discovery and identification (title, abstract, author, and keywords)

Structural metadata indicates how compound objects are put together (how pages are ordered to form chapters)

Administrative metadata provides information to help manage a resource (when and how it was created, file type and other technical information, and who can access it)

Rights management metadata, which deals with intellectual property rights

Preservation metadata, which contains information needed to archive and preserve a resource

Characteristics of MetadataCharacteristics of MetadataScale of Metadata can describe resources at any level of

aggregation

Metadata can be for work, expression, manifestation, or item

Metadata can be embedded in a digital object or it can be stored separately

QUESTIONMetadata is often embedded in HTML documents and in the headers of image files. Advantages and disadvantages?

Functions of MetadataFunctions of Metadata• Facilitates discovery of relevant information (resource

discovery)

• Organizes electronic resources

• Facilitates interoperability and legacy resource integration

• Provide digital identification, and support archiving and preservation

Resource Discovery¶ allowing resources to be found by relevant criteria;¶ identifying resources¶ bringing similar resources together¶ distinguishing dissimilar resources¶ giving location information

Functions of MetadataFunctions of MetadataOrganizing Electronic Resources¶ Aggregate sites or portals organizing links to resources based on

audience or topic ¶ Built as static webpages, with the names and locations of the resources

“hardcoded” in HTML¶ Build pages dynamically from metadata stored in databases: extraction

tools

InteroperabilityAllows information object to be understood by both humans and machines in ways that promote interoperability

Functions of MetadataFunctions of MetadataInteroperability

ability of multiple systems with different hardware and software platforms, data structures, and interfaces to exchange data with minimal loss of content and functionality

Two approaches to interoperability

a) Cross-system search and metadata harvesting Z39.50 protocol does not share metadata but maps own search capabilities to a common set of search attributes

b) Open Archives Initiative translate their native metadata to a common core set of elements and expose this for harvesting. A search service provider gathers the metadata into a consistent central index to allow cross-repository searching regardless of the metadata formats used

Functions of MetadataFunctions of MetadataDigital Identification¶ Most metadata schemes include elements (standard numbers) to uniquely identify the info object to which the metadata refers

¶ Location of a info object may also be given using a file name, URL (Uniform Resource Locator), or some more persistent identifier such as a PURL (Persistent URL) or DOI (Digital Object Identifier)

Archiving and Preservation: digital resources will not survive in usable form into the future. Why?

Metadata is key to ensuring that resources will survive and continue to be accessible into the future. Archiving and preservation require special elements to track the lineage of a digital object (where it came from and how it has changed over time), to detail its physical characteristics, and to document its behavior in order to emulate it

Metadata: Vocabulary Metadata: Vocabulary Metadata framework: sets of metadata elements designed for a specific purpose, such as describing a particular type of information resource

Semantics of scheme: definition or meaning of the elements themselves

Content: values given to metadata elements

Metadata schemes: specify names of elements, their semantics, and content rules for how content must be formulated (for example, how to identify the main title), representation rules for content (for example, capitalization rules), and allowable content values (for example, terms must be used from a specified controlled vocabulary)

Syntax rules: how the elements and their content should be encoded. A metadata scheme with no prescribed syntax rules is called syntax independent

Metadata: Vocabulary Metadata: Vocabulary Metadata Framework: Metadata Framework: Define what information is needed as metadata. Metadata content from any one framework can be encoded in many different formats

Encoding in definable syntax: e.g., SGML (Standard Generalized Mark-up Language) or XML (Extensible Mark-up Language).

XML is an extended form of HTML that allows for locally defined tag sets and the easy exchange of structured information. SGML is a superset of both HTML and XML and allows for the richest mark-up of a document.

Metadata Encoding: Metadata Encoding: A syntactic scheme for writing down some metadata content.

A specification of the kinds of info that should be presented to describe an info object

Mark-up language: Mark-up language: Metadata encoded and actually embedded within a document using a specific syntactic (and semantic) scheme

Metadata SchemesMetadata Schemes

Qualified and unqualified (or simple) Dublin Core. Qualifiers can be used to refine (narrow the scope of) an element, or to identify the encoding scheme used in representingan element value. The element Date, for example, can be used with the refinement qualifier created to narrow the meaning of the element to the date the object wascreated.

Title, Creator, Subject, Description, Publisher, Contributor, Date, Type, Format, Identifier, Source, Language, Relation, Coverage, and Rights.

Metadata SchemeMetadata SchemeDublin Core Dublin Core from a 1995 workshop sponsored by OCLC and the National Center for Supercomputing Applications

Title=”Metadata Demystified”Creator=”Brand, Amy”Creator=”Daly, Frank”Creator=”Meyers, Barbara”Subject=”metadata”Description=”Presents an overview ofmetadata conventions inpublishing.”Publisher=”NISO Press”Publisher=”The Sheridan Press”Date=”2003-07"Type=”Text”Format=”application/pdf”Identifier=”http://www.niso.org/standards/resources/Metadata_Demystified.pdf”Language=”en”

The Text Encoding Initiative (TEI)

¶ International project to develop guidelines for marking up electronic texts such as novels, plays, and poetry, primarily to support research in the humanities

¶ Specifies how to: encode the text of a work, header portion, embedded resource (contains metadata about the work)

¶ TEI header, like the rest of the TEI, is defined as an SGML DTD (Document Type Definition)—a set of tags and rules defined in

SGML syntax that describe the structure and elements of a document. This SGML mark-up becomes part of the electronic resource itself

Metadata SchemesMetadata Schemes

Metadata Encoding and Transmission Standard (METS)

¶ Provides a standard data structure for describing complex digital library objects

¶ METS is an XML Schema for creating XML documentinstances that express the structure of digital library objects, the associated descriptive and administrative metadata, and the names and locations of the files that comprise the digital object

Metadata SchemesMetadata Schemes

Metadata SchemesMetadata SchemesMetadata Object Description Schema (MODS)

¶ Descriptive metadata schema that is a derivative of MARC 21 and intended to either carry selecteddata from existing MARC 21 records or enable the creation of original resource description records

¶ Includes a subset of MARC fields and uses language based tags rather than the numeric

ones used in MARC 21 records. In some cases, it regroups elements from the MARC 21 bibliographicformat

¶ Like METS, MODS is expressed using the XML schema language

Metadata SchemesMetadata SchemesA MODS Record Example<mods><titleInfo><title>Metadata demystified</title></titleInfo><name type=”personal”><namePart type=”family”>Brand</namePart><namePart type=”given”>Amy</namePart><role><roleTerm authority=”marcrelator” type=”text”>author</roleTerm></role></name><typeOfResource>text</typeOfResource><originInfo><dateIssued>2003</dateIssued><place><placeTerm type=”text”>Bethesda, MD</placeTerm></place><publisher>NISO Press</publisher></originInfo><identifier type=”isbn”>1-880124-59-9</identifier></mods>

Metadata Schemes Metadata Schemes

Learning Object Metadata¶ Developed by the Learning Technology Standards Committee

(LTSC) to enable the use and re-use of technology-supported learning resources such as computer-based training and distance learning

¶ LOM defines the minimal set of attributes to manage, locate, and evaluate learning objects that include:

•General, containing information about the object as a whole

• Lifecycle, containing metadata about the objects evolution

• Technical, with descriptions of the technical characteristics and

requirements

• Educational, containing the educational

Metadata Schemes Metadata Schemes The Encoded Archival Description (EAD)Used for marking up the data contained in finding aids so that they can be searched and displayed online for archive and special collections

E-Commerce – <indecs> and ONIXDeveloped to support electronic commerce applications. <indecs> Framework (Interoperability of Data in ECommerce Systems) and ONIX (Online Information Exchange): XML-based scheme developed by publishers in the book industry

Visual Objects – CDWA and VRACategories for Descriptors for Works of Art Visual Resource Association

MPEG Multimedia MetadataMoving Pictures Expert Group

Metadata for DatasetsFederal Geographic Data Committee (FGDC) Content Standard for Digital Geospatial Metadata

Sample Metadata Encoding: Dublin Core in HTMLSample Metadata Encoding: Dublin Core in HTML

<META NAME=“DC.Title” Content=“IS 520 Syllabus <META NAME=“DC.Title” Content=“IS 520 Syllabus Page”>Page”>

<META NAME=“DC.Creator” Content=“Bharat <META NAME=“DC.Creator” Content=“Bharat Mehra”>Mehra”>

<META NAME=“DC.Creator.Address” <META NAME=“DC.Creator.Address” Content=bmehra@utk.edu>>

<META NAME=“DC.Subject” <META NAME=“DC.Subject” Content=“Information Organization and Content=“Information Organization and Representation”>Representation”>

Sample Metadata Encoding: Dublin Core in XMLSample Metadata Encoding: Dublin Core in XML<?xml version=“1.0”?><?xml version=“1.0”?><dc:title>IS 520 Syllabus <dc:title>IS 520 Syllabus Page</dc:title>Page</dc:title><dc:creator>Bharat Mehra</dc:creator><dc:creator>Bharat Mehra</dc:creator><dc:subject>Information Organization <dc:subject>Information Organization and Representation</dc:subject>and Representation</dc:subject>

<dc:subject>IS 520</dc:subject><dc:subject>IS 520</dc:subject><dc:date>2005-09-13</dc:date><dc:date>2005-09-13</dc:date><dc:format>text/html</dc:format><dc:format>text/html</dc:format><dc:language>en</dc:language><dc:language>en</dc:language>

Comparison: same content but different encoding Comparison: same content but different encoding

HTML: HTML: <META NAME=“DC.Creator” Content=“Bharat Mehra”>

XML:XML: <dc:creator>Bharat Mehra</dc:creator>

Metadata Encoding: Interoperability & Exchange Metadata Encoding: Interoperability & Exchange

The Resource D e s c r i p t i o n Framework (RDF), developed by the World Wide Web Consortium (W3C), is a data model for the description of resources on the Web that provides a mechanism for integrating multiple metadata schemes

Metadata Cross-walks: that help to map the elements, semantics, and syntax from one metadata scheme to those of another

Metadata Registries: Provide information about definition, origin, source, and location of data

Extensions and Profiles: Modifications to metadata schemes

An extension is the addition of elements to an already developed scheme to support the description of an information resource of a particular type or subject or to meet the needs of a particular interest group

Profiles are subsets of a scheme that are implemented by a particular interest group

Creation Tools: Templates, Mark-up tools, Extraction tools, Conversion tools

Metadata Quality Control Metadata Quality Control

Framework of Guidance for Building Good Digital Collections Articulates six principles applying to good metadata:

• Appropriate to the materials in the collection, users of the collection, and intended, current and likely use of the digital object

• Supports interoperability

• Uses standard controlled vocabularies to reflect the what, where, when and who of the content

• Includes a clear statement on the conditions and terms of use for the digital object

• Records are objects themselves and therefore should have the qualities of archiving, persistence, unique identification

• Authoritative and verifiable

• Supports the long-term management of objects in collections

““Critical Reflection Assignment 3”Critical Reflection Assignment 3”

Each group will be given an “information object” and the group Each group will be given an “information object” and the group task is to create a bibliographic card of eight fields. Each group task is to create a bibliographic card of eight fields. Each group has to choose the eight fields according to their perception of has to choose the eight fields according to their perception of the importance of those fields in searching for that particular the importance of those fields in searching for that particular item and rank the fields in the order of importance. Identify what item and rank the fields in the order of importance. Identify what you did and what you learned from the process. What thoughts you did and what you learned from the process. What thoughts did you have before, during or after the exercise? What did the did you have before, during or after the exercise? What did the process help you understand about the process of organization process help you understand about the process of organization and representation of information?and representation of information?