Docstoc

Interoperability_ OAI_ and Metadata

Document Sample
Interoperability_ OAI_ and Metadata Powered By Docstoc
					Search Interoperability, OAI, and Metadata
Sarah Shreeves University of Illinois at Urbana-Champaign

Basics and Beyond Grainger Engineering Library April 18, 2005

Scenario:
A teacher is putting together a lesson plan comparing immigration in the early 20th century to immigration and wants to include a variety of primary sources

April 18, 2005

Basics and Beyond Grainger Engineering Library

IMLS funded digital collections with relevant content

April 18, 2005

Basics and Beyond Grainger Engineering Library

Search interoperability
“the ability to perform a search over diverse sets of metadata records and obtain meaningful results.”
– Priscilla Caplan Metadata Fundamentals for All Librarians

April 18, 2005

Basics and Beyond Grainger Engineering Library

Keys to Search Interoperability
    

Communication protocol (Z39.50, OAI, etc.) Organizational commitment Standards Standards And More Standards

April 18, 2005

Basics and Beyond Grainger Engineering Library

Sharing metadata : Federated search
The distributed databases are searched directly.
<title>My resource< /title> <date>04

Mill?

<title>My resource< /title> <date>04

<title>My resource< /title> <date>04

For Example:
Z39.50, SRU/SRW
Basics and Beyond Grainger Engineering Library

April 18, 2005

Sharing metadata : Data aggregation
The user searches a pre-aggregated database of metadata from diverse sources.
Mill?
<title>My resource< /title> <date>04

For Example: Search engines, union catalogs, OAI
April 18, 2005 Basics and Beyond Grainger Engineering Library

Open Archives Initiative Protocol for Metadata Harvesting
The OAI-PMH is a tool


Moves metadata (not content for the most part yet) from a data provider to a service provider (or harvester) A set of rules that defines the communication between two systems (like FTP and HTTP)



Facilitates the aggregation of metadata (like a union catalog)

April 18, 2005

Basics and Beyond Grainger Engineering Library

Basic OAI-PMH Concepts
 

“Aggregated search” rather than “Federated search” Data providers – support OAI PMH as a means to expose metadata Service providers – „harvests‟ metadata from data providers via the OAI-PMH OAI-PMH based upon HTTP and XML OAI-PMH requires use of simple Dublin Core
BUT supports and encourages use of other metadata schemas



 



Unique and Persistent Identifiers and a Datestamp for each OAI record

April 18, 2005

Basics and Beyond Grainger Engineering Library

OAIster: http://www.oaister.org/o/oaister/ CIC Metadata Portal: http://nergal.grainger.uiuc.edu/cgi/b/bib/oaister

April 18, 2005

Basics and Beyond Grainger Engineering Library

How OAI Works (Technically)
Service Provider Data Provider



6 distinct „verbs‟ or requests
OAI requests are sent via HTTP Responses are sent in valid XML
April 18, 2005





A G G R E G A T E D

OAI
M E T A D A T A H A R V E S T E R

OAI HTTP Request Data P Dig. (OAI Verb) R O Mngt. V HTTP Response I Sys. (Valid XML) D E R

Basics and Beyond Grainger Engineering Library

Examples of OAI Service Providers


OAIster: http://oaister.umdl.umich.edu/o/oaister/ Engineering, Computer Science, and Physics: http://g118.grainger.uiuc.edu/engroai/ Open Language Archives Community: http://www.language-archives.org/
Basics and Beyond Grainger Engineering Library





April 18, 2005

OAI “VERBS”
Identify ListMetadataFormats

ListSets
ListIdentifiers GetRecord ListRecords

April 18, 2005

Basics and Beyond Grainger Engineering Library

Challenges for the OAI Community
 

No best practices (yet) „Shareablity of metadata‟
  

Heterogeneity of items described Loss of Context / Information loss Knowledge structures differ so….





Native metadata schemas differ Controlled vocabularies differ Use and presentation of items differ

April 18, 2005

Basics and Beyond Grainger Engineering Library

OAI ≠ Dublin Core
DC is OAI‟s lowest common denominator

BUT
OAI supports & encourages use of other community-driven metadata schemas
April 18, 2005 Basics and Beyond Grainger Engineering Library

Metadata Interoperability


Semantics
 

What is the metadata format used? Mapping from one format to another How are values for the metadata elements selected and represented? How are the metadata elements encoded in machine readable form?



Content rules




Syntax




Documentation
Basics and Beyond Grainger Engineering Library

April 18, 2005

April 18, 2005

Basics and Beyond Grainger Engineering Library

Metadata for different communities

April 18, 2005

Basics and Beyond Grainger Engineering Library

Metadata for different communities

April 18, 2005

Basics and Beyond Grainger Engineering Library

Loss of Context: Record in OAI aggregation

April 18, 2005

Basics and Beyond Grainger Engineering Library

Context: Record in native database

April 18, 2005

Basics and Beyond Grainger Engineering Library

Loss of context / data

April 18, 2005

Basics and Beyond Grainger Engineering Library

Loss of context / data

April 18, 2005

Basics and Beyond Grainger Engineering Library

Granularity of Description: Excerpt of Metadata Record Describing “American Woven Coverlet”

April 18, 2005

Basics and Beyond Grainger Engineering Library

Granularity of Description: Excerpt of Metadata Record Describing "Cotton coverlet with embroidered butterfly design"

April 18, 2005

Basics and Beyond Grainger Engineering Library

What does this record represent?


   

 

identifier:http://images.umdl.umich.edu/cgi/i/image/imageidx?view=entry;subview=detail;cc=fish3ic;entryid=X0802;viewid=1004_112 publisher: UMMZ Fish Division format: jpeg type: image subject: 1926-05-18;1926;0812;18;Trib. to Sixteen Cr. Trib. Pine River, Manistee R.;R10W;S26; S27;JAM26460;05;T21N;1926/05/18 language: UND description: Flora and Fauna of the Great Lakes Region;
Basics and Beyond Grainger Engineering Library

April 18, 2005

April 18, 2005

Basics and Beyond Grainger Engineering Library

Data providers can:


Create metadata for interoperability


Reusable metadata - think beyond your local users and environment Use well structured and defined schemas; move beyond simple DC Use and identify controlled vocabularies Document, document, document
Basics and Beyond Grainger Engineering Library







April 18, 2005

Service Providers can…


Analyze metadata and cluster and normalize some aspects Provide contextual information (such as collection descriptions)





Custom interfaces and selective views for target audiences / domains

April 18, 2005

Basics and Beyond Grainger Engineering Library

Contact Information
Sarah Shreeves Project Coordinator, IMLS Digital Collections and Content Project University of Illinois at Urbana-Champaign sshreeve@uiuc.edu 217-244-7809 Presentation available:
http://imlsdcc.grainger.uiuc.edu/basicsbeyondMar2005.ppt
April 18, 2005 Basics and Beyond Grainger Engineering Library


				
DOCUMENT INFO