Open for Business - Open Archives, OpenURL, RSS and the Dublin Core

UKOLN is supported by:

Open for Business

Open Archives, OpenURL, RSS and the Dublin Core

Andy Powell, UKOLN, University of Bath

[email protected]

UKSG 2004, Manchester

www.bath.ac.uk

a centre of expertise in digital information management

www.ukoln.ac.uk

UKSG 2004, Manchester 2

Contents

• context – metasearching and open ‘context sensitive’ linking

• bluffer’s guides to…– Dublin Core– OAI Protocol for Metadata Harvesting– RSS– OpenURL

• discussion about the benefits, problems and issues of using these standards in the publishing ‘business’ environment…


Things to note…

• this is a briefing session about technologies…

• …but it is not intended to be overly technical

• you should leave with an understanding of what the key technologies are – but not necessarily be expert in them!


Important

• this is a briefing session…

…please feel free to ask questionsas we go through!


Context: metasearching and context sensitive linking


The ‘problem’…

• end-user often has access to large number of heterogeneous collections - full-text, A&I, images, video, data, etc. (e.g. thru JISC licening agreements)

• however, experience of these collections is less than optimal:– end-users not aware of available content– end-user has to interact with (search or browse)

multiple different Web sites to work across range of content

– content ‘discovery’ services not joined-up with delivery services


Or, to put it another way…

• from perspective of ‘data consumer’– need to interact with multiple collections of stuff

- bibliographic, full-text, data, image, video, etc.

– delivered thru multiple Web sites– few cross-collection discovery services (with

exception of big search engines like Google, but still some issues with use of Google – e.g. the ‘invisible Web’, the lack of metadata, keywords with multiple meanings, etc.)

• from perspective of ‘data provider’– few agreed mechanisms for disclosing

availability of content


A solution…

• an ‘information environment’• framework of machine-oriented services

allowing the end-user to– discover, access, use, publish resources across a range

of content providers– move away from lots of stand-alone Web sites...

• content providers expose metadata for– searching, harvesting, alerting

• develop end-user services and tools that bring stuff together…

• …based on open ‘standards’


End-user services and tools• tend to focus on library portal

(metasearch) tools (e.g. Encompass, MetaLib or ZPortal)

• but, there will be lots of user-focused services and tools…– subject portals developed within academia– reading list and other tools in VLE (e.g. externally hosted

by Sentient Discover)– commercial ‘portals’ (ISI Web of Knowledge, ingenta, Bb

Resource Center, etc.)– SFX service component (or other OpenURL resolver)– personal desktop reference manager (e.g. Endnote)


Link resolvers

• ‘discovery’ is only part of the problem…• in the case of books, journals, journal articles,

end-user wants access to the most appropriate copy

• need to join up discovery services with access/delivery services (local library OPAC, ingentaJournals, Amazon, etc.)

• need localised view of available services• linking services that provide access to the

most appropriate copy– user and institutional preferences, cost, access

rights, location, etc.


A shared problem space

• the problems outlined here are shared across sectors and communities– student or researcher looking for information from variety

of bibliographic sources– lecturer searching for e-learning resources from multiple

learning object repositories– researcher working across multiple data-sets and

compute servers on the Grid– a GP searching the National electronic Library for Health– school child searching BBC, museum and library Web

sites for homework project– someone searching across multiple e-government Sites– even someone looking to buy or sell a second-hand car…


Technologies• require global, standards-based, cross-

domain solutions…• cross-searching

– Z39.50 – Bath Profile, a profile of Z39.50 SRW (Search and Retrieve Web-service)(Web services implementation of Z39.50)

• harvesting– OAI-PMH - Open Archives Initiative Protocol

for Metadata Harvesting

• alerting– RSS - RDF/Rich Site Summary

• linking– OpenURL

…and cross-domainmetadata


Bluffer’s Guide to…

Dublin Core


Bluffer’s guide to DC

1. DC short for Dublin Core

2. simple metadata standard,supporting ‘cross-domain’resource discovery

3. original focus on Web resources but that is no longer the case – e.g. usage to describe physical artefacts in museums

4. current usage across wide range of sectors – academic, e-government, museums, libraries, business, semantic Web

http://dublincore.org/http://dublincore.org/


Bluffer’s Guide to DC

• ‘simple DC’ provides 15 elements (metadata properties)

• multiple encoding syntaxes including HTML <meta> tags, XML and RDF/XML (XML schema are available)

dc:title dc:contributor dc:source

dc:creator dc:date dc:language

dc:subject dc:type dc:relation

dc:description dc:format dc:coverage

dc:publisher dc:identifier dc:rights



7. relatively slow programme of adding new terms to ‘qualified DC’– new elements (e.g. dcterms:audience)– element refinements (e.g.

dcterms:dateCopyrighted)– encoding schemes (e.g. dcterms:LCSH and

dcterms:W3CDTF– 48 elements and 17 encoding schemes

http://dublincore.org/documents/dcmi-terms/http://dublincore.org/documents/dcmi-terms/



8. DC can be embedded into HTML pages but almost none of the big search engines will use it! Why? Lack of trust…– meta-spam– meta-crap– however, embedding DC in HTML may be

worthwhile if your own site search engine uses it

9. however, simple DC forms baseline metadata format for the OAI protocol…


Bluffer’s Guide to

OAI Protocol for Metadata Harvesting


OAI roots

• the roots of OAI lie in the development of eprint archives…– arXiv, CogPrints, NACA (NASA), RePEc, NDLTD, NCSTRL

• each offered Web interface for deposit of articles and for end-user searches

• difficult for end-users to work across archives without having to learn multiple different interfaces

• recognised need for single search interface to all archives– Universal Pre-print Service (UPS)


Searching vs. harvesting

• two possible approaches to building a single search interface to multiple eprint archives…– cross-searching multiple archives based on protocol like

Z39.50– harvesting metadata into one or more ‘central’ services

– bulk move data to the user-interface

• US digital library experience in this area indicated that cross-searching not preferred approach– distributed searching of N nodes viable, but only for

small values of N


Harvesting requirements

• in order that harvesting approach can work there need to be agreements about…– transport protocols – HTTP vs. FTP vs. …– metadata formats – DC vs. MARC vs. …– quality assurance – mandatory elements,

mechanisms for naming of people, subjects, etc., handling duplicated records, best-practice

– intellectual property and usage rights – who can do what with the records

• work in this area resulted in the “Santa Fe Convention”


Development of OAI-PMH

• 2 year metamorphosis thru various names– Santa Fe Convention, OAI-PMH versions 1.0, 1.1…– OAI Protocol for Metadata Harvesting 2.0

• development steered by international technical committee

• inter-version stability helped developer confidence

• move from focus on eprints to more generic protocol– move from OAI-specific metadata schema to mandatory

support for DC


Bluffer’s guide to OAI

1. OAI-PMH short for Open Archives Initiative Protocol for Metadata Harvesting

2. a low-cost mechanism for harvesting metadata records– from ‘data providers’ to ‘service providers’

3. allows ‘service provider’ to say ‘give me some or all of your metadata records’– where ‘some’ is based on date-stamps, sets,

metadata formats

4. eprint heritage but widely deployed– images, museum artefacts, learning objects, …

http://www.openarchives.org/http://www.openarchives.org/



5. based on HTTP and XML– simple, Web-friendly, fast deployment

6. OAI-PMH is not a search protocol– but use can underpin search-based services

based on Z39.50 or SRW or SOAP or…

7. OAI-PMH carries only metadata– content (e.g. full-text or image) made available

separately – typically at URL in metadata

8. mandates simple DC as record format– but extensible to any XML format – IMS metadata,

IEEE LOM, ONIX, MARC, METS, MPEG-21, etc.



9. metadata and ‘content’ often made freely available – but not a requirement– OAI-PMH can be used between closed groups– or, can make metadata available but restrict

access to content in some way

10.underlying HTTP protocol provides– access control – e.g. HTTP BASIC– compression mechanisms (for improving

performance of harvesters)– could, in theory, also provide encryption if

required



RSS


Bluffer’s guide to RSS

1. simple XML application for sharing (syndicating) ‘news’ feeds on the Web

2. RDF Site Summary or Rich Site Summary (depending on who you ask)

3. ‘news’ can be interpreted quite loosely, e.g. new items added to database

4. uses ‘channel’ and ‘item’ terminology

5. a ‘channel’ is an XML document that is made available on a Web-site – to update the channel, simply update the XML

http://www.eevl.ac.uk/rss_primer/http://www.eevl.ac.uk/rss_primer/



6. each ‘item’ has simple metadata (title, description) and URL link to resource (news story or whatever)

7. RSS also provides channel branding (logo, etc.)

8. three versions currently 0.9, 1.0 and 2.0 - 1.0 is based on RDF and is more flexible (but slightly more complex)(Also worth noting Atom – an attempt to resolve some of the tensions in RSS)

9. no single registry of all channels yet



10. fairly widespread usage, e.g. channels available from the BBC, Microsoft, Apple, … as well as from several academic sites and services (RDN, LTSN, …)

11.easy to use within ‘portals’ (e.g. uPortal)

12. lots of software and toolkits available – open source and commercial



OpenURLs


OpenURL roots

• the context– distributed information environment (e.g. the JISC IE)

– multiple A&I and other discovery services

– rapidly growing e-journal collection

– need to interlink available resources

• the problem– links controlled by external info services

– links not sensitive to user’s context (appropriate copy problem)

– links dependent on vendor agreements

– links don’t cover complete collection

a libraryperspective

?


The problem

• the context– distributed information environment (e.g. the JISC IE)

– multiple A&I and other discovery services

– rapidly growing e-journal collection

– need to interlink available resources

• the REAL problem– libraries have no say in linking

– libraries losing core part of ‘organising information’ task

– expensive collection not used optimally

– users not well served

a libraryperspective

?


The solution…

• do NOT hardwire a link to a single service on the referenced item (e.g. a link from an A&I service to the corresponding full-text)

• BUT rather– provide a link that transports metadata

about the referenced item– to another service that is better placed

to provide service links

OpenURL

OpenURLresolver

(link server)


Non-OpenURL linking

link destination

resolution of metadata into a link(typically a URL)

A&I servicedocument delivery

service

link source

link to referenced work .reference


OpenURL linking

link source.

user-specific

resolution of metadata &identifiers into services

reference OpenURLOpenURL

resolver

provision of OpenURL

linklink

destination

linklink

destinationlink

linkdestination

linklink

destination

transportation of metadata & identifiers

context-sensitive

A&I servicedocument delivery

service


Example 1

• journal article• from Web of Science to ingenta Journals


button indicatingOpenURL ‘link’

is available


OpenURL resolver offeringcontext-sensitive links,including link to ingenta


also links to other servicessuch as Google search for

related information


Example 2

• book• from University of Bath OPAC to Amazon


button indicatingOpenURL ‘link’

is available


OpenURL resolver offeringcontext-sensitive links,

including link to Amazon


also links to other servicessuch as Google search for

related information


Summary…ISI Web of Science

University of Bath OPAC

OpenURL resolver

ingenta

Google

Amazon

OpenURL SourceOpenURLResolver

OpenURL Target


Summary (2)

• OpenURL source– a service that embeds OpenURLs into its user-

interface in order to enable linking to most appropriate copy

• OpenURL resolver– a service that links to appropriate copy(ies) and other

value added services based on metadata in OpenURL

• OpenURL target– a service that can be linked to from an OpenURL

resolver using metadata in OpenURL


Bluffer’s guide to OpenURLs

1. standard for linking ‘discovery’ services to ‘delivery’ services

2. supports linking from OpenURL ‘source’ to OpenURL ‘target’ via OpenURL ‘resolver’

End-user

source resolver target

e.g. Web of Science e.g. ingenta

http://www.bath.ac.uk/openurl?genre=article&atitle=Information%20gateways:%20collaboration%20on%20content &title=Online%20Information%20Review &issn=1468-4527&volume=24&spage=40&epage=45 &artnum=1&aulast=Heery&aufirst=Rachel

BASEURL

http://www.niso.org/committees/committee_ax.htmlhttp://www.niso.org/committees/committee_ax.html



3. the OpenURL is a URL that carries metadata from the ‘source’ service to the user’s preferred resolver

4. resolver typically offered by institution

5. currently deployed OpenURLs are often version 0.1 - focus on bibliographic resources (books and journal articles)

6. version 1.0 (the standard) – more generic and extensible, e.g. could carry metadata about learning objects or research data



7. ‘sources’ need to maintain knowledge about end-user’s preferred resolver

8. resolvers and targets need to share knowledge about ‘link-to’ syntaxes

9. most library automation vendors will either have (or be developing) an OpenURL resolver solution for their customers

10.some open-source solutions also available – but expect to work quite hard with these


Discussion…


Summary


Summary

• protocols presented here fill space between ‘information providers’ and other services (‘portals’, VLEs, etc.)– allow integration of remote information

resources more seamlessly– allow separation of ‘discovery’ and ‘content

delivery’– enable user-focused, context-sensitive linking– can be viewed as ways of getting users to your

site

• but… there are some issues to beware of


What can you do?

• consider exposing metadata about your content for harvesting (or searching)

• consider making ‘alerting’ channels available• consider supporting use of OpenURLs for

linking to appropriate-copy• consider how your content will be used in e-

learning context• consider how external services ‘link to’ your

resources (i.e. support persistent deep linking to your content)

Open for Business - Open Archives, OpenURL, RSS and the Dublin Core

Education

Transcript of Open for Business - Open Archives, OpenURL, RSS and the Dublin Core