Transcript presentation source

Accessing a national digital
library: an architecture for
the UK DNER
Andy Powell
ELAG 2001, Prague
7 June 2001
UKOLN, University of Bath
[email protected]
UKOLN is funded by Resource: The Council for Museums, Archives and Libraries, the Joint
Information Systems Committee (JISC) of the Higher and Further Education Funding Councils,
as well as by project funding from the JISC and the European Union. UKOLN also receives
support from the University of Bath where it is based.
Contents
• what is the DNER
• vision
• content
• functionality
• network systems architecture
• discover
• access
• <www.dner.ac.uk/architecture>
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What is the DNER?
• Distributed National Electronic Resource
• …but the name may change!
• An initiative of the Joint Information
Systems Committee (JISC)
• Not new… in that JISC has been funding
provision of collections of information for a
long time
• …but
• DNER more coordinated
• provided within shared architectural
framework
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The vision...
• a national digital library... for higher and further
education
• a distributed resource supporting learning and
research in the UK
• a managed collection of resources
• heterogeneous… bibliographic, images, data,
video, geospatial, etc.
• an information environment that enables
people to discover, access and use a wide
variety of quality assured resources
• heterogeneous, services / content, local / remote, digital
/ physical, JISC funded / not JISC funded
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DNER scope by content
External
Institutional
Secondary Content
RDN
A&I
COPAC
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Northern
Light
Primary Content
Map data
Full-text
images
statistics
Funded
DNER collections
• content typically in the form of ‘collections’
• where collection is one or more items
• collections of stuff (text, images, data, ...)
• collections of metadata about stuff (e.g subject
gateway’s, library catalogues)
• local collections, ‘JISC’ collections, other
collections
• network services make digital collections
available at digital ‘locations’
• real services make physical collections
available at physical ‘locations’
• people access content through services
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DNER services
• a variety of ‘content provision’ services
make current digital collections available
• most are Web-based (some use of
Z39.50)
• in some cases ‘we’ (the education
community) develop and control the
services that make collections available
• in some cases collections are tightly
bound to their user-interfaces - i.e.
collection owners control form of access
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DNER scope by function
• simple underlying functional model
• discover, access, use
• characterised in the solution to two
problems
• portal problem - how to provide seamless
discovery across multiple content providers
• appropriate-copy problem - how to provide
access to the most appropriate copy of a
resource (given access rights, preferences,
cost, speed of delivery, etc.)
• also needs to support collaboration and
creation but not considered here
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Current service architecture
Content
(local and
remote)
Web
Web
Web
Web
Authentication
Authorisation
Current services
offer mix of
discover, access
and use
functionality
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End-user
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End-user needs
to join services
together
manually - as
well as learning
multiple user
interfaces
Information environment
• current services are human-oriented
• DNER architecture provides framework
for shared machine-oriented services
• DNER as coherent whole rather than lots
of stand-alone services
• two areas in particular...
• discover
• finding stuff across multiple content providers
• access
• streamlining access to appropriate copy
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Discover
• want to allow end-user to discover across
several network services...
• to support this, services need to expose
content for machine to machine (m2m)
use
• expose metadata about their content for
• searching
• harvesting
• alerting
• develop services that bring stuff together
• portals
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Portals
• portals provide access to multiple network
services
• there will be many kinds of portals...
• subject portals
• data centre portals
• institutional portals
• personal portals (agents)
• virtual learning environments
• thin portals (shallow linking)
• thick portals (deep linking, richer discovery
and use functionality)
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Searching
Content
Web
Web
Web
Web
Authentication
Authorisation
Broker
Z39.50
Bath Profile
Collect’n Desc
Service Desc
Portal
HTTP
End-user
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Z39.50 - Bath Profile
• search and retrieve
• support portal and broker cross-searching
• Bath Profile based on existing profiles
• cross-domain focus (in part)
• unqualified Dublin Core
• DC XML records
• DTD-based rather than XML Schema
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Sharing
Content
Web
Web
Web
Open
Archives
Initiative
Web
Authentication
Authorisation
Aggregator
Collect’n Desc
Service Desc
Portal
HTTP
End-user
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Open Archives Initiative
• OAI Metadata Harvesting Framework
• simple mechanism for sharing metadata
records
• records shared over HTTP...
• ... as XML (using XML Schema)
• unqualified Dublin Core
• client can ask metadata server for
• all records
• all records modified in last ‘n’ days
• See <http://www.openarchives.org/>
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Alerting
Content
Web
Web
Web
Web
RSS
Authentication
Authorisation
Aggregator
Collect’n Desc
Portal
Service Desc
Email
HTTP
End-user
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RSS
• RDF Site Summary
• RDF/XML application for syndicated news
feeds (RSS 1.0)
• pointers and simple descriptions of news
items (not the items themselves)
• makes use of DC elements
• previous versions based on XML (RSS 0.9)
• no querying - just regular ‘gathering’ of
RSS file
<http://www.ukoln.ac.uk/metadata/rssxpress/>
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Common sense
• need shared understanding and metadata
practice across whole range of services
• need to agree ‘cataloguing guidelines’
and terminology in 4 key areas
• subject classification
• audience level (who is this resource aimed
at?)
• resource type (what kind of resource is this?)
• certification (who has created this resource?)
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Access
• discovery phase results in metadata
about a resource
• metadata will include its identifier or a
locator
• for Web resources a URL is common
• identifier/locator needs to be persistent
• enable lecturers to embed it into learning
resources
• enable students to embed it into multimedia
essays
• enable people to cite it
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Identifiers/locators
• also need to think about what is
identified...?
• the resource (e.g. an image)
• the resource in context (e.g. image
embedded into Web page)
• metadata about the resource (e.g. description
of image)
• probably need to identify all of these
• need guidelines on good practice for use
of URLs
• investigate use of DOIs
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Resolving identifiers
• may need to resolve the metadata,
identifier or locator into information about
how to request a particular instance of the
resource
• this is done using resolvers
• resolvers find appropriate copy
• location is context sensitive - need to know
who end-user is, where they are and what they
have access to
• may be best carried out locally to enduser?
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OpenURL
• metadata, identifier or locator forms a
‘citation’ for the resource
• OpenURL - way to encode citation for a
resource
• http://sfx.bath.ac.uk/sfxmenu?genre=book
&isbn=1234-5678
• OpenURL resolves differently for different
people
• my OPAC, my online bookstore vs.
your OPAC, your online bookstore
• bibliographic focus currently...
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OpenURL resolver
Content
Delivery
service
Authentication
Authorisation
Collect’n Desc
Service Desc
OpenURL
Portal
Resolver
HTTP
Inst’n Profile
End-user
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Information environment
provision
content
infrastructure
shared
services
m2m
interfaces
portals
presentation
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brokers
and
aggregators
fusion
Summary
• people, institutions, content, services
• discover, access, use
• discover - search (Z39.50/Bath Profile), share
(OAI), alert (RSS) - Dublin Core metadata
• access - OpenURL and resolvers
• services
• presentation, fusion, provision, infrastructure
• portals, brokers and aggregators, content
providers, shared services
• cataloguing rules
• subject, type, audience, certification
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