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DNER Architecture

DNER Architecture. Andy Powell UKOLN, University of Bath a.powell@ukoln.ac.uk www.ukoln.ac.uk JOIN-UP Seminar on Linking Technologies, Edinburgh 6 March 2001.

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DNER Architecture

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  1. DNER Architecture Andy Powell UKOLN, University of Bath a.powell@ukoln.ac.uk www.ukoln.ac.uk JOIN-UP Seminar on Linking Technologies, Edinburgh 6 March 2001 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.

  2. What is the DNER? • DNER is an information environment (a set of services) that enables people to access and use a wide variety of resources • ‘resources’ are… • services / content • local / remote • primary / secondary, data / metadata • digital / physical • JISC funded / not JISC funded • policy controlled / non-policy controlled • ‘access and use’ includes • discover / locate / access • use / reuse / create • receive / provide / collaborate

  3. Functional model authenticate landscape • move from user-need to resource on desktop (physical or digital) • three stage ‘discovery process’ • ‘landscape’ and ‘survey’ - collection level • ‘discover’ and ‘detail’ - item level • iterative process • final ‘detail’ phase provides information about how to request instance of resource • ‘detail’ may involve resolving identifier or metadata for resource using ‘resolver’ survey discover useRecord detail request authorise access useResource

  4. DNER information flow • process is iterative at all stages • DNER not just a ‘provider to user’ flow • users are both recipients of and creators of both primary content, secondary content and metadata • DNER architecture needs to support • collaboration and • creation • …as well as discovery, etc. • however, current work on architecture doesn’t really address this.

  5. Systems architecture • framework for network of shared services • DNER as coherent whole rather than lots of stand-alone services • two areas in particular... • discovery • finding stuff from multiple content providers • locate/request/deliver • streamlining access

  6. Discover • in order to allow end-user to discover seamlessly across several network services... • services need to expose content for machine use (m2m) • expose metadata for • searching • harvesting • alerting • develop services that bring stuff together • portals

  7. 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 - search, share and alert)

  8. Thin portal Content Web Web Web Web Authentication Authorisation Collect’n Desc Portal HTTP End-user

  9. Thick portal - searching Content Web Web Web Web Authentication Z39.50 Bath Profile Authorisation Broker Collect’n Desc Portal Service Desc HTTP End-user

  10. Searching and Z39.50 • cross-searching based on Z39.50 and Bath Profile • pragmatic rather than dogmatic choice • Z39.50 only real option at this stage • can move to other options (e.g. W3C query language) when appropriate

  11. Thick portal - sharing Content Open Archives Initiative Web Web Web Web Authentication Authorisation Aggregator Collect’n Desc Portal Service Desc HTTP End-user

  12. Open Archives Initiative • OAI Metadata Harvesting Framework • simple mechanism for sharing metadata records • records shared over HTTP... • ... as XML (using XML Schema) • client can ask metadata server for • all records • all records modified in last ‘n’ days • info about sets, formats, etc. • See <http://www.openarchives.org/>

  13. Thick portal - alerting Content Web Web Web Web RSS Authentication Authorisation Aggregator Collect’n Desc Portal Service Desc Email HTTP End-user

  14. RSS • Rich/RDF Site Summary • XML application for syndicated news feeds • pointers and simple descriptions of news items (not the items themselves) • has been transitioned to more generic RDF/XML application (RSS 1.0) • no querying - just regular ‘gathering’ of RSS file http://www.ukoln.ac.uk/metadata/rssxpress/

  15. Resource identification • ‘discovery’ results in metadata about a resource that may include its identifier or a locator • for Web resources a URL is common • identifier is persistent • locator also 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

  16. 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 VADS page) • metadata about the resource (e.g. description of image from VADS or subject gateway) • probably need to identify all of these • need guidelines on good practice for use of URLs • investigate use of DOIs

  17. Resolving identifiers • may need to resolve the metadata, identifier or locator into information about how to request a particular instance of the resource • need to find appropriate copy • resolution 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 end-user?

  18. OpenURL • metadata, identifier or locator effectively forms a ‘citation’ for the resource • OpenURL provides mechanism for encoding citation for a resource as a URL • OpenURL = baseURL + description • baseURL provides location of a ‘resolver’ • description is either a global identifier (e.g. a DOI or ISBN) or a description (a citation) or mixture • http://sfx.bath.ac.uk/sfxmenu?genre=book&isbn=1234-5678

  19. Locate and identifiers Web resource Journal issue Book Article Discovery services Discover URI DOI ISBN Citation/metadata Persistent ‘identifiers’ - context independent OpenURL or Z39.50 request Locate Locate services (resolvers) Resource URL Delivery service URL or Resource URL Transient ‘locators’ - context sensitive Request

  20. OpenURL resolver Content Delivery service Authentication Authorisation Collect’n Desc Portal OpenURL Service Desc Resolver HTTP End-user

  21. DNER shared services • authentication • authorisation/profiling • collection description • service description • resolution • user preferences • thesauri/terminology • metadata registry • (ratings, terms & conditions) key desirable

  22. Summary provision content shared services m2m interfaces brokers and aggregators middleware fusion portals presentation

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