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The ‘discovery to delivery’ DLF reference model
Andy Powell, UKOLN, University of Bath
JISC-CETIS Conference, Edinburgh, November 2005
www.bath.ac.uk
a centre of expertise in digital information management
www.ukoln.ac.uk
JISC-CETIS Conference, Nov 2005 2
Contents
• this talk summarises some draft work that has been done as part of the DLF Abstract Service Framework Working Group to develop a ‘reference model’ for the ‘discovery to delivery’ space– history – the IE– context - the DLF Abstract Service Framework
Working Group– terminology – the DLF model and ‘reference model’– the d2d reference model– issues
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History - the JISC IE
• attempt to allow services offered within the JISC community to be joined together more seamlessly– JISC-funded, institutional, other
– allow users to ‘discover’, ‘access’ and ‘use’ resources – d2d
– not just library resources – wide range of heterogeneous resources
• a set of standards/interfaces• essentially ‘service oriented’
but work pre-dated thatuse of terminology
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Context – the DLF
• Digital Library Federation – consortium of largely US research libraries but growing international membership – e.g. the British Library
• DLF Abstract Service Framework Working Group - applying a ‘service oriented’ approach to library services– see how library services fit into world populated by
Google, Amazon, eLearning systems, Grid services and eResearch, Web 2.0, etc.
– unbundle monolithic library systems into ‘service’ components
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BIG DISCLAIMER
• everything I’m about to tell you may be wrong!• this presentation discusses work that is
currently in progress• the terminology may well change (in fact it is
already changing)• the use of the DLF model for things like d2d
may well change (in fact it is already changing)
• DLF keen to work with JISC on the eFramework to reach consensus
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Terminology - the DLF model
Business requirement
Business process
Business function
Abstract service
Service binding
Deployed service
Business entity
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Terminology - the DLF model
Business requirement
Business process
Business function
Abstract service
Service binding
Deployed service
A business requirement is identifiable segmentof an organisation’s overall mission.
A business process is an identifiable portion of a business requirement. Business processes may be made up of business functions.
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Terminology - the DLF model
Business requirement
Business process
Business function
Abstract service
Service binding
Deployed service
Abstract services are discrete pieces of networked functionality (supporting a business process/function).
A service binding is an instantiation of an abstract service – a concrete data representation, API, Web service description, etc.
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Terminology - the DLF model
Business requirement
Business process
Business function
Abstract service
Service binding
Deployed service
A deployed service is a service binding available at a specific location on the network.
Business entity
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Terminology - the DLF model
Business requirement
Business process
Business function
Abstract service
Service binding
Deployed service
A business entity is something of interest – typically represented by metadata. The things that services are about.
Business entity
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DLF reference model
• a DLF reference model is…• a document that describes all the
features of this model as used to meet a particular business requirement
• not clear how formalised this document can/should be?– human text vs.– UML (or some other modelling language)
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Applying the DLF model…
• …to the discovery to delivery (d2d) ‘business requirement’ – the requirement for people to be able to discover
and access resources in the context of their learning and/or research activities
• in this case the requirement is met by allowing the end-user to undertake a number of ‘business functions’– enter, survey, discover, detail, request, deliver– each function is documented using UML use
cases
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Enter
• entering the ‘system’• likely to have to be authenticated before
accessing resources– e.g. providing an Athens username
• may result in a personalised view of the landscape being presented
enter
authenticate buildLandscape
initiate
user provider
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Survey/discover
• 'survey‘ is about identifying the collections that are of interest
• 'discover' drills down into each of the collections identified during the initial survey
• same ‘discovery’ strategies used in each
discoverinitiateuser provider
survey
useSavedRecord search
initiate
useSavedRecord search
browse alert initiate
assistQuery
assistQuery
browse alert initiate
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Detail
• builds up knowledge about a particular resource– locations, formats, ratings and annotations,
terms and conditions, etc.
• find out enough to be able to request the resource
detail
locate getFormats
initiate
user providergetRatings getConditions
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Request/deliver
• attempt to obtain resource– HTTP GET– inter-library loan– buying book from Amazon– etc.
• some level of authorisation may be required before delivery
request
deliver
authorise
initiate
initiate
initiateuser provider
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Abstract services
• businessfunctionsandprocessessupportedby services
Enter Survey Discover Detail DeliverRequest
JISC IED2D
Authentic-ation
UserPreferences
ServiceRegistry
Search
Alert
Terminology
MetadataSchemaRegistry
Harvest
IdentifierResolver
Rating/Annotation
LinkServer
Terms andConditions
Authorisation
Authorisation
Authorisation
Terminology
Business Requirement
Business Process
Abstract Service
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Abstract services
• each abstract service documented in terms of its behaviour, inputs, outputs and intelligence (the business entities it needs to know about)
• for example:
Search (Discover)Behavior: Accepts a structuredquery and issues a set of metadatarecords (a result set) in responseto the query.Intelligence: SchemaData in: Structured queryData out: Metadata record set
Link server (Detail)Behavior: Provides informationand/or links (i.e. URLs) associatedwith a resource based on ametadata record about thatresource.Intelligence:Data in: Metadata recordData out: Information and links
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Service bindings
• each abstract service instantiated using one or more service bindings
• for example:
SearchZ39.50 (Bath Profile)SRW/SRUDC, IEEE LOMMETS, IMS-CP, MPEG-21 DIDL
Link serverOpenURL
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Deployed services
• the set of service bindings deployed on the network
JISC-fundedcontent providers
institutionalcontent providers
externalcontent providers
brokers aggregators catalogues indexes
institutionalportals
subjectportals
learning managementsystems
media-specificportals
end-userdesktop/browser pr
esen
tatio
n
fusion
prov
isio
n
OpenURLlink servers
shared infrastructure
authentication/authorisation(Athens)
institutional profilingservices
terminology services
service registries
identifier services
metadata schema registries
© Andy Powell (UKOLN, University of Bath), 2005
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Issues - workflow
• UML use-cases as presented here tend to imply a linear workflow– enter, survey, discovery, detail, request, delivery
• in practice, services likely to be joined together by end-users inarbitrary order asthey see fit
• not possible topre-determineworkflow usedin the wild?!
survey/discover
useRecorddetail
request
deliver
useResource
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Issues – enter function
• ‘enter’ function OK if thinking about monolithic resource discovery application, e.g. a ‘portal’
• but doesn’t sit comfortably in scenario where end-user is joining services together to suit them
• authentication, authorisation, user-profiling likely to happen at multiple places in workflow– e.g. consider user moving from Google to
Connotea to OpenURL link server to library OPAC to A&I service to lngenta Journals …
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Issues – survey vs. discover
• this work is draft and undergoing inactive change
• not clear that this is the right breakdown of ‘business functions’
• ‘survey’ vs. ‘discover’ distinction not clear – particularly since same strategies might be used to find ‘annotations’, ‘terms and conditions’, etc.
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Issues – use of UML
• not building monolithic applications• rather, we are building loosely-coupled
services that will be joined together and choreographed by a variety of applications
• use of UML in this context is somewhat ‘unusual’
• might be better to use other approaches instead of/as well as UML– e.g. Mindmaps
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Discussion…
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