Augmenting interoperability across scholarly repositories

RESEARCHLIBRARYAugmenting Interoperability across Scholarly Repositories

JISC CNI Conference, York, UK, July 6th 2006Herbert Van de Sompel

Augmenting Interoperabilityacross Scholarly Repositories

Herbert Van de SompelResearch Library

Los Alamos National Laboratory, USA

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This work was supported by NSF award number IIS-0430906 (Pathways)



Pathways Project

• NSF grant number IIS-0430906• http://www.infosci.cornell.edu/pathways/• PIs: Carl Lagoze, Sandy Payette, Herbert Van de Sompel, Simeon

Warner• Research Participants: Lyudmila Balakireva, Jeroen Bekaert,

Xiaoming Liu, Chris Wilper, Zhiwu Xie



Meeting in NYC, April 20-21 2006

• Supported by Microsoft, Mellon Foundation, Coalition forNetworked Information, Digital Library Federation, JISC

• Representatives from institutional Repository projects, scholarlycontent Repositories, Registry projects, various projects that touchon interoperability

• See http://msc.mellon.org/Meetings/Interop/ for Agenda,Participants, Topics & Goals, Terminology, Presentations, Prototypedemonstration.

• Report available July 2006



And more discussions with the community

• Panel at JCDL 2006, Chapel-Hill, NC• IATUL 2006, Porto, Portugal• ElPub 2006, Bansko, Bulgaria• Meeting at the University of Southampton, UK



Context: the Repository model

Repository

An environment consisting ofDigital Object Repositorieswith a Long Life Expectation:

o Scholarly repositories- Institutional

repositories- Discipline-oriented

repositories- Publisher’s repositories- Dataset repositories- …

o Cultural heritagerepositories

o Preservation archiveso Educational repositories



Context: compound digital objects

Digital Object

Objects of scholarlycommunication system areincreasingly compound innature, simultaneouslyconsisting of:

• Multiple media types• Multiple content types

o Papers,o Datasets,o simulations,o software,o dynamic knowledge

representations,o machine readable chemical

structures

id



Context: the Repository model

• We must leverage the value of the materials that becomeavailable in those distributed Repositories.

• Think about these Repositories as active nodes in a globalenvironment, not as passive local nodes

o These Repositories are about facilitating the use and re-use of materials in many contexts

o These Repositories are the starting point of value chains

• In order to enable value chains, we need to augmentinteroperability across repositories



Selective collecting

Motivation 1 : Richer cross-Repository services

service

Distributed Repositories provide sourcematerials for cross-Repository overlayservices such as discovery services

Need: digital object representation,harvesting interface, datastreamsemantics



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id

idrecombine & add value

Motivation 2 : Scholarly communication workflowDistributed Repositories at the basis of adigital scholarly communication system.Scholarly communication as a globalworkflow across those Repositories

Need: digital object representation,obtain interface, put interface



Augmenting interoperability across RepositoriesD

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Individual Data Models and Services

Shared Data Model and Services



Considerations re interoperable framework

• Scholarly communication is a long-term endeavor:• Need abstract definitions of Repository interfaces that can be

instantiated on the basis of various technologies as time goes by• Repository interfaces need to work with whichever type of

identifier (current and future) because Repositories will usewhichever type of identifier

• Value chains do not require transfer of all digital objectcontent

• The content that needs to be transferred depends on the natureof the value chain

• Recording a chain of evidence of a value chain requires finegranularity of identification

• Not only identifier of the digital object but also of therepository



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Augmenting interoperability across Repositories

m Pathways Core Data Model for Cross-Repository services

Bekaert, Jeroen, Xiaoming Liu, Herbert Van de Sompel, Sandy Payette, Carl Lagoze, andSimeon Warner. Pathways Core: A Data Model for Cross-Repository Services. 2006.Poster for JCDL 2006. http://public.lanl.gov/herbertv/papers/pathways_core_poster_submit.pdf




• A Surrogate is available for every Digital Object• A Surrogate is a representation of the DigitalObject according to the Pathways Core data model

• The representation is uniform across repositories;not tied to identifier type, content type, applicationdomain.• The Surrogate is what is used in the value chains;the Surrogate is used at Obtain, Harvest and Putinterfaces.o Expresses properties and access points for theDigital Object (see later)

o The Surrogate for a specific Digital Object canchange over time

m Pathways Core Surrogates (currently XML/RDF)




• The Surrogates provide By-Reference access toconstituent datastreams of Digital Objects

• Full asset transfer is only required for certainapplications• Static asset transform may be undesirable fordynamic objects => Live references• Avoid IP issues at the level of the interoperabilityframework

• The idea is that the Surrogate itself is notencumbered by IP issues; attach - by definition -a liberal Creative Commons license to Surrogates• Allow Surrogates to flow freely independent ofbusiness models of the underlying content





• A Surrogate expresses access points andproperties of a Digital Object, e.g.:

• Location of content streams

• providerInfo: the keys necessary to Obtain afresh Surrogate at some later point in time:

• (Repository identifier, preferredIdentifier,versionKey)

• Lineage: A Surrogate expresses itspredecessor(s)

• == providerInfo in previous life• semantic: A Surrogate expresses the type ofcontent.




Obtain interface: a Repository interface that supports the request ofservices pertaining to individual Digital Objects (including theircomponent Datastreams). The core service is the request of aSurrogate for a Digital Object.


Obt

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vest Harvest interface: a Repository interface that exposes Surrogates for

incremental collecting/harvesting.

Put Put interface: a Repository interface that supports submission of oneor more Surrogates into the Repository, thereby facilitating theaddition of Digital Objects to the collection of the Repository.



Surrogate is at the core of the value chain

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Basis for a Network of Linked Digital Objects



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(provider,preferredIdentifier,

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Augmenting interoperability across scholarly repositories

Technology

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