Notes

Outline

Building Reliable Distributed Information Spaces Carl Lagoze CS 430 10/22/2002

Characteristics of a library Functions Selection Access Organization User support Preservation Characteristics Standardized Professionalized Service-oriented In it for the long-haul Conservative Trustworthy Expensive (human centric)

Perspective on the Budget

Library in current environment “I don’t do libraries” – anonymous Cornell undergrad to Bob Constable How do you use the library? Go to the library to study? Go to the library to do research? Talked to a reference librarian? Use the library gateway or electronic resources?

Characteristics of the Web Decentralized/Anarchic/Illegal Agreements are technical (at best) Roles are undefined and fluid Immediate Ephemeral Integrity not established Anonymous (or “no one knows you are a dog”)

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What is a Digital Library?

What is a Digital Library?

Many facets of the problem/solution

Technical Trade-offs

National Science Digital Library (NSDL) Goal: Reform science education in the US in the digital age $25M in funding 2002-2006 Over 80 institutional grants for collections, services, core infrastructure (technical, economic, organizational) Cornell is primary technical development partner Carl Lagoze, Director of Technology http://www.nsdl.org

Building service and knowledge layers over a variety of resources for a variety of users

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Resources for Core Integration

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Levels of interoperability

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Function versus cost of acceptance

Z39.50 principles

State

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Open Archives Initiative Protocol for Metadata Harvesting Low-barrier protocol for exposing structured information (metadata) from cooperating repositories Provides opportunity for building comprehensive service network http://www.openarchives.org

OAI-PMH: A simple two party model for sharing structured information

Resource discovery over distributed collections

OAI-PMH Key technical features Deploy now technology – 80/20 rule Simple HTTP encoding Foundation of established XML standards Multiple metadata formats Repository partitioning (sets) Selective harvesting (sets and dates) Clean partition between core and implementation-specific extensions Multiple item-level metadata Collection level metadata

OAI Verbs Identify – repository characteristics ListMetadataFormats – DC required ListSets – repository paritioning ListRecords – (selectively) harvest metadata ListIdentifiers – (selectively) harvest metadata identifiers GetRecord – known item retrieval

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Metadata Repository

Importing metadata into the MR

Exporting metadata from the MR

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The Metadata Repository as a Resource Records are exposed through Open Archives Initiative harvesting protocol. Core Integration team will provide some services based on the metadata repository. The architecture encourages others to build services.

Building on the basics Gathering resources from the open web Automated collection aggregation Automated metadata generation Content of resource Context of resource Automated quality assessment Annotation, review, and aggregation environment

If you find this all interesting CS502 – Architecture of Web information Systems