1. Some thoughts on OpenURL version 1.0 Herbert Van de Sompel Los Alamos National Laboratory – Research Library NISO AX meeting, Getty Museum, May 30-31 2002

2. 1. The EBNF 2. Extensibility 3. Registries Topics

3. 1. The EBNF human readable, construction-oriented: insignificance of order not encoded relation private zones and Referrer zone not encoded ? optional administrative zone ? by-reference mechanism for all entities ? vendorId:dbaseId type problem ? what is covered by URI scheme ? what exactly is network-location

4. 2. OpenURL extensibility registration: by-value formats (referent) by-reference formats (referent, requester, ?, ?, ?) namespace identifiers (referent, requester, referrer, referring-entity, service-type) local prefix – referrer id required namespace-identifiers (referent, requester, referrer, referring-entity, service-type) by-value format identifiers (referent) by-reference format identifiers (referent, requester, ?, ?, ?) private zones – referrer id required (referent, requester, referrer, referring-entity, service-type)

5. 3. OpenURL Registries Inventory of required registries OpenURL Format Registry Registry for by-value and by-reference formats Architecture for Format Registry Policy issues Identifier Registry de-facto (URI scheme) OpenURL identifier registration Deployment strategy

6. Inventory of required registries by valueby refidentifier referentxxx referrer-?x refer-entity-?x requester-xx service type-?x resolver---

7. Inventory of required registries by valueby refidentifier referentxxx referrer-?x refer-entity-?x requester-xx service type-?x resolver---

8. OpenURL Registries - formats local formats – no registry single OpenURL Format Registry same type can occur as different entities (think article as referent and referring-entity) indicate by-value and/or by-reference nature mandatory definition of registered formats by means of XML Schema in sync with trend in our focus community simplifies handling by-ref: the doc that is pointed at is always XML instance doc that can be validated local formats can be whatever see examples journal.xsd, jissue.xsd, jarticle.xsd

9. OpenURL Registries - formats using XML Schema to define by-value formats: the Schema: flat structure required: root and single level down format-identifier == name of root-element of Schema metadata-tags == names of direct childs of root- element can be used as by-reference could provide template to support creation the Registry: XML Schema validation guarantee uniqueness of root-element name reject Schema with underscores in child element names reject id, pid, sid, submit as element names

10. OpenURL Registries - formats using XML Schema to define by-reference formats: the Schema: no limitations on Schema structure format-identifier: ? name of root-element of Schema ? schemaLocation (uri flavor) ? XML Namespace URI can not necessarily be used as by-value the Registry: XML Schema validation ? guarantee uniqueness of root-element name (probably not feasible)

11. linking servers registrars XML Schema URL 1 XML Schema URL 2 XML Schema URL n registration polling OAI-PMH harvesting central repository OAI-PMHOAI-PMH PollPoll regis.regis. user service registry model

12. registrars XML Schema URL 1 XML Schema URL 2 XML Schema URL n Goal: inform linking servers re Schema ease of admin for all parties involved limit human overhead

13. registrars XML Schema URL 1 XML Schema URL 2 XML Schema URL n registration central repository regis.regis. Registry: schemaLocation registration date mirror of Schema

14. registrars XML Schema URL 1 XML Schema URL 2 XML Schema URL n registration central repository regis.regis. polling PollPoll Poll: fetch schema at schemaLocation log failure/success compare fetched Schema with mirror changed => replace mirror removed => deregistered

15. registrars XML Schema URL 1 XML Schema URL 2 XML Schema URL n registration polling central repository OAI-PMHOAI-PMH PollPoll regis.regis. OAI repo: record-ids = schemaLocation oai_dc record : registration info (de)registration datestamp xsi record : mirror schema schema update datestamp poll record : process info recent poll datestamp

16. linking servers registrars XML Schema URL 1 XML Schema URL 2 XML Schema URL n registration polling OAI-PMH harvesting central repository OAI-PMHOAI-PMH PollPoll regis.regis. user service

17. OpenURL Registries – formats – policy issues ? peer-reviewed or open approach to registration if peer-reviewed ? what are the criteria ? who does the review (for which formats) if open ? how to avoid (unnecessary) proliferation of Schema ? what constitutes a deregistration ? what to do with mirror-schema in case of deregistration ? which kind of party should operate the registry

18. OpenURL Registries – namespace identifiers local identifiers – no registry URI-scheme identifiers – what does it cover? ? require RFC ? require IANA registration ? based on informal W3C registry ? compile list based on the above OpenURL-defined identifiers ? registration criteria ? technique for namespace description ? relationship to formats

19. OpenURL Registries – deployment need something for formats and namespace-identifiers starting with test-phase proposal: restrict registered formats: 6 by-value formats select some by-ref formats: oai_dc, marc21, … registered namespace identifiers: cf OpenURL 0.1: doi, oai, pmid, bibcode, dns URI identifiers: select a few: http, doi, dns, … allow no further registration provide helpdesk host at library site, where OpenURL experience is available

20. OpenURL Registries – deployment in parallel with test-phase, define: registry requirements: technical, functional, policy implementation plan