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OAI and OAI-PMH
- 1. OAI & OAI-PMH Albulena Bruncaj LIS 882 Metadata for Internet Resources
- 2. What is OAI? The Open Archives Initiative OAI is a framework that deals with interoperability standards for digital resources Traces its roots to the open access and institutional repository movements (e-prints) It is “explicitly in transition” Their goal is to define a “low-barrier” framework for cross-repository interoperability
- 3. OAI-PMH – A Brief History The Open Archives Initiative Protocol for Metadata Harvesting The framework provides a technical mechanism for harvesting metadata from repositories Santa Fe meeting (1999) Cross-searching multiple archives based on Z39.50 or harvesting metadata into one or more "central" services in a bulk move of data? OAI-PMH 1.0/1.1 followed by OAI-PMH 2.0
- 5. OAI-PMH
- 6. Why use OAI-PMH? Easily and rapidly deployed because it is XML and HTTP based Interoperability Visibility Can use a single search interface
- 7. Who Participates? Two classes: Data Providers Service Providers 1357 registered OAI-PMH repositories — http://www.openarchives.org/Register/BrowseSites
- 8. Multiple data & service providers
- 9. Aggregators
- 10. Repositories As defined by OAI-PMH, a repository is a network-accessible server that exposes metadata to harvesters Three entities related to this accessible metadata: Resource Item Record
- 11. Records header (mandatory) identifier Datestamp (YYYY-MM-DD) setSpec elements status attribute for deleted item metadata (mandatory) XML encoded metadata with root tag, namespaces repositories must support Dublin Core, may support other formats about (optional) rights statements provenance statements
- 12. setSpec Sets are optional Enable a logical partitioning of repositories, but they are not necessarily hierarchical Not necessarily exhaustive of content Helps facilitate selective harvesting, however Publication type Document type Content sets
- 13. The Fun Part! OAIster http://oaister.worldcat.org/
- 14. Requests & Reponses Both use HTTP Request types (also called the “verbs”) Identify ListMetadataFormats ListSets ListIdentifiers ListRecords GetRecord
- 16. DSpace OAI-compliant Free, out-of-the-box software that enables access to digital content Examples: http://timea.rice.edu/browse.jsp http://modiya.nyu.edu/
- 17. CONTENTdm CONTENTdm is a software used for the management of digital collections Widely used Metadata in CONTENTdm can be harvested through OAI-PMH Allows collection curators to extend basic Dublin Core schema to include locally defined fields Example: http://content.lib.washington.edu/
- 18. CONTENTdm – Tension At minimum, simple Dublin Core is required CONTENTdm offers an easy way to make their metadata (and thus, digital collections) available while simultaneously providing curators with the means to create local, non-standardized metadata
- 19. Issues with OAI-PMH Libraries face the challenge of creating metadata that both meets the requirements of local practices in granularity (e.g., putting certain content in fields not harvestable by others) and wanting to share their digital collections widely Is there any solution? Or are we all left to figure out our library’s balance on our own?
- 20. Questions?
- 21. Bibliography An overview of OAI OAI-PMH. 12 Nov. 2010. Retrieved from http://www.slideworld.org/viewslides.aspx/An-Overview-of-OAI--OAI-PMH-ppt-2369922 Han, M., Cho, C., Cole, T.W., and Jackson, A.S. “Metadata for special collections in CONTENTdm: How to improve interoperability of unique fields through OAI-PMH.” Journal of library metadata, 9(3/4), 213-238. OAI. 12 Nov. 2010. Retrieved from http://www.openarchives.org/ "OAI-PMH online tutorial." Open Archives Forum. 12 Nov. 2010. Retrieved from http://www.oaforum.org/tutorial/ Zeng, M.L., and Qin, J. (2008). "Metadata repositories." In Metadata (224-232). New York: Neal-Schuman.
Notes de l'éditeur
- Bullet 1: Don’t be deceived by the word “Archive” in the title—this isn’t what archivists, as we know them, work with. Bullet 2: They “aim to facilitate the efficient dissemination of content.”Bullet 3: OAIshares the objective of supporting access to scholarly materials. Instead of traditional archival materials, OAI serves as a networked repository of scholarly papers. When created, it served as a way to make e-prints, or grey literature, available.Bullet 4: This is their way of saying that they don’t really have technological mechanisms and economic assistance to offer; rather, they offer their framework and their assurance that once the proper technology and standards are created, their organization will adapt its mission and organization to better suit whatever may happen.Bullet 5: “Low-barrier” means that lots of people can use it—it applies to many different institutions and situations. They “believe that exposing metadata is plausible route to such a goal.”
- Bullet 3: Technical experts met to discuss two major interoperability problems: end users were faced with multiple search interfaces making resource discovery harder, and there was no machine-based way of sharing the metadata. They wanted, ideally, to create a universal service for author-archived scholarlyresouces, but decided that the first step would need to be to identify or create interoperable technologies and frameworks for the dissemination of e-prints. They came up with an architecture they called UPS, but quickly changed the name because they didn’t want to be mistaken for the United Parcel Service. With some changes, it became OAI-PMH 1.0.Bullet 4: 1.0 was released in January 2001 and an update (1.1) was released just a few months later, in June 2001. There were some minor updates dealing with the XML. 2.0 was released in 2002 and is not compatible with the earlier versions. Instead of using oai_marc schema, they switched to MARCXML.
- A helpful image from oaforum.org’s tutorial. XML was their standard from the beginning, but notice the changes in the “ABOUT” row. This shows, succinctly, the evolution of what the creators thought OAI-PMH would be used for. As we know, institutional repositories have not received the response that was hoped for, even though some (invested) people still shower it with praise.
- Bullet 1: Not to be understated. In an environment of limited funding and experts, this is invaluable.Bullet 2: Our favorite! Interoperability makes your resources visible to others and thus, metadata from different places can searchable on a single interface. (We’ll play with a single interface soon.) But don’t mistake “CAN” for “ABSOLUTELY DOES.”
- Bullet 1: Data Providers administer systems that support the OAI-PMH as a means of exposing metadata; they do not necessarily offer access to full-text.Service Providers use metadata harvested via the OAI-PMH as a basis for building value-added services; there are no live searches, they only search the metadata that is already there.Bullet 2: Remember, libraries using OAI-PMH are not actually required to register, so this list is wildly incomplete.
- An OAI aggregator is both a Service Provider and a Data Provider. It is a service that gathers metadata records from multiple Data Providers and then makes those records available for gathering by others using the OAI-PMH.
- Bullet 2: Resource is outside the scope of OAI-PMH. It is whatever the metadata is about. Item is “a constituent of a repository from which metadata about a resource can be disseminated. That metadata may be disseminated on-the-fly from the associated resource, cross-walked from some canonical form, actually stored in the repository, etc.” Record is metadata that is in a specific metadata schema.
- Bullet 1: Both identifier and datestamp are required, and nonrepeatable. setSpec is optional and repeatable.
- Bullet 1: There are no recommendations for the implementation of Sets.
- Bullet 2: Harvesters are not required to use each request type, but the repository must allow for each request type. The purpose and parameters of each of these request types are available online, but for the sake of time, I will not explain them individually.
- Bullet 2: It is one of the most used digital resource management tools used in the library world because of the following two advantages.Bullet 3: Which can increase the use of a collection, something that all libraries desire.Bullet 4: And those field names do not need to conform to any standard
- OAI offers guidelines in an online document called “OAI-PMH Implementation Guidelines,” but it hasn’t been updated since 2005.
- *(URI) - URI is the acronym for Universal Resource Identifier. URIs are strings that identify things on the Web. URIs are sometimes informally called URLs (Uniform Resource Locators), although URLs are more limited than URIs. URIs are used in a number of schemes, including the HTTP and FTP URI schemes. Related to Semantic Web.