Interoperability Alison - Introduction & Definition Liane - Methods for Improvement Gary - Challenges
InteroperabilityA Preliminary Definition • To imagine that we can make these metadata schemes communicate with one another, and thus share information, is to imagine that these systems and their metadata can be interoperable.
Purpose of Interoperability • The purpose of interoperability is to make as much content available to as many people and systems (such as computers, different software programs, design interfaces, etc.) who can use it.
Interoperability: • Increases the user base of a resource • Allows different software programs to communicate • Reinforces the ability of a professional community to maintain their own vocabulary (because it does not discourage the use of a specialized vocabulary) • Increases the functionality of metadata structures
Different Levels of Interoperability • Scheme Level • Record Level • Repository Level From Chan, Lois Mai & Marcia Lei Zeng, (2006), “Metadata Interoperability and Standardization--A Study of Methodology, Part 1, D-Lib Magazine 12 (6) http://www.dlib.org/dlib/june06/chan/06chan.html
Scheme Level • Derivation and Modification (MARC into MODS, for example) • Application Profiles (Scheme can be used by community that did not create it) • Crosswalks (Mapping between schemes) http://www.oclc.org/research/projects/mswitch/1_crosswalks.htm
Record Level • If it is not convenient to map at the scheme level, efforts can be made to convert information at the record level. The risk here is loss of data.
Record Level - Example • MARC into MODS http://www.loc.gov/standards/mods
Repository Level • Create a virtual or physical repository to ensure a reliable source of information
Repository Level - Example • Open Archives Initiative (OAI) http://www.openarchives.org/
Repository Level Example • Digital Library for Earth System Education (DLESE) http://www.dlese/org/library/index.jsp
Make lite versions: 15-20 elements. Translate. Create crosswalks. Seek ISO or other domain-specific standardizations. Create templates and examples for users. Facilitate feedback from users. Make schema machine-readable. Anything goes. Ways To Increase Interoperability
While creating metadata, evaluate interoperability: • Unique, one metadata record linked to one resource • Optimally shared, so targeted user groups understand meaning (usual definition) • Stable, persistent through time, so future users understand reason (reason for published standards). • Impossible to make perfect map of anything (Borges), so uncertainty is inevitable. How accept this, minimize it, and work with it?
Interoperability Challenges • How to mediate among different domain vocabularies? • Who decides which one predominates? • Data heterogeneity is one solution, but makes usability more difficult.
Transport Protocol (how metadata is transferred) Content Standard (what data to transfer) Vocabulary (shared meaning of contents) Community defined internationally? By geographical boundaries? By common ethnicity, regardless of spatial location? By shared discourse? By shared present or future goals? Need Community Agreement
Digital Library of India • Digitization of all human knowledge? Part of the Million Book Digital Library Project. • But technological challenges include: Quality Management; Human Errors; Machine Errors; Data Management including Architecture, Preservation, Synchronization, Replication of storage.
Digital Library of IndiaRich Metadata • Regular Metadata - information about book like title, author, publication, etc. • Administrative Metadata - where the book was scanned, original source, etc., information of interest to the operational organization rather than to the end user. • Structural Metadata - information about each page like size and context; improves navigation through the book.
Internationalization Potential • DCMI Localization and Internationalization Working Group, Dublin Core Metadata Initiative • The Java Metadata Interface (JMI) specification “will address the need for a pure java metadata framework API that supports the creation, storage, retrieval, and interchange of metadata.”
Localization in the context of taxonomies--C. Donner • InternationalizationandLocalization. • Internationalization provides only 2 degrees: language & country. • Translator can’t provide local taxonomy. • “The concepts available for simple application localization are insufficient for the localization of complex international content.”
XML to the Rescue? • XML.gov Welcome message: “XML embodies the potential to alleviate many of the interoperability problems associated with the sharing of documents and data.” • DLESE - All metadata interoperability requires Semantics (meaning), Structure (human), Structure (machine, xml), Syntax (grammar) • XML Schema for Metadata Interoperability (XPATH) CONTORSION
ABC Model-metadata utopia? • First presented as a “strawman document” • Combines RDF & XML schemas • Not intended as metadata vocabulary per se, but as a basic model and ontology that provides the notional basis for developing domain, role, or community specific ontologies.
Threefold goals of ABC model • To provide a conceptual basis for understanding and analyzing existing metadata ontologies and instances. • To give guidance to communities beginning to examine and develop descriptive ontologies. • To develop a conceptual basis for automated mapping amongst metadata ontologies. • ABC Metadata Model Constructor pure java RDF based tool