Chapter Eight Interoperability How to Build a Digital Library Ian H. Witten and David Bainbridge

Interoperability Cooperating to provide a universal information service Standards Documents Metadata Queries Protocols

Names URL – Uniform Resource Locator PURL – Persistent URL URN – Universal Resource Name URI – Uniform Resource Identifier

URL Type of URI Useless if resource identifier is unavailable Informal term, no longer used in technical specifications Associated with popular URI schemes: ftp http mailto

PURL Organizational commitment to availability over an extended period of time OCLC

URN Type of URI Includes a naming authority that is able to resolve the URN and provide the named info Intended to serve as a persistent, location-independent resource

URI Generic set of all names or addresses that are short strings referring to resources

Namespaces Help avoid confusion with XML tags that are designed for different purposes Can be used for: XML Documents DTDs XSL Stylesheets Namespace Example: xmlns:xsl = http://www.w3.org/1999/XSL/Transform xmlns:fo = http://www.w3.org/1999/XSL/Format Note: xmlns – qualifier that sets up a namespace

Links Xpointer – a development of Xpath that provides a finer degree of control over part(s) of the document selected Xlink – general way of connecting selected resources Together these provide the foundation for bi-directional links, multi-way links, and annotated links

Links (cont.) Some XLink attributes: Type Href Actuate Show Simple, Extended, Arc, Locator , Resource, Title Href Indicates the resource that the link addresses Actuate Determines when destination resource is accessed onRequest, onLoad Show Determines where destination resource is displayed replace, new, embed

Types XML Schema has extensive facilities for data typing String Boolean Numeric Time

Resource Description Resource Description Framework (RDF) – designed to facilitate the interoperability of metadata. A way of modeling anything that can be represented as a URI Resources described in a compositional framework Serialization via XML

Collection Level Metadata Structured info about the entire collection Coverage Number of documents Access conditions Collection Understanding Coming to an understanding of the contents of a collection by inspecting individual artifacts, metadata filtering and interactive information visualization

Open eBook Open eBook Forum – association of hardware and software companies, publishers, authors, users, and related organizations whose goal is to establish common specifications for eBook systems that will benefit content creators, manufactures, and consumers Open eBook uses XML namespaces, document type definitions, cascading style sheets, subset of HTML 4.0/XHTML, Dublin Core, Unicode and a set of MIME types

Open eBook (cont.) Each publication takes the form of a package file with extension .opf Unique publication identity Metadata Manifest list of supporting files Spine – linear reading order for files Tours – permit different traversal patterns through material Guide – structural elements, such as a title page or table of contents

Query Language Common Command Language (CCL) (Z39.58) Defines an information retrieval cycle that is independent of the software used Contains commands Starting a session Choosing collections Finding items in collections Sorting results Displaying items Printing items Reviewing previous queries Stopping a session

XML Query Xquery Queries are used to construct new XML documents from existing XML document collections Build upon XPath and XML Schema Contains its own functional programming language Data model Forests of trees

Protocols Z39.50 OAI Dienst SDLIP