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

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

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

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

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

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

URI Generic set of all names or addresses that are short strings referring to resources 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 Help avoid confusion with XML tags that are designed for different purposes Can be used for: Can be used for: XML Documents XML Documents DTDs DTDs XSL Stylesheets XSL Stylesheets Namespace Example: xmlns:xsl = xmlns:xsl = xmlns:fo = xmlns:fo = 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 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 Xlink – general way of connecting selected resources Together these provide the foundation for bi- directional links, multi-way links, and annotated links Together these provide the foundation for bi- directional links, multi-way links, and annotated links

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

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

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

Collection Level Metadata Structured info about the entire collection Structured info about the entire collection Coverage Coverage Number of documents Number of documents Access conditions Access conditions Collection Understanding Collection Understanding Coming to an understanding of the contents of a collection by inspecting individual artifacts, metadata filtering and interactive information visualization 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 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 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 Each publication takes the form of a package file with extension.opf Unique publication identity Unique publication identity Metadata Metadata Manifest list of supporting files Manifest list of supporting files Spine – linear reading order for files Spine – linear reading order for files Tours – permit different traversal patterns through material Tours – permit different traversal patterns through material Guide – structural elements, such as a title page or table of contents Guide – structural elements, such as a title page or table of contents

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

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

Protocols Z39.50 Z39.50 OAI OAI Dienst Dienst SDLIP SDLIP