1. 1 Standards, the Web and eLib Projects Brian KellyEmail Address UK Web Focus B.Kelly@ukoln.ac.uk UKOLN University of Bath http://www.ukoln.ac.uk/ UKOLN is funded by the British Library Research and Innovation Centre, the Joint Information Systems Committee of the Higher Education Funding Councils, as well as by project funding from the JISC’s Electronic Libraries Programme and the European Union. UKOLN also receives support from the University of Bath where it is based.

2. 2 Contents Introduction Web Standards Overview Web Standards: Data Formats Transport Addressing Metadata Accessibility Programming Languages Distributed Searching Deployment Issues Questions Aims of Talk To review key web standards To describe standards bodies To identify opportunity for involvement To briefly address implementation models Aims of Talk To review key web standards To describe standards bodies To identify opportunity for involvement To briefly address implementation models

3. 3 UK Web Focus / W3C UK Web Focus: JISC funded post based at UKOLN (Bath Univ) Advises UK HE community on web issues Represents JISC on W3C W3C ( World Wide Web Consortium ): International consortium, with headquarters at MIT, INRIA and Keio University (Japan) Coordinates development of web protocols Four domains: Architecture Technology & Society User Interface Web Accessibility

4. 4 Standardisation W3C Produces W3C Recommendations on Web protocols Managed approach to developments Protocols initially developed by W3C members Decisions made by W3C, influenced by member and public review IETF Produces Internet Drafts on Internet protocols Bottom-up approach to developments Protocols developed by interested individuals "Rough consensus and working code" ISO Produces ISO Standards Can be slow moving and bureaucratic Produce robust standards Proprietary De facto standards Often initially appealing (cf PowerPoint) May emerge as standards PNG HTML Z39.50 Java? PNG HTML Z39.50 Java? PNG HTML HTTP PNG HTML HTTP URN whois++ HTTP URN whois++ Note JISC Standards Subcommitee HTML extensions PDF and Java? HTML extensions PDF and Java?

5. 5 The Web Vision Tim Berners-Lee's vision for the Web: Automation of information management: If a decision can be made by machine, it should All structured data formats should be based on XML Migrate HTML to XML All logical assertions to map onto RDF model All metadata to use RDF

6. 6 Standards Need for standards to provide: Platform independence Application independence Avoidance of patented technologies Flexibility ("evolvability" - Tim Berners-Lee) Architectural integrity Long-term access to data Ideally look at standards first, then find applications which support the standards Difficult to achieve this ideal!

7. 7 Web Protocols Web initially based on three simple protocols: Data Formats HTML (HyperText Markup Language) provides the data format for native documents Addressing URLs (Uniform Resource Locator) provides an addressing mechanism for web resources Transport HTTP (HyperText Transfer Protocol) defines transfer of resources between client and server Data Format HTML Addressing URL Transport HTTP

8. 8 HTML History HTML 1.0Unpublished specification. DTD developed by Tim Berners-Lee (CERN). HTML 2.0Spec. based on innovations from NCSA (forms and inline images!) HTML 3.0Proposed spec. (renamed from HTML+). Very comprehensive Failed to complete IETF standardisation Little implementation experience ProprietaryIntroduction of proprietary HTML elements by Netscape and Microsoft HTML 3.2Spec. based on description of mainstream innovations in marketplace HTML 4.0Current recommendation

9. 9 Problems with Extensions Device Dependency Resources are dependent on a particular browser Platform dependency Costs Potential costs in re-engineering Architecture Proprietary innovations have been flawed: –Merging content and appearance –Maintenance of resources Accessibility problems: –Poor support for access by disabled But: Experiments are needed

10. 10 HTML 4.0, CSS 2.0 and DOM HTML 4.0 used in conjunction with CSS 2.0 (Cascading Style Sheets) and the DOM provides an architecturally pure, yet functionally rich environment HTML 4.0 Improved forms Hooks for stylesheets Hooks for scripting languages Table enhancements Better printing CSS 2.0 Support for all HTML formatting Positioning of HTML elements Multiple media support CSS Problems Changes during CSS development Netscape & IE incompatibilities Continued use of browsers with known bugs CSS Problems Changes during CSS development Netscape & IE incompatibilities Continued use of browsers with known bugs DOM Document Object Model Hooks for scripting languages Permits changes to HTML & CSS properties and content

11. 11 HTML Limitations HTML 4.0 / CSS 2.0 have limitations: Difficulties in introducing new elements –Time-consuming standardisation process ( ) –Dictated by browser vendor (, ) Area may be inappropriate for standarisation: –Covers specialist area (maths, music,...) –Application-specific ( ) HTML is a display (output) format HTML's lack of arbitrary structure limits functionality: –Find all memos copied to John Smith –How many unique tracks on Jackson Browne CDs

12. 12 XML XML: Extensible Markup Language A lightweight SGML designed for network use Addresses HTML's lack of evolvability Arbitrary elements can be defined (,, etc) Agreement achieved quickly - XML 1.0 became W3C Recommendation in Feb 1998 Support from industry (SGML vendors, Microsoft, etc.) Support in Netscape 5 and IE 5

13. 13 XML Concepts Well-formed XML resources: Make end-tags explicit:... Make empty elements explicit: Quote attributes <IMG SRC="logo" HEIGHT="20" Use consistent upper/lower case Valid XML resources: Need DTD XML Namespaces: Mechanism for ensuring unique XML elements : Insert M-471

14. 14 XML Deployment Ariadne issue 14 has article on "What Is XML?" Describes how XML support can be provided: Natively by new browsers Back end conversion of XML - HTML Client-side conversion of XML - HTML / CSS Java rendering of XML Examples of intermediaries See http://www.ariadne.ac.uk/issue15/what-is/

15. 15 XLink, XPointer and XSL XLink will provide sophisticated hyperlinking missing in HTML: Links that lead user to multiple destinations Bidirectional links Links with special behaviors: –Expand-in-place / Replace / Create new window –Link on load / Link on user action Link databases XPointer will provide access to arbitrary portions of XML resource XSL stylesheet language will provide extensibility and transformation facilities (e.g. create a table of contents) England France

16. 16 Adobe PDF Adobe PDF:  Proprietary format Provides control over document appearance (originally lacking in HTML)  Lack of support for document structure  Requires proprietary (though free) plugin (Acrobat) Proprietary plugin provides richer functionality (e.g. suppress printing) Development work on improved hyperlinking Becoming more open? Conclusion Acceptable output format? NOTE PDF is not a W3C activity NOTE PDF is not a W3C activity

17. 17 Addressing URLs (e.g. http://www.bristol-poly.ac.uk/depts/music/ ) have limitations: Lack of long-term persistency –Organisation changes name –Department scrapped –Directory structure reorganised Inability to support multiple versions of resources (mirroring) URNs (Uniform Resource Names): Proposed as solution Difficult to implement (no W3C activity in this area)

18. 18 Addressing - Solutions DOIs (Document Object Identifiers): Proposed by publishing industry as a solution Aimed at supporting rights ownership Business model needed PURLs (Persistent URLs): Provide single level of redirection Cache support: National caches could provide simple URN support For further information see:

19. 19 Transport HTTP/0.9 and HTTP/1.0: Made the Web popular  Design flaws and implementation problems caused poor performance HTTP/1.1: Addresses some of these problems 60% server support, client & proxy support beginning Performance benefits! (optimised implementation reduces packet traffic by 2/3)  Is acting as fire-fighter  Poor usage counting  Not sufficiently flexible or extensible

20. 20 HTTP/NG HTTP/NG: Two W3C Working Groups: Web Characterisations: Study Web usage and form requirements New log format for easier collection & anonymisation Protocol Design: Redesign Web as distributed object application Transition to HTTP/NG will be gradual –Use of proxies / HTTP/1.1 UPGRADE header –Layer HTTP/NG on top of HTTP/NG using POST Distributed searching as HTTP/NG application? W3C Briefing Package due out on 7 July

21. 21 Metadata Metadata - the missing architectural component from the initial implementation of the web Metadata PICS, TCN, MCF, DSig, DC,... Addressing URL Data format HTML Transport HTTP Metadata Needs: Resource discovery Content filtering Authentication Improved navigation Multiple format support Rights management Metadata Needs: Resource discovery Content filtering Authentication Improved navigation Multiple format support Rights management

22. 22 Privacy P3P (Platform for Privacy Preferences): Example of a metadata application Privacy concerns are a current barrier to Web development (esp. in US) P3P project developing methods for exchanging Privacy Practices of Web sites and user Documents on architecture and vocabulary available P3P1.0 draft spec released on 19 May 1998 See Relevant to Jun 98 lis-elib discussion

23. 23 Digital Signatures DSig ( Digital Signatures initiative ): Key component for providing trust on the web DSig 1.0 is based on PICS DSig 2.0 will be based on RDF and will support signed assertion: –This page is from the University of Bath –This page is a legally-binding list of courses provided by the University Potential for use in authentication but: –Little activity in this area in W3C –Implementation would require expensive infrastructure

24. 24 RDF RDF (Resource Description Framework): Highlight of WWW 7 conference Provides a metadata framework ("machine understandable metadata for the web") Based on ideas from content rating (PICS), resource discovery (Dublin Core) and site mapping (MCF) Applications include: –cataloging resources– resource discovery –electronic commerce– intelligent agents –digital signatures– content rating –intellectual property rights– privacy See

25. 25 RDF Model RDF: Based on a formal data model (direct label graphs) Syntax for interchange of data Schema model Resource Value PropertyType Property page.html £0.05 Cost 11-May-98 ValidUntil RDF Data Model page.html £0.05 11-May-98 Property Cost InstanceOf ValidUntil Value PropObj Cost PropName

26. 26 RDF Example Example of Dublin Core metadata in RDF John Smith John’s Home Page

27. 27 Browser Support for RDF Mozilla (Netscape's source code release) provides support for RDF. Mozilla supports site maps in RDF, as well as bookmarks and history lists See Netscape's or HotWired home page for a link to the RDF file. Trusted 3rd Party Metadata Embedded Metadata e.g. sitemaps Image from http://purl.oclc.org/net/eric/talks/www7/devday/

28. 28 RDF Conclusion  RDF is a general-purpose framework  RDF provides structured, machine- understandable metadata for the Web  Metadata vocabularies can be developed without central coordination  Role for eLib projects in defining schemas?  RDF Schemas describe the meaning of each property name  Signed RDF is the basis for trust

29. 29 Languages Java Powerful platform independent object-oriented system with: Language Java Virtual Machine Chip OS Owned by Sun but being standardised by ISO Beware Microsoft Java DK "This is the year the performance problem is solved" See ECMAScript Standardised version of JavaScript Important role in DHTML, DOM, XSL,... See

30. 30 WAI WAI (Web Accessibility Initiative): Ensures web specs address accessibility issues Based on universal design principles Authoring: Page Author Accessibility Checklist and Guidelines draft at Software WAI Accessibility Guidelines: User Agent draft at Note JISC DISinHE project at Dundee University. See

31. 31 Distributed Searching Distributed searching important for the DNER (Distributed National Electronic Resource) ROADS prototype provides cross-searching using whois++ http://prospero.ahds.ac.uk:8080/ahds_live/ AHDS prototype provides cross-searching using Z39.50

32. 32 Distributed Searching Issues Providing access to resources by software rather than by humans raises several issues: Loss of visibility of service / value-added web services Possible performance problems Information overload Finding the service Solutions: Giving visibility and pointers in results sets Service metadata: –Service only available for cross-searching by non AC.UK users outside peak hours –Service covers UK Census data Need for agreed metadata standards (profiles, rights issues, …)

33. 33 Intermediaries can provide functionality not available at client: DOI support XML support Format conversion Intermediaries can provide functionality not available at client: DOI support XML support Format conversion Deployment Issues More sophisticated deployment techniques can be adopted to overcome deficiencies in simple model HTML resource browser Web server Web server simply sends file to client File contains redundant information (for old browsers) plus client interrogation support HTML / XML / database resource browser Server proxy Client proxy Original Model Sophisticated Model Intelligent Web server Example of an intermediary

34. 34 Conclusions To conclude: Standards are important, especially for national initiatives, such as eLib Proprietary solutions are often tempting because: –They are available –They are often well-marketed and well-supported –They may become standardised –Solutions based on standards may not be properly supported by applications Intermediaries may have a role to play in deploying standards-based solutions Opportunity for involvement with standards bodies (e.g. W3C Working Groups)

35. 35 Question Time Any questions?