1. 1 New Standards on the Web Brian KellyEmail Address UK Web Focus B.Kelly@ukoln.ac.uk UKOLNURL 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 Deployment Issues Aims of Talk To give brief overview of web architecture To describe developments to web standards (especially those relevant to library community) To briefly address implementation models Due to lack of time, talk will not cover some new standards, such as: Graphics Multimedia e-commerce Aims of Talk To give brief overview of web architecture To describe developments to web standards (especially those relevant to library community) To briefly address implementation models Due to lack of time, talk will not cover some new standards, such as: Graphics Multimedia e-commerce

3. 3 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, PDF) 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++ HTML extensions PDF and Java? HTML extensions PDF and Java?

4. 4 The Web Vision Tim Berners-Lee's vision for the Web: Evolvability is critical 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 See keynote talk at WWW 7 conference at

5. 5 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 - W3C-Rec Improved forms Hooks for stylesheets Hooks for scripting languages Table enhancements Better printing CSS 2.0 - W3C-Rec Support for all HTML formatting Positioning of HTML elements Multiple media support Problems Changes during CSS development Netscape & IE incompatibilities Continued use of browsers with known bugs Problems Changes during CSS development Netscape & IE incompatibilities Continued use of browsers with known bugs DOM - W3C-Rec Document Object Model Hooks for scripting languages Permits changes to HTML & CSS properties and content

6. 6 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

7. 7 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.) HTML is being described in HTML - see

8. 8 XML Support XML support: Can be provided at backend (Partial) XML support in IE 5 Also in Netscape 5? XML document with no style sheet - XML tree displayed XML document with style sheet http://www.xml.com/1999/03/ie5/first-x.xml

9. 9 XLink, XPointer and XSL XLink will provide sophisticated hyperlinking missing in HTML: Links that lead user to multiple destinations Bidirectional links Links with special behaviours: –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

10. 10 Addressing URLs have limitations: Lack of long-term persistency –Organisation changes name –Department shut down or merged –Directory structure reorganised Inability to support multiple versions of resources (mirroring) Solutions: Unique identifiers possible, but resolution difficult Solutions include DOIs, PURLs, etc. "URLs don’t' break - people break them". Think about URL persistency and naming guidelines

11. 11 Transport HTTP/0.9 and HTTP/1.0:  Design flaws and implementation problems HTTP/1.1: Addresses some of these problems 60% server support Performance benefits! (60% packet traffic reduction)  Is acting as fire-fighter  Not sufficiently flexible or extensible HTTP/NG: Radical redesign using object-oriented technologies Undergoing trials Gradual transition (using proxies) Integration of application (distributed searching?)

12. 12 Metadata Metadata - the missing architectural component from the initial implementation of the web Metadata - RDF 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

13. 13 Metadata Examples DSig (Digital Signatures initiative): Key component for providing trust on the web 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 P3P (Platform for Privacy Preferences): Developing methods for exchanging Privacy Practices of Web sites and user Note that discussions about additional rights management metadata are currently taking place

14. 14 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

15. 15 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 23-Mar-99 ValidUntil RDF Data Model page.html £0.05 23-Mar-99 Property Cost InstanceOf ValidUntil Value PropObj Cost PropName

16. 16 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/

17. 17 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  RDF Schemas describe the meaning of each property name  Signed RDF is the basis for trust

18. 18 Deployment Issues How can new technologies be deployed? Expect (hope) everyone will move to new browsers Use technologies in backwards- compatible manner Develop additional protocols e.g. –Transparent Content Negotiation –CC/PP User-Agent Negotiation Use of proxy intermediaries

19. 19 Intermediaries can provide functionality not available at client: DOI support XML support / format conversion Authentication Intermediaries can provide functionality not available at client: DOI support XML support / format conversion Authentication 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

20. 20 Conclusions To conclude: Standards are important, especially for national initiatives and other large-scale services 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 Metadata is big growth area Intermediaries may have a role to play in deploying standards-based solutions Intelligent servers likely to be important