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![A centre of expertise in digital information management
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Content Management
Storing resources in HTML and GIF/JPEG is:
Easy to do and is a low cost solution
Makes reuse and management of resources difficult
GIF /
JPEG
XML
TIFF /
….
On-the-fly
or batch
conversion
WML
HTML
User-agent
Negotiation
Content Management System for:
• Management of content (content maintenance, metadata
management, access rights, project management, …)
• Delivery of content (e.g. user-agent negotiation, alternative file
formats [such as WML], etc.))](https://image.slidesharecdn.com/iwmw2002webstandards-briefing-c2-160307191510/85/IWMW-2002-Web-standards-briefing-session-C2-51-320.jpg)
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IWMW 2002: Web standards briefing (session C2)
The document presents a comprehensive overview of web architecture and standards, emphasizing the importance of standards in higher education and further education for ensuring accessibility, resource reusability, and preservation. It addresses various web standards such as W3C, XML, and HTML, highlighting their roles in facilitating web functionality and interoperability while cautioning against proprietary solutions. Additionally, it discusses metadata's significance in enhancing resource discovery, navigation, and rights management in the digital environment.
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IWMW 2002: Web standards briefing (session C2)
- 1. A centre ofexpertise in digital information management Web Standards Briefing Brian Kelly UKOLN University of Bath Bath, BA2 7AY Email B.Kelly@ukoln.ac.uk URL http://www.ukoln.ac.uk/ UKOLN is supported by:
- 2. A centre ofexpertise in digital information management 2 Contents • Introduction • Standards • The Original Web Architecture • Architectural Developments • Deployment Issues • Discussion Aims of Talk • To give brief overview of Web architecture • To describe developments to Web standards • To briefly address implementation models Aims of Talk • To give brief overview of Web architecture • To describe developments to Web standards • To briefly address implementation models Please feel free to ask questions at any time, especially to clarify any unexplained TLAs or XTLAs Please feel free to ask questions at any time, especially to clarify any unexplained TLAs or XTLAs
- 3. A centre ofexpertise in digital information management 3 About Me Brian Kelly: • UK Web Focus – a JISC-funded post to advise HE and FE communities on Web developments • Based in UKOLN - a national focus of expertise in digital information management based at the University of Bath • Involved in Web since 1993, while working in the Computing Service at University of Leeds • Represent JISC on the World Wide Web Consortium (W3C)
- 4. A centre ofexpertise in digital information management 4 Standards in HE/FE Context Standards are important in the HE and FE sector to: • Ensure widespread access to resources • Enables resources to be reused and repurposed • Ensure scholarly resources can be preserved • Address accountability of public funding • Minimise resource costs for upgrading systems • Provide universal access to resources (cf disability legislation)
- 5. A centre ofexpertise in digital information management 5 Standards Need for standards to provide: • Platform and application independence • Avoidance of patented technologies • Flexibility and architectural integrity • Long-term access to data Ideally look at standards first, then find applications which support the standards. However it can be difficult to achieve this ideal! Before the Web Access to resources typically required use of software vendor’s software – which was only available on limited no. of platforms. Often the software would be licensed. The goal of the Web was to provide universal access to resources. Who could argue with this goal? Before the Web Access to resources typically required use of software vendor’s software – which was only available on limited no. of platforms. Often the software would be licensed. The goal of the Web was to provide universal access to resources. Who could argue with this goal?
- 6. A centre ofexpertise in digital information management 6 Standards and the Web W3C • Produces W3C Recommendations on Web protocols • Managed approach to developments • Protocols initially developed by W3C members • Decisions made by W3C, informed by member & public review IETF • Produces Internet Drafts on Internet protocols • Bottom-up approach to developments • Protocols may be 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 HTML, XML, PNG, …HTML, XML, PNG, … HTTP URN whois++ HTTP URN whois++ HTML extensions PDF and Java? HTML extensions PDF and Java?
- 7. A centre ofexpertise in digital information management 7 The Case For W3C Standards Why use open standards developed by the W3C? Why not leave it to the marketplace? W3C’s open standards have been developed in an open environment, with the aim of achieving platform and application independency Commercial companies develop proprietary formats in order to maximise their profits and dividends to shareholders W3C’s open standards have been developed to interoperate with each other according to W3C’s design vision Commercial companies typically develop proprietary formats in isolation, or along the lines of a company vision
- 8. A centre ofexpertise in digital information management 8 Standards, Architectures, Applications, Resources This talk touches on several areas Architectures: models for implementing systems Architectures: models for implementing systems Standards: concerned with protocols and file formats Standards: concerned with protocols and file formats Open standards vs. Proprietary HTML / XML vs. PDF CSS / XSL vs. HTML GIF vs PNG Which standards are applicable NT / Unix File system / database application HTML tools / content management Apache / IIS FrontPage / Dreamweaver Oracle / SQLServer ColdFusion vs ASP Development vs. Migration costs Use of in-house expertise In-house vs. out-sourced Licensed vs. open source Resources: financial and staff costs needed to implement systems Resources: financial and staff costs needed to implement systems Applications: software products used to implement systems Applications: software products used to implement systems
- 9. A centre ofexpertise in digital information management 9 GIF As an example of the dangers of use of proprietary solutions, consider the GIF file format: • Unisys announce that they hold patent to compression algorithm used in GIF images and users of GIF will have to pay • Following much debate, Unisys require payment for licence from software developers - and also for end users of unlicensed software ($5,000!) • Web community responds with PNG format • See <http://burnallgifs.org/> WARNING: • There is no guarantee that payment will not be required for proprietary file formats which are currently free
- 10. A centre ofexpertise in digital information management 10 How Does The Web Work? The Web has three fundamental concepts: • URLs: addresses of resources • HTTP: dialogue between client and server • HTML: format of resources The Netsoft home page 1 User clicks on link to the address (URL) http://www.netsoft.com/hello.html 2 Browser converts link to HTTP command (METHOD): Connect to computer at www.netsoft.com GET /hello.html 3 Remote computer sends file Welcome to Netsoft 4 Local computer displays HTML file Web Browser Web server <HTML> <TITLE>Welcome</TITLE>.. <P>The <A HREF=“…”> Netsoft</A> home page</P>
- 11. A centre ofexpertise in digital information management 11 Approaches To HTML Emphasis on managing HTML resources inappropriate: • HTML is an output format, which cannot easily be reused (e.g. WAP, e-Books, etc.) • Need to manage HTML fragments (only partly achievable with SSIs) • Need to manage collections of resources • Need to have single master source of data • Need to support new developments such as personalisation • Difficult to integrate with new formats Issues • Should we stop giving HTML courses? • Should we stop buying HTML authoring tools? Issues • Should we stop giving HTML courses? • Should we stop buying HTML authoring tools?
- 12. A centre ofexpertise in digital information management 12 XML XML: • Extensible Markup Language • A lightweight SGML designed for network use • Addresses HTML's lack of evolvability • Arbitrary elements can be defined (<STUDENT- NUMBER>, <PART-NO>, etc) • Agreement achieved quickly - XML 1.0 became W3C Recommendation in Feb 1998 • Support from industry (SGML vendors, Microsoft, etc.) • Support in latest versions of Web browsers
- 13. A centre ofexpertise in digital information management 13 XML Concepts (1) Well-formed XML resources: Make end-tags explicit: <li>...</li> Make empty elements explicit: <img ... /> Quote attributes <img src="logo.gif" height="20" Use consistent upper/lower case <p> and <P> are different XML Namespaces: Mechanism for ensuring unique XML elements: <?xml:namespace ns="http://foo.org/ 1998-001" prefix="i"> <p>Insert <i:PART>M-471</i:PART></p>
- 14. A centre ofexpertise in digital information management 14 XML Concepts (2) XML Schemas • Allow constraints to be applied on XML attributes • Express shared vocabularies and allow machines to carry out rules made by people • Richer than DTDs • See <http://www.w3.org/XML/Schema> XSLT • A language for transforming XML from one DTD to another, or to another format (e.g. PDF) • Written in XML • Knows about XML (e.g. tree structures, etc.) • See <http://www.xslt.com/>
- 15. A centre ofexpertise in digital information management 15 XML Concepts (3) XLink provides sophisticated hyperlinking: • Links that allow you to choose multiple destinations • Bidirectional links • Links with special behaviours: • Expand-in-place / Replace / Create new window • Link on load / Link on user action • Link databases • See <http://www.xml.com/pub/a/2000/09/xlink/> XPointer • Provides access to arbitrary portions of XML resource • See <http://www.devshed.com/ Server_Side/XML/XPointer/page1.html> England France
- 16. A centre ofexpertise in digital information management 16 Getting to XML With XHTML XHTML: • HTML represented in XML • Some small changes to HTML: Elements in lowercase <p> not <P> Attributes must be quoted <img src="logo" height="50"> Elements must be closed: < p >... </ p >) <img src="logo" ... /> • Gain benefits from XML • Tools available (e.g. HTML-Kit from http://www.chami.com/html-kit/) • See <http://www.webreference.com/xml/ column6/>, <http://groups.yahoo.com/ group/XHTML-L/> and <http://www.ariadne.ac.uk/ issue27/web-focus/> Note the IWMW 2002 Web site is (mostly) XHTMLNote the IWMW 2002 Web site is (mostly) XHTML
- 17. A centre ofexpertise in digital information management 17 CSS CSS: • Cascading Style Sheets • XHTML/XML defines structure, CSS describes the appearance • CSS 1.0 and 2.0 now W3C recommendations • CSS 3.0 in preparation (modularised) • We should be using CSS: Part of architecture Ease of maintenance Becoming much richer Accessibility • See <http://www.w3c.org/Style/CSS/>
- 18. A centre ofexpertise in digital information management 18 SVG SVG: • Scalable Vector Graphics • A language for describing two-dimensional graphics in XML • See <http://www.w3.org/Graphics/SVG/ Overview.htm8> • Also see presentation on XML written in SVG at <http://www.w3c.org/Talks/2001/12/ IH-Euroweb/W3CInTheWorldslide.svgz> • WWW 2002 talk at <http://www.w3c.org/2002/Talks/ www2002-SVG/>
- 19. A centre ofexpertise in digital information management 19
- 20. A centre ofexpertise in digital information management 20 SVG Example http://www.karto.ethz.ch/neumann/cartography/vienna/http://www.karto.ethz.ch/neumann/cartography/vienna/
- 21. A centre ofexpertise in digital information management 21 SVG and XSLT This example: • Originally written in Java • Author realised that XSLT would be easier • Uses SVG for chess board and pieces • Uses XSLT to move pieces http://people.w3.org/maxf/ChessGML/http://people.w3.org/maxf/ChessGML/
- 22. A centre ofexpertise in digital information management 22 CML, SVG and XSLT http://www.adobe.com/svg/demos/cml2svg/html/index.htmlhttp://www.adobe.com/svg/demos/cml2svg/html/index.html A molecule described in CML can be transformed using XSLT into SVG, allowing it to be displayed and manipulated A molecule described in CML can be transformed using XSLT into SVG, allowing it to be displayed and manipulated
- 23. A centre ofexpertise in digital information management 23 SMIL SMIL: • Synchronized Multimedia Integration Language • A language for authoring of interactive audiovisual presentations • Allows you to synchronize text, images, audio and video in a document • An XML Application • See <http://www.w3c.org/AudioVideo/>
- 24. A centre ofexpertise in digital information management 24 SMIL Example http://www.kevlindev.com/tutorials/ basics/animation/svg_smil/index.htm http://www.kevlindev.com/tutorials/ basics/animation/svg_smil/index.htm http://www.reseau.it/smil/smilapp_en.htmlhttp://www.reseau.it/smil/smilapp_en.html
- 25. A centre ofexpertise in digital information management 25 MathML MathML: • An XML application for maths • Various plugins, dedicated readers, etc. • Mozilla renders natively See <http://www.mozilla.org/projects/mathml/>See <http://www.mozilla.org/projects/mathml/>
- 26. A centre ofexpertise in digital information management 26 Modularisation How can you: • Include XML resources such as MathML, ChemML, etc in XHTML documents? • Provide a subset of XHTML features in browsers on devices such as mobile phones, PDAs, etc.? The answer is: • XHTML modularisation (modularization ) • See <http://www.w3.org/TR/xhtml-modularization/> and <http://www.xml.com/pub/a/2002/01/16/ xhtml-m12n.html>
- 27. A centre ofexpertise in digital information management 27 Addressing (1) URLs have limitations: • Lack of long-term persistency Univ. changes name or department shut down or merged Directory structure reorganised • Inability to support multiple versions (mirroring) URIs: • Were an address of a resource – and moving a resource was annoying but not critical • With the development of “Web services”, structured resources, B2B communications, etc. the availability of URIs will be of great importance
- 28. A centre ofexpertise in digital information management 28 Addressing (2) Solutions: • Unique identifiers possible, but resolution difficult • Solutions include DOIs, PURLs, OpenURLs, etc. • Interest mostly in publishing sector • "URIs don’t break - people break them" • Think about URL persistency & naming guidelines: <http://www.ariadne.ac.uk/issue31/ web-focus/>
- 29. A centre ofexpertise in digital information management 29 Transport - The Original Roadmap 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)
- 30. A centre ofexpertise in digital information management 30 Transport - Today Today: • Responsibility for development moved from W3C to IETF • Little progress with HTTP/NG • Problems with HTTP/1.1: Lengthy (176-page) specification without much explicit rationale for design decisions Environment has become more complex Lack of a clean underlying data model … • See “Clarifying the Fundamentals of HTTP” <http://www2002.org/CDROM/refereed/444/>
- 31. A centre ofexpertise in digital information management 31 SOAP SOAP: • Simple Object Access Protocol • Facilitates development of machine-to-machine communications using Web protocols by providing a richer XML-based messaging mechanism • A protocol for invoking methods on servers, services, components and objects • Codifies existing practice of using XML and HTTP as a method invocation mechanism • See FAQ at <http://www.develop.com/soap/ soapfaq.htm>
- 32. A centre ofexpertise in digital information management 32 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
- 33. A centre ofexpertise in digital information management 33 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
- 34. A centre ofexpertise in digital information management 34 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 <URL: http://www.w3.org/ Talks/1998/0417-WWW7-RDF>
- 35. A centre ofexpertise in digital information management 35 RDF Model RDF: • Based on a formal data model (direct label graphs) • Syntax for interchange of data • Schema model Resource ValuePropertyType Property page.html £0.05Cost 23-Mar-99 ValidUntil RDF Data Model page.html £0.05 23-Mar-99 Property Cost InstanceOf ValidUntil Value PropObj Cost PropName
- 36. A centre ofexpertise in digital information management 36 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/Image from http://purl.oclc.org/net/eric/talks/www7/devday/
- 37. A centre ofexpertise in digital information management 37 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 But: • Is it too complex? • Is it the right approach? But: • Is it too complex? • Is it the right approach?
- 38. A centre ofexpertise in digital information management 38 RSS – An XML/RDF Application RSS (Rich / RDF Site Summary): • Initially XML, now an RDF application • Used for news feeds • Lightweight approach that we should be investigating (e.g. see news page on IWMW 2002 Web site) See example of an RSS authoring tool and parser at <http://rssxpress.ukoln.ac.uk/> See example of an RSS authoring tool and parser at <http://rssxpress.ukoln.ac.uk/>
- 39. A centre ofexpertise in digital information management 39 Model For News Feeds Good For User The end user can choose her news feeds, including local news, news from JISC services and news from third parties Good For Service The service can chose its own information flow model. Its news is disseminated automatically. Good For User The end user can choose her news feeds, including local news, news from JISC services and news from third parties Good For Service The service can chose its own information flow model. Its news is disseminated automatically. RSS Institution (e.g. Bath) RSSCommunity (e.g. MIDAS) RSS External (e.g. BBC) Local News .. JISC News .. National News XHTML converted to RSS Structured database converted to RSS Zope CMS outputs to RSS & XHTML
- 40. A centre ofexpertise in digital information management 40 What About Tomorrow? Two interesting areas: The Semantic Web • Will allow intelligent agents to know about resources • AI and ontologists meet the Web • Uses RDF (Resource Description Framework) – W3C’s framework for metadata • Some concerns over scale of problem • See <http://www.w3.org/2001/sw/> Web Services • Highlight of the WWW 10 and WWW 2002 conferences
- 41. A centre ofexpertise in digital information management 41 Web Services The Web: • Initially used for viewing static resources • Then interactive services built (e.g. e-learning) We now want: • Programmable Web services which can be used by other Web services using standards Web protocols We have experience of the first generation of externally-hosted Web services (stats services, voting systems, etc.) - see <http://www.ariadne.ac.uk/issue23/web-focus/>. The next generation will be programmable and machine- understandable Note that concerns over outsourcing may be an issue We have experience of the first generation of externally-hosted Web services (stats services, voting systems, etc.) - see <http://www.ariadne.ac.uk/issue23/web-focus/>. The next generation will be programmable and machine- understandable Note that concerns over outsourcing may be an issue
- 42. A centre ofexpertise in digital information management 42 Example Some examples at gotdotnet.com: • Mailsender • Thumbnail Generator Concepts been around for some time (see Auditing & Evaluating Web Sites workshop) Now being standardised (UDDI, WSDL, SOAP, …) http://www.gotdotnet.com/playground/ services/thumbnailgen.aspx http://www.gotdotnet.com/playground/ services/thumbnailgen.aspx
- 43. A centre ofexpertise in digital information management 43 We’ve Been Here Before Reusable components available on the network: • Sounds like COM/DCOM, CORBA, etc. for reusable program components Network services for use within a community: • Sounds like JISCmail, RDN, EDINA, MIMAS, BIDS, Mirror Service and other JISC Services • It’s outsourcing – but it’s OK! Web Services And UK HE / FE Communities Sounds like a great idea: • We’ve the organisational framework to develop national services (JISC, etc.) • We’ve got the network • We’ve a community which is willing to exploit centrally-provided services and wants to avoid reinventing the wheel (haven’t we?) Web Services And UK HE / FE Communities Sounds like a great idea: • We’ve the organisational framework to develop national services (JISC, etc.) • We’ve got the network • We’ve a community which is willing to exploit centrally-provided services and wants to avoid reinventing the wheel (haven’t we?)
- 44. A centre ofexpertise in digital information management 44 Currently... End user Local content National content International content Web Web Web Web Web Web We should be moving away from providing separate Web services with their own interfaces … We should be moving away from providing separate Web services with their own interfaces …
- 45. A centre ofexpertise in digital information management 45 Currently... End user Collection Description (e.g. Agora) User Profile (e.g. Headline) Authentication (Athens) Local content National content International content Web Web Web Web Web Web … and separate metadata repositories and access services (which are sometimes centralised) … … and separate metadata repositories and access services (which are sometimes centralised) … Agora and headline are eLib Hybrid libraries
- 46. A centre ofexpertise in digital information management 46 Future... Content End user User profile Collection description Authentication Metadata Services / Access (Web) Services Application Services? Bookmarks Spell- checker .. and move to Web-accessible, machine-understandable Web services as well as seamless access to content .. and move to Web-accessible, machine-understandable Web services as well as seamless access to content Brokered access provide by institutional portal (MLE, …)
- 47. A centre ofexpertise in digital information management 47 Other W3C Areas See • W3C site map at <http://www.w3c.org/Help/siteindex> • TimBL’s Web Design Issues at <http://www.w3c.org/DesignIssues> • Web Architecture from 50,000 feet at <http://www.w3.org/DesignIssues/Architecture.html>
- 48. A centre ofexpertise in digital information management 48 Architectures Let us consider the following areas: • Content Management • Systems Architecture • Access (Browser support)
- 49. A centre ofexpertise in digital information management 49 Position Today What should we be doing today? • Move away from creating new content in HTML • Move to XHTML as part of the migration • Deploying XML applications • Storing structured information in a neutral database • Using a CMS to manage our content • Deploying B2B applications to avoid human bottleneck (such as RSS) Note that these are aspirations. We will, of course, be constrained by existing systems, resource implications, vested interests, inertia, etc. Note that these are aspirations. We will, of course, be constrained by existing systems, resource implications, vested interests, inertia, etc.
- 50. A centre ofexpertise in digital information management 50 The CMS To The Rescue HTML authoring tools have limitations (as has HTML). A CMS (Content Management System): • Allows fragments to be managed • Allows collections to be managed • Allows resources to be stored in a neutral format (backend database) • Allows resources to be reused • Often provides access control • Often provides workflow processes and project management Issues • CMS can be expensive • CMS can be free but have support implications • Which one to choose? Issues • CMS can be expensive • CMS can be free but have support implications • Which one to choose?
- 51. A centre ofexpertise in digital information management 51 Content Management Storing resources in HTML and GIF/JPEG is: Easy to do and is a low cost solution Makes reuse and management of resources difficult GIF / JPEG XML TIFF / …. On-the-fly or batch conversion WML HTML User-agent Negotiation Content Management System for: • Management of content (content maintenance, metadata management, access rights, project management, …) • Delivery of content (e.g. user-agent negotiation, alternative file formats [such as WML], etc.))
- 52. A centre ofexpertise in digital information management 52 Systems Architecture Issues for you to consider: • Operating System: Should you go for a Unix OS or Windows NT? If Unix, should you go for Linux? • Open Source vs Licensed Solution: Should you go for an open source solution or buy a licensed application? • Package vs Do It Yourself: Should you make use of a pre-packages solution or develop your own solution based on a toolkit (e.g. database, scripting language, …)? There are no global solutions – your choice should be based on expertise available locally, resourcing issues, discussions with partners, solutions provider, etc. There are no global solutions – your choice should be based on expertise available locally, resourcing issues, discussions with partners, solutions provider, etc.
- 53. A centre ofexpertise in digital information management 53 Browser Issues Which approach to browser issues should you take? Web sites should be usable to old browsers as these are still in use and we aim to maximise access. Therefore you should deliver HTML 3.2 / 4.0 and avoid technologies such as JavaScript and CSS. Web sites should be usable to old browsers as these are still in use and we aim to maximise access. Therefore you should deliver HTML 3.2 / 4.0 and avoid technologies such as JavaScript and CSS. Old browsers are broken and fail to implement new technologies which provide (a) richer functionality (b) support for new devices and (c) better support for people with disabilities. Therefore you should use the latest stable versions of HTML (XHTML), CSS, etc. Old browsers are broken and fail to implement new technologies which provide (a) richer functionality (b) support for new devices and (c) better support for people with disabilities. Therefore you should use the latest stable versions of HTML (XHTML), CSS, etc. NOTE • Use of ‘clean’ HTML should degrade gracefully • XHTML is a useful transition • User-agent negotiation may be relevant QUESTION • Should organisations / community implement a browser policy?
- 54. A centre ofexpertise in digital information management 54 Conclusions To conclude: • Standards are important • HTML won’t do the job • XHTML is a useful transition • Many new standards being developed • Need to keep up-to-date and avoid developing systems with built-in obsolescence • We’ll need a CMS to manage richly functional institutional Web services • “Web services” should be important – and we shouldn’t be too concerned about using remote services
- 55. A centre ofexpertise in digital information management 55 Questions Any questions?
Editor's Notes
- #5 There are also a number of specific reasons why use of standards is important for NOF projects: There is a need for the NOF Digitisation programme to ensure that the public funding is properly used There is a need to comply with UK disability legislation There is a need to ensure that digitised cultural heritage resources can be reused There is a need to ensure that digitised cultural heritage resources can be preserved for use by future generations The NOF standards document addresses the standards using a Life Cycle approach: Creation Management Collection development Access Repackaging
- #6 In the days before the Web, access to resources would require use of the vendor’s software (which would often cost). If you used a Unix system, you would find it difficult to read documents created by office applications (word processors, databases, etc.) The Web promised to provide universal access to resources based on use of open standards – who could argue against this aspiration? Universal access to resources is based on the use of open standards. This will provide: Platform and application independence: access (for reading and writing) from PC, Apple Macintosh and Unix system, together with devices such as WAP phones, PDAs, voice browsers, etc. Avoidance of patented technologies: so that licence fees won’t have to be paid to paten holders. Flexibility and architectural integrity: so that new applications can be developed which will interoperate with existing services Long-term access to data: so that resources are not locked into a particular hardware or software system and can continue to be accessed in the long term Ideally we will chose the standards and architectural framework first, and then chose the applications to implement our preferred solution. In practice, it can be difficult to achieve this ideal – and we are likely to find ourselves tempted into using a proprietary solution, perhaps because its familiar to us and is easy to use or it provides rich functionality. Use of this PowerPoint presentation is a good example of use of a proprietary format for these reasons.
- #10 However although proprietary solutions will be tempting, it is worth mentioning the dangers of this approach by looking at a real example. In the mid 1990s between Christmas and New Year Unisys announced that use of the GIF graphical file format (which is widely used on the Web) would require payment of a fee! Unisys had acquired the GIF format from Compuserve and they discovered that the GIF format was based on a compression algorithm for which a patent had been granted). Clearly Unisys felt that charging for use of the GIF format would generate a useful income stream for them. This announcement sent shock waves throughout the Web community. Following much debate, Unisys agreed that they would only seek payment from developer’s of graphical tools which created the GIF format. They would not seek payment from end users of these tools. However end users who used graphical tools for which a developer’s licence had not been made were expected to pay a hefty fee ($5,000) to allow them to use GIF images legitimately. As a response to this, the Web community developed PNG (Portable Network Graphics) – a royalty-free replacement for GIF. There are lessons to be learnt from this incident: File formats which make use of patented technologies which are currently free to use may not continue to be free in the long term (or even short term). Even if the owner of the format promises that use will be free, there is no guarantee that this will continue: the format could be sold to another company; the company could merge with another company; the company could go bankrupt or the company could change its business model. These are real concerns, as we can see from the collapse of many dot com companies and consolidation in the IT industry (e.g. IBM taking over Lotus). There is also the continuing court cases against Microsoft.
- #45 At present each service, whether locally or remote is likely to have its own visual identity, navigational icons, search vocabulary, etc. Users visiting many Web sites will find this confusing.
- #46 In addition information such as collection descriptions and user profiles are associated with each service, making it difficult to share. An exception is the national authentication scheme, Athens, which is shared by national (and potentially local) services. However Athens was designed for authentication of users, and is not suitable for brokered access required by, for example, cross-searching applications using Z39.50.
- #47 We will expect to see access to the national services being provided by brokered applications, such as institutional portals, subject portals, intelligent agents, etc. This will complement direct access by end users to the services.
- #49 Having discussed the importance of standards let us now consider three aspects of the Architectral framework for project deliverables. Namely: Content Management Systems Architecture Access or resources, in particular browser support
- #52 {Note this slide uses a build effect} We could simply chose to create our text and multimedia resources directly – e.g. use of a HTML and graphical authoring tool. These resources could then be delivered to the user’s browser. This approach has the advantage of simplicity: it makes use of existing tools. However this solution is not very flexible and will make it difficult for the service to interoperate with new initiatives. It will also be difficult to maintain. {Move to next build} The preferred solution is to store the resources in a richer format, and then to convert these richer formats to HTML, GIF, etc. The conversion could be done “on-the-fly” or as a batch conversion. This approach will make it easier to reuse the resources to support new uses, such as access to resources on a WAP phone, a PDA, etc. {Move to next build} The use of a Content Management System (a “CMS”) will help organisations to manage their resources. This will include management of the content and associated metadata, management of the creation and maintenance processes (e.g. assigning permissions for access rights, checking compliance with standards, etc.) and management of the delivery (e.g. delivering different formats to different devices).
- #54 An issue many Web developers have to face is whether to target a particular level of browser. There is an argument for using simple, mature formats and avoiding newer technologies such as CSS and JavaScript. This will ensure that old browsers will work, and avoid the complications of using technologies (such as CSS – Cascading Style Sheets) which are implemented badly in certain browsers. {Move to next build} However this approach will mean that it will be difficult to implement new functionality and the richer level of interaction which many end users will now expect (which often requires JavaScript). Newer technologies (such as XHTML) will also make reuse of resources easier to implement. In addition newer formats developed by W3C have been designed to support the needs of people with disabilities. {Move to next build} To summarise: Use of ‘clean’ HTML (i.e. standard) should ensure that Web service degrade gracefully when accessed by older browers XHTML is a useful transition format, and will help to impose a cleaner structure, which will help resources to be transformed into other formats. User-agent negotiation may be relevant – you could transform XHTML into, say, WML for use on a WAP phone. You may also wish to deliver different HTML and CSS files to different browsers – an approach taken by many large Web services.
- #56 Do you have any questions?