Presentation at "XML-enabled Content Management"

Brussels 2001-11-28

Olle Olsson

World Wide Web Consortium (W3C)

[Swedish Office]

• Content management - from where to when
• XML - W3C and standards
• Content - conceptualisation and requirements
• Content use - components of technology
• Semantic Web - towards intelligent content management

Content Management

From where to when

Evolution: technology & business

years	technology	business concerns
(90's)	Web	site management, content management, ...
(80's)	Networks	Object management
(70's)	Databases	Database design & management

Evolution: technology & business

years	management categories	critical activities
(90's)	Knowledge management	acquisition, structuring, use
(90's)	Content management	collection, organisation, publishing
(80's)	Document management	creation, versioning, releasing

Content management as a business task:

• support efficient and high-quality business processes.
• content must evolve as business evolves.
• management of content is typically a decentralised activity.

Content:

• represents information
• is a (small) piece of information
• has structure and description
• has relations to other content

and

• is a business asset.

Content mgmt	Document mgmt
fine-grained assets	large-grained assets
several assets to satisfy need	one asset per identified need
reuse enabled	reuse difficult
new needs may be simpler to support	new needs not easily supported
update localised	update may need global changes

Content representation:

• representation format matching information structure
• needs uniform basic representation technology
• must enable inter-enterprise information exchange

XML

W3C and standards

XML - a technology for information representation:

• enables definition of object types ("XML documents")
• fully generic: all kinds of object types can be defined
• serves as a platform for a large set of specialized representational languages

• XML has been defined by W3C, the World Wide Web Consortium.
• W3C develops standards for the Web.
• Work is done in working groups, staffed by representatives of commercial companies.
• Results are developed through a consensus-based process.

• HTML
• HTTP
• PNG (Portable Network Graphics)
• CSS (Cascading Style Sheets)
• PICS (Platform for Internet Content Selection)
• SMIL (Synchronized Multimedia Integration Language)

• XForms
• XHTML
• XLink
• XML Query
• XML Schema
• XML Signature
• XPath
• XPointer
• XSL / XSLT

Content

Conceptualisation and requirements

• Pieces of content must be described.
• Described by metadata.
• Metadata exist at a level above data (the data of the content pieces).
• Understand what the piece of content contains by inspecting its metadata.
• Needs an open language for expressing metadata.

• Define your types of content pieces as types of XML objects (XML DTD, XML Schema)
• Metadata objects are instances of these types.
• Metadata objects either
• points to its content piece, or
• directly represents the content piece.

• Metadata objects express what the content pieces contain.
• Search for content pieces by search among metadata objects.
• Generic search engines can be used.

Metadata representations must:

• be generic - wide applicability
• support evolution - changes must be easily accommodated
• be open - support decentralisation/virtual enterprises
• be effective - have efficient implementations

Choosing an XML-approach:

• based on a verified foundation
• based on a standard
• based on a globally adopted standard
• enables mappings between different representations.

Using content

Components of technology.

Different categories of use:

• publishing
• source of data ("database")
• decision support
• controlling processes
• communication flow between programs

Publishing involves:

• selection of content pieces
• combination of content pieces
• formatting for external use

and

• delivery

Selection by query:

• query expresses requirements
• evaluate query on a content repository
• resulting content pieces returned

Technology:

• XML Query

Combine set of content pieces:

• content pieces inserted into a structure
• old pieces may be transformed/replaced
• new pieces may be inserted

Technology

• XSL

External use:

• publication in target format:
• web page
• PDF document
• etc.
• data for use in process
• storage in other content repository

Formatting entails transformation

• representation-1 --> representation-2
• expressed through rules
• consistency via standard rule sets

Technology:

• XSLT / XML Formatting objects

Content repository as source of data:

• analogous to database technology/use
• recipient of result typically a program

Advantage:

• avoids duplicated representation

Software access to content repository:

• query repository
• format result for program's use

Technology:

• XML Query
• XSL

Communication between programs:

• programs exchange information
• information exchanged = content pieces

Advantage:

• use same conceptualisation as for content

Program-to-program info exchange involves:

• transform internal --> external format
• communicate
• transform external --> internal format

Technology:

• RDF, Web Services, XML Protocol

Semantic Web

The next step towards intelligent use of web-oriented information

Semantic Web goal:

• "machine-understandable information"

Presently:

• machine-accessible representation of information
• meaning of information ("semantics") is in general not accessible

Representational approaches:

• "A phone of type A costs $45.00"
• TYPE=type-A-phone, PRICE=45.00
• <product type="type-A-phone" price="45.00"/>

Critical insight:

• representation of single objects is not all!

• An objects is of some type.
• Types of objects must be defined.
• Definitions use concepts.
• Concepts are the glue that binds it all together

Ontologies:

• An ontology is the expressed definition of the concepts in a domain.
• Ontologies form the basis for the metadata descriptions of business objects (including content assets)

• The semantic web requires competent technologies/mechanisms.
• These mechanisms will be of use in other domains.
• Content management (and knowledge management) are prime examples of such domains.

The end.

Thank You!

Find more information about W3C standards at:

http://www.w3.org/