Rachel Heery

1
What are application profiles? (a typology of
schemas)

• Rachel Heery
• UKOLN
• r.heery_at_ukoln.ac.uk
• http//www.ukoln.ac.uk

2
Problem area

• Metadata is required in order to manipulate or
  manage resources
• Metadata is pervasive on the web
• To establish a new service or system implementor
  must decide on appropriate metadata schema.. But
  which one?
• Implementors want to re-use existing schema where
  appropriate

3
Project requirements

• Re-use effort
• Align to inter-working systems
• What schemas exist?
• What schemas are used by similar systems?
• Is this schema current?
• How is it used?

4
Implementors will typically

• Choose subset(s) of existing schema
• Add variety of local extensions to standard
  schema
• Customise definitions
• Establish local good practice
• formulate rules for content
• specify schemes

5
Emerging schemas

• DC-education
• EULER
• EIONET
• MathNet
• RSLP collection description
• http//www.ukoln.ac.uk/metadata/slp/schema/

6
DC-Education proposal

• DC elements and recommended DC qualifiers
• DC-education extensions
• audience mediator
• standard identifier, version
• (DC relation) conforms to
• IEEE LOM IMS elements
• TypicalLearningTime
• InteractivityLevel

7
RSLP Collection Description schema

• dctitle The name of the collection
• dc identifier A formal identifier for the
  collection
• dcdescription A description of the collection
• cldstrength An indication (free text or
  formalised) of the strength(s) of the collection
• cldaccessControl A statement of any access
  restrictions placed on the collection including
  allowed users, charges etc
• .
• ...

8
What is happening in practice

• Implementors are-
• selecting from other metadata sets
• extending existing element sets
• refining definitions
• mandating schemes

9
Data model

• Namespace
• schema
• Elements declared
• Elements defined
• Means of declaring
• new elements

• Application
• profile
• Re-uses elements from
• namespace schema
• Means of declaring what application understands

10
What do we mean by namespace

• Namespace is an identified element set with
  agreed vocabulary
• By means of namespace we can
• Identify registration authority
• Support definition of unique identifiers for
  elements
• Define particular data element sets or
  vocabularies

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Types of schema

• Namespace schema
• Standard element set
• (defined function)
• One registration authority
• Self reliant
• IEEE LOM/IMS
• Dublin Core
• MARC 2000
• indecs
• and so on

• Application profiles
• Mix and match
• (optimised for application)
• One or more registration authorities
• Draws from elsewhere

12
Characteristics of schemas
International standard schemas
Implementation specific schemas
Single namespace
Multiple namespaces
13
Application profile -definition

• Schema consisting of data elements drawn from one
  or more namespaces optimised for a particular
  local application
• Draws on existing namespaces and introduces no
  new data elements

14
Application profile requirements

• Should allow implementor to declare
• limited set of existing elements
• an element is mandatory
• particular schemes must be used with a
  particular element
• a customised definition of an element from
  existing namespace
• rules for content (usage guidelines)

15
Publishing schemas and application profiles

• Why?
• To inform and promote
• To provide authoritative version
• To facilitate inter-working
• To align with other schemas
• How?
• Common syntax
• RDF schemas
• XML schemas

16
Schema Registries
Registry
Registry
Registry

• Registry provides access to collection of schemas
• Adds value by providing services
• search, browse
• crosswalks and mappings
• links to sample metadata instances
• links to annotations
• links to implementations

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Thick registry
Namespace schema
App profile
Mapping
Thick Registry
Sample data
Usage guide
Software tools
Users
18
Thin registry
Namespace schema
App profile
Mapping
Sample data
Usage guide
Thin Registry
Software tools
Users
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SCHEMAS registry

• Prototype thin HTML registry (on web site now)
• Prototype thick RDF Registry will contain
• Application profiles
• Namespace schemas
• Metadata activity reports
• Standards activity reports
• Expert reviews

20
Benefits of common approach

• Re-use existing work where appropriate
• Common tools
• Good metadata management
• Economies of scale
• Effective interworking between services