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Metadata

Metadata is the "buzz" word in today’s multimedia industry, commonly described as being "Data about data". In other words, metadata provides a means by which the multimedia’s semantics can be described in a structured fashion for use by many varied applications or services. Metadata created solely for use by a single application or toolset goes against all the "hype" surrounding its use ie. Searchability, Extensibility, Re-usability, Scalability. What’s required is a template or standard that everyone conforms to for the exchange and use of media. But even this may not be enough, especially for interoperability issues eg. Spoken language independency

GESTALT Metadata Requirements

During the past few years a number of projects have investigated managing information retrieval and using metadata for education and training. Amongst these are the standardisation activities of the Instructional Management System (IMS) project

http://www.imsproject.org

IMS on which the GESTALT Metadata requirements are based, together with extensions specific to the GESTALT environment, can be found in the Section 2.3.1. of the public deliverable "Gestalt Joint Requirements Specification (D0201)"

GESTALT Metadata Analysis

The two major players in the educational metadata arena, IMS and ARIADNE( http://ariadne.unil.ch/metadata/april98.html ), have declared their support of the IEEE LOM ( http://www.manta.ieee.org/p1484/ltscdocs/wgc/LOMdoc2_5a.doc ) . The IEEE LOM groups its metadata structures into the following 8 categories

• General - Groups all context independent features plus the semantic descriptors for the resource.
• Lifecycle - Groups the features linked to the lifecycle of the resource.
• Meta-metadata - Groups the features of the description itself (rather than those of the resource being described).
• Technical - Groups the technical features of the resource.
• Educational - Groups the educational and pedagogic features of the resource.
• Rights Management - Groups the features that depend on the kind of use envisaged for the resource.
• Relation - Groups features of the resource that link it to other resources.
• Annotation - Allows for comments on the educational use of the resource.

The metadata elements defined in each of the categories are defined using

• subschemes - If they are a collection of data elements themselves;
• data types - If their values are strings, decimals and the like;
• vocabularies - If their values come from an enumerated list.

Metadata elements can be

• mandatory - Must be present,
• optional - May be present,
• conditional - Status depends on absence or presence of value for another data element.

In some instances, the value of a data element may consist of a list of values, rather than a single value. This list can be ordered or unordered. Vocabularies can be Restricted to the list of values specified or Open, in which case the list represents suggested best practice values but others are acceptable.

GESTALT will follow this lead to derive its own structure. However, making the analysis between the three of them highlighted some interesting facts. A summary table of differences is shown below. The full analysis, using IEEE LOM as the analysis base, is available as a Microsoft^® Powerpoint^® presentation. Left-click on the following link to launch the presentation, or right-click to download it (the latter is advised due to the small text used in the presentation). IEEEMappings.ppt.

GEMSTONES

Based upon the IEEE LOM and requirements for the GESTALT resource discovery, learning environment and delivery designs, the following additions or changes have been identified. They can be grouped into four types

• Simple additional enumeration values
• Additional technical requirements for better matching of material to client configuration or capability
• Additional relationship kind to cover material previews
• Simple additional elements
• Enhanced postal address structure
• Date format to include day,month,year
• On-line/Off-line indicator), particularly important for the European market as local connection charges are not free
• Location of alternative media format (or Variant)
• External Rights Managements
When rights metadata is important it should not be held locally with each copy of the material, as seems to be indicated by the IEEE LOM structure. Rather, it should be held as a single instance in some repository so making rights changes, charges, etc simpler to maintain. GESTALT recommends that the INDECS initiative be followed on this matter.
• Quality of Service
Given the wide variety of network types, bandwidths available, media types, media quality, etc Quality of Service (QoS) is an important metadata concept which, in the main, has been overlooked. QoS metadata elements have been identified within GESTALT for demonstration / research purposes. It is not intended to recommend the element details for IEEE LOM consideration at this time.

FUTURE DIRECTIONS

During the course of the project a number of future areas will be tracked and, if relevant, involve participation with other interested parties. These include

• Questions / Testing for On-line Assessment
• Metadata interoperability to overcome European language differences
• Stronger element typing – determine compatability between proposed schemas eg. XML Data, RDF Schema, etc
• Compatability with Dublin Core

© Fretwell Downing Education, 1999.

Updated 26-APR-1999

Send comments or questions to kriley@fdgroup.co.uk