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Thinking XML: Learning Objects Metadata

XML knowledge management flourishes in learning technology initiatives

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Level: Introductory

Uche Ogbuji (uche@ogbuji.net), Principal Consultant, Fourthought, Inc.

02 Dec 2003

The education technology field is leading the way with some very interesting uses of XML metadata in practice. A wide range of specifications, standards, and developments exist in the area, but at the center of things is the IEEE Learning Objects Metadata (LOM) specification. In this article, Uche Ogbuji introduces LOM and shows how it can be of interest even to those who have no direct connections with education techology.

The discipline of computer-assisted instruction has always been at the vanguard of knowledge management technology, and has, in general, always been an early user of a wide range of learning environments -- from primary school education through vocational training and enterprise learning resources. Early on, practitioners in this area recognized the importance of personal computers: They were quick to put multi-media CD-ROMs to practical use, and they have also been leaders in the practical application of XML metadata technology.

A hotbed of activity has emerged around how XML content formats and XML-based metadata systems can support learning and instructional technology. In these initiatives the basic unit of interest is the learning object. A learning object is defined and described as follows by the Institute of Electrical and Electronics Engineers, Inc. (IEEE) Learning Technology Standards Committee (LTSC):

[A Learning Object is] any entity, digital or non-digital, which can be used, re-used or referenced during technology supported learning. Examples of technology supported learning include computer-based training systems, interactive learning environments, intelligent computer-aided instruction systems, distance learning systems, and collaborative learning environments. Examples of Learning Objects include multimedia content, instructional content, learning objectives, instructional software and software tools, and persons, organizations, or events referenced during technology supported learning.

Learning objects are also called learning resources, with "resource" taking on a similar meaning to that in Resource Description Framework (RDF). The industry is aggressively adopting XML as the key technology for learning objects and in some respects, activity around learning objects is breaking entirely new ground in semantic Web technology. The educational technology space has never been considered glamorous, and doesn't receive much attention from the outside, but much of what is happening in that area will be of interest to many who read this column. In this article, I shall introduce the field and the significant developments in knowledge management for learning and instruction, focusing on metadata for learning objects.

Many standards, remarkable coherence

Readers of this column will certainly be familiar with areas where numerous competing standards independently address the same problem space. Learning objects have gone through their own profusion of standards, but a good deal of effort has gone into coordination and coherence. The pioneering standardization for learning objects was developed by the Alliance of Remote Instructional Authoring and Distribution Networks for Europe (ARIADNE) where educational metadata and learning object indexing systems were developed in the mid '90s. The Instructional Management Systems project (IMS) and Advanced Distributed Learning (ADL) initiatives emerged in the US in 1997 in an effort to develop standards for distributed learning technologies. The former has become the IMS Global Learning Consortium, whose key work has been in vocabularies and metadata for learning objects (IMS Learning Resource Metadata specification). The latter is the home of the Sharable Content Object Reference Model (SCORM), a Web-oriented data model for content aggregation focusing on the structure and run-time environment for learning objects (see Resources).

SCORM uses XML heavily, especially in defining Course Structure Format, a system for representing course structures so that educational material can interoperate between platforms and systems. SCORM is pretty much accepted as the standard for management of educational content, and its counterpart is a standard for management of educational content metadata -- Learning Object Metadata (LOM) from IEEE LTSC. LOM has roots in ARIADNE's metadata work as well as IMS metadata, and all these organizations have aligned themselves with LOM, as have pretty much all the main educational technology organizations around the world. Both LOM and SCORM were written to be very flexible and extensible, so although learning objects have many variant recommendations, they also have a remarkably large shared foundation.



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LOM basics

LOM defines a Base schema that defines a hierarchy of data elements for learning objects metadata. At the top level of the hierarchy are nine categories, which I describe using the clear definitions from the LOM spec itself:

  1. "The General category groups the general information that describes the learning object as a whole."
  2. "The Lifecycle category groups the features related to the history and current state of this learning object and those who have affected this learning object during its evolution."
  3. "The Meta-Metadata category groups information about the metadata instance itself (rather than the learning object that the metadata instance describes)."
  4. "The Technical category groups the technical requirements and technical characteristics of the learning object."
  5. "The Educational category groups the educational and pedagogic characteristics of the learning object."
  6. "The Rights category groups the intellectual property rights and conditions of use for the learning object."
  7. "The Relation category groups features that define the relationship between the learning object and other related learning objects."
  8. "The Annotation category provides comments on the educational use of the learning object and provides information on when and by whom the comments were created."
  9. "The Classification category describes this learning object in relation to a particular classification system."

For each data element, LOM specifies a name, explanation, size, example value, data type, and other key details. Below is a list of some interesting examples of data elements. In this list I use a common convention of expressing the hierarchy by separating the name of each level with a dot; for example, "General.Identifier.Catalog" would mean "Catalog is a kind of Identifier which is in the General category".

  • General.Title: Name given to this learning object.
  • General.Language: The primary human language or languages used within this learning object to communicate to the intended user.
  • Life Cycle.Version: The edition of this learning object.
  • Technical.Location: A string that is used to access this learning object (might be a URL, for example).
  • Educational.Typical Learning Time: Approximate or typical time it takes to work with or through this learning object for the typical intended target audience.
  • Annotation.Classification: Where this learning object falls within a particular classification system.

Some data elements are meant to have a set of constrained values (enumeration types as programmers would call them). In ontology and metadata technology such as LOM, these collections of fixed and understood values are called vocabularies. Vocabularies are an important concept in LOM and in specifications that build on LOM. IMS develops Vocabulary Definition Exchange (VDEX), a format for machine- as well as human-readable exchange of vocabularies.

LOM in XML

One of the chartered activities of the IEEE LTSC is to develop an XML binding for LOM. This activity is ongoing, but the standard XML binding has not yet been approved and published. I did find a ballot proposal for the binding (by googling for "IEEE 1484.12.3" -- the official name this specification will bear when it's complete). The proposed binding I read is based on W3C XML Schema (WXS). I had hoped that the final specification would support RELAX NG, which I consider to be a superior XML schema definition language, but I assume that WXS was chosen because a large part of the specification involves mapping LOM data elements to the WXS type system; RELAX NG does not have a type system of its own, instead borrowing that of WXS. Still, it would be nice to see normative RELAX NG modules for the content model aspect of LOM (such as which attributes, elements, and text go where).

Listing 1 is an example of what a LOM XML binding instance might look like, based on the proposal I found.


Listing 1. Possible XML format for LOM
<lom xmlns="http://ltsc.ieee.org/xsd/LOMv1p0">
  <general>
    <title>
      <string xml:lang="en">Ecologues</string>
      <string xml:lang="la">BUCOLICA</string>
    </title>
    <language>la</language>
  </general>
  <technical>
    <location type="URI">
      http://classics.mit.edu/Virgil/eclogue.html
    </location>
  </technical>
</lom>

Additional XML design issues will probably be considered before the XML binding is formalized. One thing that struck my eye: I have always advised that URLs be represented in XML attributes, not in content, since they are really intended to be machine-readable; however, in the location element the character data is a URL. This is probably because the value is already qualified by the type attribute. The usual option in such a case is to have another nested element with the URL in an attribute and a human-readable title in that element's content.



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LOM world meets RDF world

A great deal of interest and incipient work has been directed toward reconciling LOM with other metadata standards. Each LOM data element is similar to a Dublin Core metadata element, with some overlap between the two. The very neat Dublin Core metadata editor (see Resources) tool can extract Dublin Core metadata from arbitrary Web pages, and convert the result to LOM or IMS metadata. This serves as a good reminder that metadata intitiatives such as LOM can quickly find applicability outside their immediate discipline. I ran the process on the IBM developerWorks XML zone home page and got the following LOM XML document (based on the draft standard):


Listing 2. LOM metadata extracted from the XML zone home page
<?xml version="1.0" encoding="UTF-8" ?>
<lom xmlns="http://ltsc.ieee.org/xsd/LOMv1p0"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:schemaLocation="http://ltsc.ieee.org/xsd/LOMv1p0
                         http://www.rdn.ac.uk/oai/lom/lom.xsd">

  <general>
    <title>
      <string>developerWorks : XML</string>
    </title>
    <description>
      <string>
        The XML zone on the developerWorks Web site is designed for
        developers. You'll find tools, samples, standards information,
        education, news and events, and links to XML community forums
        and Web sites.
      </string>
    </description>
    <!-- Many other keywords snipped -->
    <keyword>
      <string>xml resources</string>
    </keyword>
    <keyword>
      <string>xml programming</string>
    </keyword>
  </general>
  <lifeCycle>
  </lifeCycle>
  <technical>
    <format>text/html</format>
    <location>http://www-106.ibm.com/developerworks/xml/</location>
  </technical>
  <educational>
    <learningResourceType>
      <source>DCMIType</source>
      <value>Text</value>
    </learningResourceType>
  </educational>
</lom>

An official effort to develop an RDF binding for LOM (IEEE 1484.12.4) is under way. As with the XML binding, nothing has been officially published but a development draft is available, although still more remains to be done. In a positive sign, one of the listed contributors is Eric Miller who did pioneering work with Dublin Core and now works at the W3C. It's good to see various metadata efforts coalesce.



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Wrap-up

Again, LOM and its related standards are very interesting even for those who may not be involved with education technology. Many of these efforts are pushing the state of the art in data modeling, application-neutral data typing, XML-based metadata, and more. I am also quite impressed with the rate of adoption of these metadata technologies by vendors of educational technology. Even though all the pieces are still falling into place for learning objects, developers can try out plenty of tools and demos right away. A lot is going on in this space and many of the pieces are still in motion, so if I missed something or you have new developments to note, please chime in on the Thinking XML discussion forum.



Resources



About the author

Photo of Uche Ogbuji

Uche Ogbuji is a consultant and co-founder of Fourthought Inc., a software vendor and consultancy specializing in XML solutions for enterprise knowledge management. Fourthought develops 4Suite, an open source platform for XML, RDF, and knowledge-management applications. Mr. Ogbuji is a computer engineer and writer born in Nigeria, living and working in Boulder, Colorado, USA. You can contact Mr. Ogbuji at uche@ogbuji.net.




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