July 2007 Volume 10 Number 3 - Educational Technology & Society

Figure 1. The portion of the concept hierarchy of the category “Control structure”
In JLOO, slots provide following information for concepts: 1) recording basic attributes of concepts, i.e., the
metadata of learning objects. For example, the author, data, size, format, location, keywords, etc. 2) defining the
relationships between concepts. A major slot in JLOO is PREREQUISITES. The PREREQUISITES indicates the
concepts that must be learned to gain the prerequisite knowledge before studying a specific concept. A learning
object is not to be provided unless the prerequisite condition is satisfied.
3.2 Building a Repository
All the learning objects in the repository are collected from the Internet according to some criteria. Before putting
them into the repository, they are examined and formalized, and then classified according to the concept hierarchy in
the JLOO. Figure 2 describes these steps and the detailed descriptions are as follows:
Figure 2. Building the Repository
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