There are two types of ontology modules. One is called decomposing module, and the other is called bonding module. Mp.d represents the decomposing module of resource object p and its hierarchy of its subset of resource objects, and contains only “is_a” or “has_a ” relationships between the resource objects in the hierarchy; that is, . Clearly, the traditional ontology models without explicit semantic relationships other than “is_a” or “has_a” between the concepts are all Mp.d.Mp.b represents the bonding module of resource object p and its semantically related set of resource objects with the semantic relationships other than is_a or has_a; that is,Mp.b=p, Cp, Rpisa|hasa. Clearly, the traditional ontology models do not have Mp.b.
The top ontology module is a special module that is the bonding module of the top concept of the ontology. A bottom ontology module is a special module that is a simple resource object of a static web page.