• Common domain ontologies: they are obtained from other
sources and developed in a given specific domain (i.e.,
engineering, music and law) for their own purposes. According
to the common precondition for the reusability of an ontology,
this kind of ontologies are tend to be overgeneralised and to
omit relevant details. Thus, they require considerable
modifications before they can be reutilised for the proposed
ideas creation.
• Legacy ontologies: they were used to be knowledge bases
working in the ideas creation system. However, along with the
continued development of researches, the legacy ontologies can
be insufficient, which is out-of-date ontologies. In contrast, the
ontologies are constructed and worked recently with sufficient
information are up-to-date ontologies. The out-of-date
ontologies require update by merging new ontologies
developed by the knowledge extraction. The up-to-date
ontologies are suitable to be reutilised directly as the
knowledge base for further idea generation.