Classification of OWL EL ontologies

Table 4 depicts the qualitative results for classification of OWL EL ontologies, hence the table includes the outcomes not only for FaCT++ and HermiT but also for jcel. The NO-REF evaluation outcomes are due to the lack of reference classifications for these cases.

Table 4: Qualitative results for the classification of OWL EL ontologies

	FaCT++	HermiT	jcel
CORRECT	6	6	6
INCORRECT	0	0	0
NO-REF	1	1	1
EXCEPTION	0	0	0
TIMEOUT	0	0	0

Table 5 shows the average loading and reasoning times for the OWL EL ontologies which were classified in less than 200 ms.

Table 5: Loading and classification times of OWL EL ontologies

	FaCT++	HermiT	jcel
# tests	6	6	6
ALT, ms	47	40	40
ART, ms	48	63	194

However, emap ontology was a relatively hard case for FaCT++ and Hermit, which needed 120,187 ms and 7,243 ms respectively; and a very hard case for jcel that needed almost one hour to complete the task. In the case of jcel, the memory restrictions for the evaluation may be a reason for this very high classification time.