Ontology Evolution
Contents
Evaluation of Ontology Evolution Process
This page describes the evaluation done for the ontology evolution process along with screen shots of the ontology being evolved. The output of the system is captured for the following ontology changes:
- Ontology Expansion
- Support Update
- Concept Removal
- Ignore Evidence
We also show the support information associated with each concept. All the experiments were done for thresholds (1) match threshold (used to match incoming evidences with concepts in the ontology) = 0.7 and (2) Support update threshold (used to do a support update rather than expansion) = 0.9.
Ontology expansion
Support Update
Concept Removal
There are multiple evidences in this run just to simulate removal of concepts. The concept removal is performed by repeatedly running the ontology evolution process for the same set of evidences. The effect of such a run is that some concepts that do not have support even after processing of a number of evidences mentioned in the properties file (in this case it was set to 30 evidences), will have it’s support reduced. This reduction in support will result in its removal from the ontology based on the mean threshold.
Note: Even though concept like SomeUnrelatedConcept is shown in C, it could not be added to the ontology due to the absence of position information. Such concepts can be suggested as possible addition due its repeated arrival as evidence and a human can decide if this concept is to be added to the ontology. Instead, the user may decide to make the addition automatic by the machine.
Concepts ElectricityService and NaturalGasService has its mean decayed below threshold mean value (0.3, set in the properties file) and hence removed from the ontology.
Ignore Evidence
An evidence is ignored iff, Constraints do not allow expansion of the ontology and support associated with the evidence is lower than all the concepts in the ontology. This happens when the ontology has expanded to it's maximum bound by its constraints.
Evolution w.r.t Internal and External Evidences
Internal Evidences
External Evidences
