Ontologies are used in the Semantic Web field for representing domains and modelling knowledge. Ontology evolution is described as the activity of adapting the ontology to new knowledge that occurs as a result of domain changes, while preserving its consistency.
Evolva is an ontology evolution tool that handles information discovery from external data sources (e.g. text documents), data validation, ontology changes, evolution validation and evolution management. The aim of Evolva is firstly to have a complete cycle of ontology evolution, and secondly to decrease user input throughout the evolution process.
One of the key features of Evolva is that it relies on various background knowledge sources for knowledge integration. Background knowledge exists abundantly in various formats such as lexical databases (e.g. WordNet), and also online ontologies that are constantly increasing. Such knowledge would help at the level of adding new knowledge to the ontology. This is where user intervention and decisions are usually most required. For example in the case of a new concept emerging in the domain, a link to existing concepts in the ontology is discovered through harvesting background knowledge. This feature plays an important role in reducing user input during the process of ontology evolution.