The conceptual search & navigation paradigms (Structure, Patterns, and Ontology) are based on the use of entities from the knowledge base. The knowledge base is a kind of database that stores the knowledge for a particular domain. It consists of a set of data (entities, entity properties, descriptions, aliases) with respect to a conceptual model, called ontology, and rules for reasoning over this data. Ontology is a formal representation of the concepts within a given domain and the relationships between these concepts.
| Ontology provides a tool for thoroughly exploring the ontology classes of entities and their properties (PROTON Ontology). The Ontology navigation paradigm introduces you to a given domain and helps you create relevant patterns for searching in the data set (especially in the Structure paradigm).
Structure and Patterns provide complex tools for retrieving information. Instead of looking for strings of characters in the content of the document set, like the Keyword search paradigm, conceptual search paradigms search over the graph of the knowledge base and therefore can retrieve entities, as well as documents containing these entities.