Abstract
Query search and its expected results on the web are mostly understood and elucidated by users, not machines. Ontology is a tool that describes the meaning of the word and its relations. Researchers introduce ontology in the information retrieval system for solving the problem of semantic understanding. Any information retrieval aims to retrieve relevant documents based on query search. This paper presents ontology-based information retrieval techniques. Two main techniques of information retrieval are discussed from existing literature: query expansion technique and semantic annotation technique. For each of these, we point out the categorization process of the techniques. Also, weight functions are discussed.
