Explain the concept of query expansion using WordNet in information retrieval.

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Explain the concept of query expansion using WordNet in information retrieval.

Query expansion is a technique used in information retrieval to improve the effectiveness of search queries by adding related terms or synonyms to the original query. WordNet, a lexical database, is often used for query expansion as it provides a comprehensive collection of words and their relationships.

In the context of information retrieval, WordNet can be utilized to expand queries by identifying synonyms, hypernyms (broader terms), hyponyms (narrower terms), and meronyms (part-whole relationships) of the original query terms. This expansion helps to capture a wider range of relevant documents that may not have been retrieved using the original query alone.

The process of query expansion using WordNet involves the following steps:

1. Tokenization: The original query is broken down into individual terms or tokens.

2. Synonym identification: Each term in the query is matched with its synonyms in WordNet. This is done by leveraging the lexical relationships stored in WordNet, such as the "synonym" relationship.

3. Hypernym and hyponym identification: The hypernyms and hyponyms of each term are also identified. Hypernyms represent broader terms, while hyponyms represent narrower terms. This step helps to capture documents that may contain related concepts.

4. Meronym identification: If applicable, the meronyms of each term are identified. Meronyms represent part-whole relationships, which can be useful in expanding the query to include related terms.

5. Expansion: The identified synonyms, hypernyms, hyponyms, and meronyms are added to the original query, creating an expanded query. This expanded query is then used to retrieve relevant documents from the information retrieval system.

By incorporating WordNet's lexical relationships, query expansion using WordNet enhances the recall and precision of information retrieval systems. It helps to overcome the limitations of the original query by considering a broader range of terms related to the user's information needs.