Information Retrieval

Information retrieval is the science of searching for information in a document, searching for documents themselves, and also searching for metadata that describes data, and for databases of texts, images or sounds. It's closely associated with the development and usage of computer-based storage and retrieval mechanisms. This process primarily aims at providing the right information at the right time and in the right place.

How Information Retrieval works

Information retrieval system starts when a user enters a query into the system. Queries are formal statements of information needs, for example search strings in web search engines. During the process, the system compares the queried search terms with the information or data stored in its databases or it often retrieves metadata documenting other original resources.

The system then comes up with a result which could be in the form of documents, images, audio files, web pages or other types of data sources. The retrieved results are then ranked based on relevancy criteria set by the system.

There are several techniques applied in the Information Retrieval process including Boolean Model, Vector Space Model, Probabilistic Model, and Machine Learning Model. All these models have different algorithms and methodologies to determine the relevance, but all serve to provide the most pertinent information as a response to the user query.

These systems are not just limited to search engines, but also widely used in various other applications like database management systems, data mining, text mining, image retrieval and others.