A survey of query result diversification

Nowadays, in information systems such as web search engines and databases, diversity is becoming increasingly essential and getting more and more attention for improving users' satisfaction. In this sense, query result diversification is of vital importance and well worth researching. Some issues such as the definition of diversification and efficient diverse query processing are more challenging to handle in information systems. Many researchers have focused on various dimensions of diversify problem. In this survey, we aim to provide a thorough review of a wide range of result diversification techniques including various definitions of diversifications, corresponding algorithms, diversification technique specified for some applications including database, search engines, recommendation systems, graphs, time series and data streams as well as result diversification systems. We also propose some open research directions, which are challenging and have not been explored up till now, to improve the quality of query results.