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Durable reverse top-k queries on time-varying preference

  • Chuhan Zhang,
  • Jianzhong Li,
  • Shouxu Jiang

摘要

Recently, a query, called reverse top- \(\varvec{k}\) k query, is proposed. The reverse top- \(\varvec{k}\) k query takes an object as input and retrieves the users whose top- \(\varvec{k}\) k query results include the object while the top- \(\varvec{k}\) k query retrieves the top- \(\varvec{k}\) k matching objects based on the user preference. In business analysis, reverse top- \(\varvec{k}\) k queries are crucial for evaluating product impact and potential market. However, the reverse top- \(\varvec{k}\) k query assumes that user’s preference is static. In practice, user preference may change with moods, seasons, economic conditions or other reasons. To overcome this disadvantage, this paper proposes a new reverse top- \(\varvec{k}\) k query, named as durable reverse top- \(\varvec{k}\) k query, without limitation of user’s preference being static. The durable reverse top- \(\varvec{k}\) k query retrieves users who put a given object in the top- \(\varvec{k}\) k favorite objects most of the time during a given time period. An efficient pruning-based algorithm for the queries with fixed \(\varvec{k}\) k is proposed in this paper. For the case of \(\varvec{k}\) k being variable, this paper proposes a pruning-based algorithm with an index to achieve a trade-off between time and space. Experiments on both real and synthetic datasets demonstrate that the proposed algorithms are very efficient.