A Study on Reverse Top-K Queries Using Monochromatic and Bichromatic Methods

Normally Top-k queries are widely used for retrieving a ranked set of ‘k’ most objects based on the individual user preferences. As an example in online market places customer typically search a ranked set of products that satisfy their needs. From the perspective of a manufacturer, it is imperative that her products appear in the highest ranked positions for many different user preferences. Otherwise the product is not visible to the potential customers. In this paper, we propose a query type namely reverse top-k which leads to a query type that instead returns the set of customers those find a product that belongs to the top-k result of their preferences. It is necessary for the manufacturer to know the market condition based on the competition. The two versions of the proposed query are monochromatic and bichromatic which are introduced in this paper. In monochromatic a geometric interpretation is provided to acquire an intuition of the solution space. In case of bichromatic two query processing techniques are introduced, namely an efficient threshold based algorithm and an algorithm based on materialized reverse top-k views.