UCOS: Enhanced Online Skyline Computation by User Clustering

In this paper, we propose a skyline computation system UCOS (User Clustering based Online Skyline), which divides the computation into offline and online stages. Based on the truth that QoS similarity implies the skyline similarity, the offline stage of UCOS system dose user clustering according to the historical user-service QoS records by given distance metrics. Then, we compute the representative skyline for each cluster standing for the general characters of the users' skylines. Benefit from those offline results, the online stage is able to give a rapid prediction for online skyline request and achieves good online computation performance by doing refinement on the predicted results.