“…Since Börzsönyi et al first introduced the skyline operator in the database filed, many proposals of improved algorithms, output size sensitive algorithms, top‐ k skyline, query optimizations, and variations of skyline query have been investigated. Regarding the concept of group‐based skyline, the most related works are Im et al, Li et al, Chung et al, Liu et al, and Zhang et al In Im et al, Li et al, Chung et al, and Zhang et al, each group is represented by a representative point, whose attribute values are aggregated over the corresponding attribute values of points in the group. The groups are then compared by their representative points as conventional skyline computation.…”