In order to process CKNN queries on the basis of TPR-tree efficiently,a new spatio-temporal distance metrics minmaxdist(t) was presented as a pruning upper bound.

• 针对基于TPR树索引的连续k近邻查询,引入了一种新的时空距离度量最小最大距离函数作为TPR树索引搜索时节点剪枝上界。