不确定移动对象概率Skyline集的查询更新

Skyline查询的研究已从传统的静态Skyline操作延伸到动态的、不确定数据集上的Skyline查询和计算上。研究了移动环境下,查询点位置固定、目标点处于运动状态并且位置不确定情况下的连续概率Skyline计算问题。这个过程中,移动对象与查询对象之间的距离随时间不断变化。移动对象由于其运动状态导致位置无法精确定位,因此移动对象之间的支配关系只能采用概率形式表示,且随时间不断变化。给出了移动对象间的支配概率的定义,以及移动对象Skyline概率的定义,并定义了触发事件来记录对象支配概率发生变化的时刻,实现概率Skyline计算的连续跟踪和动态更新。提出了基于事件触发的连续概率Skyline查询算法(event triggered continuous probabilistic Skyline query for uncertain moving object,U-ECPS),对移动环境下的Skyline集进行连续查询和更新。大量的实验结果验证了U-ECPS算法的有效性。

Updating Queries for Probabilistic Skyline Set of Uncertain Moving Objects

Recently, researchers pay more attention on dynamic and uncertain datasets instead of static objects in Skyline queries field. Aiming at the circumstances that the query point is fixed and target objects are moving with location uncertainty under moving environment, this paper retrieves continuous probability Skyline computation. The distances between moving objects and query point are variable with time continuously. Due to the uncertainty on location, the dominant relationship between moving objects is represented with probability and is constantly variable with time. Firstly, this paper defines the dominated probability and Skyline probability of moving objects. Then, it defines triggered events, which record the time of dominant probability changing, to track and update probabilistic Skyline computation continuously. It also proposes an algorithm of event triggered continuous probabilistic Skyline query for uncertain moving object (U-ECPS) to update the Skyline set. Finally, comprehensive experiments are conducted to demonstrate the efficiency of the proposed algorithm.