时间区间上的不确定移动对象距离范围查询

针对目标对象与查询发出者皆为不确定移动对象的情况，提出了一种时间区间上的距离范围查询（DRqTI）.此类查询搜索出数据集中在给定时间区间内，到查询发出者距离不超过阈值的目标对象，查询结果中包含对象满足查询条件的有效时间段和匹配度.提出了基于轨迹、基于时间区间和基于距离的三种剪枝策略，并给出了精炼和匹配度计算方法，在此基础上设计了查询处理算法.实验分析表明，三种剪枝策略中基于距离的方法性能最佳，提出的算法能有效处理DRqTI问题.

Distance-Based Range Queries over Uncertain Moving Objects within Time Intervals

Aiming at the scenarios that the query issuers and query sender are uncertain moving objects, a new type of queries named DRqTI (Distance-based Range query within a Time Interval) is defined. The DRqTI searches out the target object in the dataset, which satisfies that the distance to the query issuer does not exceed the threshold value in a given time interval. And query results contain the suitability and valid time intervals which satisfy the condition. Three pruning strategies, namely trajectory-based, time-based and distance-based rules are designed. Furthermore, algorithms that integrate the calculation method of refining and matching degree are developed. On this basis, a query processing algorithm is designed. The experimental analysis shows that distance-based method is the best among three methods and the proposed algorithm can deal with DRqTI problem efficiently.