CAJ | 학술논문

随着智能移动设备和无线定位技术的飞速发展，使用基于位置服务应用的用户越来越多。特别地，不同于传统的针对固定位置的快照查询，移动的用户往往基于移动轨迹发出连续的查询。在真实和虚拟的空间环境中，障碍物的影响都是广泛存在的，障碍空间内的查询处理技术得到了越来越多的关注，其中，障碍空间内的连续反k近邻查询处理有着重要的应用。对障碍空间中的连续反 k 近邻查询问题进行了定义和系统的研究，通过定义控制点和分割点，提出了针对该问题的处理框架。进一步地，提出了一系列的过滤和求精算法，包括剪枝数据集、获取障碍物、剪枝和计算控制点和更新结果集等处理策略。基于多种数据集对所提出的算法进行了实验评估。与针对每个数据点进行k近邻计算的基本方法相比，这些方法可以大幅度提高查询处理的CPU和I/O效率。
수착지능이동설비화무선정위기술적비속발전，사용기우위치복무응용적용호월래월다。특별지，불동우전통적침대고정위치적쾌조사순，이동적용호왕왕기우이동궤적발출련속적사순。재진실화허의적공간배경중，장애물적영향도시엄범존재적，장애공간내적사순처리기술득도료월래월다적관주，기중，장애공간내적련속반k근린사순처리유착중요적응용。대장애공간중적련속반 k 근린사순문제진행료정의화계통적연구，통과정의공제점화분할점，제출료침대해문제적처리광가。진일보지，제출료일계렬적과려화구정산법，포괄전지수거집、획취장애물、전지화계산공제점화경신결과집등처리책략。기우다충수거집대소제출적산법진행료실험평고。여침대매개수거점진행k근린계산적기본방법상비，저사방법가이대폭도제고사순처리적CPU화I/O효솔。
With the rapid development of smart mobile devices and wireless location techniques, more and more users tend to attempt location-based service. Specifically, mobile users usually request continuous queries based on moving trajectories instead of traditional snap-shot queries for fixed locations. As obstacles can be found everywhere in the real-world or virtual space, more and more attentions has been paid on query processing techniques in the obstructed space. Notably, continuous reversek-nearest neighbor queries in obstructed space are widely used. This paper presents an in-depth study on the problem of moving reversek-nearest neighbor queries in obstructed spatial databases. By defining control points and split points, the processing framework for this problem is constructed. Furthermore, several pruning and verification algorithms, including data points reduction, obstacles retrieving, control points calculating and results set updating, are proposed to improve the query efficiency. Extensive experimental evaluation is conducted based on various datasets. Compared with the basic method which computes thek-nearest neighbors for each data point, the proposed methods can significantly improve CPU and I/O efficiency.