Probabilistic Range Query over Uncertain Moving Objects in Constrained Two-Dimensional Space

Abstract

This article proposes an PQR search method for probabilistic objects. The main idea of our method is to use a strategy called pre-approximation that can reduce the initial problem to a highly simplified version, implying that it makes the rest of steps easy to tackle. In particular, this strategy itself is pretty simple and easy to implement. Furthermore, motivated by the cost analysis, we further optimize our solution. The optimizations are mainly based on two insights: (i) the number of effective subdivisions is no more than 1; and (ii) an entity with the larger span is more likely to subdivide a single region. We demonstrate the effectiveness and efficiency of our proposed approaches through extensive experiments under various experimental settings.

Path–Based Continuous Spatial Keyword Queries

“…Spatial queries have been extensively studied in database community. Specifically, enormous focuses have shifted to range queries [16,[23][24][25][26][27] and k nearest neighbor queries [2, 4-6, 9, 18]. Next, we will introduce the works on them respectively.…”

“…To alleviate the effect the frequent object updates, Wang et al [24] develop the Shortest-Distancebased Tree (SD-Tree), which supports incremental computation of answer sets using retrieved paths. Literature [25][26][27][28] explore the range queries with the assumption that objects move on the Euclidean space. Specifically, [26,28] consider an uncertainty model, in which the motion of objects is uncertainty.…”

“…Literature [25][26][27][28] explore the range queries with the assumption that objects move on the Euclidean space. Specifically, [26,28] consider an uncertainty model, in which the motion of objects is uncertainty. Chung et al [28] propose to transform moving objects into points by hough transform, and then index them with R-tree.…”

“…Chung et al [28] propose to transform moving objects into points by hough transform, and then index them with R-tree. In [26], by transforming the irregular motion areas to polygon regions, the initial problem can be reduced to a simplified version. Wu et al [27] study the continuous range queries over moving objects but stationary queries.…”