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This paper proposes a generic framework for monitoring continuous spatial queries over moving objects. The framework distinguishes itself from existing work by being the first to address the location update issue and to provide a common interface for monitoring mixed types of queries. Based on the notion of safe region, the client location update strategy(More)
A range nearest-neighbor (RNN) query retrieves the nearest neighbor (NN) for every point in a range. It is a natural generalization of point and continuous nearest-neighbor queries and has many applications. In this paper, we consider the ranges as (hyper)rectangles and propose efficient in-memory processing and secondary memory pruning techniques for RNN(More)
Query processing that preserves both the data privacy of the owner and the query privacy of the client is a new research problem. It shows increasing importance as cloud computing drives more businesses to outsource their data and querying services. However, most existing studies, including those on data outsourcing, address the data privacy and query(More)
The processing of kNN and continuous kNN queries on spatial network databases (SNDB) has been intensively studied recently. However, there is a lack of systematic study on the computation of network distances, which is the most fundamental difference between a road network and a Euclidean space. Since the online Dijkstra's algorithm has been shown to be(More)
Location-based applications require a well-formed representation of spatial knowledge. Current location models can be classified into symbolic or geometric models. The former attempts to represent logical entities and their semantics, but requires a large amount of manual effort for describing them. On the other hand, the latter represents the geometric(More)
Owing to recent advances in semiconductor technologies, flash disks have been a competitive alternative to traditional magnetic disks as external storage media. In this paper, we study how transaction recovery can be efficiently supported in database management systems (dbmss) running on slc flash disks. Inspired by the classical shadow-paging approach, we(More)
Location cloaking has been proposed and well studied to protect user privacy. It blurs the accurate user location (i.e., a point withcoordinates) and replaces it with a well-shaped cloaked region (usually a circle or a rectangle). However, to obtain such a cloaked region, all existing cloaking algorithms require to know the accurate locations of all users.(More)
Skyline query processing for location-based services, which considers both spatial and nonspatial attributes of the objects being queried, has recently received increasing attention. Existing solutions focus on solving point- or line-based skyline queries, in which the query location is an exact location point or a line segment. However, due to privacy(More)
Protection of users' location privacy is a critical issue for location-based services. Location cloaking has been proposed to blur users' accurate locations with cloaked regions. Although various cloaking algorithms have been studied, none of the prior work has explored the impact of cloaking on the bandwidth usage of requested services. In this paper, we(More)