Analysis of Emergency Alert Services and Systems

Abstract

Location-based services have received increasing attention in recent years. In location-based services, wireless broadcast is an efficient method to support the large number of users. In wireless broadcast environments, existing research proposed to support range search and k-nearest neighbor search, may tune into unnecessary indexes or data objects. In this paper, we propose a novel spatial query processing using histogram that supports location-based services in wireless broadcast environments. Spatial query processing using histogram summarizes the map information of spatial data in divided space. Therefore we reduce the energy consumption and access latency using spatial indexes that based on the Hilbert Curve. This paper also presents search algorithms for two common spatial queries, window queries and k-nearest neighbor queries. The simulation results show that our methods outperform the existing algorithm based on the Hilbert curve on the air.