Road Alarm: a Spatial Alarm System on Road Networks
College of ComputingGeorgia Institude of Technology
Introduction
Spatial alarms extend the concept of time-based alarms to spatial dimension and remind us when we travel to some predefined location of interest in the future. Spatial alarms are standing spatial triggers and are different than continuous spatial range queries. Thus using techniques for processing continuous spatial range queries to evaluate spatial alarms will deliver very poor performance.
In this software system demonstration, we present the first prototype system of ROADALARM - a spatial alarm processing system for moving objects on road networks. You can reach paper here.Architecture
The spatial alarm processing engine communicates with each mobile client to send spatial alarm alerts or hibernation time, which is a time interval during which the mobile client does not need to wake up and the processing engine does not need to perform alarm checks for this mobile client.
Optimization
To reduce the computation cost while guaranteeing low alarm miss rate, we devise some mobility-aware filters using the concept of steady motion assumption. This enables us to further remove those irrelevant spatial alarms and thus reduce the search space of hibernation time computation. The steady motion assumption refers to the fact that moving objects on the road will move along its current direction for a certain period of time. It is well suited to the road networks since moving objects can move only on the predefined roads in the spatially constrained space.