Date Added: Jan 2010
The location-based alert services can be regarded as the one of the most practical location-based services. For the services, an alert service system for the services alerts mobile device users when they enter into or leave from predefined specific regions, and provides certain services previously asked by the users for special purposes such as security. For providing proper services the alert service system should acquire the location information of the users periodically. However, the system that handles the locations of the users may face serious problems as the number of users increases fast. Hence it is a critical issue to properly adjust the time interval of location data acquisitions while maintaining the accuracy of the services.