Personal Service Areas for Mobile Web Applications Context-aware Services Architecture

The advent of location-tracking capabilities and their potential in location-based mobile services are major motivations for developing context-aware wireless information delivery systems. Such services let mobile users access information relevant to their situation. The spatiotemporal variables comprising the dynamic context make context-aware applications for mobile users much more complex. In addition to location, elements affecting a locationbased service include travel direction and speed, time of day, personal preferences (such as favorite cuisine, hotel chain, or type of entertainment), and terminal type. A main design consideration for location-based services is the ability to determine a geographical area of relevance for the mobile user. We’ve developed a novel algorithm that tracks user location, derives user direction and speed of travel, and consequently determines a service area’s shape in a computationally efficient manner. To improve user response times, we developed a related layered caching scheme for storing environmental information. Using such a personalized definition of a service area, tourist information services, for example, can wirelessly deliver to tourists’ mobile terminals city information that is better attuned to the users’ mobility context. The “Personalized Tourist Services” sidebar discusses recent research in this area.