Synonyms

Maximum update interval

Definition

The maximum update interval in moving objects databases denotes the maximum time duration in-between two subsequent updates of the position of any moving object. In some applications, a variation of the maximum update interval denotes the time duration within which a high percentage of objects have been updated.

Main Text

In moving objects databases, there exist a population of moving objects, where each object is usually assumed to be capable of transmitting its current location to a central server. A moving object transmits a new location to the server when the deviation between its real location and its server-side location exceeds a threshold, dictated by the services to be supported. In general, the deviation between the real location and the location predicted by the server tends to increase as time passes. Even the deviation does not increase, it is also necessary to inform the server periodically that the object still exists in the system. In keeping with this, a maximum update interval is defined as a problem parameter that denotes the maximum time duration in-between two updates of the position of any moving object.

This definition is very helpful to index and application development especially those with functions of future prediction. Given such a time interval, trajectories of objects beyond their maximum update interval when the objects will definitely be updated usually do not need to be considered. In other words, the maximum update interval gives an idea of a time period of validity of current object information.

Cross-References